Tendon-rigidizing apparatuses

Abstract

Described herein are rigidizing apparatuses (e.g., devices, system, etc.) and methods of using them that may rigidize over a long length of the device from a highly flexible and maneuverable configuration to a highly rigid configuration, while maintaining a relatively small diameter. In particular, described herein are apparatuses and methods including pressure-compression tendons that may be used in conjunction with a second rigidizing layer to enhance stiffness, particularly at the distal end region.

Description

TENDON-RIGIDIZING APPARATUSES CLAIM OF PRIORITY

[0001] This patent application claims priority to U.S. provisional patent application no. 63 / 610,968, titled “TENDON-RIGIDIZING APPARATUSES,” and filed on December 15, 2023, herein incorporated by reference in its entirety. BACKGROUND

[0002] Surgical devices may include elongate, sometimes tubular structures that include catheters, sheaths, scopes (e.g., endoscopes), wires, overtubes, cannulas, trocars or laparoscopic instruments. The devices can function as a separate add-on device or can be integrated into the body of devices. These devices can be combined with other devices into more complex systems, including nested systems. The devices are inserted into the body so as to access regions within the body, including in some cases forming passages for additional diagnostic and therapeutic medical devices. In some cases, it may be beneficial for such elongate medical devices to be rigid or flexible, and in many cases, it would be particularly beneficial for these devices to be changed from a flexible configuration into a rigid configuration. There are significant advantages to both highly flexible devices as well as significant advantages to rigid devices, however each also has disadvantages. Flexible endoscopes and catheters rely on reaction forces generated by pushing against the tissue of the body cavity being explored to navigate around corners or bends in the anatomy. Flexibility may be problematic when navigating through body regions having highly tortuous passages, areas that are comparatively open, or passages of varying (or large) luminal diameter, where it may be difficult to make reliable contact with the outer diameter of the tube. Further, highly flexible tubes may buckle, prolapse, loop, or may have trouble supporting additional tools or devices. Highly rigid tubes may be difficult to navigate within the body and can cause damage to the anatomy if they are forced through certain anatomical pathways.

[0003] Thus, it may be beneficial to provide apparatuses that can transition between a rigid configuration and a flexible configuration on demand. In particular, it would be beneficial to provide rigidizing apparatuses in which the rigid configuration is sufficiently rigid so that it resists changing shape even when substantial force is applied against the rigid configuration. Ideally, such apparatuses would be highly flexible in the flexible configuration, to allow them to assume curved and / or bent configurations (including configurations having a small radius of curvature) without requiring the application of a - 1 - SG Docket No.: 13668-727.600significant amount of force. Such devices may provide safe, efficient, and precise access to otherwise difficult to reach anatomical locations, and may enable more efficacious therapies once these anatomical locations have been reached.

[0004] Described herein are apparatuses and methods that may address these needs. SUMMARY OF THE DISCLOSURE

[0005] Described herein are rigidizing apparatuses (e.g., devices, system, etc.) and methods of using them that may rigidize over a long length of the device from a highly flexible and maneuverable configuration to a highly rigid configuration. In particular, described herein are apparatuses and methods including pressure-compression tendons.

[0006] A rigidizing device including a plurality of pressure-compression tendons may include: an elongate flexible tube extending in a proximal to distal length; a plurality of lengths of pressure-compression tendons extending in a primarily lengthwise orientation along the elongate flexible tube; a compression layer configured to compress the plurality of lengths of pressure-compression tendons against the elongate flexible tube when pressure is applied, wherein the rigidizing device is configured to change between rigid and flexible states by the application of or release of the pressure. Any of these apparatuses may include an inlet that is configured to apply pressure to compress the compression layer against the plurality of lengths of the pressure-compression tendons. The flexible tube may be an inner support tube.

[0007] In any of these rigidizing devices at least some of the lengths of pressure- compression tendons may extend proximally to a proximal end of the rigidizing device and may be configured for steering the distal end of the elongate flexible inner support tube. At least some of the lengths of pressure-compression tendons may be either unattached at their proximal end or form a loop connecting two of the length of pressure-compression tendons. The plurality of lengths of pressure-compression tendons may comprise a steering sub-set of tendons extending proximally to a proximal end of the rigidizing device and are configured for steering the distal end of the elongate flexible inner support tube, and further wherein the plurality of lengths of pressure-compression tendons comprises a non-steering subset of tendons that are either unattached at their proximal end or that form a loop connecting two of the length of pressure-compression tendons.

[0008] Any of these apparatuses may include a set of steering tendons extending along the proximal to distal length. The steering (or steering / actuating) tendons may be a subset of the pressure-compression tendons, or they may be separate from the pressure-compression tendons. - 2 - SG Docket No.: 13668-727.600

[0009] The lengths of pressure-compression tendons may be radially spaced apart from each other along the proximal to distal length of the elongate flexible inner support tube. The elongate flexible inner support tube may be an inner coil-wound tube. In some examples the elongate flexible inner support tube is a laser-cut hypotube.

[0010] The compression layer may be configured to push radially outwards, radially inwards, or both. For example, the compression layer may comprise a bladder configured to receive a positive pressure to expand and compress the plurality of lengths of pressure- compression tendons against the elongate flexible inner support tube. The compression layer may be configured to receive a negative pressure to compress the plurality of lengths of pressure-compression tendons against the elongate flexible tube. The lengths of pressure- compression tendons may be within a plurality of guides / tubes along the length that are open periodically (e.g., every x mm, where x is between about 0.5 mm and 5 mm or more, between about 0.5 mm and 4.5 mm or more, between about 0.5 mm and 5 mm or more, etc.) to expose the tendon.

[0011] The lengths of pressure-compression tendons may be blunted (e.g., capped) at their proximal ends. In some examples the pressure-compression tendons may be at least partially contained (e.g., in some cases the ends of the pressure-compression tendons may be contained) within a tube or channel that may allow them to slide within the channel as the device bends, while remaining within the channel. The lengths of pressure-compression tendons may be secured to the elongate flexible tube by a sheath. As used herein, a sheath may generically refer to a structure that secure the tendon in a particular radial orientation, while allowing the tendon to slide axially in the flexible configuration; in some cases, the sheath may be compressed to prevent the tendon from sliding in the rigid configuration. The sheath may comprise of a material having any appropriate durometer; for example, in some cases the sheath may have a durometer of 60A or less on the Shore A scale. In some examples the sheath comprises a braid. The plurality of lengths of pressure-compression tendons may comprise between 4 and 24 lengths of pressure-compression tendons. Thus, the pressure-compression tendons may be unattached at the proximal end and / or the distal end and / or may be continuous (e.g., forming a loop repeating, typically non-overlapping pattern). The pressure-compression tendons may be contained within one or more channels. In some examples the pressure-compression tendons may be held within a tube or plurality of tubes; portions of the pressure-compression tendons may be outside of the tube(s).

[0012] Any of these devices may include an elongate flexible outer support tube extending in the proximal to distal length over the elongate flexible inner support tube, the plurality of lengths of pressure-compression tendons, and the compression layer. - 3 - SG Docket No.: 13668-727.600

[0013] For example, a rigidizing device may include: an elongate body comprising a support layer; a proximal region of the elongate body having a rigidizing layer comprising a plurality of strand lengths that cross over each other; a distal region of the elongate body comprising a plurality of lengths of pressure-compression tendons extending proximally in a long axis of the elongate body; and a compression layer configured to receive positive and / or negative pressure to rigidize the elongate body by driving the rigidizing layer against the support layer, and by preventing or limiting axial movement of the plurality of lengths of pressure-compression tendons, wherein the rigidizing device is configured to change between a flexible configuration and a rigid configuration.

[0014] The plurality of strand lengths may cross over (and under) each other cross at braid angle (e.g., an angle between the stands relative to the long axis of the device) of greater than about 5 degrees (e.g., greater than about 6 degrees, greater than about 7 degrees, greater than about 8 degrees, greater than about 9 degrees, greater than about 10 degrees, greater than about 11 degrees, greater than about 12 degrees, greater than about 13 degrees, greater than about 14 degrees, greater than about 15 degrees, greater than about 16 degrees, etc.) relative to a longitudinal axis of the flexible tube. In contrast, the plurality of lengths of pressure-compression tendons may extend proximally in the axis of the elongate body approximately parallel to the length of the elongate body (e.g., within + / -5 degrees relative to the long axis, + / - 4 degrees relative to the long axis, + / - 3 degrees relative to the long axis, + / - 2 degrees relative to the long axis, + / - 1 degrees relative to the long axis).

[0015] The compression layer (e.g., bladder) may extend along both the proximal region and the distal region, and may actuate rigidizing of both regions by limiting movement of both the pressure-compression tendons and the plurality of strand lengths. The compression layer may comprise a bladder layer; in some cases, the compression layer is an out-and-back bladder that is inverted over itself.

[0016] At least some of the lengths of pressure-compression tendons may extend proximally to a proximal end of the rigidizing device and may be configured for steering the distal end of the elongate flexible inner support tube (e.g., may be part of a steering subset of the tendons). In some cases, the plurality of lengths of pressure-compression tendons comprise a sub-set of tendons comprising steering tendons that extend proximally to a proximal end of the rigidizing device and are configured for steering the distal region of the elongate flexible inner support tube.

[0017] The rigidizing device of claim 1, wherein the lengths of pressure-compression tendons are unattached at their proximal ends. In some cases, even pressure-compression tendons that are not steering tendons may extend into the proximal region. For example, the - 4 - SG Docket No.: 13668-727.600pressure-compression tendons may extend proximally at least partially, or in some cases fully, through the proximal region. In some cases, the pressure-compression tendons are limited to the distal region or to a region that extends partially into the proximal region (e.g., forming an overlap region with both pressure-compression tendons and the plurality of strand lengths of the rigidizing layer). Note that the plurality of strand lengths forming the rigidizing layer may be referred to herein as the second rigidizing layer. In some cases, the plurality of strand lengths may overlap with the pressure-compression tendons over the entire rigidizing length of the rigidizing device. In some cases, the plurality of strand lengths of the rigidizing layer may be excluded from the distal end region.

[0018] At least some of the lengths of pressure-compression tendons may be connected to each other at their proximal ends. The lengths of pressure-compression tendons may be radially spaced apart from each other along the proximal to distal length of the elongate flexible inner support tube. The device may include spacers (e.g., channels) for maintaining the spacing. In some cases, the pressure-compression tendons may be within a sleeve that may help maintain the pressure-compression tendons in the desired radial positions.

[0019] The support layer may comprise an inner coil-wound tube (ICWT, e.g., a polymeric material reinforced by one or more coils, such as but not limited to helically- wound coils, which may be, for example, a metallic material), and / or the support layer may comprise an outer coil-wound tube OCWT, e.g., a polymeric material reinforced by one or more coils, such as but not limited to helically-wound coils, which may be, for example, a metallic material). The apparatus may include both an inner support layer (e.g., ICWT) and an outer support layer (e.g., OCWT).

[0020] The compression layer may be configured to receive positive pressure to rigidize the elongate body and / or a negative pressure rigidize the elongate body. In some cases, the positive pressure may be applied to push the compression layer (e.g., bladder) to compress the plurality of strand lengths and tendons to limit their ability to move relative to each other and / or the other layers of the elongate body; for example, positive pressure may be applied to the compression layer on a side of the compression layer that is opposite from the plurality of strand lengths and tendons. In some cases, negative pressure may be applied to pull the compression layer (e.g., bladder) to compress the plurality of strand lengths and tendons; for example, negative pressure may be applied to the compression layer on a side of the compression layer that is the same sides as the plurality of strand lengths and tendons. In some cases, both negative and positive pressure may be applied, e.g., applying negative pressure to the same side of the compression layer as the plurality of strand lengths and - 5 - SG Docket No.: 13668-727.600tendons and applying positive pressure to a side of the compression layer that is separated from the plurality of strand lengths and tendons by the compression layer.

[0021] The lengths of pressure-compression tendons may each be held within a guide channel and / or tube extending along the long axis of the elongate body. In any of these apparatuses, the lengths of pressure-compression tendons are unattached at their proximal and distal ends.

[0022] Any number of lengths of pressure-compression tendons may be used. For example, the plurality of lengths of pressure-compression tendons may comprise between 4 and 25 lengths of pressure-compression tendons. The plurality of lengths of pressure- compression tendons may be formed of a single loop of material or a single long tendon that is bent or curved.

[0023] In some cases a rigidizing apparatus may comprise: an elongate body extending in a proximal to distal long axis; a plurality of lengths of pressure-compression tendons extending in the long axis within a distal region of the elongate body that are configured to slide axially relative to the elongate body in a flexible configuration; a rigidizing layer extending in a proximal region of the elongate body comprising a plurality of strand lengths configured to slide over each other in a flexible configuration; and a compression layer configured to rigidize the first rigidizing device by preventing the pressure-compression tendons from sliding axially and the plurality of strand lengths from sliding over each when pressure is applied against the compression layer.

[0024] Any of the apparatuses described herein may be configured to form a nested system of rigidizing devices, the apparatus further comprising a second rigidizing device configured to rigidize, wherein the second rigidizing device is nested with the first rigidizing device, and wherein the rigidizing devices are configured to translate relative to one another and to rigidize to propagate a shape along the nested system.

[0025] The rigidizing layer may extend over the elongate flexible tube within the proximal region comprises a plurality of filament lengths crossing over and under each other and configured shear relative to each other in the flexible state. At least some of the lengths of pressure-compression tendons may extend proximally to a proximal end of the rigidizing device and are configured for steering the distal end of the elongate flexible tube. In some cases, at least some of the lengths of pressure-compression tendons are either unattached at their proximal end or form a loop connecting two of the length of pressure-compression tendons. The plurality of lengths of pressure-compression tendons comprises a steering sub- set of tendons extend proximally to a proximal end of the rigidizing device and are configured for steering the distal end of the elongate flexible tube, and further wherein the - 6 - SG Docket No.: 13668-727.600plurality of lengths of pressure-compression tendons comprises a non-steering subset of tendons that are either unattached at their proximal end or that form a loop connecting two of the length of pressure-compression tendons.

[0026] The lengths of pressure-compression tendons may be held in radially spaced apart positions along the proximal to distal length of the elongate flexible inner support tube.

[0027] As mentioned, any of these apparatuses may include an inner coil-wound tube (inner support layer) and / or an outer coil-wound tube (e.g., outer support layer). The compression layer may comprise a bladder configured to apply a positive pressure. The compression layer may be configured to apply a negative pressure to compress the plurality of lengths of pressure-compression tendons against the elongate flexible tube.

[0028] The lengths of pressure-compression tendons may be within a plurality of guides / tubes along the length that are open periodically to expose the tendon. The lengths of pressure-compression tendons may be blunted or otherwise capped at their proximal ends. The lengths of pressure-compression tendons may be secured to the elongate flexible tube by a material having a durometer of 60A or less on the Shore A scale. The plurality of lengths of pressure-compression tendons may comprise between 4 and 24 lengths of pressure- compression tendons.

[0029] Also described herein are methods of rigidizing device using a lengthwise pressure-compression tendon. For example, a method may include: steering a distal end region of a rigidizing device so that the distal end region bends while in a flexible configuration, wherein the rigidizing device comprises an elongate flexible inner support tube extending in a proximal to distal length; applying pressure to compress a plurality of lengths of pressure-compression tendons that extend lengthwise along the elongate flexible inner support tube to rigidize the rigidizing device, wherein the applied pressure is maintained to maintain the rigidizing device in a rigid configuration; and releasing the pressure to convert the rigidizing device to the flexible configuration.

[0030] For example, a method may include: steering a rigidizing device so that the rigidizing device bends while in a flexible configuration, wherein the rigidizing device comprises an elongate body extending proximally to distally in a long axis, a plurality of lengths of pressure-compression tendons that extend lengthwise parallel to the long axis in a distal region of the elongate body, and a rigidizing layer extending in a proximal region of the elongate body, wherein the rigidizing layer comprises a plurality of filament lengths crossing over each other; and applying pressure so that a compression layer within the elongate body prevent or limits axial movement of the lengths of pressure-compression tendons and so that the compression layer prevents the plurality of strand lengths from sliding over each other to - 7 - SG Docket No.: 13668-727.600convert the rigidizing device to a rigid configuration; and releasing the pressure to convert the rigidizing device to the flexible configuration. The method of may include steering the distal end region using one or more of the lengths of pressure-compression tendons to steer the distal end region. In some cases, steering comprises copying the shape of an elongate device within a lumen of the rigidizing device. Any of these methods may include inserting the device into a lumen of a patient’s body. Applying pressure may comprise applying a positive pressure and / or applying a negative pressure.

[0031] Steering the distal end region may comprise using one or more of the lengths of pressure-compression tendons to steer the distal end region. In some examples, steering the distal end region may also include using a nested system of rigidizing devices that may use shape copying to sheer at least one of the rigidizing devices.

[0032] The elongate device within the lumen of the rigidizing device may comprise a rigidizing catheter, sheath, scopes (e.g., endoscopes), wire, overtube, cannula, trocar, laparoscopic instrument, or the like.

[0033] Any of these methods may include inserting the device into a lumen of a patient’s body.

