Variable Exposure Needle

Abstract

A system for accessing the bile duct includes an access cannula and a needle. The cannula extends along a longitudinal axis from a proximal end to a distal end. The cannula includes a channel extending longitudinally through the cannula. The distal portion of the cannula includes a laser cut pattern. The laser cut pattern includes a plurality of slots through the wall of the cannula such that the cannula is movable between a biased, uncompressed configuration and a compressed configuration in which it is compressed along the longitudinal axis. The needle extends longitudinally from the proximal end to a sharpened distal end. The needle is housed within the channel such that the sharpened distal end is covered by the cannula when the cannula is in the uncompressed configuration and is exposed for puncturing the wall of one of the organ and the target duct when the cannula is in the compressed configuration.

Description

[Technical Field]

[0001] The present disclosure relates to a variable exposure needle for endoscopic ultrasound (EUS) procedures. This disclosure claims priority to U.S. Provisional Patent Application No. 63 / 386,415, filed December 7, 2022, the disclosure of which is incorporated herein by reference. [Background technology]

[0002] Endoscopic ultrasound (EUS) is a minimally invasive procedure performed using certain endoscopes that use high-frequency sound waves to visualize, for example, the digestive (gastrointestinal) tract and other nearby structures. According to one application, EUS is used to facilitate direct biliary drainage when traditional endoscopic retrograde cholangiopancreatography (ERCP), which utilizes contrast and X-rays to identify and treat blockages within the ducts via the papilla, fails. EUS can be used to visualize ducts directly through the stomach wall, facilitating needle puncture to gain guidewire access to the common bile duct or pancreatic duct.

[0003] Successful EUS access procedures generally depend on initial ductal puncture and intraductal access cannula stability during passage of a guidewire to the target site. However, the ability to easily puncture the duct while maintaining stability for guidewire access can be difficult to achieve in some cases. Additionally, the use of needles to puncture ducts, especially smaller ducts, poses an inherent risk of through-puncture, in which the needle tip not only punctures the proximal wall of the duct but also passes through the distal wall of the duct. Summary of the Invention

[0004] The present disclosure relates to a system for accessing a bile duct, the system including an access cannula extending along a longitudinal axis from a proximal end to a distal end, the access cannula including a channel extending longitudinally therethrough, a distal portion of the access cannula including a laser cut pattern including a plurality of slots extending through a wall of the access cannula to enable the access cannula to move between a biased, uncompressed configuration and a compressed configuration compressed along the longitudinal axis.

[0005] The system also includes a needle extending longitudinally from a proximal end to a sharpened distal end, the needle received within the channel of the access cannula such that the sharpened distal end is covered by the access cannula when the access cannula is in the uncompressed configuration and is exposed for puncturing a wall of one of an organ and a target vessel when the access cannula is in the compressed configuration.

[0006] In one embodiment, the laser cutting pattern includes a plurality of rows each extending around the circumference of the access cannula, each of the plurality of rows including at least one slot extending through the wall of the access cannula along a portion of the row, the channel of the access cannula opening to and communicating with the exterior of the access cannula through the slot.

[0007] In one embodiment, each row of the laser cut pattern extends perpendicular to the longitudinal axis of the access cannula. In one embodiment, the laser cutting pattern is selected to achieve a desired level of compressibility of the access cannula, the desired level of compressibility including the compressive force required to move the access cannula from the uncompressed configuration towards the compressed configuration and the length shortened when the access cannula is moved from the uncompressed configuration towards the compressed configuration.

[0008] In one embodiment, the desired level of compressibility achieved by the laser cut pattern is based on one of the number of slots per row, the dimensions of each of the slots, the rotation angle between corresponding slots in adjacent rows, and the distance between rows.

[0009] In one embodiment, the distal-most tip of the needle projects distally beyond the distal end of the access cannula in the uncompressed configuration. In one embodiment, when the access cannula is moved from the uncompressed configuration to the compressed configuration, the access cannula is shortened a distance corresponding to the sharpened distal end of the needle.

[0010] In one embodiment, the length of the sharpened distal end of the needle exposed when the access cannula is in the compressed configuration is less than the length of the target vessel to prevent through-puncture.

