Deployable flexible overtube

Abstract

A flexible overtube and a method for deploying the overtube are presented, the overtube being configured to guide an endoscope to an in vivo deployment location within a patient's colon. An anchoring balloon may be provided at the distal end of the overtube to secure the overtube in place. The retraction of the flexible overtube and anchoring balloon may take the form of an origami folding pattern or a pattern derived from the stable, inextensible post-buckling pattern of a thin-walled cylinder under axial compression or combined axial-torsion loading. This folding effectively retracts the overtube and balloon into a folding retraction mechanism. Progressive deployment of the flexible overtube's tension may progress from the proximal end to the distal end of the overtube. This retraction provides an ideal method for deploying the flexible overtube and delivering a propulsion and steering mechanism into the patient's colon.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 433,360, filed December 16, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates generally to instruments for use in colonoscopy procedures, and more particularly to the initial deployment and fixation of a flexible overtube within a patient's colon. Once the overtube is deployed and fixed within the patient's colon, it receives and guides a colonoscope into the patient's colon with minimal effort. [Background technology]

[0003] Colonoscopy is the most effective procedure for examining the rectum and colon. Nearly 20 million colonoscopies are performed annually in the United States alone. However, there are several challenges associated with colonoscopy, including pain and discomfort for patients, pain and endoscopy-related injuries for endoscopists and nurses, and prolonged and variable colonoscope insertion times.

[0004] Colonoscopy is a challenging procedure due to looping, which occurs when the colonoscope's flexible insertion tube advances through the flexible and tortuous colon without corresponding advancement of the distal tip, as shown in Figures 1A and 1B. Looping during colonoscope insertion can stretch the colonic mucosa, causing patient pain and the need for sedation, increasing patient risk, recovery time, and procedural costs. Looping also contributes to prolonged and variable insertion times, negatively impacting scheduling and productivity. Colonoscopy also carries a small risk of colonic perforation, which is increased by looping.

[0005] Colonoscopy requires significant training for endoscopists to learn and master. To prevent looping, endoscopists must repeatedly push, pull, twist, and manipulate the colonoscope in awkward positions. Due to the repetitive use of muscles, joints, and tendons, and the awkward, twisted positions required to navigate the difficult bends of the large intestine, gastrointestinal (GI) endoscopists performing colonoscopies are at high risk for endoscopy-related injury (ERI). Several survey-based studies have shown that ERI occurs in up to 37–89% of practicing endoscopists.

[0006] Nurses often need to apply abdominal pressure to prevent colonoscope looping and move sedated patients for gravity assistance during colonoscope insertion. The problem of looping is more severe in obese patients due to a redundant colon, and moving obese sedated patients is more difficult. These factors put nurses at increased risk for repetitive stress injury. Some studies have shown a prevalence of ERI in endoscopy nurses of 85%.

[0007] It would be desirable to provide improved techniques for colonoscope insertion that are less painful for patients, endoscopists, and nurses. It would also be desirable to reduce the skill dependency of colonoscope insertion and reduce both the average insertion time and the variability of insertion time from procedure to procedure. Potential benefits of the devices disclosed herein include enabling a less painful procedure for patients, reducing the risk of endoscopy-related injury for endoscopists and nurses, and shortening procedure time and / or reducing / eliminating the need for sedation. Summary of the Invention

[0008] According to one embodiment of the present disclosure, a deployment device is configured to guide an endoscope to an in vivo deployment position within a patient's colon. The deployment device includes a flexible overtube having a distal end, a proximal end, a folded portion, and an expanded portion. An introducer is fixedly coupled to the proximal end of the flexible overtube, the introducer adapted to be anchored in place near the proximal end of the colon. A delivery element is coupled to the distal end of the flexible overtube, the delivery element including a steering element and a propulsion element, the steering element including a proximal end and a distal end, the distal end of the steering element comprising the distal end of the deployment device when the deployment device is in use. The propulsion element is disposed adjacent to the steering element and exerts an axial force on the steering element to drive the steering element distally relative to the introducer, thereby gradually expanding and deploying the flexible overtube until the distal end of the overtube reaches the deployed position. Deployment of the flexible overtube forms a tubular cavity enclosed by the flexible overtube that extends within the patient's colon from the introducer to a deployment location and is configured to guide the endoscope to the deployment location.

[0009] The deployment device may also include a fixation member attached to the distal end of the flexible overtube to maintain the distal end of the flexible overtube in a deployed position. The fixation member may be an inflated balloon that frictionally engages the inner surface of the colon. The deployment device may also include a containment member that surrounds the folded portion of the overtube and maintains the folded portion of the flexible overtube in a folded configuration. The folded portion of the flexible overtube may include a cylindrical tube-containment folding pattern that includes a stable, inextensible post-buckling pattern of a thin-walled cylinder under axial compression or combined axial-torsional loading. The propulsion element may include a propulsion balloon and a propulsion balloon inflation lumen configured to supply pressurized fluid to the propulsion balloon to inflate the propulsion balloon. The inflated propulsion balloon may form a seal with the inner surface of the flexible overtube.

[0010] The axial force exerted by the propulsion element on the steering element can result from pressurized fluid pumped into a sealed tubular cavity, exerting a pressure force on the proximal surface of the propulsion element. Additionally, the steering element can have a cylinder made of a flexible material and including two or more internal chambers, each of which can be selectively pressurized and depressurized, and selective pressurization of the chambers causes the cylinder to bend in the steering direction. A multi-lumen catheter can also be provided that supplies pressurized fluid to each of the internal chambers, the catheter extending to the introducer and connected to a fluid supply system adapted to control the pressure within the chambers. The fluid supply system of any embodiment can be automated.

[0011] The deployment device can include an insufflation seal member attached to the introducer, the insufflation seal member configured to form a seal between the introducer and the patient's colon. Such a device can also have a colonic insufflation port adjacent to the distal side of the insufflation seal member, the insufflation port configured to deliver pressurized fluid to the patient's colon to insufflate the colon. The fixation member can be attached to a distal end of the flexible overtube, the fixation member being a balloon configured to maintain the distal end of the flexible overtube in the deployed position, and the steering element configured to receive the folded portion of the flexible overtube and the fixation balloon.

[0012] One embodiment provides a method for guiding an endoscope to an in vivo deployment position within a patient's colon. The method includes inserting an introducer into a proximal end of the patient's colon and anchoring the introducer in a stationary position near the proximal end of the colon. A deployment device can be advanced distally into the patient's colon, the deployment device coupled to the introducer by a flexible overtube, a distal end of the flexible overtube coupled to the deployment device, and a proximal end of the flexible overtube coupled to the introducer. The deployment device can include a steering element and a propulsion element, the steering element having a proximal end and a distal end, the distal end of the steering element comprising the distal end of the deployment device when the deployment device is in use. The method may include deploying a flexible overtube, the flexible overtube having a folded portion and an unfolded portion, where unfolding the overtube may include expanding the unfolded portion by unfolding the folded portion until a distal end of a deployment device reaches a deployed position, where unfolding the overtube results from advancing the deployment device, and further, where unfolding the flexible overtube results in a sealed tubular cavity enclosed by the flexible overtube. The method may also include supplying a pressurized fluid to the sealed tubular cavity of the overtube, the pressurized fluid exerting an axial force on a propulsion element of the deployment device to advance the deployment device distally relative to the introducer. The method may also include inserting an endoscope into the proximal end of the flexible overtube and through the sealed tubular cavity to the distal end of the overtube, and thus to the deployed position.

[0013] The method may also include inflating a balloon attached to the distal end of the flexible overtube, whereby the distal end of the flexible overtube frictionally engages the inner surface of the colon and secures the flexible overtube in place relative to the patient's colon, and a steering element may be configured to receive the folded portion of the flexible overtube and the balloon prior to inflation of the balloon.