[0034] Applying pressure may comprise applying a positive pressure to drive a compression layer of the rigidizing device against the plurality of lengths of pressure- compression tendons to lock the rigidizing device in the rigid configuration. For example, applying pressure may comprise applying a negative pressure to drive a compression layer of the rigidizing device against the plurality of lengths of pressure-compression tendons to lock the rigidizing device in the rigid configuration

[0035] Also described herein are hybrid devices with a first region that is rigidizable using pressure-compression tendons and a second region having mesh rigidizing layer / distal end with pressure-compression tendons. Any number of regions may be included, including two or more, three or more, etc. For example, some longitudinal regions may be rigidized by pressure-compression tendons only. Some longitudinal regions may be rigidized by both pressure-compression tendons and a rigidizing layer (e.g., a plurality of lengths of filaments that cross over each other, etc.). Some longitudinal regions may be rigidized by just a rigidizing layer, etc. In general, regions that are rigidized by pressure-compression tendons may include an arrangement in which the pressure-compression tendons do not cross over each other. The pressure-compression tendons may extend in parallel or approximately in parallel with the long axis of the apparatus. In some examples the pressure-compression tendons are at an angle relative to the long axis of the apparatus that is less than about 15 degrees (e.g., less than about 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2 degrees, etc.). - 8 - SG Docket No.: 13668-727.600

[0036] In some examples, a rigidizing device may include: an elongate body having an elongate flexible inner support tube extending in a proximal to distal length; a proximal region comprising a rigidizing layer extending over the elongate flexible inner support tube within the proximal region, a rigidizing layer comprising a plurality of filament lengths crossing over and under each other and configured shear relative to each other; a distal region comprising a plurality of lengths of pressure-compression tendons extending lengthwise. As described herein, lengthwise may include parallel or approximately parallel, e.g., 15 degrees or less, 14 degrees or less, 13 degrees or less, 12 degrees or less, 11 degrees or less, 10 degrees or less, 9 degrees or less, 8 degrees or less, 7 degrees or less, 6 degrees or less, 5 degrees or less, 4 degrees or less, 3 degrees or less, 2 degrees or less, etc., along the elongate flexible tube; a compression assembly (e.g., compression layer) configured to compress the plurality of lengths of pressure-compression tendons in the distal region against the elongate flexible inner support tube and to compress the plurality of filament lengths of the rigidizing layer against the elongate flexible inner support tube when pressure is applied, wherein the rigidizing device is configured to change between rigid and flexible states by the application of or release of the pressure; and an inlet at a proximal end of the rigidizing device that is configured to apply pressure to compress the compression layer against the plurality of lengths of the pressure-compression tendons. The compression assembly may comprise a compression layer extending along both the proximal region and the distal region. The compression assembly may comprise a first compression layer extending along the proximal region and a second compression layer extending along the distal region. The compression assembly may comprise an inflation bladder. At least some of the lengths of pressure- compression tendons may extend proximally to a proximal end of the rigidizing device and are configured for steering the distal end of the elongate flexible inner support tube.

[0037] At least some of the lengths of pressure-compression tendons may be either unattached at their proximal end or form a loop connecting two of the length of pressure- compression tendons. The plurality of lengths of pressure-compression tendons may comprise a steering sub-set of tendons extend proximally to a proximal end of the rigidizing device and are configured for steering the distal end of the elongate flexible inner support tube, and further wherein the plurality of lengths of pressure-compression tendons comprises a non-steering subset of tendons that are either unattached at their proximal end or that form a loop connecting two of the length of pressure-compression tendons.

[0038] Any of these apparatuses may include a set of steering tendons extending along the proximal to distal length. The steering (or steering / actuating) tendons may be a subset of - 9 - SG Docket No.: 13668-727.600the pressure-compression tendons, or they may be separate from the pressure-compression tendons.

[0039] The lengths of pressure-compression tendons may be radially spaced apart from each other along the proximal to distal length of the elongate flexible inner support tube. The elongate flexible inner support tube may be an inner coil-wound tube. In some examples the elongate flexible inner support tube is a laser-cut hypotube.

[0040] The compression layer may comprise a bladder configured to apply a positive pressure to compress the plurality of lengths of pressure-compression tendons against the elongate flexible inner support tube. The compression layer may be configured to apply a negative pressure to compress the plurality of lengths of pressure-compression tendons against the elongate flexible inner support tube. The lengths of pressure-compression tendons may be within a plurality of guides / tubes along the length that are open periodically (e.g., every x mm, where x is between about 0.5 mm and 5 mm or more, between about 0.5 mm and 4.5 mm or more, between about 0.5 mm and 5 mm or more, etc.) to expose the tendon.

[0041] The lengths of pressure-compression tendons may be blunted (e.g., capped) at their proximal ends. The lengths of pressure-compression tendons may be secured to the elongate flexible inner support tube by a sheath or a plurality of sheaths. In some cases, the sheath includes an inner channel within which the pressure-compression tendon may slide. The sheath may be compressed against the pressure-compression tendon, thus, the sheath may comprise a soft material, e.g., a material having a durometer of 60A or less on the Shore A scale. In some cases, even examples in which the pressure-compression tendons are within a sheath, the sheath may be open along the length (or may include a plurality of smaller sheaths, leaving openings by which the pressure-compression tendon may directly contact the compression layer. This may both make the device more flexible and may increase the rigidity of the device. In some examples the sheath comprises a braid. The plurality of lengths of pressure-compression tendons may comprise between 4 and 24 lengths of pressure- compression tendons.

[0042] Any of these devices may include an elongate flexible outer support tube extending in the proximal to distal length over the elongate flexible inner support tube, the plurality of lengths of pressure-compression tendons, and the compression layer.

[0043] Also described herein are methods of using these devices, including hybrid devices. For example, a method may include: steering a rigidizing device so that the rigidizing device bends while in a flexible configuration, wherein the rigidizing device comprises elongate flexible inner support tube extending in a proximal to distal length, a plurality of lengths of pressure-compression tendons that extend lengthwise along the - 10 - SG Docket No.: 13668-727.600elongate flexible inner support tube in a distal region of the rigidizing device, and a rigidizing layer extending over a proximal region of the rigidizing device, wherein the rigidizing layer comprises a plurality of filament lengths crossing over and under each other and configured shear relative to each other; and applying pressure to compress the rigidizing layer in the proximal region and the plurality of lengths of pressure-compression tendons in the distal region against the elongate flexible inner support to convert the rigidizing device to a rigid configuration; and releasing the pressure to convert the rigidizing device to the flexible configuration.

[0044] Steering the distal end region may comprise using one or more of the lengths of pressure-compression tendons to steer the distal end region. In some examples steering the distal end region comprises copying the shape of an elongate device within a lumen of the rigidizing device.

[0045] The elongate device within the lumen of the rigidizing device may comprise a rigidizing endoscope device. Any of these methods may include inserting the device into a lumen of a patient’s body.

[0046] Applying pressure may comprise applying a positive pressure to drive a compression layer of the rigidizing device against the rigidizing layer and against the plurality of lengths of pressure-compression tendons to lock the rigidizing device in the rigid configuration. In any of these apparatuses, the pressure-compression tendon that rigidizes may be present at an angle between the pressure-compression tendon and the long axis of the device (e.g., the long axis of the elongate tube) is either zero (e.g., parallel) or nearly zero. This is different than the angle between the plurality of strand lengths that cross over and under each other in the rigidizing layer that may be used with any of these devices including pressure-compression tendons. Although the small angle for the rigidizing layer, as well as the overlapping strands, may provide a high degree of rigidity, the pressure-compression tendons described herein may also be configured to provide a high degree of rigidity. The techniques described herein may contribute toward this high degree of rigidity, including the application of positive pressure and the arrangement of elements. In some cases, the use of pressure-compression tendons in the distal end and rigidizing layers in the more proximal regions may provide a balance between rigidity and flexibility, particularly at the distal end of the device. These apparatuses and methods may be particularly helpful in nested systems, e.g., using a pair of concentrically-arranged rigidizing devices.

[0047] As already mentioned above, applying pressure may comprise applying a negative pressure to drive a compression layer of the rigidizing device against the rigidizing layer and - 11 - SG Docket No.: 13668-727.600against the plurality of lengths of pressure-compression tendons to lock the rigidizing device in the rigid configuration.

[0048] Also described herein are nested systems including one or more of the apparatuses that include one or more regions rigidizable by pressure-compression tendons. For example, a system of nested rigidizing devices may include: a first rigidizing device comprising: an elongate flexible inner support tube extending in a proximal to distal length; a plurality of lengths of pressure-compression tendons extending lengthwise along the elongate flexible inner support tube; and a compression layer configured to compress the plurality of lengths of pressure-compression tendons against the elongate flexible inner support tube when pressure is applied, wherein the rigidizing device is configured to change between rigid and flexible states by the application of or release of the pressure; and a second rigidizing device configured to rigidize, the second rigidizing device nested with the first rigidizing device; wherein the first and second rigidizing devices are configured to translate relative to one another and to rigidize to propagate a shape along the nested system. The first and second rigidizing devices may be nested relative to each other. In some cases, the second rigidizing device may be nested within the first rigidizing device. In some cases, the first rigidizing device is nested within the second rigidizing device.

[0049] The plurality of lengths of pressure-compression tendons of the first rigidizing device may extend over a distal region of the elongate flexible inner support tube, and may further comprise a proximal region comprising a rigidizing layer extending over the elongate flexible inner support tube within the proximal region, the rigidizing layer comprising a plurality of filament lengths crossing over and under each other and configured shear relative to each other in the flexible state, further wherein the compression layer configured to compress the rigidizing layer against the elongate flexible inner support tube when pressure is applied to rigidize the proximal region.

[0050] At least some of the lengths of pressure-compression tendons may extend proximally to a proximal end of the rigidizing device and are configured for steering the distal end of the elongate flexible inner support tube. At least some of the lengths of pressure- compression tendons may either be unattached at their proximal end or may form a loop connecting two of the length of pressure-compression tendons.

[0051] In any of the apparatuses described herein, the apparatus may include steering tendons. The steering tendons may be part of the pressure-compression tendons or may be separate from the pressure-compression tendons. In any of these apparatuses the steering cables may be configured to steer (e.g., bend) just the distal end region of the apparatus. For - 12 - SG Docket No.: 13668-727.600example, the apparatus may include links within the elongate body that may be bent by driving the steering tendons (e.g., pushing / pulling).

[0052] For example, the plurality of lengths of pressure-compression tendons may comprise a steering sub-set of tendons extend proximally to a proximal end of the rigidizing device and are configured for steering the distal end of the elongate flexible inner support tube, and further wherein the plurality of lengths of pressure-compression tendons comprises a non-steering subset of tendons that are either unattached at their proximal end or that form a loop connecting two of the length of pressure-compression tendons.

[0053] Any of these systems may include a set of steering tendons extending along the proximal to distal length. The lengths of pressure-compression tendons may be radially spaced apart from each other along the proximal to distal length of the elongate flexible inner support tube. The elongate flexible inner support tube may be an inner coil-wound tube, a laser-cut hypotube, etc. The compression layer may comprise a bladder configured to apply a positive pressure to compress the plurality of lengths of pressure-compression tendons against the elongate flexible inner support tube. In some examples the compression layer is configured to apply a negative pressure to compress the plurality of lengths of pressure- compression tendons against the elongate flexible inner support tube. The lengths of pressure-compression tendons may be within a plurality of guides / tubes along the length that are open periodically to expose the tendon.

[0054] All of the methods and apparatuses described herein, in any combination, are herein contemplated and can be used to achieve the benefits as described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] A better understanding of the features and advantages of the methods and apparatuses described herein will be obtained by reference to the following detailed description that sets forth illustrative embodiments, and the accompanying drawings of which:

[0056] FIGS.1A and 1B illustrate an example of a portion of an elongate rigidizable device that may be rigidized by the application of negative pressure including pressure- compression tendons extending lengthwise along an elongate flexible inner support tube. FIG.1A shows the device in a flexible configuration. FIG.1B shows the device is a rigidized configuration.

[0057] FIGS.2A and 2B illustrate an example of a portion of an elongate rigidizable device that may be rigidized by the application of positive pressure including pressure- compression tendons extending lengthwise along an elongate flexible inner support tube. - 13 - SG Docket No.: 13668-727.600FIG.2A shows the device in a flexible configuration. FIG.2B shows the device is a rigidized configuration.

[0058] FIGS.3A-3C illustrate an example of a section through one example of an elongate rigidizable device including pressure-compression tendons and articulating extending lengthwise along the device. FIGS.3B and 3C show magnified views of sections 3B and 3C from FIG.3A.

[0059] FIGS.4A-4C illustrate one example of a rigidizing device including pressure- compression tendons extending lengthwise along the distal end region of the device. FIG.4A shows a top view of the device fully assembled and in the flexible configuration. FIG.4B shows an example of a top view of a portion of the device with the outer covering, including the compression layer, removed. FIG.4C shows an example of the device in the rigidized configuration, holding a set shape.

[0060] FIG.4D illustrates an example of a pair of nested rigidizing devices including at least one rigidizing device that includes pressure-compression tendons as described herein.

[0061] FIG.5 schematically illustrates one example of a method of using a rigidizing device including pressure-compression tendons as described herein.

[0062] FIGS.6A-6F illustrate examples of rigidizing devices including a distal region that includes pressure-compression tendons extending lengthwise along the distal end region and proximal region that includes a rigidizing layer formed of a plurality of filament lengths crossing over and under each other. In FIG.6A the apparatus includes a plurality of pressure- compression tendons extending lengthwise configured to both steer and rigidize the distal region. The apparatus shown in FIG.6B includes a plurality of pressure-compression tendons extending lengthwise down the proximal region that are configured to assist in rigidizing but are not coupled at the proximal region for actively steering the distal region. FIG.6C shows an example of a rigidizing device including a first subset of pressure-compression tendons extending lengthwise that are configured for steering and a second subset of pressure- compression tendons extending lengthwise that are configured for rigidizing but not steering. FIG.6D shows an apparatus including a plurality of pressure-compression tendons extending lengthwise down the proximal region that are configured to assist in rigidizing but are not coupled at the proximal region for actively steering the distal region. In FIG.6E all or some of the pressure-compression tendons extend from the distal end region and overlap with the rigidizing layer (formed of a plurality of lengths of filaments) in the proximal region. In FIG. 6F the pressure-compression tendons extend from the distal end region and overlap completely with the rigidizing layer, as shown. - 14 - SG Docket No.: 13668-727.600

[0063] FIGS.7A-7B illustrate an example of a section through a first region of a proximal region that includes a rigidizing layer formed of a plurality of filament lengths crossing over and under each other that may form part of an apparatus such as that shown in any of FIGS.6A-6C. FIG.7A shows a radial cross-section, while FIG.7B shows a section through a region of the radial cross-section shown in FIG.7A.

[0064] FIGS.8A-8B illustrate an example of a section through a first region of a proximal region that includes a rigidizing layer formed of a plurality of filament lengths crossing over and under each other that may form part of an apparatus such as that shown in any of FIGS.6A-6C. FIG.8A shows a radial cross-section, while FIG.8B shows a partial longitudinal section.

[0065] FIG.9 schematically illustrates one example of a method of using a rigidizing device including both pressure-compression tendons and a rigidizing layer formed of a plurality of lengths of filaments crossing over each other.

[0066] FIGS.10A-10H illustrate an example of a method of operating a nested pair of rigidizing elongate devices that may selectively rigidize and un-rigidize to propagate a shape through a tortious pathway.

[0067] FIG.11 illustrates an example of a robotic system including a rigidizing device including pressure-compression tendons extending lengthwise.

[0068] FIGS.12A-12G illustrate examples of pressure-compression tendons that may be used with any of the apparatuses described. In FIG.12A the pressure-compression tendons are linear lengths that are arranged in parallel (or approximately in parallel). FIG.12B shows an example of pressure-compression tendon lengths that are formed of a single tendon that is zig-zagged (with an offset) laterally. FIG.12C is another example of a plurality of pressure- compression tendon lengths that are formed from a single tendon that is formed into a square wave pattern, as shown. FIG.12D shows an example of a plurality of pressure-compression tendon lengths that is / are enclosed in discrete tubes (these lengths may be part of the same tendon that doubles back, or it may be separate tendons). In FIG.12E the pressure- compression tendons are formed of a single tendon that has a sinusoidal pattern (e.g., having rounded or curved ends). In FIG.12F the pressure-compression tendons are formed of discrete U-shaped lengths of tendon. In FIG.12G the pressure-compression tendons are discrete lengths of U-shaped lengths of tendon that double back onto each other.

[0069] FIG.12H shows an example of a rigidizing device including the plurality of pressure-compression tendons at the distal end.

[0070] FIG.12I shows the device of FIG.12H steered into a curved configuration. - 15 - SG Docket No.: 13668-727.600

[0071] FIGS.13A-13B illustrate examples of pressure-compression tendons arranged at a distal end region of a rigidizing device. FIG.13A shows a single length of pressure- compression tendon. FIG.13B shows a rigidizing device having a plurality of the pressure- compression tendons similar to that shown in FIG.13A arranged along the distal end region in non-overlapping regions.

[0072] FIGS.14A-14B illustrate examples of pressure-compression tendons arranged at a distal end region of a rigidizing device. FIG.14A shows a pressure-compression tendon forms a pair of tendon lengths that are continuous, shaped as a loop. FIG.14B shows a rigidizing device having a plurality of the pressure-compression tendons similar to that shown in FIG.13A arranged along the distal end region in overlapping regions.