[0011] In one embodiment, the access cannula is formed from nitinol hypotube. The present disclosure also relates to a needle system for treating a bile duct, the system including an access cannula configured with a size and shape for insertion through a working channel of an endoscope, the access cannula having a generally tubular body extending along a longitudinal axis from a proximal end to a distal end, a portion of the access cannula including a laser cut pattern including a plurality of slots extending through a wall of the access cannula to allow the access cannula to be compressed along the longitudinal axis.

[0012] The system includes a needle removably received within the access cannula and extending longitudinally from a proximal end to a sharpened distal end that is covered by the access cannula when the access cannula is in an uncompressed configuration and that is exposed when the access cannula is in a compressed configuration.

[0013] In one embodiment, the access cannula is biased toward the uncompressed configuration such that the access cannula is movable between the uncompressed and compressed configurations.

[0014] In one embodiment, the laser cutting pattern includes a plurality of rows each extending around the circumference of the access cannula, each of the plurality of rows including at least one slot extending through the wall of the access cannula along a portion of the row, the channel of the access cannula opening to and communicating with the exterior of the access cannula through the slot.

[0015] In one embodiment, the laser cutting pattern is selected to achieve a desired level of compressibility of the access cannula, the desired level of compressibility including the compressive force required to move the access cannula from the uncompressed configuration towards the compressed configuration and the length shortened when the access cannula is moved from the uncompressed configuration towards the compressed configuration.

[0016] In one embodiment, the desired level of compressibility achieved by the laser cut pattern is based on (a) the number of slots per row, (b) the dimensions of each of the slots, (c) the rotation angle between corresponding slots in adjacent rows, and / or (d) the distance between rows.

[0017] In one embodiment, the access cannula is formed from nitinol hypotube. The present disclosure also relates to a method for accessing a bile duct, comprising inserting an endoscope into a target area within a stomach, inserting an access cannula in an uncompressed configuration through a working channel of the endoscope, and positioning a distal end of the access cannula against a portion of a stomach wall adjacent a target wall of a target duct to be accessed, the access cannula including a laser cut pattern including a plurality of slots extending through a wall of the access cannula such that the access cannula is movable between the uncompressed configuration covering a sharpened distal tip of a needle housed within the access cannula and a compressed configuration; and pressing the access cannula distally against the stomach wall until the access cannula moves toward the uncompressed configuration, wherein in the compressed configuration the access cannula is compressed along its longitudinal axis to expose the sharpened distal tip of the needle, thereby puncturing a portion of the stomach wall in which the access cannula is positioned with the sharpened distal tip; and moving the access cannula further distally relative to the endoscope so that the sharpened distal tip of the needle punctures the target wall of the target vessel, wherein upon puncturing the target wall of the target vessel the access cannula returns toward the uncompressed configuration and extends into the target vessel over the sharpened distal tip of the needle.

[0018] In one embodiment, the compressive force required to maintain the access cannula in the compressed configuration exceeds the compressive force exerted through the punctured target wall, such that the access cannula returns toward the uncompressed configuration upon puncturing the target wall of the target vessel, preventing the needle from damaging further distal walls of the target vessel.

[0019] In one embodiment, returning the access cannula to the uncompressed configuration increases the length of the access cannula within the target vessel, thereby securing the access cannula within the target vessel.

[0020] In one embodiment, the method further includes removing the needle from within the access cannula and inserting the guidewire through the access cannula such that the guidewire is inserted into the target vessel.

[0021] In one embodiment, the laser cutting pattern is selected to achieve a desired level of compressibility of the access cannula, the desired level of compressibility including the compressive force required to move the access cannula from the uncompressed configuration towards the compressed configuration and the shortened length of the access cannula when moved from the uncompressed configuration to the compressed configuration to prevent puncture of the target vessel. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 shows a longitudinal side view of a distal portion of a system in an uncompressed configuration according to an exemplary embodiment of the present disclosure. [Figure 2] FIG. 2 shows a longitudinal side view of the distal portion of the system according to FIG. 1 in a compressed configuration. [Figure 3] FIG. 3 shows a cross-section of the system according to FIG. 1 along line X. [Figure 4] FIG. 4 shows an enlarged longitudinal side view of the system according to FIG. 1 including a first exemplary laser cutting pattern. [Figure 5] FIG. 5 shows an enlarged longitudinal side view of the system according to FIG. 1 including a second exemplary laser cutting pattern. [Figure 6] FIG. 6 shows an enlarged longitudinal side view of the system according to FIG. 1 including a third exemplary laser cutting pattern. [Figure 7] 7 is a longitudinal side view of the distal portion of the system according to FIG. 1, showing the access cannula of the system in an uncompressed configuration and positioned against the wall of the organ. [Figure 8]8 is a longitudinal side view of the distal portion of the system according to FIG. 1, showing the access cannula in a compressed configuration so that the sharp tip of the needle is exposed to puncture the wall of the organ. [Figure 9] FIG. 9 is a longitudinal side view of the distal portion of the system according to FIG. 1, showing the sharp tip of the needle piercing the target wall of the target vessel. [Figure 10] FIG. 10 is a longitudinal side view of the distal portion of the system of FIG. 1, showing the access cannula returning toward its uncompressed configuration to move distally over the sharp tip of the needle to access the target vessel. DETAILED DESCRIPTION OF THE INVENTION

