WO2022129959A1

WO2022129959A1 - Catheter

Info

Publication number: WO2022129959A1
Application number: PCT/GR2021/000032
Authority: WO
Inventors: Giannis STEFANIDIS
Original assignee: Stefanidis Giannis
Priority date: 2020-12-18
Filing date: 2021-05-20
Publication date: 2022-06-23
Also published as: GR1010093B

Abstract

The present invention refers to a catheter (1) comprising a catheter shaft (2) that extends along a longitudinal axis (500) and comprises a lumen (21) defined by a catheter shaft wall (24), a flexible moving element (3), a surgical tool (3) connected to the flexible moving element (3), a distal piston (8) and a proximal piston (9). The distal piston (8) and the proximal piston (9) are arranged in the lumen (21) and a space between the distal piston (8) and the proximal piston (9) is filled with an incompressible fluid. The distal piston (8) is connected to the flexible moving element (3). The flexible moving element (3) is arranged in the catheter shaft (2) in such a way that the flexible moving element (3) is at least partially circumferentially supported by the catheter shaft wall (24) so that a movement of the proximal piston (9) in a direction from a proximal shaft end (29) of the catheter shaft (2) to a distal shaft end (28) of the catheter shaft (2) causes a movement of the surgical tool (5).

Description

CATHETER

Description

The present invention refers to a catheter comprising a surgical tool. The catheter of the present invention can also be characterized as a medical catheter.

Catheters have been used for years in many medical applications for humans and animals, as they provide access to the body in a minimally invasive way.

For example, catheters are widely used in most endovascular applications. Due to their minimal invasive character, the treatment of blood vessel pathologies can be achieved without considerable postoperative pain and the need of a general anaesthesia during the operation or a long hospitalization of the patient. An endovascular catheter is known from WO 2016 203277 A1.

It is an object underlying the present invention to suggest a compact catheter with a high design flexibility and ease of use and manufacture, which can also be used in a variety of medical applications.

The solution to said object is achieved by a catheter with the combination of features of the independent claim. The dependent claims contain advantageous embodiments and aspects of the invention.

In particular, the catheter comprises a catheter shaft, a flexible moving element, a surgical tool connected to the flexible moving element, a distal piston and a proximal piston. The catheter shaft extends along a longitudinal axis and comprises a lumen defined by a catheter shaft wall. The distal piston and the proximal piston are arranged in the lumen and a space between the distal piston and the proximal piston is filled with an incompressible fluid. The flexible moving element is connected to the distal piston and arranged in the catheter shaft in such a way that the flexible moving element is at least partially circumferentially supported by the catheter shaft wall so that a movement of the proximal piston in a direction from a proximal shaft end of the catheter shaft to a distal shaft end of the catheter shaft causes a movement of the surgical tool. It is noted that the terms “distal piston" and “proximal piston” mean that the proximal piston is closer to the proximal shaft end of the catheter shaft than the distal piston is to the proximal shaft end. In other words, the distal piston is closer to the distal shaft end of the catheter shaft than the proximal piston is to the distal shaft end.

In more details, a movement of the proximal piston in a direction from the proximal shaft end of the catheter shaft to the distal shaft end of the catheter shaft is transferrable via the incompressible fluid to the distal piston and from the distal piston to the flexible moving element. By being at least partially circumferentially supported by the catheter shaft wall as described above, the flexible moving element is movable by the distal piston in such a way that its movement causes a movement of the surgical tool. In other words, the flexible moving element is arranged in a way that it is laterally supported by the catheter shaft wall so that the flexible moving element, even though it is itself bendable, can push the surgical tool. Should not have been for the circumferential support of the flexible moving element provided by the catheter shaft wall, the flexible moving element would, at least partially, bend when being pushed by the distal piston, and thus would not be able to move the surgical tool. To put it differently, the flexible moving element is advantageously confined by the catheter shaft wall so that the flexible moving element functions as a stiffer element when being pushed, so that the flexible moving element can transmit its movement to the surgical tool. Thus, the catheter shaft wall acts as a restriction and support element for the flexible moving element so that the flexible moving element is supported throughout its movement in the lumen such that its movement results in a corresponding movement of the surgical tool. In particular, the catheter shaft wall provides to the flexible moving element the stiffness that the flexible moving element inherently lacks and hence needs in order to be able to move the surgical tool. It is understood that the flexible moving element acts as a movement and force transmitting element that is configured to transmit a force applied to the flexible moving element and thus a movement to the surgical tool. However, the flexible moving element is/remains capable of being bent, when the catheter, in particular the catheter shaft, is forwarded through curved paths, e.g. tortuous blood vessels, of the body of a patient.

The catheter of the present invention has a compact structure, as due its suggested configuration it is sufficient that the catheter shaft comprises only one lumen for receiving a means for transmitting a force and thus a movement to the surgical tool. In the present invention, said means corresponds to the arrangement of the proximal piston, the distal piston and the flexible moving element as described above. More specifically, the present invention allows for a reduction of a minimum outer dimension, in particular a minimum diameter, of the catheter/catheter shaft by about 30% compared to a catheter with a catheter shaft requiring two lumens for receiving a means for transmitting a movement to the surgical tool. This in turn has the advantage that the catheter can be used in a large variety of applications and more particularly in applications where blood vessels, lumens and cavities of small dimensions of a human or animal body should be accessed. Further, due to the flexible nature of the moving element the catheter can be still bent as a whole, while the catheter is provided with a mobile surgical tool that is movable relative to the catheter shaft. Thus, the flexible moving element does not alter the flexible nature of the catheter as a whole. It is noted that in the framework of the present invention, a catheter is in particular understood as a device having a flexible (catheter) shaft for insertion into a body cavity, duct, canal, vessel or passageway of a patient and being configured to deliver to or withdraw fluids from a patient through its catheter shaft and/or distend a passageway and/or place a surgical tool at a target site inside the patient’s body in order to cause a modification of the body cavity, duct, canal, vessel or passageway.

Continuing with the advantages of the catheter of the present invention, the fact that only one lumen is needed for accommodating the arrangement of the flexible moving element, the distal piston and the proximal piston offers a great flexibility in view of the spatial arrangement of the lumen with respect to any further lumens that might be formed in the catheter shaft, such as a lumen for transferring fluids therethrough and/or receiving a guidewire. More specifically, the requirement of only one lumen in the catheter shaft of the catheter of the present invention for receiving the means for moving the surgical tool forward is particularly advantageous, when a further lumen is formed in the catheter shaft for transferring fluids, e.g. body fluids, therethrough, and said further lumen needs to have a large cross-section in order to facilitate the transfer of large fluid quantities. That is because the single lumen for the means for moving the surgical tool leaves free space in the catheter shaft so that the further lumen can be formed with the necessary size.

Further, as the surgical tool can be moved by the arrangement of the flexible moving element, the distal piston and the proximal piston provided in a single lumen, said arrangement can have a small length, in particular compared to a catheter shaft that requires two lumens for receiving a means for transmitting a movement to the surgical tool. Thereby, friction losses during the movement of the flexible moving element, the distal piston and the proximal piston inside the lumen can be reduced and the risk of a potential warping of the catheter shaft can also be reduced or even eliminated.

Moreover, using an incompressible fluid between two pistons for transmitting a movement is advantageous as a controlled transmission of the movement between the distal and the proximal piston can be achieved. In addition, a length of the space filled with the incompressible fluid and a length of the flexible moving element in the direction of the longitudinal axis of the catheter shaft can be adapted to the application for which the catheter is intended. For example, the space filled with the incompressible fluid can be chosen such that the flexible moving element has a smaller length, if the catheter is made to be used in lumens with large tortuosity. On the other hand, the length of the moving flexible element can be chosen to be shorter, if tortuous lumens should be accessed with the catheter. Further, the force being transferred from the proximal piston to the distal piston is independent from the speed of movement of the proximal piston. As an incompressible fluid, water or a water solution can be used for filling the space between the distal piston and the proximal piston. In addition, the suggested catheter does not require a complex manufacturing process, while it also enables a simple and intuitive handling by a doctor. In particular with regard to the latter aspect, a pushing force, i.e. a force applied by the doctor to the proximal piston towards the distal shaft end of the catheter shaft, is translated in a movement of the surgical tool in a direction towards the distal shaft end. Further, a pulling force, i.e. a force applied by the doctor to the proximal piston towards the proximal shaft end of the catheter shaft is translated in a movement of the surgical tool in a direction towards the proximal shaft end.

It is noted that a movement of the proximal piston in a direction from the distal shaft end of the catheter shaft to the proximal shaft end of the catheter shaft effects a corresponding movement of the surgical tool as the movement of the proximal piston results in a build up of negative pressure in the space between the proximal piston and the distal piston, what in turn causes the fluid and the distal piston to be moved/pulled in the same direction with the proximal piston. The movement of the distal piston is then transferable to the flexible moving element, which in turn pulls the surgical tool connected thereto.

It is further noted that the term “at least partially" in the expression “at least partially circumferentially supported” refers to the term “circumferentially”. This means that the flexible moving element is supported at least over a part of its whole circumference at a given crosssection. In particular, in the framework of the present invention, the flexible moving element is partially or completely circumferentially supported inside the lumen regardless of the form/shape of the inner surface of the catheter shaft wall defining the lumen or in other words regardless of the form/shape of the lumen, when/as long as the flexible moving element moves substantially or only along its longitudinal axis and does not move or bend laterally. A partial circumferential support is particularly provided when there is a partial circumferential contact between the flexible moving element and the lumen, whereas a complete circumferential support is particularly provided when there is a complete circumferential contact between the flexible moving element and the lumen.

Preferably, the flexible moving element is completely circumferentially supported by the catheter shaft wall. This means that the flexible moving element is supported over its whole circumference at a given cross-section.

Advantageously, the flexible moving element is longitudinally movably arranged in the lumen. More particularly, the flexible moving element is extractably arranged in the lumen. This means that the flexible moving element can be moved out of the lumen due to the at least partial circumferential support by catheter shaft wall so that the flexible moving element can move the surgical tool. Advantageously, the surgical tool, the flexible moving element, the distal piston and the proximal piston each have two end positions. In the first end position (proximal end position), a proximal end of each of these components is at its closest position with respect to the proximal shaft end of the catheter shaft, whereas in the second end position (distal end position) the proximal end of each of these components is at its furthest position with respect to the proximal shaft end of the catheter shaft. Thus, each of these components is movable between its corresponding first end position and its second end position. The difference between the first end position and the second end position of the surgical tool corresponds to the range of motion of the surgical tool, in other words the maximum distance that the surgical tool may cover during its movement. In particular, the flexible moving element is extracted in its second end position and retracted in its first end position.

Advantageously, the flexible moving element can be partially or completely arranged inside the lumen, when the flexible moving element is in its first end position corresponding to the first end position of the surgical tool. Preferably, when the flexible moving element is in its second end position corresponding to the second end position of the surgical tool, the flexible moving element may be partially arranged inside the lumen. However, it is also possible that the flexible moving element is arranged completely outside the lumen in its second end position. In other words, it can be said that the flexible moving element is partially arranged inside the lumen between its first end position and second end position, i.e. between the first end position and the second end position of the surgical tool.

The flexible moving element may be substantially arranged in the lumen in and/or between its first end position and/or second end position. "Substantially" means in particular that more than 50%, preferably more than 60%, more preferably more than 70%, even more preferably more than 80% of a total length of the flexible moving element is arranged in the lumen.

The inner surface of the catheter shaft wall defining the lumen may preferably be configured such that it provides the at least partial circumferential support to the flexible moving element over only a portion of its length or over its whole length.

Advantageously, the distal piston and the proximal piston are arranged inside the lumen for their whole range of movement between their corresponding first and second end positions.

The moving element is advantageously flexible over its whole length. Furthermore, a flexibility of the flexible moving element may vary along its length. This allows the flexible moving element to be adapted to a respective application of the catheter.

According to an advantageous embodiment of the present invention, a distal portion and/or a proximal portion of the flexible moving element has/have a smaller flexibility than its middle portion, i.e. the portion between the distal portion and the proximal portion of the flexible moving element. This is in particular of advantage, when the surgical tool is directly connected to the flexible moving element. In this case, the distal portion having a smaller flexibility than the middle portion may correspond to the portion of the flexible moving element that is outside the lumen, when the flexible moving element is in its second end position. The distal portion and/or the proximal portion of the flexible moving element preferably correspond to connecting portions of the flexible moving element with other components of the catheter.

Preferably, the flexibility of the flexible moving element is such that a flexibility of the catheter shaft and/or the catheter with the flexible moving element is not more than 20%, preferably not more than 10%, most preferably not more than 5%, different, in particular larger, than a flexibility of the catheter shaft and/or the catheter without the flexible moving element.

In the framework of the present invention, the term “flexible” describing a component, in particular the moving element, means advantageously that the respective component, in particular the moving element, is bendable by its own weight when it is fixed at at least one of its ends. In other words, the term “flexible" means that the respective component, in particular the moving element, cannot support/carry/bear its own weight without being bent when it is fixed at at least one of its ends. It is noted, however, that bending does not mean that the respective component collapses due its own weight when it is fixed at at least one of its ends. In other words, the flexible component may only partially carry its own weight.

Advantageously, the surgical tool is connected to the flexible moving element at a distal portion and/or distal end of the flexible moving element.

Further, the distal piston is advantageously connected to the flexible moving element at a proximal portion and/or proximal end of the flexible moving element.

It is preferred that at least the flexible moving element portion that is movably arranged or arrangeable/movable in the lumen between the first and the second end positions of the flexible moving element has a cross-sectional area over at least a part of its whole length, i.e. over only a part of its whole length or over its whole length, that is at least 80%, more preferably at least 85%, even more preferably at least 90%, even more preferably at least 95%, most preferably substantially 100%, of a cross-sectional area of the lumen.

