WO2025166005A1 - Apparatus and method for determining positional information of intra-body steerable assembly - Google Patents

Abstract

An apparatus and method for determining positional information of a steerable assembly within an animal body utilizing a plurality of fiber bragg grating (FBG) sensors arranged along a length of an elongated fiber. A polymeric tube having a sealed end contains the elongated fiber and FBG sensors to form a sheathed FBG sensor assembly. A reference point of the elongated fiber is fixable to an external support structure, and a portion of the assembly is insertable through a passage defined by the steerable assembly within the body. A method includes fixing the reference point of the elongated fiber, inserting the sheathed sensor assembly into a passage of the steerable assembly, and recording a configuration of the elongated fiber utilizing the FBG sensors.

Description

APPARATUS AND METHOD FOR DETERMINING POSITIONAL INFORMATION OF INTRA-BODY STEERABLE ASSEMBLY

CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims priority to U.S. Provisional Patent Application No. 63/549,049 filed on February 2, 2024, wherein the entire contents of the foregoing application are hereby incorporated by reference herein.

TECHNICAL FIELD

[0002] This disclosure relates generally to assemblies that are steerable (e.g., surgical instruments and borescopes) within a body, and relates more specifically to systems and methods for determining positional information of steerable assemblies.

BACKGROUND

[0003] Various types of minimally invasive surgery involve passing steerable assemblies such as catheters, needles, and endoscopes through an incision or orifice into an animal (e.g., human) body, to perform various ablation, embolization, device placement, and other procedures. Categories of minimally invasive surgeries include endoscopy, laparoscopy, arthroscopy, interventional radiology, etc. Minimally invasive surgery typically has less operative trauma, other complications, and adverse effects than a corresponding open-type surgery (involving a larger incision to permit direct viewing and manipulation of tissue by a surgeon).

[0004] Minimally invasive surgeries frequently use image guidance to help surgeons in the localization of the surgical tool. The main imaging techniques include magnetic resonance imaging (MRI), computed tomography (CT), ultrasound, and fluoroscopy. Such tracking devices impose limitations on surgical systems. For example, MRI scanners have a confined space that creates limitations for surgical robots. Additionally, MRI scanners generate strong magnetic fields that render it difficult to utilize ferromagnetic and paramagnetic materials in conjunction with MRI imaging. CT scanning has other disadvantages, such as patient exposure to high doses of radiation (X-rays), disruption of brain imaging by nearby bones, and presence of localized artifacts within images. While attractive for near-surface procedures, ultrasonic imaging provides limited resolution as depth increases, ultrasonic waves are susceptible to being blocked by b ones, and artifacts may be common in ultrasound images.

[0005] One method to determine position of a steerable assembly within tissue of an animal body without requiring imaging is disclosed in International Publication No. WO 2021/108690 A1 , which names the same co-inventors as the present application. Such publication discloses use of a steerable assembly comprising an elongated structure (e.g., an elongated body structure), an implement arranged at a distal end thereof, and fiber bragg grating (FBG) sensors (having an associated optical fiber) arranged in or on the elongated structure. FBG sensors include fixed sensing points along an optical fiber that can capture the shape of the fiber in three dimensions. An FBG physically stretches and contracts on the nanometer scale in response to physical changes in the environment that cause the center or Bragg wavelength to change. Light signals may be supplied via the optical fiber to the FBG sensors by a FBG driver/detector arranged external to the animal body, wherein reflected light signals received by the FBG driver/detector may be used to determine one or more of force, strain, or shape of the FBG sensors associated with the elongated structure, and thereby used to determine orientation of the elongated structure. The disclosed method further comprises determining a length of insertion of the elongated structure into the tissue of the animal body. The disclosed method further comprises using the FBG sensors, sensing one or more conditions indicative of at least one of force, shape, or strain experienced by the FBG sensors during insertion of the elongated structure, determining a three- dimensional trajectory of the steerable assembly from (i) the insertion length, and (ii) the sensed one or more conditions, and superimposing the three-dimensional trajectory (into the animal body) of the steerable assembly on a (previously-constructed) three- dimensional model of the tissue of the animal body. The resulting positional determination does not require real-time imaging of the tissue during insertion of the elongated structure, but can provide real-time positional information of the elongated structure in which the FBG sensors are received.

[0006] There exist limitations of the tracking method disclosed by WO 2021/108690 A1 that may restrict its utility. One limitation is that FBG sensors and an associated fiber according to such method remain present within a passage of an elongated structure during a surgical procedure, thereby consuming valuable space in the elongated structure that might otherwise be used to provide other functionality, such as to permit delivery or use of various items. Another limitation is that FBG sensors and an associated fiber are generally not capable of determining exact position of other items within the body (but outside the elongated structure), such as magnetically responsive surgical clips and the like. Such surgical clips may also be referred to as magnetic tissue anchors or tissue clips, which permit tissue within a body to be grasped and manipulated by a moveable magnet that is positioned external to the body. A further limitation is that an elongated structure may itself be magnetically responsive, and it may be difficult to prevent an elongated structure from being unintentionally moved when a magnet external to a body is utilized to manipulate magnetically responsive surgical clips.

[0007] There also exist applications outside the surgical context for tracking a steerable assembly within a non-animal body - for example, inspection of equipment and structures using borescopes and the like.

[0008] In view of the foregoing, the art continues to seek improvement in systems and methods for determining positional information of a steerable assembly within a body (including but not limited to an animal body) to enhance their utility.

SUMMARY

[0009] Aspects of the present disclosure relate to an apparatus and method for determining positional information of a steerable assembly within a body, utilizing a plurality of fiber bragg grating (FBG) sensors arranged along a length of an elongated fiber. An apparatus includes a polymeric tube containing the elongated fiber and the plurality of FBG sensors to form a sheathed fiber bragg grating sensor assembly, with the tube having a sealed distal tube end. A reference point of the elongated fiber is configured to be fixed to an external support structure, and a portion of the sheathed FBG sensor assembly is insertable through a passage defined by the steerable assembly within the body. A surgical system may utilize the foregoing apparatus and steerable assembly. A FBG driver/detector may be used to receive reflected light signals and used to determine one or more of force, strain, or shape of the plurality of FBG sensors. A method includes fixing a reference point of an elongated fiber to an external support structure (i.e. , arranged external to a body into which a steerable assembly will be inserted), inserting a distal portion of the elongated fiber with multiple FBG sensors into a passage of the steerable assembly, and recording a configuration of the elongated fiber utilizing the FBG sensors when at least a portion of the elongated fiber is received by the passage and the steerable assembly is arranged within a body. [0010] In one aspect, the disclosure relates to an apparatus for determining positional information of a steerable assembly within a body. The apparatus includes a plurality of FBG sensors arranged along a length of an elongated fiber, and includes a polymeric tube containing the elongated fiber and the plurality of FBG sensors to form a sheathed FBG sensor assembly. The polymeric tube includes a sealed distal tube end, wherein a distal end of the elongated fiber is arranged proximate to the sealed distal tube end, and at least a portion of the elongated fiber is affixed to the polymeric tube. At least a portion of the sheathed FBG sensor assembly is configured to be inserted through a passage defined by the steerable assembly when the steerable assembly is within the body. A reference point of the elongated fiber (optionally positioned at or near a proximal end thereof) is configured to be fixed to an external support structure at a specified distance relative to a base of a robotic arm that is configured to manipulate one or more magnetically responsive elements within the body.