[0023] The present disclosure may be further understood with reference to the following description and the accompanying drawings, in which like elements are referred to by the same reference numerals. The present disclosure relates to an endoscopic needle system, and in particular to a variable exposure needle system for EUS procedures. Exemplary embodiments of the present disclosure comprise a system including an access cannula. The access cannula is configured to be longitudinally compressible to expose a sharp tip of a needle housed therein. The access cannula of these embodiments includes a cut pattern (e.g., laser cut) extending along a portion thereof, such that when the distal end of the access cannula is pressed against the wall of an organ and / or bile duct, the access cannula compresses to expose only a desired portion of the sharp tip of the needle, allowing a user to puncture the organ and / or duct wall against which the access cannula is pressed without puncturing further distal wall of the organ / duct.

[0024] While the exemplary embodiments specifically describe a needle system for accessing the bile duct, for example, for biliary drainage procedures, it will be understood by those skilled in the art that the exemplary system may be utilized for a variety of procedures in which it may be desirable to have a compressed access cannula, control the puncture distance, or have the sharp tip exposed only when in contact with tissue. As used herein, the terms "proximal" and "distal" are intended to refer to directions toward (proximal) and away from (distal) the user of the device (e.g., physician).

[0025] As shown in FIGS. 1-10 , a needle access system 100 for treating, for example, a bile duct according to an exemplary embodiment of the present disclosure includes an access cannula 102 and a needle 104 housed within the access cannula 102. The access cannula 102 includes a pattern 106 of apertures (e.g., a laser cut pattern) extending along a distal portion 108 of the access cannula 102. The pattern 106 is configured to permit longitudinal compression of the access cannula 102, such that the access cannula 102 is operable between an uncompressed configuration (as shown in FIG. 1 ) in which a sharp tip 110 of the needle 104 is housed within the distal portion 108, and a compressed configuration (as shown in FIG. 2 ) in which the length of the access cannula 102 is shortened to expose a selected length of the distal portion of the needle 104, including the sharp tip 110, for puncturing, for example, the wall of an organ and / or target duct. In an exemplary embodiment, system 100 is inserted into a target area within a patient's body, for example, through the working channel of a pre-placed endoscope.

[0026] The system 100 is inserted into a target area with the access cannula 102 in an uncompressed configuration and positioned adjacent a portion of tissue to be punctured (e.g., an organ wall, such as the stomach) to access the target duct. The access cannula 102, along with the needle 104, is pressed distally against the organ wall, compressing the distal portion 108 of the access cannula 102 against the organ wall. This moves the distal portion 108 of the access cannula 102 from the uncompressed configuration to the compressed configuration, exposing a desired length of the sharp tip 110.

[0027] The user may then push the exposed tip 110 (together with the access cannula 102) distally relative to the endoscope to puncture the wall of the organ. Once the tip 110 of the needle 104 punctures the wall of the organ, the access cannula 102 may be moved further distally to pass through the wall of the organ and puncture the proximal (target) wall of the target vessel. As described in further detail below, the system 100 is configured such that once the exposed tip 110 passes through the target vessel and compressive forces from the tissue are removed from the distal portion 108, the distal portion 108 expands from a compressed configuration toward an uncompressed configuration. That is, once the tip 110 of the needle 104 enters the vessel, the cannula 102 expands to cover the distal portion of the needle 104, preventing the tip 110 from puncturing further into the distal wall of the target vessel. Once the target wall of the vessel is punctured, the compressive force exerted on the access cannula 102 by the passed tissue is reduced, causing the access cannula 102 to return towards its uncompressed configuration and move distally into the target vessel, at least partially over the sharp tip 110.