Most preferably, the flexible moving element has over its whole length a cross-sectional area that is at least 80%, more preferably at least 85%, even more preferably at least 90%, even more preferably at least 95%, most preferably substantially 100%, of a cross-sectional area of the lumen. In particular, when the lumen and at least the flexible moving element portion that is movably arranged or arrangeable/movable in the lumen between the first and second end positions of the flexible moving element are each formed as a circular cylinder, it is preferred that at least said flexible moving element portion has over at least a part of its whole length, i.e. over only a part of its whole length or over its whole length, a diameter that is at least 80%, more preferably at least 85%, even more preferably at least 90%, even more preferably at least 95%, most preferably substantially 100%, of a diameter of the lumen.

Most preferably, when the lumen and the whole flexible moving element are each formed as a circular cylinder, it is preferred that the flexible moving element has over its whole length a diameter that is at least 80%, more preferably at least 85%, even more preferably at least 90%, even more preferably at least 95%, most preferably substantially 100%, of a diameter of the lumen. Advantageously, a fit between the flexible moving element and the lumen is a clearance fit.

It is noted that when referring to the shape of a portion or the whole of the flexible moving element, the shape of a main body of the flexible moving element that extends in the direction of its longitudinal axis, without taking into account any potential protrusions that may act as connecting portions of the flexible moving element with a further component of the catheter, i.e. when the flexible moving element substantially extends along its longitudinal axis, is in particular meant within the scope of the present invention. Thus, a length of a portion or the whole of the flexible moving element means in particular a length of the portion or the whole of the flexible moving element in the direction of its longitudinal axis, respectively.

It is further noted that the term “at least the flexible moving element portion” means in particular the portion of the flexible moving portion, that is arranged in the lumen during its movement from the first end position to the second end position or vice versa.

By choosing the dimensional relationship of the flexible moving element and the lumen as presented, it can be ensured that most of the force with which the flexible moving element is pushed can be transferred to the surgical tool and cause it to move, in particular be pushed. The term “substantially" in connection with the terms “cross-sectional area" and/or “diameter" means in particular that the lumen and the flexible moving element are produced within the technical tolerances of the method(s) used to manufacture said elements.

Preferably, the catheter shaft has a cylindrical shape, in particular with a circular cross-section, i.e. the catheter shaft is in particular a circular cylinder. However, the cross-section of the cylindrical catheter shaft may also have another shape, e.g. the cross-section may be oval. A cylindrical catheter shaft is easy to be manufactured and can easily be forwarded through a body lumen of a patient. Preferably, at least the flexible moving element portion that is movably arranged or arrangeable/movable in the lumen between the first and the second end positions of the flexible moving element has over at least a part of its whole length, i.e. over only a part of its whole length or over its whole length, the same shape with the lumen. Most preferably, the flexible moving element has over its whole length the same shape with the lumen.

Preferably, the flexible moving element is arranged in the lumen in such a way that the flexible moving element portion that is movably arranged or arrangeable/movable in the lumen between the first and the second end positions of the flexible moving element has over at least a part of its whole length, i.e. over only a part of its whole length or over its whole length, a shape that is complementary to a shape of the lumen. For example, if both the flexible moving element and the lumen have an elliptical cross-section, the flexible moving element is arranged in the lumen in such a way that a major axis and a minor axis of the flexible moving element are aligned with a major axis and a minor axis of the lumen, respectively.

According to an advantageous embodiment, at least the flexible moving element portion that is movably arranged or arrangeable/movable in the lumen between the first and the second end positions of the flexible moving element, in particular the whole flexible moving element, is formed as a circular cylinder.

Preferably, the lumen is formed as a circular cylinder.

According to an alternative advantageous embodiment of the present invention, the catheter shaft may comprise at least one frustoconical region, in particular a plurality of frustoconical regions. In addition to the at least one frustoconical region, the catheter shaft may also comprise at least one cylindrical region. Forming the catheter shaft with at least one frustoconical region has the advantage that a sliding friction between the catheter shaft and the wall of a body lumen, inside which the catheter may be pushed forward, or between the catheter shaft and a casing arranged on the catheter shaft and having a different shape than the catheter shaft, can be reduced due to the smaller contact between the catheter shaft and the lumen or the catheter shaft and the casing, respectively.

Advantageously, the catheter shaft comprises a distal shaft wall opening that is formed in a distal circumferential area of the catheter shaft and communicates with the lumen. In an embodiment of the present invention, the flexible moving element is configured to move the surgical tool out of the catheter shaft through the distal shaft wall opening. In another embodiment of the present invention, a portion of the flexible moving element is always located in the distal shaft wall opening. This means that the flexible moving element is partially arranged in the distal shaft wall opening in and between its first end position and second end position. The distal shaft wall opening can advantageously be formed as a recess in the catheter shaft wall, in particular as a through recess in a transverse direction of the catheter shaft.

According to an advantageous embodiment of the present invention, the lumen extends from the proximal shaft end of the catheter shaft in a direction towards the distal shaft end of the catheter shaft. This means in other words that a proximal end of the lumen coincides with the proximal shaft end of the catheter shaft. In this case, a control element for controlling the surgical tool may exit through an opening at the proximal end of the lumen so that it can be manipulated by the doctor. It is noted that the formulation “in direction towards the distal shaft end of the catheter shaft" does not mean that the lumen extends to, i.e. reaches, the distal shaft end of the catheter shaft, but indicates the direction in which the lumen extends.

According to an alternative advantageous embodiment of the present invention, a proximal end of the lumen is spaced apart from the proximal shaft end of the catheter shaft. In other words, the lumen according to this embodiment does not extend from the proximal shaft end of the catheter shaft in a direction towards the distal shaft end of the catheter shaft.

A proximal shaft wall opening may advantageously be formed in a proximal circumferential area of the catheter shaft, wherein the proximal shaft wall opening communicates with the lumen. The proximal piston can thus be controlled via the proximal shaft wall opening. The proximal shaft wall opening can advantageously be formed as a recess in the catheter shaft wall, in particular a through recess in a transverse direction of the catheter shaft.

According to an embodiment of the present invention, the surgical tool can be directly connected to the flexible moving element. It is understood by the term “directly” that no other component of the catheter (except for any potential joining means needed to join the flexible moving element to the surgical tool) is arranged between the surgical tool and the flexible moving element at the connection point.

According to an embodiment, the surgical tool may advantageously be indirectly connected to the flexible moving element. It is understood by the term "indirectly" that one or more components, preferably only one component, of the catheter (apart from any potential joining means needed to join the flexible moving element to the surgical tool) can be arranged between the surgical tool and the flexible moving element at the connection point.

The surgical tool can particularly be longitudinally movably, in particular slidably, arranged on the catheter shaft.

In particular, the surgical tool can be movably arranged directly on the catheter shaft (catheter shaft wall). When the surgical tool is an inflatable balloon, the inflatable balloon can for example have a form that partly or completely surrounds the catheter shaft. For example, the inflatable balloon may be formed as a donut, a hollow cylinder ora hollow barrel.

Alternatively, the surgical tool can be longitudinally movably, in particular slidably, arranged on the catheter shaft by being arranged on a further component of the catheter shaft.

In particular, the catheter preferably comprises a tool-receiving casing that is longitudinally movably arranged on the catheter shaft and connected to the flexible moving element, wherein the surgical tool is arranged on the tool-receiving casing. The tool-receiving casing is thus arranged between the flexible moving element and the surgical tool. In particular, the surgical tool is connected to the tool-receiving casing so that there is no relative movement between the surgical tool and the tool-receiving casing in the direction of the longitudinal axis of the toolreceiving casing. It is noted that the tool-receiving casing is advantageously fixed to the flexible moving element so that there is no such relative movement between the flexible moving element and the tool-receiving casing at their connection. The described arrangement of the tool-receiving casing, the catheter shaft and the flexible moving element with respect to each other is such that a movement of the flexible moving element is transmittable to the toolreceiving casing and in turn to the surgical tool arranged on, in particular fixed to, the toolreceiving casing. Thus, the surgical tool can be moved parallel to the longitudinal axis of the control shaft relative to the control shaft.

According to an embodiment of the present invention, the tool-receiving casing is preferably slidably arranged on the catheter shaft.

A longitudinal axis of the tool-receiving casing preferably corresponds to or is parallel to the longitudinal axis of the catheter shaft.

In an embodiment of the present invention, the tool-receiving casing is advantageously connected to the proximal piston and extends from a proximal portion to a distal portion of the catheter shaft such that the tool-receiving casing serves as a control handle for controlling the movement of the surgical tool. It is apparent that the proximal portion of the catheter shaft from which the tool-receiving casing extends is positioned outside the patient's body when the catheter is inserted in the patient’s body. In other words, a proximal portion including a proximal end of the tool-receiving casing is located outside the patient's body, while a distal portion including a distal end of the tool-receiving casing is located inside the patient's body when the catheter is used on a patient. It is pointed out that, though the tool-receiving casing also serves as the control handle, a force to the surgical tool is advantageously transmitted via the arrangement of the proximal piston, the distal piston and the flexible moving element, and not the tool-receiving casing, when the tool-receiving casing is being moved. Should not have been for said arrangement, the tool-receiving casing being itself flexible would otherwise tend to warp, when being pushed forward with respect to the catheter shaft.

The tool-receiving casing is advantageously arranged on the catheter shaft so that the toolreceiving casing partially or completely covers the distal shaft wall opening. Thus, the toolreceiving casing provides further support to the flexible moving element, and in particular to the part of the flexible moving element that is located in the distal shaft wall opening at a given position of the surgical tool. Further, the flexible moving element is advantageously connected to the tool-receiving casing via the distal shaft wall opening. The tool-receiving casing may preferably be formed such that it provides an at least partial circumferential support to the flexible moving element at a given cross-section. Thus, the flexible moving element may be arranged in the lumen and the distal shaft wall opening such that it is at least partially circumferentially supported by the catheter shaft wall so that a movement of the proximal piston in a direction from a proximal shaft end of the catheter shaft to a distal shaft end of the catheter shaft causes a movement of the surgical tool.

In general and particularly in the case of the tool-receiving casing partially covering the distal shaft wall opening, it can be of advantage if the flexibility of a distal portion of the flexible moving element is chosen such that the flexible moving element is adequately supported at its distal portion. In particular, the flexibility of the distal portion of the flexible moving element can be of lower flexibility than a middle portion of the flexible moving element.

Similarly to the surgical tool, the flexible moving element, the distal piston and the proximal piston, the tool-receiving casing also has two end positions. In the first end position, the toolreceiving casing is at its closest position with respect to the proximal shaft end of the catheter shaft, whereas in the second end position the tool-receiving casing is at its furthest position with respect to the proximal shaft end of the catheter shaft. As the surgical tool is fixed to the toolreceiving casing, the difference between the first end position and the second end position of the tool-receiving casing corresponds to the range of motion of the surgical tool parallel to the longitudinal axis of the catheter shaft, in other words the maximum distance that the surgical tool may cover during its movement parallel to the longitudinal axis of the catheter shaft.

The dimension of the distal shaft wall opening parallel to the longitudinal axis of the catheter shaft advantageously substantially corresponds to the maximum distance that the tool receiving casing and the surgical tool can be moved parallel to the direction of the longitudinal axis of the catheter shaft. The term "substantially” is used here to denote that a part of the flexible moving element connecting to the tool-receiving casing is arranged in the distal shaft wall opening. Thus, the distance that the tool-receiving casing can be moved is equal to the dimension of the distal shaft wall opening parallel to the longitudinal axis of the catheter shaft reduced by the dimension of the distal part of the flexible moving element arranged in the distal shaft wall opening in the direction parallel to the longitudinal axis of the catheter shaft.

According to an advantageous embodiment of the present invention, the tool-receiving casing may have the same outer shape with the (outer) shape of the catheter shaft and/or a

5 complementary inner shape to the (outer) shape of the catheter shaft.

Preferably, an outer and an inner shape of the tool-receiving casing are the same.

Preferably, the tool-receiving casing has a hollow cylindrical shape, in particular with a circular cross-section, i.e. the tool-receiving casing is in particular a hollow circular cylinder. However, the cross-section of the tool-receiving casing may also have another shape, e.g. the crosssection may be oval.

Most preferably, the tool-receiving casing is a hollow circular cylinder and the catheter shaft a circular cylinder. In this case, a fit between the tool-receiving casing and the catheter shaft is advantageously a clearance fit, which means that an inner diameter of the tool-receiving casing is larger than an outer diameter of the catheter shaft.

According to an alternative advantageous embodiment of the present invention, an inner shape of the tool-receiving casing and a(n) (outer) shape of the catheter shaft are different. This results in a smaller contact between the tool-receiving casing and the catheter shaft compared to the case where the tool-receiving casing and the catheter shaft have complementary shapes. With this configuration, friction losses during the movement of the tool-receiving casing and the catheter shaft relative to each other can be reduced. Preferably, the tool-receiving casing is formed as a hollow circular cylinder, while the catheter shaft comprises at least one frustoconical region.

According to an embodiment, the surgical tool is an inflatable balloon and the tool-receiving casing comprises a casing lumen that communicates with the inflatable balloon for inflating the balloon. In this case, the tool-receiving casing extends from a proximal portion to a distal portion of the catheter shaft so that fluid can be fed outside the patient’s body to the casing lumen. ‘Thus, the casing lumen extends from a proximal portion to a distal portion of the catheter shaft.

Apart from being longitudinally arranged on the catheter shaft, the tool-receiving casing is also preferably rotatably arranged on the catheter shaft. This allows the surgical tool to be not only movable parallel to but also rotatable around the longitudinal axis of the catheter shaft. This enhances the flexibility of the catheter in terms of placing the surgical tool at a desired position and with a desired orientation within the body of the patient. Additionally, this arrangement of the tool-receiving casing makes it easier for the tool-receiving casing and thus the surgical tool to be moved through narrow passages in the patient’s body. When the surgical tool is an inflatable balloon and the balloon is inflated and anchored to a body lumen, the rotation of the tool-receiving casing and thus of the balloon is transformed to a rotation of the catheter shaft, which can thus be forwarded more easily through a narrow passage of the lumen. In order for the tool-receiving casing to be rotated, the flexible element is preferably rotatably arranged inside the flexible element receiving lumen. In view of this, the distal shaft wall opening is formed such that a rotation of the flexible element around the longitudinal axis of the flexible element is possible.