[0011] In certain embodiments, the sheathed FBG sensor assembly comprises a distal portion and a medial portion, and the distal portion comprises a greater number of FBG sensors per unit length of the elongated fiber than the medial portion.

[0012] In certain embodiments, the polymeric tube is configured to be disposable, with the at least a portion of the elongated fiber being removably affixed to the polymeric tube to permit the elongated fiber to be removed from the polymeric tube and inserted into another polymeric tube for re-use.

[0013] In certain embodiments, the external support structure comprises the base of the robotic arm, and the reference point of the elongated fiber is configured to be fixed directly to the base of the robotic arm.

[0014] In certain embodiments, the external support structure comprises a table to which the base of the robotic arm is mounted.

[0015] In certain embodiments, a surgical system comprises the above-described apparatus and the steerable assembly, wherein the steerable assembly comprises an elongated body structure including a proximal end configured to be inserted into the body, the proximal end comprising an aperture arranged at an end of the passage defined by the steerable assembly; and a proximal end of the sheathed FBG sensor assembly is configured to extend through the aperture.

[0016] In certain embodiments, the elongated body structure comprises a plurality of passages configured to permit delivery or use of one or more of a camera, a grasping tool, a cutting tool, a surgical clip, and a therapeutic agent.

[0017] In certain embodiments, the surgical system further includes the robotic arm, wherein the robotic arm comprises or more magnets arranged external to the body. [0018] In certain embodiments, the surgical system further includes a FBG driver/detector arranged external to the body, wherein the FBG driver/detector is configured to receive reflected light signals useable to determine one or more of force, strain, or shape of the plurality of FBG sensors.

[0019] In certain embodiments, the body comprises an animal or human body. [0020] In another aspect, the disclosure relates to a method for determining positional information of a steerable assembly within a body. The method includes multiple steps. One step includes fixing a reference point of an elongated fiber to an external support structure, the elongated fiber comprising a plurality of FBG sensors arranged along a length of the elongated fiber. Another step includes inserting a distal portion of the elongated fiber including at least some FBG sensors of the plurality of FBG sensors into a passage defined by the steerable assembly. Another step includes recording a configuration of the elongated fiber utilizing the at least some FBG sensors when some or all of the distal portion of the elongated fiber is received by the passage, and when the steerable assembly is arranged within the body.

[0021] In certain embodiments, the distal portion of the elongated fiber including the at least some FBG sensors is arranged within a polymeric tube to form a sheathed FBG sensor assembly.

[0022] In certain embodiments, the polymeric tube is configured to be disposable, with the at least a portion of the elongated fiber being removably affixed to the polymeric tube to permit the elongated fiber to be removed from the polymeric tube and inserted into another polymeric tube for re-use.

[0023] In certain embodiments, the method further includes causing a distal end of the sheathed FBG sensor assembly to extend through an aperture at an end of the passage defined by the steerable assembly and contact a magnetically responsive item within the body, wherein the recording of the configuration of the elongated fiber is performed when the distal end of the sheathed FBG sensor assembly is in contact with the magnetically responsive item.

[0024] In certain embodiments, the magnetically responsive item comprises a magnetically responsive surgical clip.

[0025] In certain embodiments, the sheathed FBG sensor assembly comprises a distal portion and a medial portion, and the distal portion comprises a greater number of FBG sensors per unit length of the elongated fiber than the medial portion.

[0026] In certain embodiments, the fixing of the reference point of the elongated fiber is performed at a specified distance relative to a base of a robotic arm that is configured to manipulate one or more magnetically responsive elements within the body.

[0027] In certain embodiments, the specified distance is in a range of 0 to 20 cm. [0028] In certain embodiments, the external support structure comprises a base of a robotic arm that is configured to manipulate one or more magnetically responsive elements within the body, and the reference point of the elongated fiber is fixed directly to the base of the robotic arm.

[0029] In certain embodiments, the steerable assembly comprises an elongated body structure that defines a plurality of passages configured to permit delivery or use of one or more of a camera, a grasping tool, a cutting tool, a surgical clip, and a therapeutic agent.

[0030] In certain embodiments, the method further includes using a FBG driver/detector arranged external to the body to receive reflected light signals and to determine one or more of force, strain, or shape of the plurality of fiber bragg grating. [0031] In certain embodiments, the body comprises an animal or human body.

[0032] In another aspect, any two or more features of aspects and/or embodiments disclosed herein may be combined for additional advantage.

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 schematically illustrates an optical fiber having multiple FBG sensors along its length, wherein each FBG sensor serves as an individual sensing point.

[0035] FIG. 2 illustrates a surgical clip including a premagnetized weight arranged within a gastric cavity of an animal body, with a grasping or affixing element thereof attached to a portion of gastric wall tissue.

[0036] FIG. 3 schematically illustrates interconnections between components of a system for determining positional information of a steerable assembly having an elongated structure (e.g., surgical instrument) and a plurality of FBG sensors, within an interior of a body according to one embodiment, the system further including robotic magnetic manipulators arranged external to the body.

[0037] FIG.4 is a top plan view of a fiber having a plurality of FBG sensors coupled with a FBGS control box, with a reference point of the fiber at a fixed point relative to a surgery operation table, and showing the fiber having a non-linear shape.

[0038] FIG. 5A is a side view of a fiber having a plurality of FBG sensors according to one embodiment.

[0039] FIG. 5B is a side view of a (reduced length) fiber having a plurality of FBG sensors arranged proximate to a polymeric tube configured to receive the fiber and FBG sensors to produce a sheathed FBG sensor assembly.

[0040] FIG. 5C is a side view of a sheathed FBG sensor assembly including the fiber and FBG sensors arranged within the polymeric tube as shown in FIG. 5B.

[0041] FIG. 6 schematically illustrates a fiber with a plurality of FBG sensors, showing a sensorized part and a non-sensorized part, and depicting spacing differences between FBG sensors in different regions thereof.

[0042] FIG. 7 is a perspective view of a robotic arm incorporating magnets to serve as an end effector to effectuate movement of a steerable assembly with a body (e.g., to manipulate a magnetic needle within tissue of an animal body) according to certain embodiments.

[0043] FIG. 8 schematically illustrates a portion of an FBG sensor that may be utilized with a system for determining position of a steerable assembly (e.g., a surgical instrument or borescope) within a body according to certain embodiments.