[0073] FIGS.15A-15E illustrate examples of sections through a portion of a rigidizing device including pressure-compression tendons, as described herein. FIG.15A shows a pressure-actuated rigidizing device including a pressure-compression tendon adjacent to a rigidizing layer in which the rigidizing layer and tendon are compressed against the outer layer (e.g., an outer reinforced tube). FIG.15B shows a pressure rigidizing device similar to that shown in FIG.15A, but with the rigidizing layer and tendon compressed against the inner layer (e.g., an inner reinforced, e.g., coil-wound, tube). FIG.15C shows an example of a device in which the pressure-compression tendon is compressed against the outer layer and does not include an additional rigidizing layer. FIG.15D is an example of a device in which the pressure-compression tendon passes through a rigidizing layer. FIG.15E shows an example in which a pair of pressure-compression tendons are compressed against both the inner and outer tubes.

[0074] FIGS.16-16F illustrate one example of a method of assembling a set of pressure- compression tendons for a rigidizing device as described herein.

[0075] FIGS.17A-17B illustrate an example of a set of pressure-compression tendons formed of a single wire (or cable) that is formed into a longitudinally-arranged configuration connected at either ends and incorporated into a distal end region of a rigidizing apparatus. FIG.17B shows an enlarged view of the example shown in FIG.17A.

[0076] FIGS.18A-18B show an example of a distal end region of a rigidizing device having a set of free-floating distal pressure-compression tendons that are integrated the plurality of lengths of the rigidizing layer (e.g., knit, braid, weave, mesh, etc.). In FIGS.18A- 18B, some of the ends of the pressure-compression tendons are obscured by other layers.

[0077] FIGS.19A-19B illustrate one example of an apparatus including a plurality of pockets formed within the support layer (e.g., the outer coil-wound tube layer) of the rigidizing device to hold and allow compression of pressure-compression tendons. The - 16 - SG Docket No.: 13668-727.600pockets serve to both allow for movement, but also to restrict that movement within a prescribed zone (i.e. the pocket). In FIG.19A the outer support layer, e.g., outer coil-wound tube layer, is shown partially transparent.

[0078] FIGS.20A-20B schematically illustrate another example of a rigidizing device including longitudinally-arranged pockets or channels for distal pressure-compression tendons that are within the layers of the device, such as within the outer or inner support layer (e.g., coil-wound support layer, such as the outer or inner coil wound tube). FIG.20A shows a transparent view of a portion of rigidizing device, including pockets through which the pressure-compression tendons maybe fed. FIG.20B shows section through the portion shown in FIG.20A.

[0079] FIGS.21A-21B illustrate an example of a rigidizing device including longitudinally-arranged pockets for passing one or more pressure-compression tendons in which the outer support layer is made partially transparent to show the pockets. FIG.21B shows an enlarged view of the distal end region of the rigidizing apparatus shown in FIG. 21A.

[0080] FIGS.22A-22B illustrate one example of a pair of lengths of pressure- compression tendon, formed of a single mono- or multifilament, which may be configured at one or both ends as a torsion spring. DETAILED DESCRIPTION

[0081] It is particularly challenging to rigidize the distal end region of a rigidizing apparatus that transitions between a flexible state and a rigid state, particularly in devices that are highly flexible in the flexible state and that transition into a rigid state (or states) that is one or more orders of magnitude stiffer. Pressure-rigidizing apparatuses in particular may benefit from the use of a rigidizing layer that comprises a plurality of lengths of rigidizing filaments that cross over each and slide relative to each other in the more flexible states, but that are compressed and locked against each other in the rigid states. Distal end regions may require both enhanced flexibility and enhanced stiffness. The distal end regions of such devices may require enhanced stiffness as compared to more proximal regions, because the distal end may see a higher load than more proximal regions. The distal end regions of such devices may require enhanced flexibility as compared to more proximal regions, because the distal end may need to flex or bend more, with a lower applied force.

[0082] In general, described herein are rigidizing apparatuses, e.g., device and system, including but not limited to endoscopes, catheters, overtubes, guidewires, etc., that may include pressure-compression tendons in the distal end region that may enhance the rigidity - 17 - SG Docket No.: 13668-727.600of the distal end region preferentially. In particular, described herein are methods and apparatuses in which a flexible distal end region of the rigidizing apparatus is rigidized using a plurality of pressure-compression tendons that extend longitudinally down the length of the distal end region; more proximal regions of the rigidizing apparatus may be rigidized using a second pressure-rigidizing layer, such as a plurality of lengths of filaments that cross over each. These apparatuses and methods may therefore maintain high flexibility of the entire rigidizing apparatus including in particular the distal end region, while rigidizing to a highly rigid configuration including at the distal end region. In some cases, while the entire (proximal and distal) regions of the rigidizing apparatus may transition between highly flexible and highly rigid states, the apparatuses described herein including pressure- compression tendons may have a distal end region that delivers enhanced rigidity as compared to the more proximal region(s) using the same pressure actuation.

[0083] In some cases, all, or a majority of the length of the rigidizing apparatus may be rigidized by a plurality of pressure-compression tendons. In any of these apparatuses, the proximal end region(s) may be rigidized, at least in part, using a different rigidizing layer, such as a plurality of length of filament that cross over each other and may slide relative to each other in the flexible state(s). Alternatively, just the distal end region may be rigidized by pressure-compression tendons, and the proximal end may be rigidized by the second pressure rigidizing layer. These two zones can have a gap between them. These two zones can abut. These two zones can have an overlap region - in some cases an overlap region may be present between the distal end region (including the pressure-compression tendons) and the proximal region (including the second pressure rigidizing layer).

[0084] In some examples, the distal end region may be steerable. In some cases, the pressure-compression tendons may be configured as, or may include, steering tendons. Alternatively, in any of these apparatuses the distal end of the rigidizing apparatus is not actively steered.

[0085] Pressure-rigidizing apparatuses may dynamically convert between a rigid configuration and a flexible configuration by the application of pressure, including either or both positive and negative pressure (e.g., vacuum). The methods and apparatuses described herein may be particularly useful in increasing the flexibility of at least the distal region of these apparatuses without significantly increasing the thickness of the apparatus, and without significantly reducing the overall stiffness that may be achieved by the apparatus, including the distal end, in the rigid configuration. The methods and apparatuses described herein may be particularly useful in increasing the stiffness of at least the distal region of these apparatuses without significantly increasing the thickness of the apparatus, and without - 18 - SG Docket No.: 13668-727.600adversely affecting the flexibility that may be achieved by the apparatus, including the distal end region, in the flexible configuration. In general, these apparatuses and methods may include a plurality of pressure-compression tendons (or lengths of tendons) that extend lengthwise along the apparatus, such as along an elongate flexible inner and / or outer support tube, and in particular along the distal end. The pressure-compression tendons may be configured to driven against another portion of the apparatus, such as an elongate flexible inner and / or outer support tube or some other intermediate portion of the apparatus, by the application of pressure (positive or negative pressure) to secure the tendons in place. Pressure may be positive pressure or negative pressure (or in some cases a combination of positive and negative pressure). Pressure may be applied by a bladder layer. The pressure-compression tendons may be compressed along all or a portion of their length (e.g., the proximal end region), either continuously or in an intermittent manner along the length of the pressure- compression tendon. In some cases, the pressure-compression tendons may also be configured to allow steering of the distal region when the apparatus is in the flexible (“de- rigidized” state). In any of these examples, the same source of pressure may be used to rigidize the pressure-compression tendons as the second rigidizing layer.

[0086] The apparatuses and methods described herein may therefore provide a size- efficient mechanism that utilizes a single layer of tendons for rigidizing and, in some cases, also for articulation. In some cases, the tendons, referred to herein as pressure-compression tendons, may be used with a rigidizing layer (e.g., a “second rigidizing layer”), which may be a mesh, knit, braid, woven, etc. set of lengths of filaments that are also configured to rigidize by the application of pressure. In some cases, the distal end region is rigidizing by the pressure-compression tendons, while the more proximal region is rigidized by a rigidizing layer. In some case the two regions may overlap, e.g., the pressure-compression tendons may be embedded within the rigidizing layer.

[0087] The apparatuses described herein may provide an elegant mechanical solution that does not necessitate independent control of multiple segments of the articulation section or shape sensing / tip position control feedback. In addition, these methods and apparatuses do not require clamp engagers or other localized locking mechanisms, as the tendons may be directly compressed by the compression layer. The use of pressure-compression tendons, which may not cross over each other, and may be generally oriented longitudinally, effectively having a very low (or zero) braid angle, as compared with rigidizing layer comprising a plurality of strand lengths that cross over and under each other, may provide high flexibility, particularly in the distal regions of the apparatus. In some examples the use of a rigidizing layer, which may be highly effective at rigidizing, may be distorted in regions - 19 - SG Docket No.: 13668-727.600where the articulation exceeds 90 degrees or more (e.g., between 90-180 degrees) at smaller radius of curvatures. The pressure-compression tendons described herein may freely slide longitudinally, either within a structure (e.g., sheath, channel, tube, etc.) in the unconstrained (flexible) configuration, but may be constrained along their length in the rigid configuration. In general, the pressure-compression tendons may be configured so that they do not poke or get caught in the structure of the device.

[0088] Thus, the apparatuses described herein are configured to allow the articulation of tight bend radii and rigidizing without any permanent change to the flexural properties of the apparatus, which may not be achieved with a rigidizing layer alone. These apparatuses may hold a shape (e.g., curve) deterministically, i.e., hold both articulation angle and shape simultaneously. These apparatuses may also beneficially provide a pressure-dependent magnitude of the stiffness achieved; for example, if positive pressure is applied to rigidize the apparatus, stiffness achieved may increase with the magnitude of the pressure applied. This is possible because the applied pressure may drive the compression layer against the length of the pressure-receiving tendons, locking the tendons along their entire length, rather than, e.g., just at the proximal end region. Unlike other mechanisms for locking a steering or articulation tendon in place that may use a drive motors / articulation lever to hold the articulation mechanism at a specific angle (and which may allow the proximal bend radius to become larger and the distal smaller while maintaining the same articulation angle, allowing drift of the tip position under loads), the methods and apparatuses described herein are configured to lock the position of the tendon(s) along all or much of the length of the tendon(s) in the rigid configuration. This configuration may allow the apparatus to hold the specific shape without losing the curve / bend, or allowing significant drifting of the tip position. The pressure-compression tendons described herein may also be configured to prevent or limit buckling and distortion, even when bent to a tight bend radius (e.g., in its free condition). Thus, the methods and apparatuses described herein may also provide an improved control of the articulation of the apparatus, and in some cases may be used without drive motors, or with a reduced number of drive motors.

[0089] The pressure-compression tendons may be formed as monofilaments or a plurality of filaments, such as a cable. A pressure-compression tendon may be formed of any appropriate material, such as, but not limited to polymeric materials (e.g., inelastic polymeric materials such as polycarbonate, polymethyl methacrylate (PMMA), polyethylene, etc.), metallic materials (e.g., metal alloys), or some combination thereof. In some cases, the pressure-compression tendons may be a metallic or polymeric material. For example, the pressure-compression tendons may be formed of a stainless steel, nickel titanium (e.g., - 20 - SG Docket No.: 13668-727.600NITINOL) or other material. The pressure-compression tendons may be any appropriate diameter, such as between about 0.001 inch OD and 0.020 inch OD (e.g., about 0.009 in, 0.002 inch, 0.003 inch, 0.004 inch, 0.005 inch, 0.006 inch, 0.007 inch, 0.008 inch, 0.09 inch, 0.010 inch, 0.011 inch, 0.012 inch, 0.013 inch, 0.014 inch, 0.015 inch, 0.016 inch, 0.017 inch, 0.018 inch, 0.019 inch, 0.020 inch, 0.025 inch, 0.030 inch, etc.) OD stainless wires. The pressure-compression tendons may be coated. In some cases, the pressure-compression tenons may be coated with a material to increase the grip strength of the pressure- compression tenon under compression, while allowing or enhancing sliding. For example, the pressure-compression tenon may be coated with a polymeric material (such as Pebax), or the like. In some cases, the pressure-compression tenons may be coated with a relatively lubricious material, or may be held in a lubricous sleeve, jacket, sheath, etc. (such as an ePTFE / Teflon material). As mentioned, the pressure-compression tenons may be cables or fibers; the pressure-compression tenon may be monofilaments or bundles of filaments.

[0090] Any of the methods and apparatuses described herein may be used with shape sensing, e.g., to detect or determine the shape of the apparatus in the flexible and / or rigid configuration. Any of these methods and apparatuses may also be used with one or more closed-loop control algorithms. For example, one or more shape sensors (e.g., an EM sensor or shape sensing light fiber, etc.) may be used as input to a control algorithm to sense tip position and / or orientation. When a force is applied to the tip the control algorithm can use a mixture of tendon tension control (adjustment of the axial length of the articulation section) and articulation to try and maintain the tip at its desired position.

[0091] The rigidizing apparatuses and methods described herein may be part of a medical access system for diagnosing and treating regions of the body that are otherwise hard to access and operate within, particularly during minimally or non-invasive procedures. In particular, these methods and apparatuses may be used in highly tortuous and / or unsupported regions of the body. These methods and apparatuses may be used in combination with, and / or may modify and improve the rigidizing (e.g., rigidizable) devices and methods of using them described in U.S. Patent No.11,135,398, (titled “DYNAMICALLY RIGIDIZING COMPOSITE MEDICAL STRUCTURES”), (U.S. Patent Application No.17 / 604,203, also titled “DYNAMICALLY RIGIDIZING COMPOSITE MEDICAL STRUCTURES”), International Patent Application No. PCT / US2021 / 024582 (titled “LAYERED WALLS FOR RIGIDIZING DEVICES”), International Patent Application No. PCT / US2021 / 034292 (titled “RIGIDIZING DEVICES”), International Patent Application No. PCT / US2022 / 014497, (titled “DEVICES AND METHODS TO PREVENT INADVERTENT MOTION OF DYNAMICALLY RIGIDIZING DEVICES”), International Patent Application No. - 21 - SG Docket No.: 13668-727.600PCT / US2022 / 019711 (titled “CONTROL OF ROBOTIC DYNAMICALLY RIGIDIZING COMPOSITE MEDICAL STRUCTURES”), U.S. Provisional Patent Application 63 / 265,934 (titled “METHODS AND APPARATUSES FOR REDUCING CURVATURE OF A COLON”), U.S. Provisional Patent Application 63 / 296,478 (titled “RECONFIGURABLE STRUCTURES”), U.S. Provisional Patent Application 63 / 308,044, (titled “DYNAMICALLY RIGIDIZING COMPOSITE MEDICAL STRUCTURES”), U.S. Provisional Patent Application 63 / 324,011 (titled “METHODS AND APPARATUSES FOR NAVIGATING USING A PAIR OF RIGIDIZING DEVICES”), U.S. Provisional Patent Application No.63 / 342,618 (titled “EXTERNAL WORKING CHANNELS FOR ENDOSCOPIC DEVICES”), U.S. Provisional Patent Application 63 / 335,720 (titled “HYGIENIC DRAPING FOR ROBOTIC ENDOSCOPY”) and U.S. Provisional Patent Application No.63 / 332,686 (titled “MANAGING AND MANIPULATING A LONG LENGTH ROBOTIC ENDOSCOPE”), each of which is herein incorporated by reference in its entirety. Alternatively, the apparatuses and methods described herein may be used as (or as part of) a non-medical system.

[0092] Rigidizing apparatuses as described herein may be configured to rigidize when negative pressure and / or positive pressure is applied. These rigidizing apparatuses as described herein may be used in conjunction with other rigidizing devices that rigidize with other methods, including those that do not rely upon the application of positive or negative pressure. For example, a rigidizing device may be configured to include multiple layers arranged into an elongate catheter-like body. The device may include a handle or other manipulator and may include a connection to one or more pressure sources. Applying pressure from the pressure source may be controlled by multiple methods, including operation of a handle or an electronically controlled device. Control may result in a pressure differential that causes the device to transition between a highly flexible configuration, allowing the tubular body to readily bend, when steered or otherwise guided (e.g., over a guidewire, etc.), and one or more (e.g., a continuum) of rigid configurations. In some examples, particularly (but not exclusively) in reference to apparatuses that rigidize based on the application of positive pressure, the rigidity of the elongate body is proportional to the applied pressure differential, so that the greater the pressure differential, the more rigid the device may become over at least a range of pressure differential values.

[0093] Any of the apparatuses described herein may include either pressure-compression tendons extending lengthwise along the device to rigidizing the length of the device or both pressure-compression tendons and a rigidizing layer (comprising a plurality of filament lengths crossing over and under each other and configured shear relative to each other in the - 22 - SG Docket No.: 13668-727.600flexible state) to rigidize all or a portion of the apparatus. In particular, it may be particularly beneficial to provide apparatuses that include a distal region, in some cases at or near the distal end, that are rigidized by the use of a plurality of pressure-compression tendons and a proximal region (which may overlap with or be non-overlapping with) that is rigidized by the use of a rigidizing layer formed of a plurality of filament lengths crossing over and under each other and configured shear relative to each other in the flexible state.