Most preferably, the tool-receiving casing is rotatably arranged on the catheter shaft such that a rotational range of the tool-receiving casing and thus of the surgical tool comprises (up to) 180 degrees. Accordingly, the flexible element preferably has a rotational range of (up to) 180 degrees.

In particular, the tool-receiving casing and thus the surgical tool can be configured to rotate 90 degrees in both directions around the longitudinal axis of the tool-receiving casing, wherein the longitudinal axis of the tool-receiving casing lies in a symmetry plane of the catheter shaft. Accordingly, the flexible element can preferably be configured to rotate (up to) 90 degrees in both directions around its longitudinal axis, wherein the longitudinal axis of the flexible element lies in a symmetry plane of the catheter shaft. The “0 degrees” -position of the tool-receiving casing or of the flexible element corresponds to the symmetry plane of the catheter shaft. To this end, it is preferred that the distal shaft wall opening is a formed as a recess that goes through the catheter shaft wall in a transverse axis of the catheter shaft. The transverse axis is vertical to the longitudinal axis of the catheter shaft. When the catheter shaft: is formed as a circular cylinder, the transverse axis can in particular be a radial axis.

According to an advantageous embodiment of the present invention, the tool -receiving casing and the catheter shaft are threadably engaged with each other. Thus, the tool-receiving casing can be moved in the direction of the longitudinal axis of the catheter shaft in a controllable way due to the threaded engagement of the tool-receiving casing and the catheter shaft with each other. More specifically, the tool-receiving casing is internally threaded, while the catheter shaft is externally threaded. Here, the internal (inner) threads of the tool-receiving casing are in engagement with the external (outer) threads of the catheter shaft. In the case of the toolreceiving casing being formed such that it also acts as a control handle, a distal portion of the tool-receiving casing is preferably threaded.

In particular, the internal threads of the tool-receiving casing and the external threads of the catheter shaft are formed such that a movement of the control handle in the direction of its longitudinal axis causes a rotation of the tool-receiving casing around the longitudinal axis of the catheter shaft combined with a movement of the tool-receiving casing in the direction of the longitudinal axis of the catheter shaft, i.e. a helical movement of the tool-receiving casing. This configuration has the advantage that the force with which the control handle is being moved in the direction of its longitudinal axis is translated into a helical movement of the tool-receiving casing. It is understood that, when the threaded tool-receiving casing is formed such that it also acts as a control handle, a movement of the tool-receiving casing in the direction of the longitudinal axis of the catheter shaft by applying a corresponding force at its proximal end or area will eventually force the user of the catheter to rotate his/her hand together with the toolreceiving casing.

The catheter shaft can be left-handed threaded or right-handed threaded. Accordingly, the toolreceiving casing can be left-handed threaded or right-handed threaded.

It is also possible that the catheter shaft comprises at least one region with a left-handed thread and at least one region with a right-handed thread. The tool-receiving casing is then formed accordingly. This configuration is advantageous as the surgical tool can be moved through narrow passages of different morphologies by turning the surgical tool counterclockwise and clockwise so that it goes round/avoids potential obstacles in the path (e.g. plaque in a blood vessel, protrusion due to the anatomy of the path). When the surgical tool is an inflatable balloon and the balloon is inflated and anchored to a body lumen, the rotation of the toolreceiving casing and thus of the balloon counterclockwise and clockwise is transformed to a corresponding rotation of the catheter shaft, what allows the catheter shaft to be squeezed and forwarded through a narrow passage of the lumen.

Preferably, at least a portion of the tool-receiving casing has an open cross-section. This means that the tool-receiving casing may preferably have an open cross-section over a portion of or over its whole length. This is advantageous in particular when the surgical tool should be moved through narrow passages and tortuous lumens in the patient’s body.

Advantageously, the open cross-section is such that the tool-receiving casing preferably substantially surrounds the catheter shaft. "Substantially" means in particularly that at least 60%, preferably at least 70%, more preferably at least 80%, of a corresponding cross-section of the catheter shaft is surrounded by the corresponding open cross-section of the tool-receiving casing. Especially when the open cross-section of the tool-receiving casing has a circular or oval form, “substantially" can additionally or alternatively mean that the cross-section may extend over at least 220 degrees, more preferably over at least 260 degrees, even more preferably over at least 290 degrees. This bears the advantage that the tool -receiving casing cannot be demounted from the catheter shaft even if the catheter shaft is being forwarded through very narrow passages and extreme tortuous lumens of the patient's body. Alternatively, the tool-receiving casing may have a closed cross-section over its whole length.

Preferably, the catheter comprises a control means for controlling the movement of the surgical tool. To this end, the control means is connected to the proximal piston. It is apparent that the control means is located outside the patient's body, when the catheter is inserted in the patient, so that the doctor can manipulate the control means.

The control means may preferably comprise a control element that can be formed as a stiff or as a flexible element.

In the case of the control element being formed as a stiff control element, the control element and the proximal piston may be connected with each other or formed as a single piece. In particular, the stiff control element can be formed as a shaft. Advantageously, the stiff control element and the proximal piston may be formed as a plunger like the one used in syringes. In the framework of the present invention, the term “stiff” advantageously means that the control element is not bendable by its own weight when fixed at at least one of its ends. In other words, the term “stiff” means that the control element can support/carry/bear its own weight without being bent.

In particular, the stiff control element is connected to a distal end of the proximal piston. Further, the stiff control element is advantageously movable inside the lumen between the first end position and a second end position. The first end position and a second end position of the stiff control element correspond to the first end position and the second end position of the surgical tool, respectively. In particular, the stiff control element is partially arranged inside the lumen throughout its complete movement between its first end position and second end position.

In the case of the control element being formed as a flexible control element, the control element is connected to the proximal piston, in particular to a distal end of the proximal piston, and is in such a way that the flexible control element is at least partially circumferentially supported by the catheter shaft wall so that the proximal piston is movable towards the distal shaft end of the catheter shaft by the flexible control element. In other words, the control element is arranged in such a way that the flexible control element is at least partially circumferentially supported by the catheter shaft wall so that a force applied on the control element in a direction from a proximal shaft end of the catheter shaft to a distal shaft end of the catheter shaft causes a movement of the proximal piston.

It is noted that features and details described in view of the flexible moving element, in particular its size, shape and arrangement in the lumen, also apply, separately or in combination with each other, to the flexible control element. Advantageously, the flexible moving element and the flexible control element may be identical to each other. The control means may preferably further comprise a control handle connected to the control element, in particular to a proximal end and/or portion of the control element. In this case, the doctor may manipulate the control handle for controlling the movement of the surgical tool. To this end, the control handle may be ergonomically formed.

According to an advantageous embodiment, the control handle is formed as a casing that is longitudinally movably, in particular slidably, arranged on the catheter shaft. The casing can also be described as “control casing" in the framework of the present invention.

Each of the components of the control means has a first end position and a second position, which correspond to the first end position and the second end position of the surgical tool, respectively. In the first end position, the respective component of the control means is at its furthest position from the distal shaft end, while in the second end position the respective component is at its closest position to the distal shaft end.

The control casing is advantageously arranged on the catheter shaft so that the control casing partially or completely covers the proximal shaft wall opening. Thus, the control casing provides further support to the control element, when being formed as a flexible control, and in particular to the part of the flexible control element that is located in the proximal shaft wall opening at a given position of the surgical tool. Further, the control element is advantageously connected to the control casing via the proximal shaft wall opening. The control casing may preferably be formed such that it provides an at least partial circumferential support to the flexible control element at a given cross-section. Thus, the at flexible control element may be arranged in the lumen and the proximal shaft wall opening such that it is at least partially circumferentially supported by the catheter shaft wall so that the proximal piston is movable towards the distal shaft end of the catheter shaft by the flexible control element.

A dimension of the proximal shaft wall opening parallel to the longitudinal axis of the catheter shaft advantageously substantially corresponds to the distance that the control casing can be moved parallel to the direction of the longitudinal axis of the catheter shaft. The term “substantially” is used here to denote that a part of the control element connected to the casing is arranged in the proximal shaft wall opening. Thus, the distance that casing can be moved is equal to the dimension of the proximal shaft wall opening parallel to the longitudinal axis of the catheter shaft reduced by the dimension of the proximal part of the control element arranged in the proximal shaft wall opening in the direction parallel to the longitudinal axis of the catheter shaft.

In general and particularly in the case of the control casing partially covering the proximal shaft wall opening, it can be of advantage if the flexibility of a proximal portion of the control element, when being formed as a flexible control element, is chosen such that the control element is adequately supported at its proximal portion. In particular, the flexibility of the proximal portion of the flexible moving element can be of lower flexibility than a middle portion of the flexible moving element.

In an advantageous manner, the control casing may have the same outer shape with the (outer) shape of the catheter shaft and/or a complementary inner shape to the (outer) shape of the catheter shaft. Preferably, an outer and an inner shape of the control casing are the same.

Preferably, the control casing has a hollow cylindrical shape, in particular with a circular crosssection, i.e. the control casing is in particular a hollow circular cylinder. However, the crosssection of the control casing may also have another shape, e.g. its cross-section may be oval.

According to a preferred embodiment of the present invention, the control casing is a hollow circular cylinder and the catheter shaft a circular cylinder. In this case, a fit between the control casing and the catheter shaft is advantageously a clearance fit, which means that an inner diameter of the casing is larger than an outer diameter of the catheter shaft.

According to an alternative advantageous embodiment of the present invention, an inner shape of the control casing and a(n) (outer) shape of the catheter shaft are different. This results in a smaller contact between the control casing and the catheter shaft compared to the case where the inner shape of the control casing and the (outer) shape of the catheter shaft are the same. Thus, friction losses during the relative movement between the control casing and the catheter shaft can be reduced. Preferably, the control casing is formed as a hollow circular cylinder, while the catheter shaft comprises at least one frustoconical region.

The flexible moving element and/or the flexible control element is/are preferably formed as a wire. The term “wire" may also comprise a cable or any other flexible rod-shaped element. In another advantageous embodiment, the flexible moving element and/or the flexible control element is/are formed as a sheet. The sheet can in particular be curved. However, the flexible moving element and/or the flexible control element can be any element that can be bent, so that the catheter can be bent as a unit, when being forwarded through lumens and cavities of hollow organs of a patient’s body.

The flexible moving element and/or the control element may be made for example from metal, plastic or a composite material.

According to a preferred embodiment of the present invention, the surgical tool of the catheter is an inflatable balloon. With the help of the inflatable balloon, the suggested catheter acquires greater pushability, since the needed propulsive force for moving the catheter shaft forward can be applied close to its tip. The term “pushability’' means the degree in which the force transmitted from a proximal shaft end of the catheter is translated into movement of a catheter’s distal end (catheter tip), which depends on the transmission of the force along the body of the catheter, is understood. In other words, the term "pushability" means the ease of advancing the catheter inside a lumen, e.g. a blood vessel, and is indicative of the amount of force the distal tip of the catheter shaft sees when a known force is being applied to the proximal shaft end of the catheter shaft. With respect to crossability, i.e. the ability to navigate the tip of the catheter shaft across narrow restrictions in the vasculature, the suggested catheter can be moved through a significant stenosis by using the propulsive force applied by the moving balloon by pushing the tip of the catheter shaft with greater force. When a guidewire is further provided in the catheter, the catheter can offer maximal backup support to the guidewire and in addition, the greatest possible pushability, crossability and trackability over the guidewire in narrowed or blocked lumens and passages of the patient's body. More specifically, the catheter can provide backup support to the guidewire in the effort to move it through anatomically difficult areas of lumens of the human body, while - at the same time - it can be accurately repositioned, keeping the balloon inflated and anchored within the lumen. In particular, the trackability of the catheter over the guidewire is high, since once again the propulsive force of the balloon moving close to the tip of the catheter shaft is much greater. This is specifically advantageous in tortuous lumens, where the crossing of the catheter is hindered due to the multiplication of the friction between the catheter shaft and the lumen walls as well as between the catheter shaft and the guidewire caused by the existing tortuosity.

According to an embodiment of the present invention, the surgical tool is an inflatable balloon and the flexible moving element, the distal piston and the proximal piston are hollow. The flexible moving element is in fluid communication with the balloon and a conduit, the conduit being arranged between the distal piston and the proximal piston. Thus, the balloon can be inflated by a fluid (gar or liquid) provided to the balloon through the proximal piston, the conduit, the distal piston and the flexible moving element. In particular, the flexible moving element comprises a flexible moving element fluid channel. The distal piston and the proximal piston each comprise a through opening. The conduit can in particular be a tube.

When the catheter comprises a tool-receiving casing, a through opening is preferably formed in the tool-receiving casing. The through opening of the tool-receiving casing can be part of fluid path for providing fluid to the balloon and/or be used as a connection area for the flexible moving element.

Accordingly, when the catheter comprises a control means as described above, the control means may be hollow and in fluid communication with the conduit. Thus, a fluid source can be connected to the control means for providing fluid through the control means to the conduit and from there to flexible moving element and eventually to the balloon. In particular, the control means comprises a control means fluid channel.

The through opening of the distal piston can be used as part of the fluid path for providing fluid to the balloon and/or as a connection area for the conduit at its proximal portion and/or for the flexible moving element at its distal portion. Accordingly, the through opening of the proximal piston can be used as a part of the fluid path for providing fluid to the balloon and/or as a connection area for the conduit at its proximal portion and/or for the control element at its distal portion.

The control means fluid channel may comprise a control element fluid channel formed in the control element. In case the control means further comprises a control handle, a through opening is preferably formed in the control handle. The through opening of the control handle can be part of the control means fluid channel or be used as a connection area for the control element.

For example, air, helium, water or a water solution preferably containing a contrast agent can be used for inflating the balloon.