[0014] The deployment device in the method may also include a deployment balloon, and the method further includes inflating the propulsion balloon, wherein an axial force is exerted on a proximal portion of the inflated propulsion balloon, and forming a seal between the inflated propulsion balloon and an inner surface of the flexible overtube. The steering element may include a flexible cylinder enclosing two or more internal chambers, and the method further includes steering the deployment device by selectively pressurizing and depressurizing the chambers, thereby causing the flexible cylinder to bend in the steering direction. The method may also include forming a seal between the introducer and the patient's colon by inflating a seal member attached to the introducer, and insufflating the patient's colon by delivering pressurized fluid through the insufflation port into the patient's colon distal to the insufflation seal member.

[0015] Further advantages and features of the present disclosure will become apparent from the following detailed description and accompanying drawings. [Brief explanation of the drawings]

[0016] [Figure 1] A-E show examples of colonoscopic looping in the sigmoid and transverse colon.

[0017] [Figure 2A] FIG. 1 is a perspective view of an exemplary guide assembly according to various aspects of the present disclosure.

[0018] [Figure 2B] 2B shows a cross-sectional perspective view of the guide assembly of FIG. 2A.

[0019] [Figure 2C] 2B shows a partial cross-sectional perspective detail view of the guide assembly of FIG. 2A with the anchoring balloon in an inflated state.

[0020] [Figure 2D] 2B shows a partial cross-sectional perspective detail view of the guide assembly of FIG. 2A with the anchoring balloon in a deflated state.

[0021] [Figure 3A] 2A and 2B illustrate an exemplary method of fabricating the overtube and anchoring balloon inflation channel of the guide assembly of FIG. 2A. [Figure 3B] 2A and 2B illustrate an exemplary method of fabricating the overtube and anchoring balloon inflation channel of the guide assembly of FIG. 2A.

[0022] [Figure 4] 2B illustrates an exemplary method of manufacturing and assembling the anchoring balloon of the guide assembly of FIG. 2A.

[0023] [Figure 5A] 10 shows an exemplary origami folding pattern on a flat sheet representing the open cylindrical overtube of the guide assembly.

[0024] [Figure 5B] 2B shows a side perspective view of the guide assembly of FIG. 2A with the overtube in a partially collapsed and stowed position.

[0025] [Figure 5C] 5C shows a cross-sectional perspective view of the partially collapsed overtube of FIG. 5B.

[0026] [Figure 6A] 2B shows a partially transparent perspective view of an exemplary delivery assembly for use with the guide assembly of FIG. 2A.

[0027] [Figure 6B] 6B shows a cross-sectional perspective view of the exemplary delivery assembly of FIG. 6A.

[0028] [Figure 7] 6B shows a cross-sectional perspective view of an exemplary catheter holder of the delivery assembly of FIG. 6A.

[0029] [Figure 8A] 6B shows an enlarged view of the steering mechanism and propulsion balloon of the delivery assembly of FIG. 6A.

[0030] [Figure 8B] 6B shows a simplified diagram of an exemplary steering mechanism of the delivery assembly of FIG. 6A.

[0031] [Figure 9] 1 shows a cross-sectional view of an exemplary catheter.

[0032] [Figure 10] 10 is a graph of an exemplary valve schedule for three steering control valves that control pressure in the steering chambers of the steering mechanism of FIGS. 6A and 9 . FIG.

[0033] [Figure 11] 6B shows a cross-sectional side view of the guide assembly of FIG. 2A coupled to the delivery assembly of FIG. 6A.

[0034] [Figure 12] 6B shows a partially transparent cross-sectional perspective view of the guide assembly of FIG. 2A coupled with the delivery assembly of FIG. 6A.

[0035] [Figure 13] 10A-10C show multiple cross-sectional views of the guide assembly in four deployment states of the flexible overtube.

[0036] [Figure 14] 2B shows a cross-sectional side view of the guide assembly of FIG. 2A in a partially deployed configuration.

[0037] [Figure 15A] FIG. 15A shows an exemplary origami folding pattern applied to fold a planar anchoring balloon into compact storage.

[0038] [Figure 15B]15B and C are perspective and side views, respectively, of an anchoring balloon folded to encompass the distal end of a flexible overtube in a folded orientation using the folding pattern of A. [Figure 15C] 15B and C are perspective and side views, respectively, of an anchoring balloon folded to encompass the distal end of a flexible overtube in a folded orientation using the folding pattern of A.

[0039] [Figure 16] FIG. 16 is a perspective view of the folded anchoring balloon of FIG. 15 positioned over the folded distal end of a partially deployed flexible overtube.

[0040] [Figure 17] AF show exemplary deployment and fixation steps of a deployment device within the colon to facilitate easy insertion of a colonoscope through a guide tube.

[0041] [Figure 18] FIG. 12 is a schematic diagram of an exemplary fluid control system for use with the guide assembly and delivery assembly of FIG.

[0042] [Figure 19A] FIG. 12 is an enlarged perspective side view of the electromagnetic coil 248 shown in FIG.

[0043] [Figure 19B] FIG. 1 is a perspective view of an electromagnetic coil tracking setup according to an embodiment of the present disclosure.

[0044] [Figure 20A] 10 shows a 2D representation of an exemplary display of a device trajectory presented by an EM tracking setup according to an embodiment of the present disclosure.

[0045] [Figure 20B]10 shows a 3D representation of an exemplary display of a device trajectory presented by an EM tracking setup according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0046] Detailed Description

[0047] Reference will now be made in detail to presently preferred embodiments and methods of the present disclosure, including the best mode of carrying out the disclosure currently known to the inventors. The figures are not necessarily to scale. However, it should be understood that the disclosed embodiments are merely examples of the disclosure, which may be embodied in various and alternative forms. Accordingly, the specific details disclosed herein should not be construed as limiting, but rather as exemplary principles for teaching any aspect of the disclosure and / or to those skilled in the art to utilize the disclosure in various ways. Furthermore, the terminology used herein is used only for the purpose of describing particular embodiments of the disclosure and is not intended to be limiting in any way.

[0048] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. For example, reference to an element in the singular is intended to include plural elements.

[0049] Also, as used herein and in the appended claims, the terms "distal" and "proximal" are defined relative to the device / endoscopist, not the patient / colon. Thus, for example, a "distal" element is relatively further from the endoscopist's perspective than a "proximal" element, which is relatively closer to the endoscopist's perspective. The terms "distal" and "proximal" apply to references to the device as well as the colon. As used herein and in the appended claims, the "proximal" colon refers to the anus, and the "distal" colon refers to the cecum, which is the opposite of the medical definitions.

[0050] 11 , deployment device 1000 is configured to receive and guide an endoscope to a deployment location within a living body. The main components of deployment device 1000 include a guide assembly 100 and a delivery assembly 200, each of which is described in further detail below. Guide assembly 100 is positioned within the patient's colon. The guide assembly houses an introducer 150 that may be positioned adjacent to and engage the patient's anus. Delivery assembly 200 houses a multi-lumen catheter 240 that may be delivered into the colon from a catheter holder 250. These components may be removably coupled such that introducer 150 supports guide assembly 100 and acts as a connection between guide assembly 100 and delivery assembly 200.

[0051] 2A-2C illustrate an exemplary guide assembly 100 according to various aspects of the present disclosure. In the illustrated embodiment, the guide assembly 100 includes a flexible overtube 110 and an introducer 150 attached to the proximal end 112 of the flexible overtube 110.

[0052] The flexible overtube 110 can include an annular / donut-shaped anchoring balloon 120 at its distal end 114. An anchoring balloon inflation channel 130 is incorporated alongside the flexible overtube 110 and extends from the proximal end 112 to the distal end 114. The anchoring balloon inflation channel 130 is in fluid communication with an anchoring balloon cavity 128 by an opening 126 and connects to an anchoring balloon inflation port 132 adjacent the proximal end 112 to allow for inflation and deflation of the anchoring balloon 120.