[0094] In general, these apparatuses may include multiple layers, including a plurality of lengths of pressure-compression tendons that is positioned between (or in some cases embedded within), e.g., a support layer and a compression layer. A compression layer may engage with the plurality of lengths of pressure-compression tendons (and optionally in some cases a rigidizing layer). In some examples the apparatus may include a combined compression layer in which the plurality of lengths of pressure-compression tendons are embedded or encapsulated. Described herein are pressure-compression tendons that may be particularly well suited to rapid and precise actuation over a variety of pressures, including in particular positive pressures (e.g., high positive pressures, i.e., atm of about 2 or more, 4 or more, 6 or more, 8 or more, 10 or more, 15 or more, 20 or more, 30 or more, etc.). Any of these apparatuses may also be configured so that at least some of the inner and / or outer layers making up the rigidizing (e.g., rigidizable) device have different durometers on the inner and outer portion of either the inner or outer layers. Also described herein are apparatuses and methods including nested sets of rigidizing apparatuses, which may include any of these rigidizing devices.

[0095] In general, an apparatus as described herein may include an elongate flexible inner support tube that extends along a proximal to distal length, which may extend the full (or nearly full) length of the apparats. The elongate flexible inner support tube may be configured to prevent collapse of the tube. In some cases, the inner support tube is reinforced with one or more supports (e.g., coil-wound tube supports, braid, etc.). For example, the inner support tube may include one or more helically-wound filaments (wires, bands, etc.) or ring shapes, that are embedded within a low-durometer material (e.g., reflow material). In some cases, the inner support tube comprises a laser-cut hypotube. In general, the inner support tube is configured to prevent collapse under the full range of forces, e.g. pressure force, applied on the apparatus. The inner support tube may have an inner lumen that is open at the distal and proximal ends and the inner support tube may be configured to prevent a change in the inner diameter of the inner support tube even as force (e.g., collapse or constriction force) is applied against the inner support tube. - 23 - SG Docket No.: 13668-727.600

[0096] Any of these apparatuses may include one more pressure-compression tendons. These pressure-compression tendons may comprise a plurality of lengths of pressure- compression tendons and may generally extend lengthwise along the elongate flexible inner support tube, either directly or indirectly (e.g., separated from the flexible inner support tube by an intermediate layer, such as a slip layer, compression layer, etc. The pressure- compression tendons may be formed of a metallic and / or polymeric material, and may be a single filament or a plurality of filaments. The pressure-compression tendons may be a cable. The pressure-compression tendons may be formed of a relatively inelastic material, and may be formed into a relatively inelastic tendon. In some cases, a plurality (e.g., two or more) of pressure-compression tendons may be formed of a single long strand of material that doubles back over itself (e.g., forming a U-shape or a ‘V-shape at one end) to form multiple lengths of pressure-compression tendons.

[0097] The apparatuses described herein may include one or more compression layers configured to compress the plurality of lengths of pressure-compression tendons against the elongate flexible inner support tube when pressure is applied. In general, the compression layers descried herein may include one or more structural layers that may be (but are not limited to) a bladder layer(s) and / or sheets of materials that apply a compressive force on or against the rigidizing layer to rigidize the rigidizing layer in response to the application of pressure (e.g., fluid pressure, such as air pressure, saline pressure, etc.). In examples having both pressure-compression tendons and a rigidizing layer, in some examples both the pressure-compression tendons and the rigidizing layer may be rigidized by the same compression layer. Alternatively, in some examples the apparatus may include more than one compression layer. For example, the pressure-compression tendons may be rigidized by a first compression layer and the rigidizing layer may be rigidized by a second compression layer. If multiple compression layers are used the compression layer may be actuated by the same pressure source (e.g., actuated together). Alternatively in some examples, different regions of the apparatus may be separately actuated by the use of different compression layers, allowing selective rigidization along the length of the apparatus.

[0098] In general, the rigidizing devices described herein are generally configured to change between rigid and flexible states by the application of or release of the pressure. Any appropriate pressure-transmitting medium may be used to apply pressure to drive the compression layer against the pressure-compression tendons and / or rigidizing layer. For example, the pressure-transmitting medium may include liquid (e.g., saline, oil, etc.), gas (e.g., air, nitrogen, CO2, etc.). The pressure-transmitting medium may be applied into one or - 24 - SG Docket No.: 13668-727.600gaps (e.g., pressure gaps) and may be removed actively (e.g., via pumping, suction, etc.) or passively (e.g., via venting, etc.).

[0099] The apparatuses described herein may generally include one or more fluid lines for delivery of the pressure-transmitting medium into the apparatus to control the rigidization. For example, any of these methods an apparatus may include an inlet, e.g., at a proximal end region of the rigidizing device, that is configured to apply, or allow the application of, pressure into the apparatus, e.g., into a pressure gap, to compress the compression layer against the plurality of lengths of the pressure-compression tendons.

[0100] For example, FIG.1A illustrates an example of a portion of a rigidizing apparatus (e.g., a distal end region) that includes a plurality of pressure-compression tendons that may be used to rigidize the apparatus. In FIG.1A the apparatus is shown in the flexible configuration, with a plurality of lengths of pressure-compression tendons 121, 121’, 121’’ shown (in partially transparent view through the length of the body of the apparatus). FIG. 1A shows a section and partially-transparent longitudinal view, illustrating the arrangement of the pressure-compression tendons relative to other layers forming the apparatus. Three pressure-compression tendons are shown. As mentioned above, any appropriate number of tendons may be used. For example, four or more pressure-compression tendons (one in each quadrant), five or more pressure-compression tendons, six or more pressure-compression tendons, seven or more pressure-compression tendons, eight or more pressure-compression tendons, nine or more pressure-compression tendons, ten or more pressure-compression tendons, etc.

[0101] As shown in FIG.1A, the pressure-compression tendons extend lengthwise along the inner support tube 115. The pressure-compression tendons may extend in direction that is parallel to each other and to the length of the inner support tube. Thus, the pressure- compression tendons may be held or secured within the pressure-compression tendons so that their radial positions (e.g., in the parallel arrangement shown) are relatively fixed. In some cases, the pressure-compression tendons are held within one or more guides, e.g., loops, tubes, channels, etc. to maintain the radial position of the pressure-compression tendons. Such guides may be configured so that most of the length of the pressure-compression tendons (e.g., 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 80% or more 85% or more, 90% or more, 95% or more, etc.) are exposed so that the compression layer may compress them with the application of pressure to prevent the pressure-compression tendons from sliding when compressed. In the flexible configuration the apparatus may be configured so that the pressure-compression tendons are free to slide relative to the inner support tube. For example, the guides may include lubricated or low- - 25 - SG Docket No.: 13668-727.600friction surfaces (coatings, etc.) to allow the pressure-compression tendon to move longitudinally relatively unconstrained unless and until pressure is applied to drive the compression layer against the pressure-compression tendon(s).

[0102] In FIG.1A the apparatus 100 includes an inner lumen 120 extending along the proximal to distal length through the apparatus, e.g., through the inner support tube 115. The inner support tube and the inner lumen of the apparatus may be sized to allow passage of one or more tools (e.g., guidewires, manipulators, catheters, endoscopes, etc.).

[0103] The apparatus 100 shown in FIGS.1A and 1B also includes compression layer 123. The compression layer is generally configured to apply pressure against the plurality of pressure-compression tendons in order to convert the device between the rigid and flexible states. In FIG.1A the pressure-compression tendons are within the gap 111 and the compression layer 123 is formed as an outer layer that may be collapsed by applying negative pressure, e.g., vacuum, within the gap 111. This is shown in FIG.1B, in which the compression layer 123 is collapsed down onto the pressure-compression tendons 121, 121’, 121’’, preventing them from moving relative to the inner support tube 115.

[0104] The compression layer may be any appropriate layer for applying force against the pressure-compression tendons (and in some cases a rigidizing layer) to rigidize apparatus. In some examples the compression layer is a bladder. The compression layer may have a single sheet or may have multiple sheets (e.g., the compression layer may be inverted back over itself). In double-layer compression layers (e.g., inverted bladder layers), in which the compression layer is inverted over itself, the inner region between the two walls of the inverted bladder may be pressurized. The compression layer may be configured to conform against the pressure-compression tendons and / or rigidizing layer, as shown in FIG.1B. In this example the compression layer wraps around the pressure-compression tendons, preventing them from sliding. The compression layer may be configured to be relatively soft, and deformable (e.g., elastically deformable). In some cases, the compression layer may be configured to have a durometer of less than about 90 ShoreA (e.g., 80 ShoreA or less, 70 ShoreA or less, 60 ShoreA or less, 50 ShoreA or less, 40 ShoreA or less, 30 ShoreA or less, etc.). Alternatively, the compression layer may be configured so as not to conform to the pressure-compression tendons and / or compression layer, but to apply force against the pressure-compression tendons and / or compression layer. For example, the compression layer may be created so that it pushes but does not appreciably deform into the rigidizing layer. In some examples the compression layer comprises an elastomeric (e.g., stretchy) material. In some cases, the compression layer is not elastomeric. Thus, in some cases it may be surprisingly beneficial if the bladder layer is formed of an inelastic material that is - 26 - SG Docket No.: 13668-727.600flexible / compliant, but does not stretch significantly during use. The compression layer may be configured so that it pushes against and then deforms or distends around the tendons of the pressure-compression tendons and / or into or around the filaments of the rigidizing layer. For example, the compression layer may be plastic. The compression layer may be a plastomer. The compression layer may be a composite structure. For example, the compression layer may be formed of a less-stretchy material that may be an oversized material (e.g., polyethylene terephthalate (PET), nylon, low density polyethylene (LDPE), or a plastomer). Any of these apparatuses may include multiple different rigidizing regions, e.g., along the length of the apparatus, which may be separately or collectively actuated.

[0105] The compression layer may be formed by multiple methods. In some examples the compression layer comprises a bladder that is extruded as a tube. In some examples the compression layer is formed from a sheet that is created (e.g., extruded, solution cast, blown, etc.) and then heat-sealed or bonded into a tubular structure. Tubes can be created by dipping, e.g., over a mandrel into an elastomer bath or a solvated elastomer bath. A layer may be created by blowing a film. In this case, the film starts out as a bubble of material (typically a plastic or a plastomer, but sometimes also an elastomer) that, with high pressure air behind it, expands or stretches into a tube that is then carried (usually vertically) as it cools while it is diametrically constrained. This approach provides leak-proof quality control and may create a structure that is lower cost and thinner. In some cases, as shown in FIGS.3A-3C, discussed below, the compression layer is formed over the pressure-compression tendons and surrounds the pressure-compression tendons.

[0106] In FIG.1B, the device 100 of FIG.1A is shown with the pressure-compression tendons in a locked configuration, in which the compression layer is collapsed down onto the pressure-compression tendons and the inner support tube by the application of negative pressure within the gap 111 region. The gap region may be sealed.

[0107] In FIGS.1A-1B the compression layer forms the outer layer of the rigidizing device 100. One or more additional layers may be included radially inward to the compression layer and / or pressure-compression tendons and / or inner support tube. For example, a slip layer may be included to reduce friction between the pressure-compression tendons and the compression layer and / or inner support tube unless and until the compression layer applies force against the pressure-compression tendons by the application of pressure. One or more additional layers may be included radially outward of the compression layer, including an outer support tube and / or an outer layer. The outer layer may provide a sterile or sterilizable barrier, and / or may be lubricious, to assist in inserting / removing the apparatus from the body. - 27 - SG Docket No.: 13668-727.600

[0108] Although the example of the apparatus shown in FIGS.1A-1B may be actuated by the application of negative pressure, any of these apparatuses may be actuated, e.g., converted from a flexible configuration to a rigid configuration, by the application of positive pressure. For example, FIGS.2A-2B schematically illustrate an example of a portion of a rigidizing device 200 that includes a plurality of lengths of pressure-compression tendons 221 extending lengthwise along the elongate flexible inner support tube 215. The pressure-compression tendons 221 are within a gap 211 (e.g., a pressure gap) and a compression layer 223 is radially outward from the pressure-compression tendons 221. In this example eight pressure- compression tendons are shown. An outer support tube 201, which may be similar to the inner support tube 215, is radially outward of the compression layer 223, the pressure- compression tendons and the inner support tube. In the example shown in FIGS.2A-2B the compression layer is configured as a bladder (e.g., the compression layer is formed by the side of the bladder facing the pressure-compression tendons). The device 200 also includes a gap 211 into which the compression layer may expand when positive pressure is applied into the bladder (inside of bladder 224). The outer support tube limits the bladder layer from expanding radially outward and drives the compression layer 223 (e.g. bladder) against the pressure-compression tendons and the inner support tube 215, rigidizing the device by preventing the pressure-compression tendons from sliding or moving relative to the inner support tube. This is illustrated in FIG.2A. In FIG.2B the bladder 223’ is shown expanded 224’ and is driven against the pressure-compression tendons 221 and the inner support tube 215.

[0109] In general, in any of the apparatuses described herein, the use of pressure- compression tendons that extend along the length (e.g., parallel with the long axis) of the inner support tube and the lumen 220 of the elongate rigidizing device may be particularly beneficial where the thickness of the device, e.g., at the flexible and / or steerable distal region of the device, may be limited. In any of these apparatuses the thickness of the distal end region may be kept low, e.g., by limiting the number of layer and / or elements of the distal end region to limit the thickness. Thus, the distal end may include pressure-compression tendons but not any other rigidizing filaments or tendons, such as a rigidizing layer as described herein. This may beneficially increase the flexibility of the apparatus, e.g., by allowing the pressure-compression tendons to slide freely when the compression layer is not being activated by the application of positive or negative pressure, and may reduce the overall stiffness of this region by reducing the number of layers.

[0110] Pressure-compression tendons that extend only lengthwise, e.g. in parallel with the long axis of the rigidizing device, may rigidized the device when pressure is applied along - 28 - SG Docket No.: 13668-727.600the length of the pressure-compression tendons, despite being highly flexible, and sliding freely in the unconstrained configuration. If the pressure-compression tendons are not compressed by the compression layer along their length, and over a sufficient portion of their overall length, slipping and bending may occur in the rigid state. In the examples shown in FIGS.1A-1B and 2A-2B the pressure-compression tendons are shown without any covering or sleeve, so that the compression layer may contact the continuous length of the pressure- compression tendons over the region to be rigidized. As will be described below (in reference to FIGS.4A-4C) in some cases the contacts between the pressure-compression tendons and the compression layer may be intermittent rather than continuous.

[0111] FIGS.3A-3C illustrate another example of a rigidizing apparatus including pressure-compression tendons. As mentioned above, any of these apparatuses may include a plurality of lengths of pressure-compression tendons that extend along the length of the device and may be freely axially slidable. The pressure-compression tendons may be limited or constrained to a radial position around the perimeter of the device. In some examples the pressure-compression tendons may be constrained by a sheath, such as a channel, web, network, ring, cover, braid, etc. that limits the radial movement of the pressure-compression tendons but does not significantly limit the ability of the pressure-compression tendons to move longitudinally as the device is bent or curved, e.g., while steering. In some examples a triax braid may be used as a sheath with the free-floating pressure-compression tendons used for rigidization and / or articulation. The schematic shown in FIG.3A illustrates one example of such a device. In FIG.3A the rigidizing device 300 includes a plurality of lengths of pressure-compression tendons 321, 321’. In any of these apparatuses all or some of the pressure-compression tendons may be configured for steering. For example, a subset of the pressure-compression tendons may be configured for steering the rigidizing distal region and may extend along the length of the apparatus to the proximal end, where they may be configured to couple to a steering mechanism. These steering pressure-compression tendons may also be used for rigidizing the device. Alternatively or additionally, all or a subset of the pressure-compression tendons may be configured for rigidizing but not for steering, and may be configured to extend only partially (e.g., proximally) along the length of the rigidizing device. In some cases, the proximal ends of the pressure-compression tendons may be unattached, e.g., to a steering assembly or sub-assembly, and / or may connect to another pressure-compression tendon.

[0112] In FIG.3A the pressure-compression tendons include a first subset of pressure- compression tendons 321 that are configured as steering pressure-compression tendons and a second subset 321’ of pressure-compression tendons that are configured as rigidizing - 29 - SG Docket No.: 13668-727.600pressure-compression tendons. In this example eight pressure-compression tendons are shown, with four steering pressure-compression tendons and four rigidizing pressure- compression tendons. As mentioned, the steering pressure-compression tendons may also contribute to rigidizing the device. FIG.3B shows an enlarged view of the region (shown as dashed box 3B in FIG.3A) around a steering pressure-compression tendon, and FIG.3C shows an enlarged view of the region (show as dashed box 3C in FIG.3A) around a rigidizing pressure-compression tendon.

[0113] In FIG.3A an inner support tube 315 surrounds an inner lumen 320, and resists compression when the compression layer 323 drives the pressure-compression tendons 321, 321’ radially inward against the inner support tube to rigidize the device. In this example, the pressure-compression tendons are limited from moving radially around the device by being sheathed within a compression material forming the compression layer. Each of the pressure- compression tendons is within a channel through the compression material. The channels 344 have a larger diameter than the outer diameter of the pressure-compression tendons 321, 321’ and may be lubricious to allow relatively unconstrained longitudinal movement of the pressure-compression tendons within the compression material. Thus, when pressure is not being applied to the compression layer, the pressure-compression tendons may slide distally- to-proximally relatively unconstrained within the channels formed through the compression material.