[0044] FIG. 9 is a schematic diagram of a generalized representation of a computer system that can be included as one or more components of a system or method for manipulating tissue during a surgical procedure as disclosed herein.

DETAILED DESCRIPTION

[0045] Aspects of the present disclosure relate to an apparatus and method for determining positional information of a steerable assembly within a body, utilizing a plurality of fiber bragg grating (FBG) sensors arranged along a length of an elongated fiber. An apparatus includes a polymeric tube containing the elongated fiber and the plurality of FBG sensors to form a sheathed fiber bragg grating sensor assembly, with the tube having a sealed distal tube end. A reference point of the elongated fiber is configured to be fixed to an external support structure, and a portion of the sheathed FBG sensor assembly is insertable through a passage defined by the steerable assembly within the body. A surgical system may utilize the foregoing apparatus and steerable assembly. A FBG driver/detector may be used to receive reflected light signals and used to determine one or more of force, strain, or shape of the plurality of FBG sensors. A method includes fixing a reference point of an elongated fiber to an external support structure, inserting a distal portion of the elongated fiber with multiple FBG sensors into a passage of a steerable assembly, and recording a configuration of the elongated fiber utilizing the FBG sensors when at least a portion of the elongated fiber is received by the passage, when the steerable assembly is arranged within a body.

[0046] The disclosure relies upon use of FBG sensors, in which an optical fiber has fixed sensing points along its length that permit determination of the shape of the fiber in three dimensions. FIG. 1 schematically illustrates an optical fiber 11 having multiple FBG sensors 14 along its length, wherein each FBG sensor 14 serves as an individual sensing point. In use, the optical fiber 11 including FBG sensors 14 is received by an elongated structure (e.g., 152 in FIG. 3, of a surgical instrument, a borescope, or the like) that is subject to being advanced into a body (110 in FIG. 3, either an animal body or non-animal body). A FBG detector (e.g., 150 in FIG. 3) can record x, y, and z coordinates of the sensor 14 at each sensing point along the optical fiber 11 with respect to a reference point (e.g., an initial or first sensing point) along the optical fiber 11. The reference point is fixed to an external support structure (e.g., a surgical/support table ( 131 in FIG. 3)) at a specified distance of a base of a robotic arm, or affixed directly to a robotic arm base (e.g., 132 in FIG. 3), such that the data obtained from the FBG detector may provide positional information of the elongated structure relative to the robotic arm base.

[0047] Embodiments of the present disclosure permit determination of positional information of a steerable assembly arranged within a body to be analyzed, wherein the body may comprise an animal (e.g., human) body or a non-animal body, and the steerable assembly may be moved by either pushing from a base portion or magnetically pulled via a tip portion thereof using a magnetic force generator external to the body to be analyzed. The steerable assembly may include an optical fiber and a plurality of FBG sensors as described herein.

[0048] In certain embodiments, an elongated structure such as a surgical instrument may be steered via pushing, by exploiting asymmetric forces on an instrument (e.g., needle) tip during insertion. As an instrument tip is pushed forward through tissue, it also moves slightly sideways, motivated by the radial component of the force acting on the tip. The magnitude of this sideways movement depends on the tip geometry, tip stiffness, tissue stiffness, bevel angle, and other properties of the instrument tip-tissue interactions. The instrument (or an associated tubular structure connected to the needle) is rotated at the base to control the orientation of the tip, thus rotating the direction of the asymmetric force and permitting the trajectory of the instrument tip to be controlled.

[0049] In certain embodiments, an elongated body may constitute a surgical instrument having a magnetically responsive tip and may be steered via magnetic pulling, by being used in conjunction with an instrument needle steering apparatus and method that alters strength and/or position of at least one magnetic field source (e.g., generated by one or more end effectors such as one or more robotic arm(s)) external to an animal body to interact with the instrument tip inserted into the animal body to effectuate movement of the instrument within the animal body. A conventional elongated structure (e.g., shaft) of the surgical instrument may be replaced by an elastic shaft that is not load-bearing. By pulling the instrument tip through tissue using externally applied magnetic forces instead of pushing at the base of a load-bearing shaft supporting a needle, any concern of shaft buckling is eliminated by avoiding formation of compression stresses in the shaft. Additional details regarding magnetic pulling of a surgical instrument through tissue are disclosed in International Publication No. WO 2021/108690 A1 , which is hereby incorporated by reference herein.

[0050] In certain embodiments, a steerable assembly may include a passage configured to deliver a surgical clip to a location within a body. An exemplary surgical clip may include one or more premagnetized portions (e.g., embodied in as a permanent magnet or a ferroelectric magnet), and well as a grasping or affixing element (such as microforceps, a clamp, or the like). A surgical clip may include a tubular body structure containing a yoke (configured to engage a control wire), a tension member (configured to outwardly bias arms of a grasping element), and/or an optional extension member intermediately coupled between the yoke and the tension member. A surgical clip may be affixed to tissue within a body, wherein at least one magnetic field source arranged external to the body is used to interact with premagnetized material of the surgical clip and thereby alter position of one or more surgical clips affixed to the tissue. A robotic actuator (e.g., an articulating robotic arm) may be moved as desired around an animal body to adjust the magnetic field strength and magnetic field direction applied to surgical clips. The magnetic field source external to the animal body may comprise one or more paramagnetic, ferromagnetic, and/or electromagnetic materials. Magnetic field strength and direction may be calculated based on a surgeon’s desired manipulation of target tissue.

[0051] When a magnetic field is applied to at least one premagnetized element of a surgical clip (whether by a magnetic field source external to the animal body, and/or by a premagnetized element of a surgical instrument within the animal body), the premagnetized material weight is pulled in the direction of the applied magnetic field. Since the grasping or affixing element is coupled with tissue within the animal body, application of a magnetic field causes the tissue to be locally displaced, which may provide access and/or visibility to a surgeon to perform a desired surgical procedure. [0052] A robotic actuator may be controlled by user manipulation of a user input device, which may have one or more associated actuators to supply haptic feedback to the user through the user input device (e.g., proportional to one or more of magnetic field strength, magnetic field direction, surgical clip strain, and tissue displacement. One example of a user input device is a joystick, which may be provided in single or dual forms, optionally augmented with various items such as triggers, buttons, dials, and the like. A camera and/or optical fiber associated with an endoscope may be provided within the animal body in or adjacent to a surgical field (e.g., proximate to the one or more surgical clip and/or a surgical tool) to enable visualization, such as by using one or more displays, whether in stand-alone or wearable (e.g., headset) form. In certain embodiments, movement and/or activation of at least one magnetic field source may be controlled responsive to one or more of: (i) signals received from a camera within the animal body (which may detect tissue displacement), (ii) detected surgical clip strain (such as may be detected with a strain gauge associated with the surgical clip), (iii)) detected magnetic field strength, and (iv) detected magnetic field direction.