[0053] In some embodiments, the flexible overtube 110 or the fixation balloon 120 comprises thermoplastic polyurethane (TPU), thermoplastic elastomer (TPE), nylon, polyether block amide (PEBA), polyethylene (PE), or silicone. While the flexible overtube 110 is made from a flexible and conformable material, the overtube 110 material should not allow significant stretching. The flexible overtube 110 is made from a thin material so that it can be easily bent, folded, stretched, or deployed. In some embodiments, the thickness of the material can range from 0.01 mm to 0.75 mm. That is, the flexible overtube 110 material should not significantly expand under biaxial, radial, or circumferential forces applied to the overtube material. Once the overtube 110 is deployed, the overtube material should not expand to a significant extent either radially or axially. That is, even if pressure within the overtube 110 increases, the deployed overtube 110 will not significantly stretch like a balloon. In some aspects, introducer 150 comprises a rigid plastic material such as polypropylene (PP), polyvinyl chloride (PVC), polystyrene, nylon, polycarbonate (PC), polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS), or polymethacrylate. In some embodiments, flexible overtube 110 can be approximately 3 feet long. However, it should be understood that flexible overtube 110 can have a shorter or longer length depending on the use case.

[0054] 2D shows anchoring balloon 120 in a flat, deflated state. After deployment, anchoring balloon 120 of guide assembly 100 inflates and assumes a toroidal / donut shape to anchor distal end 114 of guide assembly 100 within the colon, as shown in FIGS. 2A, 2B, and 2C. Upon deployment and anchoring of distal end 114 of guide assembly 100, delivery assembly 200 may be removed from the deployed and anchored guide assembly 100, as described further below.

[0055] As shown in FIG. 3A , in some embodiments, the flexible overtube 110 can be fabricated using blown film extrusion or other methods, and an additional elongated rectangular TPU sheet 119 can be attached to the flexible overtube 110, for example, by welding, with two parallel welds to form an attached anchoring balloon inflation channel 130. As shown in FIG. 3B , in some embodiments, the flexible overtube 110 can be fabricated by wrapping a flat rectangular sheet of TPU around a flat (or shaped) mandrel and welding the ends of the sheet with two parallel straight welds to simultaneously form the flexible overtube 110 with the anchoring balloon inflation channel 130 alongside the flexible overtube 110. In another exemplary method, the flexible overtube 110 and the anchoring balloon inflation channel 130 can be fabricated in a continuous process using a tube former and two parallel welds. The welding can be achieved by heat welding or RF (radio frequency) welding. In other embodiments, the attachment can use adhesives or other joining techniques instead of welding.

[0056] 4, the anchoring balloon 120 may be fabricated by welding two flat circular sheets 1201, 1202 of a polymeric material, such as TPU, at the inner diameter 124, followed by welding at the outer diameter 122. Concurrently with welding the inner diameter 124 of the anchoring balloon 120, the flexible overtube 110 and the anchoring balloon inflation channel 130 may be simultaneously attached to the anchoring balloon 120 at the inner diameter 124. Tape 134, such as Teflon tape, may be placed within the anchoring balloon inflation channel 130 during welding of the inner diameter 124 to maintain a fluid passageway 126 between the anchoring balloon cavity 128 and the anchoring balloon inflation channel 130. After welding at the inner diameter 124 is complete, the tape 134 is removed to form the opening 126. The outer diameter 122 is then welded to form the anchoring balloon cavity 128. The opening 126 allows fluid communication between the anchoring balloon cavity 128 and the anchoring balloon inflation channel 130. Welding may be accomplished by heat welding or RF (radio frequency) welding. In another embodiment, adhesives or other joining techniques may be used for attachment instead of welding. In another embodiment, the anchoring balloon may be directly formed into a toroidal / donut shape.

[0057] FIG. 2A shows the flexible overtube 110 and anchoring balloon 120 of guide assembly 100 in an expanded or deployed state. FIGS. 5B, 5C, 11, 12, and 16 show the flexible overtube 110 stowed to a smaller axial length. FIGS. 11, 12, 15B, 15C, and 16 also show the anchoring balloon 120 in an uninflated, folded state. The folding process, described in more detail below, results in the flexible overtube 110 and anchoring balloon 120 occupying the smaller profile shown in FIGS. 5B, 5C, 15B, 15C, and 16 for insertion into the anus and deployment into the colon.

[0058] As shown in FIG. 16 , in the partially stowed state, the folded (or stowed) portion 116 of the flexible overtube 110 remains in an axially stowed state, i.e., an axially compressed or folded state, and the expanded (or expanded) portion 118 of the flexible overtube 110 is in an expanded or unfolded state, i.e., an uncompressed or unfolded state. As the distal end 114 of the guide assembly 100 advances further within the patient's colon, more of the folded portion 116 of the overtube 110 expands to form the expanded (or expanded) portion 118. In other words, as the flexible overtube 110 is positioned within the colon, the folded portion 116 decreases in length, while the length of the expanded (or expanded) portion 118 of the flexible overtube 110 increases. FIG. 16 also shows the anchoring balloon 120 folded into a smaller diameter configuration.

[0059] By way of example, in some embodiments, efficient stowage of one or both of the flexible overtube 110 and the anchoring balloon 120 can be achieved through several origami-based folding techniques. Origami-based folding techniques have been developed and employed to compactly package deployable space structures within the storage constraints of rocket envelopes, for example, to enable efficient transportation to space. Three such origami folding patterns for the flexible overtube 110 include (a) the Yoshimura pattern, (b) the accordion fold pattern, and (c) the spiral triangular fold. Those skilled in the art will be aware of a wide range of origami patterns that can be used to fold cylinders and flat membranes. Efficient axial stowage of the flexible overtube 110 can be achieved through various patterns derived from stable, inextensible post-buckling patterns of thin-walled cylinders under axial compression or combined axial and torsional loads. Examples are disclosed in Hunt, G.W., and Ario, I., “Twist Buckling and the Foldable Cylinder: An Exercise in Origami,” International Journal of Non-Linear Mechanics, Vol. 40, No. 6, pp. 833-43 (2005); Schenk et al., “Review of Inflatable Booms for Deployable Space Structures: Packing and Rigidization,” Journal of Spacecraft and Rockets, Vol. 51, No. 3 (May-June 2014); and Johnson, W., Soden, P.D., and Al-Hassani, S.T.S., “Inextensional Collapse of Thin-Walled Tubes Under Axial Compression,” Journal of Strain Analysis for Engineering Design, Vol. 12, No. 4, pp. 317-30 (1977). Each of these references is incorporated herein by reference in its entirety.

[0060] FIG. 5A illustrates the Yoshimura pattern, an example of a folding pattern that can be used to store flexible overtube 110. FIG. 5A illustrates the folding pattern on a flat sheet that would be formed if a cylindrical flexible overtube 110 were cut along the length of the cylinder. Solid lines represent mountain folds, and dotted lines represent valley folds. Folding flexible overtube 110 using the folding pattern of FIG. 5A results in the overtube in a collapsed, contracted state, as shown in cross-section in FIGS. 5B and 5C.

[0061] The flat, deflated retention balloon 120 may employ a modified NASA star origami pattern having a hexagonal base, an octagonal base, or other suitable base. FIG. 15A shows an example of a star origami pattern that may be used to fold and store the flat, deflated retention balloon 120. The solid lines in FIG. 15A represent mountain folds, and the dotted lines represent valley folds. FIGS. 15B and 15C show the resulting folded retention balloon 120. FIG. 16 shows the retention balloon 120 of FIGS. 15B and 15C folded over the distal end of the folded portion 116 of the flexible overtube 110. Note also that the retention balloon 120 is attached to the distal end 114 of the flexible overtube 110 at the inner diameter 124 of the retention balloon 120.

[0062] The modified NASA star origami fold pattern with a hexagonal base for the anchoring balloon 120 is compatible with the Yoshimura fold pattern used for the flexible overtube 110, allowing for efficient storage of the anchoring balloon 120 around the flexible overtube 110.

[0063] Those skilled in the art will be aware of the wide range of origami patterns that can be used to fold cylinders and flat membranes. A summary of some origami folding patterns can be found in Nojima T. Modeling of Folding Patterns in Flat Membranes and Cylinders by Origami. JSME International Journal Series C. 2002;45(1):364-370, which is incorporated herein by reference in its entirety.