[0114] In FIGS.3A-3C the section through the rigidizing device (e.g., the portion of the rigidizing device that is rigidized by the pressure-compression tendons) includes an elongate length of a flexible inner support tube 315. In some examples, the inner support tube 315 is configured as an inner wall braid, which may include one or more braids, coils, etc. In some cases, the inner support tube comprises a laser cut hypotube that is configured to have a high hoop strength (e.g., resisting crushing) and a high flexibility. Thus, the inner support tube may be optimized for hoop strength to survive external pressurization and remain sufficiently flexible. In some examples the inner support tube comprises a braid, e.g., a flat wire that is braided having a relatively high density (e.g., Programmable Picks Per Inch, PPI).

[0115] Any of the rigidizing devices described herein may also include an outer support tube 301. The outer support tube may be similar to the inner support tube. For example, the outer support tube may be configured as an outer wall braid. In some cases, the outer support tube may include a braid material having a high tensile strength / stiffness but a low bending stiffness. The outer support tube may be optimized for hoop strength to withstand internal pressurization and may remain sufficiently flexible. In some examples the outer support tube may comprise a high PPI aromatic polyamide fiber, e.g. Technora™ braid material. Any of - 30 - SG Docket No.: 13668-727.600the outer support tubes described herein may include an outer coating or layer 331. In some examples, the outer coating comprises an outer wall reflow material that may seal or otherwise prevent or reduce contamination without significantly reducing flexibility. In some examples the outer coating may be a lubricous coating.

[0116] In some examples, the rigidizing device may include one or more sheaths securing the pressure-compression tendons in a radial position around body of the device, while allowing longitudinal (proximal-to-distal) movement relatively unconstrained, as described above. In FIGS.3A-3C the pressure-compression tendons may be sheathed, at least in part, by a sheath 324 comprising one or more filaments that are shown braided around the outside of the inner support tube over and under the pressure-compression tendons to hold them in a fixed radial position. The sheath forming the braid may be formed of a material that has high tensile strength / stiffness but a low bending stiffness e.g., an aromatic polyamide fiber, e.g. Technora™. As mentioned, the braid may be a high PPI braid. The sheath is generally configured to collapse onto the tendons under external pressure (allowing rigidization by activation of the compression layer). Thus, there may be no clearance around the pressure- compression tendons during rigidization, but may be relatively loose when the compression layer is not driven by applied pressure. When the body of the device bends, either when actively bent, e.g., by pulling on one or more of steering tendons (which may include or be a subset of the pressure-compression tendons), or passively bent, e.g., by sliding over a rigid / rigidized inner member having a curved or bent shape (such as a catheter, wire, etc.), the pressure-compression tendons be prevented from moving radially by the sheath as a tensile load is applied. In FIGS.3A-3C the sheath may also include a soft (e.g., low- durometer, such as a material having a durometer of 60 ShoreA or less, 55 ShoreA or less, 50 ShoreA or less, etc.) at least partially encapsulating at least a portion of the pressure- compression tendons, as described above. In some cases, this sheathing material may act as the compression material and may be reflowed over and around the inner wall. The low durometer material may minimize bending stiffness. In some examples the material may be sufficiently tacky to grab the pressure-compression tendons when driven against them by the application of pressure. In some examples the sheathing material (e.g., low-durometer material) may also help prevent permanent disruption of the structure as the device is bent or moved.

[0117] In FIGS.3A-3C the pressure-compression tendons include a subset of pressure- compression tendons configured as steering or articulation tendons. Any appropriate material may be used for the pressure-compression tendons, including the steering / articulation tendons, as mentioned. For example, the pressure-compression tendons may generally be an - 31 - SG Docket No.: 13668-727.600axially stiff cable having a low friction coating, e.g., a tungsten cable with a PTFE coating. The pressure-compression tendons may also include a subset of tendons configured as rigidization tendons that are not configured for steering. The pressure-compression tendons may be very flexible wires or cables that, when constrained, provides axial support. For example, rigidization tendons may be, e.g., 0.009 in OD stainless steel wires. The rigidization tendons may add elasticity to the system when free and may also increase the articulation force, and may be coated to provide a low dynamic friction when free and a high static friction when compressed. In some example the rigidization tendons may be covered / coated with a Pebax heat shrink material (e.g., see, for example, https: / / chamfr.com / product / heat- shrink-pebax-72d-21-clear-0-014-exp-id-quantity-6-bag-p2-014-002-clr / ). The tendons, and in particular the rigidization tendons, may be cables or fibers. In some examples the tendons are solid wires.

[0118] In FIGS.3A-3C the device includes eight pressure-compression tendons, four of which are configured as steering / articulation tendons, and 4 of which are configured as rigidization tendons. FIG.3B shows an enlarged view of the region around a steering / articulation tendon and FIG.3C shows an enlarged view of the region around a rigidization tendon. Thus, subsets of the pressure-compression tendons may be optimized for specific purposes. In some examples, the same tendons may be used for both articulation and rigidization. As mentioned above, in some examples, the tendons may be coated, e.g., with a lubricous coating. In some examples, regions of any lubricous coating may be removed, e.g., by laser ablation, from off the tendons to enhance the friction between the tendon and the compression material / compression layer. Alternatively or additionally a higher-friction coating may be applied over such regions.

[0119] In FIGS.3A-3C the pressure-compression tendons are located on the inner wall and compressed inwards to rigidize, e.g., by applying pressure into the pressure gap 311. In some examples the tensons may instead be embedded on the outer wall and compress outwards (e.g., the pressure gap 311 may be positioned between the inner support tube and the pressure-compression tendons. This configuration may maximize the bending moment that the tendons can apply, and may provide axial stiffness and minimize stretching / wrinkling when rigidized.

[0120] The example shown in FIGS.3A-3C may be rigidized by the application of positive pressure. For example, pressure applied into the pressure gap 311 may drive the compression layer 323 against the soft sheath material(s) 324, 235 and may pinch or compress the pressure-compression tendons. The pressure-compression tendons may then act as a fiber embedded within the wall, resulting in a significant increase in stiffness, locking - 32 - SG Docket No.: 13668-727.600(rigidizing) the shape. Release of the pressure causes the material to expand back outwards, permitting sliding of the pressure-compression tendons and restoring flexibility. Functionally may operate in the same way as rigidizing using a rigidizing layer (e.g., a braid layer) as described in greater detail in reference to FIGS.7A-7B and 8A-8B, below. Prior to pressurization the pressure-compression tendons can slide longitudinally (although constrained from moving radially), resulting in relatively low stiffness. While maintaining pressurization, the pressure-compression tendons are locked in place; in some cases, the greater the positive pressure applied, the stronger the locking force. This effect may be magnified (as compared with rigidizing layers) when using pressure-compression tendons, as the pressure-compression tendons, even in the flexible configuration are limited to movement only in the lengthwise (proximal-to-distal) direction.

[0121] In addition to locking by the application of pressure to compress the pressure- compression tendons, in some examples, the steering tendons, either a separate set of tendons and / or a sub-set (or all) of the pressure-compression tendons, may be locked in place using one or more drive motors or articulation levers. For example, the steering / articulation tendons may all be tensioned together; this will not move the device, but holding enough of the steering / articulation tendons in tension at the same time may prevent steering and may rigidize the steerable region. In some examples this may be used in addition to pressure rigidization.

[0122] The steering / articulation tendons may be manually and / or robotically driven. For example, the steering / articulation tendons may be driven by motors to provide articulation and may be locked in place using pressure for rigidization. Thus, at least over a portion of the apparatus, the use of pressure-compression tendons for both rigidizing and steering may save space and may reduce the device OD (and / or increase the ID). In any of these apparatuses a minimal number of drive motors may be used for tendon control. For example, in some examples two motors may be used per plane of articulation so as to provide smooth, precise control at direction reversal; for example, antagonist tendons can “drive” the mechanism through de-articulation. In some examples one motor per articulation plane may be used and the device may elastically spring back to a straight neutral configuration with the tension tendon being released to accommodate the neutral configuration.

[0123] FIGS.4A-4C illustrate one example of a rigidizing device 400 that includes a plurality of pressure-compression tendons extending lengthwise down the length of the device and a compression layer that may comprise the pressure-compression tendons to rigidize the device. FIG.4A shows the assembled rigidizing device 400 in an unrigidized configuration. The device may be flexibly bent or steered, e.g., by pulling on one or more of - 33 - SG Docket No.: 13668-727.600the pressure-compression tendons, which (in this example) extend the proximal-to-distal length of the device.

[0124] FIG.4B shows the device of FIG.4A with the outer layer(s), including the compression layer, removed to expose the pressure-compression tendons extending the length of the flexible region of the device. The pressure-compression tendons are shown extending lengthwise over the elongate flexible inner support tube 415 that is configured as an inner coil-wound tube comprising a plurality of coils having a high hoop strength over which a flexible, relatively low durometer polymeric material has been reflowed into the gaps between the coils.

[0125] In FIGS.4A-4C the pressure-compression tendons are shown having a plurality of discrete exposed regions 433 along the length of the pressure-compression tendons separated by a plurality of tubular channels 434 within which the pressure-compression tendons may slide. The channels may be bonded or radially constrained to the outside of the inner support tube 415 and the pressure-compression tendons may slide relatively freely within them. The intermittent openings 433 along the length of the pressure-compression tendons may permit the apparatus to be compressed and to make contact with the compression layer, in order to rigidize the device. Although the channels 434 may also be compressed and may collapse onto the pressure-compression tendons to assist in rigidization, it may be particularly beneficial to provide the plurality of exposed openings for the pressure-compression tendons along the length, to grip and lock the pressure-compression tendons. Thus, any of these apparatus may include a plurality of lengths of pressure-compression tendons that are within a plurality of guides / tubes along the length of the device; the guides / tubes may form a plurality of opening along the length of the device that expose the pressure-compression tendon. For example, percentage of the pressure-compression tendons that is exposed (e.g., for contact with the compression layer) may be greater than about 30% (e.g., 30% or more, 35% or more, 40% or more, 45% or more, 50% or more, 55% or more, 60% or more, 65% or more, 70% or more, 75% or more, 80% or more, etc.). Generally, the exposed surface of the pressure-compression tendons may provide the contact surface area between the pressure- compression tendons and the compression layer; in some cases, it is desirable to increase this surface area in order to increase the rigidity of the device in the rigid state, e.g., to prevent slipping. In some examples the tubular channels 434 may be separated to form exposed regions that extend between about 0.5 mm and 10 mm or more along the length of the rigidizing region of the device. In some cases, the tubular channels 434 may be spaced approximately every x mm apart, where x is between about 0.5 mm and about 20 mm or more (e.g., between about 0.5 mm and about 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 7 mm, 10 - 34 - SG Docket No.: 13668-727.600mm, 12 mm, 15 mm, 17 mm, 20 mm, 22 mm, 25 mm, 30 mm, etc.). The spaces (of “exposed regions”) between the channels may also enhance the flexibility of the apparatus when the device is in the flexible configuration and may prevent these sheaths (tubular channels) from bunching up.

[0126] FIG.4C illustrates the device of FIG.4A in a rigidized configuration, in which pressure is maintained to hold the device 400’ in the rigid state. Pressure may be released to restore the device to the flexible configuration. A port 465 is shown on the proximal end.

[0127] FIG, 4D illustrates an example of a pair of nested rigidizing devices 450, 460 including at least one rigidizing device that includes pressure-compression tendons as described herein.

[0128] FIG.5 schematically illustrates one method of operation a rigidizing apparatus using a plurality of pressure-compression tendons as described herein. The device may initially be positioned within the body (in variations used for medical indications), e.g., in the flexible configuration. In some cases, the device may be inserted over or within a guide (e.g., guidewire, guide sleeve, etc.). The distal end region of the device may be steered by rigidizing the device so that the distal end region bends while in a flexible configuration 501. The rigidizing device may be any of the rigidizing devices described herein, including a rigidizing device having an elongate flexible inner support tube extending in a proximal to distal length. The device may be operated in the flexible configuration for positioning within the body or relative to another device, including another rigidizing device, that may be inserted, e.g., into or through the lumen of the rigidizing device. The device may be steered while in the flexible configuration using all or a subset of the pressure-compression tendons in some examples. Alternatively or additionally, the device may be passively steered in the flexible configuration by tracking or following the shape of another device that is inserted into the central lumen of the rigidizing device.

[0129] The rigidizing device may then be rigidized by applying pressure (positive pressure, negative pressure, or in some examples either or both positive and / or negative pressure) to compress a plurality of lengths of pressure-compression tendons that extend lengthwise along the device (in some examples, along the elongate flexible inner support tube) to rigidize the rigidizing device 503. The applied pressure may be maintained to maintain the rigidizing device in a rigid configuration. The amount of pressure applied may be adjusted to adjust the rigidity of the device. The pressure may be applied by applying a positive pressure when applying a fluid (e.g., air, nitrogen, water, saline, etc.) into a pressure gap of the device. The pressure may be maintained actively (e.g., maintaining the pressure - 35 - SG Docket No.: 13668-727.600within a target range) or passively (e.g., sealing the pressure inlet and / or channel to maintain the pressure.

[0130] The pressure may be maintained to keep the device in the rigid configuration for as long as desired. Thereafter, the pressure may be released to convert the rigidizing device back to the flexible configuration 505. The procedure may be repeated as often as desired, e.g., converting between the flexible and rigid configurations. Hybrid rigidizing devices

[0131] Also described herein are apparatuses that include a first region (e.g., a distal region) that is rigidized using a plurality of lengths of pressure-compression tendons and a second region (e.g., a proximal region) that is rigidized using a second mechanism, such as a rigidizing layer. The rigidizing layer may extend as a layer within the device, including adjacent to the elongate flexible inner support tube. The rigidizing layer may be rigidized by pressure, including through the same (or in some cases a different) rigidizing layer that is used to rigidize the length of pressure-compression tendons. The rigidizing layer may include a plurality of filament lengths crossing over and under each other and configured shear relative to each other. The first region may be separate from the second region (and may abut the second rejection or be separated by a gap) or the first and second regions may overlap.

[0132] For example, FIGS.6A-6C illustrate examples of hybrid rigidization devices that include both a plurality of lengths of pressure-compression tendons rigidizing a first region and a rigidizing layer comprising a plurality of filament lengths crossing over and under each other. In FIGS.6A-6C the first region is adjacent to the second region.

[0133] FIG.6A shows an example of a device including a first, distal region 645 that includes a plurality of pressure-compression tendons 621 that extend from the proximal end (not shown) to the distal end 620. In the distal region 645 the pressure-compression tendons 621 may be rigidized as described above, e.g., by being driven by a compression layer (e.g., bladder) of a compression assembly against the elongate flexible inner or outer support tube. In FIG.6A the elongated flexible inner support tube is not visible, but the tendons are shown (through the outer layer(s) of the device) by dashed lines. FIG.6A also includes a proximal region that is configured to be rigidized by a rigidizing layer 609 that comprises a plurality of filament lengths crossing over and under each other and configured shear relative to each other when the device is in the flexible configuration. The pressure-compression tendons in FIG.6A overlap with the rigidizing layer in the second section 647 and may be atop, beneath, or through the elongate flexible inner support tube in the second region.

[0134] FIG.6B shows another example of an apparatus including a first rigidizing region that is rigidized by a plurality of pressure-compression tendons 621’ that extend lengthwise - 36 - SG Docket No.: 13668-727.600along the distal end region (e.g., along the portion of the elongate flexible inner support tube) but do not extend into the second region 647 that includes the rigidizing layer 609. In this example the pressure-compression tendons are configured for rigidizing and flexibility only, but are not configured to actively bend or guide the distal end region, unlike the examples shown in FIGS.6A and 6C. Bending or guiding the distal region could be accomplished by another element, for example, this could be accomplished by elements acting from within the central bore of from outside of the major diameter. In this example the plurality of lengths of pressure-compression tendons may extend substantially parallel to each other and to the long axis of the device, but end before the second region. Thus, the pressure-compression tendons of the rigidizing device shown in FIG.6B are configured as rigidizing tendons.

[0135] FIG.6C illustrates an example of a rigidizing apparatus (e.g., rigidizing device) that includes a distal region 645 with a plurality of pressure-compression tendons extending lengthwise and a proximal region 647 with a rigidizing layer similar to that shown in FIGS. 6A-6B. In FIG.6C the plurality of pressure-compression tendons includes a first subset of rigidizing pressure-compression tendons 621’ that are not configured to steer (or not configured to actively steer) the distal end region, as they extend only partially down the length of the device, and a second subset of pressure-compression tendons 621 configured for steering (e.g., steering / articulation tendons) that extend the full length of the elongate body of the device to the proximal end where they may be controlled (pulled and / or pushed) to steer the distal region. This configuration is similar to the arrangement of pressure-compression tendons shown in FIGS.3A-3C.

