EP4236845A2

EP4236845A2 - Medical expansion system for expanding a long bone, and kit

Info

Publication number: EP4236845A2
Application number: EP21806996.1A
Authority: EP
Inventors: Ulrich Schreiber
Original assignee: OT Medizintechnik GmbH
Current assignee: OT Medizintechnik GmbH
Priority date: 2020-10-31
Filing date: 2021-10-29
Publication date: 2023-09-06
Also published as: WO2022090510A3; WO2022090510A2; US20230404639A1

Abstract

The invention relates to a medical expansion system (100) for expanding a bone (200), more particularly for expanding a long bone, comprising: - an expansion unit (1), which extends in a longitudinal direction (L) and has a first end (EE1) and a second end (EE2), the expansion direction of the expansion unit (1) optionally being oriented substantially radially (R); - a connecting catheter (3), a first end (EV1) of which is connected to a first end (EE1) of the expansion unit (1); and - a port (5), which is connected to a second end (EV2) of the connecting catheter (3); wherein the expansion unit (1), the connecting catheter (3) and the port (5) are fluidically connected to each other, and the expansion system (100) is sealed off from the surroundings fluid-tight.

Description

description

Medical expansion system for expanding a long bone and kit

The invention relates to a medical expansion system according to claim 1 , to a kit according to claim 32 and to a method according to claim 35 .

Bones are damaged in different ways in everyday life, for example on the one hand due to bone fractures caused by external influences (injuries) or by infections or on the other hand by tumors (osteosarcoma, Ewing's sarcoma). In some cases, the damaged bone can no longer heal. One option is then a bone transplant, i.e. the removal of a bone segment from another bone segment of the same organism that is not absolutely necessary for mobility. An example is the removal of a fibula segment (fibula). The functionality of the lower leg, which is limited after removal, can largely be maintained by the tibia (shinbone). However, a fibula segment can only be transplanted directly to a limited extent, for example if a femur segment is to be replaced. After the transplantation, the corresponding bone must be stabilized for a certain period of time using marrow nails or the like. However, due to its small diameter, the fibula segment is not suitable for such intramedullary nails.

It is the object of the present invention to provide a proposal for solving this problem. The object of the invention can be achieved by the medical expansion system with the features of

Claim 1, by the kit having the features of claim 32 and by the method having the features of claim 35.

The medical expansion system, also known as expansion system for short, is used to expand a bone, in particular to expand a long bone. It includes :

- an expansion unit (e.g. at least one expansion balloon or dilatation balloon) extending in a longitudinal direction and having a first and a second end. The expansion unit is preferably designed to expand substantially radially, or more radially than longitudinally, e.g. B. at least 5 times or at least 10 times more in the radial direction than in the longitudinal direction, the expansion direction of the expansion unit.

- a connecting catheter, which is connected with a first end thereof to a first end of the expansion unit; and

a port preferably connected to or part of a second end of the connecting catheter.

The expansion unit, the connecting catheter and the port, resp. their inner lumen, are in fluid communication with each other. The expansion system is fluid-tight to the outside and / accordingly self-contained, ie z. B. compared to the environment.

The expansion system is preferably closed in such a way that no Exchange of fluid with the surrounding tissue or the fluid present in the expansion system does not escape from the expansion system into the surrounding tissue, and surrounding tissue fluids do not enter the expansion system.

The kit according to the invention comprises at least one expansion system according to the invention and at least one liquid, preferably a physiological saline solution (NaCl, eg.), The expansion system or the closed expansion unit being filled with this liquid during use.

The method according to the invention serves to expand a bone, in particular to expand a tubular bone. It includes providing an expansion system according to the invention or a kit according to the invention. It further comprises advancing the first end or portion of the expansion unit via an access into an opened interior of the bone in order to implant the expansion unit in whole or in part between fragments or bone sections of the bone.