[0064] In some embodiments, efficient storage of the flexible overtube 110 and the anchoring balloon 120 can be achieved by means other than folding or origami folding of the overtube 110 or the anchoring balloon 120. In some embodiments, the overtube 110 can be shortened by axial bunching or collapsing. Similarly, the anchoring balloon 120 can be folded onto the distal end of the shortened flexible overtube 110 without the use of a pattern and without the use of origami techniques.

[0065] The fixation element need not be an anchoring balloon, and in alternative embodiments, the fixation element may be a structure configured to be housed around the folded portion of the flexible overtube upon deployment and configured to expand to anchor it in the deployed position within the colon.

[0066] 2A, 2B, and 2C, introducer 150 includes a circumferentially discontinuous connection 152 adjacent proximal end 154. Circumferentially discontinuous connection 152 may include lugs or retention surfaces 158 and angled surfaces 156, allowing for attachment and detachment of delivery assembly 200, described in further detail below, to introducer 150. Guide assembly 100 may include an insufflation seal balloon 160, which may be disposed around introducer 150 at its distal end 155, and an insufflation seal balloon port 162 in fluid communication with cavity 164 of insufflation seal balloon 160. Insufflation seal balloon 160 may also be referred to as a sealing cuff. Insufflation seal balloon 160 may be a single donut-shaped balloon. In some embodiments, it may be formed from two concentric tube segments welded or attached axially in two locations. In yet another embodiment, it may be formed by attaching a length of flexible tubing to the rigid introducer 150 at two axial locations. In either case, insertion of the introducer 150 into the anus is performed with the pneumoperitoneum balloon 160 deflated. Inflation of the balloon 160 creates a mechanical engagement with the patient's anus, securing and holding the introducer 150 in place. Deflation of the pneumoperitoneum seal balloon 160 allows adjustment or removal of the introducer 150. Any structures physically connected to the introducer 150 will remain in place with the introducer 150.

[0067] Another function of the pneumoperitoneum sealing balloon 160 is to physically seal off the lumen of the patient's colon from the air outside the patient's body. Once the introducer 150 and its attached structures are secured and held in place, for example, by the sealing cuff 160, it is often beneficial to pressurize the patient's colon with air, carbon dioxide, water, or other fluid. This isolation provided by the pneumoperitoneum sealing balloon 160 serves to maintain this fluid pressure within the lumen of the colon. Accordingly, the guide assembly 100 may include a colonic insufflation port 166 configured to insufflate the colon to a predetermined pressure, for example, with air, carbon dioxide, or water. In the illustrated embodiment, the colonic insufflation port 166 communicates with the colon through the pneumoperitoneum sealing balloon 160. The colonic insufflation portion 166 can be routed through or parallel to another portion of the introducer 150, as long as the portion to the colon is "sealed" from the air by the pneumoperitoneum sealing balloon 160. In another embodiment, the sealing cuff 160 may consist of two donut-shaped balloons axially spaced around the introducer 150 to achieve a more secure fit at the anus and better sealing of the colonic pneumoperitoneum.

[0068] 6A, 6B, and 7, an exemplary delivery assembly 200 according to various aspects of the present disclosure is illustrated. As previously mentioned, delivery assembly 200 can be connected to guide assembly 100 by introducer 150.

[0069] Delivery assembly 200 includes a propulsion balloon 210, a steering mechanism 220, a folding storage member 230, a multi-lumen catheter 240, and a catheter holder 250. Note that the distal end of delivery assembly 200 has components that closely engage elements of guide assembly 100. For example, steering mechanism 220 extends through the folded portion 116 of flexible overtube 110 of guide assembly 100, folding storage member 230 surrounds the folded portion 116 of flexible overtube 110 as well as anchoring balloon 120, and propulsion balloon 210 abuts both the folded portion 116 and the expanding portion 118 of flexible overtube 110, as best seen in FIGS. 11 and 12 .

[0070] The propulsion balloon 210 is one example of a propulsion element for use in the delivery assembly 200. The propulsion element's features include cooperating with the expanded portion 118 of the flexible overtube 110 to form and seal the flexible overtube lumen 111, transmitting distally directed axial forces to the steering mechanism 220 to displace the steering mechanism 220 through the colon, and providing a mechanism for gradually expanding the folded portion 116 of the flexible overtube 110 from the proximal end toward the distal end. For clarity, the propulsion element need not be a balloon. The propulsion element 210 may form a complete seal with the overtube cavity 111 or a leaky seal with the overtube cavity 111.

[0071] The collection of elements, including some or all of the propulsion element 210, flexible overtube 110, steering mechanism 220, and folding and storage member 230, as well as additional structural elements, may be referred to as a propulsion assembly. In other words, the propulsion assembly is the portion of the device that is propelled distally within the colon or other body cavity.

[0072] In some embodiments, intentional steering functionality may not be required. In such embodiments, steering mechanism 220 may be a passive cylinder and may not provide steering action. This cylinder may be flexible or rigid, hollow or filled. In such embodiments, when steering functionality is not required or provided, passive cylinder 220, together with base 222 and radially extending folding storage portion 232, may function as a folding storage element.

[0073] 6B and 8A, the base 222 of the steering mechanism 220 can contact the distal end 212 of the propulsion balloon 210. In the illustrated embodiment, the base 222 of the steering mechanism 220 has a conical profile. However, it should be understood that in other embodiments, the base 222 can have a flat profile or other profile, so long as it allows for gradual expansion of the folded portion 116 of the flexible overtube 110 from the proximal end 112 to the distal end 114, as will be described in more detail below.

[0074] The propulsion balloon 210 can be substantially cylindrical (as opposed to spherical) or elliptical in shape. This can be characterized by the L:D ratio, which is the effective length (L) of the propulsion balloon relative to its diameter (D). Those skilled in the art will appreciate that a spherical balloon in line contact with the flexible overtube 110 will limit the bending moment that can be transferred from the steering actuator to the flexible overtube 110. An inflated cylindrical or elliptical propulsion balloon 210 within the flexible overtube 110 has the ability to transfer greater forces and bending moments. The L:D ratio should not be too large, as a large L:D ratio can increase friction between the propulsion balloon 210 and the flexible overtube 110 and can also increase the turning radius of the flexible overtube 110. In some embodiments, an L:D ratio between about 0.75:1 and 2:1, or between about 0.5:1 and 5:1, has been shown to be useful.

[0075] In a preferred embodiment, as shown in FIG. 8A and simplified FIG. 8B, the steering mechanism 220 may include a thin-walled, flexible silicone cylindrical actuator having three symmetrical internal chambers 224, 225, and 226 and circumferentially oriented reinforcing fibers 221. The circumferentially oriented reinforcing fibers 221, as shown in simplified FIG. 8B, prevent or minimize radial expansion of the cylindrical actuator while allowing individual chamber extension. An equal increase in the internal pressure of the three chambers 224, 225, and 226 may cause the steering actuator to extend axially. An increase in pressure in one or two of the three chambers 224, 225, and 226 causes the steering actuator to bend in the direction opposite the pressurized chamber(s). For example, the simplified depiction of the steering mechanism 220 in FIG. 8B shows that an increase in fluid pressure supplied to the steering chamber 224 causes the steering mechanism 220 to bend away from the pressurized chamber 224. It should be understood that the FMA can achieve three degrees of freedom (pitch, yaw, stretch) of movement and bend in a desired direction by independently controlling the pressure in the three chambers 224, 225, and 226. The static and dynamic deformation characteristics of the maneuvering actuator are described in the publications Suzumori K. Flexible microactuator (1st Report, Static characteristics of 3 DOF actuator). Transactions of the Japan Society of Mechanical Engineers Series C. 1989; 55(518):2547-2552, and Suzumori K. Flexible microactuator (2nd Report, Dynamic characteristics of 3 DOF actuator). Transactions of the Japan Society of Mechanical Engineers Series C. 1990; 56(527):1887-1893. Each of these references is incorporated herein by reference in its entirety.