[0053] In certain embodiments, robotic ex-situ actuation of at least one surgical clip (e.g., using a robotic arm arranged to move a magnetic field source external to a body) may be supplemented with, or replaced with, in-situ actuation using at least one premagnetized element associated with a surgical instrument, wherein the premagnetized element may be moved to alter position of one or more surgical clips. A surgical instrument may include an elongated body structure supporting at least one premagnetized element, wherein the elongated body structure may comprise one or more of a hollow tube, a catheter, an electrical conductor, a camera, and an optical fiber. In certain embodiments, in-situ actuation may be used to facilitate engagement of a magnetic surgical clip with targeted tissue, and ex-situ actuation may be used thereafter during a surgical procedure, to free up a surgical instrument for use in dissection or other operations. In certain embodiments, in-situ actuation and ex-situ actuation may be performed at different times, or may be performed simultaneously. In certain embodiments, in-situ actuation may be performed by moving a surgical instrument (e.g., a steerable surgical element) comprising at least one premagnetized element associated with an elongated structure within an animal body, wherein such actuation may be performed manually by a surgeon or aided by one or more actuators.

[0054] In use, an elongated structure of a steerable assembly is may be inserted into a body (e.g., through an incision or a pre-existing natural opening such as a mouth) and guided (optionally through use of a camera associated with the steerable assembly) to a location of interest to perform a procedure. One example of a location of interest is a site of a tumor. One or more surgical clips may be deployed through a steerable assembly once located at a tumor site. After a location of interest is attained, the elongated structure of a steerable assembly may be subject to little to no movement while a surgical procedure is performed. As a result, it may not be necessary to obtain continuous FBG sensor data and maintain an FBG sensor assembly present within the elongated structure for the entire duration of a surgical procedure. Instead, FBG sensors may be inserted into an elongated structure of a steerable assembly when the steerable assembly has reached a location of interest within a body, then positional information (e.g., of the steerable assembly and/or other items within the body located beyond the steerable assembly) may be obtained from the FBG sensors, and then the FBG sensors may be removed from the steerable assembly in order to free up one or more passages of the steerable assembly for other uses.

[0055] In certain embodiments, an elongated fiber having a plurality of FBG sensors may be inserted into a polymeric tube having a sealed distal tube end to form a sheathed FBG sensor assembly. Any suitable polymeric tube material may be used, with non-limiting examples being PTFE and/or various polyolefin materials. Such a polymeric tube prevents contact between the body and the fiber I FBG sensors, and also permits the fiber and associated FBG sensors to be re-used without requiring rigorous sterilization (or re-sterilization) procedures. In certain embodiments, an elongated fiber with multiple FBG sensors is sheathed within a polymeric tube to form a sheathed FBG sensor assembly, at least a distal portion of the sheathed FBG sensor assembly is inserted into a passage of the steerable assembly, and a configuration of the elongated fiber with the FBG sensors is recorded when the steerable assembly is arranged within a body, thereby permitting determination of location (i.e., in three dimensions) of the steerable assembly within the body. In certain embodiments, particularly if the elongated structure of the steerable assembly is magnetically responsive, the location information for the steerable assembly may be used to define a travel exclusion zone (e.g., no-travel zone) to prevent an external magnetic field source (optionally moveable via a robotic actuator such as a robotic arm) from causing a magnetic field to be applied within a specified distance and with a specified strength relative to the steerable assembly, thereby preventing undesired movement of the steerable assembly within the body that could otherwise result in tissue damage and/or interfere with performance of a surgical procedure.

[0056] In certain embodiments, a distal end of a sheathed FBG sensor assembly may be caused to extend through an aperture at an end of the passage of the steerable assembly and contact a magnetically responsive item (e.g., a magnetically responsive surgical clip) within the body, wherein the recording of configuration of the elongated fiber is performed when the distal end of the sheathed FBG sensor assembly is in contact with the magnetically responsive item. In this manner, a precise location of the magnetically responsive item within the body may be determined.

[0057] FIG. 2 schematically illustrates a surgical clip 20 (also known as a tissue anchor or a tissue clip, and including a magnetic weight 22 of premagnetized material, a coupling or tethering element 24, and a grasping or affixing element 26) arranged within a gastric cavity 33 of an animal body 30, with the grasping or affixing element 26 being attached to a portion of gastric wall tissue 32. A robotic manipulator 40 having an associated magnetic field source 52 is positioned external to the animal body 30, wherein the magnetic field source 52 is arranged to apply a magnetic field to apply an attracting force to the magnetic weight 22, thereby applying tension to the coupling element 24 and the grasping or affixing element 26 to pull the attached portion of gastric wall tissue 32 to provide access to an implement 80 (e.g., needle, cutting instrument, etc.) of an endoscopic device 70 or other surgical instrument. As shown, the endoscopic device 70 includes a flexible body structure 74 and may include multiple bores or channels 76, 77 defined therein to receive items such as a camera, an optical fiber, and/or electrical conductors, wherein the bores or channels 76, 77 may also permit therapeutic or diagnostic material to be supplied to a surgical site, or permit tissue to be removed from a surgical site. The robotic manipulator 44 may include one or more robotic arms 45, 47 and associated joints 44, 46, 48 with multiple degrees of freedom, and/or may include multiple magnetic field sources 52. Each magnetic field source 52 includes magnets 23-1 , 23-2 (e.g., permanent magnets or electromagnets), wherein in certain embodiments, the magnets 23-1 , 23-2 may be, or may be controlled to be, of the same polarity or opposing polarities. Although a gastric wall 31 and gastric cavity 33 are shown, it is to be appreciated that any embodiments herein may be used with any suitable tissue within an animal (including but not limited to human) body.

[0058] FIG. 3 schematically illustrates components of a system 100 for determining positional information of a steerable assembly having an elongated structure (e.g., a surgical instrument) 152 within an interior of a body 110 (optionally comprising an animal body, including but not limited to a human body) according to one embodiment. At lower left, an elongated structure (e.g., surgical instrument) 152 extends through an opening or incision 111 and is positioned within tissue of an animal body 110 proximate to a surgical clip (also known as a tissue clip or tissue anchor) 120 that comprises a premagnetized material 122, optionally coupled with a tether 124 or other structure. The surgical instrument comprises an elongated structure 152 terminating at a tip 180 within the animal body 110, with the tip 180 comprising one or more of a tool or other implement, a camera 184, and a premagnetized element 182, wherein any of the foregoing elements may be selectively deployed through one or more passages of the elongated structure 152 in certain embodiments. The elongated structure 152 further comprises a passage through which an optical fiber 151 with a plurality of fiber bragg grating (FBG) sensors 154 may be inserted and removed. One or more magnetic field sources that may comprise robotic actuators (e.g., robotic arms 114-1 , 114-2, such as 6- degree-of-freedom (6DOF) robotic arms and associated magnetic end effectors 112-1 , 112-2) are arranged external to the animal body 110 to apply at least one magnetic field to alter position of the surgical clip 120. The robotic actuators (e.g., robotic arms 114-1 , 114-2) are affixed to a base 132 that is fixed to a support table 131 , wherein a reference point of an optical fiber 151 of a FBG sensor assembly received by the elongated body 152 is fixed to the support table 131 at a specified distance relative to the base 132 (or directly to the base 132 in certain embodiments). The robotic actuators (e.g., robotic arms 114-1 , 114-2) may be controlled by motor drivers 116 and a processor 130 (e.g., integrated with a microcomputer in certain embodiments), wherein one or more intermediately arranged motor signal converters 117 may also be provided. Desired poses of the robotic arms 114-1 , 114-2 may be calculated by the processor 130 and supplied to the motor drivers 116 (optionally embodied in stepper motor drivers) to control movement of the robotic arms 114-1 , 114-2. Movement of one or more magnetic end effectors 112-1 , 112-2 (which may be embodied in permanent magnet materials, ferromagnetic materials, or electromagnets) may cause movement of the surgical clip 120 coupled to tissue within the animal (e.g., human) body.