If it is disclosed herein that the object according to the invention has one or more features in a specific embodiment, it is also disclosed here in each case that the object according to the invention expressly does not have this or these features in other embodiments that are also according to the invention has e.g. B. as a disclaimer. It is therefore true for each embodiment mentioned herein that the opposite embodiment, for example formulated as a negation, is also disclosed. In all of the foregoing and in all of the following statements, the use of the expression "may be" or "may have" etc. synonymous with "is preferably" or "has preferably" etc. to understand and is intended to explain embodiments of the invention.

Whenever numerical words are mentioned herein, the person skilled in the art understands them as indicating a numerical lower limit. Provided that this does not lead to a discernible contradiction for the person skilled in the art, the person skilled in the art always reads "at least one" or "at least one" when specifying "a" or "an". This understanding is also included in the present invention, as is the interpretation that a numerical word such as "a" can alternatively be meant as "exactly one", wherever this is technically possible for a person skilled in the art. Both are covered by the present invention and apply to all numerals used herein.

Advantageous further developments of the present invention are each the subject of dependent claims and embodiments.

If an embodiment is mentioned here, this is to be understood as an exemplary embodiment according to the invention, which is not to be understood as limiting.

Embodiments according to the invention can have one or more of the features mentioned above and/or below in any combination, provided such a combination is not recognized as technically impossible for a person skilled in the art. In some embodiments, the first end of the connecting catheter and the first end of the expansion unit are detachably connected to one another by means of a first connector.

In some embodiments, a second end of the connecting catheter and the port are detachably connected to one another by means of a second connector.

In some embodiments, the port has a membrane for puncturing the port to deliver or withdraw a fluid. This serves to change the pressure prevailing in the expansion system and the radial expansion of the expansion unit.

In some embodiments, the membrane has a membrane structure for piercing by means of a cannula (eg injection needle).

The tightness of the expansion system in relation to the environment is retained. The membrane structure is preferably designed in such a way that a tight seal is ensured during and after the puncture with a static pressure of up to 20 bar.

In some embodiments, the expansion unit is or includes a dilation balloon.

In some embodiments, the expansion unit is a rotationally symmetrical body.

In some embodiments, the expansion unit is an elongated body, the length of which exceeds the diameter of the expansion unit by at least a factor of 2, 3, 5, or 10. In some embodiments, the radial diameter of the expansion unit in the maximum expanded state is a maximum of 30 mm.

In some embodiments, the radial diameter is a maximum of 4 mm in a non-expanded state.

In some embodiments, the length of the expansion unit in its longitudinal orientation is between 3 cm and 30 cm, e.g. B. in an unexpanded state.

In some embodiments, the expansion system is disposable or a one-time system, in others it is not.

In some embodiments, the expansion system includes or consists of sterilizable and/or biocompatible materials and/or is sterilized.

In some embodiments, the components of the expansion system are pressure-stable up to at least 20 bar. In this way, a kink-resistant arrangement, in particular of the connecting catheter, can be brought about. In addition, the required tightness of the system can be ensured.

In some embodiments, the expansion unit is formed within a surrounding, possibly multi-layer hose or tube, preferably an elastic one

Plastic tubing is provided and expanded therein. Materials for this are z. B. silicone, a thermoplastic elastomer, etc .

In some embodiments, the expansion unit lies within a surrounding, possibly multi-layer mesh, Tissue or braid before is expanded herein and / or is thereof, at least partially, surrounded.

In some embodiments, the expansion unit has several, preferably different, diameters, cross-sections and/or lumens along its longitudinal axis, optionally with several turning points and/or different gradients.

In some embodiments, multiple expansion units, e.g. B. Dilation balloons combined in parallel or in series for expansion.

In some embodiments, e.g. B. of the method according to the invention, the expansion unit is expanded/deflated under pressure and/or volume control, with the expansion taking place in at least 5 steps and the deflation being able to take place in one or more steps.

In some embodiments, the components of the expansion system are provided and designed for their connection in situ and/or, especially for the first time, filling with liquid in situ or emptying there.