[0136] FIG.6D illustrates an example of a rigidizing apparatus that is similar to that shown in FIG.6B, in which the pressure-compression tendons 621’’ are limited to the first (e.g., distal) region 645 and the second region 647 is rigidized by a rigidizing layer. The pressure-compression tendons in FIG.6D are formed into multiple lengths of pressure- compression tendons that extend adjacent to each other, parallel to each other and to the long axis of the device, but at least pairs of pressure-compression tendon lengths could be connected at the proximal end (in an approximately “U” or flattened “U” shape. This connection between the two, in this case, adjacent pressure-compression tendons maybe within the first region 645, at the interface between the first and second regions, or in the second region 647, and may prevent the ends of the pressure-compression tendons from poking through a wall of the device or otherwise can damage to adjacent elements. Alternatively in any of these apparatus the end(s) of the pressure-compression tendons may be blunted and / or encapsulated in a material (e.g., a cap or other covering structure over the - 37 - SG Docket No.: 13668-727.600otherwise free ends of each pressure-compression tendon) that may prevent it from poking through the wall(s) of the device.

[0137] FIG.6E shows an example of a device including a first, distal region 645 that includes a plurality of pressure-compression tendons 621, as discussed above. The pressure- compression tendons 621’’ extend from the distal end to a more proximal region that is within the proximal region 647. The proximal region include a second rigidizing layer 609, such as a plurality of lengths of filament that cross over each other (as a braid, knit, weave, etc.) and may slide freely when in the flexible configuration. The pressure-compression tendons 621 overlap into this proximal region in an overlap region 649. Thus, both the distal region 645 including the pressure-compression tendons 621 and the proximal region including the second rigidizing layer 609 may be rigidized as described above, e.g., by being driven by a compression layer (e.g., bladder) against the elongate flexible inner support tube or outer support tube (e.g., an inner coil-wound tube or an outer coil-wound tube). In FIG.6E the support tube(s) is / are not visible. The region of overlap 649 between the pressure- compression tendons and the second rigidizing layer may be any appropriate length, e.g., between about 1 mm and about 20 cm (e.g., between about 1 mm and 18 cm, between about 5 mm and 18 cm, between about 1 cm and 17 cm, between about 1 cm and 16 cm, between about 1 cm and 15 cm, between about 1 cm and 14 cm, between about 1 cm and 13 cm, between about 1 cm and 12 cm, between about 1 cm and 11 cm, between about 1 cm and 10 cm, between about 1 cm and 9 cm, between 1 cm and 8 cm, between about 1 cm and 7 cm, between 1 cm and 6 cm, between 1 cm and 5 cm, between 1 cm and 4 cm, between 1 cm and 3 cm, etc.). Within the region of overlap 649, the pressure-compression tendons may be atop, beneath, or through the second rigidizing layer. In any of these apparatuses and methods, the pressure-compression tendons may be within a compressible sleeve, channel, tube, etc. or may be uncovered (e.g., unsleeved) over all or a region of their length. In any of these apparatuses the pressure-compression tendons may be within a channel formed in the inner support layer or the outer support layer (or both), e.g., within an inner coil-wound tube and / or an outer coil-wound tube.

[0138] The first (e.g., distal) region that is rigidizable by the pressure-compression tendons may be any appropriate length, and the second (e.g., proximal) region may be any appropriate length. For example, the distal region may be between about 1 cm and 30 cm, between about 1 cm and 28 cm, between about 1 cm and 27 cm, between about 1 cm and 26 cm, between about 1 cm and 25 cm, between about 1 cm and, between about 2 cm and 25 cm, between about 2 cm and 24 cm, between about 2 cm and 23 cm, between about 2 cm and 22 cm, between about 1 cm and 21 cm, between about 2 cm and 20 cm, between about 1 cm and - 38 - SG Docket No.: 13668-727.60018 cm, between about 1 cm and 17 cm, between about 1 cm and 16 cm, between about 1 cm and 15 cm, between about 3 cm and 15 cm, between about 3 cm and 14 cm, between about 3 cm and 13 cm, between about 3 cm and 12 cm, between about 3 cm and 11 cm, between about 3 cm and 10 cm, between about 3 cm and 9 cm, between about 3 cm and 8 cm, between about 3 cm and 7 cm, between about 3 cm and 6 cm, between about 3 cm and 5 cm, etc.). The proximal region may be 5 cm or longer (e.g., 10 cm or longer, 15 cm or longer, 20 cm or longer, 25 cm or longer, 30 cm or longer, 35 cm or longer, 40 cm or longer, 45 cm or longer, 50 cm or longer, etc.). In some examples the proximal region may be much longer than the distal region (e.g., 1.5x or more, 2x or more, 2.5x or more, etc.).

[0139] As mentioned above, any of these apparatuses may include the second rigidizing layer along the entire length of the apparatus (e.g., both the distal end region and the proximal end region) and the pressure-compression tendons may extend in just the distal end region. For example, as shown in FIG.6F. In this example, the tendons 621’’ extend in just the distal region 645’ and fully (or mostly) overlap with the second rigidizing layer 609.

[0140] In any of the apparatuses described herein, including but not limited to those shown in FIGS.6A-6D, the rigidizing layer may be formed by a plurality of filament lengths crossing over and under each other and configured shear relative to each other when in the un-rigidized configuration, as mentioned. FIGS.7A-7B and 8A-8B illustrate examples of rigidizing regions of a device that include a rigidizing layer. Any of these devices may include a region including a rigidizing layer similar to those shown in FIGS.7A-7B and 8A- 8B.

[0141] For example, FIG.7A illustrates an example of a transverse section through an elongate rigidizing device that is configured to be rigidized by a rigidizing layer, showing the arrangements of the many layers that may be included. In this example the rigidizable device 700 is configured to be actuated by the application of a negative pressure (e.g., vacuum). The device 700 shown includes an inner layer (715) that may be reinforced (e.g., by including one or more reinforming members, such as a helically arranged strip, ribbon, wire, etc., which may be braided and / or form rings / loops, etc.), an optional slip layer (713), a pressure gap (711), a rigidizing layer (709), configured in this example as a braid layer, a second pressure gap (707) and an outer layer (701). In some examples a vacuum may be applied between the outer layer and the inner layer to rigidize. For example, a port configured to couple to the source of negative pressure may be located at the proximal end of the device and may be in fluid communication with the gap region 707 between the flexible outer layer 701 and the rigidizing layer 709, e.g., braided layer. Thus, in this example the outer layer may act as a compression layer. These layers are tubular structures that surround an inner lumen 720. FIG. - 39 - SG Docket No.: 13668-727.6007B shows a section through one wall region B of the cylindrical-shaped body of the device. Applying suction may allow the outer layer 701 to be drawn onto the rigidizing layer, causing it to rigidize, limiting or preventing bending of the device.

[0142] Another example of a rigidizable device 2100 is shown in FIGS.8A-8B. In this example the device may also be an elongate, e.g., catheter or tubular-shaped device similar to that in FIGS.7A-7B but may be rigidized by the application of positive pressure. For example, FIG.8A shows a section transverse to the long axis of an elongate rigidizable device. In this example, the layers forming the device are arranged so that an inner reinforced layer 2115 is the most radially-inward layer and may be reinforced, e.g., by a helically wound ribbon, strip, cable, etc. The device may also include an optional slip layer 2113 which may reduce the friction between the inner layer and the more radially-outward layers. The slip layer may be a powder, or it may be a lubricious layer or a layer of lubricious material. A first gap 2112 layer is shown separating the inner layer 2115 and / or the slip layer 2113 from a compression layer, configured in this example as a bladder layer 2121. A second (or intermediate) gap layer 2111 spaces the bladder layer from the rigidizing layer 2109, shown in this example as a braid layer. A third gap layer 2107 is positioned between the rigidizing layer and an outer layer 2101. The outer layer in this example (similar to the inner layer 2115) is reinforced, for example, by a helically wound filament, wire, fiber, band, etc. Although not shown, when actuated by the application of positive pressure between the compression (e.g., bladder) layer and the inner layer, the bladder layer may push the braid layer into the outer layer to rigidize the rigidizing layer. The device includes an inner lumen 2120.

[0143] Both examples of a devices shown in FIGS.7A-7B and 8A-8B may include additional optional layers or components. Further, the compositions of the rigidizing layers may be modified in order to improve performance. In particular the rigidizing layer may be modified to include structures (e.g., knits, wovens, braids, scales, plates, arrays of filaments, granules, and combinations thereof, etc.) that may enhance or improve performance. Rigidizing elements may be used as one type alone, or in conjunction with other rigidizing elements. In some examples the inner and / or outer layers may be modified to enhance or improve performance, including the addition of torsional control components, and / or modulating the durometer of the inner and outer regions of these layers.

[0144] FIG.9 schematically illustrates one method of operating a rigidizing apparatus including a first region that is rigidized using a plurality of pressure-compression tendons and a second region that is rigidized using a rigidizing layer, as described herein. The device may initially be positioned within the body (in variations used for medical indications), e.g., in the - 40 - SG Docket No.: 13668-727.600flexible configuration. In some cases, the device may be inserted over or within a guide (e.g., guidewire, guide sleeve, scope, overtube, etc.). The device may be actively or passively steered so that the device bends with both distal and proximal regions while in the flexible configuration 901. The rigidizing device may be any of the rigidizing devices described herein, including any of the rigidizing devices shown in FIGS.6A-6D. The device may be operated in the flexible configuration for positioning within the body and / or relative to another device, including another rigidizing device, that may be inserted, e.g., into or through the lumen of the rigidizing device. The device may be steered while in the flexible configuration using all or a subset of the pressure-compression tendons in some examples. Alternatively or additionally the device may be passively steered in the flexible configuration by tracking or following the shape of another device that is inserted into the central lumen of the rigidizing device.

[0145] The rigidizing device may then be rigidized by applying pressure (positive pressure, negative pressure, or in some examples a combination of both positive and / or negative pressure) to both the distal region and the proximal region; in the proximal region this may cause a compression layer to compress a plurality of lengths of pressure- compression tendons that extend lengthwise along the proximal region of the device (in some examples, along the elongate flexible inner support tube in the proximal region) and to compress the rigidizing layer against the same or a different compression layer in the proximal region in order to rigidize the rigidizing device 903. The applied pressure may be maintained to maintain the rigidizing device (both the proximal and distal regions) in a rigid configuration. The amount of pressure applied may be adjusted to adjust the rigidity of the device. The pressure may be applied by applying a positive pressure when applying a fluid (e.g., air, nitrogen, water, saline, etc.) into a pressure gap of the device. The pressure may be maintained actively (e.g., maintaining the pressure within a target range) or passively (e.g., sealing the pressure inlet and / or channel to maintain the pressure.

[0146] The pressure may be maintained to keep the device in the rigid configuration for as long as desired. Thereafter, the pressure may be released to convert the rigidizing device back to the flexible configuration 905. The procedure may be repeated as often as desired, e.g., converting between the flexible and rigid configurations. Nested Devices

[0147] In general, any of the rigidizable devices described herein may be configured as nested apparatuses that may be nested to provide enhanced performance. For example, a nested apparatus (system) may include an outer rigidizing device similar to those shown in FIGS.6A-6D and an inner rigidizing device, which may be configured as a rigidizing scope; - 41 - SG Docket No.: 13668-727.600the two rigidizing devices may be axially and rotationally movable with respect to one another. In some examples they may move concentrically, but in some configurations they may be arranged non-concentrically. The outer rigidizing device and the inner rigidizing device can include any of the rigidizing features as described herein. For example, the outer rigidizing device 301 can include a tendon-rigidizing distal end and a proximal end that is rigidized by a rigidizing layer.

[0148] The inner rigidizing device (e.g., scope) can be, for example, configured to receive positive and / or negative pressure to rigidize. Any of these rigidizing devices, including the inner rigidizing device, may include an air / water channel and a working channel and a shape sensing system that can extend with the inner rigidizing device and / or the outer rigidizing device. Additionally, any of these rigidizing devices (including the inner rigidizing device and / or outer rigidizing device) can include a distal section with a camera, lights, and may be steerable. In some cases, the steerable distal end may be steerable using any of the pressure-compression tendons as described herein. Alternatively or additionally, one of the nested device may include a steerable end with linkages. In another example, the camera and / or lighting can be delivered in a separate assembly (e.g., the camera and lighting can be bundled together in a catheter and delivered down the working channel and / or an additional working channel to the distal-most end). The feature of any of these apparatuses may include or be incorporated into apparatuses including flexible external working channels can be incorporated (as described in PCT Patent Application No. PCT / US2023 / 067072, titled “EXTERNAL WORKING CHANNELS FOR ENDOSCOPIC DEVICES,” and filed on May 16, 2023, herein incorporated by reference in its entirety.

[0149] The inner lumen of the first, outer rigidizable device can form a gap or interface into which the second, inner, rigidizable device may be positioned. This gap or interface region can have any appropriate dimensions, so that an annular space (d) remains around the second, inner, rigidizable device when inserted into the first, outer, rigidizable device. In some examples, when the inner rigidizable device is centered in the lumen of the outer rigidizable device, space on either side of the inner rigidizable device, e.g., the radial gap, may be between about 0.001”-0.050”, such as 0.0020”, 0.005”, or 0.030” wide. The inner surface of the outer rigidizing device and / or the outer surface of the inner rigidizable device may be a low friction surface and may include, for example, powder, coatings (for example, hydrophilic or hydrophobic), or laminations to reduce the friction. In some examples, a seal may be present between the inner device and the outer rigidizable device, and the intervening space can be pressurized, for example, with fluid or water, to create a hydrostatic bearing. In - 42 - SG Docket No.: 13668-727.600other examples, there can be seals between the inner rigidizable device and outer rigidizable device, and the intervening space can be filled with small spheres to reduce friction.

[0150] The inner rigidizable device and outer rigidizable device can move relative to one another and alternately rigidize so as to transfer a bend or shape down the length of the nested system. For example, the inner device can be inserted into a lumen and bent or steered into the desired shape. Pressure can be applied to the inner rigidizing device to cause the rigidizing layer to rigidize the inner rigidizable device in whatever configuration curve bend it had when the pressure was applied. The rigidizable device (for instance, in a flexible state) can then be advanced over the rigid inner rigidizable device. When the outer rigidizable device is sufficiently advanced relative to the inner rigidizable device, pressure (e.g., positive or negative pressure) can be applied to the outer rigidizable device to cause the rigidizing layers to rigidize to fix the shape of the outer rigidizable device. The inner rigidizable device can be transitioned to a flexible state, advanced, and the process repeated. Although the system is described as including an inner rigidizable device configured as a scope, it should be understood that other configurations are possible. For example, the system might include two overtubes, two catheters, or a combination of overtube, catheter, and scope.

[0151] FIGS.10A-10H are shown and described to illustrate generally the nested systems 1000 and methods of operating them that may be performed with any of the rigidizable devices described herein. In these examples the outer rigidizing device 1001 may be rigidizing and may include a steerable distal end that is rigidizing and / or steered using pressure-compression tendons at the distal end. In some cases, the proximal end may be rigidized using a rigidizing layer as described above. The inner rigidizing member 1003 may also include a distal region rigidizable by pressure-compression tendons and a proximal rigidizable region including a rigidizing layer. The outer rigidizing device may be actively steered (e.g., using steering / articulation tendons) or passively steered.

[0152] With respect to FIGS.10A-10H, the example nested apparatus shown may be rigidized by any appropriate method, including, but not limited to, the application of positive and / or negative pressure to one or both rigidizing members. The modifications to the rigidizing member, torsional stiffness, and / or durometer of the inner and / or outer layers (tubes) of these rigidizable devices may provide enhanced movement and functionality of the nested devices described herein when performing a method similar to that shown in FIGS. 10A-10H. Indications and Methods for Use

[0153] The apparatuses (devices, systems) described herein may be used in any appropriate body region. For example, these apparatuses may be configured as catheters, - 43 - SG Docket No.: 13668-727.600sheaths, scopes (e.g., endoscopes), wires, overtubes, cannulas, trocars or laparoscopic instruments and / or may be included as part of a nested pair of devices (one or more of which are rigidizable). For example, any of the apparatuses described herein may be configured for use in one or more of: the neurovasculature (e.g., aortic arch, subclavian, carotid, vertebral, basilar, posterior cerebral, circle of Willis, middle cerebral, anterior cerebral, etc.), the upper GI tract (mouth esophagus, stomach, pylorus, bile duct and pancreatic duct, etc.), the small bowel (e.g., small intestine, duodenum, jejunum, ilium, etc.), the lower GI tract (rectum, regions of colon, e.g., sigmoid, descending, transverse, ascending, cecum, ileocecal valve, etc.), the urinary tract (urethra, bladder, kidneys, ureters, etc.), the peripheral vasculature (e.g., femoral, iliac, mesenteric, lumbar, renal, celiac trunk, hepatic, thoracic, etc.), the cardiac region (e.g., aorta, right coronary artery, left coronary artery, etc.), the left heart (e.g., aorta, aortic valve, left ventricle, etc.), the right heart (e.g., vena cava, right atrium, left atrium, mitral valve, coronary sinus, tricuspid valve, right ventricle, pulmonary valve, pulmonary vasculature, etc.) and / or the right pulmonary region (e.g., mouth, larynx, trachea, bronchial tree and lobes etc.).