In order to assist the movement of the distal piston in a direction from the distal shaft end of the catheter shaft to the proximal shaft end of the catheter shaft, it can be of advantage if the distal piston and the proximal piston are connected to each other by a connecting means. This can be in particular advantageous in a catheter, in which the negative pressure that builds up due to the movement of the proximal piston in the direction from the distal shaft end to the proximal shaft end of the catheter shaft is not sufficient for controllably moving the distal piston in the same direction with the proximal piston.

The connecting means is preferably configured to exert/transmit only a pulling force. In other words, the connecting means connecting the distal piston with the proximal piston can preferably only be loaded with a tensile load. Thus, the connecting means can only pull the distal piston towards the proximal shaft end of the catheter shaft, when the proximal piston is pulled towards the proximal shaft end of the catheter shaft. The connecting means can preferably be formed as a wire, a thread or the like. However, it is also possible that the connecting means is configured such that it can additionally exert/transmit a pushing force/pressure load. In other words, it is also possible that the connecting means is configured such that it can additionally be loaded with a pressure load. In this case, a pushing movement of the proximal piston can be transferred to distal piston via the incompressible fluid and the connecting means. It is apparent that the connecting means is located in the space between the distal and proximal piston filled with the incompressible fluid.

Said connecting means is advantageously provided in catheters, in which there is no need to deliver fluid to the surgical tool. The reason is that in those catheters there is no conduit between the distal piston and the proximal piston as described above, which would be in general able to pull or assist with pulling the distal piston towards the proximal shaft end of the catheter shaft, when the proximal piston is pulled towards the proximal end of the catheter shaft. Nevertheless, the connecting means can be provided even in those catheters in order not to overload the conduit, what could potentially lead to a disconnection of the conduit from the pistons.

In an embodiment of the present invention, the flexible moving element and the flexible control element may be made as a single flexible element being connected to the distal piston and the proximal piston. In this case, the distal piston and the proximal piston are hollow, i.e. each comprise a through opening, so that the single flexible element can go through the pistons. In this case, the single flexible element is partially arranged in the space between the pistons filled with the incompressible fluid. The incompressible fluid surrounding the single flexible element provides a support for the single flexible element in the space between the distal piston and the proximal piston so that a movement of the proximal piston is transmittable to the distal piston via the single flexible element and the incompressible fluid. It may be advantageous if the lumen portion in which the distal piston and the proximal piston are movably arranged has a larger cross-section than the rest of the lumen, e.g. than the lumen portion in which the flexible moving element and/or the control element is/are arranged. Thus, a higher amount of incompressible fluid can be provided in the space between the distal piston and the proximal piston. Thus, due to the larger amount of incompressible fluid surrounding the portion of the single flexible element arranged in the space between the distal piston and the proximal piston, a force applied to the proximal piston can more uniformly be distributed over the single flexible element and the incompressible fluid.

Regardless of the embodiment, in which the flexible moving element and the flexible control element are made as a single flexible element, the lumen may in general have a region which has a cross-section larger than the rest of the lumen. Preferably, the region with the larger cross-section compared to the rest of the lumen is the region in which the distal piston and the proximal piston are arranged. This means that in this case the distal piston and the proximal piston have piston areas (piston surface areas) equal to the area of the larger cross-section of the lumen.

Alternatively, the lumen may have the same cross-section over its whole length. Advantageously, the distal piston and the proximal piston have the same shape.

The distal piston and the proximal piston may also have the same piston area (piston surface area). A distance between the distal and the proximal piston remains the same throughout the whole range of motion of the pistons.

However, it is also possible that the distal piston and the proximal piston have different piston areas. For example, the distal piston may have a larger piston area than the proximal piston, if a multiplication of the force applied to the proximal piston by the doctor is desired at the distal area of the catheter shaft. This could be particularly beneficial in case the catheter is intended to be used for passing through extremely narrow passages in the patient’s body, e.g. blocked blood vessels. Of course, the distal piston can have a smaller piston area than the proximal piston, when a multiplication of the movement of the proximal piston, i.e. when a larger displacement of the surgical tool than the movement of the proximal piston, is desired. If the pistons have different piston areas, the lumen should be formed accordingly in order to receive the pistons.

It is further understood that the distal piston and proximal piston are formed such that no leakage of the incompressible fluid can occur.

In an embodiment of the present invention, the already described lumen is a first lumen, wherein the catheter shaft comprises a second lumen and a third lumen, each defined by the catheter shaft wall. The control means may comprise a further (flexible or stiff) control element partially arranged in the second lumen and connected to the proximal piston. In addition, the catheter comprises a further flexible moving element partially arranged in the third lumen and connected to the distal piston. It is noted that the second lumen and the third lumen are defined such that they each communicate with the first lumen, in particular the lumen portion of the first lumen, in which the distal piston and the proximal piston are arranged.

As already mentioned above, the surgical tool of the catheter may be an inflatable balloon. Preferably, the inflatable balloon can be formed such that, when it is in its inflated state, it allows body fluids of the patient to pass by, preferably more easily in one direction than in another direction, most preferably only in one direction. This is in particular advantageous when the catheter is used as a nasogastric catheter and placed inside the oesophagus of the patient. In order for the catheter to be stabilized at a desired position, the balloon has to be inflated so that it is anchored to the oesophagus. The balloon being formed according to this advantageous embodiment of the present invention would thus allow saliva pass by the balloon and not be accumulated in the oesophagus, while it would preferably hinder the reflux of gastric contents to the oesophagus. The balloon preferably comprises a proximal balloon end, a distal balloon end, and at least one channel extending from the proximal balloon end to the distal balloon end for allowing a flow of fluid therethrough in the inflated state of the balloon.

According to an advantageous embodiment, the at least one channel is formed as a recess in a circumferential area of the balloon. In other words, an outer dimension of a first region of the balloon at a given cross-section is smaller than an outer dimension of a second region of the balloon at the given (same) cross-section. The second region is the region through which the balloon is configured to be in contact with the wall of a body cavity, passage, lumen etc., when the balloon is placed and inflated therein.

The balloon can particularly comprise a main region and at least one secondary region, which protrudes from the main region in the inflated state of the balloon. Thus, the balloon can be anchored to the wall of a body cavity, passage, lumen etc. only via its secondary region(s), while the space(s) between the main region and the secondary region or the secondary regions will allow body fluids to flow along the balloon. For example, the balloon may have four secondary regions, which protrude from the main region and form the shape of a cross, when the balloon is inflated.

According to an alternative advantageous embodiment, the at least one channel extends through an inner space of the balloon.

Regardless of whether the channel is formed as a recess or if extends through an inner space of the balloon, the channel may preferably be formed such that fluid can flow substantially in one direction or only in one direction through the channel.

To this end, a first channel cross-section of the at least one channel is preferably larger than a second channel cross-section of the at least one channel. In particular, the first channel crosssection is arranged at a first channel end, more particularly a proximal channel end, and the second channel cross-section is arranged at a second channel end, more particularly a distal channel end. Preferably, the at least one channel has a tapered form between the first channel cross-section and the second channel cross-section. Additionally or alternatively thereto, a oneway valve is arranged at the first second cross-section or the second channel cross-section.

The surgical tool can also be formed as a cutting device, such as a Fallopian tube scraping wire (curretage wire for uterine curettage) or a blade, e.g. an atherectomy blade, a stent or any other tool that can be used in a surgical procedure, in which a catheter is used, and that can be connected directly or indirectly to the flexible element. In the framework of the present invention, the surgical tool may also comprise materials (e.g. a creme, a medical substance) that need to be unloaded within a lumen or cavity of a hollow organ of the human or animal body. Preferably, the catheter shaft further comprises at least one further lumen for receiving a guidewire and/or passing a fluid therethrough, e.g. for delivering a fluid to a site of interest in the patient’s body and/or removing body or other fluids from the patient's body. The at least one further lumen can also be characterized as at least one guidewire and/or fluid passing lumen. It is also possible that the at least one further lumen comprises at least one guidewire lumen and at least one fluid passing lumen as separate lumens.

The at least one guidewire and/or fluid passing lumen advantageously extends over a whole length of the catheter shaft. In other words, a proximal end and a distal end of the at least one guidewire and/or fluid passing lumen correspond to a proximal end and a distal shaft end of the catheter shaft, respectively. Alternatively, the at least one guidewire and/or fluid passing lumen may extend a partial length of the catheter shaft.

The lumen(s) and/or the at least one guidewire and/or fluid passing lumen are preferably parallel to each other.

Further, the lumen(s) and/or the at least one guidewire and/or fluid passing lumen may have the same or different shapes and/or sizes.

Preferably, the lumen(s) and/or the at least one guidewire and/or fluid passing lumen each have a cylindrical shape, in particular with a circular cross-section, i.e. the lumen(s) and/or the at least one guidewire and/or fluid passing lumen is/are in particular a circular cylinder. However, the cross-section of the lumen(s) and/or the at least one guidewire and/or fluid passing lumen may have another shape, e.g. the cross-section may be oval.

The catheter may also use a guidewire arranged in the at least one guidewire and/or fluid passing lumen of the catheter shaft. The guidewire can advantageously be used as a guide for inserting a further catheter, after the guidewire has reached a site of interest inside the human or animal body by using the catheter of the present invention and the catheter of the present invention has been removed from the body of the patient. An assembly of the catheter with the guidewire can in particular be characterized as a catheter assembly.

Preferably, the flexibility of the flexible moving element and/or the flexible control element is/are the same with the flexibility of the guidewire.

The catheter shaft preferably comprises a tip with an opening. The tip of the catheter corresponds to a distal end region of the catheter shaft and comprises an opening preferably corresponding to the distal shaft end of the catheter shaft. Further, the catheter shaft comprises a main part, to which the tip is connected. The tip and a portion of the main part of the catheter shaft are located inside the patient's body when the catheter is used, whereas the rest of the main part of the catheter shaft is located outside the patient’s body. The tip is advantageously tapered.

The catheter shaft may preferably have an internal and/or an external lining of lubricant on an inner surface of the catheter shaft wall defining the lumen(s) and on the outer surface of the catheter shaft wall, respectively. Preferably, the tool receiving casing and/or the casing of the control means has/have an internal lining of lubricant. The lubricant can for example be Teflon. Thus, a friction between the flexible moving element(s) and/or the flexible control element(s) and the corresponding lumen(s) and/or between the pistons and the lumen and/or between the tool-receiving casing and the catheter shaft and/or between the casing of the control means and the catheter shaft can be reduced.

In the framework of the present invention, the longitudinal axis of the catheter shaft advantageously corresponds to a longitudinal axis of the catheter. Further, the proximal end and the distal shaft end of the catheter shaft advantageously correspond to a distal end and a proximal end of the catheter, respectively.

In the framework of the present invention, the term “proximal shaft end” means the end of the catheter shaft that is outside of the patient’s body and the term "distal shaft end” the end of the catheter shaft that is inside the patient’s body when the catheter is inserted into the patient. The term “proximal” describing a feature of the catheter means that said feature is closer to the proximal shaft end or the doctor than to the distal shaft end, when the catheter is used on a patient or held with the appropriate orientation corresponding to its intended use, i.e. the insertion into the patient. On the other hand, the term “distal” means that the feature of the catheter is closer to the distal shaft end than to the doctor or the proximal shaft end. For example, the term “proximal area/region/portion” of a component of the catheter or the catheter itself means in particular that this area/region/portion is located closer to the proximal shaft end or the doctor.

It is noted that the formulation “defined by the catheter shaft wall" referring to the lumen of the catheter shaft described above means that the lumen corresponds to a hollow space of the catheter shaft restricted/limited/bounded/surrounded by the catheter shaft wall, in particular an inner portion, preferably an inner surface, of the catheter shaft wall.

The catheter may also comprise at least one further surgical tool that is fixed on the catheter shaft (at least one non-mobiie surgical tool) and/or at least one further surgical tool that is movable relative to the catheter shaft (at least one further mobile surgical tool). The features and explanations referring to the design of the previously described surgical tool and its movable arrangement in the catheter advantageously also refer to the at least one further mobile surgical tool. In other words, the catheter of the present invention may comprise a plurality of surgical tools, from which at least one is a movable surgical tool. A catheter having a plurality of surgical tools comprises in its simplest configuration a first surgical tool and a second surgical tool. Here, the previously described surgical tool corresponds to the first surgical tool. The previously described lumen, flexible moving element, distal piston and proximal piston are a first lumen, a first flexible moving element, a first distal piston and a first proximal piston, respectively. The first surgical tool and the second surgical tool are movable relative to each other. The term “plurality of surgical tools" means “two or more surgical tools".

According to a preferred embodiment, the second surgical tool is fixed on the surgical tool.

According to an alternative preferred embodiment, the second surgical tool is movable independently from the first surgical tool. In this embodiment, the catheter shaft comprises a second lumen defined by the catheter shaft wall, a second flexible moving element, a second surgical tool connected to the second flexible moving element, a second distal piston and a second proximal piston. The second distal piston and the second proximal piston are arranged in the second lumen and a space between the second distal piston and the proximal piston is filled with an incompressible fluid. The second distal piston is connected to the second flexible moving element. The second flexible moving element is arranged in the catheter shaft in such a . way that the second flexible moving element is at least partially circumferentially supported by the catheter shaft wall so that a movement of the second proximal piston in a direction from a proximal shaft end of the catheter shaft to a distal shaft end of the catheter shaft causes a movement of the second surgical tool.

The catheter may preferably comprise a third surgical tool that is fixed on the catheter shaft.

The present invention further refers to a method of use of the described catheter in a surgical procedure. The method comprises the step of providing a previously described catheter.