In some embodiments, the liquid has pharmacological active ingredients that increase the shelf life, sterility, sterility or other properties of the liquid over the duration of the implantation, ie z. B. can or should ensure at least 30 days, 50 days, 80 days or more.

In some versions, the components of the

Expansion system preassembled or together at the factory connected before . The expansion system can thus easily

Assembly or connection steps are implanted.

In some embodiments, the expansion system has an elastic or non-elastic sheath, preferably manufactured or present separately, for at least partially surrounding the, e.g. B. non-compliant or semi-compliant or compliant expansion unit on . The shell can completely or partially surround the expansion unit and limit, mitigate or the like the expansion and thus protect the expansion unit from damage.

In some embodiments, the shell is configured to allow smooth, radial expansion and/or contraction of the expansion unit. This can be effected or promoted in particular by means of material properties and/or predetermined geometry.

In some embodiments, the connecting catheter is designed to be pressure and kink-resistant in such a way that no, or no significant, ie z. B. no more than 5% increase in circumference, expansion of the connecting catheter is recorded, with a minimum bending radius of 5 mm, there is no kink in the connecting catheter that interrupts the fluid communication between port and expansion unit, and/or the connecting catheter preferably has a length of 2 cm to 50 cm having . Such configurations can advantageously allow the port to be placed at an anatomically preferred location.

In some embodiments, the radial diameter of the expansion unit in an unexpanded state is between 1 mm and 10 mm. In some embodiments, the expansion system is designed and provided to cause bone callus tissue and surrounding soft tissue to expand upon expansion of the expansion unit.

In some embodiments, some or all of the exterior surfaces of the port and/or connector catheter and/or expansion device that may contact bone or surrounding tissue during use have a drug coating such as e.g. B. bone growth factor, antibiotics, antibacterial substances, etc., have.

In some embodiments, pharmacologically active ingredients, such as antibiotics, growth factors, etc., which preferably have a depot or long-term effect, and which z. B. over the application period of 15 to 80 days.

In some embodiments, the expansion system of any preceding claim is designed to remain fully implanted in the body for a period of 10 to 80 days. In some embodiments, e.g. B. the method according to the invention, it remains so long.

In some forms of execution, the expansion system has no connector for an injection device for injecting liquid (or it is not used), but the z. B. placed subcutaneously, port is punctured by means of a cannula. In some embodiments, the port is intended and configured to also be implanted (and in some embodiments will be), e.g. B. subcutaneous .

In some embodiments, the expansion unit and/or the connecting catheter comprises a flexible or rigid support structure running axially to the expansion unit, e.g. B. a tube, core, sleeve, wire, rod, mesh, or any combination thereof.

In some embodiments, the support structure is stiffer or stronger than the innermost layer of the expansion unit.

In some embodiments, the support structure runs, at least in sections, through an interior of the expansion unit.

In some embodiments, the support structure extends through a central portion of a cross section and longitudinally of the expansion unit.

In some embodiments, the port is or includes a pump. It is designed to pump or inject volume from a volume reservoir into the expansion unit at the instigation of a user or automatically (e.g. by means of a control device that communicates with the pump in a wired or wireless manner.

In some embodiments, the expansion unit is designed to be implanted in bone after an osteotomy between a free bone fragment and the bone of origin. In some embodiments, one to ten or more fixation eyelets and/or X-ray markers are attached to the expansion unit and/or the connection catheter, which allow the expansion unit and/or the connection catheter to be fixed with sutures in order to avoid dislocation during the period of use and / or to enable position control by X-ray imaging.

In some embodiments, the kit also has an injection syringe, preferably with an injection needle, for preferably gradually filling or further filling the expansion system or the expansion unit with a liquid, preferably a physiological saline solution.

In some embodiments, the expansion system or the kit also has a first x-ray marker, preferably at the first end or area of the expansion unit, and/or a second x-ray marker, preferably at the second end or area of the expansion unit.

