Dynamic stiffening method and apparatus

Abstract

Described herein are rigidizable apparatus (e.g., devices, systems, etc.) whose transition between rigid and flexible configurations can be controlled, for example, by the application of positive and / or negative pressure. These apparatus can be configured to transition between a highly flexible configuration, in which the elongated device can be flexible or pliable, and a highly rigid (or selectively rigid) configuration, which is many times stiffer than the flexible configuration.

Description

[Technical Field]

[0001] Priority claims

[0001] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 394,570, entitled "DYNAMIC RIGIDIZATION METHODS AND APPARATUSES," filed August 2, 2022, the entire contents of which are incorporated herein by reference.

[0002] Incorporation by Reference

[0002] All publications and patent applications mentioned in this specification are incorporated herein by reference in their entirety, as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. [Background technology]

[0003] Surgical devices can include elongated, sometimes tubular, structures, including catheters, sheaths, scopes (e.g., endoscopes), wires, overtubes, cannulas, trocars, or laparoscopic instruments. These devices can function as separate add-on devices or can be integrated into the main body of the device. The devices are inserted into the body to access areas therein, sometimes forming passageways for additional diagnostic and therapeutic medical devices. In some cases, it is beneficial for such elongated medical devices to be rigid or flexible, and in many cases, it would be particularly beneficial for these devices to be modified from a flexible to a rigid configuration. While highly flexible devices offer significant advantages, and rigid devices also offer significant advantages, each also has its drawbacks. 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 can be problematic when navigating tortuous passageways, relatively open areas, or body regions with passageways of variable (or large) tubular diameters, where reliable contact with the outer diameter of the tubing may be difficult. Furthermore, highly flexible tubes may buckle, prolapse, loop, or have problems supporting additional tools or devices. Stiff tubes are difficult to navigate within the body and may cause injury when forced through certain anatomical pathways.

[0004]

[0004] It would therefore be beneficial to provide a medical device that is selectively stiffenable and can controllably transition between highly flexible and highly rigid configurations. While such tools provide safe, efficient, and precise access to otherwise difficult-to-reach anatomical locations, it would be beneficial to make various improvements to stiffenable devices, including improvements that make the devices safer, provide a wider range of flexibility and stiffening, allow for thinner walls, increase manufacturability, and enable the ability to function as a higher performance composite system.

[0005]

[0005] Apparatus and methods that can address these needs are described herein. Summary of the Invention [Means for solving the problem]

[0006] Generally, described herein are rigidizable apparatus (e.g., devices, accessories, systems, etc.) that can control the transition between a rigid and a flexible configuration. This transition occurs by multiple means, such as application or release of positive and / or negative pressure, linkage with a cable, phase change material, magnetic material, electrostatic, or Nitinol actuation. In some examples, the apparatus may be configured to transition between a highly flexible configuration, in which the elongated device (e.g., catheter, tube, rod, etc.) may be flexible or pliable, and a highly rigid (or selectively rigid) configuration that is many times more rigid than the flexible configuration (e.g., 2x, 3x, 5x, 7x, 10x, 12x, 15x, 20x, 30x, 40x, 50x, 75x, 100x, etc.). Also described herein are nested sets of two or more devices, at least one or more of which may be rigidizable. These devices may be used to advance or retract the nested set along a tortuous path. By selectively stiffening and non-rigidifying the dual rigidizable device, the shape may be propagated through a tortuous path.

[0007] The stiffening devices described herein may include a stiffening layer or region that engages a compressive layer (which may be or include a bladder) that applies a force to the stiffening layer to stiffen or, in some cases, de-rigidify (e.g., release) the stiffening layer. In some examples, these stiffening devices may include a layer that includes braids, knits, wovens, cut pieces, randomly distributed or randomly oriented filaments or strands, engagements, links, flakes, plates, pieces, particles, granules, crossed filaments, or other materials that form the stiffening layer.

[0008] For example, described herein is a stiffening device that includes a braided material (e.g., a braided tube) as all or part of a stiffening layer. Such a device may include an elongated flexible tube, a stiffening layer that includes the braided structure, an inlet configured to attach to a pressure source, and a compression layer configured to be compressed against the stiffening layer by a pressure differential from the inlet, where the stiffening device is configured to change between a rigid state and a flexible state upon application or release of pressure.

[0009]

[0009] In any of these devices, the braided layer may be a braided tube. The braid, which may be equivalently referred to herein as a knit or braided material, may be formed from a single fiber or may be braided from multiple fibers. The fibers forming the braid may be yarn, filament, monofilament, multiple filaments, strand, wire, twist, etc. The fibers may be continuous, and each of the filament lengths forming the stiffening layer may be part of a single fiber or may be segmented into multiple filament lengths. For example, the braid may be a single fiber that is segmented / cut at regular or irregular lengths. The braid structure may be configured so that the grain direction of the braid structure extends along the longitudinal axis of the flexible tube. Alternatively, the braid structure may be configured so that the grain direction of the braid structure is perpendicular to the longitudinal axis of the flexible tube.

[0010] The knitting configuration may be modified to optimize the flexibility of these devices in the non-rigidified configuration and / or the stiffness in the rigidified configuration. For example, the knitting structure may have an average loop length that is two or more times (e.g., three, four, five, six, seven, eight, nine, ten, twenty, forty, sixty, eighty, eighty, one hundred or more times) the average loop width. As noted above, the knitting structure forming the stiffening layer may include braided fiber bundles, single filaments, bundles of filaments, etc. The material (e.g., filaments) forming the knitting structure may be any suitable material, such as yarns made from natural or artificial materials, metals, metal alloys, composite materials, polymeric materials, natural fibers, etc. In some cases, the braid is formed from fibers including, for example, aramid (Kevlar™, Twaron™, Technora™), Vectran™, UHMWPE (Dyneema™ or Spectra™), Zylon™, nylon, polyester, or carbon fiber. In some cases, the braid is formed from a composite of multiple materials. In some cases, the braid is formed from a metal or multiple metals including, for example, nitinol, stainless steel alloys, magnesium alloys, tantalum, cobalt chromium alloys, etc.

[0011] In any of the stiffening devices described herein, the outer layer may be a reinforced outer layer, including, but not limited to, a coil-reinforced layer. For example, the elongated flexible tube may include a coil-reinforced tube. Alternatively, the elongated flexible tube may include a non-coil-reinforced tube.

[0012] Any of these devices may include one or more inlets. For example, the device (e.g., a stiffening device) may include one or more inlets coupled to the proximal end of a flexible, elongated tube. The inlets may be coupled to a pressure source (e.g., positive pressure or vacuum / negative pressure) at the proximal end region to apply a pressure differential to stiffen or relax the device, making it more flexible or de-rigidify it. The inlets may be coupled to an input to the system at the distal end, including via a supply line. For example, the inlets may be configured to attach to a positive pressure source. In some examples, the compressible layer is configured to press against the stiffening layer when positive pressure is applied through the inlets. In some examples, the inlets may be configured to attach to a negative pressure source, and the compressible layer may be configured to press against the stiffening layer when negative pressure is applied through the inlets.

[0013] Any of the devices described herein may include a second (or more) inlet, e.g., a secondary inlet, which may be, for example, on the opposite side of the compressible layer from the first (primary) inlet. The secondary inlet may be passive (i.e., an air vent) or active (i.e., a vacuum inlet to remove mass (e.g., air or water) from within the volume to provide additional actuation force or to reduce or eliminate mass from potential inadvertent release within the body). This may enable, for example, a device to simultaneously apply both positive and negative pressure, e.g., with one force acting on both sides of the compressible layer, improving performance including, but not limited to, stiffening values ​​(e.g., stiffening / de-stiffening rate, applied pressure, etc.).

[0014] The compression layer may be any suitable layer for applying a force to the stiffening layer to stiffen it. In some examples, the compression layer is a bladder. The compression layer may be configured to conform to the stiffening layer. In some examples, the compression layer may be configured to not conform to the stiffening layer. For example, the compression layer may be configured to press against the stiffening layer but not significantly deform it. The compression layer may be configured to press against the stiffening layer and then deform and expand. In some examples, the compression layer comprises an elastomeric (e.g., stretchable) material. In some cases, the compression layer is not an elastomer. The compression layer may be a 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 stretchable material that is an oversized material (e.g., polyethylene terephthalate (PET), nylon, low-density polyethylene (LDPE), or plastomer). Any of these devices may include multiple distinct stiffening regions, for example, actuated individually or collectively along the length of the device.

[0015] Compressed layers may be formed by several methods. Many bladders are extruded as tubes. Sheets can be made (extrusion, solution casting, spraying, etc.) and then heat sealed or bonded into tubular structures. Tubes can be made, for example, by dipping a mandrel into an elastomer bath or a solvated elastomer bath. Layers may be made by spraying a film. In this case, the film begins as a bubble of material (typically plastic or plastomer, but sometimes elastomer), which has high-pressure air behind it and expands or stretches into a tube, which is then conveyed (usually vertically) as it cools while being diametrically restrained. This approach allows for leak-free quality control and allows for low-cost, thin structures to be made.

[0016]

[0016] The stiffening device may be configured to have a rigid configuration when positive or negative pressure is applied through the inlet, and a flexible configuration when no pressure is applied through the inlet.

[0017]

[0017] Examples of stiffenable devices including braided stiffenable members are described in more detail herein and offer numerous advantages over other stiffening members.

[0018] Also described herein are devices (e.g., rigidizable devices) having integrated compressible and stiffening layers. In some examples, the stiffening layer may include lengths of filaments (including, but not limited to, encapsulated) within a compressible material. Deforming the compressible material, for example, by applying positive and / or negative pressure, may transition the stiffening layer between a flexible and a rigid configuration.

[0019] For example, the stiffening device may include an elongated flexible tube, a stiffening layer including an array of filament lengths within a compressed material, the array of filament lengths configured to slide over one another when the compressed material is in a first configuration and configured to engage one another when the compressed material is in a second configuration, and an inlet configured to attach to a pressure source, the compressed material transitioning between the first and second configurations by applying a pressure differential from the inlet to change the stiffening layer between a rigid state and a flexible state. The first configuration may be an uncompressed configuration, and the second configuration may be a compressed configuration. The pressure source may be a positive pressure source or a negative pressure source (e.g., a vacuum).

[0020] The array of filament lengths may comprise an array of filaments. For example, the array of filament lengths may be portions of a single filament or may be multiple lengths. In some examples, the filament lengths may be portions of a single filament, a bundle of filaments, etc. As noted above, the filaments may be wires, yarns, etc., and the filament material may be any suitable material, including metals, metal alloys, polymeric materials, natural fibers, etc. The filaments may be any suitable length. In some examples, the lengths of the filaments may vary and / or be of different lengths, and the filament crossing pattern may be consistently ordered or more random. For example, the material may be chopped filaments or stainless steel "wool."

[0021] In any of these examples, the array of filament lengths may be slidably enclosed within the compressible material in the first configuration. Thus, rather than being a layer above or below the stiffening layer, the compressible material may surround and / or encapsulate the strands of stiffening material. For example, the compressible material may include an elastomeric material. The filament lengths may be fully enclosed or may be configured to be held within channels or cavities in the elastomeric material, and the stiffening layer may become stiff as the material deforms, e.g., by applying positive or negative pressure. Generally, the compressible material may be any suitable compressible material. In some examples, the compressible material may be a lubricious material and / or the lubricious material may be within a channel or chamber that holds the stiffening layer. In some examples, the compressible material forms a bladder.

[0022] In any of these devices, the inlet may be configured to couple a pressure source to the gap between the elongated flexible tube and the stiffening layer. The elongated flexible tube may be the inner and / or outer tube of the device. Alternatively or additionally, the inlet may be configured to couple a pressure source to the enclosed region between the enclosed filament length and the compressed material.

[0023]

[0023] The elongated flexible tube may include an inner tube. In any of these examples, the device may include a reinforced outer layer, such as a coil-reinforced outer layer. The elongated flexible tube may include a coil-reinforced tube. The stiffening device may be configured to have a rigid configuration when positive or negative pressure is applied through the inlet and a flexible configuration when no pressure is applied through the inlet. Alternatively, the stiffening layer may be configured to be non-rigidified in a first configuration when there is no pressure differential between the inlet and the atmosphere.

[0024]

[0024] For example, the stiffening device described herein includes an elongated flexible tube and a stiffening layer including an array of filament lengths within a bladder, the array of filament lengths configured to move relative to each other when the bladder is in a flexible configuration, and the array of filament lengths configured to move less relative to each other when the stiffening layer is pressurized against the elongated flexible tube to a more stiffened configuration.

[0025]

[0025] The devices described herein also have a stiffening layer formed of multiple lengths of fiber that cross over and under each other and are configured to stiffen when positive pressure is applied. Because the filament lengths cross over and under each other, the application of positive pressure is particularly effective, allowing for a graded response to positive pressure, such that the greater the positive pressure, the stiffer the device can become.

[0026] For example, the stiffening device may include an elongated flexible tube, a stiffening layer including an array of filament lengths configured to cross over and under each other and move relative to each other, an inlet configured to attach to a positive pressure source, and a compression layer configured to be pressed against the stiffening layer by a pressure differential from the inlet to stiffen the stiffening layer, the stiffening device configured to change between a rigid state and a flexible state with the application or release of pressure. Moving relative to each other may include multiple types, directions, and modes of motion, including sliding, pivoting, shearing, displacement, etc.

[0027] As used herein, multiple filament lengths may be part of a single strand or may be individual strands of filaments. The filament lengths may be the same size or different sizes. For example, an array of filament lengths may include multiple discrete filaments. The stiffening layer may be a tube or other shape formed of a single fiber or multiple fibers (including single fibers that are broken / cut at regular or irregular lengths). At least some of the filament lengths in an array of filament lengths may be part of the same filament.

[0028]

[0028] Generally, the compressive layers described herein include, but are not limited to, structural layers that are sheets of material that apply a compressive force to the bladder layer and / or stiffening layer to stiffen or, in some cases, release the stiffening layer from stiffening. For example, the array of filament lengths may comprise a woven, braided, or knitted tube. The filaments may be in cut pieces and / or sewn.

[0029] The array of filament lengths may include one or more wires. As noted above, the filament lengths may be formed of any suitable material, such as a single filament, a bundle of filaments, e.g., a yarn, a metal, a metal alloy, a composite material, a polymeric material, a natural fiber, or the like.

[0030] Any of these devices may include a reinforced inner layer and / or outer layer, including a coil reinforcement layer. In any of these examples, the outer layer is not a coil reinforcement layer, as other outer layers may be used. In some examples, the elongated flexible tube includes a coil reinforced tube. The elongated flexible tube may include a tube that is not coil reinforced. The elongated flexible tube may include a laser-cut tube. The elongated flexible tube may include a series of connectors. An inlet may be coupled to a proximal end of the flexible elongated tube. The inlet may be configured to attach to a positive pressure source, and further, the compressible layer is configured to compress against the stiffening layer when positive pressure is applied through the inlet. The inlet may be configured to attach to a negative pressure source, and further, the compressible layer is configured to compress against the stiffening layer when negative pressure is applied through the inlet. In some examples, the compressible layer includes an elastomeric layer. In some examples, the compressible layer includes a bladder, or multiple bladders, for example, for multiple stiffening regions. In any of the devices described herein, the bladder may or may not be elastomeric. For example, the bladder may be plastic, plastomer, or composite. The stiffening devices described herein may be configured to have a rigid configuration when positive or negative pressure is applied through an inlet and a flexible configuration when no pressure is applied through the inlet.

[0031] Also described herein are pressure-actuated devices, including high pressure. In some examples, the greater the applied pressure, the stiffer the device. For example, described herein are positive pressure (e.g., high pressure) devices in which a compressible member (e.g., a bladder) deforms, expands, and engages with wires to form a stiffening layer. The stiffening device may include a flexible inner tube fabricated or reinforced to withstand radial compressive loads, a flexible outer tube reinforced to withstand radial tensile loads, a plurality of filament lengths configured to cross over and under each other and move relative to each other, a stiffening layer between the inner and outer tubes, and a compression layer configured to deform onto or into the stiffening layer when positive pressure is applied to the compression layer, such that application of pressure limits (or in some examples reduces) movement of the plurality of filament lengths, thereby increasing stiffness. For example, when the positive pressure device is pressurized, the positive pressure on the inner tube may reduce the diameter of the inner tube and / or may structurally collapse the inner tube, such that it radially or otherwise collapses. The device is configured to withstand these failures within normal operating pressures. When the positive pressure device is pressurized, the outer tube applies positive pressure as an expansion or tensile load to the stiffening wire, nominally expanding its diameter and potentially breaking the stiffening element if the stiffener is too small. The device is configured to withstand these failures within normal operating pressures.

[0032]

[0032] As described above, the deformable compressible layer may include a bladder. The stiffening layer may be between the flexible outer tube and the compressible layer, the compressible layer being configured to compress the stiffening layer into the outer tube when a positive pressure is applied to the compressible layer. The stiffening layer may be between the flexible inner tube and the compressible layer, the compressible layer being configured to compress the stiffening layer into the inner tube when a positive pressure is applied to the compressible layer. In some examples, the deformable compressible layer includes an elastomeric layer.

[0033] The flexible outer tube may be reinforced (e.g., spirally reinforced, braided, coiled, etc.) and may include embedded members and / or layers. Alternatively or additionally, the flexible inner tube may include a reinforcement layer. The array of filament lengths may include multiple filaments. These filament lengths may be formed of a single fiber or multiple fibers (including formed from a single fiber that is broken / cut at regular or irregular lengths). In some examples, the array of filament lengths includes a weave, braid, or knit. The filament lengths may be ordered or unordered. The array of filament lengths may include one or more wires. For example, the array of filament lengths can be made of a single filament, a bundle of filaments, e.g., a yarn, a metal, a metal alloy, a polymeric material, a natural fiber, etc.

[0034] Any of these apparatuses (e.g., devices) may include one or more inlets in fluid communication with the compressible layer and configured to couple to a positive pressure source. Different inlets can control the application of pressure differentials (e.g., positive and / or negative pressure) to different regions of the apparatus, selectively stiffening different regions of the apparatus. The inlets may be coupled to either end (proximal or distal) of the flexible, elongated tube, or at an intermediate location.

[0035] The stiffening devices described herein may be configured to have a rigid configuration when positive pressure is applied through an inlet and a flexible configuration when no pressure is applied through the inlet. Alternatively, in some examples, the stiffening devices described herein may be configured to have a non-rigidified (flexible) configuration when positive pressure is applied through an inlet and a rigid configuration when no pressure is applied through the inlet.