[0059] In certain embodiments, a surgical clip 120 may be additionally or alternatively controlled by movement of the premagnetized element 182 of the surgical instrument 152 located within the animal body 110 proximate to the surgical clip 120. A magnetic steering and control element associated with the surgical instrument 152 may be used to control positioning (and/or applied field if the premagnetized element 182 comprises an electromagnet) of the premagnetized element 182 of the surgical instrument 152. In certain embodiments, a premagnetized implement (e.g., needle tip) 180 is associated with the elongated structure 152 of a surgical instrument and may be moved through the animal tissue 110 by magnetic pulling with the robotic manipulators 114-1 , 114-2 and magnetic effectors 112-1 , 112-2 located external to the animal body 1109, and after the premagnetized implement 180 is positioned in a surgical field, the premagnetized implement 180 may be retracted through a bore or channel (e.g., 76, 77 in FIG. 1) of the elongated structure 152, and a magnetically moveable tissue anchor 120 may be deployed through a bore or channel (e.g., 76, 77 in FIG. 1) of the elongated structure 152 into a surgical field within the animal tissue 110.

[0060] As shown in FIG. 2, a user input device 119 controllable by user manipulation is arranged to permit control of the magnetic end effectors 112-1 , 112-2. One or more feedback actuators 118 may be configured to supply haptic feedback to the user through the user input device 119 (e.g., proportional to one or more of magnetic field strength, magnetic field direction, tissue displacement, tissue density, deviation from desired trajectory, or the like). One example of a user input device 119 is a joystick, which may be provided in single or dual forms, optionally augmented with various items such as triggers, buttons, dials, and the like. A camera and/or optical fiber (coupled to camera imager 133) associated with the elongated body structure 152 may be provided within the body 110 (optionally within a surgical field for an animal body 110, such as proximate to a surgical tool at a top 180 of the elongated body 152) to enable visualization, such as by using one or more displays 148, whether in stand-alone or wearable (e.g., headset) form.

[0061] In certain embodiments, movement and/or activation of at least one magnetic field sourcel 12-1 , 112-2 may be controlled responsive to one or more of: (i) signals received from a camera 184 within the animal body (which may detect tissue displacement), (ii) detected tissue anchor strain (such as may be detected with a strain gauge associated with the anchor 120), (iii) detected magnetic field strength, and (iv) detected magnetic field direction. Magnetic field strength and/or field direction may be detected by one or more magnetic field sensors 113 arranged external to the animal body 110.

[0062] With continued reference to FIG. 2, in certain embodiments, position of the surgical instrument 152 within the animal body 110 may be estimated without continuous imaging techniques. In certain embodiments, a fiber 151 with a plurality of fiber bragg grating (FBG) sensors 154 contained within a polymeric tube (shown in FIG. 5B) in order to form a sheathed FBG sensor assembly may be inserted into an elongated structure of a steerable assembly (e.g., surgical instrument 152), whether before or after insertion the steerable assembly 152 is within tissue 110 of an animal body. Light signals may be supplied to FBG sensors 154 by an FBG driver/detector 150 arranged external to the animal body 110. Reflected light signals received by the FBG driver/detector 150 may be used to determine one or more of force, strain, or shape of the sheathed FBG sensor assembly received by the elongated structure 152, and recorded and used to determine positional of the elongated structure 152. A reference point (e.g., 149) of the FBG sensor assembly is fixed relative to the support table 131 and/or base 132 to which the robotic actuators (e.g., robotic arms 114-1 , 114-2) are affixed. The support table 131 may also be used to support the body 110 into which the elongated body structure 152 of the steerable assembly (e.g., surgical instrument) is inserted. In certain embodiments, a distal end of a sheathed FBG sensor assembly (incorporating the fiber 151 and FBG sensors 154) is extended (e.g., by pushing) through an aperture at an end of the passage defined by the steerable assembly 152 to contact a surgical clip 120 (or other magnetically responsive item) within the body 110, wherein the recording of the configuration of the FBG sensor assembly (including fiber 151 and FBG sensors 154) is performed when the distal end of the sheathed FBG sensor assembly is in contact with the magnetically responsive item.

[0063] In certain embodiments, a three-dimensional (3D) model of the body 110 (e.g., tissue of an animal body) is generated before a steerable assembly including elongated structure (e.g., surgical instrument) 152 is supplied to tissue of the animal body 110. Such a 3D model may be generated by any suitable imaging device, such as a MRI, CT, ultrasound, fluoroscopy, or other imaging device. The 3D model, optionally received via a network interface 144 and/or generated from 3D model input data 142 as part of a 3D model interaction subsystem 141 , may be stored to memory 146 accessible to at least one processor 130, in preparation for receiving positional information of a steerable assembly (received from the 151 fiber and FBG sensors 154 inserted into the elongated structure 152) for superimposition onto the 3D model.

[0064] In certain embodiments, recording of directionality of a magnetic field applied to the elongated body 152 in the animal body 110 comprises recording control signals supplied to the stepper motor drivers 116 coupled with the robotic manipulators 114-1 , 114-2 configured to adjust position of magnetic end effectors 112-1 , 112-1 configured to apply one or more magnetic fields - whether to a surgical clip 120 or to a tip 180 of the elongated structure. In certain embodiments, recording of directionality of the magnetic field may comprise, or be supplemented by, collecting signals received from one or more magnetic field sensors 106. In certain embodiments, one or more magnetic field sensors106 may be positioned proximate to the body 110 into which the elongated structure 152 is inserted.