In some embodiments, the method further includes at least one of the following steps:

- Opening up access to the interior, in particular to the medullary cavity, of the bone, preferably via the caput, e.g. B. the caput fibulae ;

- dilating the access using a dilator, preferably via a guide wire;

opening a bone window at the shaft of the bone by osteotomy; and or Connecting the interior with a protective sleeve.

In some embodiments, the method further includes a gradual expansion of the expansion unit by volume injection via the port after a latency period of about 3 to 12 days, in which bone callus tissue has formed between the osteotomized bone of origin and the loosened bone fragment, which thus leads to callus distraction of the bone callus tissue leads . This can be done by the pump's controller or a syringe pump, or manually by the user.

In some embodiments, one, several or all parts or sections of the X-ray marker consist of a cobalt-chromium alloy (CoCr) or have such an alloy.

In some embodiments, one, several or all parts or sections of the x-ray marker are made of titanium, in particular grade 5 titanium, or contain titanium.

In some embodiments, one, several or all parts or sections of the x-ray marker consist entirely or partially of pyrocarbon and/or ceramic.

In some embodiments, one, several or all parts or sections of the x-ray marker consist partially or entirely of a plastic (in particular polyethylene, in particular highly crosslinked polyethylene, in particular with vitamin E) or includes such a material.

In some embodiments, the expansion system can be fully implanted, or is already fully implanted. In some embodiments, the expansion system has no pressure or liquid source, the expansion unit is not in fluid communication with the expansion unit.

In some embodiments, the expansion system and/or the kit does not have any control device by means of which an actuator, such as a pump, would be controlled, in particular according to a predetermined algorithm or, above all, automatic or programmed sequence, in order to act on the expansion unit , e.g. B. by means of liquid.

In some embodiments some or all of the advantages mentioned above or below are achievable.

The expansion system according to the invention can be implanted completely temporarily due to its optionally outwardly fluid-tight structure. As a result, the risk of infection can advantageously be reduced or completely avoided. This has a very high clinical relevance since infections in the bone area can have serious consequences.

The vitality of the expanded bone obtained according to the invention can also be an advantage, the fact that 100% autologous material can be made available for repairing the bone defect, that a closed procedure for expanding the “donation” bone is possible, and the standardized procedure for this.

The high biomechanical quality, the rapid healing associated with early mobilization and the low surgical risk can also be advantageous. The invention, in particular the medical expansion system, is described below with reference to preferred embodiments. However, the invention is not limited to these embodiments. In the figures:

Fig. 1 shows the inventive medical

Expansion system of an embodiment in a perspective view;

Fig. 2 shows the kit according to the invention

From embodiment in perspective view;

Fig. 3a-c show the expansion unit in different

embodiments;

4a-e show further embodiments of the expansion unit;

5a, b show the connecting catheter in different embodiments;

6a-c show a schematic sequence for using the medical expansion system according to the invention on a long bone;

7a-g show in a schematically simplified manner the individual steps or phases of the expansion of the long bone by means of the expansion system according to the invention;

Figures 8a-d show further details of the individual steps of Figure 7; Fig. 9a, b show the removal of a bone segment and the preparation of the bone for bone transplantation using the expansion system according to the invention;

Fig. 10a-d show the steps of FIG. 9 subsequent steps for preparing the bone to be transplanted using the expansion system according to the invention;

Fig. 11a, b show the steps of FIG. 10 subsequent steps of an osteotomy to prepare the bone to be transplanted with the aid of the expansion system according to the invention;

Fig. 12a-d show further possible steps for preparing the bone to be transplanted and the use of the expansion system according to the invention; and

Fig. 13a-c show the final bone graft of the graft expanded with the aid of the expansion system according to the invention.

Fig. 1 shows an exemplary embodiment of the medical expansion system 100 according to the invention, partly from the side and partly in a perspective view.