These and further details, advantages and features of the present invention will be described based on embodiments of the invention and by taking reference to the accompanying figures. It is shown in: figure 1 a simplified perspective view of a catheter according to a first embodiment of the present invention, figure 2 a simplified perspective view of a catheter according to a second embodiment of the present invention, figure 3 a simplified perspective view of a part of the catheter according to the second embodiment, figure 4 a simplified perspective view of a part of the catheter according to the second embodiment of the present invention, figure 5 a simplified perspective view of a part of a catheter according to a third embodiment of the present invention, figure 6 a simplified perspective view of a part of the catheter according to the fourth embodiment of the present invention, figure 7 a simplified perspective view of a part of the catheter of figure 6, figure 8 a simplified perspective view of a catheter according to a fifth embodiment of the present invention, figure 9 a simplified perspective view of a part of the catheter of figure 8, figure 10 a simplified perspective view of a part of a catheter according to a sixth embodiment of the present invention, figure 11 a simplified perspective view of a part of the catheter of figure 10, figure 12 a simplified perspective view of a part of a catheter according to a seventh embodiment of the present invention, figure 13 a simplified perspective view of a part of the catheter according to an eighth embodiment of the present invention, figure 14 a cross-section of a part of a catheter according to a ninth embodiment of the present invention, figure 15 a simplified side view of a catheter according to present invention in a first and a second state inside a body lumen, figure 16 a simplified side view of the catheter of figure 15 in a third and a fourth state inside the body lumen, and figure 17 a simplified perspective view of an example of a catheter.

In the following, embodiments and uses of the present invention are presented in detail by taking reference to accompanying figures 1 to 16. Identical or equivalent features and features which act identically or equivalently are denoted with the same reference signs. For the sake of conciseness, a detailed description of the elements and components is not repeated in each case of their occurrence. It is also noted that the length of the catheter is not necessarily drawn to scale for illustrative reasons. Figure 1 shows a perspective view of a catheter 1 according to a first embodiment of the present invention.

As can be seen from figure 1 , the catheter 1 comprises a catheter shaft 2, a flexible moving element 3, a surgical tool 5 connected to the flexible moving element 3, a distal piston 8, a proximal piston 9 and a control means 7 for controlling the surgical tool 5. In the present embodiment, the surgical tool 5 is an inflatable balloon 50.

The catheter shaft 2 comprises a main part 200 and a tip 201 attached to the main part 200 and extends in the direction of a longitudinal axis 500 between a distal shaft end 28 and a proximal shaft end 29.

Further, the catheter shaft 2 comprises a lumen 21 defined by a catheter shaft wall 24 and a distal shaft wall opening 25, which is formed in a distal circumferential area of the catheter shaft 2 and communicates with the lumen 21. The lumen 21 extends from the proximal end 29 of the catheter shaft 2 to the distal shaft wall opening 25 and has a constant cross-section over its length. The distal shaft wall opening 25 is more particularly formed as a through recess in the catheter shaft wall 24 in a direction of a transverse axis 502 of the catheter shaft 2.

The distal piston 8 and the proximal piston 9 have the same piston area and are arranged in the lumen 21. However, it is also possible that the distal piston 8 and the proximal piston 9 have different piston areas. In this case, the portion of the lumen 21 , which the distal piston 8 and the proximal piston 9 are movably arranged, should be accordingly formed.

The distal piston 8 is connected to the flexible moving element 3, in particular to a proximal end 311 of the flexible moving element 3. A distal end 312 of the flexible moving element 3 is directly connected to the balloon 50. A space 11 between the distal piston 8 and the proximal piston 9 is filled with an incompressible fluid, so that a movement of the proximal piston 9 can be transferred to the distal piston 8 via the incompressible fluid.

When looking further into the structure of the catheter 1 , it can be seen that the flexible moving element 3 is formed as a wire 31. The wire 31 is specifically formed as a hollow cylinder and comprises a flexible moving element fluid channel 310, which is in fluid communication with the inflatable balloon 50.

Figure 1 shows the balloon 50 in its inflated state and protruding out of the catheter shaft 2. When the balloon 50 is undeployed, i.e. deflated, the balloon 50 can be completely located inside the lumen 21 of the catheter shaft 2. Alternatively, the balloon 50 can be situated in its deflated state partially inside the lumen 21 and partially inside the distal shaft wall opening 25, or completely inside the distal shaft wall opening 25. It is, however, also possible that the balloon 50 is directly slidably arranged on the catheter shaft 2, in particular the catheter shaft wall 24. For example, the balloon 50 can be formed such that it completely surrounds the catheter shaft 2.

The wire 31 is extractabiy arranged in the lumen 21 between a first end position and a second end position. In particular, the wire 31 is arranged in the catheter shaft 2 in such a way that the wire 31 is circumferentially supported by the catheter shaft wall 24 so that a movement of the proximal piston 9 in a direction from the proximal shaft end 29 to the distal shaft end 28 of the catheter shaft 2 causes a movement of the surgical tool 5. In other words, the wire 31 is configured such that a movement of the distal piston 8 caused by a movement of the proximal piston 9 in the direction towards the distal shaft end 28 of the catheter shaft 2 causes the wire 31 to move in a way that the balloon 50 is also movable. This is made possible, as due to the circumferential/lateral support provided by the catheter shaft wall 24 the rather flexible wire 31 functions as a stiffer element, when a pushing force towards the distal shaft end 28 of the catheter shaft 2 is applied to it. However, the wire 31 remains capable of being bent together with the catheter shaft 2, when the catheter 1 is steered through a curved pathway in the body of a patient.

To this end, an outer diameter of the wire 31 is preferably at least 80%, more preferably at least 85%, even more preferably at least 90%, even more preferably at least 95%, most preferably substantially 100%, of a diameter of the lumen 21. Advantageously, a fit between the wire 31 and the lumen 21 is a clearance fit.

Particularly, the wire 31 is longitudinally movable, specifically slidable, between the first end position and the second end position.

In the first end position, the wire 31 is totally pulled back towards the proximal shaft end 29 of the catheter shaft 2, whereas in the second end position the wire 31 is totally moved forward towards the distal shaft end 28 of the catheter shaft 2.

A movement of the wire 31 towards the distal shaft end 28 of the catheter shaft 2 results in a movement of the balloon 50 towards the distal shaft end 28 and eventually out of the catheter shaft 2 through the distal shaft wall opening 25. Figure 1 shows the second end position of the wire 31. Accordingly, a movement of the wire 31 towards the proximal end 28 results in a movement of the balloon 50 towards the proximal shaft end 29.

For the purpose of controlling the movement of the balloon 50, the catheter 1 further comprises a control means 7.

More particularly, the control means 7 comprises a control element 71 that is connected to the proximal piston 9. The control element 71 may be formed as a stiff control element, in particular a shaft. In order to cause a movement of the balloon 50, the doctor has to push or pull the control element 71.

A pushing movement of the control element 71 denoted by arrow 701 is transferred to the proximal piston 9, from the proximal piston 9 to the distal piston 8 via the incompressible fluid and from the distal piston 8 via the wire 31 to the balloon 50.

On the other hand, a pulling movement of the control element 71 denoted by arrow 702 causes a pulling movement of the proximal piston 9. The movement of the proximal piston 9 towards the proximal shaft end 29 of the catheter shaft 2 causes a build-up of negative pressure in the space 11 between the distal piston 8 and the proximal piston 9, which results in a movement of the distal piston 8 towards the proximal shaft end 29.

For the purpose of inflating the balloon 50, the flexible moving element fluid channel 310 is in fluid communication with a control means fluid channel 75 of the control means 7 by a conduit 10. In particular, the control means fluid channel 75 comprises a control element fluid channel 711 formed in the control element 71 . Thus, fluid can be delivered to the balloon 50 through the control element fluid channel 711, the conduit 10 and the flexible moving element channel 310. To this end, the distal piston 8 and the proximal piston 9 are hollow. In the present embodiment, the conduit 10 can be connected with the distal piston 8 and the proximal piston 9 at their corresponding hollow parts.

As an alternative to the stiff structure of the control element 71 , it is also possible that the control element 71 is made as a flexible control element. For example, the control element 71 can be formed as a cylindrical hollow wire like the flexible moving element 3. In this case, the flexible control element 71 is arranged in the lumen 21 in such a way that the control element 71 is circumferentially supported by the catheter shaft wall 24 so that the proximal piston 9 is movable by the control element 71. To this end, an outer diameter of the control element 71 is preferably at least 80%, more preferably at least 85%, even more preferably at least 90%, even more preferably at least 95%, most preferably substantially 100%, of a diameter of the lumen 21. Advantageously, a fit between the control element 71 and the lumen 21 is a clearance fit. Particularly, the control element 71 is longitudinally movable, specifically slidable, between a first end position and a second end position. In the first end position, the control element 71 is at its furthest position from the distal shaft end 28 of the catheter shaft 2 and preferably partially arranged in the lumen 21 , while in the second end position the control element 71 is at its closest position to the distal shaft end 28 and preferably partially arranged in the lumen 21 . It is noted that a distal area of the control element 71 , in particular having a length corresponding to the length of the control element 71 that is arranged outside of the lumen 21 in the first end position of the control element 71 , may be stiff or provided with a handle. Thereby, a manipulation of the flexible control element 71 by a doctor can be made easier.

The tip 201 and a portion of the main part 200 of the catheter shaft 2 including the distal shaft wall opening 25 are located inside the patient's body during use of the catheter 1, whereas the rest of the main part 200 of the catheter shaft 2 is located outside the patient’s body. Further, the proximal piston 9 is preferably located outside the patient's body, when the catheter 1 is inserted in the patient. The control element 71 is located partially outside the patient’s body, when the catheter 1 is inserted in the patient, so that the movement of the proximal piston 9 can be controlled and thus that of the inflatable balloon 50.

The catheter shaft 2 also comprises a further lumen 22, which is defined by the catheter shaft wall 24 and in which a guidewire 100 may be arranged. The further lumen 22 is in particular parallel to the lumen 21 and extends in a direction parallel to the longitudinal axis 500 of the catheter shaft 2. Both lumens 21 , 22 are formed as circular cylinders.

The catheter 1 of the present embodiment can for example be used in a nasogastric application. In such an application, a catheter must usually be placed inside the stomach of the patient and kept to position such that it cannot be accidentally be withdrawn from the patient’s body. Further, the gastric content needs to be blocked from refluxing to the oesophagus.

In order to achieve this, the catheter 1 of the present embodiment is first inserted through the nose of the patient past the throat and into the oesophagus. It is noted that due to the fact that the passages through which the catheter 1 has to be forwarded until access to the stomach is gained have a relatively large size and relatively small tortuosity, the guidewire 100 can be omitted from the catheter 1 of the present embodiment. The catheter 1 is then forwarded towards the stomach so that the distal shaft end 28 of the catheter shaft 2 passes the gastroesophageal junction and a considerable length of the catheter shaft 2 is located inside the stomach. Then, the doctor pushes the control element 71 towards the distal shaft end 28 of the catheter shaft 2, whereby the deflated balloon 50 is moved towards the distal shaft end 28 and exits the catheter shaft 2 through the distal shaft wall opening 25, as depicted in figure 1. Then, the doctor may inflate the balloon 50 by delivering fluid thereto though the control means fluid channel 75, the conduit 10 and the flexible moving element fluid channel 310. While maintaining the balloon 50 inflated, the doctor pulls the control element 71 towards the proximal end 29 of the catheter shaft 2, thereby causing the balloon 50 to be also pulled towards the proximal end 29 of the catheter shaft 2. However, as it is still inflated, the balloon 50 cannot go back inside the lumen 21 or into the oesophagus and thus, the catheter shaft 2 can be securely arranged in the patient's body.

Figures 2 to 5 refer to a catheter 1 according to a second embodiment of the present invention. Similarly to the catheter 1 of the first embodiment, the catheter 1 of the second embodiment comprises a catheter shaft 2, a flexible moving element 3, a surgical tool 5 being an inflatable balloon 50, a distal piston 8, a proximal piston 9 and a control means 7 for controlling the balloon 50.

However, in the catheter 1 of the present embodiment, the balloon 50 is not directly connected to the flexible moving element 3 but fixed on a tool-receiving casing 6 formed as a hollow circular cylinder that extends along a longitudinal axis 600. The longitudinal axis 600 of the toolreceiving casing 6 coincides with the longitudinal axis 500 of the catheter shaft 2.

In particular, the tool-receiving casing 6 is slidably arranged on the catheter shaft 2 and can be moved in the direction of the longitudinal axis 500 of the catheter shaft 2. This is denoted by the arrows 601 and 602. Particularly, the arrow 601 denotes a movement of the tool-receiving casing 6 in the direction from the proximal shaft end 29 to the distal shaft end 28, while the arrow 602 denotes a movement of the control handle 70 in the opposite direction. The inflatable balloon 50 being fixed on the tool-receiving casing 6 is thus also movable in the direction of the longitudinal axis 500 of the catheter shaft 2.

As can be seen from figures 2 and 3, the control means 7 for controlling the movement of the balloon 50 comprises a control element 71 and a control handle 70, which are connected with each other.

The control handle 70 is formed as a hollow circular cylindrical control casing that extends in the direction of a longitudinal axis 700. The longitudinal axis 700 of the control casing coincides with the longitudinal axis 500 of the catheter shaft 2. The control casing is in particular slidably arranged on the catheter shaft 2 and can be moved in the direction of the longitudinal axis 500 of the catheter shaft 2. This is denoted by the arrows 701 and 702. Particularly, the arrow 701 denotes a movement of the control handle 70 in the direction from the proximal shaft end 29 to the distal shaft end 28, while the arrow 702 denotes a movement of the control handle 70 in the opposite direction.

It is noted that the catheter 1 of figure 3 is presented such that more details of the inner structure of the catheter 1 are made visible.

In particular, it can be seen that, similarly to the catheter 1 of the first embodiment, the flexible moving element 3 of the catheter 1 of the second embodiment is formed as a cylindrical wire 31 having a flexible moving element fluid channel 310 and that substantially extends along a longitudinal axis. The tool-receiving casing 6 is fixed to the flexible moving element 3. More specifically, the toolreceiving casing 6 is connected to a distal end 312 of the flexible moving element 3, while the proximal end 311 of the flexible moving element 3 is connected to the distal piston 8. Like in the catheter 1 of the first embodiment, the wire 31 is arranged in the lumen 21 such that the wire 31 is circumferentially supported by the catheter shaft wall 24 so that the balloon 50 is pushable by the wire 31. In particular, a diameter of the wire 31 is preferably at least 80%, more preferably at least 85%, even more preferably at least 90%, even more preferably at least 95%, most preferably substantially 100%, of a diameter of the lumen 21. Advantageously, a fit between the wire 31 and the lumen 21 is a clearance fit.