[0036]

[0036] The devices described herein may include one or more stiffening layers that are actuated by the application of positive pressure, including high pressure. In particular, described herein are stiffening devices having a stiffening layer formed from a plurality of particles or granules that move in a loose configuration in a flexible configuration (e.g., in the absence of a pressure differential relative to the atmosphere) but become rigid when positive pressure is applied, for example, via a compression layer. When positive pressure is applied, the stiffening layer may harden or compress, thereby reducing the flexibility of the device or making it rigid. For example, the stiffening device may include a flexible inner tube, a flexible outer tube, a stiffening layer including a plurality of granules between the inner and outer tubes, an inlet configured to attach to a positive pressure source, and a compression layer between the inner and outer tubes configured to press against the stiffening layer when positive pressure is applied through the inlet to compress and stiffen the stiffening layer.

[0037] The granules may be of any suitable size or size distribution (e.g., 1 mm or less in diameter, 0.8 mm or less in diameter, 0.7 mm or less in diameter, 0.6 mm or less in diameter, 0.5 mm or less in diameter, 0.4 mm or less in diameter, 0.3 mm or less in diameter, 0.2 mm or less in diameter, 0.1 mm or less in diameter, 0.05 mm or less in diameter, 0.01 mm or less in diameter, etc.). The granules may be of any suitable material, typically a rigid or semi-rigid material (e.g., a polymer, a metal, a mineral, a composite material, etc.). The granules may be formed of a biocompatible material. In some cases, the granules may be bioabsorbable. The granules may be crystalline. The granules may have any suitable shape. For example, the granules may be round, square, faceted, elongated, oval, rectangular, obtuse, etc. In some examples, the shape of the granules may be regular. In some examples, the shape of the granules may be irregular. The granules may include both regular and irregular shapes and may include a variety of different shapes and / or sizes in the same rigidizing layer. The granules may be enclosed inside an enclosure, such as a packet formed into a cylindrical shape. The packet may be sealed or porous (e.g., may include pores smaller than the granules). In some examples, the compression layer may contain or partially contain the granules. The compression layer may actuate, urge, push, or solidify the rigidizing layer. For example, the compression layer may be an enclosure or part of an enclosure. The compression layer may be a bladder. The compression layer may be an elastomeric layer.

[0038] As in any of the examples described herein, the outer and / or inner tube may be reinforced or unreinforced. It may be a laser-cut tube. The laser-cut tube may be integrated with a distal bend that has a different cut pattern but is part of the same tube. In a reinforced version, for example, the inner and / or outer tube may include a coil reinforcement, such as a material exhibiting high tensile strength. This may be wire, polymer, composite fiber, thread made of natural or artificial materials, metal, metal alloy, composite material, polymeric material, natural fiber, etc. In some cases, it may be a fiber including, for example, aramid (Kevlar™, Twaron™, Technora™), Vectran™, UHMWPE (Dyneema™ or Spectra™), Zylon™, nylon, polyester, polyethylene, Dacron, polypropylene, fiberglass, basalt, or carbon fiber. In some cases, it may be formed of a composite of multiple materials. For example, it may be formed from metals including nitinol, stainless steel alloys, magnesium alloys, tantalum, cobalt-chromium alloys, and the like.

[0039] Any device that includes granules as part of the stiffening layer may be configured to change between a rigid and a flexible state by application or release of pressure. Thus, application of positive pressure may, in some instances, compress the granules without the need to apply a vacuum by driving a compression layer against the granules and the inner and / or outer tube to stiffen the granules.

[0040] Also described herein are apparatus (e.g., devices) and methods in which the stiffening layer includes multiple members (e.g., layers, strips, sections, or sublayers, such as arms, scales, plates, etc.). Application of pressure (e.g., positive pressure) may drive the multiple sublayers (e.g., arms, plates, scales, etc.) against the inner tube (or outer tube in some configurations) and / or adjacent sublayers, with increasing pressure causing the device to become more rigid. Application of such positive pressure may deliver stiffening forces significantly greater than those deliverable by a pressure differential from standard atmospheric pressure to a vacuum. Alternatively, in some configurations, the device may be configured such that the sublayers are biased toward one another in an unactuated state (when no pressure is applied), and application of positive pressure causes the sublayers to separate from the inner or outer tube and / or from each other, transitioning the device from a rigid state to a flexible state.

[0041]

[0041] For example, the stiffening device described in this specification includes a flexible outer tube, a flexible inner tube, a stiffening layer including a plurality of overlapping members between the inner tube and the outer tube, an inlet configured to be attached to a positive pressure source, and a compression layer between the outer tube and the inner tube configured to be pressed against the stiffening layer when positive pressure is applied through the inlet to compress and stiffen the stiffening layer.

[0042] The overlapping member may include multiple overlapping sublayers (e.g., scales or plates). In some examples, the overlapping member includes multiple arms extending from one or more radial attachment portions, which may extend along the length of the device and the multiple arms may extend either proximally and / or distally from the radial attachment portions. The radial attachment portions may be partial or complete rings. In some examples, the overlapping member is disposed radially and longitudinally between the inner tube and the outer tube. Any number of overlapping sublayers (e.g., arms, scales, plates, etc.) may overlap each other. For example, the overlapping member may include two or more layers of overlapping members. The overlapping members may interlock with each other. For example, in some examples, the multiple overlapping members interlock along the length of the stiffening layer. In the flexible configuration, the multiple overlapping members may be configured to slide over each other, while in the rigid configuration, the multiple overlapping members may be inhibited from sliding over each other. For example, in some cases, the multiple overlapping members may each include one or more engagement features between the overlapping members.

[0043] Any suitable compression layer may be used. As noted above, in some examples, the compression layer includes a bladder. The compression layer may be an elastomeric layer or a non-elastomeric layer. The outer tube and / or inner tube may be reinforced. For example, the flexible inner tube and / or outer tube may include a coil reinforcement layer. In any of these examples, the inlet may be coupled to the proximal end of the flexible elongate tube.

[0044] The stiffening device may be configured to change between a rigid state and a flexible state upon application or release of pressure (eg, positive pressure).

[0045] In some examples, the stiffening device includes a stiffening layer with overlapping sublayers (e.g., arms, scales, plates, etc.) in either a statically or dynamically positioned configuration; in some examples, the sublayers do not overlap in either a statically or dynamically positioned configuration. The sublayers may instead be adjacent to one another (e.g., overlapping or non-overlapping) radially and along the length of the device. For example, the stiffening device may include a flexible outer tube, a flexible inner tube, a stiffening layer including a plurality of abutting members disposed radially and longitudinally adjacent to one another between the inner and outer tubes, an inlet configured to attach to a positive pressure source, and a compression layer between the outer and inner tubes configured to press against the stiffening layer when positive pressure is applied through the inlet to compress and stiffen the stiffening layer. In some examples, the layers may be positioned by spiral wrapping. The layers may be positioned by attaching the scales to a central “spine” (e.g., a wire or a substrate connecting the scales). The spine may be attached at one end and slide at the other end as the structure is bent or articulated, thereby changing the length of the inner or outer passageway.

[0046]

[0046] These layers may be positioned by being attached to the center of the base structure or superstructure so that they are in a relatively fixed position, but may have portions shaped to slide over other adjacent elements, so that their relative positions are fixed as pressure is applied to solidify the layers together.

[0047] For example, the abutment members may include multiple arms extending from one or more radial attachment portions. The abutment members may be configured so that they do not overlap (e.g., the abutment members do not overlap) or so that they only overlap when the device is bent beyond a predetermined angle.

[0048] The overlapping members may include two or more rings of adjacent members radially disposed around the device and / or may include two or more rows of adjacent members.

[0049] As discussed above, the compressible layer may include an elastomeric or non-elastomeric material. In some examples, the compressible layer includes a bladder. The outer tube and / or inner tube may be reinforced. Any of these devices may include one or more inlets. Any of these devices may include a stiffening device configured to change between a rigid state and a flexible state upon application or release of pressure.

[0050] Also described herein are stiffening devices including a plurality of interlocking geometries that engage with each other to stiffen the device when positive pressure is applied (e.g., to a compression layer). For example, a stiffening device described herein includes a flexible outer tube, a flexible inner tube, a stiffening layer including a plurality of radial engagement members between the inner and outer tubes, an inlet configured to attach to a positive pressure source, and a compression layer between the outer and inner tubes configured to be pressed against the stiffening layer when positive pressure is applied through the inlet to drive engagement of the radial engagement members.

[0051] The plurality of radial engagement members may include interlocking members. For example, the plurality of radial engagement members may include a plurality of radially nested members extending along a length from proximal to distal. The plurality of radial engagement members may include a plurality of radially flexible members.

[0052] In some examples, the stiffening layer may be configured as a woven set. For example, a stiffening device described herein includes a flexible outer tube, a flexible inner tube, a stiffening layer including a woven layer between the inner and outer tubes, an inlet configured to attach to a positive pressure source, and a compression layer between the outer and inner tubes configured to press against the stiffening layer when positive pressure is applied through the inlet to compress and stiffen the stiffening layer. The woven layer may include multiple filament lengths configured to cross over and under each other and shear relative to each other. The compression layer may be configured to contact the flexible outer or inner layer and conform around the multiple filament lengths to prevent the multiple filament lengths from shearing relative to each other when positive pressure is applied through the inlet. The multiple filament lengths may be separate (e.g., discrete filament lengths that are not part of the same strand or strands of filament). For example, the multiple filament lengths may be broken or cut into a network of separate strands or sections. This allows for increased flexibility while also allowing for stiffening as the individual strands overlap one another. The individual strands may be of any suitable length or range of lengths. For example, the individual strands may have a length less than the diameter of the tube (e.g., 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, etc., of the diameter of the flexible inner tube, or between about 5% and 90%, between about 10% and 80%, between about 10% and 70%, etc.). The individual strands may have a length greater than the length of the tube (e.g., 1.5 times, 2 times, 4 times, 6 times, 8 times, 10 times, 20 times, 40 times, 100 times, etc.).

[0053] Any of the devices described herein may be coupled together to form a nested system configured to coordinate movement (e.g., advancement and retraction) and stiffening to enable movement through tortuous regions of the anatomy. Generally, any of the devices described herein are maneuverable. For example, any of these devices may have a maneuverable distal end. For example, in any of these devices, the distal end region may include one or more linkages. These linkages may be actuated in a number of ways, including by cable, motor, hydraulics, pneumatics, shape memory materials, or electroactive polymers (EAPs). The linkages may have one or more wires extending proximally from the distal end region to enable manipulation of the distal end region. The distal end region may be distal to the stiffening region or may be part of a stiffening system. The distal end region may have the same stiffening elements as the main stiffening system or may have different stiffening elements in this distal region. Generally, all or a majority of the length of the elongate body of the device may be stiffenable. In other embodiments, only a portion of the length of the elongate body may be stiffenable.

[0054] For example, a nested system may include a first stiffening device including multiple layers, the first stiffening device configured to be stiffened by applying a pressure differential to drive a compressible layer relative to a stiffening layer forming at least one of the multiple layers of the first stiffening device, and a second stiffening device configured to stiffen, the second stiffening device nested with the first stiffening device, the first and second stiffening devices configured to alternately stiffen to translate relative to each other to propagate a shape. The second stiffening device may be internal to the first stiffening device or external to the first stiffening device.

[0055] The first stiffening device and the second stiffening device may be the same type of stiffening device (e.g., each may include a knitted stiffening member, etc.) or may be different types of stiffening devices (e.g., the outer stiffening device may include a knitted stiffening layer, the inner stiffening device may include a woven stiffening layer, etc.). The second stiffening device may be actuated by a range of methods, including methods that do not include the application or removal of positive or negative pressure.

[0056]

[0056] Generally, any of the devices described herein may be configured, for example, as a tube including a central lumen or multiple lumens (e.g., within a radially flexible inner tube), or as a rod (e.g., without an accessible lumen). In particular, the nested systems described herein may include an outer (e.g., mother) device configured as a stiffening tube and an inner (e.g., child or daughter) device configured as a stiffening tube or stiffening rod. If a stiffening rod, the inner diameter (ID) may be used for payload (e.g., components inside the scope, such as electrical cables, operating cables, pressure lines, irrigation lines, and working channels). In another embodiment, all or a portion of the payload (e.g., cables, lines) may be located outside the inner diameter. Alternatively, it may be a stiffening device without an inner coiled tube, for example, a device in which a compression layer forms the inner diameter of the device.

[0057] The first and second stiffening devices may each include continuously curved surfaces configured to slide smoothly relative to one another. For example, the outer surface of the inner (e.g., child) device may be configured to be smooth and lubricious, and the inner surface of the outer (e.g., mother) device may be smooth and lubricious. Both of these devices may be configured to avoid or prevent wrinkling of the surfaces they slide against (e.g., the inner surface of the outer device and / or the outer surface of the inner device) even when applying pressure and / or bending to stiffen or release the devices from stiffening.

[0058]

[0058] For example, the first stiffening device and the second stiffening device may each include a pressurized coiled tube configured to form a continuous curved surface for sliding smoothly against each other in both the stiffened and non-rigidified configurations.

[0059] The compressive layer (e.g., the compressive layer of the first stiffening device and / or both stiffening devices) may include a bladder. The stiffening layer may include multiple filament lengths configured to cross over and under each other and shear relative to each other. In some examples, the stiffening layer may include a braided layer, a knitted layer, a woven layer, or the like (any of the stiffening layers described herein). As described above, at least one of the first stiffening device and the second stiffening device may include a maneuverable or articulated distal end region including multiple links. These may be various types of links, including laser-cut tubing elements, discrete links, or tubing with a high tendency to bend. At least the first stiffening device is configured to be stiffened by applying either positive or negative pressure. In some examples, the second stiffening device is configured to nest within the first stiffening device (or alternatively, the first stiffening device is configured to nest within the second stiffening device). Any of these apparatuses may include a controller and actuator configured to coordinate and manipulate the alternating stiffening and movement of the first stiffening device and the second stiffening device.

[0060] Any of the nested systems described herein may include a stiffenable device including a knit as a stiffening layer. For example, a nested system described herein may include a first stiffening device including multiple layers, the first stiffening device configured to be stiffened by applying a pressure differential to drive a compressible layer relative to a knitted stiffening layer forming at least one of the multiple layers of the first stiffening device, and a second stiffening device configured to stiffen, the second stiffening device nested with the first stiffening device, wherein the first and second stiffening devices are configured to stiffen to translate relative to each other to propagate a shape along the nested system.

[0061] As described above, the braided stiffening layer may comprise a braided tube. In some examples, the braided stiffening layer is configured such that the wale direction of the braid extends along the longitudinal axis of the flexible tube. Alternatively, the braided stiffening layer may be configured such that the wale direction of the braid is perpendicular to (or at an angle with) the longitudinal axis of the flexible tube. The braided stiffening layer may comprise an average loop length greater than two times the average loop width. The braided stiffening layer may comprise a braided fiber bundle.

[0062] In any of these examples, the first stiffening device and the second stiffening device may each include a continuous curved surface configured to slide smoothly relative to one another. The first stiffening device and the second stiffening device may each include a pressurized coiled tube configured to form a continuous curved surface to slide smoothly relative to one another. As described above, the compressible layer may include a bladder. At least one of the first stiffening device and the second stiffening device may include an operable distal end region including multiple links; for example, the second stiffening device may include an operable distal end region including multiple links actuated by one or more actuation methods (including wires or tendons extending the length of the device). Alternatively or additionally, the distal end region may be operable by hydraulics (including one or more motors at the distal end, hydraulics, etc.), such as one or more motors at the distal end region.

[0063]

[0063] The first stiffening device may be configured to be stiffened by application of positive pressure, and the second stiffening device may be configured to nest within the first stiffening device.

[0064] Any of these nested apparatuses may include a controller configured to regulate the alternating stiffening of the first stiffening device and the second stiffening device.

[0065] Any of these nested devices may include one or more actuators configured to operate devices driven by signals from a user input device in conjunction with signals from a controller.

[0066] Any of the apparatuses described herein may include magnetically and / or electrostatically actuated stiffening devices. For example, a nested system described herein may include a first magnetic stiffening device configured to be stiffened by applying a magnetic and / or electric field, and a second stiffening device configured to stiffen, the first stiffening device and the nested second stiffening device configured to translate relative to each other and alternately stiffen to propagate a shape along the nested system. The first magnetic stiffening device may include a magnetorheological material. Alternatively, the first magnetic stiffening device may include an electrorheological material.

[0067] As described above, the first stiffening device and the second stiffening device may each include a continuous curved surface configured to slide smoothly relative to one another in both the stiffened and non-stiffened configurations. The second stiffening device may be configured to nest within the first stiffening device, or the first stiffening device may be configured to nest within the second stiffening device. Either of these apparatuses may include a controller configured to coordinate the alternating stiffening of the first and second stiffening devices.

[0068] Any of the devices described herein may be configured so that either or both of the inner and outer tubes (e.g., inner elongated tube, outer elongated tube) that form the rigidizable device are reinforced by including one or more coils (e.g., helically wound coils) that provide radial stiffness and strength without significantly reducing bending flexibility.

[0069] Additionally, any of the devices described herein may be configured such that the inner and / or outer tubes have different softness (e.g., durometer) on the inner surface compared to the outer surface. The outer surface of the device may be affected by other devices or anatomical structures. Therefore, resistance to punctures or abrasions at this surface is critical. The inner surface may be the surface against which the stiffening layer presses or reacts. At this location, appropriate softness is important to enhance flexibility and create a surface against which the stiffening layer presses. Modulating the hardness effectively helps to modulate the degree to which the stiffening layer embeds or distorts under pressure, thereby becoming a primary driver of stiffening value. Surprisingly, the inventors have discovered that by modulating the material and its durometer at each designated location, the different needs of the different layers can be optimized. For example, results may be further optimized by making the outer layer from a high-durometer material, including for greater abrasion or puncture resistance, and the inner layer of the tube from a low-durometer material, including for maximizing the stiffening range. In any of these devices, the outer tube may be configured so that the exterior or outer layer of the tube is scratch resistant while the interior or inner surface is softer (e.g., has a lower durometer), which may be used with or without internal reinforcement.

[0070] For example, an elongated stiffening device may include an inner elongated tube, an outer elongated tube including an inner region, a reinforcing member (e.g., a radial reinforcing member), and an outer region, the inner region having a durometer hardness lower than that of the outer region, a stiffening layer, an inlet configured to provide positive pressure between the inner elongated tube and the outer elongated tube, and a compressible layer configured to compress the stiffening layer against the outer elongated tube when positive pressure is applied through the inlet, the stiffening device configured to change between a rigid state and a flexible state upon application or release of positive pressure. The outer region may be an outer surface of the device, and the inner region may be an inner surface of the outer tube, against which the stiffening layer and / or compressible layer may contact. The outer region may have a durometer hardness of between about 70A on the Shore A scale and 80D on the Shore D scale. The inner region may have a durometer hardness of between about 30A and about 90A on the Shore A scale.

[0071] The reinforcing member may include a wound coil (e.g., wire, ribbon, filament, etc.). The reinforcing member may be helically wound around the tube and may in some instances be referred to as a radial reinforcing member. The wound coil may be between the inner region and the outer region. The coil may be single or multiple. In some instances, the wound coil is laminated between the inner region and the outer region. The compression layer may be configured to compress the stiffening layer against the inner layer of the outer elongate tube when positive pressure is applied through the inlet.