[0028] Those skilled in the art will appreciate that the degree of reduction in compressive force exerted on the distal portion 108 of the access cannula 102 may vary depending on various factors, such as the nature (e.g., density) of the tissue through which the cannula 102 has passed, differences between tissues / disease states, the length of the distal portion 108 remaining within the tissue as the distal end of the cannula 102 enters the target vessel, etc., and that the return of the cannula 102 to its uncompressed configuration may not completely cover the sharp tip 110 of the needle 104. However, by reducing the length of the needle 104 exposed from the distal end of the cannula 102, the likelihood of penetrating / damaging further into the distal wall of the target vessel is significantly reduced. The needle 104 may then be removed from the access cannula 102. This allows other devices and / or tools, such as, for example, a guidewire, to be inserted into the target vessel via the access cannula 102.

[0029] The access cannula 102 extends along a longitudinal axis L from a proximal end (not shown) to a distal end 112. The access cannula 102 also includes a channel 114 extending therethrough. As described above, the distal portion 108 of the access cannula 102 includes a pattern 106 of apertures extending along the distal portion 108. This pattern 106 enables movement of the access cannula 102 between a biased, uncompressed configuration and a compressed configuration. As will be appreciated by those skilled in the art, the pattern 106 (e.g., the size and spacing of the apertures in the cannula 102 relative to the diameter of the cannula 102) can be selected to achieve a desired level of compressibility (i.e., the length to which the cannula 102 compresses when subjected to a level of force associated with penetrating tissue).

[0030] In an exemplary embodiment, the level of compressibility can be selected such that when access cannula 102 is actuated from the uncompressed configuration to the compressed configuration, access cannula 102 is shortened a distance selected to expose a desired length of needle 104 (e.g., tip 110) based, for example, on the size of the target vessel to be accessed. In particular, the length of this exposed tip 110 is such that after tip 110 pierces the proximal wall of the target vessel, the distal end of cannula 102 advances into the target vessel and distal portion 108 recoils to cover tip 110 before tip 110 pierces the further distal wall of the target vessel.

[0031] In an exemplary embodiment, pattern 106 can be selected to control the force required to compress access cannula 102 to the amount of compression (i.e., length) reduced in the access cannula, as described in further detail below. The compression force can be adjusted to be slightly less than the anatomy of the target vessel / structure to allow access cannula 102 to compress and expose sharp tip 110 of needle 104. The compression length is adjusted to correspond to or slightly below the target vessel / structure so as not to damage the distal wall of the target vessel / structure when needle 104 is inserted into the target vessel / structure. This can include designing spring forces or separate compression zones with different rates or hard stops, in one embodiment. In another embodiment, pattern 106 can create a variable compression rate between the uncompressed (e.g., relaxed) configuration and the compressed configuration.

[0032] In the exemplary embodiment, the pattern 106 includes a plurality of rows 116, each extending around the periphery (e.g., circumference) of the access cannula 102 and including a slot 118. Each row 116 is separated from an adjacent row 116 by a desired distance along the length of the access cannula 102. Each slot 118 extends along a corresponding one of the plurality of rows 116 around a selected portion of the circumference of the distal portion 108. Each slot 118 extends through a wall 120 defining the access cannula 102 such that the channel 114 is in open communication with the exterior of the access cannula 102 through the slot 118. In the exemplary embodiment, the plurality of rows 116 are spaced apart equidistantly along the length of the distal portion 108. However, it will be understood by those skilled in the art that, depending on the laser cut pattern 106, the plurality of rows 116 may not be spaced apart equidistantly, and in one embodiment, the spacing between the plurality of rows 116 may vary between two or more different distances.

[0033] In the exemplary embodiment, the rows 116 through which the slots 118 extend are generally perpendicular to the longitudinal axis L of the cannula 102. In one embodiment, each slot 118 is defined by a length (e.g., the extent of the slot along axis L) and a width (e.g., the distance around the circumference of the distal portion 108 through which the slot 118 extends). However, it will be understood by those skilled in the art that the access cannula 102 does not require each slot 118 to have the same dimensions, and that in other embodiments, the slots 118 may have variable dimensions to form a pattern 106 that achieves a desired level of compression. In the exemplary embodiment, each row 116 includes multiple slots 118 spaced equidistantly apart from one another within the row. However, it will be understood by those skilled in the art that any one row 116 may have one or more slots 118 with variable spacing, depending on the pattern 106.