The control element 71 is connected to the control handle 70 and the proximal piston 9. Due to the proposed arrangement, a movement of the control handle 70 causes a movement of the inflatable balloon 50. The control element 71 can be formed as a stiff control element, partially flexible control element or flexible control element like the control element 71 of the catheter 1 of the previous embodiment.

For passing fluid to the control element 71 through the control handle 70 and from the toolreceiving casing 6 to the inflatable balloon 50, the control handle 70 comprises a through opening 710 and the tool-receiving casing 6 a through opening 61 , respectively.

Preferably, the flexibility of the wire 31 and/or of the control element 71 , if the latter is made as a flexible control element, may vary along their length. Particularly, a distal portion and a proximal portion of the wire 31 and/or a distal portion and a proximal portion of the control element 71 may have a smaller flexibility than their corresponding middle portions. In other words, the connecting portions of the wire 31 and/or the control element 71 with the tool-receiving casing 6 and the control casing 70 may have a higher stiffness than the rest of the wire 31. More specifically, the parts of the wire 31 that are made less flexible than the rest are the parts intended to be situated outside or to come out of the lumen 21 of the catheter shaft 2 during its movement.

As can further be seen from figure 3, the catheter shaft 2 comprises apart from the distal shaft wall opening 25 a proximal shaft wall opening 26 formed in a proximal circumferential area of the catheter shaft 2. The proximal shaft wall opening 26 communicates with the lumen 21 .

It is noted that in its first end position, the wire 31 is partially arranged in the lumen 21 and partially in the distal shaft wall opening 25, while in its second end position the wire 31 can be partially or completely arranged in the distal shaft wall opening 25. Accordingly, in its first end position, the control element 71 can be partially or completely arranged in the proximal shaft wall opening 26, while in its second end position the control element 71 is partially arranged in the proximal shaft wall opening 26 and partially in the lumen 21 .

Apart from being slidably arranged on the catheter shaft 2, the tool-receiving casing 6 is also rotatably arranged on the catheter shaft 2. In particular, the tool-receiving casing 6 and the catheter shaft 2 of the catheter 1 are threadably engaged with each other.

It can be seen from figure 4 that a right-handed thread 81 is formed in the catheter shaft wall 24 of the catheter shaft 2 in the area of the distal shaft wall opening 25. The right-handed thread 81, which is an outer thread, is in engagement with a corresponding inner thread of the toolreceiving casing 6.

In particular, the thread 81 of the catheter shaft 2 and the corresponding thread of the toolreceiving casing 6 are formed such that a movement of the control handle 70 in the direction of the longitudinal axis 500 of the catheter shaft 2 causes a rotation of the tool -receiving casing 6 around its longitudinal axis 600 in combination with a movement of the tool-receiving casing 6 in the direction of its longitudinal axis 600. In other words, the tool-receiving casing 6 is configured to perform a helical movement. This means that a force with which the control handle 70 is moved in the direction of its longitudinal axis 700 is translated into a helical movement of the tool-receiving casing 6. It is noted that the rotation of the tool-receiving casing 6 causes a torsion of the wire 31 , as the distal piston 8 cannot be rotated. Therefore, the wire 31 should be configured so as to allow torsional movement.

Due to the threaded engagement of the tool-receiving casing 6 and the catheter shaft 2 with each other, the tool-receiving casing 6 can be moved in the direction of the longitudinal axis 500 of the catheter shaft 2 in a controllable way.

In order to facilitate the rotation of the tool-receiving casing 6, the distal shaft wall opening 25 is formed as a recess extending through the catheter shaft wall 24 in the direction of the transverse axis 502. In particular, the distal shaft wall opening 25 is configured to allow a rotation of the of the tool-receiving casing 6 by up to 90 degrees in each direction with regard to a symmetry plane 503 of the catheter shaft 2.

For simplifying the manufacturing process of the catheter shaft 2, the proximal shaft wall opening 26 is also formed as a recess extending through the catheter shaft wall 24 in the direction of the transverse axis 502. However, as the control handle 70 formed as a casing does not need to be rotatably arranged on the catheter shaft 2, the proximal shaft wall opening 26 may also be formed such that a rotation of the control handle 70 is not allowed. Such a proximal shaft wall opening 26 is provided in the catheter 1 according to a fourth embodiment of the present invention that will be described later with reference to figures 6 and 7.

Figure 5 refers to a catheter 1 according to a third embodiment of the present invention.

The catheter 1 according to the third embodiment differs from the catheter 1 of the second embodiment in that the catheter shaft 2 of the catheter 1 of the third embodiment comprises a region with a right-handed thread 81 and a region with a left-handed thread 82. The right- handed thread 81 and the left-handed thread 82, which are formed as outer threads in the catheter shaft wall 24 and positioned in the area of the distal shaft wall opening 25, are in engagement with a right-handed thread and a left-handed thread of the tool-receiving casing 6, respectively. The left handed-thread and the right-handed thread of the tool-receiving casing 6 are formed as inner threads on an inner surface of the tool-receiving casing 6.

The threads 81 , 82 of the catheter shaft 2 and the corresponding threads of the tool-receiving casing 6 are formed such that a movement of the control casing 70 in the direction of its longitudinal axis 700 causes a helical movement of the tool-receiving casing 6.

The provision of threads of different directions in the tool-receiving casing 6 and the catheter shaft 2 is advantageous as turning the balloon 50 clockwise and counterclockwise makes the movement of the balloon 50 through narrow passages in the patient’s body even easier compared to a thread of the same direction. Furthermore, when the balloon 50 is inflated and anchored to a body lumen of the patient, the rotation of the tool-receiving casing 6 and thus of the balloon 50 is transformed to a corresponding rotation of the catheter shaft 2, what allows the catheter shaft 2 to be squeezed and forwarded through a narrow passage of the lumen.

Figures 6 and 7 refer to a catheter 1 according to a fourth embodiment of the present invention.

The catheter 1 according to the fourth embodiment differs from the catheter 1 of the second embodiment in the way the distal shaft wall opening 25 and the proximal shaft wall opening 26 are formed and the arrangement of the control handle 70 with respect to the catheter shaft 2.

Figure 6 shows a perspective view of a portion of the catheter 1 according to the fourth embodiment, while figure 7 shows a more detailed view of the arrangement of the flexible moving element 3 in the lumen 21 of the catheter 1. As the lumen 21 basically corresponds to a hollow area of the catheter shaft 2 and is defined by the catheter shaft wall 24, the catheter shaft wall 24 is also depicted in figure 6. However, in order to allow for a clearer view, only a part of the catheter shaft wall 24 needed to define and graphically represent the lumen 21 is shown in figure 7. In the catheter 1 according to the present embodiment, both shaft wall openings 25, 26 are formed as elongated openings, so that the tool-receiving casing 6 and the control handle 70 can only be moved in the direction of the longitudinal axis 500 of the catheter shaft 2. In other words, the tool-receiving casing 6 and the control handle 70 are not rotatably arranged on the catheter shaft 2 and thus, the balloon 50 being loaded on the tool-receiving casing 6 can also be moved only in the direction of the longitudinal axis 500.

Figures 8 and 9 refer to a catheter 1 according to a fifth embodiment of the present invention.

The basic structure, and in particular the means for moving the distal piston 8 towards the distal shaft end 29, of the catheter 1 according to the fifth embodiment corresponds in general to the basic structure, and in particular the means for moving the distal piston 8 towards the distal shaft end 29, of the catheter 1 of the first embodiment, respectively.

In other words, for moving the distal piston 8, the catheter 1 of the fifth embodiment comprises an arrangement of a control element 71, a proximal piston 9 and a space 11 between the proximal piston 9 and the distal piston 8 that is filled with an incompressible fluid like the corresponding arrangement of the catheter 1 of the first embodiment.

The means for transferring a movement of the distal piston 8 to the surgical tool 5 corresponds to the means for transferring a movement of the distal piston 8 to the balloon 50 of the catheter 1 according to the second embodiment. In other words, for causing a movement of the surgical tool 5 by movement of the distal piston 8, the catheter 1 of the fifth embodiment comprises a tool-receiving 6 and a flexible moving element 3, which are generally formed as the ones of the catheter 1 of the second embodiment.

However, a difference between the catheter 1 of the present embodiment and that of the first or second embodiment lies in that the surgical tool 5 loaded on the tool-receiving casing 6 of the catheter 1 of the fifth embodiment is a cutting device 51 instead of an inflatable balloon.

In addition, as there is no need to supply fluid to the cutting device 51 , the control means fluid channel 75 and the flexible moving element fluid channel 310 of the flexible moving element 3 are not provided in the catheter 1 of the present embodiment. Thus, the control element 71 and the flexible moving element 3 are formed as solid (not hollow) elements. Within this framework, also the conduit 10 and the through opening 61 of the tool-receiving casing 6 are not provided in the catheter 1 of the present embodiment.

For example, the cutting device 51 can be an atherectomy blade. The catheter 1 can then be used as an endovascular catheter for cutting away an atheroma (atheromatous plaque), i.e. an abnormal accumulation in the inner layer of the wall of a blood of an artery. In order to achieve this, the catheter 1 will be positioned in the vicinity of the atheroma inside the affected artery. Then, the doctor may move the control element 71 towards the atheroma, thereby causing the atheroctomy blade to move towards the atheroma and eventually cut it. in order to more effectively move the cutting device 51 towards the proximal shaft end 29 of the catheter shaft 2, i.e. to pull back the cutting device 51 , a connecting means 12 can be provided between the distal piston 8 and the proximal piston 9. The connecting means 12 supports the effect of the negative pressure that builds up in the space 11, when the proximal piston 9 is moved towards the proximal shaft end 29 of the catheter shaft 2 by pulling the control element 71.

The catheter 1 according to the present embodiment can also be used as a urological catheter in a prostatectomy procedure. In this case, the cutting device 51 is a prostate cutter.

Figures 10 and 11 refer to a catheter 1 according to a sixth embodiment of the present invention.

The catheter 1 according to the sixth embodiment differs from the catheter 1 according to the second embodiment in that the tool-receiving casing 6 also serves as a control handle for controlling the movement of the surgical tool 5, in this case the inflatable balloon 50.

In other words, the tool-receiving casing 6 and the control handle 70, more specifically the control casing in the catheter 1 of the second embodiment correspond in functional terms to the tool-receiving casing 6 of the catheter 1 of the sixth embodiment. By using an alternative formulation, the tool-receiving casing 6 of the catheter 1 of the sixth embodiment can be described as the tool-receiving casing 6 and the control handle 70 of the catheter 1 of the second embodiment being integrated with each other or, in other words, made in a single piece.

To serve the purpose of controlling the movement of the balloon 50, the tool-receiving casing 6 extends from a proximal portion to a distal portion of the catheter shaft 2. In particular, the toolreceiving casing 6 has a length that allows it to be arranged partially inside and partially outside the patient's body. In particular, a length of the tool-receiving casing may be more than 70%, preferably more than 80%, and less than 100% of a length of the catheter shaft 2. Further, the tool-receiving casing 6 is connected to the proximal piston 9 by the control element 71.

Thus, as can be seen in particular from figure 11 , the tool-receiving casing 6 is distally connected with the flexible moving element 3 and proximally connected with the control element 71. A force applied by the doctor to the tool-receiving casing 6 at its proximal region 63 is transferred to the distal region 62 of the tool-receiving casing 6 via the control element 71, the proximal piston 9, the incompressible fluid, the distal piston 8 and the flexible moving element s. Figure 12 shows a perspective view of a portion of a catheter 1 according to a seventh embodiment of the present invention.

The catheter 1 according to the seventh embodiment generally corresponds to the catheter 1 of the sixth embodiment.

However, in contrast to the catheter 1 of the sixth embodiment, the catheter 1 according to the seventh embodiment has a catheter shaft 2 and a tool -receiving casing 6 of different shapes.

More specifically, the tool-receiving casing 6 is formed as a hollow circular cylinder, while the catheter shaft 2 preferably comprises at least one region with a varying cross-section in the direction of its longitudinal axis 500. Thus, an inner surface of the tool-receiving casing 6 and an outer surface of the catheter shaft 2 are not complementary to each other.

In particular, the catheter shaft 2 comprises a plurality of frustoconical regions in the present embodiment. The frustoconical regions are specifically extend and are arranged in the direction of the longitudinal axis 500 of the catheter shaft 2 such that the catheter shaft 2 and the toolreceiving casing 6 contact each other only partially when they are moved relative to each other.

It is noted that it is also possible that the catheter shaft 2 comprises regions of another shape and/or with a different arrangement relative to each other, as long as the catheter shaft 2 and the tool-receiving casing 6 do not fully contact each other.

What is achieved by the described configuration of the catheter 1 is that a sliding friction between the catheter shaft 2 and the tool-receiving casing 6 can be reduced.

Figure 13 shows a cross-section of a tool-receiving casing 6 of a catheter 1 according to an eighth embodiment of the present invention.

The catheter 1 according to the eighth embodiment differs from the catheter 1 according to the sixth embodiment in that the balloon 50 is provided with fluid through a casing lumen 64 formed in the wall of the tool-receiving casing 6, and not through the control means fluid channel 75, the conduit 10, the flexible moving element channel 310 and the opening 61 of the tool -receiving casing 6. However, it is possible that both described pathways for delivering fluid to the balloon 50 are provided in the catheter 1 .

As the casing lumen 64 has to be accessed from outside of the patient’s body, the casing lumen 64 advantageously extends from the proximal portion 63, in particular a proximal end, to a distal portion 62 of the tool-receiving casing 6. In this case, the opening 61 of the tool-receiving casing 6 is formed such that it establishes a fluid connection between the casing lumen 64 and the inflatable balloon 50. Figure 14 shows a cross-sectional view of a tool-receiving casing 6 of a catheter 1 according to a ninth embodiment of the present invention.