[0065] In certain embodiments, a condition indicative of respiration rate and/or respiration amplitude of an animal body 110 may be sensed (e.g., using respiration sensors 109 and/or a ventilator or one or more chest sensors contacting the animal body 110), and responsive to the such sensing, a 3D model of the animal body 110 (storable in memory 146) may be updated, and/or position of the magnetic end effectors 114-1 , 114-2 may be adjusted. If the body 110 comprises an animal body arranged in a lying position, the foregoing control scheme may be used to maintain constant distance in the vertical direction between the tissue of the animal body 110 and the magnetic end effectors 114-2, 114-2 so that a constant magnetic force is applied (i) on a premagnetized needle at a tip 180 of the elongated structure 152, or (ii) on one or more surgical clips 120.

[0066] In certain embodiments, motion capture tags 115 may be provided on the body 110, and a motion capture sensor 107 may be used to establish position of the body 110. If a position or orientation of the body 110 should change, then a 3D model of the body (e.g., storable in memory 146) may be updated accordingly.

[0067] While continuous imaging of an animal body 110 to be analyzed is not required according to methods disclosed herein, in certain embodiments a body imaging apparatus 108 external to the body 110 may be provided to periodically permit imaging of the body 110 and inserted portions of the elongated structure 152, as may be useful to confirm and/or correct positional information derived from the FBG sensors 154 and FBG driver/detector 150.

[0068] In certain embodiments, the system 100 may be configured to receive signals for movement of the robotic manipulators 114-1 , 114-2 (for determining magnetic field direction) and processing the signals for forwarding to a computer processor 130 for superimposition of 3D trajectory of the elongated structure 152 (e.g., optionally embodied in a surgical instrument) on a previously generated 3D model of tissue of an animal body 110 into which the elongated structure 152 is inserted.

[0069] As noted previously herein, a reference point (e.g., 149) of an elongated fiber 151 of a FBG sensor assembly is configured to be fixed to an external support structure (e.g., base 132 or support table 131) while at least a portion of a FBG sensor assembly (e.g., sheathed in a polymeric tube such as shown in FIGS. 5B-5C) is inserted into and/or through a passage defined by an elongated structure 152 of a steerable assembly into an animal body 110. In certain embodiments, a reference point 149 of the elongated fiber 151 (with the reference point 149 optionally positioned at or near a proximal end of the elongated fiber 151) is configured to be fixed to an external support structure (e.g., support table 131) at a specified distance (e.g., 0 to 20 cm, or 0 to 10 cm, or any other suitable distance) relative to the base 132 of one or more robotic arms 114- 1 , 114-2 that are configured to manipulate one or more magnetically responsive elements 112-1 , 112-2 within the animal body 110. In certain embodiments, an external support structure 131 comprises a surgical operation table, optionally wherein the same table may be used to support an animal body 110 (e.g., a patient) to be treated with a surgical procedure. In certain embodiments, the external support structure comprises a support table 131 to which the base 132 of the robotic arms 114-1 , 114-2 is mounted. In certain embodiments, an external support structure comprises the base 132 of the robotic arms 114-1 , 114-2, and the reference point (e.g., 149) of the elongated fiber 151 is configured to be fixed directly to the base 132.

[0070] In certain embodiments, a FBG sensor assembly comprises a plurality of FBG sensors arranged between a distal tip of the optical fiber (insertable into a body) and a reference point, optionally wherein the optical fiber may be devoid of FBG sensors between a reference point and a proximal end of the fiber. In certain embodiments, a FBG sensor assembly comprises a distal portion and a medial portion, and the distal portion of the elongated fiber comprises a greater number of FBG sensors per unit length (e.g., a greater spatial or linear density of FBG sensors) than the medial portion of the elongated fiber.

[0071] FIG. 4 is a top plan view of an elongated optical fiber 15T having a plurality of FBG sensors 154A-154H coupled with a fiber bragg grating sensor (FBGS) control box 150’, with a reference point 149’ of the optical fiber being fixed relative to a surgery operation table 131’. As shown, the optical fiber 15T has a non-linear shape between the reference point 149’ and a distal end (or tip) 191 of the fiber. A proximal end 192 of the optical fiber 151 is received by the FBGS control box 150’, which includes an FBG driver/detector (e.g., 150 in FIG. 3) as described previously herein. When optical signals are propagated by the FBGS control box 150’ to FBG sensors 154A-154H along the optical fiber 151’ and reflected back to the FBGS control box 150’, the resulting signals received by the FBGS control box 150’ may be processed to provide positional information regarding the optical fiber 151’. Although only eight FBG sensors 154A- 154H are shown in FIG. 4, it is to be appreciated that any suitable number of FBG sensors and spacing therebetween may be provided. In certain embodiments, individual FBG sensors 154A-154H may have lengths in a range of 1 nm to 0.5 cm, and spacing between FBG sensors may be in a range of O.may be An FBG assembly including the optical fiber 151’ and FBG sensors 154A-154H may be received by an elongated structure (e.g., 152 in FIG. 3) of a steerable assembly as described previously herein, with such steerable assembly being insertable into an animal body (e.g., 110 in FIG. 3). Since the reference point 149’ of the optical fiber 15T is fixed (e.g., to the surgery operation table 131’) and may be known relative to a base (e.g., 132 in FIG. 3) of at least one robotic actuator arm (not shown) couplable to the table 13T, positional information of a steerable assembly (incorporating the optical fiber 151’ and FBG sensors 154A-154H relative to the robotic actuator arm may be determined. In certain embodiments, an animal body into which a steerable assembly containing the sensor assembly (e.g., optical fiber 151’ and FBG sensors 154A-154H, which may be sheathed by a polymeric tube within the elongated body (e.g., 152 in FIG. 3) of a steerable assembly) may also be supported by the surgery operation table 13T.

[0072] FIG. 5A is a side view of an optical fiber assembly 290 including an optical fiber 251 having a plurality of FBG sensors (e.g., 154A-154H as shown in FIG. 4) according to one embodiment, with a proximal end 292 of the optical fiber 251 extending from an optical fiber connector 298, and a distal end 291 of the optical fiber 251 being devoid of a connector. The optical fiber 251 may have any suitable length (as represented by the illustrated symbolic break) and may include any suitable number of FBG sensors (e.g., at least at least five, at least ten, at least twenty, at least thirty, at least forty, or more).

[0073] FIG. 5B is a side view of an optical fiber assembly 290A including an optical fiber 25T (similar to the optical fiber 251 shown in FIG. 5A but having a reduced length for illustration purposes) having a plurality of FBG sensors (e.g., 154A-154H as shown in FIG. 4) according to one embodiment. The optical fiber assembly 290A is shown proximate to a polymeric tube 285 having an open proximal end 288, a closed distal end 287, and a hollow bore 286 configured to receive the optical fiber 25T and associated FBG sensors, with the polymeric tube 285 being suitable to form a sheath for the optical fiber 25T. A proximal end 292’ of the optical fiber 25T extends from an optical fiber connector 298, with a distal end 29T being devoid of a connector.