[0034] As described above, the laser cut pattern 106 may be selected based on the desired compressibility of the access cannula 102. The laser cut pattern 106 determines the compressibility based on factors such as the number of slots 118 per row 116, the width and length of each slot 118, the rotation angle between slots 118 in adjacent rows 116, and the distance between rows 116. Each variable independently affects the compressibility of the access cannula 102. The dimensions (e.g., width, length) of the slots 118 determine how much each row compresses. For example, a wide, long slot 118 removes more material from the wall 120 of the access cannula 102 than a narrow, short slot 118 to allow for greater compression. In particular, a wider, longer slot 118 allows the portion of the access cannula 102 extending between the rows 116 more room to flex, thereby reducing the length of the access cannula 102 as it compresses longitudinally.

[0035] As will be appreciated by those skilled in the art, the rotation angle of slots 118 in adjacent rows 116 also affects the flexibility of the access cannula 102 and may be adjusted to achieve a desired compression of the access cannula 102. The rotation angle may be defined for a slot 118 in a first row of the plurality of rows 116 relative to a corresponding slot 118 in an adjacent second row of the plurality of rows 116, as the rotation of the slot 118 in the first row about the longitudinal axis L relative to the corresponding slot 118 in the second row. For example, when the slots 118 in adjacent rows 116 have a rotation angle of 90 degrees and the slots 118 have equal dimensions, the slots 118 in the first row 116 are offset from the slots 118 in the second row by an angle of 90 degrees about the longitudinal axis of the access cannula 102. In other words, the uncut portions 122 of the access cannula 102 between adjacent slots 118 alternate perpendicularly with each adjacent row 116.

[0036] 4-6 show examples of patterns 106 (e.g., laser cut patterns) that can be used to achieve various levels of compressibility. FIG. 4 shows a distal portion of an access cannula 102A including a laser cut pattern 106A, where each row 116A of the pattern 106A includes four equal slots 118A, with a rotation angle of approximately 45 degrees between adjacent rows 116A. FIG. 5 shows a distal portion of an access cannula 102B according to another exemplary embodiment. In the laser cut pattern 106B along the access cannula 102B, each row 116B of the pattern 106B includes two slots 118B, with a rotation angle of 90 degrees between adjacent rows 116B. As shown, the slots 118B of the laser cut pattern 106B are longer than the slots 118A of the laser cut pattern 106A shown in FIG. 3. Therefore, it can be understood by one skilled in the art that access cannula 102B will be longitudinally compressed to a greater degree than access cannula 102A when subjected to the same compressive force. Additionally, laser cut pattern 106B with a 90 degree rotation angle maximizes both the compressibility and flexibility of distal portion 108.

[0037] FIG. 6 illustrates a distal portion 108C of an access cannula 102C according to another embodiment. Similar to the access cannula 102B shown in FIG. 4, the access cannula 102C includes a pattern 106C in which each row 116C includes two slots 118C. However, rather than a 90-degree rotation angle between adjacent rows 116C, the laser-cut pattern 106C has an 85-degree rotation angle between adjacent rows 116C. Therefore, the laser-cut pattern 106C reduces the longitudinal flexibility and compressibility of the access cannula 102C relative to the access cannula 102B. However, it will be understood by those skilled in the art that the rotation angle between the rows can be selected and / or varied to independently adjust the flexibility and compressibility of the access cannula 102C, as desired.

[0038] It will be appreciated by those skilled in the art that the patterns 106A, 106B, and 106C shown in Figures 4-6, respectively, are exemplary only, and that the pattern 106 of the system 100 may assume any of a variety of configurations to achieve a desired level of compressibility and / or flexibility. In particular, the patterns enable movement of the access cannula 102 between an uncompressed configuration and a compressed configuration, during which the access cannula 102 is axially compressed along the longitudinal axis L by a desired distance. As exemplified by the embodiment illustrated in Figures 4-6, a desired level of compressibility and / or flexibility may be achieved by varying features such as the number of slots 118 per row 116, the width and length of each slot 118, the rotation angle between slots 118 in adjacent rows 116, and the distance between rows 116 of the laser-cut pattern 106.