[0072] The stiffening layer may correspond to any of those described above. For example, the stiffening layer may include a plurality of filament lengths configured to cross over and under each other and shear relative to each other. The compressive layer may include an elastomeric layer and / or may be or be configured as a bladder.

[0073] In any of these devices, the inner tube of the rigidizable device may be configured to have a different durometer hardness on the outer region of the tube compared to the inner region of the tube. For example, an elongated stiffening device may include an outer elongated tube, an inner elongated tube including an inner region, a reinforcing member, and an outer region, the outer region having a durometer hardness higher than that of the inner region, a stiffening layer, an inlet configured to provide positive pressure between the inner elongated tube and the outer elongated tube, and a compressible layer configured to compress the stiffening layer against the inner elongated tube when positive pressure is applied through the inlet, the stiffening device configured to change between a rigid state and a flexible state upon application or release of positive pressure. For example, the outer region may have a durometer hardness of between about 70 A on the Shore A scale and about 80 Shore D on the Shore D scale. The inner region may have a durometer hardness of between about 30 A on the Shore A scale and about 90 Shore A.

[0074] In some examples, the elongated stiffening device includes an outer elongated tube, an inner elongated tube including an inner region, a reinforcing member, and an outer region, the outer region having a durometer hardness greater than that of the inner region, a stiffening layer, an inlet configured to provide negative pressure between the inner elongated tube and the outer elongated tube, and an outer tube configured to press the stiffening layer against the inner elongated tube when negative pressure is applied through the inlet, the stiffening device configured to change between a rigid state and a flexible state upon application or release of negative pressure. For example, the inner region may have a durometer hardness of between about 30 A and about 90 A on the Shore A scale, and / or the outer region may have a durometer hardness of between about 70 A and about 80 Shore D on the Shore D scale. The reinforcing member may include a wound coil. The wound coil may be between the inner region and the outer region (or, in some examples, laminated between the inner region and the outer region). The compression layer may be configured to compress the stiffening layer against the outer elongate tube when positive pressure is applied through the inlet.

[0075] As noted above, any of the stiffening layers may be used in these devices, including stiffening layers comprising a plurality of filament lengths configured to cross over and under each other and shear relative to each other. Compression layers may include elastomeric or non-elastomeric layers, and in some instances are configured as bladders.

[0076]

[0076] Any of these devices may include a torsional stiffening layer. In particular, the high pressure devices described herein may include a torsional stiffening layer. For example, the stiffening device may include a flexible inner tube configured to provide torsional stiffening, the flexible inner tube including a first coil wire and a torsional braid, a flexible outer tube, a stiffening layer between the inner and outer tubes, an inlet configured to attach to a positive pressure source, and a compression layer configured to compress against the stiffening layer when positive pressure is applied through the inlet, the stiffening device configured to have a rigid configuration when positive pressure is applied through the inlet and a flexible configuration when positive pressure is not applied through the inlet.

[0077] The first coil wire may comprise a single or multiple flat wires helically wound as part of the flexible inner tube. The wires may be wound in the same or opposite directions. The wires may be separate wires or one continuous wire. In any of these examples, the twisted braid may comprise multiple filaments. For example, it may comprise 2, 3, 4, 5, 6, 7, 8, 9, or 10 parallel filaments per bundle within the braid. The twisted braid may have a braid angle greater than about 30 degrees (e.g., 30 degrees or more, 35 degrees or more, 40 degrees or more, 45 degrees or more, 50 degrees or more, 55 degrees or more, etc.).

[0078] In any of these devices, the first coil wire and the twisted braid may be decoupled from one another. Alternatively, they may be coupled to one another at intermittent locations or discrete regions along the length of the flexible inner tube (including through the use of a matrix material). For example, the first coil wire and the twisted braid may be coupled to one another every 30 to 720 degrees of the helically wound coil wire (e.g., every 60 to 720 degrees, every 90 to 720 degrees, every 180 to 720 degrees, every 270 to 720 degrees, every 1 to 2 turns, every 1 to 5 turns, etc.).

[0079]

[0079] In any of these examples, the first coil wire and the twisted braid may be encapsulated in a material (e.g., an elastomeric material). For example, the material may be an elastomeric or polymeric material.

[0080] All of the methods and apparatus described herein can be used, in any combination, as contemplated herein to achieve the advantages as described herein.

[0081] A better understanding of the features and advantages of the methods and apparatus described herein can be obtained by reference to the following detailed description, which defines exemplary embodiments, and the accompanying drawings. [Brief explanation of the drawings]

[0082] [Figure 1A]

[0082] A cross-sectional view of an elongated rigidizable device that is rigidified by the application of negative pressure. [Figure 1B]

[0083] FIG. 1B is an enlarged view showing an example of the arrangement of layers within the elongated, rigidizable device of FIG. 1A. [Figure 2A]

[0084] FIG. 10 is a cross-sectional view of an elongated, rigidizable device being rigidified by the application of positive pressure. [Figure 2B]

[0085] 2B is an alternative cross-sectional view illustrating an example of layer arrangement within the elongated stiffening device of FIG. 2A. [Figure 3]

[0086] FIG. 1 shows an example cross-section of an example nested pair of rigidizable elongate devices arranged as a mother (or, e.g., catheter or overtube) and child (or, e.g., catheter or endoscope) pair. [Figure 4A]

[0087] 10A-10C illustrate examples of methods for operating nested pairs of elongated stiffening devices that selectively stiffen and unstiffen to propagate shapes through tortuous paths. [Figure 4B] FIG. 10 is a diagram illustrating an example of the method. [Figure 4C] FIG. 10 is a diagram illustrating an example of the method. [Figure 4D] FIG. 10 is a diagram illustrating an example of the method. [Figure 4E] FIG. 10 is a diagram illustrating an example of the method. [Figure 4F] FIG. 10 is a diagram illustrating an example of the method. [Figure 4G] FIG. 10 is a diagram illustrating an example of the method. [Figure 4H] FIG. 10 is a diagram illustrating an example of the method. [Figure 5A]

[0088] FIG. 10 illustrates an example of a stiffenable device including a braided stiffening layer, with the braided stiffening layer exposed. [Figure 5B]

[0089] FIG. 5B shows an example of a stiffenable device as shown in FIG. 5A with an outer layer covering the braided stiffening layer. [Figure 5C]

[0090] FIG. 2 is an enlarged view of an example of a knitted fabric. [Figure 5D]

[0091] FIG. 10 is a cross-sectional view of an example braid overlying an inner tubular member. [Figure 6A]

[0092] FIG. 10 is a diagram showing an example of weft knitting. [Figure 6B]

[0093] FIG. 10 is a diagram showing an example of warp knitting. [Figure 6C]

[0094] FIG. 1 shows an example of a knitted material formed from a single continuous filament. [Figure 7A]

[0095] FIG. 1 illustrates an example of a woven stiffening layer formed from filaments that may be used as part of a stiffenable device described herein. [Figure 7B]

[0096] FIG. 1 illustrates an example of a woven stiffening material formed of monofilaments woven together, which woven stiffening layer may be used as part of a stiffenable device as described herein. [Figure 7C]

[0097] FIG. 10 shows another example of a woven material. [Figure 8A]

[0098] 1A-1C show examples of braided materials used as (or as part of) the stiffening layer of a stiffenable device as described herein. [Figure 8B] FIG. 10 illustrates a discontinuous braided layer. [Figure 9A]

[0099] FIG. 10 is a schematic diagram illustrating stiffening of a pressure-activated stiffenable device. [Figure 9B] FIG. 10 is a schematic diagram illustrating stiffening of a pressure-activated stiffenable device. [Figure 10A]

[0100] FIG. 10 is a schematic diagram illustrating an example of a rigidizable device that integrates a compressible layer and a rigidification layer. [Figure 10B] FIG. 10B shows the rigidizable device of FIG. 10A being rigidified by applying positive pressure to the first gap region. [Figure 10C] FIG. 10B shows the rigidizable device of FIG. 10A being rigidified by applying positive pressure to the second gap region. [Figure 11A]

[0101] FIG. 1 is a schematic cutaway view of a portion of a rigidizable device having a stiffening layer formed of a plurality of adjacent segments having deformable members. [Figure 11B]

[0102] FIG. 11B is an enlarged perspective view of an example of a segment of a rigidizable device as shown in FIG. 11A. [Figure 11C]FIG. 11B is an enlarged side view of an example of a segment of a rigidizable device as shown in FIG. 11A. [Figure 11D]

[0103] FIG. 11B is a longitudinal cross-sectional view of a portion of the rigidizable device of FIG. 11A. [Figure 11E]

[0104] FIG. 11B shows another example of a longitudinal cross section of the rigidizable device of FIG. 11A. [Figure 11F]

[0105] FIG. 11B is an example cross-sectional view of the rigidizable device of FIG. 11A. [Figure 11G]

[0106] FIG. 11B is a perspective view of a rigidizable device similar to that shown in FIG. 11A. [Figure 12A]

[0107] FIG. 10 is a schematic diagram of another example of a rigidizable device having a rigidifying layer formed of a plurality of adjacent segments with a deformable member, the rigidizable device being a cutaway cross-sectional view. [Figure 12B] FIG. 10 is a schematic diagram of another example of a rigidizable device having a rigidifying layer formed of a plurality of adjacent segments having a deformable member, the rigidizable device being a partially exploded view. [Figure 12C] 12A-12B are schematic diagrams of another example of a rigidizable device having a rigidifying layer formed of a plurality of adjacent segments having deformable members, the diagrams being enlarged views of segments of the device of FIGS. 12A-12B. [Figure 12D] 12A-12B are cross-sectional views of another example of a rigidizable device having a stiffening layer formed of a plurality of adjacent segments with deformable members. [Figure 13]

[0108] FIG. 10 is a schematic diagram illustrating another example of a rigidizable device having a rigidifying layer formed of multiple segments. [Figure 13A] FIG. 1 shows spirally arranged segments with the outer layer removed. [Figure 13B] FIG. 2 is a cross-sectional view of the device. [Figure 14]

[0109] FIG. 1 illustrates an example of a rigidizable device having a stiffening layer formed of multiple sub-layers (e.g., scales). [Figure 14A] FIG. 1 shows an example of a device with the outer layer removed, showing the stiffening layer and inner layer. [Figure 14B] FIG. 10 shows an example of a sublayer (scale) used to form a stiffening layer. [Figure 14C] FIG. 2 is a schematic cross-sectional view of an example stiffening layer and inner layer. [Figure 14D] 1A-1C are schematic diagrams illustrating an example cross-section of a rigidizable device (e.g., a distal region of a rigidizable device) including a rigidizable layer formed from multiple sub-layers (e.g., scales). [Figure 15A]

[0110] 1 is a schematic cross-sectional view of a portion of a stiffening layer including multiple overlapping members. [Figure 15B]

[0111] FIG. 15B is a schematic cross-sectional view of a portion of a rigidizable device including the stiffening layer shown in FIG. 15A. [Figure 15C]

[0112] FIG. 15C is a diagram illustrating a schematic representation of the stiffening of the portion of the rigidizable device shown in FIG. 15B. [Figure 16A]

[0113] FIG. 10 is a schematic diagram illustrating an example cross section of a portion of a rigidizable device including a rigidifying layer comprising a plurality of granules. [Figure 16B]

[0114] FIG. 16B is the cross-sectional view of FIG. 16A when positive pressure is applied to stiffen the stiffening layer. [Figure 16C]

[0115] FIG. 16B is an enlarged view of area C in FIG. 16A. [Figure 16D]

[0116] FIG. 16C is an enlarged view of region D in FIG. 16B. [Figure 17A]

[0117] 1 is a cross-sectional view of a portion of a stiffening device that provides increased torsional stiffening. [Figure 17B]

[0118] FIG. 10 is a cross-sectional view of another example of a stiffening device that provides increased torsional stiffening. [Figure 18]

[0119] FIG. 1 is a cross-sectional view of an example of a portion of a stiffening device having a plurality of intersecting filament lengths or strands disposed within the body of the device, as well as a reinforced inner layer and a reinforced outer layer. [Figure 19]

[0120] FIG. 10 is a cross-sectional view of an example portion of a reinforced inner layer having regions of different durometer hardness. [Figure 20A]

[0121] 1A-1C are schematic diagrams illustrating examples of cross-sections of arrangements of rigidizable devices as described herein. [Figure 20B] 1A-1C are schematic cross-sectional views of exemplary placement of rigidizable devices. [Figure 20C] 1A-1C are schematic cross-sectional views of exemplary placement of rigidizable devices. [Figure 20D] 1A-1C are schematic cross-sectional views of exemplary placement of rigidizable devices. [Figure 20E] 1A-1C are schematic cross-sectional views of exemplary placement of rigidizable devices. [Figure 20F] 1A-1C are schematic cross-sectional views of exemplary placement of rigidizable devices. [Figure 20G] 1A-1C are schematic cross-sectional views of exemplary placement of rigidizable devices. [Figure 20H] 1A-1C are schematic cross-sectional views of exemplary placement of rigidizable devices. [Figure 20I] 1A-1C are schematic cross-sectional views of exemplary placement of rigidizable devices. [Figure 20J] 1A-1C are schematic cross-sectional views of exemplary placement of rigidizable devices. [Figure 20K] 1A-1C are schematic cross-sectional views of exemplary placement of rigidizable devices. [Figure 20L] 1A-1C are schematic cross-sectional views of exemplary placement of rigidizable devices. [Figure 20M] 1A-1C are schematic cross-sectional views of exemplary placement of rigidizable devices. [Figure 20N] 1A-1C are schematic cross-sectional views of exemplary placement of rigidizable devices. [Figure 21A]

[0122] FIG. 1 illustrates an example of a robot system having high torsional stiffness. [Figure 21B] FIG. 2 is a diagram illustrating an example of the robot system. [Figure 22]

[0123] FIG. 1 illustrates an example of a robotic system including an external working channel sleeve device as described herein. DETAILED DESCRIPTION OF THE INVENTION

[0083]

[0124] The rigidizable devices and methods described herein can be part of a medical access system for diagnosing and treating areas within the body that are otherwise difficult to access and manipulate, particularly during minimally invasive or non-invasive procedures. In particular, these methods and devices can be used in highly tortuous and / or unsupported areas of the body. These methods and devices can be used in combination with, and / or modifications and improvements to, the rigidizable devices and methods using those devices described below. No. 11,135,398 (entitled "DYNAMICALLY RIGIDIZING COMPOSITE MEDICAL STRUCTURES"), U.S. Patent Application No. 17 / 604,203 (entitled "DYNAMICALLY RIGIDIZING COMPOSITE MEDICAL STRUCTURES"), PCT / US2021 / 024582 (entitled "LAYERED WALLS FOR RIGIDIZING DEVICES"), PCT / US2021 / 034292 (entitled "RIGIDIZING DEVICES"), PCT / US2022 / 014497 (entitled "DEVICES AND METHODS TO PREVENT INADVERTENT MOTION OF DYNAMICALLY RIGIDIZING DEVICES"), and PCT / US2022 / 019711 (entitled "CONTROL OF ROBOTIC DYNAMICALLY RIGIDIZING "COMPOSITE MEDICAL STRUCTURES," U.S. Provisional Patent Application No. 63 / 265,934 entitled "METHODS AND APPARATUSES FOR REDUCING CURVATURE OF A COLON," and U.S. Provisional Patent Application No. 63 / 296,478 entitled "RECONFIGURABLE STRUCTURES."

[0084]

[0125] No. 63 / 308,044 entitled "DYNAMICALLY RIGIDIZING COMPOSITE MEDICAL STRUCTURES," U.S. Provisional Patent Application No. 63 / 324,011 entitled "METHODS AND APPARATUSES FOR NAVIGATING USING A PAIR OF RIGIDIZING DEVICES," U.S. Provisional Patent Application No. 63 / 342,618 entitled "EXTERNAL WORKING CHANNELS FOR ENDOSCOPIC DEVICES," U.S. Provisional Patent Application No. 63 / 335,720 entitled "HYGIENIC DRAPING FOR ROBOTIC ENDOSCOPY," and U.S. Provisional Patent Application No. 63 / 332,686 entitled "MANAGING AND MANIPULATING A LONG LENGTH ROBOTIC ENDOSCOPE," each of which is incorporated herein by reference in its entirety.

[0085]

[0126] Stiffening devices as described herein may be configured to stiffen upon application of negative and / or positive pressure. These stiffening devices as described herein may be used with other stiffening devices that stiffen in other ways, including those that do not rely on the application of positive or negative pressure. For example, a stiffening device may be configured to include multiple layers disposed on an elongate, catheter-like body. The device may include a handle or other manipulator and may include connections to one or more pressure sources. The application of pressure from the pressure source may be controlled by multiple methods, including operation of a handle or an electronic control device. The control provides a pressure differential that transitions the device between a highly flexible configuration in which the tubular body easily bends when manipulated or otherwise guided (e.g., over a guidewire) and one or more rigid configurations (e.g., a continuum). In some examples, particularly (but not exclusively) with respect to devices that stiffen based on the application of positive pressure, the stiffness of the elongate body is proportional to the applied pressure differential, such that a larger pressure differential may result in a more rigid device, at least over a range of pressure differential values.

[0086]

[0127] Generally, these devices may include multiple layers, including a stiffening layer and at least one of an outer layer or an inner layer. Many of these examples also include a compression layer engaged with the stiffening layer, and in some examples, the device may include a stiffening / compression layer combination. The stiffening layers described herein are particularly suited for rapid and accurate actuation against a variety of pressures, including particularly positive pressures (e.g., high positive pressures, i.e., 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 atmospheres). In any of these devices, at least a portion of the inner and / or outer layers comprising the rigidizable device may be configured to have different durometer hardnesses in the inner and outer portions of either the inner or outer layer. Additionally, the devices and methods including a nested set of rigidizable devices described herein may include any of these rigidizable devices. Any of these devices may include one or more torsion-enhancing layers for improved torsional control, particularly when included as part of a nested pair of rigidizable devices (e.g., as part of an inner or outer device).

[0087]

[0128] FIG. 1A shows an example of a cross-section of an elongated stiffening device, illustrating the arrangement of the many layers included. In this example, the stiffening device 100 is configured to be actuated by the application of negative pressure (e.g., vacuum). The illustrated device 100 includes an inner layer (115) that is reinforced (e.g., by including one or more reinforcing members, such as helically arranged strips, ribbons, or wires), an optional slip layer (113), a gap (111), a stiffening layer (109), configured in this example as a braided layer, a second gap (107), and an outer layer (101). In some examples, a vacuum may be applied between the outer and inner layers to stiffen them. For example, a port configured to couple to a negative pressure source may be located at the proximal end of the device and may be in fluid communication with the gap region 107 between the flexible outer layer 101 and the stiffening layer 109, e.g., a braided layer. Thus, in this example, the outer layer may act as a compression layer. 1B shows a cross section of one wall region B of the cylindrical body of the device. Upon application of suction, the outer layer 101 is drawn onto the stiffening layer, stiffening it and limiting or preventing bending of the device.