The medical expansion system 100 , referred to here and below simply as the expansion system 100 , has an expansion unit 1 extending in a longitudinal direction L with a first end EE1 and a second end EE2 . The direction of expansion Expansion unit 1 is essentially aligned in the radial direction R.

The expansion system 100 also has a connecting catheter 3 , which is connected with a first end EVI thereof to the first end EE1 of the expansion unit 1 . The connection can be made by means of an optional, first connector 7; alternatively, it can be made with a material connection.

The expansion system 100 also has a port 5 which is connected to a second end EV2 of the connecting catheter 3 . The connection can be made by means of an optional, second connector 9, alternatively it can be made with a material connection.

The port 5 is provided here with a membrane 11 as an example. It fluidly closes off the fluid system of the expansion system 100 from the outside. In the embodiment shown here, the membrane 11 can be provided, e.g. B. by means of a cannula 301, see FIG. 2 to be punctured .

Fluid can be supplied to the closed fluid system via the cannula 301 by means of a syringe 300, as also shown in FIG. 2 is shown.

Fig. 2 shows an embodiment of the kit 400 according to the invention in a perspective view.

In this embodiment, the kit 400 optionally includes an expansion system 100 according to the invention, which is filled with a liquid, preferably a physiological saline solution, and a syringe 300 with a cannula 301 for, preferably gradual, further filling of the expansion system 100 with liquid from the Syringe 300 . The expansion unit 1, the connecting catheter 3 and the port 5 are in fluid communication with each other. The expansion system 100 is fluid-tight to the outside towards the environment U. In other words, the expansion system 100 is self-contained.

Fig. 3a-c show the expansion unit 1 in different embodiments.

Fig. 3a shows the expansion unit 1 in an optional, tubular embodiment in which the outside diameter is constant over the length L. An optional inner, concentric support structure 3d can advantageously increase the stability of the expansion unit 1 before and/or during an implantation. The concentric support structure 3d can be a wire, a cable, a rod, a fabric or the like, purely by way of example.

Fig. 3b shows the expansion unit 1 in an optional embodiment that widens in the shape of a trumpet toward an end area. This can be used to advantage, for example, to particularly widen or widen certain longitudinal sections of a long bone. to expand .

Fig. 3c shows the expansion unit 1 in an optional embodiment that widens in a trumpet shape towards both end areas.

Fig. 3d shows the expansion unit 1 in a further, optional embodiment. The expansion or Expansion takes place optionally in individual sections la or Segments la along the entire length of the expansion unit 1 . The segments 1a can be formed uniformly or differently, for example of different lengths, with different diameters, with different materials and/or of different structures. This can advantageously be used for different bone structures and/or implantation areas with regard to the surrounding soft tissue structures and/or the course of the outer contour of the bone.

Fig. 4a-e show further embodiments of the expansion unit 1.

Fig. 4a shows an optional expansion unit 1 in a multi-lumen embodiment. The lumens 1b arranged in parallel can be arranged uniformly or differently within an outer shell (shell, mantle). The widening of the bone can thus advantageously take place selectively in order to influence different bone regions and/or surrounding tissue structures differently. In the illustration to the right of FIG. 4a shows how the expansion pressure of the individual lumina can affect the expansion unit 1 in a schematically simplified manner.

Fig. 4b shows a further, optional expansion unit 1 in a multi-lumen embodiment, the individual lumens 1c being arranged concentrically and/or in multiple layers. In the illustration to the right of FIG. 4b shows the widening of an osteotomized bone in a schematically simplified manner. A callus formation can form between the bone segments, in particular gradually.

Fig. 4c shows an optional expansion unit 1 in a further embodiment, in which case the widening does not take place uniformly radially over the circumference. The selective Radial expansion over the circumference is achieved by means of different structures of the expansion unit 1, as is exemplified in FIG. 4c is shown. The corresponding selective widening of the bone is schematically simplified in the illustration to the right of FIG. 4c shown.