[0076] Steering mechanism 220 can be made of silicone or other flexible and stretchable polymers / rubbers. Alternatively, it could be made of thermoplastic elastomers, thermoplastic polyurethanes, thermoplastic vulcanizates, or other flexible and stretchable materials. In one embodiment, there can be an axial separation between the three chambers 224, 225, 226 (hollow portions) and the base 222 of steering device 220. That is, the chambers can occupy only a portion of the length of steering device 220, for example, the top two-thirds or one-half of device 220.

[0077] The steering element may be another shape than a cylinder and may include more than one chamber. In one embodiment, the steering element may include three cylindrical chambers, resulting in a different overall shape for the steering element. In some embodiments, the steering element may not include fiber reinforcement.

[0078] In some other embodiments, the steering element may include a different actuation principle instead of pneumatic or hydraulic actuation, such as an electric motor driving an off-axis weighted shaft, a vibration motor, a Bowden cable pull wire commonly used for steering in catheters, multiple fluid jets at the distal end oriented radially, axially, or circumferentially to apply a force or torque on the distal end of the flexible overtube to steer it, or other steering mechanisms known to those skilled in the art.

[0079] Catheter 240 may include one or more lumens, as shown in cross section in Figure 9. One such lumen may be a propulsion balloon inflation lumen 242 that is in fluid communication with propulsion balloon 210 by way of a propulsion balloon inflation port 260 in catheter 240, as shown in Figures 6B and 8A. The propulsion balloon inflation lumen may be used to inflate and / or deflate propulsion balloon 210.

[0080] In addition to the propulsion balloon inflation lumen 242, the catheter 240 may include multiple lumens, e.g., three steering pressure lumens 244, 245, and 246, as shown in FIG. 9. The steering pressure lumens 244, 245, and 246 are in fluid communication with the steering chambers 224, 225, and 226 of the steering mechanism 220 through steering ports 280, 281, and 282, respectively, as shown in FIG. 8A. The multi-lumen catheter 240 may extend through a propulsion element, e.g., the propulsion balloon 210, to establish a fluid connection between the steering chambers 224, 225, and 226 of the steering mechanism 220 and a fluid control system 300, which is described in more detail below. Note that the propulsion balloon inflation lumen 242 may be sealed at the distal end of the catheter.

[0081] In the illustrated embodiment, the multi-lumen catheter 240 may be housed within a catheter holder 250. The catheter 240 may provide fluid or fluid pressure to the propulsion balloon 210 and steering mechanism 220 of the delivery assembly 200 as they move into the colon while the proximal end of the delivery assembly 200 remains attached to the anus or fluid control system 300.

[0082] The catheter holder 250 includes a rotatable connector 252 adjacent the distal end 254 of the catheter holder. The connector 252 comprises a circumferentially discontinuous structure including an angled surface 256 and a retention surface 258 (or lug 258) that allows attachment and detachment of the introducer 150 of the guide assembly 100. The catheter 240 can be wound onto a larger diameter take-up cylinder 262 near the proximal end 266 of the catheter holder 250, as shown in FIGS. 6A, 6B, 7, 11, and 12. The catheter 240 advances from the distal end 268 of the catheter holder into the guide assembly 100. This advancement is accompanied by a twisting of the catheter, the number of twists being equal to the number of turns of the catheter 240 within the catheter holder 250. The larger diameter of the take-up cylinder 262 reduces the number of turns required to accommodate the length of the catheter 240, thereby limiting twisting of the catheter 240 during deployment of the delivery assembly 200. The diameter 264 of the catheter holder distal end approximates the diameter of the flexible overtube 110 of the guide assembly 100. The catheter holder 250 may include a support 251, e.g., a conical support, configured to provide a guide surface for the catheter 240 to transition from the larger diameter take-up cylinder 262 at the proximal end 266 to the smaller diameter 264 at the distal end 268.

[0083] In another embodiment, the catheter may be housed outside the "catheter holder" and may be fed into the flexible overtube lumen 111 as the driving balloon 210 and steering actuator 220 of the delivery assembly 200 are advanced into the colon. However, in this case, the driving pressure (P propulsion ) can create a leak path and introduce noise due to the leak. Efforts to minimize leakage can introduce friction that makes advancement of the propulsion balloon 210 and steering actuator 220 of the delivery assembly 200 more difficult.

[0084] The folding storage member 230 may be attached to the steering mechanism 220 at a location spaced distally from the base 222 of the steering mechanism 220. The folding storage member 230 is configured to store the folded portion 116 of the flexible overtube 110 between itself and the base 222 of the steering mechanism 220. The folding storage member 230 may include a radially extending storage section 232. In some embodiments, the radially extending section 232 may be discontinuous in the circumferential direction. In some embodiments, the folding storage member 230 is configured to store the folded portion 116 of the flexible overtube 110 and the folded anchoring balloon 120. For example, the folding storage member 230 may include an axially extending storage section 234 that is spaced from, and therefore does not interfere with, the operation of the steering mechanism 220. In some embodiments, axially extending portion 234 can extend entirely or partially to the base of steering actuator 222. In some embodiments, axially extending portion 234 can be circumferentially discontinuous. The exposed portions of folding storage device 230 and steering mechanism 220, in some embodiments, are portions of the device that contact and move relative to the colon during deployment of overtube 110. Therefore, it can be advantageous to apply a friction-reducing coating to these surfaces of the exposed portions of folding storage device and steering mechanism.

[0085] Those skilled in the art will recognize that the storage element may not use a mechanical storage mechanism. In some embodiments, folding storage may be achieved through the use of temporary adhesives (also known as temporary glues) or hook-and-loop fasteners, both of which are released upon deployment. In some embodiments, the folds in the folded portion 116 of the flexible overtube 110 and the folded anchoring balloon 120 may be set by thermally annealing the folded structure. In such embodiments, the thermally set folded shape may provide folding storage without the need for a storage member 230.

[0086] In the accompanying figures, storage device 230 is shown as having a “bluff-body” or “non-aerodynamic” shape. In alternative embodiments, storage device 230 may have an “aerodynamic or smooth” shape to facilitate insertion into the colon. In the accompanying figures, steering mechanism 220 extends / protrudes axially beyond the distal end of storage device 230. In an alternative embodiment, storage device 230 may be connected to steering device 220 at its distal tip. In some embodiments, folded storage member 230 may have a small thickness and may be made from a flexible material (such as silicone, another rubber or thermoplastic elastomer, or thermoplastic polyurethane, or thermoplastic vulcanizate, or another material with high flexibility and stretchability) so that folded storage member 230 can be inverted to enable easy removal of delivery assembly 200 from guide assembly 100 after deployment and fixation of the distal end of guide assembly 110.

[0087] The deployment device 1000 includes a guide assembly 100 and a delivery assembly 200 coupled together by a circumferentially discontinuous connection 152 on the introducer 150 and a circumferentially discontinuous connection 252 on the catheter holder 250. To couple the guide assembly 100 and the delivery assembly 200, the circumferentially discontinuous connection 152 on the introducer 150 is axially inserted into the rotatable circumferentially discontinuous connection 252 on the delivery assembly 200. The connection is then rotated, causing the angled surfaces 156 and 256 on the connections 152 and 252 to clamp the two assemblies 100, 200 together and compressing the O-ring 290 to seal the interface of the two assemblies 100, 200. The two assemblies 100, 200 are held together by corresponding retention surfaces 158 and 258 on the two connections 152 and 252. The connection between the guide assembly and delivery assembly connects the delivery assembly lumen 211 and the flexible overtube lumen 111. Compressing the O-ring ensures a leak-free interface where the two cavities 111 and 211 connect. It should be understood that other conventional mechanisms can be employed to removably connect and seal the two assemblies 100, 200.

[0088] In some embodiments, guide assembly 100 and delivery assembly 200 may be fixedly coupled to one another, eliminating the need for connectors 152 and 252 and O-ring 290.

[0089] 11 and 12 , for example, flexible overtube 110 of guide assembly 100 can have a folded or retracted portion 116 and an expanded (or expanded) portion 118. Folded portion 116 can be disposed distal to expanded portion 118. An anchoring balloon 120 is folded around folded portion 116 of flexible overtube 110. Propulsion balloon 210 of delivery assembly 200 can be disposed within expanded portion 118 of flexible overtube 110 of guide assembly 100. Folded portion 116 of flexible overtube 110 and folded anchoring balloon 120 can be stored distal to propulsion balloon 210. Folded portion 116 of flexible overtube 110 and folded anchoring balloon 120 can be disposed around steering mechanism 220 and stored within folding storage member 230.