[0039] In an exemplary embodiment, the access cannula 102 is configured with a size and shape that allows it to be inserted, for example, through the working channel of an endoscope, and in some cases, is sufficiently flexible to allow it to be inserted through the tortuous paths of a body lumen through which a flexible endoscope travels. In one embodiment, the access cannula 102 is formed from a nitinol hypotube having superelastic properties and configured to move from an uncompressed configuration to a compressed configuration when subjected to a compressive force and return toward the uncompressed configuration upon release of the compressive force. In conjunction with the pattern 106, the properties of the access cannula 102 can be further fine-tuned by controlling how the nitinol is processed.

[0040] As will be appreciated by those skilled in the art, when Nitinol is subjected to strain, a phase change from austenite to martensite can be induced in the material, imparting superelasticity. The temperature at which Nitinol is fully austenitic can be controlled via heat treatment of the material to determine the desired behavior (e.g., stiffness or flexibility) of the material at that temperature (e.g., body temperature). While Nitinol may be used to further fine-tune the desired properties of access cannula 102, it will be appreciated by those skilled in the art that access cannula 102 may be formed from any of a variety of materials so long as it is configured to be operable between uncompressed and compressed configurations, as described herein.

[0041] According to another exemplary embodiment, a thin, flexible coating, jacket, sheath, or other covering may extend over at least the distal portion 108 through which the pattern 106 extends to increase the stiffness of the distal portion 108 and / or better control its compressibility based on the desired application of the system 100. In this embodiment, the coating, jacket, sheath, or other covering may allow compression of the access cannula 102 while preventing fluid communication through the slot 118 between the channel 114 and the exterior of the access cannula 102. In another exemplary embodiment, the coating, jacket, sheath, or other covering may be formed from multiple durometer materials to induce variable stiffness along a desired portion of the access cannula 102. Such a jacket or covering may be used in conjunction with the pattern 106 to achieve desired properties of the access cannula.

[0042] Also, while the exemplary embodiment describes pattern 106 being used to achieve a desired compressibility and / or flexibility of access cannula 102, pattern 106 may also be selected to achieve a desired echogenicity of access cannula 102. In particular, slots 118 may be formed through wall 120 to create surface features that increase echogenicity while optimizing visualization under ultrasound guidance, allowing a user to confirm that access cannula 102 is positioned against a desired portion of the wall of an organ and / or target vessel. However, it will be understood by those skilled in the art that access cannula 102 may include other surface features in addition to or in place of pattern 106 to facilitate visualization under ultrasound guidance.

[0043] The needle 104 extends longitudinally from a proximal end to a sharpened distal end 110 and is configured to have a size and shape that is receivable within the channel 114. The sharpened end 110 tapers toward a distal tip 124. The length of the needle 104 may correspond to the length of the access cannula 102 such that the needle 104 is substantially contained within the channel 114 of the cannula 102 when the distal portion 108 is in an uncompressed configuration. In an exemplary embodiment, the proximal ends of the needle 104 and the access cannula 102 are fixed to one another such that in the uncompressed configuration, only the distal tip 124 of the sharpened end 110 extends distally beyond the distal end 112 of the access cannula 102. Thus, when the access cannula is initially positioned against the wall of an organ / duct, the distal tip 124 engages the wall to prevent movement of the access cannula 102 when the access cannula 102 is pressed against the wall to apply a compressive force. In other words, the exposed distal tip 124 prevents the system 100 from sliding along the wall of the organ / vessel, allowing the user to stay on the target.

[0044] With the sharpened distal tip 124 partially exposed, the distal tip 124 may capture and begin piercing tissue, and once the tissue wall contacts the distal end 112 of the access cannula 102, the access cannula 102 may begin to compress while the sharpened tip 110 continues its movement into the tissue. However, in another embodiment, when the access cannula 102 is in the uncompressed configuration, the sharpened tip 110 may be fully retracted within the channel 114. The length of the needle 104 is selected so that upon compression of the access cannula 102, a desired length of the sharpened tip 110 is exposed to pierce the wall without piercing further the distal wall of the target vessel, for example, as described above.