[0088]

[0129] Another example of a rigidizable device is shown in FIGS. 2A-2B. In this example, the device is also elongated, for example, a catheter- or tube-shaped device as in FIGS. 1A-1B, and may be rigidified by the application of positive pressure. For example, FIG. 2A shows a cross section of an elongated, rigidizable device taken along its long axis. In this example, the layers forming the device are arranged such that the inner reinforcement layer 2115 is the radially innermost layer and is reinforced, for example, by a spirally wound ribbon, strip, cable, or the like. The device may include an optional slip layer 2113 to reduce friction between the inner layer and the radially outer layer. The slip layer may be a powder or may be a lubricious layer or layer of lubricious material. A first interstitial layer 2112 is shown separating the inner layer 2115 and / or the slip layer 2113 from the compressed layer, which in this example is configured as a bladder layer 2121. A second (or middle) interstitial layer 2111 separates the bladder layer from the stiffening layer 2109, shown in this example as a braided layer. A third interstitial layer 2107 is positioned between the stiffening layer and the outer layer 2101. The outer layer in this example (like the inner layer 2115) is reinforced, for example, with helically wound filaments, wires, fibers, bands, etc. Although not shown, when actuated by applying positive pressure between the compressive (e.g., bladder) layer and the inner layer, the bladder layer pushes the braided layer into the outer layer, stiffening the stiffening layer.

[0089]

[0130] Both example devices shown in Figures 1A-1B and 2A-2B may include additional optional layers or components. Furthermore, the composition of the stiffening layer may be modified to enhance performance. In particular, the stiffening layer may be modified to include structures that enhance or improve performance (e.g., knits, wovens, braids, flakes, plates, filament arrays, granules, combinations thereof, etc.). Stiffening elements may be used alone or in conjunction with other stiffening 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 hardness of the inner and outer regions of these layers.

[0090]

[0131] Additionally, any of the stiffening devices described herein may be configured as nested systems to provide improved performance. For example, a nested system is shown in FIG. 3 and illustrated in operation in FIGS. 4A-4H. In FIG. 3, nested system 300 includes an outer stiffening device 301 and an inner stiffening device 302 (configured as a stiffening scope) that are axially and rotationally movable relative to one another. In this example, they move concentrically, but in some configurations, they may be arranged non-concentrically. External stiffening device 301 and internal stiffening device 302 may include any of the stiffening features described herein. For example, external stiffening device 301 may include an outermost layer (e.g., tube) 305, a stiffening (e.g., braided) layer 309, and an inner layer (e.g., tube) 315. Either or both of inner tube (layer) 305 and outer tube (layer) 315 may be reinforced, for example, by a wound coil. The external stiffening device 301 can be configured to stiffen, for example, by receiving a vacuum between the outermost layer 305 and the inner layer 315. Similarly, the internal stiffenable device (scope 302) can include an outer layer 325 (e.g., through which a coil is wound in this example), a stiffening (e.g., braided in this example) layer 329, a compressible layer 321 (e.g., configured as a bladder layer in this example), and an inner layer 335 (e.g., through which a coil is wound in this example).

[0091]

[0132] The internal stiffening device (e.g., scope 302) can be configured to stiffen under pressure, for example, between compressible layer 321 and inner layer 335. Any of these stiffening devices, including the internal stiffening device shown in FIG. 3, can include air / water channels 336 and working channel 355 that extend along with internal stiffening device 302. Additionally, any of these stiffening devices (including internal stiffening device 302 shown in FIG. 3) can include a distal portion 342 with a camera 365, a light 375, and an operable linkage 377. A shroud 379 can extend over the end of distal portion 342. In another example, the camera and / or light can be delivered in separate assemblies (e.g., the camera and light can be bundled together within the catheter and delivered to the distal end of the working channel and / or additional working channels). Features of any of these devices can include or be incorporated into devices that include a flexible external working channel that can be incorporated (as described in U.S. Provisional Patent Application No. 13668-719.100). No. 63 / 342,618, filed May 16, 2022, entitled "EXTERNAL WORKING CHANNELS FOR ENDOSCOPIC DEVICES," is incorporated herein by reference in its entirety.

[0092]

[0133] The inner lumen 381 of the first outer rigidizable device 301 can form a gap or interface 381 in which the second, inner rigidizable device is positioned. This gap or interface region 381 can have any suitable dimensions so that an annular space (d) remains around the second, inner rigidizable device when it is 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, the space d on either side of the inner rigidizable device can be between about 0.001 inch and 0.050 inch, e.g., 0.0020 inch, 0.005 inch, or 0.020 inch wide. The inner surface of the external stiffening device and / or the outer surface of the internal stiffening device may be a low-friction surface and may include, for example, a powder, a coating (e.g., hydrophilic or hydrophobic), or a laminate to reduce friction. In some examples, a seal may be present between the internal device 302 and the external stiffening device 301, and the intervening space may be pressurized with, for example, fluid or water to create a hydrostatic bearing. In other examples, a seal may be present between the internal stiffening device 302 and the external stiffening device 301, and the intervening space may be filled with small spheres to reduce friction.

[0093]

[0134] The internal rigidizable device 302 and the external rigidizable device 301 can be moved relative to each other to alternately stiffen the bend or length of the nested system 300. For example, the internal device 302 can be inserted into a lumen and bent or manipulated into a desired shape. Pressure can be applied to the internal rigidizable device 302, causing the stiffening layer to stiffen the internal rigidizable device 302 regardless of the curvature or bend in its configuration when the pressure was applied. The rigidizable device 301 (e.g., in a flexible state) can then be advanced over the rigid internal rigidizable device 302. Once the external rigidizable device 301 has been sufficiently advanced relative to the internal rigidizable device 302, pressure (e.g., negative pressure in this example) can be applied to the external rigidizable device 301 to stiffen the stiffening layer to fix the shape of the external rigidizable device. The internal rigidizable device 302 can be advanced in a flexible state, and the process can be repeated. Although system 300 is described as including an internal rigidizable device configured as a scope, it should be understood that other configurations are possible. For example, the system may include two overtubes, two catheters, or a combination of an overtube, a catheter, and a scope.

[0094]

[0135] 4A-4H illustrate the ability of these nested systems 400 to advance through highly tortuous anatomical structures with control from the proximal end of the device, while controlling the pressure (and therefore stiffness / flexibility) on both the internal rigidizable device 403 and the external rigidizable device 401. For example, FIG. 4A shows the nested system 400 initially inserted in a linear (straight) configuration. The distal end of the internal rigidizable device 403 may be steerable and may be extended from the external rigidizable device 401 while being steered to bend, as shown in FIG. 4B. The internal rigidizable device 403 may then be stiffened by application of a pressure differential, and the external rigidizable device 401 is advanced distally over the locked, curved shape of the rigid internal rigidizable device 403, as shown in FIG. 4C. Once at or near the distal end of the internal rigidizable device, the external rigidizable device may be stiffened (e.g., by a controller applying a pressure differential to the external rigidizable device), after which the internal rigidizable device may be transitioned to a flexible configuration. The internal rigidizable device 403 may then be advanced distally while being manipulated, and this rigid external rigidizable device may be used to advance and manipulate the stable platform, as shown in FIG. 4D . After being manipulated at least partially around a curve, the internal rigidizable device may again be stiffened, and the external rigidizable device may be made flexible and advanced distally over the rigid internal rigidizable device, as shown in FIG. 4E . The external rigidizable device may then be made rigid (by applying a pressure differential), and the internal rigidizable device may be made flexible and again advanced distally and manipulated, as shown in FIG. 4F ; once the internal rigidizable device has been manipulated distally to the desired extent, the internal rigidizable device may be stiffened, and the external rigidizable device may be made flexible and advanced distally over the internal rigidizable device, as shown in FIG. 4G . As shown in FIG. 4H, the external rigidizable device may be made rigid by applying a pressure differential as it is advanced to the end of the internal rigidizable device, and the internal rigidizable device may be made flexible and manipulated while being advanced distally.This process may be repeated as many times as necessary to position the device or any devices associated with the device in a shape-replicating manner. The device may be retracted and / or its path corrected by reversing this process and withdrawing the outer and inner rigidizable devices.

[0095]

[0136] 3 and 4A-4H are shown and described to generally illustrate a nested system and a method of operating the nested system with any of the rigidizable devices described herein. Referring to FIGS. 4A-4H, the exemplary nested apparatus may be stiffened by any suitable method, including, but not limited to, application of positive and / or negative pressure to one or both of the stiffening members. Modifications to the stiffening members, torsional stiffening, and / or durometer of the inner and / or outer layers (tubes) of these rigidizable devices may provide improved movement and functionality of the nested devices described herein when performing methods similar to those shown in FIGS. 4A-4H.

[0096] Knitted stiffening layer

[0137] Any of the stiffening devices described herein (and any nested systems or methods including them) may include a stiffening layer formed of a braided material or layer (e.g., a braided tube). A braided stiffening layer, which may be equivalently referred to herein as a braided stiffening layer or a braided stiffening layer, may be formed of a single fiber or braided from multiple fibers. The fibers forming the braid may be yarn, filament, monofilament, multiple filaments, strand, thread, wire, etc. The fibers may be made from natural or synthetic materials, including polymeric materials, metals and metal alloys, composites, or combinations thereof. In some cases, the braid is formed from a polymeric material. The fibers may be continuous, and each of the filament lengths forming the stiffening layer may be part of a single fiber, or may be segmented into multiple filament lengths. For example, a braid may be a single fiber that is segmented / cut at regular or irregular lengths.

[0097]

[0138] 5A and 5B show an example of a rigidizable device 500 including a braided stiffening layer (e.g., a tube) 505. In FIG. 5A, the outermost layer (outer layer 515) has been removed for clarity, while FIG. 5B shows a rigidizable device in which the outer layer 515 covers the other layers. This outer layer may be a reinforced outer layer, such as an externally coiled tube. In FIG. 5A, the rigidizable device includes a braided stiffening layer 505 that extends over the elongated body of the device, including over a compressible layer 507 (e.g., a bladder) and an inner layer 509. Both the inner and outer layers 515 may be reinforced. This example is similar to the configuration shown in FIGS. 2A-2B (with stiffening layer 2109 configured as a braided layer 505), but may be stiffened by applying positive pressure between the compressible layer 507 and the inner layer 509, which may drive the compressible layer radially outward relative to the outer layer 515. 2A-2B may be optionally included, including the gap regions / layers and optional slipping layer (which may not be required). This configuration may alternatively be actuated by application of negative pressure between the outer layer and the compression layer (including the knitted region), where the vacuum may pull the compression layer against the knitted layer to stiffen the layers.

[0098]

[0139] 5A-5B may alternatively be configured to apply positive pressure between a compressible layer (e.g., a bladder) and the outer layer 515 (external stiffening layer). In some examples, the compressible layer may be positioned between the outer layer and the knitted stiffening layer, such that positive pressure applied between the outer layer and the compressible layer may drive the compressible layer against the knitted layer, thereby stiffening the knitted layer into the inner (stiffening) layer. As in the configuration shown in FIGS. 5A-5B, the device may alternatively be actuated by, for example, application of negative pressure between the inner layer and the compressible layer (including the knitted region).

[0099]

[0140] Alternatively, a stiffening device including a knitted stiffening layer may be configured as shown in Figures 1A-1B and may be actuated by application of negative pressure. In some examples, an outer or inner layer may be configured as a compressible layer (e.g., a bladder) and may engage the knitted stiffening layer when a vacuum is applied. Examples of these alternative arrangements may include a knitted stiffening layer, as described below in Figures 20A-20N.

[0100]

[0141] FIG. 5C shows an example of a portion of a knitted layer 505 formed with a single filament 518 forming interlocking loops. In the example shown in FIG. 5C, the knit includes multiple stitch loops, each having a length y, and curved head and foot regions having a length x. The stitch pattern shown in FIG. 5C is a weft knit pattern, although other knit patterns may be used. FIG. 5D shows an example of a cross-section of a knitted layer positioned adjacent to a compaction layer 507. In this example, the knitted layer is a tube having 28 strand segments formed into loops from the same strand (e.g., 14 loops arranged with the wales of the knit parallel to the long axis of the device). The knitted tube has a diameter z, and the spacing n between adjacent loops is approximately equal around the circumference of the knitted tube. The spacing between the stitch width p and the spacing n may vary along the length of the knitted tube. Dimensions are for illustrative purposes only.

[0101]

[0142] FIGS. 6A-6B show two different examples of knitting patterns 600, 600' that can be used. FIG. 6A shows a weft knit similar to that shown in FIG. 5C. In this example, the knit is formed from one or more strands (which may be continuous or broken / cut) to form stitch loops 602, each including a head region 604, a pair of legs 606, and first and second feet 608, each of which engages the head of a stitch loop in a course above or below the original stitch loop course. The connection between the feet of adjacent stitch loops may be referred to as a sinker (if the knit is rotated 180 degrees, the sinker corresponds to the head). In FIG. 6A, the wale direction 612 runs up and down, and the courses 610 run from right to left. Typically, wales are columns of loops that run lengthwise and correspond to the warp threads of the woven fabric in FIG. 6A. The courses are rows of loops that correspond to the fill of the resulting knit.

[0102]

[0143] FIG. 6B shows an example of a warp knit 600′. In this example, the warp knit also has courses 610′ and a wale direction 612′, but the foot of each loop engages with the head region of a knit loop in an offset row (course direction) as shown, forming a long pattern of overlaps 612 and underlaps 614. The knitted stiffening layers described herein may be oriented (course direction or wale direction) relative to the elongate axis (length) of the device using any suitable pattern. For example, the knitted structure (knitted stiffening layer) may be configured such that the wale direction of the knitted fabric extends along the long axis of the flexible tube. Alternatively, the knitted structure may be configured such that the wale direction of the knitted structure is perpendicular to the long axis of the flexible tube. Depending on the stitch length (y) relative to the loop diameter (p) and / or the spacing (n) between associated loops, it may be beneficial to orient the knitted stiffening layer so that either the wales or courses are oriented parallel or perpendicular to the long axis of the elongate body of the rigidizable device. In any of the examples described herein, the knitted structure may have an average loop length that is longer than the loop width. For example, the loop length may be two or more times (e.g., three, four, five, six, seven, eight, nine, ten, twenty, forty, sixty, eighty, one hundred, or more) the average loop width. Knitted fabrics (including knitted tubes) are particularly useful in the stiffenable devices described herein because they can be stretched and compressed when bent without buckling or wrinkling.

[0103]

[0144] As shown in FIG. 6C , the braided stiffening layer 600″ may be formed of a single braided fiber 618. As mentioned above, the fiber may be formed of a single filament (monofilament) or a bundle of filaments (multifilament). Thus, the illustrated pattern includes multiple filament lengths (e.g., rows of filament lengths) that cross each other in the braided pattern. In FIG. 6C , the multiple filament lengths that cross over and under each other are all part of the same fiber or strand. In some examples, the braided fiber or strand may be cut or severed into multiple separate filament lengths. The braided material (e.g., fiber) may be formed of any suitable material, such as a metal, a metal alloy, a polymeric material, a natural fiber, etc.

[0104] Woven and Braided Stiffening Layers

[0145] Any of the rigidizable devices (and any nested systems or methods including them) described herein may include a woven stiffening layer. Figures 7A-7C show an example of a woven stiffening layer 705 used as a stiffening layer in a rigidizable device and arranged as shown in Figures 1A-1B, 2A-2B, or 20A-20N. In Figure 7A, the weave includes multiple parallel fibers forming a set of intersecting fibers; in Figure 7A, the fibers cross each other at a 90-degree angle, although this angle may vary (e.g., between about 30 and 150 degrees, between 45 and 135 degrees, between 50 and 130 degrees, between 70 and 110 degrees, between 80 and 100 degrees, etc.). The pattern of intersecting filament lengths (e.g., a row of filament lengths) includes individual filament lengths crossing over and under each other, as shown, with a first filament length 718 crossing over a second filament length 728 and under a third filament length 725. In this example, the pattern is shown as an over-and-under pattern, but this pattern may be different in other examples of stiffening layers; in FIG. 7A, the pattern is one over and one under. In some examples, the pattern may be two over and two under, two over and one under, etc. Any suitable fiber (e.g., strand) may be used to form the stiffening layer, as described above for the knitted stiffening layer. In the woven stiffening layer shown in FIG. 7A, the fiber is a multifilament fiber including bundles of multiple filaments forming each strand. FIG. 7B shows an example of a woven stiffening layer 705′ formed of monofilament and arranged with parallel strands 718′, 728′ arranged in a woven pattern similar to that shown in FIG. 7A. The woven pattern can be of any desired density (e.g., pore size). Generally, as shown in FIG. 7C, a plurality of different length fibers 718", 728" are used to form the woven pattern 705".

[0105]

[0146] 8A and 8B show examples of a braided stiffening layer. In FIG. 8A, the braid 800 is formed of multiple fibers 818, 828 arranged in an up-and-down pattern with a braid angle relative to the long axis (e.g., the long axis of the device when included as a stiffening layer). Generally, the braid angle (relative to the centerline along the central axis) of the braided stiffening layer (tube) can be 45 degrees or less (e.g., less than 45 degrees, 40 degrees or less, 35 degrees or less, 35 degrees or less, 30 degrees or less, 20 degrees or less, 20 degrees or less, etc.). In FIG. 8A, the different filaments forming the braided layer are continuous and uninterrupted. However, in some instances, it may be beneficial to include breaks or cuts, as illustrated in FIG. 8B. In this example, the material includes multiple breaks or cuts 838 in the braided strands. While such an arrangement may not be desirable in a fabric or even in a braid used as part of a medical device, this broken (e.g., disrupted or cut) arrangement can be beneficial in a stiffening layer. Thus, in FIG. 8B, the braid pattern 800′ forming the stiffening layer (e.g., stiffening tube) can provide increased flexibility in the non-stiffened configuration while providing a high degree of stiffness in the actuated state. Thus, in FIG. 8, strands 818, 828′ cross over and under each other in the braid pattern shown, with periodic cuts 838 along their lengths. The number or density of cuts may vary; in some instances, a fiber may be cut every time it crosses over or under another fiber, while in other instances, a fiber may be cut every two (or three, or four, or five or more) crossings. The cut pattern may be non-uniform. In some instances, it may be beneficial to have cuts and discontinuities distributed at a density of between about one cut / discontinuity every third crossing (e.g., between every second and every twenty-fifth crossing, between every third and every twenty-first crossing, etc.).