[0090] During operation of the deployment device 1000 with the guide assembly 100 and delivery assembly 200 assembled, the distal end of the deployment device 1000 is inserted through the anus and into the colon until the introducer 150 is adjacent the anus so that the flexible overtube 110, among other structures distal to the introducer 150, is deployed within the colon. In particular, placement of the sealing balloon 160 adjacent the anus is the optimal placement for embodiments of the device.

[0091] Typically, an empty, collapsed human colon presents a difficult environment for the insertion of anything, including flexible overtube 110. Because an insufflated colon, i.e., a colon filled with gas or other fluid, presents a more favorable topography for insertion of flexible overtube 110 compared to a collapsed colon, in some embodiments, the colon may be insufflated prior to deployment of flexible overtube 110. After introducing device 150 is positioned adjacent to the anus, colonic insufflation balloon 160 may be inflated to seal the anus. The colon is inflated by the insufflation pressure (P) of fluid control system 300, as described in more detail below. Insufflation ) Insufflation can be achieved with carbon dioxide, air, or water through a colonic insufflation port 166 connected to a regulator.

[0092] 13 and 14 depict propulsion of the device into the colon by inflation of flexible overtube lumen 111, gradually expanding folded portion 116 of flexible overtube 110 from its proximal end to its distal end, with the transition between folded portion 116 and deployed portion 118 adjacent base 222 of steering mechanism 220 and distal end 212 of propulsion balloon 210. To enable such propulsion, propulsion balloon 210 may be inflated, establishing a seal between the outer wall of propulsion balloon 210 and the inner wall of flexible overtube 110, forming flexible overtube lumen 111. Increased fluid pressure within flexible overtube lumen 111 exerts a force on proximal end 214 of propulsion balloon 210, moving propulsion element 210 and steering mechanism 220 distally within the patient's insufflated colon. The fluid pressure within the sealed flexible overtube lumen 111 and delivery assembly lumen 211 of the connected delivery assembly 200 is controlled by the driving pressure (P Propulsion) comes from a pressurized fluid (e.g., air, carbon dioxide, water, etc.) delivered through a propulsion pressure port 270 that is connected to a regulator. The propulsion pressure port 270 may be in the wall of the delivery assembly 200 or the wall of the introducer 150, or may be delivered through a lumen of a multi-lumen catheter. The propulsion pressure port 270 is only required to connect the fluid control system 300 to either the flexible overtube lumen 111 or the delivery assembly lumen 211.

[0093] When the flexible overtube lumen 111 expands, a driving pressure (P Propulsion ) advances the propulsion balloon 210, along with the attached steering mechanism 220, within the flexible overtube 110. Because the proximal end 112 of the flexible overtube 110 is attached to the introducer 150, this advancement of the propulsion balloon 210 and steering mechanism 220 gradually expands the collapsed portion 116 of the flexible overtube 110 from the proximal end toward the distal end, beyond the base 222 of the steering mechanism 220, so that the propulsion balloon 210 seals with and passes through the expanded or inflated portion 118 of the flexible overtube 110.

[0094] Stated another way, gradually expanding the folded portion 116 of the flexible overtube 110 stretches the flexible overtube lumen 111 and the inflation portion 118 of the flexible overtube 110 in length, resulting in the distal end 114 of the flexible overtube 110, as well as the propulsion balloon 210 and steering mechanism 220, advancing distally into the colon. This deployment of the flexible overtube 110 can be referred to as a gradual actuation or controlled deployment of the flexible overtube 110. Specifically, the entire length of the flexible overtube 110 does not inflate / expand simultaneously. Instead, the flexible overtube 110 gradually inflates / expands from the proximal end 112 of the flexible overtube 110 toward the distal end 114 of the flexible overtube 110. That is, the folded portion 116 of the flexible overtube 110, housed within the housing member 230, advances, and the expanded portion 118 of the flexible overtube 110 secures against the colon upon expansion. This can also be visualized as the flexible overtube 110 expanding through tip dilation, resulting in the device being less prone to looping. This gradual expansion from the proximal to distal end is an important functional feature of the deployment device 1000.

[0095] As expansion progresses, the folded portion 116 of the flexible overtube 110 clears from the fold storage member 230. When the folded portion 116 is fully expanded, movement of the flexible overtube 110 ceases, leaving only the anchoring balloon 120 distal to the base 222 of the steering mechanism 220. In one embodiment, the flat sheet 1201, which is welded or otherwise attached to the flat sheet 1202 to create the deflated anchoring balloon 120, can have an inner diameter smaller than the outer diameter of the base 222. This arrangement prevents the steering mechanism 220 or the base 222 of the propulsion balloon 210 from moving beyond the anchoring balloon 120. As previously described, inflation of the anchoring balloon 120 results in frictional anchoring of the flexible overtube 110 within the patient's colon. The delivery assembly 200 is removed from the overtube lumen 111 before the colonoscope is inserted.

[0096] The bending direction of steering mechanism 220 can be controlled by independently controlling the pressure applied to the three chambers 224, 225, and 226 by an electro-pneumatic or electro-hydraulic pressure control system 300. The internal pressures of the three steering chambers 224, 225, and 226 can be independently controlled through steering pressure lumens 244, 245, and 246 of multi-lumen catheter 240, which are connected to steering control valves 326, 327, and 328 of fluid control system 300.

[0097] Referring to FIG. 18 , fluid control system 300 includes a source or supply of pressurized fluid 310. The fluid may be air, carbon dioxide, water, or any suitable fluid. The source of pressurized fluid 310 is in fluid communication with a steering pressure regulator 320, a propulsion pressure regulator 330, and a colon pneumoperitoneum pressure regulator 340, which regulate the steering pressure, propulsion pressure, and colon pneumoperitoneum pressure, respectively. The flow of pressurized fluid from steering pressure regulator 320 is routed through a first on / off valve 322 to a steering control valve manifold 324. Steering control valve manifold 324 includes three electronically controlled on / off solenoid valves 326, 327, and 328. In some embodiments, these valves may be configured for on / off switching control, as described below.

[0098] FIG. 10 illustrates an exemplary steering control valve schedule that controls the order in which pressure is applied to the three steering chambers 224, 225, and 226. The valve schedule depicted in FIG. 10 shows that the steering control valves 326, 327, and 328 are cycled on and off. This causes the steering mechanism 220 to rotate in one direction (e.g., clockwise). Reversing the order in which the valves are actuated (i.e., actuating 328, then 327, then 326) reverses the direction of rotation of the steering actuator (e.g., counterclockwise). The force exerted by the colon wall on the steering actuator depends on the direction of rotation. Switching the direction of rotation changes the direction of the force on the steering actuator. This allows the steering mechanism 220 to steer the delivery assembly 200 past obstacles and find the path of least resistance as it navigates the tortuous colon. This prevents the propulsion balloon 210 and steering actuator 220 from becoming stuck or remaining stuck during insertion, allowing for automatic deployment of the device into the large intestine.

[0099] The amplitude of the displacement of the steering actuator is controlled by the steering pressure (P Steering) The frequency of rotation can be controlled by changing the period (T) of the valve schedule, as shown in the example valve schedule of FIG. 10. The direction of rotation can be changed by shuffling the order of the valves in the valve schedule, as previously described. As shown in the example valve schedule of FIG. 10, the two valves rotate for a certain duration (T overlap ) can be on at the same time. The overlap ratio (T Overlap / T) can be varied to control the continuity (jerky or smooth) of the steering actuator rotation.

[0100] In another embodiment, pulse width modulation (PWM) may be used to control valves to control the pressure supplied to the three separate internal chambers 224, 225, 226 of the steering mechanism 220. The physician may steer based on position, orientation, and trajectory feedback from electromagnetic (EM) sensors or other feedback mechanisms.