[0154] Thus, any of the apparatuses (and methods of using them) described herein may be used with, or as part of, a catheter, an endoscope (including, but not limited to colonoscopes, bronchoscope, colposcope, cystoscope, esophagoscope, gastroscope, laparoscope, thoracoscope, enteroscope, etc.), overtube, etc. These apparatuses and methods may be used with a robotic system, including a robotically controlled endoscope. Robotic systems may be steered and / or advanced robotically. Systems may be used with both manual and robotic elements. In some examples, the robotic system may control the operation (e.g., advancing, retracting, and / or actuating) of one or more tools to be used within an external working channel, including any of the tools or tool pairs described herein. Any of the apparatuses described herein may be used with a robotic system, including a robotic endoscope system. Variations

[0155] Any of the apparatuses and method described herein, unless the context indicates otherwise, may be configured rigidize by the application of positive pressure, including relatively high pressure (e.g., up to 4 atm, 5 atm, 6 atm, 7 atm, 8 atm, 9 atm, 10 atm, 30 atm, 50 atm, etc.). Alternatively, any of the apparatuses described herein, unless the context makes it clear otherwise, may be configured to rigidize by the application of negative pressure (e.g., vacuum / suction). Similarly, any of these apparatuses and methods may include any of the variations illustrated and described below with respect to FIGS.12A-12I, 13A-13B, 14A- 14B, 15A-15E, 16A-16F, 17A-17B, 18A-18B, 19A-19B, 20A-20B, 21A-21B, and 22A-22B. - 44 - SG Docket No.: 13668-727.600

[0156] As described above, in any of these apparatuses, at least the distal end region is configured to include a plurality of length of pressure-compression tendons. The pressure- compression tendon may act over a certain region (for example, a distal region), or over the entire length. In some examples the pressure-compression tendons are formed of a plurality of different individual length of tendon that extend over at least a discrete portion of the length, e.g., over the distal end region. The pressure-compression tendons may be arranged as multiple long (e.g., full length) pressure-compression tendons that extend the length of the device, or it may include a plurality of shorter longitudinal lengths pressure-compression tendon that extend in a plurality of longitudinal sections, as illustrated in FIGS 13A-13B and 14A-14B.

[0157] In some examples the pressure-compression tendons are discrete or semi-discrete elements, as shown in FIGS.12A, 12F and 12G. In some examples the pressure-compression tendons may be individual lengths tendons, as shown in FIG.12A. In some cases, sets of pressure-compression tendons may be formed of discrete lengths of tendons, as shown in FIGS.12F and 12G. In FIG.12F, pairs of lengths of pressure-compression tendons are formed by U-shaped tendons. Other shapes may be used, including but not limited to V- shaped, square-shaped, etc. In any of these examples the ends of the tendons may be configured to be atraumatic, to prevent poking through any of the layer of the apparatus. For example, the ends of the pressure-compression tendons may be blunted (e.g., formed into a ball or otherwise capped). In some cases, the end(s) of the pressure-compression tendons may be coupled to a retainer or structure (e.g., ring, etc.) or combined with a layer (e.g., the filament(s) of the second rigidizing layer), e.g., by welding, fusing, or otherwise, to prevent them from damaging the apparatus and / or the patient. In some cases, the end(s) may be free to move (e.g., slide longitudinally) within the apparatus. In some cases, the free end of these pressure-compression tendons, e.g., in FIG.12F, may be arranged distally and may couple to a cap or ring at the distal end region.

[0158] In FIG.12G the pressure-compression tendons are formed by bent lengths (e.g., U-shaped, V-shaped, square shaped, etc.) that may alternate directions, as shown.

[0159] The pressure-compression tendons may be wires or lengths of wire that extend longitudinally. In any of these examples the tendons may be positioned within a plurality of channels or sheaths (e.g., tubes 1234, etc.). Alternatively or additionally, in some examples the pressure-compression tendons may be a longer length of wire that is co-joined or that zig- zags, or loops. For example, the pressure-compression tendons shown in FIG.12B are formed of a single wire that has multiple lengths of pressure-compression tendons that zig- zag proximally to distally. FIG.12C shows an example of a plurality of pressure-compression - 45 - SG Docket No.: 13668-727.600tendon lengths that are formed from a single wire (monofilament or multi-filament / braid) having a proximal-to-distal square shape. In FIGS.12A-12G the pattern of pressure- compression tendons is shown in a flat configuration; in use, these patterns may be wrapped around the circumference of a rigidizing device, as shown in FIG.12H. In FIG.12H the rigidizing device includes a distal end region having a plurality of pressure-compression tendons (such as an of those shown in FIGS.12A-12D) around the circumference of the device. The pressure-compression tendons may be formed of a continuous loop of material (e.g., the free ends shown in FIG.12B, 12C, and / or 12E may be joined together). In use, the distal end of the device may also include a compression layer and one or more support layers (e.g., an inner flexible tube and / or outer flexible tube), as described above. The distal end region 1245 of the rigidizing device may therefore be highly flexible (as shown in FIG.12I) in bending, but may become very stiff once rigidized. The proximal end region 1247 may also be rigidizing.

[0160] As mentioned above, the ends of the pressure-compression tendons may be free- floating, or the ends may be captured or contained. The pressure-compression tendons may be for rigidizing only, or their functionality may be combined with steering functionality.

[0161] FIGS.13A and 13B illustrate alternative examples of pressure-compression tendons arranged along the longitudinal length of a rigidizing device, either at just the distal end or along the full length (or most of the length). FIG.13A shows an example of a length of pressure-compression tendon 1321, configured as a wire. In some examples, as shown in FIG.13B a plurality of these short-length pressure-compression tendons are arranged longitudinally down the length of the elongate body (other components of the rigidizing device are omitted to illustrate the arrangement of the pressure-compression tendons). In this example, multiple non-overlapping (though in some cases they may overlap) different discrete lengths of pressure-compression tendons extend around the circumference and down the longitudinal length.

[0162] FIGS.14A and 14B illustrate another example of a pressure-compression tendon (shown in an enlarged view in FIG.14A) configured as a loop 1421 of wire (or other appropriate material, including, for example, cable, fiber, metal, ceramic, plastic, elastomer). A plurality of these loops 1421 may be arranged along the length of the device, as shown in FIG.14B. The loops of wire may be configured to allow the device to flex (particularly where the ends of the loop are free to extend distally and proximally as the device bends) and may lack sharp of pointed free ends that may otherwise risk damaging the device.

[0163] In some examples the apparatus may be configured to be pressured to apply a radial outward force. For example, FIG.15A includes an outer support tube 1501 (shown as a - 46 - SG Docket No.: 13668-727.600coil-reinforced tube), and inner support tube 1515 (also shown as a coil-reinforced tube), a compression layer 1507 (shown as a bladder) a rigidizing layer 1509 including a plurality of strand lengths that cross over and under each other, and a pressure-compression tendon 1521. In this arrangement the tendon may be driven against the rigidizing layer and against the outer support tube by expanding (e.g. applying positive pressure). In some examples the device may be configured to rigidize with just the pressure-compression tendon 1521 and without the rigidizing layer, as shown in FIG.15C. Alternatively, in some variations the device may include a rigidizing layer 1509, but may wind or pass the pressure-compression tendon through the rigidizing layer, as shown in FIG.15D. Element 1507 is shown as a complete out-and-back bladder, but the system could also be configured in which it is a single layer, and the other layer of the pressurized system is, for example, the sealed layer 1501 or 1515.

[0164] In some examples the apparatus may be configured to be pressured to apply a radial inward force. For example, FIG.15B is configured to apply a radially inward force to drive the pressure-compression tendons (and optionally as shown in FIG.15B, a rigidizing layer 1509) against the outer support tube 1501 to rigidize the device.

[0165] In some examples, the apparatus is configured to be pressured to apply both a radial outward and a radially inward force, as shown in FIG.15E. In this example a pair of overlapping pressure-compression tendons 1521, 1521’ are shown with a compression layer 1507 between the two.

[0166] The compression layer 1507 shown in the examples of FIGS.15A-15E is configured to be pressurized against the inner tube 1515 or outer tube 1501.

[0167] FIGS.16A-16F illustrate one example of an apparatus that includes pressure- compression tendons at the distal end for enhancing the rigidity of the pressure-rigidizing apparatus in the rigid state without significantly reducing flexibility in the flexible state(s). Features illustrated in FIGS.16A-16F may be used in any of these apparatuses. In FIG.16A the pressure-compression tendons maybe formed as U-shaped lengths (though continuous, back-and-forth lengths may be used, as described above), having a length 1680, and each tendon length includes a proximal end 1681 and a distal end 1682. In some examples, the pressure-compression tendons, or a region of the pressure-compression tendons such as the proximal end region of the pressure-compression tendons, could have a surface configured to be easy to grip (uncoated cable / wire). The geometry of the pressure-compression tendons could be configured to maximize the surface area that could be grabbed. In some cases, the proximal end region of the pressure-compression tendons may be flattened or broadened (e.g., the bend or loop region) to enhance gripping. In any of these examples the pressure- - 47 - SG Docket No.: 13668-727.600compression tendons could have a low-friction outer surface, such as a PTFE (e.g., ePTFE) coating to reduce friction and allow the device to more easily bend. In some cases, the distal end of the pressure-compression tendons may be configured to have a low-friction outer surface.

[0168] As mentioned above, any of these apparatuses, the tendon maybe two-fold or more (e.g., 2X) the length of the bending section, such as greater than 20 cm. The pressure- compression tendons may be sufficiently stiff to transmit axial force over the unconstrained length without buckling. As mentioned, the pressure-compression tendons may be cable (multi-filament) and / or single-filament wire.

[0169] As mentioned above, in some cases a sleeve or channel 1685 (e.g., guide, jacket, tube, etc.) may be included over each pressure-compression tendons and / or adjacent pairs of pressure-compression tendons, as shown in FIGS.16B and enlarged detail in FIG.16C. Thus, in some cases adjacent tenons may be coupled together to share a jacket, as shown. The sleeve may be formed of any appropriate material, such as but not limited to polyimide. The sleeve may be applied in any appropriate manner. For example, the sleeve may be applied by sliding the tube (e.g. polyimide tube) over the legs of two formed tendons. The sleeve may be as thin as possible whilst still being durable enough to secure the legs together, and may provide a lubricious lumen that allows the legs to translate linearly independently form one and other, while restricting radial movement.

[0170] The sleeve may be free to slide within the apparatus as it is bent. In general, the sum of distal and proximal unconstrained lengths of the pressure-compression tendons may be greater than the total maximum anticipated translation of any tendon due to bending. The pressure-compression tendons may be sufficiently stiff so that they can survive buckling over this total unconstrained length. In any of these examples one end of the sleeve may be bonded to the pressure-compression tendon(s) to lock their position.

[0171] FIG.16D shows an assembly including a plurality of pressure-compression tendons that have been combined into sleeves on adjacent legs as described above, forming a tubular layer of pressure-compression tendons. In FIG.16D, eight sets of tendons are shown; fewer (e.g., between 3-8) could be used, e.g., if stiffer tendons are used to translate over a longer unconstrained distance. In some cases, more tendons (e.g., between 9-16 or more) could be used if the unconstrained distance was shorter, and if highly flexible tendons are used. More tendons may significantly improve rigidity, but may increase manufacturing complexity.

[0172] FIG.16E shows coupling of the free ends of the pressure-compression tendons to a cap (e.g., tip or tip region 1688). As mentioned, the tip may prevent damage from the - 48 - SG Docket No.: 13668-727.600potentially sharp ends of the tendons. In some cases, the tip may constrain the distal ends of the tendons to a predetermined radial (e.g., clock) position. In any of these apparatuses, the tip could be laser cut from tube or formed. The tip may be a ring, as shown. The tip may have a sinusoidal shape. In FIG.16E, each set of two tendons is shown laser welded in place to the tip 1688. The tip may be configured to maximize surface area and minimize hoop stiffness so that it can be reflowed into a flexible tip. Alternatively in some examples, the distal ends of the pressure-compression tendons may be cripped or ball weld together, and reflowed into the composite structure of the apparatus.

[0173] FIG.16F shows an example of a portion of a distal end region of a rigidizing apparatus including the pressure-compression tendons and cap 1688 shown in FIGS.16A- 16E. The proximal region includes the second rigidizing layer 1609 and the distal region includes the pressure-compression tendons 1611. The compression layer 1623 is shown under the tendons and also underlies the second rigidizing layer 1609. This example does not show an outer support layer, e.g., outer coil-wound tube, which may be included. The pocket can be created by periodically heat-staking a film, with areas between heat staking being the pocketed areas in which the tendons can be located but still moveable.

[0174] FIGS.17A-17B illustrate another example of a rigidizing apparatus including a set of pressure-compression tendons 1711 that are formed by a single wire (or cable) arranged in a sinusoidal loop (shown in FIG.17A) that include longitudinally-arranged (as in any of these apparatus, with between + / -10 degree of angle relative to the long axis, or less, such as + / - 9 degrees or less, + / - 8 degrees or less, + / - 7 degrees or less, + / - 6 degrees or less, + / - 5 degrees or less, + / - 4 degrees or less, etc.). This example does not include a cap, but could. The pressure-compression tendons may be bare or may be within a jacket / sleeve as described above. The compression layer 1723 is shown beneath the pressure-compression tendons, but in some cases may be above the pressure-compression tendons.

[0175] FIGS.18A-18B show another example of a rigidizing apparatus including a plurality of pressure-compression tendon lengths. In this example the pressure-compression tendons 1811 extend into the second rigidizing layer 1809 (which may be formed of a plurality of lengths of filaments that cross over each other, e.g., mesh, knit, weave, etc.), and a compression layer (e.g., bladder 1823). In FIG.18A the apparatus includes an inner support layer (e.g., inner coil-wound tube 1830) and an outer support layer (e.g., outer coil-wound tube 1831), which has been partially removed. FIG.18B shows the rigidizing apparatus with the outer support layer fully removed. In this example the pressure-compression tendon lengths are free floating or may be threaded within the second rigidizing layer 1809 (e.g., which may be a braid). - 49 - SG Docket No.: 13668-727.600

[0176] In any of these apparatuses the pressure-compression tendons may be held within the inner and / or outer support layers and may be locked in place to rigidize when the compression layer is driven against the support layer, e.g., outer and / or inner. For example, FIGS.19A-19B illustrate an apparatus including an outer support layer, configured as an outer coil-wound tube in which a helically-wrapped coil (not shown) of material, such as a filament of metallic wire, is embedded within the layer to limit or prevent expansion / collapse of the support layer. In FIG.19A the outer support layer 1931 is made semi-transparent, showing pockets or channels 1987 formed within the layer. FIG., 19B shows the same region of the outer support layer that is not transparent, showing the openings 1988 into the support layer into which the pressure-compression tendons may be placed, so that they may slide when in the flexible state but may be compressed to rigidize the apparatus by the compression layer when pressure is applied.

[0177] FIGS.20A-20B show another example of a support layer (e.g., outer support layer, such as an outer coil wound tube) that is configured to include pockets for the pressure- compression tendons. In general, these channels or pockets may be formed by any appropriate manner. In some cases, the channels for the pressure-compression tendons may be formed in the support layer as a multi-lumen extrusion. For example, the channels may be formed using PTFE-coated wires (having a larger outer diameter than the pressure- compression tendons) that are included when wrapping the device to form the outer (or in some cases, inner) support layer. The support layer may then be re-flowed over / around the wires and the wires maybe removed, leaving the pockets. In some examples a separate sheet, film or coating may be attached to the inner diameter of the support layer at certain positions.

[0178] FIG.20A schematically illustrates an example of a support layer that is configured to include pockets 2087 (shown in the cross-sectional view of FIG.20B) for the pressure- compression tendons as described. In examples in which the support layer is an outer support layer the pockets may be formed radially inward of the coil-wound support (e.g., wire). In examples in which the support layer is an inner support layer the pockets may be formed radially outward of the coil-wound supports. The distal end region includes openings 2088 to receive the tendons. FIGS.21A-21B illustrate an example of a distal end of a rigidizing apparatus including pockets 2187 in the outer support layer 2131 holding tendons 2123. The pockets extend proximally over the region including the second rigidizing layer 2109 and the same compression layer 2111 may be used to rigidize both the second compression layer and the tendons.

[0179] In any of these apparatuses the pressure-compression tendons may be configured as (or may be connected to) a torsion spring. This configuration may modify the proximal end - 50 - SG Docket No.: 13668-727.600of the pressure-compression tendon(s) so that it / they are easier to grab and / or less stiff when the apparatus is rigidized. In FIG.22A a portion of a pressure-compression tendon is shown configured as a torsion spring (e.g., the proximal end of the tendon may be configured as a torsion spring). FIGS.22A and 22B show two lengths of pressure-compression tendon that are configured to wrap at the proximal end in one or more loops 2224 to form a torsion spring. This may allow the tendons to more easily translate independently, reducing bending stiffness when the device is in flexible mode. This configuration may also maximize the surface area available to “grab” the tendon pair when the device rigidizes, as this looped region may be compressed by the compression layer. Robotic apparatuses

[0180] The rigidizing apparatuses described herein may be configured as part of a robotic system or for use with robotic apparatuses. In some examples the rigidizing apparatus may be configured as an outer tubular member that is robotically controlled, e.g., configured as a robotically controlled overtube and / or endoscope assembly. FIG.11 shows an exemplary apparatus 3100, including a rigidizing device configured as an overtube 3112; the system may optionally include an inner endoscope 3110. The overtube and inner endoscope can be separately or collectively be robotically controlled or manipulated (e.g., steering, movement, rotation, etc. including in some examples, rigidizing). In some versions, some elements may be robotically controlled, and others may be manually controlled. The overtube and inner endoscope may be configured as illustrated in any of the examples described above, and may have the same general construction, or may be of different constructions. As shown in FIG. 11, the outer overtube 3112 and the inner endoscope 3110 may be terminated together into a common structure, such as a cassette 3157 having an interior volume 3182 and a port or ports 3125y to connect to external elements (e.g., water, suction, tools, etc.). The outer overtube 3100 can be movable with respect to the endoscope 3110 by rotation of a driver mounted to the cassette 3157. The system may include actuators 3171a, 3171b that may connect to cables 3163a, 3163b respectively, to steer (e.g., bend or deflect) the tip of the endoscope 3110 (and / or outer overtube 3112). Other steering mechanisms (e.g., pneumatics, hydraulics, shape memory alloys, EAP (electro-active polymers), or motors) are also possible. The cassette 3157 can further include bellows 3103a, 3103b that may connect to the pressure gap of the endoscope 3110 and the overtube 3112, respectively to drive fluid through pressure lines 3105z, in variations for either the endoscope and / or the overtube that are configured to rigidize when pressure is applied. As shown in this example, the cassette 3157 can include eccentric cams 3174a, 3174b to control bellows 3103a, 3103b. Alternatively, one or more linear actuators can be configured to actuate the bellows. As another alternative, the devices - 51 - SG Docket No.: 13668-727.600can be rigidized and de-rigidized through one or more pumps or pressure sources (e.g., via pressure line 3105z).