[0106]

[0147] Other stiffening layers (e.g., knitted, woven, etc.) may also include discontinuities or cuts, which may be formed during manufacture by laser cutting, mechanical cutting, or any other suitable cutting technique.

[0107] Pressure-driven stiffening

[0148] As mentioned above, generally, these devices may be configured to be stiffened by the application of pressure. This is shown schematically in FIGS. 9A-9B for a typical stiffening layer. In this example, the device is shown in longitudinal cross-section of a portion of the device's length. The layers forming the device are arranged as concentric tubes. In FIG. 9A, the device is shown without the application of pressure and includes an inner layer (tube) 954, an outer layer (tube) 948, a compressible layer (e.g., bladder) 950, and a stiffening layer 952. The particular configuration shown shows the stiffening layer 952 between the inner layer 954 and the compressible layer 950. A first interstitial layer 956 is present between the outer layer 948 and the stiffening layer 952. Ports (not shown) may be present at the end (e.g., proximal end region) of the device that connects to a pressure (e.g., positive pressure) source. A second interstitial layer may be present between the compressible layer 950 and the stiffening layer 952 and / or between the stiffening layer 952 and the inner layer 954. 9A, the device may be flexible because each of these layers may slide relative to one another when the device is bent. In particular, the stiffening layer may bend and slide relative to the inner layer 954 and the compressible layer 950.

[0108]

[0149] Figure 9B shows the device of Figure 9A when positive pressure 960 is applied between the outer layer 948 and the compressible layer 950. Alternatively, the compressible layer may be a bladder to which positive pressure is applied. In Figure 9B, when positive pressure is applied, the compressible layer 950 is driven 961 against the stiffening layer 952, thereby compressing between the compressible layer 950 and the inner layer 954 (and / or any intervening layers). Compressing the stiffening layer 952 stiffens the device. The bend or curve is retained without changing shape.

[0109]

[0150] In the example shown in Figures 9A and 9B, any suitable stiffening layer 952 may be used, including a knitted compression layer, a weave, a braid, granules, flakes, or the like.

[0110]

[0151] In some instances, particularly those having a resilient (e.g., elastomeric) compressive layer and a stiffening layer formed of filament lengths crossing over and under each other, the compressive layer can deform into the stiffening layer, thereby increasing the stiffness of the device. For example, when pressure is applied, the compressive layer (e.g., a bladder) exerts a force directly on the stiffening layer. Depending on the type of bladder, the bladder may deform, depress, or interlock around elements (e.g., filaments, wires, etc.) of the stiffening layer into the spaces between them. Conforming to overlapping (overlying and underlying) fiber or filament lengths helps lock the stiffening layer against the inner layer (or in some instances, outer layer) against which it is compressed. Thus, applying positive pressure in this manner increases the positive pressure more than expected, thereby increasing stiffness. Thus, a stiffening layer including multiple filament lengths crossing over and under each other may be generally configured such that, in a flexible configuration, the filament (e.g., fiber) lengths shear relative to each other. However, when positive pressure is applied, the deformable compression layer is forced against the stiffening layer, causing the compression layer to conform to or deform into or between the multiple filament lengths to prevent the multiple filament lengths from shearing relative to one another.

[0111] Combination of stiffening and compression layers

[0152] In some examples, the rigidizable devices described herein may include a combination or hybrid of a stiffening layer and a compressible layer. Rather than the discrete stiffening layer described above, in some cases, the stiffening layer may be integrated (e.g., encapsulated, laminated within, etc.) into the deformable compressible layer. This configuration, sometimes referred to as a stiffening layer, may be described as an array of filament lengths encapsulated within the compressible material. The array of filament lengths may be configured to slide (e.g., shear) over one another when the compressible material is in a first, uncompressed configuration, and the array of filament lengths engage one another to prevent sliding when the compressible material is in a second, compressed configuration. In this example, the filaments may be partially encapsulated within the compressible material, in some cases encapsulated within channels or passages through the compressible material for individual or groups (e.g., at intersection regions) of fibers. Deforming the compressible material by application of pressure increases shear forces on the filaments, especially when two or more filaments overlap one another.

[0112]

[0153] This configuration works with either negative pressure (vacuum) or positive pressure. For example, positive pressure may be applied from the outside of the stiffening layer (driving the compressed material against the fibers (filaments) enclosed within). Negative pressure may be applied within the compressed material, e.g., within the channels holding the filaments, collapsing the channels into / onto the filaments.

[0113]

[0154] 10A-10B show an example of a rigidizable device 1000 including a combined stiffening and compressible layer 1051 in which filament lengths 1005 are loosely encapsulated within a compressible material 1003. The filament lengths may be continuous or discrete, but may include regions where two or more lengths cross over each other and shear 1009 within the compressible material. In some examples, it may be preferable to have discrete, relatively short filament lengths (e.g., between 0.2 cm and 10 cm, between 0.5 cm and 10 cm, between 0.5 cm and 7 cm, etc.). The filament lengths may cross over each other in a pattern, such as a weave or mesh pattern, or in a random pattern. In FIG. 10A, the device is shown in a flexible state in which the filaments move freely within the compressible material. The filaments may be monofilaments or multifilaments and may be formed of a polymeric material, a metal or metal alloy (e.g., wire), or any other suitable material or combination thereof. As shown, the rigidizable device 1000 also includes an outer layer (tube 1048) formed of an elongated flexible tube and an inner layer (tube 1054) also formed of an elongated flexible tube. Either or both of the inner and outer layers may be reinforced. The device includes an inner lumen 1021. As with any of the devices described herein, the device may be configured to experience minimal (e.g., less than 5%) or no change in inner and / or outer diameter under the application of relatively high pressure or vacuum. A stiffening layer 1051 (comprising loosely encapsulated lengths of filament) may be positioned between the outer and inner layers and may be separated by gaps, such as first gap 1056 and second gap 1017.

[0114]

[0155] FIG. 10B illustrates an example of a device that is actuated by the application of positive pressure 1060 between a second gap, e.g., inner layer 1054, and rigidizable layer 1051, resulting in compression of rigidizable layer 1051 against outer layer 1048 as shown. Within rigidizable layer 1051, compression deforms the compressible layer, dramatically increasing shear forces on the filaments within the loosely enclosed channels holding the filaments. The rigidizable layer 1051 may be thin and configured to compress under positive pressure. Thus, in FIG. 10B, compressing the rigidizable layer 1051 along its length can stiffen the rigidizable layer 1051 by preventing shearing of the filament strands.

[0115]

[0156] Alternatively, in some examples, positive pressure may be applied to a first gap region 1056 between the outer layer (tube 1048) and the rigidizable layer 1051 (not shown) to drive the compressible layer against the inner layer 1054.

[0116]

[0157] 10C shows an example of stiffening the rigidizable device of FIG. 10C by application of negative pressure within the rigidizable layer 1051, e.g., within channels in which the filament is loosely enclosed. Applying a vacuum within these channels can collapse the channels against the filament, similar to the application of external positive pressure. In some examples, positive pressure may be applied within the channels to make the device more flexible, and the device may be stiffened by removing the positive pressure and / or by applying negative pressure to further stiffen it.

[0117] Stiffening layer with sublayers (e.g., fingers, scales, and / or plates)

[0158] In some examples, a rigidizable device may include a stiffening layer with sublayers configured as fingers, scales, and / or plates. The sublayers may be actuated by the application of pressure (e.g., positive pressure) against either the other fingers, scales, and / or plates or against another layer (e.g., an inner or outer layer) of the device to stiffen them. They may be flat or rounded in shape. Their surfaces may be textured, surface-modified, adhesive, have shear load-transmitting features, or have frictionally engineered surfaces. These sublayers may be flexible in bending yet highly stiff in the axial direction. For example, FIGS. 11A-11G show an example of a device including multiple segments 1171, each including multiple radially arranged arms or fingers 1172 extending from an attachment region 1173. These sub-layers may or may not overlap other arms, and application of positive pressure (e.g., from a compressible layer) presses one sub-layer against another to stiffen the device. For example, Figure 11A shows a cross section of an example of a rigidizable device 1100 having a stiffening layer including a reinforced outer layer (tube) 1115, a compressible layer 1150, a reinforced inner layer 1109, and multiple axially arranged segments 1171.

[0118]

[0159] 11B and 11C show views of the segments separated. In this example, the segment includes multiple arms 1172 extending from a ring-shaped mounting portion 1173. The segments may be made of a flexible material (metal, polymer (Mylar, PEEK, PEN), composite, etc.) such that the arms are deflected, preferably radially inward or outward, by a compression layer (e.g., bladder 1150) when actuated, for example, by positive pressure. FIG. 11D shows a cross section of a portion of the device 1100 of FIG. 11A. In FIG. 11D, segment 1171 is positioned between the compression layer 1150 (e.g., bladder) and the inner layer 1109. A void 1179, fluidly connected to an inlet for coupling to a positive pressure source (not shown), is positioned between the outer layer 1115 and the compression layer 1150. In this example, the segments do not overlap, at least in the unflexed configuration shown. Thus, a series of segments 1172 may be arranged along the length of the device in a spaced apart configuration, as shown in Figure 11E. In some examples, the device may include spaces or gaps between the segments 1172 that are large enough to prevent overlap between them when the device is bent.

[0119]

[0160] FIG. 11F shows a radial cross-section of the rigidizable device 1100 of FIGS. 11A-11E at line F in FIG. 11E. The outer layer (tube) 1115 may be reinforced, e.g., an external coil-wound tube, and the inner layer (tube) 1109 may also or alternatively be reinforced, e.g., an internal coil-wound tube. The compression layer 1150 is between the attachment portions of the segments 1173. FIG. 11G shows a perspective view of a portion of the rigidizable device shown in FIGS. 11E and 11F. When pressure is applied through an inlet in fluid communication with the gap region, the compression layer (e.g., a bladder) compresses the segment arms 1272 against the inner tube (e.g., inner coil-wound tube ICWT), stiffening the device. The greater the applied pressure, the greater the stiffness of the device may be. This stiffening is achieved by forcing the sub-layers (arms, scales, etc.) against adjacent layers, such as the inner layer (inner tube) or outer layer.

[0120]

[0161] In some examples, longitudinally adjacent members (e.g., segments) are configured to overlap one another in addition to being adjacently positioned along the length of the device. For example, FIG. 12A shows a portion of a rigidizable device 1200 in a first exploded view, and FIG. 12B shows an alternative exploded view of the same rigidizable device. In this example, the device includes multiple adjacently overlapping members (e.g., segments in this example) having multiple scales, plates, or arms 1272, 1272′ extending from a central annular attachment segment 1273. The attachment segment 1273 may extend completely or partially around the radius of the device. In this example, in contrast to the segments shown in FIGS. 11A-11G, the arms 1272, 1272′ extend both distally and proximally from the attachment segment 1273. The device also includes an outer layer (eg, outer coil-wound tube OCWT) 1215 , an inner layer (eg, inner coil-wound tube ICWT) 1209 , and a compression layer (eg, bladder) 1250 .

[0121]

[0162] In Figures 12A-12D, the segments 1271 are configured to overlap one another so that the arms 1272, 1272' overlap radially. As shown in Figure 12C, the segments are configured so that the distally extending arms fit over the proximally extending arms from adjacent segments. As in Figures 11A-11G, the segments may be made of any suitable material, particularly a material that is elastically deformable when compressed together to stiffen the device. For example, the segments may be formed of a polymeric material or a metal or metal alloy. In this configuration, the material has low bending stiffness but high axial stiffness.

[0122]

[0163] Figure 12D shows a cross section of an assembled rigidizable device, as shown in Figures 12A-12C. In the non-rigidified (flexible) configuration, the device is relatively free to bend, with adjacent overlapping sublayers (e.g., arms, scales, plates, etc.) freely sliding over one another. However, application of positive pressure to drive a compressible layer against a rigidifying layer formed of multiple segments containing deflectable sublayers (e.g., arms, scales, plates, etc.) stiffens the device, regardless of whether the device was bent or curved when the positive pressure was initially applied; the greater the positive pressure differential, the greater the stiffness. In this example, the plates cannot easily slide over one another or against the inner layers.

[0123]

[0164] Another example of a stiffening layer formed of multiple sublayers (e.g., multiple segments containing sublayers, as in FIGS. 11A-11G and 12A-12D) is shown in FIGS. 13A-13B. In this example, rather than an annular ring of segments with sublayers extending from an attachment region, the stiffening layer is a plurality of overlapping sublayers (e.g., arms, scales, plates, etc.) arranged in a spiral or spirally wrapped configuration. FIG. 13A shows an example of a portion of a stiffenable device, showing multiple sublayers 1372 (e.g., curved plates) arranged around an inner layer (tube) 1309 and overlapping adjacent plates. The sublayers 1372 are shown extending from a spirally wrapped attachment region 1373, although one or more attachment regions may be used. FIG. 13B shows a portion of a stiffenable device 1300 including the stiffening layer 1354 of FIG. 13A. The device also includes an inner layer 1309, which may be reinforced, an outer layer 1315, a compressible layer 1350 (e.g., a bladder), and a spirally wound stiffening layer 1354 including multiple sublayers 1342 extending from an attachment region 1373. Application of positive pressure drives the sublayers against each other and (in this example) against the inner layer, stiffening the device.

[0124]

[0165] 14A-14D show another example of an apparatus (e.g., device) including a stiffening layer formed of multiple sublayers, shown in this example as scales 1408. As shown in FIG. 14A, the scales can be attached as separate elements, e.g., attached to an inner layer (tube) 1410. As discussed above, the scales can be configured to slide over each other or spaced apart so they do not overlap. In FIG. 14A, the scales are attached to the inner layer 1410 by attachments 1406 (e.g., ties, adhesive, welds, etc.) that flexibly attach the scales. In FIG. 14A, the scales that form the stiffening layer are attached to the base structure (braid) of the inner layer 1410 by knotted sutures. Alternatively, the sublayers (scales) can be attached to a central "spine" 1406' (e.g., a wire or substrate connecting the scales), as shown in FIG. 14B. This spine 1406' may be attached at one end and slide at another end as the structure is bent or articulated, in which case the length of the inner or outer passages may change. Figure 14C shows a cross section of a stiffening layer formed by multiple overlapping scales 1408 and an inner layer 1410.

[0125]

[0166] FIG. 14D schematically illustrates a partial longitudinal cross-section of a portion of the wall of an example of a rigidizable device in which the stiffening layer is formed of multiple overlapping sublayers (e.g., scales). In this example, an outer layer (e.g., OCWT) 1420 is radially outward (from the centerline of the device) of a compressible layer (e.g., bladder 1412), which is between the stiffening layer 1408 and the outer layer. The stiffening layer scales 1408 may be attached to or simply overlap an inner layer (e.g., ICWT) 1410, which comprises a braid. In this example, the illustrated device portion also illustrates a manipulation assembly including multiple bendable (e.g., hinged) links 1414 taken from the distal tip region 1406 and cables 1418 (held relative to the links by one or more slidable mounts 1416) that can be pulled to bend and manipulate the distal tip. Any of the devices described herein may include a similar arrangement of manipulation links and tendons (e.g., cables). In this example, the links and tendons may be positioned radially inward from the inner layer (tube), e.g., within the internal lumen of the device. Alternatively, the manipulable assemblies (e.g., links and tendons / cables) may be integrated into the device radially outward from the inner layer.

[0126]

[0167] 15A-15C show another example in which multiple overlapping arms extend radially in parallel to engage adjacent arms. In FIG. 15A, a stiffening layer 1454 includes multiple sublayers 1472, 1472′ extending from an attachment region 1473. The sublayers may be configured as arms, plates, scales, etc., and may freely slide relative to one another when pressure is not applied. The stiffening layer may include multiple attachment regions (e.g., as multiple distinct segments similar to those shown in FIGS. 11A-11G and 12A-12D) or a single spirally wound attachment region similar to that shown in FIGS. 13A-13B. FIGS. 15B and 15C show an example of a device 1400 including a stiffening layer 1454 similar to that shown in FIG. 15A. The device may also include an outer layer 1415, an inner layer 1409, and a compressible layer 1450. Figure 15B shows a device without a pressure differential; the device is highly flexible because the inner, outer, and stiffening layers are all highly flexible. Figure 15C shows the same device with positive pressure 1460 applied between the outer layer 1415 and the compressible layer 1450, for example, in the gap region 1479, driving 1461 the compressible layer against the stiffening layer so that the arms 1472 of the stiffening layer compress against each other, stiffening the device. The more pressure applied, the greater the stiffness.

[0127] Stiffening layer with granules / particles

[0168] In some examples, the rigidification layer of a rigidifiable device may include granules (e.g., particles) that are transformed from a loose, flexible configuration to a packed, rigid configuration "squeezed" together by the application of pressure, particularly positive pressure. In some examples, the granules are held within a flexible, compressible container (bag, cylinder, etc.) that is permeable to air, and a separate compression layer (e.g., bladder) is driven against the granules (e.g., against the container) to compress the granules, allowing air to escape from the container, but helping to more effectively retain the medium. Alternatively, in some examples, the compression layer may form part of the container.

[0128]

[0169] For example, Figures 16A-16D show an example of a rigidizable device 1500 including a rigidification layer formed of particles 1552 that can be rigidified by the application of positive pressure. The device includes an outer layer (e.g., a tube) 1515, an inner layer (e.g., a tube) 1509, and a compressible layer 1550, which in this example is between the outer layer and the rigidification layer. Alternatively, the compressible layer may be between the inner layer and the rigidification layer. A void may be between the compressible layer and the outer layer, a second void may be between the compressible layer and the rigidification layer, and a third void may be between the rigidification layer and the inner layer. Thus, all of these layers slide together in the flexible configuration, allowing the device to bend and flex. The particles or granules within the rigidification layer may be loosely packed, making the rigidification layer highly flexible in the unpressurized configuration. The device may also include a release path for releasing air from the rigidification layer (e.g., between the granules) when compression is exerted by the compressible layer. For example, Figure 16B shows stiffening of device 1500 of Figure 16A. In this example, positive pressure 1560 is applied into gap 1556 and / or the bladder (of compressible layer 1550), causing the compressible layer to be driven as shown against the stiffening layer. The granules or particles in the stiffening layer are packed and prevent depression against inner layer 1509, stiffening the device without significantly changing the profile of the device.

[0129]

[0170] 16C and 16D show enlarged cross-sections of FIG. 16A (flexible configuration) and FIG. 16B (rigid configuration), respectively. As shown in FIG. 16C, the rigidizing layer 1552 includes a plurality of loosely packed granules or particles. In FIG. 16D, the compressible layer 1550 drives the packing of the granules or particles in the rigidizing layer 1552′, which in this example is compressed between the compressible layer and the inner layer. The amount of packing and the achieved stiffness depend on the applied pressure and, in some examples, the shape and / or size of the particles or granules. Generally, the granules may be any suitable material, typically a rigid or semi-rigid material (e.g., polymer, metal, etc.). That is, they are either incompressible or resiliently compressible. In some cases, the granules may be formed of a biocompatible and / or bioabsorbable material to prevent harm to the patient if the device ruptures. The granules can have any suitable shape, for example, the granules can be round, square, faceted (e.g., crystalline), etc. In some examples, the shape of the granules can be uniform or non-uniform. The granules can include both uniform and non-uniform shapes, but can also include a variety of different shapes and / or sizes in the same stiffening layer.