[0101] The propulsion pressure regulator 330 regulates the propulsion pressure (P ) supplied to the delivery assembly lumen 211 and flexible overtube lumen 111 proximal to the propulsion balloon 210 to control the propulsion of the propulsion balloon 210 and, therefore, the expansion of the flexible overtube 110. Propulsion The flow is routed through a second on / off valve 332.

[0102] The colonic pneumoperitoneum pressure regulator 340 regulates the colonic pneumoperitoneum pressure (P colon-insufflation) to regulate the pressure in the colon. Flow is sent to the colon through a third on / off valve 342. The system may also include a pressure relief valve 344 to ensure that pressure in the colon does not exceed safe pressure limits. Fluid control system 300 may also include a first syringe 350 configured to inflate and deflate propulsion balloon 210 through a first three-way stopcock valve 352 and propulsion balloon inflation lumen 242, a second syringe 360 ​​configured to inflate and deflate fixation balloon 120 through a second three-way stopcock valve 362 and fixation balloon inflation port 132, and a third syringe 370 configured to inflate and deflate pneumoperitoneum seal balloon 160 through a third three-way stopcock valve 372 and pneumoperitoneum seal balloon port 162.

[0103] Referring now to FIG. 17, the use of a flexible overtube 110 to aid in the insertion of a colonoscope 400 is described. As shown in FIG. 17A, an introducer 150 is inserted into the anus, and the flexible overtube 110 is deployed to a desired location within the colon. While other portions of the device 1000 remain coupled to the overtube 110 at this point, only the overtube 110 is shown in FIG. 17 for purposes of clarity. FIG. 17B shows the inflation of the anchoring balloon 120 after deployment of the flexible overtube 110 within the colon. In the illustrated embodiment, this anchoring balloon 120 is annular / donut shaped.

[0104] As shown in FIG. 17C , once the anchoring balloon 120 is inflated to anchor the distal end 114 of the flexible overtube 110 at a desired location within the colon, a proximal “pulling” force, indicated by the arrow, may be applied to the introducer 150 or any other structure connected to the proximal end 112. This pulling force places tension on the flexible overtube 110 because the distal end of the flexible overtube 110 is held in place relative to the colon by the balloon 120. FIGS. 17A and 17B show the sigmoid colon 297 and transverse colon 298 in a “looped” configuration. Applying tension to the overtube 110 eliminates this “looping,” as seen in FIG. 17C . This is referred to as “colonic shortening,” because eliminating the “looping” in the sigmoid colon 297 and transverse colon 298 results in a shortening of the colon. Typically, removal of the delivery assembly 200 can occur any time after inflation of the balloon 120 but before insertion of the scope 400. That is, any structural elements within the overtube 110 are removed therefrom prior to insertion of the scope 400. The "shortening" of the colon facilitates easier insertion of the colonoscope 400, thereby reducing mucosal stretching and pain for the patient. This also reduces the musculoskeletal strain on the endoscopist and nurse during colonoscope insertion, reducing the risk of endoscopy-related injury.

[0105] In one embodiment in which the propulsion element comprises a propulsion balloon 210, the delivery assembly 200 is removed from the guide assembly 100 by deflating the propulsion balloon 210 and pulling the catheter 240, leaving only the flexible overtube 110 and the anchoring balloon 120 within the colon. As previously described, the folding storage member 230 may be inverted to allow for easy removal of the delivery assembly 200 from the guide assembly 100. With the delivery assembly 200 removed, the physician or nurse can insert the colonoscope 400 through the flexible overtube 110 to a position within the colon beyond the anchoring balloon 120, as seen in FIG. 17D .

[0106] FIG. 17D shows the distal end of the colonoscope 400 extending beyond the distal end of the flexible overtube 110, i.e., the distal end of the anchoring balloon 120, to or near the cecum 299. Once the colonoscope 400 reaches the cecum 299, the anchoring balloon 120 is deflated, allowing the overtube 110 to be removed. The overtube 110 may be removed at any time after scope placement until scope removal. In either case, inspection of the colonic mucosa is performed upon scope removal, which is standard medical practice, and the flexible overtube 110 does not interfere with inspection of the colonic mucosa. In an alternative embodiment, the anchoring balloon 120 may be re-inflated to allow repeated insertion of the colonoscope 400 and / or insertion of alternative tools, instruments, or endoscopes that may be required during the interventional procedure. Re-inflation may occur proximal to the intervention site and may be accomplished by withdrawing a portion of the overtube 110 from the colon while the anchoring balloon 120 is deflated. Figure 17E shows the balloon 120 deflated, leaving the overtube 110 in place. Figure 17F shows the colonoscope 400 remaining in place while the overtube 110 is completely withdrawn from the colon.

[0107] The electromagnetic (EM) tracking system consists of an EM field generator 501, a 5-DOF (degree of freedom) EM sensor 248 attached to the device, and a 6-DOF (degree of freedom) EM sensor 502 attached to the patient, as shown in FIG. 19B. In FIG. 19B, most of the equipment containing the EM coil 248 has been removed for clarity. The magnetic field generator 501 can take the form of a wide plate placed below the patient, as shown in FIG. 19B, or a planar magnetic field generator that can be positioned above the patient using a positioning arm. FIG. 19A is a close-up view of one embodiment including an electromagnetic (EM) coil 248 attached to a device that can be embedded at any distal location of the guide assembly 100 or at a distal location of the delivery assembly 200 and moves with its distal end. In FIGS. 8A and 11, the EM coil 248 is shown embedded inside the propulsion balloon 210 and embedded within the propulsion balloon inflation lumen 242. The axis of the EM coil 248 is oriented along the axis of the propulsion balloon 210. In another embodiment, the EM coil 248 may be embedded within the lumen of the multi-lumen catheter 240, wrapped around the multi-lumen catheter 240, or embedded adjacent to the multi-lumen catheter 240. In one embodiment, the EM coil 248 may comprise a wire wound around a solid or hollow ferromagnetic core for optimal sensitivity. The EM coil 248 may be connected to a twisted wire cable 249, which may be connected to the system control unit of the EM tracking system. The twisted wire cable 249 may be routed through the propulsion balloon inflation lumen 242 in a four-lumen catheter or through another lumen in a five-lumen catheter. In another embodiment, the twisted wire cable may be routed in parallel with the multi-lumen catheter. In an alternative embodiment, the EM coil 248 or additional EM coils may be incorporated into the actuator of the steering device, preferably at the distal end of the actuator. A single EM coil provides five degrees of freedom feedback regarding the position and orientation of the distal end of the device.

[0108] The device-mounted EM coils 248, along with an EM tracking system, provide 5-DOF (degrees of freedom) feedback regarding the position (x, y, z) and orientation (pitch and yaw) of the propulsion balloon 210 relative to the EM field generator 501. A patient-mounted 6-DOF EM sensor 502 containing two EM coils is provided and worn by the patient during the procedure to provide 6-DOF relative position and orientation information to the EM field generator 501. The EM tracking system calculates the position and orientation of the propulsion balloon relative to the patient reference sensor 502. This calculation takes into account patient movement of the field generator 501 during the procedure.

[0109] The EM tracking system also generates images to display the current location, current orientation, and trajectory taken by the device-mounted EM sensor 248 relative to the patient-mounted EM sensor 502. Figures 20A and 20B are exemplary 2D and 3D graphical outputs, respectively, of the EM tracking system tracking the movement of the device-mounted EM coil 248 within the patient's colon relative to the patient-mounted sensor 502. These outputs allow for real-time tracking of the EM coil and, therefore, any instrumentation associated with it.

[0110] In summary, this disclosure describes the efficient storage of flexible overtube 110 in an origami folding pattern (or a pattern derived from the stable inextensible post-buckling pattern of a thin-walled cylinder under axial compression or combined axial-torsion loading), the carriage of the efficiently stored overtube 110 at its distal end within a folding storage mechanism (as opposed to the tube being stored within a base for the everting tube mechanism), and the gradual actuation / deployment of flexible overtube 110 from proximal end 112 toward distal end 114. This storage provides an ideal method for providing a propulsion and steering mechanism for deploying flexible overtube 110.