[0074] FIG. 5C is a side view of a sheathed FBG sensor assembly 290A’ including the optical fiber 25T and associated FBG sensors of FIG. 5A received within the polymeric tube 285 as shown in FIG. 5B, with the closed distal end 287 of the polymeric tube 285 being proximate to the distal end 29T of the optical fiber 25T, and with the open proximal end 288 of the polymeric tube 285 being proximate to the proximal end 292’ of the optical fiber 25T. In certain embodiments, the proximal end 288 of the polymeric tube 285 may be mechanically or adhesively connected to the optical fiber connector 298.

[0075] FIG. 6 schematically illustrates an optical fiber assembly 390 including an optical fiber 351 having a plurality of FBG sensors 354A-354AF, with a proximal end 392 of the optical fiber 351 being coupled to an optical fiber connector 398, and with a distal end 391 of the optical fiber 351 being devoid of a connector. A proximal section 301 of the optical fiber 351 embodies a first non-sensorized part (devoid of FBG sensors, optionally having a length of 80 cm) between the optical connector 398 and a fixed reference point 349 (which may itself include a FBG sensor). A medial section 302 of the optical fiber 351 (including a first medial segment 302A and a second medial segment 302B) embodies a sensorized part (optionally having a length of 198 cm) extending from the reference point 349 through a first FBG sensor 354A to a last (thirty-second) FBG sensor 354AF. Of the sensorized part embodied in the medial section 302, the first medial segment 302A (optionally 187.5 cm in length) may have FBG sensors (354A- 354Y) with a different inter-sensor spacing than the second medial segment 302GB (optionally 10.5 cm in length). In certain embodiments, inter-sensor spacing of FBG sensors (e.g., including FBG sensors 354AE and 354AF) in the second medial segment 302B may be smaller (e.g., 1 .5 cm between sensors) than inter-sensor spacing of FBG sensors (e.g., including FBG sensors 354A-354Y) in the first medial segment 302A (e.g., 7.5 cm between sensors), to provide more sensory information and greater resolution in the second medial segment 302B closer to the distal end 391 of the optical fiber 351 . Any desired number and spacing of FBG sensors may be provided in the medial section 302, including in the first medial segment 302A and second medial segment 302B thereof. A distal section 303 of the optical fiber 351 may embody a second non- sensorized part near the distal end 391 . Although not shown in FIG. 6, the optical fiber connector 398 may be coupled to one or more FBG driver/detector units (e.g., 150’ in FIG. 4 or 150 in FIG. 3). In certain embodiments, multiple optical fibers 351 may be provided, each with a corresponding FBG sensor array. In certain embodiments, FBG arrays of different optical fibers may be staggered or dedicated to different regions along a length of an optical fiber assembly (e.g., with a first optical fiber having a first FBG array in a first region along a length of an optical fiber assembly, a second optical fiber having a second FBG array in a second region along a length of an optical fiber assembly, and so on, wherein any suitable number of 2, 3, 4, 5, or more optical fibers may be provided).

[0076] FIG. 7 is a perspective view of a robotic arm 414 incorporating magnets 413- 1 , 413-2 (e.g., permanent magnets or electromagnets) to serve as an end effector 412 to effectuate movement of a steerable assembly including a magnetic needle within tissue of an animal body according to certain embodiments. In certain embodiments, the magnets 413-1 , 413-2 may be, or may be controlled to be, of the same polarity or opposing polarities. The robotic arm 414 is mountable to a support surface 460 and includes multiple joints 465-469 to provide numerous degrees of freedom for movement of the robotic arm 414 relative to tissue of an animal body in order to effectuate movement of an implement including a premagnetized portion (e.g., needle tip) of a surgical instrument within tissue of the animal body, and/or to effectuate movement of a surgical clip (not shown) within the animal body. In certain embodiments, the robotic arm 214 may be used initially to move an implement within tissue of the animal body, and thereafter to manipulate a surgical clip.

[0077] FIG. 8 is a schematic view illustration of a portion of a fiber bragg grating (FBG) sensor array 452 that may be utilized with a system for determining position of a steerable assembly (e.g., a surgical instrument or borescope) within a body according to certain embodiments. The FBG sensor array 452 is embodied in an optical fiber 451 having a core 453 surrounded by cladding 455. A portion of the core 453 constitutes an index modulation region 454 in which an index of refraction of glass material of the core 453 periodically varies. When an input signal 456A (having a propagating core mode) is transmitted through the core 453 and reaches the index modulation region 454, one spectral portion of the input signal is reflected to produce a reflected signal 456C, while another spectral portion is transmitted through the index modulation region 454 to provide a transmitted signal 456B. The reflected signal 456C may be detected by a light detector associated with a FBG driver/detector unit (not shown), and analyzed to determine one or more of force, strain, or shape experienced by the FBG sensor array 452. In certain embodiments, one or more FBG sensors (or sensor arrays) may be arranged in or on an elongated body structure of a steerable assembly (e.g., as part of a sheathed FBG sensor assembly). If multiple FBG arrays are provided, then each FBG array may have an associated FBG driver/detector unit.

[0078] FIG. 9 is schematic diagram of a generalized representation of a computer system 500 that can be included as one or more components of a system or method for determining positional information of a steerable assembly within a body as disclosed herein, according to one embodiment. The computer system 500 may be adapted to execute instructions from a computer-readable medium to perform these and/or any of the functions or processing described herein.

[0079] The computer system 500 may include a set of instructions that may be executed to program and configure programmable digital signal processing circuits for supporting scaling of supported communications services. The computer system 500 may be connected (e.g., networked) to other machines in a local area network (LAN), an intranet, an extranet, or the Internet. While only a single device is illustrated, the term "device" shall also be taken to include any collection of devices that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. The computer system 500 may be a circuit or circuits included in an electronic board or card, such as a printed circuit board (PCB), a server, a personal computer, a desktop computer, a laptop computer, a personal digital assistant (PDA), a computing pad, a mobile device, or any other device, and may represent, for example, a server or a user's computer.

[0080] The computer system 500 in this embodiment includes a processing device or processor 502, a main memory 504 (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM), such as synchronous DRAM (SDRAM), etc.), and a static memory 506 (e.g., flash memory, static random access memory (SRAM), etc.), which may communicate with each other via a data bus 508. Alternatively, the processing device 502 may be connected to the main memory 504 and/or static memory 506 directly or via some other connectivity means. The processing device 502 may be a controller, and the main memory 504 or static memory 506 may be any type of memory.

[0081] The processing device 502 represents one or more general-purpose processing devices, such as a microprocessor, central processing unit (CPU), or the like. In certain embodiments, the processing device 502 may be a complex instruction set computing (CISC) microprocessor, a reduced instruction set computing (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, a processor implementing other instruction sets, or other processors implementing a combination of instruction sets. The processing device 502 is configured to execute processing logic in instructions for performing the operations and steps discussed herein.