[0130] Torsional stiffener

[0171] Creating a close relationship between proximal input rotation and resulting distal output rotation has multiple clinical benefits. Ideally, this ratio is one-to-one (e.g., 360 degrees of input rotation results in an equivalent 360 degrees of output rotation). This benefit is magnified in mother-child (e.g., nested or endoscope-overtube) systems, where the mother device provides a rigidified tube through which the child can rotate about its internal central axis. This allows for highly precise, central-axis-directed rotation in distal anatomy that cannot be achieved with an endoscope alone. This allows users to reorient the camera or tool, enabling tools that can grasp and precisely manipulate local tissue. This is valuable for both manual and robotic systems. For example, in a robotic system, the user can precisely titrate rotation down to very small increments (e.g., one degree or less) simply by pressing a button on a control device. This degree of control is powerful and previously unattainable.

[0131]

[0172] For example, with a 360-degree rotation input, the rotation output will be 360 ​​degrees, 350 degrees, 340 degrees, 330 degrees, 320 degrees, 310 degrees, 300 degrees, 290 degrees, 280 degrees, 270 degrees, 260 degrees, 250 degrees, 240 degrees, between about 180 degrees and 240 degrees, etc. This is done at some clinically meaningful amount of flexion; for example, the data can be normalized to a situation where the device rotates through a 360-degree curvature. Figures 21A and 21B show an example cross-section of a system including a torsion stiffening device. In Figure 21A, the device includes an external stiffening device (mother) 2201 and an internal stiffening device (child) 2203. The device is shown in a straight configuration. Applying a torque (e.g., rotation or twist) 2223 to the internal stiffening device in a first direction at any selected angle (e.g., 1 degree, 2 degrees, 3 degrees, 4 degrees, 5 degrees, 10 degrees, 15 degrees, etc.) causes the distal end region of the internal stiffening device to rotate 2225 by the same selected angle. Generally, torque from the proximal end of the internal stiffening device is faithfully transmitted to the distal end of the internal stiffening member even when the internal stiffening member is in a flexible configuration. The external stiffening device may be stiffened when a torque is applied to the (flexible) internal stiffening device.

[0132]

[0173] Importantly, the devices described herein also faithfully transmit torque along the entire length of the internal stiffening device, even when the device is bent in an arbitrarily curved path, as shown in FIG. 21B. In FIG. 21B, the outer device (or mother) 2201 has a circular shape (i.e., shown as a 360-degree curvature in this example), and the inner device (or child) 2203 is inserted inside. Once the mother is stiffened, a torque is applied to the child in a flexible configuration, and for a given input torque (rotational input) 2223, the rotational output of the child is measured. In the examples described herein, the device is configured so that the output torque is approximately the same as the input torque. For a given input rotation, approximately the same output rotation (e.g., input rotation + / - lag margin) can occur even when the device is in a highly curved configuration. The lag margin may be relatively low (e.g., 15% or less, 14% or less, 13% or less, 12% or less, 11% or less, 10% or less, 9% or less, 8% or less, 7% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, etc.). For example, for an input rotation of 360 degrees, a lag margin of approximately 8.3% would achieve an output rotation of 330 degrees. The devices described herein may include a torsion stiffening layer as described above with reference to FIGS. 17A-17B and may be configured to provide a relatively low lag margin. Any of these devices may be configured to reduce drag between the internal stiffening device 2003 and the external stiffening device 2001. For example, a lubricious material may be used. In some examples, the outer surface of the internal stiffening device and / or the inner surface of the external stiffening device may be lubricated and / or formed of a lubricious material. The lubricious material may be a hydrophobic or hydrophilic material. In the example shown in Figure 21B, the flexible inner stiffening device may be driven against the inner wall of the rigid outer stiffening device as torque is applied to the inner device. While Figures 21A-21B show torquing of the inner stiffening device relative to the outer stiffening device, either of these devices may be configured to faithfully transfer torque when the outer stiffening device (e.g., including a torsional stiffening layer) is rotated relative to the inner stiffening device.For example, the external stiffening device is torqued in a flexible configuration when the internal stiffening device is stiffened, so that the external stiffening device transmits torque faithfully along the length of the device, e.g., with high fidelity (e.g., very low lag margin).

[0133]

[0174] Generally, torquing (e.g., rotating) a device, e.g., an internal device and / or an external device, may be performed manually, automatically (e.g., robotically), or semi-automatically. For example, a robotic system may include one or more motors that drive rotation. In FIGS. 21A and 21B, an example includes a user input device 2227 that includes one or more inputs for controlling movement (rotation, and in some examples, other manipulation controls). For example, as shown schematically in FIGS. 21A and 21B, the user input device 2227 may include control inputs such as a clockwise rotation button, a counterclockwise rotation button, etc. These controllers may be processed by software, algorithms, and / or actuators.

[0134]

[0175] Any of the devices described herein may include a torsionally stiffening element. In particular, the high pressure devices described herein may include a torsionally stiffening layer. The torsionally stiffening layer may be integrated into the inner and / or outer layers. Alternatively, it may be a free-floating layer that is not intentionally attached to adjacent layers. For example, a stiffening device may include a flexible inner tube configured to provide torsion stiffening. The flexible inner tube may include a first coil (e.g., wire, ribbon, etc.). It may include a secondary or additional coil. It may also include a torsion braid and a flexible material at least partially surrounding or between the coil and the torsion braid. The flexible material may form the main body of the tube. A device including a flexible inner tube with a torsionally stiffening layer may also include a flexible outer tube, a stiffening layer between the inner and outer tubes, an inlet configured for attachment to a positive pressure source, and a compression layer. The flexible material may function as one of the leak-proofing elements for the stiffening. Alternatively, it may comprise an internal coil wound tubing (ICWT) structure, but need not be explicitly leak-proof. For example, as shown in FIG. 20B, both leak-proof pressurizing members may be bladders. This bladder 221b may be "out-and-back" (i.e., attached at only one end), as shown in FIG. 20B, or may be two different tubes joined at either end 2217, as shown in stiffening device 2200m in FIG. 20M. In FIG. 20N, stiffening device 2200n is similar to stiffening device 2200b and includes an inverted bladder layer 2221b (or double-layer bladder), i.e., a pressure gap 2212b surrounded by a compressible layer including bladder layer 2221b with one side abutting stiffening layer 2205b and one side abutting innermost layer 2215b, which includes second stiffening layer 2291. When pressure is supplied to pressure gap 2212b (inside two sides of bladder layer 2221b), bladder layer 2221b can expand both against innermost layer 2215b and internal stiffening layer 2291, and against stiffening layer 2209b (and then be pressed against outermost layer 2201b).

[0135]

[0176] Generally, torsionally stiffening layers may be integrated into flexible tubing, such as the inner and / or outer layers (tubes) of any of the apparatus (devices and systems) described herein. For example, FIG. 17A shows an example of a tubular structure (e.g., an internally coiled tubing) configured to include a torsionally stiffening layer. FIG. 17A shows a cross section of the tubing, configured as a flexible internally coiled tubing 1609. In this example, the flexible tubing includes a first coil wire 1606, shown as a flat wire (or ribbon) helically wound around the tubing on its exposed inner surface. Radially outward from the flat wire is a torsionally stiffening braid 1608 attached at discrete locations (attachment points) 1612 to the outer surface of the flat wire coil 1606. A flexible material (e.g., a polymer coating or laminated elastomer) may be applied over the torsionally stiffening braid and / or between the torsionally stiffening braid and the flat wire. In this example, the flat wires may be left exposed but covered with a flexible polymeric material.

[0136]

[0177] The twisted braid may include multiple filaments. The twisted braid may have a braid angle greater than about 40 degrees relative to the longitudinal axis of the device (e.g., 40 degrees or greater, 45 degrees or greater, 50 degrees or greater, 55 degrees or greater, etc.). The twisted braid may be formed from a polymeric or metallic material.

[0137]

[0178] In any of these devices, the first coil wire and the twisted braid may be bonded to each other at discrete regions along the length of the flexible inner tube. For example, the first coil wire and the twisted braid may be bonded to each other every 30 to 720 degrees of the helically wound coil wire (e.g., every 60 to 720 degrees, every 90 to 720 degrees, every 180 to 720 degrees, every 270 to 720 degrees, every 1 to 2 turns, every 1 to 5 turns, etc.).

[0138]

[0179] In any of these examples, the first coil wire and / or the twisted braid may be at least partially encapsulated within a material (e.g., an elastomeric material). For example, the twisted braid may be at least partially encapsulated within a polymeric material. FIG. 17B shows another example of a cross section of an internal coil wound tube (ICWT) having a torsion stiffening layer. In this example, the tube includes a helically wound flat wire coil 1706 as shown in FIG. 17A, which may be one or more flat wire coils, e.g., two coils. The flat wire coil 1706 is connected to the twisted braid (twisted stiffening braid) 1708 at discrete attachment points 1712 on the outside of the flat wire coil 1706. As mentioned above, the twisted braid may include multiple filaments per bobbin to be applied around the tube with a relatively high coverage. In FIG. 17B, 10 parallel braided wires are shown. In FIG. 17B, the device also includes an encapsulating material 1718, which may be on or around (at least partially) the twisted braid. In some examples, the encapsulating material provides a complete pressure seal around the tube, while in other examples, the tube (e.g., inner or outer tube) containing this material is not sealed. The twisted braid may be directly bonded to the flat wire coil or may be bonded via one or more attachment points 1712. In some examples, the twisted braid is bonded to the flat wire coil via the encapsulating material. This may keep the coil in place and prevent it from floating adjacent to, but not connected to, the flat wire coil and other portions of the device.

[0139]

[0180] The modified inner and / or outer elongated flexible tubes may include a compression layer (e.g., a bladder) as described above. In some instances, an encapsulating material may be used to form a seal or as part of the compression layer. In some cases, little (or no) encapsulation is used.

[0140]

[0181] The same or similar torsion stiffening layer may be incorporated into the outer layer (eg, as an outer coiled tube) of any of the devices described herein.

[0141]

[0182] FIG. 18 schematically illustrates an example of a cross-section of a device including an inner coiled tube, as described above. In this example, the device 1800 includes a reinforced outer layer 1815, which is reinforced with multiple filaments 1822 wound around (or within) the layer. The inner tube (e.g., the inner coiled tube ICWT) 1809 may include one or more reinforcing wires, as shown schematically in FIG. 18. The inner coiled tube 1809 may be adjacent to an inner layer or coating 1856, such as a lubricious coating. A compression layer (e.g., a bladder layer) 1850 may be positioned adjacent to the inner coiled tube 1809, and a stiffening layer (or any of the stiffening layers described herein) may be used or positioned to apply positive pressure to the bladder or between the outer tube and the bladder. FIG. 18 also illustrates a pressure inlet 1855 into the bladder 1850, which connects to a positive pressure source (not shown).

[0142]

[0183] 18 can be rotated about its long axis and track the rotation of the proximal end with the rotation of the distal end due to the torsional stiffness provided by the torsion layer incorporated into the ICWT. In some examples, the outer tube (OCWT) 1815 may additionally or alternatively be configured to include a torsion stiffening layer.

[0143]

[0184] In a nested system, this construct can be incorporated into the mother, the child (daughter), both, or neither the mother nor the child.

[0144] Inner and / or outer layers with different durometer hardness

[0185] Any of the inner or outer layers (tubes) described herein may be configured so that one side of the tube has a higher (harder) durometer than the other side. This is valuable for both high-pressure (positive pressure) and vacuum systems, and for both ICWT and OCWT. For example, in a positive pressure system, an external coiled tube (OCTW) may include an outer portion of the tube (radially far from the centerline of the tube) that has a higher durometer than the inner portion of the tube (not radially far from the centerline). Surprisingly, the inventors have discovered that this configuration provides significant performance improvements. For example, the outer surface has improved abrasion resistance, and the inner surface has a more optimal connection with the stiffening layer, resulting in improved stiffening values. For example, a device may include an inner elongated tube and an outer elongated tube, the outer elongated tube including an inner region, a reinforcing member, and an outer region, the inner region having a lower durometer than the outer region. The outer region may have a durometer hardness of about 70 Shore A to about 80 Shore D, while the inner region may have a durometer hardness between 30 and 90 Shore A on the Shore A scale. The inner layer (tube) may include different durometer hardness regions, but the arrangement relative to the inner and outer regions may be reversed compared to the outer layer. For example, in the case of ICWT, the inner elongated tube may include an inner region, a reinforcing member, and an outer region, where the outer region (radially distant) has a lower durometer hardness than the inner region (not radially distant). For example, the outer region may have a durometer hardness between about 30 and about 90 Shore A on the Shore A scale, while the inner region may have a durometer hardness between about 70 Shore A to 80 Shore D. This configuration achieves the goal of a tougher surface facing outward, while maintaining a softer surface facing inward to improve stiffening when a stiffening layer is pressed against this surface (e.g., improving performance for devices sliding on its inner diameter).

[0145]

[0186] FIG. 19 shows an example cross-sectional view of an outer layer configured as a portion of an outer elongated tube, e.g., an outer coiled tube 1915, having regions of different durometer hardness as described above. In FIG. 19, the outer layer includes a first (e.g., outer) region 1947 over a second (e.g., inner) region 1945. The second (e.g., inner) region 1945 has a lower durometer hardness than the first (e.g., outer) region 1947 of the outer elongated tube. In this example, a stiffening layer between the inner and outer elongated tubes is configured to be punched into the lower durometer (e.g., softer) second region of the outer elongated tube. A stiffening layer (not shown in FIG. 19) contacts the second inner region of the outer elongated tube and may be slightly softer. Applying pressure (e.g., positive pressure) enhances stiffening. The outer layer 1915 also includes a reinforcing member 1949, as described above. In some examples, the outer layer may also include a torsion stiffening layer (not shown in FIG. 19 ). The outer region (radially distant) 1947 and the inner region (not radially distant) 1945 may have different thicknesses or the same thickness. The region between the inner and outer thicknesses may have the same durometer as either the inner region 1945 or the outer region 1947, or a different durometer from either of them.

[0146]

[0187] 20A-20N schematically illustrate different cross-sectional configurations of the rigidizable devices described herein. The drawings are not to scale. Each of these typically includes a stiffening layer, which may be any of the stiffening layers described herein. These different examples illustrate different configurations for use with any of the features or methods described herein, including applying pressure to the stiffening layer in different directions, such as applying positive pressure to push the stiffening layer outward or applying positive pressure to push the stiffening layer inward. For example, FIG. 20A illustrates a stiffening device 2200a including an innermost layer 2215a, a pressure gap 2212a, a compressible layer (e.g., configured as a bladder layer) 2221a sealed to the outermost layer 2201a, a stiffening layer 2209a, and an outer retention layer 2201a. The stiffening device 2200a may further include end caps 2292a at its proximal and distal ends for sealing pressure therein. When pressure is supplied to pressure gap 2212a via inlet 2293a, bladder layer 2221a is forced against stiffening layer 2209a, which in turn is forced against outermost layer 2201a, preventing the stiffening layer from moving (e.g., in some instances, preventing sliding movement of the filaments of the stiffening layer relative to each other).

[0147]

[0188] Referring to FIG. 20H, stiffening device 2200j is similar to stiffening device 2200a, except that it includes a slipping layer 2213j and a stiffening layer 2298j. Layer 2213j is a slipping layer as described herein and can include, for example, a coating or powder. Layer 2298j, like layers 2201j and 2215j, can be a stiffening layer including reinforcing elements 2250z. The additional stiffening layer 2298j can cooperate with inner layer 2215j. For example, the two layers 2215j and 2298j can easily slide past each other (via slipping layer 2213j) in the flexible configuration and adhere to each other to form a stiffened composite structure in the rigid configuration (i.e., when pressure is applied). This layer can be a torsion stiffening layer. Layer 2298j may be a high durometer elastomeric rubber, such as TPU or TPE, with a durometer of 60A, 70A, 80A, or 90A or greater. When the tube is in a flexible state, layers 2215j and 2298j may easily shear or move relative to one another (e.g., due to slip layer 2213j) such that the system is less flexible than if the layers were bonded together. When the tube is in a rigid state (e.g., when pressure is applied), layers 2215j, 2298j, and 2213j may lock together and act like a single bonded layer to resist collapse of the walls of stiffening device 2200j. As with other examples, stiffening layer 2205j can press against outer layer 2201j when pressure is supplied to gap 2212j to stiffen device 2200j.

[0148]

[0189] 20B, stiffening device 2200b is similar to stiffening device 2200a, except that pressure gap 2212b is surrounded by a compressible layer including an inverted bladder layer 2221b (or double-layer bladder), i.e., bladder layer 2221b is surrounded with one side adjacent to stiffening layer 2205b and one side adjacent to innermost layer 2215b. When pressure is supplied to pressure gap 2212b (inside the two sides of bladder layer 2221b), bladder layer 2221b can expand against both innermost layer 2215b and stiffening layer 2209b (which can then press against outermost layer 2201b). In other examples, the device can include a double braid, e.g., one outer layer (2205b) and one inner layer (not shown), which can press against 2215b as pressure is applied. The braid may be one continuous braid (e.g., an everted braided material) or two separate braids. If one continuous braid, it may have a continuous pitch throughout or a different pitch, e.g., different outer and inner portions, or different proximal and distal portions.

[0149]

[0190] 20C, stiffening device 2200c is similar to stiffening device 2200a, except that bladder layer 2221c is sealed to innermost layer 2215c rather than outermost layer 2201c. When pressure is supplied to pressure gap 2212c via inlet 2293c, the compressible layer (e.g., bladder layer 2221c) is forced against stiffening layer 2209c, which in turn is forced against outermost layer 2201c.

[0150]

[0191] FIG. 20G is similar to FIG. 20C, but the compressive layer pushes the stiffening layer inward against the ICWT instead of outward against the OCWT.

[0151]

[0192] 20D, stiffening device 2200d is similar to stiffening device 2200b, except that innermost layer 2215d is a spring element rather than a coiled tube. Because the pressure is on the everted bladder layer 2221d, inner layer 2215d does not need to seal itself.

[0152]

[0193] Referring to FIG. 20E, stiffening device 2200e is similar to stiffening device 2200a, except that innermost layer 2215a is sealed at both the proximal and distal ends and is replaced by an inner payload 2294e that can contain multiple lumens (e.g., working channel 2291e, pressure channel 2292e, and rinse channel 2293e) therein.