[0181] All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. Furthermore, it should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein and may be used to achieve the benefits described herein.

[0182] Any of the methods (including user interfaces) described herein may be implemented as software, hardware or firmware, and may be described as a non-transitory computer-readable storage medium storing a set of instructions capable of being executed by a processor (e.g., computer, tablet, smartphone, etc.), that when executed by the processor causes the processor to control perform any of the steps, including but not limited to: displaying, communicating with the user, analyzing, modifying parameters (including timing, frequency, intensity, etc.), determining, alerting, or the like. For example, any of the methods described herein may be performed, at least in part, by an apparatus including one or more processors having a memory storing a non-transitory computer-readable storage medium storing a set of instructions for the processes(s) of the method.

[0183] While various embodiments have been described and / or illustrated herein in the context of fully functional computing systems, one or more of these example embodiments may be distributed as a program product in a variety of forms, regardless of the particular type of computer-readable media used to actually carry out the distribution. The embodiments disclosed herein may also be implemented using software modules that perform certain tasks. These software modules may include script, batch, or other executable files that may be stored on a computer-readable storage medium or in a computing system. In some embodiments, these software modules may configure a computing system to perform one or more of the example embodiments disclosed herein.

[0184] As described herein, the computing devices and systems described and / or illustrated herein broadly represent any type or form of computing device or system capable of executing computer-readable instructions, such as those contained within the modules described herein. In their most basic configuration, these computing device(s) may each comprise at least one memory device and at least one physical processor.

[0185] The term “memory” or “memory device,” as used herein, generally represents any type or form of volatile or non-volatile storage device or medium capable of storing data - 52 - SG Docket No.: 13668-727.600and / or computer-readable instructions. In one example, a memory device may store, load, and / or maintain one or more of the modules described herein. Examples of memory devices comprise, without limitation, Random Access Memory (RAM), Read Only Memory (ROM), flash memory, Hard Disk Drives (HDDs), Solid-State Drives (SSDs), optical disk drives, caches, variations or combinations of one or more of the same, or any other suitable storage memory.

[0186] In addition, the term “processor” or “physical processor,” as used herein, generally refers to any type or form of hardware-implemented processing unit capable of interpreting and / or executing computer-readable instructions. In one example, a physical processor may access and / or modify one or more modules stored in the above-described memory device. Examples of physical processors comprise, without limitation, microprocessors, microcontrollers, Central Processing Units (CPUs), Field-Programmable Gate Arrays (FPGAs) that implement softcore processors, Application-Specific Integrated Circuits (ASICs), portions of one or more of the same, variations or combinations of one or more of the same, or any other suitable physical processor.

[0187] Although illustrated as separate elements, the method steps described and / or illustrated herein may represent portions of a single application. In addition, in some embodiments one or more of these steps may represent or correspond to one or more software applications or programs that, when executed by a computing device, may cause the computing device to perform one or more tasks, such as the method step.

[0188] In addition, one or more of the devices described herein may transform data, physical devices, and / or representations of physical devices from one form to another. Additionally or alternatively, one or more of the modules recited herein may transform a processor, volatile memory, non-volatile memory, and / or any other portion of a physical computing device from one form of computing device to another form of computing device by executing on the computing device, storing data on the computing device, and / or otherwise interacting with the computing device.

[0189] The term “computer-readable medium,” as used herein, generally refers to any form of device, carrier, or medium capable of storing or carrying computer-readable instructions. Examples of computer-readable media comprise, without limitation, transmission-type media, such as carrier waves, and non-transitory-type media, such as magnetic-storage media (e.g., hard disk drives, tape drives, and floppy disks), optical-storage media (e.g., Compact Disks (CDs), Digital Video Disks (DVDs), and BLU-RAY disks), electronic-storage media (e.g., solid-state drives and flash media), and other distribution systems. - 53 - SG Docket No.: 13668-727.600

[0190] A person of ordinary skill in the art will recognize that any process or method disclosed herein can be modified in many ways. The process parameters and sequence of the steps described and / or illustrated herein are given by way of example only and can be varied as desired. For example, while the steps illustrated and / or described herein may be shown or discussed in a particular order, these steps do not necessarily need to be performed in the order illustrated or discussed.

[0191] The various exemplary methods described and / or illustrated herein may also omit one or more of the steps described or illustrated herein or comprise additional steps in addition to those disclosed. Further, a step of any method as disclosed herein can be combined with any one or more steps of any other method as disclosed herein.

[0192] The processor as described herein can be configured to perform one or more steps of any method disclosed herein. Alternatively or in combination, the processor can be configured to combine one or more steps of one or more methods as disclosed herein.

[0193] When a feature or element is herein referred to as being "on" another feature or element, it can be directly on the other feature or element or intervening features and / or elements may also be present. In contrast, when a feature or element is referred to as being "directly on" another feature or element, there are no intervening features or elements present. It will also be understood that, when a feature or element is referred to as being "connected", "attached" or "coupled" to another feature or element, it can be directly connected, attached or coupled to the other feature or element or intervening features or elements may be present. In contrast, when a feature or element is referred to as being "directly connected", "directly attached" or "directly coupled" to another feature or element, there are no intervening features or elements present. Although described or shown with respect to one embodiment, the features and elements so described or shown can apply to other embodiments. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed "adjacent" another feature may have portions that overlap or underlie the adjacent feature.

[0194] Terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. For example, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items and may be abbreviated as " / ". - 54 - SG Docket No.: 13668-727.600

[0195] Spatially relative terms, such as "under", "below", "lower", "over", "upper" and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is inverted, elements described as "under”, or "beneath" other elements or features would then be oriented "over" the other elements or features. Thus, the exemplary term "under" can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms "upwardly", "downwardly", "vertical", "horizontal" and the like are used herein for the purpose of explanation only unless specifically indicated otherwise.

[0196] Although the terms “first” and “second” may be used herein to describe various features / elements (including steps), these features / elements should not be limited by these terms, unless the context indicates otherwise. These terms may be used to distinguish one feature / element from another feature / element. Thus, a first feature / element discussed below could be termed a second feature / element, and similarly, a second feature / element discussed below could be termed a first feature / element without departing from the teachings of the present invention.

[0197] In general, any of the apparatuses and methods described herein should be understood to be inclusive, but all or a sub-set of the components and / or steps may alternatively be exclusive and may be expressed as “consisting of” or alternatively “consisting essentially of” the various components, steps, sub-components or sub-steps.

[0198] As used herein in the specification and claims, including as used in the examples and unless otherwise expressly specified, all numbers may be read as if prefaced by the word "about" or “approximately,” even if the term does not expressly appear. The phrase “about” or “approximately” may be used when describing magnitude and / or position to indicate that the value and / or position described is within a reasonable expected range of values and / or positions. For example, a numeric value may have a value that is + / - 0.1% of the stated value (or range of values), + / - 1% of the stated value (or range of values), + / - 2% of the stated value (or range of values), + / - 5% of the stated value (or range of values), + / - 10% of the stated value (or range of values), etc. Any numerical values given herein should also be understood to include about or approximately that value, unless the context indicates otherwise. For example, if the value "10" is disclosed, then "about 10" is also disclosed. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. It is also - 55 - SG Docket No.: 13668-727.600understood that when a value is disclosed that "less than or equal to" the value, "greater than or equal to the value" and possible ranges between values are also disclosed, as appropriately understood by the skilled artisan. For example, if the value "X" is disclosed the "less than or equal to X" as well as "greater than or equal to X" (e.g., where X is a numerical value) is also disclosed. It is also understood that the throughout the application, data is provided in a number of different formats, and that this data, represents endpoints and starting points, and ranges for any combination of the data points. For example, if a particular data point “10” and a particular data point “15” are disclosed, it is understood that greater than, greater than or equal to, less than, less than or equal to, and equal to 10 and 15 are considered disclosed as well as between 10 and 15. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0199] Although various illustrative embodiments are described above, any of a number of changes may be made to various embodiments without departing from the scope of the invention as described by the claims. Optional features of various device and system embodiments may be included in some embodiments and not in others. Therefore, the foregoing description is provided primarily for exemplary purposes and should not be interpreted to limit the scope of the invention as it is set forth in the claims.

[0200] The examples and illustrations included herein show, by way of illustration and not of limitation, specific embodiments in which the subject matter may be practiced. As mentioned, other embodiments may be utilized and derived there from, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Such embodiments of the inventive subject matter may be referred to herein individually or collectively by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept, if more than one is, in fact, disclosed. Thus, although specific embodiments have been illustrated and described herein, any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description. - 56 - SG Docket No.: 13668-727.600

Claims

CLAIMS What is claimed is:

1. A rigidizing device comprising: an elongate body comprising a support layer; a proximal region of the elongate body having a rigidizing layer comprising a plurality of strand lengths that cross over each other; a distal region of the elongate body comprising a plurality of lengths of pressure- compression tendons extending proximally in a long axis of the elongate body; and a compression layer configured to receive positive and / or negative pressure to rigidize the elongate body by driving the rigidizing layer against the support layer, and by preventing or limiting axial movement of the plurality of lengths of pressure-compression tendons, wherein the rigidizing device is configured to change between a flexible configuration and a rigid configuration.

2. The rigidizing device of claim 1, wherein plurality of strand lengths cross over and under each other cross at braid angle of greater than 5 degrees relative to a longitudinal axis of the flexible tube.

3. The rigidizing device of claim 1, wherein the plurality of lengths of pressure- compression tendons extend proximally in the axis of the elongate body approximately parallel to the length of the elongate body.

4. The rigidizing device of claim 1, wherein the compression layer extends along both the proximal region and the distal region.

5. The rigidizing device of claim 1, wherein the compression layer comprises a bladder layer.

6. The rigidizing device of claim 1, wherein at least some of the lengths of pressure- compression tendons extend proximally to a proximal end of the rigidizing device and are configured for steering the distal end of the elongate flexible inner support tube.

7. The rigidizing device of claim 1, wherein the lengths of pressure-compression tendons are unattached at their proximal ends. - 57 - SG Docket No.: 13668-727.6008. The rigidizing device of claim 1, wherein at least some of the lengths of pressure- compression tendons are connected to each other at their proximal ends.

9. The rigidizing device of claim 1, wherein the plurality of lengths of pressure- compression tendons comprises a sub-set of tendons comprising steering tendons that extend proximally to a proximal end of the rigidizing device and are configured for steering the distal region of the elongate flexible inner support tube.

10. The rigidizing device of claim 1, wherein the lengths of pressure-compression tendons are radially spaced apart from each other along the proximal to distal length of the elongate flexible inner support tube.

11. The rigidizing device of claim 1, wherein the support layer comprises an inner coil- wound tube.

12. The rigidizing device of claim 1, wherein the support layer comprises an outer coil- wound tube.

13. The rigidizing device of claim 1, wherein the compression layer is configured to receive positive pressure to rigidize the elongate body.

14. The rigidizing device of claim 1, wherein the compression layer is configured to receive a negative pressure rigidize the elongate body.

15. The rigidizing device of claim 1, wherein the lengths of pressure-compression tendons are each held within a guide channel and / or tube extending along the long axis of the elongate body.

16. The rigidizing device of claim 1, wherein the lengths of pressure-compression tendons are unattached at their proximal and distal ends.

17. The rigidizing device of claim 1, wherein the pressure-compression tendons extend into the proximal region.

18. The rigidizing device of claim 1, wherein the plurality of lengths of pressure- compression tendons comprises between 4 and 25 lengths of pressure-compression tendons. - 58 - SG Docket No.: 13668-727.60019. The rigidizing device of claim 1, wherein the plurality of lengths of pressure- compression tendons are formed of a single loop of material.

20. The rigidizing device of claim 1, wherein the plurality of lengths of pressure- compression tendons extend proximally at least partially through the proximal region.

21. A method, the method comprising: steering a rigidizing device so that the rigidizing device bends while in a flexible configuration, wherein the rigidizing device comprises an elongate body extending proximally to distally in a long axis, a plurality of lengths of pressure-compression tendons that extend lengthwise parallel to the long axis in a distal region of the elongate body, and a rigidizing layer extending in a proximal region of the elongate body, wherein the rigidizing layer comprises a plurality of filament lengths crossing over each other; and applying pressure so that a compression layer within the elongate body prevent or limits axial movement of the lengths of pressure-compression tendons and so that the compression layer prevents the plurality of strand lengths from sliding over each other to convert the rigidizing device to a rigid configuration; and releasing the pressure to convert the rigidizing device to the flexible configuration.

22. The method of claim 21, further comprising steering the distal end region using one or more of the lengths of pressure-compression tendons to steer the distal end region.

23. The method of claim 22, wherein steering comprises copying the shape of an elongate device within a lumen of the rigidizing device.

24. The method of claim 21, further comprising inserting the device into a lumen of a patient’s body.

25. The method of claim 21, wherein applying pressure comprises applying a positive pressure.

26. The method of claim 21, wherein applying pressure comprises applying a negative pressure.

27. A rigidizing apparatus comprising: an elongate body extending in a proximal to distal long axis; - 59 - SG Docket No.: 13668-727.600a plurality of lengths of pressure-compression tendons extending in the long axis within a distal region of the elongate body that are configured to slide axially relative to the elongate body in a flexible configuration; a rigidizing layer extending in a proximal region of the elongate body comprising a plurality of strand lengths configured to slide over each other in a flexible configuration; and a compression layer configured to rigidize the first rigidizing device by preventing the pressure-compression tendons from sliding axially and the plurality of strand lengths from sliding over each when pressure is applied against the compression layer.

28. The apparatus of claim 27, configured to form a nested system of rigidizing devices, the apparatus further comprising a second rigidizing device configured to rigidize, wherein the second rigidizing device is nested with the first rigidizing device, and wherein the rigidizing devices are configured to translate relative to one another and to rigidize to propagate a shape along the nested system.

29. The apparatus of claim 27, wherein the rigidizing layer extending over the elongate flexible tube within the proximal region comprises a plurality of filament lengths crossing over and under each other and configured shear relative to each other in the flexible state.

30. The apparatus of claim 27, wherein at least some of the lengths of pressure- compression tendons extend proximally to a proximal end of the rigidizing device and are configured for steering the distal end of the elongate flexible tube.

31. The apparatus of claim 27, wherein at least some of the lengths of pressure- compression tendons are either unattached at their proximal end or form a loop connecting two of the length of pressure-compression tendons.

32. The apparatus of claim 31, wherein the plurality of lengths of pressure-compression tendons comprises a steering sub-set of tendons extend proximally to a proximal end of the rigidizing device and are configured for steering the distal end of the elongate flexible tube, and further wherein the plurality of lengths of pressure-compression tendons comprises a non-steering subset of tendons that are either unattached at their proximal end or that form a loop connecting two of the length of pressure- compression tendons. - 60 - SG Docket No.: 13668-727.60033. The apparatus of claim 27, wherein the lengths of pressure-compression tendons are held in radially spaced apart positions along the proximal to distal length of the elongate flexible inner support tube.

34. The apparatus of claim 27, further comprising an inner coil-wound tube.

35. The apparatus of claim 27, wherein the compression layer comprises a bladder configured to apply a positive pressure.

36. The apparatus of claim 27, wherein the compression layer is configured to apply a negative pressure to compress the plurality of lengths of pressure-compression tendons against the elongate flexible tube.

37. The apparatus of claim 27, wherein the lengths of pressure-compression tendons are within a plurality of guides / tubes along the length that are open periodically to expose the tendon.

38. The apparatus of claim 27, wherein the lengths of pressure-compression tendons are capped at their proximal ends.

39. The apparatus of claim 27, wherein the lengths of pressure-compression tendons are secured to the elongate flexible tube by a material having a durometer of 60A or less on the Shore A scale.

40. The apparatus of claim 27, wherein the plurality of lengths of pressure-compression tendons comprises between 4 and 24 lengths of pressure-compression tendons. - 61 - SG Docket No.: 13668-727.600

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