Fig. 4d shows the expansion unit 1 in a further optional embodiment, which essentially corresponds to the illustration in FIG. 3a corresponds to . The optional core that supports the expansion unit 1 and does not expand itself can be rigid or flexible.

Fig. 4e shows the expansion unit 1 in a further optional embodiment, with the support structure 3d optionally also being arranged in areas outside of the core. The support structure 3d can have a fabric or a mesh or consist of such. The support structure 3d can be arranged concentrically around a core.

Fig. 5a, b show the connecting catheter 3 in different embodiments.

Fig. 5a shows the connecting catheter 3 with an optional end area A, which enables a liquid to be introduced directly into the expansion system 100. FIG. Similar to an introduction by means of a separate port 5 , the end area A can have a membrane 11 for puncturing an injection needle 301 , for example. In this way, the connecting catheter 3 does not require a connection to a port, or its end region A with the membrane 11 is the port. Fig. 5a shows the connecting catheter 3 with a further, optional end area A, which can have a cylindrical, oval, rectangular or other shape, for example.

Fig. 6a-c show a schematic sequence for using the medical expansion system 100 according to the invention on a long bone 200 or an embodiment of the method according to the invention.

Fig. 6a shows a schematically simplified expansion of a bone segment that has been osteotomized on the longitudinal side. The direction of expansion is indicated by the radial arrow shown perpendicular to the longitudinal direction. By means of a gradual expansion, callus can form between the bone segments that gradually move away from each other. This is shown by the single, arcuate lines.

Fig. FIG. 6b shows a simplified schematic view of an optional arrangement of the expansion system 100 in the area of the lower extremities of a human being. The expansion unit 1 is arranged in the fibula (calf bone) right next to the tibia (shin bone).

The connecting catheter 3 connects the expansion unit 1 to a port 5 in the area of the femur

(Thighbone) is arranged.

Fig. 6c shows in a simplified, schematic manner in the four individual representations from top to bottom, with the respective cross sections on the right, the gradual expansion of the osteotomized long bone 200 by means of the expansion system 100 according to the invention over time (from top to bottom). Fig. 7a-g show schematically simplified the individual steps for the expansion of the osteotomized long bone 200 with the expansion system 100 according to the invention.

Fig. 8a-d show further details of the individual steps of FIG. 7a-g .

Fig. 9 a , b show the removal of a bone segment that is to be replaced by a bone transplant that has been transplanted and prepared by means of the expansion system 100 according to the invention. Until the bone transplant has been sufficiently widened by means of the expansion system 100 , the area of the removed bone segment is temporarily supplied with a so-called spacer 13 .

Fig. 1Oa-d show those of FIG. 9 subsequent steps for preparing the bone segment to be transplanted using the expansion system 100 according to the invention.

Fig. 11a, b show those of FIGS. 10 subsequent steps of an osteotomy to prepare the bone to be transplanted using the expansion system 100 according to the invention.

Fig. 12a-d show the further steps to be carried out for the preparation of the bone 200 to be transplanted and the insertion of the expansion system 100 according to the invention.

Fig. 13a-c shows the final bone graft of the graft 10 expanded using the expansion system 100 of the present invention.

The pages of figures following FIGS. 1 to 13c again show the objects according to the invention in exemplary embodiments. those shown in it According to the invention, articles can be combined with any other features disclosed herein in any combination.

Reference List

100 medical expansion system

200 bones

300 syringe

301 cannula

400 kit

EE1 first end of expansion unit

EE2 second end of expansion unit

EVI first end of connecting catheter

EV2 second end of connecting catheter

L Longitudinal

Rradial

U environment

I expansion unit la section , segment of the expansion unit

1b parallel lumen of the expansion unit

1c concentric lumen of expansion unit

3 connecting catheters

3d support structure

5 ports

7 first connector

9 second connector

II membrane

13 spacers

Claims

Expectations

Having a medical expansion system (100) for expanding a bone (200), in particular for expanding a long bone

- an expansion unit (1) extending in a longitudinal direction (L) with a first (EE1) and a second (EE2) end, wherein the expansion direction of the expansion unit (1) is optionally aligned substantially radially (R);

- A connecting catheter (3) having a first end (EVI) thereof connected to a first end (EE1) of the expansion unit (1); and

- A port (5) which is connected to a second end (EV2) of the connecting catheter (3); wherein the expansion unit (1), the

Connecting catheter (3) and the port (5) are in fluid communication with each other and the expansion system (100) is fluid-tight to the outside.