[0111] While the foregoing detailed description has set forth several non-limiting embodiments, it should be understood that numerous variations exist. It should also be understood that the exemplary embodiment(s) are merely illustrative and are not intended to limit the scope, applicability, or configuration of the present disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment(s). It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the present disclosure, as set forth in the appended claims and the legal equivalents thereof.

Claims

1. A deployment device, a flexible overtube having a folded portion and an expanded portion, wherein a proximal end of the flexible overtube comprises the expanded portion and a distal end of the overtube comprises the folded portion; an introducer fixedly coupled to the proximal end of the flexible overtube; a propulsion element coupled to a distal end of the expanded portion of the flexible overtube, the expanded portion of the overtube and the propulsion element forming an enclosed tubular cavity; Equipped with the pusher element is configured to gradually expand the folded portion of the flexible overtube from a proximal end of the folded portion toward a distal end of the folded portion to extend a length of the expanded portion of the flexible overtube and the tubular cavity, and the pusher element advances distally relative to the introducer in response to a force applied to the pusher element. Deployment device.

2. 10. The deployment device of claim 1, wherein the folding pattern of the folded portion of the flexible overtube comprises a stable, inextensible post-buckling pattern of a thin-walled cylindrical tube under axial compression or combined axial-torsion loading.

3. 10. The deployment device of claim 1, wherein the propulsion element comprises a propulsion balloon that can be inflated to form a seal with an inner surface of the expanded portion of the flexible overtube adjacent a distal end of the expanded portion.

4. The deployment apparatus of claim 1 , further comprising a storage element configured to axially contain the folded portion of the flexible overtube.

5. The deployment device of claim 1 , further comprising a steering element coupled to the propulsion element and configured to interact with an environment to change the direction of advancement of the flexible overtube.

6. 6. The deployment device of claim 5, wherein the steering element comprises a flexible element including two or more internal chambers, a base of the flexible element coupled to the propulsion element, the flexible element extending through the folded portion of the flexible overtube, each internal chamber being selectively pressurizable and depressurizable, and wherein selective pressurization of the chambers causes the flexible element to bend in a steering direction, and the deployment device comprises a multi-lumen catheter supplying pressurized fluid to each internal chamber, the catheter extending to the introducer and further comprising a fluid supply system adapted to supply fluid pressure to the chambers.

7. 7. The deployment device of claim 6, wherein the flexible element is a cylinder including three or more internal chambers circumferentially symmetrically arranged and reinforced with circumferentially oriented fibers, and further wherein sequential pressurization and depressurization of the chambers results in circular motion of the steering actuator.

8. The deployment device of claim 6 , wherein the multi-lumen catheter is housed within a catheter holder having a cavity adapted to contain a pressurized fluid.

9. The deployment device is configured to be deployed within the colon of a patient, the deployment device comprising: a fixation element attached to the distal end of the flexible overtube and configured to maintain the distal end of the flexible overtube in a deployed position; The deployment device of claim 1 further comprising:

10. 10. The deployment device of claim 9, wherein the propulsion element is configured to be detachable from the flexible overtube and configured to form a tubular cavity within the patient's colon from the introducer to the deployment location and to guide an endoscope to the deployment location.

11. The deployment device is configured to be deployed within a colon of a patient, the deployment device comprising: an annularly shaped anchoring balloon attached to the distal end of the flexible overtube, the anchoring balloon configured to fold around the folded portion of the flexible overtube, the anchoring balloon also configured to be inflatable to frictionally engage an inner surface of the patient's colon to maintain the distal end of the flexible overtube in a deployed position; an inflation channel attached to the anchoring balloon and configured to inflate and deflate the anchoring balloon; The deployment device of claim 1 further comprising:

12. The deployment device is configured to be deployed within the colon of a patient, the deployment device comprising: an insufflation seal attached to the introducer, the insufflation seal configured to form a seal between the introducer and the patient's colon; and a colonic insufflation port disposed adjacent to and distal to the insufflation seal member, the colonic insufflation port configured to deliver pressurized fluid to the patient's colon to insufflate the patient's colon; and The deployment device of claim 1 further comprising:

13. The deployment device is configured to be deployed within the colon of a patient, the deployment device comprising: a steering element coupled to the propulsion element and configured to interact with an inner surface of the patient's colon to periodically change the direction of advancement of the flexible overtube; The deployment device further comprises:

14. The deployment device of claim 13 , wherein the steering element is configured to periodically rotate clockwise or counterclockwise to periodically change the direction of advancement of the flexible overtube.

15. 1. A method for guiding an endoscope to an in vivo deployment location within a patient's colon, the method comprising: inserting an introducer into a proximal end of the patient's colon; securing the introducer in place near the proximal end of the colon; advancing a pusher assembly distally into the patient's colon, a distal end of a flexible overtube coupled to the pusher assembly and a proximal end of the flexible overtube coupled to the introducer; deploying the flexible overtube, the flexible overtube having a folded portion and an expanded portion, wherein deploying the overtube includes expanding the folded portion to extend the expanded portion until the distal end of the flexible overtube reaches the deployed position, the deployment of the overtube resulting in advancing the propulsion assembly, and the deployment of the flexible overtube resulting in forming a sealed tubular space surrounded by the flexible overtube; supplying pressurized fluid to the enclosed lumen of the overtube, the pressurized fluid exerting an axial force on a thruster element of the thruster assembly to advance the thruster assembly distally relative to the introducer; inserting the endoscope into the proximal end of the flexible overtube through the enclosed tubular space to the distal end of the overtube and thus to the deployed position; A method comprising:

16. inflating an anchoring balloon attached to the distal end of the flexible overtube, whereby the distal end of the flexible overtube frictionally engages the inner surface of the colon and anchors the flexible overtube in place relative to the patient's colon; Deflating the anchoring balloon so that the overtube is no longer anchored in place relative to the patient's colon; and adjusting the position of the flexible overtube relative to the patient's colon; re-inflating the fixation balloon; 16. The method of claim 15, further comprising:

17. the propulsion assembly includes a propulsion balloon, and the method comprises: and inflating the propulsion balloon to form a seal between the inflated propulsion balloon and the inner surface of the flexible overtube, wherein the axial force is applied to a proximal portion of the inflated propulsion balloon.

16. The method of claim 15.

18. the propulsion assembly further includes a steering element having a proximal end, a distal end, and a flexible cylinder containing two or more internal chambers, the distal end of the steering element comprising the distal end of the delivery assembly when the delivery assembly is in a use state, and the method further comprises: steering the propulsion assembly by selectively pressurizing and depressurizing the internal chamber of the steering element, resulting in the flexible cylinder curving in a steering direction, steering including periodically varying the rotation of the distal end of the steering element, resulting in a periodically changing direction of travel of the propulsion assembly; 16. The method of claim 15.

19. forming a seal between the introducer and the patient's colon by inflating a sealing member attached to the introducer; insufflating the patient's colon by injecting pressurized fluid into the patient's colon distal to the insufflation seal member through an insufflation port; 16. The method of claim 15, further comprising:

20. 1. A method for guiding an endoscope to an in vivo deployment location within a patient's colon, the method comprising: inserting an introducer and propulsion assembly into a proximal end of the patient's colon, the propulsion assembly comprising a propulsion element and a flexible overtube; advancing the pusher assembly distally into the patient's colon, wherein a distal end of the overtube is connected to the pusher assembly and a proximal end of the overtube is connected to the introducer, such that advancement of the pusher assembly results in deployment of the flexible overtube and in the formation of a sealed tubular space surrounded by the flexible overtube, and the pusher assembly is advanced to a deployed position within the patient's colon; inflating an anchoring balloon attached to the distal end of the flexible overtube, the anchoring balloon configured to maintain the distal end of the overtube in the deployed position; shortening the patient's colon by applying a tension force on one or both of the flexible overtube and the propulsion element; removing the propulsion element from the flexible overtube; inserting the endoscope into the proximal end of the flexible overtube through the enclosed tubular space to the distal end of the overtube and thus to the deployed position; A method comprising:

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