[0045] According to an exemplary method, as shown in FIGS. 7-10 , to treat a bile duct using system 100, an insertion device, such as an endoscope, is inserted through a body lumen until the distal end of the insertion device is positioned in a target area of ​​the patient's body (e.g., within the patient's stomach proximate the target duct to be accessed). Once the endoscope is positioned as desired, system 100 in its uncompressed configuration is inserted through the working channel of the endoscope until distal end 112 of access cannula 102 extends from the working channel and contacts a desired site on the stomach wall 10 (e.g., along a portion of stomach wall 10 corresponding to the area of ​​target duct 12 to be accessed), as shown in FIG. 7 . As described above, in the exemplary embodiment, distal tip 124 of sharpened tip 110 of needle 104 protrudes slightly beyond distal end 112 of access cannula 102 when distal portion 108 is in the uncompressed configuration, such that distal tip 124 engages the desired site on the stomach wall 10 and secures the position of access cannula 102.

[0046] 8 , the access cannula 102 and needle 104 are then pressed distally against the stomach wall 10 until the access cannula 102 is moved from the uncompressed configuration toward the compressed configuration, exposing the sharp tip 110 for puncturing the stomach wall 10. As described above, as the access cannula 102 is moved toward the compressed configuration, the access cannula 102 is axially compressed along the longitudinal axis L, which shortens the access cannula 102 and allows the sharp tip 110 of the needle 104 to move distally relative to the endoscope, thereby puncturing the stomach wall 10.

[0047] Once the stomach wall 10 is punctured, the restraining force exerted against the distal end of the distal portion 108 is reduced or equalized to the compressive force of the access cannula 102, which follows the pointed tip 110 distally through the stomach wall 10. The pattern 106 is designed to compress a certain amount before the distal pushing force overcomes the force exerted through the stomach wall 10. The user may then continue to move the cannula 102 and needle 104 distally until the pointed tip 110 of the needle 104 punctures the proximal wall 14 of the target duct, as shown in FIG. 8 and 9, the sharp tip 110 remains exposed due to the resistance (compressive force) exerted on the distal portion 108 of the access cannula 102 by the stomach wall 10 and any other intervening tissue between the stomach wall 10 and the ductal wall 14 as the distal portion 108 passes through the stomach wall 10 and any other intervening tissue between the stomach wall 10 and the ductal wall 14. As will be appreciated by those skilled in the art, this compressive force may depend on factors such as the firmness, stiffness, and / or structure of the tissue.

[0048] As described above, the compressibility determined by the pattern 106 along the distal portion 108 of the access cannula 102 and the length of the pattern 106 along the distal portion 108 of the access cannula 102 and / or the length of the needle 104 is selected based on factors such as the diameter of the target vessel 12 so that the distal end of the distal portion 108 enters the target vessel 12 (i.e., when the resistance applied to the distal portion 108 drops as the distal portion 108 enters the lumen of the vessel 12) and the distal portion 108 can return toward its uncompressed configuration before the exposed pointed tip 110 enters the target vessel 12 and punctures a further distal wall 16 of the target vessel 12.

[0049] According to an exemplary embodiment, the compressed length of distal portion 108 is selected so that when tip 110 penetrates vessel wall 14 and enters vessel 12, the distal end of distal portion 108 enters vessel 12 and expands over needle 104 before tip 110 passes through a further distal wall 16 of target vessel 12. The material forming pattern 106 and access cannula 102 is configured such that when tip 110 punctures the proximal vessel wall 14, access cannula 102 returns toward its uncompressed configuration and extends distally into target vessel 12 over tip 110, as shown in FIG.

[0050] Once the target vessel is accessed by the access cannula 102, the needle 104 may be removed, leaving the access cannula 102 in place. It will be understood by those skilled in the art that puncturing the target vessel causes the access cannula to return to its uncompressed configuration, thereby increasing its length within the target vessel and securing it for passage of other devices therethrough. In an exemplary embodiment, for example, a guidewire may be threaded through the access cannula 102 and into the target vessel 12, such that a catheter or other device may be inserted over the guidewire to facilitate drainage of the target vessel. The methods described above are exemplary methods for facilitating drainage of the target vessel. However, it will be understood by those skilled in the art that the system 100 may be utilized in other applications in which a longitudinally compressible access cannula 102 may be desired.