2. Expansion system (100) according to claim 1, wherein the first end (EVI) of the connecting catheter (3) and the first end (EE1) of the expansion unit (1) are detachably connected to one another by means of a first connector (7).

3. Expansion system (100) according to claim 1 or 2, wherein a second end (EV2) of the connecting catheter (3) and the port (5) are detachably connected to one another by means of a second connector (9).

4. Expansion system (100) according to any one of the preceding claims, wherein the port (5) has a membrane (11) for puncturing the port (5) for supplying or removing a fluid.

5. Expansion system (100) according to the preceding claim, wherein the membrane (11) has a membrane structure for piercing by means of a cannula (301).

6. expansion system (100) according to any one of the preceding claims, wherein the expansion unit (1) is or comprises a dilation balloon.

7. expansion system (100) according to any one of the preceding claims, wherein the radial diameter of the expansion unit (1) is a maximum of 30 mm in the maximum expanded state.

8. Expansion system (100) according to any one of the preceding claims, wherein the length of the expansion unit (1) in its longitudinal orientation is between 3 cm and 30 cm.

9. Expansion system (100) according to any one of the preceding claims, wherein the expansion system (100) is a disposable system.

10. Expansion system (100) according to any one of the preceding claims, wherein the expansion system (100) comprises or consists of sterilizable and/or biocompatible materials and/or is sterilized.

11. Expansion system (100) according to any one of the preceding

Claims, wherein the components of the Expansion system (100) are pressure-stable up to at least 20 bar.

12. Expansion system (100) according to any one of the preceding claims, wherein the expansion unit (1) expands within a surrounding optionally multi-layer hose or a tube, preferably an elastic plastic hose.

13. Expansion system (100) according to any one of the preceding claims, wherein the expansion unit (1) expands within a surrounding, optionally multi-layer mesh, fabric or braid and/or is at least partially surrounded by it.

14. Expansion system (100) according to any one of the preceding claims, wherein the expansion unit (1) has several, preferably different, diameters, cross sections and/or lumens with optionally several turning points and/or different gradients along its longitudinal axis.

15. Expansion system (100) according to any one of the preceding claims, wherein the expansion unit (1) in the longitudinal or circumferential direction multiple expansion units (1) or dilatation balloons combined in parallel or in series for expansion.

16. Expansion system (100) according to any one of the preceding claims, wherein the expansion unit (1) pressure and / or volume controlled expanded / deflated, wherein the expansion takes place in at least 5 steps and the deflation can take place in one or more steps.

17. Expansion system (100) according to one of the preceding claims, wherein the components of the expansion system (100) are provided and configured for their connection in situ and/or, above all for the initial filling with liquid in situ or emptying there.

18. Expansion system (100) according to any one of the preceding claims, wherein the components of the expansion system (100) are preassembled and the expansion system (100) is fully assembled for its implantation.

19. Expansion system (100) according to any one of the preceding claims, comprising a, preferably separately manufactured or existing, elastic shell for, at least partially, surrounding, z. B. non-compliant or semi-compliant or compliant manufactured expansion unit (1).

20. Expansion system (100) according to claim 19, wherein the shell is designed to enable a uniform, radial expansion and/or contraction, in particular by means of material properties and/or predetermined geometry.