[0153]

[0194] Referring to FIG. 20F, stiffening device 2200f is similar to stiffening device 2200a, except that stiffening layer 2209f is inside pressure gap 2212f and a compression layer (e.g., bladder layer 2221f) such that pressure supplied to pressure gap 2212f causes bladder layer 2221f to push stiffening layer 2209f inward, which in turn pushes against innermost layer 2215f.

[0154]

[0195] Referring to FIG. 20I, stiffening device 2200k is similar to stiffening device 2200a, except that annular rings 2219k, comprising, for example, fibers and adhesive, are positioned around each end of stiffening layer 2209k and bladder layer 2221k to attach compression (e.g., bladder) layer 2221k to innermost layer 2215k (thereby maintaining pressure within pressure gap 2212k when pressure is supplied through inlet 2293k). Annular ring 2219k may comprise, for example, high-strength fibers such as Kevlar™ or Dyneema™. Furthermore, the adhesive may be, for example, cyanoacrylate. In some examples, adhesive may also be located at the end between innermost layer 2215k and bladder layer 2221k to include an inlet tube. FIG. 20I also shows secondary inlet 2282. This feature may be active or passive. This feature may be added to any of the other embodiments.

[0155]

[0196] FIG. 20J shows a rigidization device 2200g with a gap inlet 2293g and a vent inlet 2223g. The inlet 2293g connects to a pressure gap 2212g (via pressure line 2294g). The inlet 2223g connects to a gap 2206g around the rigidization layer 2209g (between the bladder 2221g and the outermost layer 2201g). The device 2200g can be rigidized in one or more different configurations. In a first rigidization configuration, pressure can be applied to the inlet 2293g while the vent inlet 2223g can be open or vented to atmospheric pressure. Thus, pressure supplied to the pressure gap 2212g through the inlet 2293g can press the rigidization layer 2209g against the outermost layer 2201g, which can then push the air in the gap 2206g out through the vent inlet 2223g. Allowing air to escape through the vent inlet 2223g allows for a tighter mechanical fit between the rigidizing layer 2209g and the outer layer 2201g, thereby enhancing the rigidity of the device 2200g. In the second rigidification configuration, pressure can be applied to the inlet 2293g and a vacuum can be applied to the vent inlet 2223g. This makes the rigidification device 2200g even more rigid than in the first configuration, as the vacuum can help move the rigidizing layer 2209g toward the outer layer 2201g. This also removes mass that would otherwise be unable to escape into the body if the device were to exhibit structural failure during use. The device 2200g can similarly be made flexible in one or more different configurations. In the first flexible configuration, both the inlet 2293g and the vent inlet 2223g can be open to atmospheric pressure. This relaxes the stiffening layer 2209g relative to the outer layer 2201g, allowing the stiffening layer 2209g to move freely relative to the outer layer 2201g, making the stiffening device 2200g flexible. In the second flexible configuration, a low pressure (e.g., 5-10% above atmospheric pressure) can be supplied to both the inlet 2293g and the vent inlet 2223g. This can cause the outermost layer 2201g and the innermost layer 2215g to separate slightly, providing additional area for the stiffening layer 2209g to move freely. As a result, the stiffening device 2200g is more flexible than in the first stiffening configuration.Additionally, by supplying a low pressure above atmospheric pressure in the flexible configuration, the stiffening device 2200g can be introduced into a body of very small diameter (e.g., such that the pressure gap 2212g is essentially zero), and then low pressure can be supplied to both the inlet 2293g and the vent inlet 2223g to slightly expand the pressure gap 2212g and provide more room for the stiffening layer 2209g to move freely.

[0156]

[0197] FIG. 20K shows stiffening device 2200h with bellows portion 2243h connected to pressure line 2294h. Pressure gap 2212h, pressure line 2294h, and bellows portion 2243h may all be configured to be filled with a sealed pressure transmission medium, such as distilled water, saline, or oil. The pressure transmission medium may be a radiopaque fluid, which may advantageously more clearly show the stiffening device in fluoroscopic procedures. The pressure transmission medium may be added to the stiffening device immediately prior to use and / or when the device is being manufactured. In use, actuator 2288h is actuated to compress bellows portion 2243h, reducing the volume of pressure medium within bellows portion 2243h that flows through pressure line 2294h and into pressure gap 2212h, causing an increase in pressure in pressure gap 2212h and movement of stiffening layer 2209h relative to outer layer 2201h. Vent inlet 2223h can be open to the atmosphere to allow gas to escape from space 2206h around stiffening layer 2209h. Additionally, reversing the action of actuator 2288h reduces the pressure in pressure gap 2212h as the pressure medium returns to bellows 2243h. Actuator 2288h can be, for example, a solenoid, a voice coil, a lead screw, a valve, or a rotating cam. In some examples, pinching or flattening pressure line 2294h can increase the pressure in pressure gap 2212h rather than using bellows 2243h.

[0157]

[0198] FIG. 20L shows rigidization device 2200i including sumps 2230i and 2228i, respectively. Sumps 2230i and 2228i may contain a fluid medium, such as water, and a gaseous medium, such as air. Pressure, vacuum, or a combination thereof may be applied to inlets 2293i, 2223i. Using the sump configuration shown means that there is no air or gas within the rigidization device, regardless of the pressurization state (high pressure, vacuum, or atmospheric pressure) of each gap 2206i or 2212i. In the event of a gap leak during a procedure, only the fluid medium will enter the patient. This protects the patient from gas (e.g., air) embolism.

[0158] Symptoms and Use

[0199] 21 illustrates some of the areas in which apparatus (devices, systems) are used. For example, catheters, sheaths, scopes (e.g., endoscopes), wires, overtubes, cannulas, trocars, or laparoscopic instruments may be used at any of these locations, and / or nested pair devices (one or more of which may be rigidified) may be used. For example, any of the apparatuses described herein may be used in the neurovasculature (e.g., aortic arch, subclavian, carotid, vertebral, skull base, posterior cerebral artery, circle of Willis, middle cerebral artery, anterior cerebral artery, etc.), upper gastrointestinal tract (e.g., oral esophagus, stomach, pylorus, bile duct, and pancreatic duct), small intestinal tract (e.g., small intestine, duodenum, jejunum, iliac, etc.), lower gastrointestinal tract (rectum, colonic region, e.g., sigmoid colon, descending colon, transverse colon, ascending colon, cecum, ileocecal valve, etc.), urinary tract (urethra, bladder, kidneys, ureters, etc.). ), peripheral vasculature (e.g., femoral, iliac, mesenteric, lumbar, renal, celiac, hepatic, thoracic, etc.), cardiac region (e.g., aorta, right coronary artery, left coronary artery, etc.), left heart (e.g., aorta, aortic valve, left ventricle, etc.), right heart (vena cava, right atrium, left atrium, mitral valve, coronary sinus, tricuspid valve, right ventricle, pulmonary valve, pulmonary vasculature, etc.), and / or right pulmonary region (e.g., mouth, larynx, trachea, bronchial tree, lobes of lung, etc.).

[0159]

[0200] Generally, any of the devices (and methods of using them) described herein may be used with or as part of catheters, endoscopes (including, but not limited to, colonoscopes, bronchoscopes, colposcopes, cystoscopes, esophagoscopes, gastroscopes, laparoscopes, thoracoscopes, enteroscopes, etc.), overtubes, etc. These devices and methods may be used with robotic systems, including robotically controlled endoscopes. The robotic systems are robotically manipulated and / or robotically advanced. In some examples, the robotic system may control the movement (e.g., advancement, retraction, and / or actuation) of one or more tools used within the outer working channel, including any of the tools or tool pairs described herein. Any of the devices described herein may be used with robotic systems, including robotic endoscopic systems.

[0160] robotic device

[0201] As mentioned above, the stiffening devices described herein may be configured for use as part of a robotic system or with a robotic device. In some examples, the stiffening device may be configured as a robotically controlled outer tubular member, for example, as a robotically controlled overtube and / or endoscope assembly. FIG. 22 shows an exemplary apparatus 3100 including a stiffening device configured as an overtube 3112, and the system may optionally include an inner endoscope 3110. The overtube and inner endoscope may be robotically controlled or manipulated (e.g., manipulated, moved, rotated, etc., in some examples, including stiffening) separately or collectively. The overtube and inner endoscope may be configured as illustrated in any of the examples above and may have the same overall structure or may be of different structures. As shown in FIG. 22 , the outer overtube 3112 and inner endoscope 3110 may be terminated together into a common structure, such as a cassette 3157. The outer overtube 3100 may be movable relative to the endoscope 3110 by rotation of a driver attached to the cassette 3157. The system may include actuators 3171a, 3171b connected to cables 3163a, b, respectively, to manipulate (e.g., bend or deflect) the tip of the endoscope 3110 (and / or outer overtube 3112). Other manipulation mechanisms (e.g., pneumatic, hydraulic, shape memory alloy, electro-active polymers (EAP), motors, etc.) are also possible. In any variation of the endoscope and / or overtube configured to stiffen when pressure is applied, the cassette 3157 may further include bellows portions 3103a, 3103b connected to the pressure gap of the endoscope 3110 and the overtube 3112, respectively, to drive fluid through pressure line 3105z. As shown in this example, the cassette 3157 may include eccentric cams 3174a, b for controlling the bellows portions 3103a, b. Alternatively, one or more linear actuators may be configured to actuate the bellows portions.As another alternative, the device may be stiffened and de-rigidified by one or more pumps or pressure sources (eg, via pressure line 3105z).

[0161]

[0202] It should be recognized that all combinations of the above concepts and additional concepts discussed in more detail below (provided those concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein and may be used to achieve the advantages described herein.

[0162]

[0203] The process parameters and order of steps described and / or illustrated herein are provided by way of example only and can be varied as desired. For example, although the steps illustrated and / or described herein may be shown or described in a particular order, these steps do not necessarily have to occur in the order illustrated or described. The various exemplary methods described and / or illustrated herein may omit one or more of the steps described or illustrated herein or may include additional steps in addition to those disclosed.

[0163]

[0204] Any of the methods described herein (including user interfaces) 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 executable by a processor (e.g., a computer, a tablet, a smartphone, etc.), which instructions, when executed by the processor, cause the controlling processor to perform any of the steps, including, but not limited to, displaying, communicating with a user, analyzing, modifying parameters (including timing, frequency, intensity, etc.), making decisions, alerting, etc. 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 that stores a set of instructions for the processes of the method.

[0164]

[0205] When a feature or element is referred to herein as being "on" another feature or element, it may be directly on the other feature or element, or there may be intervening features and / or elements. 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. Also, when a feature or element is referred to as being "connected," "attached," or "coupled" to another feature or element, it is understood that it may be directly connected, attached, or coupled to the other feature or element, or that there may be intervening features or elements 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 illustrated with respect to one embodiment, features and elements so described or illustrated may be applicable to other embodiments. Those skilled in the art will also recognize that a reference to a structure or feature being disposed "adjacent" to another feature may have portions that overlap or underlie the adjacent feature.

[0165]

[0206] The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the present invention. For example, as used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly dictates otherwise. It will be further understood that the words "comprises" and / or "comprising," when used herein, 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 word "and / or" includes any and all combinations of one or more of the associated listed items, but may also be omitted.

[0166]

[0207] Spatially relative terms such as "below," "under," "lower," "above," and "upper" are used herein for convenience of description to describe the relationship of one element or feature shown in a figure to another element or feature. It will be understood that 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 the device in the figures is inverted, elements described as being "below" or "below" other elements or features would be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or to other orientations), and the spatially relative descriptors used herein will be interpreted accordingly. Similarly, the terms "upward," "downward," "vertical," "horizontal," and the like are used herein for descriptive purposes only, unless specifically indicated otherwise.

[0167]

[0208] 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 dictates otherwise. These terms may be used to distinguish one feature / element from another. Thus, a first feature / element described below could also be referred to as a second feature / element, and similarly, a second feature / element described below could also be referred to as a first feature / element, without departing from the teachings of the present invention.

[0168]

[0209] Generally, any apparatus and methods described herein should be understood to be inclusive, although all or a subset of the components and / or steps may alternatively be exclusive, and may be expressed as "consisting of" or alternatively "consisting essentially of" various components, steps, sub-components or sub-steps.

[0169]

[0210] As used in this specification and claims, including in the examples, and unless expressly specified otherwise, all numerical values ​​may be read as if preceded by the word "about" or "approximately," even if the word does not explicitly appear. The expressions "about" or "approximately" are sometimes used when describing a size and / or location to indicate that the stated value and / or location is within a reasonable expected range of values ​​and / or locations. For example, a numerical 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. Also, a given numerical value herein should be understood to include about or approximately that value unless the context dictates otherwise. For example, if the value "10" is disclosed, then "about 10" is also disclosed. Any numerical ranges set forth herein are intended to include all subranges subsumed therein. It is also understood that when a value is disclosed as being "less than or equal to" a certain value, "greater than or equal to that value" and possible ranges between those values ​​are also disclosed, as appropriately understood by one of ordinary skill in the art. For example, if a value "X" is disclosed, "less than or equal to X" as well as "greater than or equal to X" (e.g., where X is a numeric value) are also disclosed. It is also understood that throughout this 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, when a specific data point "10" and a specific data point "15" are disclosed, it is understood that greater than 10 and 15, greater than or equal to 10 and 15, less than 10 and 15, less than or equal to 10 and 15, and equal to 10 and 15, as well as between 10 and 15, are considered to be disclosed. It is also understood that each unit between two specified units is disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0170]

[0211] While various exemplary embodiments have been described above, numerous modifications may be made to the various embodiments without departing from the scope of the invention as set forth in the claims. For example, the order in which various described method steps are performed may often be changed in alternative embodiments, and in other alternative embodiments, one or more method steps may be omitted entirely. Optional features of the various device and system embodiments may be included in some embodiments and not in other embodiments. Accordingly, the foregoing description has been made primarily for purposes of illustration and should not be construed as limiting the scope of the invention, which is set forth in the claims.

[0171]

[0212] The examples and illustrations contained herein illustrate, by way of illustration and not limitation, specific embodiments in which the subject matter may be practiced. As noted above, other embodiments may be utilized and derived therefrom, and structural and logical substitutions and changes may be made without departing from the scope of the present disclosure. Such embodiments of the inventive subject matter may be referred to herein individually or collectively under the term "invention" for mere convenience and without any intention of intentionally limiting the scope of the present application to any single invention or inventive concept if one or more are actually disclosed. Thus, while specific embodiments have been illustrated and described herein, any arrangements which are expected to achieve the same purpose may be substituted for the specific embodiments shown. The present disclosure is intended to cover all modifications and variations of the various embodiments. Combinations of the above embodiments and other embodiments not specifically described herein will be apparent to those skilled in the art upon reviewing the above description.

Claims

1. 1. An elongated stiffening device comprising: An inner elongated tube, an outer elongated tube including an inner region, a reinforcing member, and an outer region, the inner region having a durometer hardness lower than a durometer hardness of the outer region; a stiffening layer; and an inlet configured to provide a positive pressure between the inner elongate tube and the outer elongate tube; a compression layer configured to compress the stiffening layer against the interior region of the outer elongate tube when positive pressure is applied through the inlet, wherein the stiffening device is configured to change between a rigid state and a flexible state upon application or release of the positive pressure.

2. 10. The device of claim 1, wherein the inner region of the outer elongate tube has a durometer hardness of between 30 and 90 Shore A on the Shore A scale.

3. 3. The device of claim 1 or 2, wherein the outer region has a durometer hardness of between 70A on the Shore A scale and 80D on the Shore D scale.

4. The device of claim 1 , wherein the reinforcing member comprises a wound coil.

5. The device of claim 1 , wherein the wound coil is stacked between the inner region and the outer region.

6. The device of claim 1 , wherein the compression layer is configured to compress the stiffening layer against the outer elongate tube when positive pressure is applied through the inlet.

7. 7. The device of claim 1, wherein the stiffening layer comprises a plurality of filament lengths configured to cross over and under each other and shear relative to each other.

8. The device of claim 1 , wherein the compressible layer comprises an elastomeric layer.

9. The device of claim 1 , wherein the compressible layer comprises a bladder.

10. 1. An elongated stiffening device comprising: an outer elongated tube; an inner elongated tube including a radially distal first region, a reinforcing member, and a non-radially distal second region, the first radially distal region having a durometer hardness lower than a durometer hardness of the non-radially distal second region; a stiffening layer; and an inlet configured to provide a positive pressure between the inner elongate tube and the outer elongate tube; a compression layer configured to compress the stiffening layer against the radially distal first region of the inner elongate tube when pressure is applied through the inlet, wherein the stiffening device is configured to change between a rigid state and a flexible state upon application or release of the positive pressure.

11. 1. An elongated stiffening device comprising: an outer elongated tube including a radially distant first region, a reinforcing member, and a non-radially distant second region, the non-radially distant second region having a durometer hardness lower than a durometer hardness of the radially distant first region; an inner elongated tube including a radially distant first region, a reinforcing member, and a non-radially distant second region, the radially distant first region having a durometer hardness lower than a durometer hardness of the non-radially distant second region; a stiffening layer; and an inlet configured to provide a negative pressure between the inner elongate tube and the outer elongate tube; an outer tube configured to press the stiffening layer against either the radially closer second region of the outer elongate tube or the radially farther first region of the inner elongate tube when pressure is applied through the inlet, wherein the stiffening device is configured to change between a rigid state and a flexible state upon application or release of the negative pressure.

12. 12. The device of claim 10 or 11, wherein the radially distal first region of the inner elongate tube has a durometer hardness of between 30 and 90 Shore A on the Shore A scale.

13. 13. The device of claim 10, wherein the first radially distal region of the inner elongate tube has a durometer hardness of between 70A on the Shore A scale and 80D on the Shore D scale.

14. 12. The device of claim 11, wherein the second radially distant region of the outer elongate tube has a durometer hardness of between 30 and 90 Shore A on the Shore A scale.

15. 15. The device of claim 14, wherein the radially distal first region of the outer elongate tube has a durometer hardness of between 70A on the Shore A scale and 80D on the Shore D scale.

16. 16. The device of claim 10, wherein the reinforcing member comprises a wound coil.

17. 17. The device of claim 16, wherein the wound coil is stacked between the inner region and the outer region.

18. 18. The device of claim 10, wherein the stiffening layer comprises a plurality of filament lengths configured to cross over and under each other and shear relative to each other.

19. 19. The device of any of claims 10 to 18, wherein the outer elongate tube comprises an elastomeric layer.

20. 1. A stiffening device comprising: an elongated flexible tube; a stiffening layer including a knitted structure; an inlet configured to attach to a pressure source; a compression layer configured to be pressed against the stiffening layer by a pressure differential from the inlet; The stiffening device is configured to change between a rigid state and a flexible state upon application or release of pressure.

21. The device of claim 20 , wherein the braided structure comprises a braided tube.

22. 22. The device of claim 20 or 21, wherein the braid is configured such that the wale direction of the braid extends along the longitudinal axis of the flexible tube.