[0051] Those skilled in the art will understand that changes can be made to the above-described embodiments without departing from the spirit of the present invention. It will also be understood that structural features and methods associated with one of the embodiments may be incorporated into other embodiments. It is therefore understood that the present invention is not limited to the particular embodiments disclosed, but rather, modifications are encompassed within the scope of the present invention as defined by the appended claims.

Claims

1. 1. A system for accessing the bile duct, comprising: an access cannula extending along a longitudinal axis from a proximal end to a distal end, the access cannula including a channel extending longitudinally therethrough, a distal portion of the access cannula including a laser cut pattern including a plurality of slots extending through a wall of the access cannula such that the access cannula is movable between a biased, uncompressed configuration and a compressed configuration compressed along the longitudinal axis; a needle extending longitudinally from a proximal end to a sharpened distal end, the needle being housed within the channel of the access cannula such that the sharpened distal end is covered by the access cannula when the access cannula is in the uncompressed configuration and is exposed for puncturing a wall of one of an organ and a target vessel when the access cannula is in the compressed configuration; A system comprising:

2. 2. The system of claim 1, wherein the laser cutting pattern includes a plurality of rows each extending around the circumference of the access cannula, each of the plurality of rows including at least one slot extending through the wall of the access cannula along a portion of the row, the channel of the access cannula being open and in communication with the exterior of the access cannula through the slot.

3. The system of claim 2 , wherein each row of the laser cut pattern extends perpendicular to the longitudinal axis of the access cannula.

4. 4. The system of claim 1, wherein the laser cutting pattern is selected to achieve a desired level of compressibility of the access cannula, the desired level of compressibility including the compressive force required to move the access cannula from the uncompressed configuration toward the compressed configuration and the shortened length of the access cannula as it moves from the uncompressed configuration toward the compressed configuration.

5. 5. The system of claim 4, wherein the desired level of compressibility achieved by the laser cut pattern is based on one of: a number of slots per row, a dimension of each of the slots, a rotation angle between corresponding slots in adjacent rows, and a distance between rows.

6. The system of any one of claims 1 to 5, wherein in the uncompressed configuration, the distal-most tip of the needle projects distally beyond the distal end of the access cannula.

7. 7. The system of claim 1, wherein when the access cannula is moved from the uncompressed configuration to the compressed configuration, the access cannula is shortened a distance corresponding to the sharpened distal end of the needle.

8. The system of claim 1 , wherein the length of the sharpened distal end of the needle exposed when the access cannula is in the compressed configuration is less than the length of the target vessel to prevent through-puncture.

9. The system of any one of claims 1 to 8, wherein the access cannula is formed from nitinol hypotube.

10. 1. A needle system for treating a bile duct, comprising: an access cannula configured with a size and shape for insertion through a working channel of an endoscope, the access cannula having a generally tubular body extending along a longitudinal axis from a proximal end to a distal end, a portion of the access cannula including a laser cut pattern, the laser cut pattern including a plurality of slots extending through a wall of the access cannula such that the access cannula is compressible along the longitudinal axis; a needle removably received within the access cannula and extending longitudinally from a proximal end to a sharpened distal end, the sharpened distal end being covered by the access cannula when the access cannula is in an uncompressed configuration and the sharpened distal end being exposed when the access cannula is in a compressed configuration; A needle system comprising:

11. The needle system of claim 10 , wherein the access cannula is biased toward the uncompressed configuration such that the access cannula is movable between the uncompressed and compressed configurations.

12. 12. The needle system of claim 10 or 11, wherein the laser cutting pattern includes a plurality of rows each extending around the circumference of the access cannula, each of the plurality of rows including at least one slot extending through the wall of the access cannula along a portion of the row, the channel of the access cannula opening to and communicating with the exterior of the access cannula through the slot.

13. 12. The needle system of claim 10 or 11, wherein the laser cutting pattern is selected to achieve a desired level of compressibility of the access cannula, the desired level of compressibility including the compressive force required to move the access cannula from the uncompressed configuration toward the compressed configuration and the length shortened when the access cannula is moved from the uncompressed configuration toward the compressed configuration.

14. 14. The needle system of claim 13, wherein the desired level of compressibility achieved by the laser cut pattern is based on (a) the number of slots per row, (b) the dimensions of each of the slots, (c) the rotation angle between corresponding slots in adjacent rows, and / or (d) the distance between rows.

15. The needle system of any one of claims 10 to 14, wherein the access cannula is formed from nitinol hypotube.

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