21. Expansion system (100) according to one of the preceding claims, wherein the connecting catheter (3) is designed to be pressure and kink-resistant, so that the connecting catheter (3) does not expand at pressures of up to 20 bar, and with a minimum bending radius of 5 mm no kink occurs in the connecting catheter (3) which interrupts the fluid communication between port (5) and expansion unit (1), and wherein the connecting catheter (3) preferably has a length of 2 cm to 50 cm.

27

22. Expansion system (100) according to any one of the preceding claims, wherein the radial diameter of the expansion unit (1) in a non-expanded state is between 1 mm and 10 mm.

23. Expansion system (100) according to any one of the preceding claims, designed to cause an expansion of bone callus tissue and surrounding soft tissue during the expansion of the expansion unit (1).

24. Expansion system (100) according to any one of the preceding claims, wherein some or all of the outer surfaces of the port (5) and / or connecting catheter (3) and / or expansion unit (1) in contact with the bone (200) or surrounding tissue can stand, a medicinal coating.

25. Expansion system (100) according to one of the preceding claims, wherein pharmacologically active substances are integrated into the shell, outer surfaces or the like which are intended to be in contact with tissue during use.

26. The expansion system (100) according to any one of the preceding claims, designed to remain fully implanted in the body for a period of 10 to 80 days.

27. Expansion system (100) according to one of the preceding claims, wherein for the injection of liquid there is no connection via a connector of an in ection device, but the subcutaneously placed port is punctured with a cannula.

28 Expansion system (100) according to any one of the preceding claims, wherein the expansion unit (1) and / or the connecting catheter (3) an axial, f lexible / rigid support structure (3d), z. B. a tube, a core, a sleeve, a wire, a rod, a mesh. Expansion system (100) according to one of the preceding claims, wherein the port (5) is or has a pump designed to deliver or inject volume into the expansion unit (1) from a volume reservoir at the instigation of a user or automatically. Expansion system (100) according to any one of the preceding claims, wherein the expansion unit (1) is designed to be implanted in the bone (200) after osteotomy between a freely mobile bone fragment and the bone of origin. Expansion system (100) according to one of the preceding claims, wherein one to ten or more fixation eyelets and/or X-ray markers are attached to the expansion unit (1) and/or the connecting catheter (3), which fix the expansion unit (1) and/or the Allow connection catheter (3) over sutures to avoid dislocation during the application period and / or to enable position control by X-ray imaging. Kit with at least one expansion system (100) according to any one of the preceding claims; and

29 - At least one liquid, preferably a physiological saline solution, wherein the expansion system (100) or the closed expansion unit (1) is filled with this liquid. The kit of claim 32 further comprising

- An injection syringe, preferably with an In ection needle for, preferably gradual, filling or further filling of the expansion system (100) or the expansion unit (1) with a liquid, preferably a physiological saline solution. The kit of claim 32 or 33 further comprising

- A first x-ray marker, preferably at the first end (EE1) or area of the expansion unit (1), and/or a second x-ray marker, preferably at the second end (EE2) or area of the expansion unit (1). Method for expanding a bone (200), in particular for expanding a long bone, with the steps:

- Providing an expansion system (100) according to any one of the preceding claims 1 to 31 or a kit according to any one of claims 32 to 34;

- Advancing the first end (EE1) or area of the expansion unit (1) via an access into an opened interior of the bone (200).

30 The method of claim 35, further comprising at least one of the steps:

- Opening access to the interior, in particular to the medullary cavity, of the bone (200), preferably via the caput, e.g. B. the caput fibulae;

- dilating the access using a dilator, preferably over a guide wire;

- opening a bone window at the shaft of the bone (200) by osteotomy; and or

- Connecting the inside with a protective sleeve. The method according to any one of claims 35 to 36, wherein a gradual expansion of the expansion unit (1) by volume injection via port (5) takes place after a latency phase of about 3 to 12 days, in which bone callus tissue has formed between the osteotomized original bone and the loosened bone fragment, what thus leading to callus distraction of bone callus tissue.

31