23. 23. The device of any of claims 20 to 22, wherein the braid is configured such that the wale direction of the braid is perpendicular to the longitudinal axis of the flexible tube.

24. 24. The device of any of claims 20 to 23, wherein the knitted structure has an average loop length that is greater than two times its average loop width.

25. 25. The device of any of claims 20 to 24, wherein the braided structure comprises braided fiber bundles.

26. 26. The device of any of claims 20 to 25, further comprising a reinforced outer layer.

27. 27. The device of any of claims 20 to 26, wherein the elongated flexible tube comprises a coil-reinforced tube.

28. 28. The device of any of claims 20 to 27, wherein the inlet is coupled to a proximal end of the elongate flexible tube.

29. 29. The device of any of claims 20 to 28, wherein the inlet is configured to be attached to a positive pressure source, and further wherein the compressible layer is configured to be forced against the stiffening layer when positive pressure is applied through the inlet.

30. 30. The device of any of claims 20 to 29, wherein the inlet is configured to be attached to a negative pressure source, and further wherein the compressible layer is configured to be pressed against the stiffening layer when negative pressure is applied through the inlet.

31. 31. The device of any of claims 20 to 30, wherein the compressible layer comprises an elastomeric layer.

32. 32. The device of any of claims 20 to 31, wherein the compressible layer comprises a bladder.

33. 33. The device of any of claims 20 to 32, wherein the stiffening device is configured to have a rigid configuration when positive or negative pressure is applied through the inlet and a flexible configuration when no pressure is applied through the inlet.

34. 1. A stiffening device comprising: an elongated flexible tube; a stiffening layer including an array of filament lengths configured to cross over and under each other and move relative to each other; an inlet configured to attach to a positive pressure source; a compression layer configured to be pressed against the stiffening layer by a pressure differential from the inlet to stiffen the stiffening layer; The stiffening device is configured to change between a rigid state and a flexible state upon application or release of pressure.

35. 35. The device of claim 34, wherein the array of filament lengths comprises a plurality of discrete filaments.

36. 36. The device of claim 35, wherein at least some of the filament lengths in the array of filament lengths are part of the same filament.

37. 37. The device of any of claims 34-36, wherein the array of filament lengths comprises woven, braided, knitted, chopped filaments, or randomly oriented filaments.

38. 38. The device of any of claims 34 to 37, wherein the array of filament lengths comprises one or more wires.

39. 39. The device of any of claims 34 to 38, further comprising a reinforced outer layer.

40. 40. The device of any of claims 34 to 39, wherein the elongated flexible tube comprises a coil-reinforced tube.

41. 41. The device of any of claims 34 to 40, wherein the inlet is coupled to a proximal end of the elongate flexible tube.

42. 42. The device of any of claims 34 to 41, wherein the inlet is configured to be attached to a positive pressure source, and further wherein the compressible layer is configured to be pressed against the stiffening layer when positive pressure is applied through the inlet.

43. 43. The device of any of claims 34 to 42, wherein the inlet is configured to be attached to a negative pressure source, and further wherein the compressible layer is configured to be pressed against the stiffening layer when negative pressure is applied through the inlet.

44. 44. The device of any of claims 34 to 43, wherein the compressible layer comprises an elastomeric layer.

45. 45. The device of any of claims 34 to 44, wherein the compressible layer comprises a bladder.

46. 46. ​​The device of any of claims 34 to 45, wherein the stiffening device is configured to have a rigid configuration when positive or negative pressure is applied through the inlet and a flexible configuration when no pressure is applied through the inlet.

47. 1. A stiffening device comprising: a flexible inner tube reinforced to withstand radial compressive loads; a flexible outer tube reinforced to withstand radial tensile loads; a stiffening layer between the inner and outer tubes including a plurality of filament lengths configured to cross over and under each other and move relative to each other; a compressible layer configured to deform into the stiffening layer when a positive pressure is applied to the compressible layer; A stiffening device, wherein application of pressure limits movement of the plurality of filament lengths, thereby increasing stiffening.

48. 48. The device of claim 47, wherein the deformable compressible layer comprises a bladder.

49. 49. The device of claim 47 or 48, wherein the stiffening layer is between the flexible outer tube and the compressible layer, the compressible layer being configured to compress the stiffening layer into the outer tube when a positive pressure is applied to the compressible layer.

50. 50. The device of any of claims 47 to 49, wherein the stiffening layer is between the flexible inner tube and the compressible layer, the compressible layer being configured to compress the stiffening layer into the inner tube when a positive pressure is applied to the compressible layer.

51. 51. The device of any of claims 47 to 50, wherein the deformable compressible layer comprises an elastomeric layer.

52. 52. The device of any of claims 47-51, wherein the flexible outer tube includes a coil reinforcement layer.

53. 53. The device of any of claims 47 to 52, wherein the flexible inner tube includes a coil reinforcement layer.

54. 54. The device of any of claims 47 to 53, wherein the array of filament lengths comprises a plurality of filaments.

55. 55. The device of any of claims 47-54, wherein the array of filament lengths comprises woven, braided, knitted, chopped filaments, or randomly oriented filaments.

56. 56. The device of any of claims 47 to 55, wherein the array of filament lengths comprises one or more wires.

57. 57. The device of any of claims 47-56, further comprising an inlet in fluid communication with the compressible layer and configured to couple to a source of positive pressure.

58. 58. The device of any of claims 47 to 57, wherein the inlet is coupled to a proximal end of a flexible elongate tube.

59. 59. The device of any of claims 47 to 58, wherein the stiffening device is configured to have a rigid configuration when positive pressure is applied through the inlet and a flexible configuration when no pressure is applied through the inlet.

60. 1. A stiffening device comprising: a flexible outer tube; a flexible inner tube; a stiffening layer including a plurality of overlapping members between the inner tube and the outer tube; an inlet configured to attach to a positive pressure source; a compression layer between the outer tube and the inner tube configured to press against the stiffening layer when positive pressure is applied through the inlet to compress and stiffen the stiffening layer.

61. 61. The device of claim 60, wherein the overlapping members comprise a plurality of overlapping scales or plates.

62. 62. The device of claim 60 or 61, wherein the overlapping members are radially and longitudinally disposed between the inner tube and the outer tube.

63. 63. The device of any of claims 60 to 62, wherein the overlapping member comprises two or more layers of overlapping member.

64. 64. The device of any of claims 60 to 63, wherein the plurality of overlapping members includes a plurality of engagement features between the overlapping members.

65. 65. The device of any of claims 60 to 64, wherein the plurality of overlapping members interlock along the length of the stiffening layer.

66. 66. The device of any of claims 60 to 65, wherein the plurality of overlapping members have frictionally engineered surfaces.

67. 67. The device of any of claims 60 to 66, wherein the compressible layer comprises a bladder.

68. 68. The device of any of claims 60 to 67, wherein the compressible layer comprises an elastomeric layer.

69. 69. The device of any of claims 60-68, wherein the flexible outer tube includes a coil reinforcement layer.

70. 70. The device of any of claims 60 to 69, wherein the flexible inner tube includes a coil reinforcement layer.

71. 71. The device of any of claims 60 to 70, wherein the inlet is coupled to a proximal end of a flexible elongate tube.

72. 72. A device according to any of claims 60 to 71, wherein the stiffening device is configured to change between a rigid state and a flexible state upon application or release of pressure.

73. 1. A stiffening device comprising: a flexible outer tube; a flexible inner tube; a stiffening layer including a plurality of overlapping or non-overlapping members arranged side by side in radial and longitudinal directions between the inner tube and the outer tube; an inlet configured to attach to a positive pressure source; a compression layer between the outer tube and the inner tube configured to be pressed against the stiffening layer when positive pressure is applied through the inlet to compress and stiffen the stiffening layer.

74. 74. The device of claim 73, wherein the overlapping or non-overlapping members include a plurality of arms extending from one or more radial mounting portions.

75. 75. The device of claim 73 or 74, wherein the overlapping or non-overlapping members are non-overlapping.

76. 76. The device of claim 73 or 75, wherein the overlapping or non-overlapping members overlap.

77. 77. A device according to any of claims 73 to 76, wherein the overlapping or non-overlapping members comprise two or more rows of overlapping or non-overlapping members.

78. 78. A device according to any one of claims 73 to 77, wherein the member is spirally wound.

79. 79. A device according to any one of claims 73 to 78, wherein the overlapping members are individually attached.

80. 80. A device as claimed in any one of claims 73 to 79, wherein the member is attached to a spine.

81. 81. The device of any of claims 73 to 80, wherein the compressible layer comprises a bladder.

82. 82. The device of any of claims 73 to 81, wherein the compressible layer comprises an elastomeric layer.

83. 83. The device of any of claims 73 to 82, wherein the flexible outer tube includes a coil reinforcement layer.

84. 84. The device of any of claims 73 to 83, wherein the flexible inner tube includes a coil reinforcement layer.

85. 85. The device of any of claims 73 to 84, wherein the inlet is coupled to a proximal end of a flexible elongate tube.

86. 86. A device according to any of claims 73 to 85, wherein the stiffening device is configured to change between a rigid state and a flexible state upon application or release of pressure.

87. 1. A stiffening device comprising: a flexible outer tube; a flexible inner tube; a stiffening layer including a plurality of radial engagement members between the inner tube and the outer tube; an inlet configured to attach to a positive pressure source; a compression layer between the outer tube and the inner tube configured to be pressed against the stiffening layer when positive pressure is applied through the inlet to drive engagement of the radial engagement members.

88. 88. The device of claim 87, wherein the plurality of radial engagement members comprises interlocking members.

89. 88. The device of claim 87, wherein the plurality of radial engagement members comprises a plurality of radial nesting members extending along a length from proximal to distal.

90. 90. A device as described in any one of claims 87 to 89, wherein the plurality of radial engagement members comprises a plurality of radially flexible members.

91. 91. The device of any of claims 87-90, wherein the compressible layer comprises a bladder.

92. 92. The device of any of claims 87 to 91, wherein the compressible layer comprises an elastomeric layer.

93. 93. The device of any of claims 87-92, wherein the flexible outer tube includes a coil reinforcement layer.

94. 94. The device of any of claims 87 to 93, wherein the flexible inner tube includes a coil reinforcement layer.

95. 95. The device of any of claims 87 to 94, wherein the inlet is coupled to a proximal end of a flexible elongate tube.

96. 96. A device according to any of claims 87 to 95, wherein the stiffening device is configured to change between a rigid state and a flexible state upon application or release of pressure.

97. 1. A stiffening device comprising: a flexible outer tube; a flexible inner tube; a stiffening layer between the inner tube and the outer tube, the stiffening layer including a woven layer; an inlet configured to attach to a positive pressure source; a compression layer between the outer tube and the inner tube configured to press against the stiffening layer when positive pressure is applied through the inlet to compress and stiffen the stiffening layer.

98. 98. The device of claim 97, wherein the woven layer includes a plurality of filament lengths configured to cross over and under each other and shear relative to each other.

99. 99. The device of claim 97 or 98, wherein the compression layer is configured to contact the flexible outer layer or the flexible inner layer and conform around the plurality of filament lengths to prevent the plurality of filament lengths from shearing relative to one another when positive pressure is applied through the inlet.

100. 100. The device of any of claims 97-99, wherein the compressible layer comprises a bladder.

101. 101. The device of any of claims 97-100, wherein the compressible layer comprises an elastomeric layer.

102. 102. The device of any of claims 97-101, wherein the flexible outer tube includes a coil reinforcement layer.

103. 103. The device of any of claims 97 to 102, wherein the flexible inner tube includes a coil reinforcement layer.

104. 104. A device according to any of claims 97 to 103, wherein the inlet is coupled to a proximal end of a flexible elongate tube.

105. 105. A device according to any of claims 97 to 104, wherein the stiffening device is configured to change between a rigid state and a flexible state upon application or release of pressure.

106. 1. A nested system comprising: a first stiffening device including a plurality of layers, the first stiffening device configured to be stiffened by applying a pressure differential to drive a compressible layer relative to a knitted stiffening layer forming at least one of the plurality of layers of the first stiffening device; a second stiffening device configured to stiffen, the second stiffening device nested within the first stiffening device; A nested system, wherein the first stiffening device and the second stiffening device are configured to translate relative to each other to stiffen to propagate a shape along the nested system.

107. 107. The system of claim 106, wherein the braided stiffening layer comprises a braided tube.

108. 108. The system of claim 106 or 107, wherein the knitted stiffening layer is configured such that the warp direction of the knitted structure extends along the longitudinal axis of the flexible tube.

109. 109. The system of any of claims 106-108, wherein the knitted stiffening layer is configured such that the warp direction of the knitted structure is perpendicular to the longitudinal axis of the flexible tube.

110. 110. The system of any of claims 106-109, wherein the knitted stiffening layer has an average loop length that is greater than two times its average loop width.

111. 111. The system of any of claims 106-110, wherein the braided stiffening layer comprises braided fiber bundles.

112. 112. The system of any of claims 106-111, wherein the first stiffening device and the second stiffening device each include a continuous curved surface configured to slide smoothly relative to one another.

113. 113. The system of any of claims 106 to 112, wherein the first stiffening device and the second stiffening device each comprise a pressurized coiled tube configured to form a continuous curved surface to slide smoothly relative to one another.

114. 114. The system of any of claims 106 to 113, wherein the compression layer comprises a bladder.

115. 115. The system of any of claims 106-114, wherein at least one of the first stiffening device and the second stiffening device includes a manipulable distal end region including a plurality of links.

116. 116. The system of any of claims 106 to 115, wherein the first stiffening device is configured to be stiffened by application of positive pressure.

117. 117. The system of any of claims 106 to 116, wherein the second stiffening system is configured to nest with the first stiffening device.

118. 118. The system of any of claims 106 to 117, further comprising a controller configured to coordinate alternating stiffening of the first stiffening device and the second stiffening device.

119. 1. A stiffening device comprising: a flexible inner tube configured to provide torsional stiffening, the flexible inner tube including a first coil wire and a twisted braid; a flexible outer tube; a stiffening layer between the inner tube and the outer tube; an inlet configured to attach to a positive pressure source; a compression layer configured to be compressed against the stiffening layer when positive pressure is applied through the inlet; The stiffening device is configured to have a rigid configuration when positive pressure is applied through the inlet and a flexible configuration when positive pressure is not applied through the inlet.

120. 120. The device of claim 119, wherein the first coil wire comprises a flat wire helically wound around a length of the flexible inner tube.

121. 121. The device of claim 119 or 120, wherein the twisted braid comprises multiple filaments.

122. 122. A device as described in any one of claims 119 to 121, wherein the twisted braid has a braid angle greater than 30 degrees.

123. 123. The device of any of claims 119-122, wherein the first coil wire and the twisted braid are bonded to one another at discrete regions along the length of the flexible inner tube.

124. 124. The device of any of claims 119 to 123, wherein the first coil wire and the twisted braid are encapsulated in a material.

125. 125. The device of claim 124, wherein the material is a polymeric material.

126. 1. A nested system comprising: a first stiffening device; and a second stiffening device nested within the first stiffening device; A nested system wherein the second stiffening device is configured to have high torsional stiffness in a non-stiffened configuration so that distal rotational output can be precisely controlled for a given proximal rotational input.

127. 127. The system of claim 126, further comprising a controller configured to maintain the first stiffening device in a stiffened configuration while applying a torque to the second stiffening device.

128. 127. The system of claim 126, wherein the second stiffening device comprises a torsion stiffening braid.

129. 127. The system of claim 126, further comprising a lubricious material between the first stiffening device and the second stiffening device.

130. 127. The system of claim 126, wherein the second stiffening device is configured such that output rotation is within + / - 15% of input rotation.

131. 127. The system of claim 126, wherein the second stiffening device comprises a device described in any of claims 119 to 125.

132. 127. The system of claim 126, further comprising an electronic input device configured to control rotation of the second stiffening device.

133. 133. The system of claim 132, wherein the electronic input device includes an actuator configured to rotate the second stiffening device.

134. 1. A nested system comprising: a first stiffening device including a plurality of layers, the first stiffening device configured to be stiffened by applying a pressure differential to drive a compressible layer relative to a stiffening layer forming at least one of the plurality of layers of the first stiffening device; a second stiffening device configured to stiffen, the second stiffening device nested within the first stiffening device; A nested system, wherein the first stiffening device and the second stiffening device are configured to alternately stiffen in translation relative to each other to propagate a shape.

135. 135. The system of claim 134, wherein the first stiffening device and the second stiffening device each include a continuous curved surface configured to slide smoothly relative to one another.

136. 135. The system of claim 134, wherein the first stiffening device and the second stiffening device each comprise a pressurized coiled tube configured to form a continuous curved surface to slide smoothly relative to one another in both the stiffened and non-rigidified configurations.

137. 135. The system of claim 134, wherein the compression layer comprises a bladder.

138. 135. The system of claim 134, wherein the stiffening layer comprises a plurality of filament lengths configured to cross over and under each other and shear relative to each other.

139. 135. The system of claim 134, wherein the stiffening layer comprises a braided layer.

140. 135. The system of claim 134, wherein the stiffening layer comprises a knitted layer.

141. 135. The system of claim 134, wherein at least one of the first stiffening device and the second stiffening device includes a manipulable distal end region including a plurality of links.

142. 135. The system of claim 134, wherein the first stiffening device is configured to be stiffened by application of positive pressure.

143. 135. The system of claim 134, wherein the second stiffening device is configured to nest within the first stiffening device.

144. 135. The system of claim 134, further comprising a controller configured to coordinate alternating stiffening of the first stiffening device and the second stiffening device.

145. 1. A stiffening device comprising: a flexible inner tube; a flexible outer tube; a stiffening layer between the inner tube and the outer tube, the stiffening layer including a plurality of granules; an inlet configured to attach to a positive pressure source; a compression layer between the inner tube and the outer tube configured to be pressed against the stiffening layer when positive pressure is applied through the inlet to compress and stiffen the stiffening layer.

146. 146. The device of claim 145, wherein the plurality of granules comprises a plurality of irregularly shaped granules.

147. 146. The device of claim 145, wherein the plurality of granules comprises a plurality of regularly shaped granules.

148. 148. The device of any of claims 145 to 147, wherein the compressible layer comprises a bladder.

149. 149. The device of any of claims 145 to 148, wherein the compressible layer comprises an elastomeric layer.

150. 150. A device as described in any one of claims 145 to 149, wherein the flexible outer tube includes a coil reinforcement layer.

151. 151. A device as described in any of claims 145 to 150, wherein the flexible inner tube includes a coil reinforcement layer.

152. 152. A device as described in any of claims 145 to 151, wherein the inner tube or the outer tube is reinforced but not reinforced with a coil.

153. 153. A device according to any of claims 145 to 152, wherein the inlet is coupled to a proximal end of a flexible elongate tube.

154. 154. A device according to any of claims 145 to 153, wherein the stiffening device is configured to change between a rigid state and a flexible state upon application or release of pressure.

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