The catheter 1 of the ninth embodiment generally corresponds to the catheter 1 according to the second embodiment.

5 The only difference is that the tool-receiving casing 6 of the catheter 1 of the ninth embodiment comprises an open cross-section. Preferably, the tool-receiving casing 6 is formed with an open cross-section over its whole length.

Due to this design, the flexibility of the tool-receiving casing 6 is increased compared to a toolreceiving casing 6 with a closed cross-section like the one the catheter 1 of the second0 embodiment. This enables the catheter 1 to be more easily forwarded through narrow passages and tortuous lumens of the patient's body.

In the following, a general principle of the operation of a catheter 1 with an inflatable balloon 50 according to the present invention will be described with reference to figures 15 and 16. Figure 15 shows the catheter 1 in a first and a second state inside a body lumen 800, while figure 165 shows the catheter 1 in a third and a fourth state inside the body lumen 800.

In the first state, which is represented by dotted lines in figure 15, the catheter 1 is positioned at the site of interest inside the body lumen 800, while the inflatable balloon 50 is deflated. Then, the doctor inflates the balloon 50 and operates the catheter 1 such that the catheter shaft 2 is forwarded inside the body lumen 800. In order to achieve this, the doctor will push the catheter shaft 2 forward. The state in which the catheter shaft 2 has been moved forward and the balloon 50 is inflated corresponds to the second state of the catheter 1. The second state of the catheter 1 is represented by solid lines in figure 15.

Then, the doctor deflates the balloon 50, while the catheter shaft 2 remains in its position. This state corresponds to the third state and is represented by dotted lines in figure 16.

Following the deflating step of the balloon 50, the doctor will operate the catheter 1 such that the balloon 50 is moved forward and relative to the catheter shaft 2. This corresponds to the fourth state of the catheter and is shown in figure 16 with solid lines.

The process can be repeated until the catheter shaft 2 has been forwarded by the desired distance, e.g. a distance corresponding to the length of a blockage in the body lumen 800.

A more detailed operation of a catheter 1 according to the present application will be presented in the following. Firstly, an endovascular application of a catheter 1 of the present invention will be described in detail. In this case, the catheter 1 may also be characterized as an endovascular catheter. The surgical tool 5 is preferably an inflatable balloon 50.

More specifically, a catheter 1 of the present invention can be used as a support catheter for providing support to the guidewire 100 when it is being pushed through a narrowing of a blood vessel, e.g. an artery. Such a blockage may be caused by a build-up of a substance called plaque on the inner walls of the artery. Blood flowing over the top of the plaque tends to clot and thus can cause a further increase of the narrowing of the artery, which may eventually result in a blockage of the artery and consequently in a total occlusion.

In order to open an artery narrowed by plaque, a single guidewire can potentially be used. In particular, the guidewire can be fed to the site of the blockage and pushed through the narrowing of the artery. However, if the blockage is large and the plaque is hardened, the use of a single guidewire turns out to be insufficient, as the guidewire bends at its tip due its flexibility and thus cannot be forwarded through the blockage.

This problem can be overcome by using a catheter 1 according to the present invention.

At first, the catheter 1 is forwarded to the site in front of the blockage and the guidewire 100 is pushed forward so that it exits through the tip opening of the catheter shaft 2. Due to the support of the guidewire 100 by the catheter shaft 2, the guidewire 100 is able to go through to a first part of the blockage. If the surgeon handling the catheter 1 continues to push the guidewire 100, the guidewire 100 might be pushed a bit further through the blockage, but will eventually reach a point, at which a further pushing movement by the surgeon will cause the guidewire 100 to start bending, what will in turn will cause the catheter shaft 2 to start being pushed against the arterial wall.

As soon as the surgeon realizes that the catheter shaft 2 tends to be pushed against the arterial wall, the surgeon stops pushing the guidewire 100 any further and inflates the balloon 50 until it is anchored to the arterial wall. This provides a further support to the guidewire 100, so that the guidewire 100 can now be pushed further through the blockage. Again, when the guidewire 100 is pushed to the extent that a certain length is outside of the catheter shaft 2, the support of the catheter shaft 2 will not anymore be enough to prevent the guidewire 100 from bending, if the guidewire 100 is pushed further. As this bending would occur inside the blockage, this could cause some damage to or ever perforate the artery.

At this stage, while the balloon 50 is inflated, the surgeon immobilizes the component of the catheter 1 provided for controlling the movement of the balloon 50 and pushes the catheter shaft 2 forward. By doing so, the force with which the surgeon pushes the catheter shaft 2 is transferred to the balloon 50, which is actually that what pushes the catheter shaft 2 through the blockage. As the catheter shaft 2 has been moved forward, the guidewire 100 is almost completely covered again by the catheter shaft 2. The reason for the catheter shaft 2 being able to be moved forward through the blockage is that the balloon 50 is very close to the site of the

5 blockage and thus the force with which the catheter shaft 2 is pushed towards the blockage is high enough so that the catheter shaft 2 can overcome the resistance through the blockage.

Then, the surgeon pushes the guidewire 100 forward once more. The guidewire, being again supported by the catheter shaft 2, manages to go further through the blockage, until the guidewire 100 starts to bend again, when the length of the guidewire 100 being not anymore0 covered by the catheter shaft 2 has again reached a certain length.

The surgeon then repeats the procedure until the catheter shaft 2 manages to go through the blockage.

If the blockage is of a considerable length, the maximum distance by which the catheter shaft 2 and the balloon 50 can be moved relative to each other might be not large enough for the catheter shaft 2 to cover all the length of the blockage by just alternately moving the guidewire 100 and the catheter shaft 2 as described above.

In this case, after the catheter shaft 2 has been moved relative to the balloon 50 by the maximum possible distance after the execution of the aforementioned steps, the surgeon will deflate the balloon 50, while stabilizing the catheter shaft 2, and move it forward by moving forward the component of the catheter 1 that controls the balloon 50. After having brought the deflated balloon 50 to the new desired position, the surgeon inflates the balloon 50 so that it gets anchored to the arterial wall at the new desired position.

Then, the steps of alternating movements of the guidewire 100 and the catheter shaft 2 as presented above can be repeated, thereby allowing the supported guidewire 100 to be pushed further and eventually to exit the blockage.

The surgeon may now deflate the balloon 50 and pull the catheter 1 of the present invention out of the patient, while holding the guidewire 100 in place. At this point, only the guidewire 100 is located inside the patient’s body. In particular, the tip of the guidewire 100 is located in a healthy part of the artery past the blockage. The guidewire 100 can then serve as the guide for bringing a catheter having a stent to the site where the blockage was located.

To summarize, the procedure for distending a blockage in an artery using a catheter 1 according to the present invention comprises alternate forward movements of the guidewire 100 and the catheter shaft 2, while the balloon is in its inflated state, so that the guidewire 100 is always supported by the catheter shaft 2 when being moved forward. In case the blockage has a considerable length, the procedure additionally comprises the step of deflating the balloon 50 when the catheter shaft 2 has been moved by the maximum possible distance relative to the balloon 50, the step of subsequently moving the balloon 50 forward to a new position closer to or even inside the blockage and the step of anchoring the balloon 50 at the new position in

5 order to provide again support to the guidewire 100 and the catheter shaft 2.

It is noted that in the beginning of the procedure the balloon 50 will generally be located outside, more specifically in front of, the blockage, while it will be progressively be placed closer to the blockage site or even inside the widened part of the blockage.

By having the balloon 50 inflated and anchored within the artery, a force applied to the balloon 50, which would otherwise cause the balloon 50 to move relative to the catheter shaft 2, is translated into a movement of the catheter shaft 2 relative to the balloon 50 and the artery. Thus, the catheter shaft 2 can move within the artery accurately and powerfully both forwards and backwards, because of the inflated - anchored balloon 50. In particular, the balloon 50 may have a movement range of a few centimetres close to the tip 201 of the catheter shaft 2. This practically means that the propulsive force that moves the catheter shaft 2 is applied close to its tip 201, achieving maximal pushability of the tip 201 and therefore of the catheter shaft 2 as a whole, since the propulsion force is applied at a distance closer to the tip 201 . .

In the following, a nasogastric application of a catheter 1 of the present invention will be described. In this case, the catheter 1 may also be characterized as a nasogastric catheter and can be used for gaining access to the stomach and its contents, enabling drainage of the gastric contents or preventing a reflux of the gastric contents to the oesophagus, decompressing the stomach, obtaining a specimen of the gastric contents or introducing a passage into the gastrointestinal tract.

The surgical tool 5 is preferably an inflatable balloon 50.

According to a first technique, the doctor inserts the catheter 1 through the nose of the patient, past the throat and down into the stomach and places it at a position, at which gastric contents can be drained. At this stage, the balloon 50 is in its deflated state.

When it is ensured that the catheter shaft 2 is placed at the desired position, the doctor inflates the balloon 50. The doctor then moves the inflated balloon 50 towards the proximal end of the catheter shaft 2 by manipulating the component of the catheter 1 that controls the balloon 50, while keeping the catheter shaft 2 stable.

When the balloon 50 reaches the area of the gastrooesophageal junction and contacts the upper wall of the stomach, it cannot move any further, as due to its inflated state the balloon has a larger cross-sectional area than the oesophagus. At this moment, the doctor feels In his/her hand that the catheter shaft 2 tends to move towards the stomach. The doctor immediately stops moving the balloon 50 any further and stabilizes it at this position. Following these steps, it can be ensured that the catheter shaft 2, more specifically its distal shaft end 28, is securely placed at the desired position inside the gastric contents, as the inflated balloon 50 prevents the catheter from being accidentally pulled out of the nose of the patient. More importantly, the inflated balloon 50 isolates the stomach from the oesophagus. Thereby, the gastric contents cannot enter the oesophagus and there is no risk of an aspiration pneumonia.

If it is preferred that the balloon 50 is anchored to the oesophagus, the doctor, after completing the aforementioned steps, deflates the balloon 50 and pulls it towards the oesophagus, while maintaining the position of the catheter shaft 2. When the balloon 50 is located inside the oesophagus, the doctor may inflate the balloon 50 again, so that it is anchored to the oesophagus.

According to a second technique, the doctor feeds the catheter 1 through the nose, past the throat into the oesophagus of the patient, until, depending on the patient’s height, the catheter shaft 2 has entered the stomach but not reached a position yet, at which the gastric contests can be drained. In other words, the distal shaft end 28 of the catheter shaft 2 is positioned such that it is not located inside the gastric contents. At this stage, the balloon 50 is deflated and located in the oesophagus of the patient.

Then, the doctor inflates the balloon 50, thereby anchoring it to the oesophagus. While maintaining the balloon 50 inflated and the component of the catheter 1 that controls the movement of the balloon 50 stabilized so that the balloon 50 cannot be moved, the doctor pushes the catheter shaft 2 further inside the stomach of the patient. In addition to pushing the catheter shaft 2, the doctor may rotate the catheter shaft 2 in order to achieve the desired position in the patient's stomach, i.e. to achieve that the distal shaft end 28 of the catheter shaft 2 is positioned within the gastric contents. When the desired position has been reached, the doctor stabilizes the balloon 50, thereby also stabilizing the catheter 1 at the desired position.

In case the inflated balloon 50 has to remain inside the patient's oesophagus for a longer period of time, what may cause complications to the patient, or if any complications have already arisen due to the presence of the inflated balloon 50 in the patient's oesophagus, the doctor may decide to reposition the balloon 50 inside the oesophagus. To this end, the doctor will deflate the balloon 50 and move it to a new position, while maintaining the present position of the catheter shaft 2. After that, the doctor will inflate the balloon 50 again, thereby stabilizing it at its new position to the oesophagus. By doing so, already existing complications can be dealt with or future complications can be avoided, as the balloon 50 will not press the oesophagus at the same position for the whole time that the catheter 1 is placed inside the patient. The particular advantage of the catheter 1 of the present invention is that the repositioning of the balloon 50 can be done without having to first remove the catheter 1 out of the patient and/or having to use a new catheter of a different length.

According to a third technique, the surgeon introduces the catheter 1 through the nose, past the throat, the oesophagus and the stomach and into the duodenum of the small intestine. At this stage, the balloon 50 is in a deflated state and located inside the stomach. The balloon 50 is then inflated and moved proximally, while the catheter shaft 2 is stabilized. Similarly to the second technique, when the balloon 50 reaches the area of the gastrooesophageal junction and contacts the upper wall of the stomach, it cannot move any further, as it has a larger cross- sectional area than the oesophagus due to its inflated state. At this moment, the doctor feels in his/her hand that the catheter shaft 2 tends to move towards the stomach. The surgeon immediately stops moving the balloon 50 any further and stabilizes it at this position. In case the surgeon wants to move the balloon to a new position within the oesophagus, the balloon 50 has first to be deflated and then moved proximally past the gastrooesophageal junction. When the new desired position inside the oesophagus has been reached, the balloon 50 is inflated again. Alternatively, the balloon 50 can be placed from the beginning inside the oesophagus. This is in particular advantageous, if the catheter shaft 2 has to be forwarded in a subsequent step into the small intestine further than the duodenum.

A further nasogastric application of the catheter 1 of the present application is described below.

More specifically, a catheter 1 of the present invention can be used in the case of an oesophageal stricture, i.e. a narrowing or tightening of the oesophagus that causes swallowing difficulties. The stricture usually occurs at the distal end of the oesophagus.

Firstly, the doctor introduces the catheter 1 through the nose and past the throat into the oesophagus of patient until the tip 201 of the catheter shaft 2 reaches the site of the stricture. During this step, the balloon 50 of the catheter 1 is in its deflated state and located inside the oesophagus. At this point, the doctor inflates the balloon 50, which is thus anchored to the oesophagus, thereby providing support to the tip 201 of the catheter shaft 2. If, instead, the doctor continued to push the catheter shaft 2 forward with the balloon 50 being deflated, the catheter shaft 2 not being able to pass through the stricture would start to bend and coil up inside the oesophagus.