[0082] The computer system 500 may further include a network interface device 510. The computer system 500 may additionally include at least one input 512, configured to receive input and selections to be communicated to the computer system 500 when executing instructions. The computer system 500 also may include an output 514, including but not limited to a display, a video display unit (e.g., a liquid crystal display (LCD) or a cathode ray tube (CRT)), an alphanumeric input device (e.g., a keyboard), and/or a cursor control device (e.g., a mouse).

[0083] The computer system 500 may or may not include a data storage device that includes instructions 516 stored in a computer readable medium 518. The instructions 516 may also reside, completely or at least partially, within the main memory 504 and/or within the processing device 502 during execution thereof by the computer system 500, the main memory 504 and the processing device 502 also constituting computer readable medium. The instructions 516 may further be transmitted or received over a network 520 via the network interface device 510.

[0084] While the computer readable medium 518 is shown in an embodiment to be a single medium, the term "computer-readable medium" should be taken to include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of instructions. The term "computer readable medium" shall also be taken to include any medium that is capable of storing, encoding, or carrying a set of instructions for execution by the processing device and that cause the processing device to perform any one or more of the methodologies of the embodiments disclosed herein. The term "computer readable medium" shall accordingly be taken to include, but not be limited to, solid-state memories, an optical medium, and/or a magnetic medium.

[0085] Those skilled in the art will recognize improvements and modifications to the preferred embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow. Any of the various features and elements as disclosed herein may be combined with one or more other disclosed features and elements unless indicated to the contrary herein.

Claims

Claims What is claimed is:

1. An apparatus for determining positional information of a steerable assembly within a body, the apparatus comprising: a plurality of fiber bragg grating sensors arranged along a length of an elongated fiber; and a polymeric tube containing the elongated fiber and the plurality of fiber bragg grating sensors to form a sheathed fiber bragg grating sensor assembly, the polymeric tube comprising a sealed distal tube end, wherein a distal end of the elongated fiber is arranged proximate to the sealed distal tube end, and at least a portion of the elongated fiber is affixed to the polymeric tube; wherein at least a portion of the sheathed fiber bragg grating sensor assembly is configured to be inserted through a passage defined by the steerable assembly when the steerable assembly is within the body; and wherein a reference point of the elongated fiber is configured to be fixed to an external support structure at a specified distance relative to a base of a robotic arm that is configured to manipulate one or more magnetically responsive elements within the body.

2. The apparatus of claim 1 , wherein the sheathed fiber bragg grating sensor assembly comprises a distal portion and a medial portion, and the distal portion comprises a greater number of fiber bragg grating sensors per unit length of the elongated fiber than the medial portion.

3. The apparatus of claim 1 , wherein the polymeric tube is configured to be disposable, with the at least a portion of the elongated fiber being removably affixed to the polymeric tube to permit the elongated fiber to be removed from the polymeric tube and inserted into another polymeric tube for re-use.

4. The apparatus of claim 1 , wherein the external support structure comprises the base of the robotic arm, and the reference point of the elongated fiber is configured to be fixed directly to the base of the robotic arm.

5. The apparatus of claim 1 , wherein the external support structure comprises a table to which the base of the robotic arm is mounted.

6. The apparatus of claim 1 , wherein the external support structure comprises a table to which the base of the robotic arm is mounted.

7. A surgical system comprising the apparatus of claim 1 and the steerable assembly, wherein: the steerable assembly comprises an elongated body structure including a proximal end configured to be inserted into the body, the proximal end comprising an aperture arranged at an end of the passage defined by the steerable assembly; and a proximal end of the sheathed fiber bragg grating sensor assembly is configured to extend through the aperture.

8. The surgical system of claim 7, wherein the elongated body structure comprises a plurality of passages configured to permit delivery or use of one or more of a camera, a grasping tool, a cutting tool, a surgical clip, and a therapeutic agent.

9. The surgical system of claim 7, further comprising the robotic arm, wherein the robotic arm comprises or more magnets arranged external to the body.

10. The surgical system of claim 7, further comprising a fiber bragg grating driver/detector arranged external to the body, wherein the fiber bragg grating driver/detector is configured to receive reflected light signals useable to determine one or more of force, strain, or shape of the plurality of fiber bragg grating sensors.

11 . The surgical system of claim 1 , wherein the body comprises an animal or human body.

12. A method for determining positional information of a steerable assembly within a body, the method comprising: fixing a reference point of an elongated fiber to an external support structure, the elongated fiber comprising a plurality of fiber bragg grating sensors arranged along a length of the elongated fiber; inserting a distal portion of the elongated fiber including at least some fiber bragg grating sensors of the plurality of fiber bragg grating sensors into a passage defined by the steerable assembly; and recording a configuration of the elongated fiber utilizing the at least some fiber bragg grating sensors when some or all of the distal portion of the elongated fiber is received by the passage, and when the steerable assembly is arranged within the body.

13. The method of claim 12, wherein the distal portion of the elongated fiber including the at least some fiber bragg grating sensors is arranged within a polymeric tube to form a sheathed fiber bragg grating sensor assembly.

14. The method of claim 13, wherein the polymeric tube is configured to be disposable, with the at least a portion of the elongated fiber being removably affixed to the polymeric tube to permit the elongated fiber to be removed from the polymeric tube and inserted into another polymeric tube for re-use.

15. The method of claim 13, further comprising causing a distal end of the sheathed fiber bragg grating sensor assembly to extend through an aperture at an end of the passage defined by the steerable assembly and contact a magnetically responsive item within the body, wherein the recording of the configuration of the elongated fiber is performed when the distal end of the sheathed fiber bragg grating sensor assembly is in contact with the magnetically responsive item.

16. The method of claim 15, wherein the magnetically responsive item comprises a magnetically responsive surgical clip.

17. The method of claim 13, wherein the sheathed fiber bragg grating sensor assembly comprises a distal portion and a medial portion, and the distal portion comprises a greater number of fiber bragg grating sensors per unit length of the elongated fiber than the medial portion.

18. The method of claim 12, wherein the fixing of the reference point of the elongated fiber is performed at a specified distance relative to a base of a robotic arm that is configured to manipulate one or more magnetically responsive elements within the body.

19. The method of claim 18, wherein the specified distance is in a range of 0 to 20 cm.

20. The method of claim 12, wherein the external support structure comprises a base of a robotic arm that is configured to manipulate one or more magnetically responsive elements within the body, and the reference point of the elongated fiber is fixed directly to the base of the robotic arm.

21 . The method of claim 12, wherein the steerable assembly comprises an elongated body structure that defines a plurality of passages configured to permit delivery or use of one or more of a camera, a grasping tool, a cutting tool, a surgical clip, and a therapeutic agent.

22. The method of claim 12, further comprising use of a fiber bragg grating driver/detector arranged external to the body to receive reflected light signals and to determine one or more of force, strain, or shape of the plurality of fiber bragg grating sensors.

23. The method of claim 12, wherein the body comprises an animal or human body.