Following the inflating step of the balloon 50, the doctor pushes the catheter shaft 2 forward while stabilizing the component of the catheter 1 that controls the movement of the balloon 50. Thereby, the doctor transfers the force with which the catheter shaft 2 is pushed to the inflated balloon 50, which is actually that what pushes the catheter shaft 2 through the stricture. The fact that the catheter shaft 2 manages to go through the stricture relies on that the balloon 50 is anchored to the oesophagus close to the stricture and thus the force with which the balloon 50 pushes the catheter shaft 2 is sufficiently high to overcome the resistance of the stricture.

The catheter shaft 2 is pushed in this state until it has entered the stomach, more specifically by the time a considerable length of the catheter shaft 2 is situated inside the stomach. While maintaining the catheter shaft 2 stable, the doctor now deflates the balloon 50 and pushes it forward by manipulating the component of the catheter 1 that controls its movement.

When the balloon 50 is located inside the stomach, the doctor inflates it again. Then, the doctor pulls the inflated balloon 50 towards the proximal end of the catheter shaft 2, until the doctor feels a resistance due to the balloon 50 touching the upper walls of the stomach. While keeping the component of the catheter 1 that controls the movement of the balloon 50 stable, the doctor now pushes the catheter shaft 2 forward. Again, the balloon 50 is the component of the catheter 1 that forces the catheter shaft 2 to be forwarded further inside the stomach. When the desired position is reached, the doctor stops pushing the catheter shaft 2 and stabilizes the balloon 50 on the catheter shaft 2.

Finally, a urological use of the catheter 1 of the present invention will now be described. In this case, the catheter 1 may also be characterized as a urological catheter.

More specifically, the catheter 1 of the present invention can be used in the case of a urethral stricture. A urethral stricture involves scarring that narrows the lumen that carries urine out the urethra and thus restricts the flow of urine from the bladder, thereby increasing the risk for the occurrence of a variety of medical problems in the urinary tract, including inflammation or infection. In particular, a urethral stricture can occur due to enlargement of the prostate (prostate hyperplasia).

In order to gain access to the urinary bladder, the doctor may insert the catheter 1 of the present invention into the urethra of the patient up to the stricture in the area of the prostate.

The procedure to be followed in order for the catheter 1 to enter the urinary bladder is similar to that followed in the case of an oesophagus stricture. At the end of the procedure, the distal end 28 of the catheter shaft 2 is located inside the urinary bladder, while the catheter shaft 2 cannot accidentally be removed out of the patient's body due to the balloon 50 being inflated inside the urinary bladder and in contact with the lower walls thereof.

Figure 17 shows a part of a catheter T according to an example.

As can be seen from figure 17, the catheter 1 ' comprises a catheter shaft 2' with a tip 201 ’ and a main part 200' attached to each other. The catheter shaft 2’ extends along a longitudinal axis 500’ between a proximal shaft end 29’ and a distal shaft and 28'. A first lumen 2T, a second lumen 23' and a third lumen 22' are formed in the catheter shaft 2'. The third lumen 22’ is configured to receive a guidewire and/or to pass fluid therethrough. The first lumen 2T and the second lumen 23’, which extend parallel to the longitudinal axis 500’, are connected with each other by a curved lumen connection 213’. In particular, the first lumen 2T and the second lumen 23’ are connected to each other at their corresponding distal ends. Their proximal ends are not connected to each other. This means that the first lumen 2T, the second lumen 23’ and their curved lumen connection 213' form together an open looped lumen.

The catheter T further comprises a tool-receiving casing 6’, which is longitudinally movably, in particular slidably, arranged on the catheter shaft 2' and on which a surgical tool 5’, in particular an inflatable balloon 50’, is fixed. The tool-receiving casing 6' extends along a longitudinal axis 600’, which coincides with the longitudinal axis 500’.

For moving the surgical tool 5’, an arrangement of a first flexible element 41’ and a second flexible element 42’ being connected to each other is provided. The first flexible element 4T is movably arranged in the first lumen 21' but not in the second lumen 23’ and the curved lumen connection 213'. The second flexible element 42’ is arranged in the second lumen 23’ and the curved lumen connection 213’ such that it is movable in the second lumen 23’, the curved lumen connection 213' and the first lumen 21'. Thus, the first and second flexible elements 41’, 42’ form an open flexible element loop. As can further be seen from figure 17, both the first and second flexible elements 41’, 42' have a much smaller outer dimension, in particular diameter, compared to the inner dimension, in particular diameter, of the second lumen 23’, the curved lumen connection 213' and the first lumen 21’.

The first flexible element 41' is connected to the tool-receiving casing 6’, so that a movement of the first flexible element 41 ' causes the tool-receiving casing 6' to move. In particular, in order to move the surgical tool 5' towards the distal shaft end 28’ of the catheter shaft 2, the second flexible element 42' has to be pulled. Accordingly, in order to move the surgical tool 5’ towards the proximal shaft end 29’ of the catheter shaft 2, the first flexible element 4T has to be pulled. In other words, it becomes apparent that a movement of the surgical tool 5’ in each of the directions towards the distal shaft end 28' and the proximal shaft end 29’ is effected by a pulling force applied to the corresponding flexible element 41 ’ or 42'. It becomes thus apparent that the catheter T according to the example of figure 17 differs from the catheter 1 of the present invention, as in the catheter 1 of the present invention a movement of the surgical tool 5 towards the distal shaft end 28 can be effected by a pushing force instead of a pulling force.

For delivering fluid to the balloon 50’, the first flexible element 4T is hollow. For example, the first flexible element 4T can be formed as a (hollow) wire. The first flexible element 4T can communicate with the balloon 50’ through a distal shaft wall opening 25' formed in catheter shaft wall 24'. The second flexible element 42’ can for example be formed as a solid wire.

If the surgical tool 5’ is not an inflatable balloon 50', the first flexible element 41’ and the second flexible element 42’ can be formed as a single flexible element that is movably arranged in the first lumen 21’, the curved lumen connection 213’ and the second lumen 23'. The single flexible element can then be formed as a solid (not hollow) flexible element such as a wire or a thread.

The depicted and described features and further properties of the invention's embodiments can arbitrarily be isolated and recombined without leaving the gist of the present invention.

In addition to the foregoing description of the present invention, for an additional disclosure explicit reference is taken to graphic representation of figures 1 to 16.

List of reference signs

1 , 1’ catheter

2, 2' catheter shaft

3 flexible moving element

5, 5’ surgical tool

6, 6’ tool-receiving casing

7 control means

8 distal piston

9 proximal piston

10 conduit

11 space

12 connecting means

20 catheter shaft

21 lumen

21’ first lumen

22 further lumen

22’ second lumen

23' third lumen

24, 24’ catheter shaft wall

25, 25' distal shaft wall opening

26 proximal shaft wall opening

27 further shaft wall opening

28, 28’ distal shaft end

29, 29’ proximal shaft end

31 wire

41' first flexible element

42’ second flexible element

50, 50’ balloon

51 cutting device

61 opening

62 distal region

63 proximal region

64 casing lumen

70 control handle 71 control element

81 thread

82 thread

75 control means fluid channel

100 guidewire

200, 200' main part

201 , 201’ tip

213' curved lumen connection

310 flexible moving element fluid channel

311 proximal end

312 distal end

410 channel (second channel)

500, 500' longitudinal axis 501 circumferential direction

502 transverse axis

503 symmetry plane

600, 600’ longitudinal axis

601 arrow

602 arrow

700 longitudinal axis

701 arrow

702 arrow

710 opening

711 control element fluid channel

800 body lumen

Claims

1. A catheter (1 ), comprising:

• a catheter shaft (2) that extends along a longitudinal axis (500) and comprises a lumen (21 ) defined by a catheter shaft wall (24),

• a flexible moving element (3),

. a surgical tool (5) connected to the flexible moving element (3),

• a distal piston (8) and a proximal piston (9), wherein: the distal piston (8) and the proximal piston (9) are arranged in the lumen (21) and a space between the distal piston (8) and the proximal piston (9) is filled with an incompressible fluid, the distal piston (8) is connected to the flexible moving element (3), and the flexible moving element (3) is arranged in the catheter shaft (2) in such a way that the flexible moving element (3) is at least partially circumferentially supported by the catheter shaft wall (24) so that a movement of the proximal piston (9) in a direction from a proximal shaft end (29) of the catheter shaft (2) to a distal shaft end (28) of the catheter shaft (2) causes a movement of the surgical tool (5).

2. The catheter (1) of claim 1, wherein the catheter shaft (2) comprises a distal shaft wall opening (25) that is formed in a distal circumferential area of the catheter shaft (2) and communicates with the lumen (21) and/or a proximal shaft wall opening (26) that is formed in a proximal circumferential area of the catheter shaft (2) and communicates with the lumen (21), and/or wherein the lumen (21) extends from the proximal shaft end (29) of the catheter shaft (2) or wherein a proximal end of the lumen (21) is spaced apart from the proximal shaft end (29) of the catheter shaft (2).

3. The catheter (1) of any of the preceding claims, wherein at least the flexible moving element portion that is movably arranged in the lumen (21) between a first end position and a second end position of the flexible moving element (3) has a cross-sectional area over at least a part of its whole length that is at least 80%, more preferably at least 85%, even more preferably at least 90%, even more preferably at least 95%, most preferably substantially 100%, of a cross-sectional area of the lumen (21 ), and/or wherein at least the flexible moving element portion that is movably arranged in the lumen (21 ) between a first end position and a second end position of the flexible moving element (3) has over at least a part of its whole length the same shape with the lumen (21), in particular wherein at least said flexible moving element portion and the lumen (21) are formed as circular cylinders, in particular wherein at least said flexible moving element portion has over at least a part of its whole length a diameter that is at least 80%, more preferably at least 85%, even more preferably at least 90%, even more preferably at least 95%, most preferably substantially 100%, of a diameter of the lumen (21), and/or wherein the flexible moving element (3) is arranged in the lumen (21) in such a way that the flexible moving element portion that is movably arranged in the lumen (21) between a first end position and a second end position of the flexible moving element (3) has over at least a part of its whole length a shape that is complementary to a shape of the lumen (21).

4. The catheter (1 ) of any of the preceding claims, wherein the surgical tool (5) is directly connected to the flexible moving element (3) and/or wherein the surgical tool (5) is longitudinally movably arranged on the catheter shaft (2), in particular wherein the surgical tool (5) is directly arranged on the catheter shaft (2).

5. The catheter (1) of any of claims 1 to 3, further comprising a tool-receiving casing (6) that is longitudinally movably arranged on the catheter shaft (2), wherein the tool-receiving casing (6) is connected to the flexible moving element (3) and wherein the surgical tool (5) is arranged on the tool-receiving casing (6).

6. The catheter (1) of claim 5, wherein the tool-receiving casing (6) is rotatably arranged on the catheter shaft (2), in particular wherein the tool-receiving casing (6) and the catheter shaft (2) are threadably engaged with each other.

7. The catheter (1) of any of claim 5 or 6, wherein at least a portion of the tool-receiving casing (6) comprises an open cross-section.

8. The catheter (1) of any of claims 5 to 7, wherein the tool-receiving casing (6) is connected to the proximal piston (9) and extends from a proximal portion to a distal portion of the catheter shaft (2) such that the tool-receiving casing (6) serves as a control handle for controlling the movement of the surgical tool (5), in particular wherein the tool-receiving casing (6) is connected to the proximal piston (9) by a control element (71), wherein the control element (71) is formed as a stiff control element, in particular a shaft, connected to or formed integrally with the proximal piston (9), or wherein the control element (71) is formed as a flexible control element and arranged in such a way that the control element (71 ) is at least partially circumferentially supported by the catheter shaft wall (24) so that the proximal piston (9) is movable towards the distal shaft end (28) of the catheter shaft (2) by the control element (71 ).

9. The catheter (1) of claim 8, wherein the surgical tool (5) is an inflatable balloon (50) and the tool-receiving casing (6) comprises a casing lumen (64) that communicates with the inflatable balloon (50) for inflating the balloon (50).

10. The catheter (1 ) of any of claims 1 to 7, further comprising a control means (7) for controlling the movement of the surgical tool (5), wherein the control means (7) comprises a control element (71 ), wherein the control element (71) is formed as a stiff control element, in particular a shaft, connected to or formed integrally with the proximal piston (9), or wherein the control element (71) is formed as a flexible control element, which is connected to the proximal piston (9) and arranged in such a way that the control element (71) is at least partially circumferentially supported by the catheter shaft wall (24) so that the proximal piston (9) is movable towards the distal shaft end (28) of the catheter shaft (2) by the control element (71).

11. The catheter (1) of claim 10, wherein the control means (7) further comprises a control handle (70) connected to the control element (71), in particular wherein the control handle (70) is formed as a casing that is longitudinally movably, in particular slidably, arranged on the catheter shaft (2).

12. The catheter (1) of any of the preceding claims, wherein the distal piston (8) and the proximal piston (9) have the same or different piston areas.

13. The catheter (1) of any of the preceding claims, wherein the surgical tool (5) is an inflatable balloon (50), wherein the flexible moving element (3), the distal piston (8) and the proximal piston (9) are hollow and wherein the flexible moving element is in fluid communication with the balloon (50) and a conduit (10) that is arranged between the distal piston (8) and the proximal piston (9).

14. The catheter (1) of claim 8 to 12, wherein the flexible moving element (3) and the flexible control element (71) are made as a single element being connected to the distal piston (8) and the proximal piston (9) which are hollow to allow the single element to pass through, in particular wherein the surgical tool (5) is an inflatable balloon (50) and the single element is hollow and in fluid communication with the balloon (50).

15. The catheter (1) of any of the preceding claims, wherein the catheter shaft (2) comprises at least one further lumen (22) for receiving a guidewire (100) and/or passing fluid therethrough.