Endoscope ultrasound-guided puncture needle

Abstract

The puncture needle includes a hollow shaft having a lumen sized and shaped to slidably receive a guidewire therein; the shaft has a distal end that includes an angled surface that extends proximally and transversely from a sharp distal-most tip of the shaft to a beveled smooth region of the shaft that is proximal to and transverse to the sharp tip. The bevel smooth region is positioned to slidably engage a guidewire extending distally from the distal end of the needle such that when the guidewire is retracted proximally into the needle, the bevel smooth region slidably engages the guidewire to minimize wear to the guidewire.

Description

This is a divisional application of the patent application with the application number 202080081210.1 for an invention patent. Priority Statement

[0001] This invention claims the priority of U.S. Provisional Patent Application Serial No. 62 / 944,725, filed on December 6, 2019; the disclosure of which is incorporated herein by reference. Technical Field

[0002] The present invention relates to an endoscopic needle, and particularly to an endoscopic ultrasound (EUS)-guided puncture needle. Background Art

[0003] A hollow needle can be used in EUS-guided procedures to access a target anatomical structure, such as the intestinal lumen, and a guidewire can be introduced into the target anatomical structure through the needle lumen to, for example, guide a stent implantation procedure. When extending distally from the tip of the needle, the guidewire can bend in multiple directions at different points. For example, when a physician attempts to retract the guidewire into the needle, the guidewire may get stuck on the sharp edge or tip of the needle, which may strip the guidewire. The stripped material may remain in the anatomical structure and / or may expose the wire core of the guidewire and pose an electrical safety hazard. Summary of the Invention

[0004] The present invention relates to a puncture needle, which includes a hollow shaft having a lumen sized and shaped to slidably receive a guidewire therein; and a distal end including an angled surface that extends proximally and laterally from the sharpest distal tip of the shaft to a beveled smooth region of the shaft, the beveled smooth region being proximal to the sharp tip and transverse to the sharp tip, and the beveled smooth region being positioned to slidably engage a guidewire extending distally from the distal end of the needle such that when the guidewire is retracted proximally into the needle, the beveled smooth region slidably engages the guidewire to minimize wear on the guidewire.

[0005] In one embodiment, the distal end of the shaft includes a sharp cutting surface extending proximally from the sharp tip, and the beveled smooth region is positioned such that when a guidewire extending from the distal end of the needle along a bend is retracted into the needle in a desired direction relative to the needle, the surface of the guidewire forming a radially inner surface along the bend contacts the beveled smooth region of the needle.

[0006] In one embodiment, the distal end of the shaft includes a first sharp cutting surface extending from the farthest apex to a first transition portion and a second sharp cutting surface extending from the first transition portion to a second transition portion, the first sharp cutting surface extending at a first angle relative to the longitudinal plane of the shaft at the farthest tip and bending to a second angle relative to the longitudinal plane of the shaft at the first transition portion, and the second cutting surface having a third angle relative to the longitudinal plane of the shaft.

[0007] In one embodiment, the distal end of the shaft includes a third sharp cutting surface extending from the farthest tip to a third transition portion and a fourth sharp cutting surface extending from the third transition portion to a fourth transition portion. The third sharp cutting surface extends at a fourth angle relative to the longitudinal plane of the shaft at the farthest tip and bends to a fifth angle relative to the longitudinal plane of the shaft at the third transition portion. The fourth sharp cutting surface extends at a sixth angle relative to the longitudinal plane of the shaft.

[0008] In one embodiment, the first sharp cutting surface and the second sharp cutting surface are substantially symmetric with respect to the third sharp cutting surface and the fourth sharp cutting surface relative to the intermediate plane of the needle.

[0009] In one embodiment, the first angle is in a first range of 0 to 10 degrees, the second angle is in a second range of 20 to 50 degrees, and the third angle is in a third range of 10 to 30 degrees.

[0010] In one embodiment, the bevel smooth region is defined by a U-shaped surface having a midpoint proximal to and transverse to the sharp tip. The U-shaped surface has a curvature parallel to the transverse plane of the shaft at the midpoint.

[0011] In one embodiment, the bevel smooth region includes an outer bevel on the outer surface of the shaft and an inner bevel on the inner surface of the shaft.

[0012] In one embodiment, the shaft includes a feature extending along its distal portion that is configured to mechanically engage a corresponding feature of a guide wire inserted therein to hold the guide wire relative to the needle in a desired rotational orientation.

[0013] In one embodiment, the feature of the shaft includes a slot extending along a portion of the length of the needle and configured to receive a lug extending radially from the guide wire.

[0014] The present invention also relates to a puncture needle assembly, which includes an anchoring guide wire including a first orientation feature; and a puncture needle including a hollow shaft having a lumen sized and shaped to slidably receive the guide wire therein; and having a distal end including a cutting surface that extends proximally and transversely from the sharpest distal tip of the shaft to a bevel smooth region of the shaft, the bevel smooth region being proximal to and transverse to the sharp tip and being positioned to slidably engage the guide wire extending distally from the distal end of the needle such that when the guide wire is retracted proximally into the needle, the bevel smooth region slidably engages the guide wire to minimize wear on the guide wire. The puncture needle further includes a second orientation feature extending along its distal portion that is configured to mechanically engage the first orientation feature to hold the guide wire relative to the puncture needle in a desired rotational orientation.

[0015] In one embodiment, the second orientation feature includes a slot extending along a portion of the length of the needle, and the first orientation feature includes a lug projecting outwardly from the guidewire.

[0016] In one embodiment, the lug has a ramped section to facilitate engagement of the shaft and the lug such that when the needle is retracted proximally over the guidewire, the ramp engages the distal end of the slot such that the lug folds over and passes through the needle until the lug has cleared the distal end of the needle.

[0017] In one embodiment, the second orientation feature includes a slot extending along a portion of the length of the needle, and the first orientation feature includes a lug projecting outwardly from the guidewire, the lug being configured to be severed from the guidewire when the needle is withdrawn proximally over the guidewire.

[0018] In one embodiment, the guidewire has a nitinol core with a polymeric coating.

[0019] The invention also relates to a method that includes extending a guidewire distally out of the distal end of a puncture needle, the puncture needle including a hollow shaft having a lumen sized and shaped to slidably receive the guidewire therein, the distal end of the needle including a cutting surface that extends proximally and transversely from the sharpest distal tip of the shaft to a beveled smooth region of the shaft, the beveled smooth region being proximal and transverse to the sharp tip; retracting the guidewire proximally into the needle such that the beveled smooth region slidably engages the guidewire to minimize wear on the guidewire.

[0020] In one embodiment, the method further includes rotating the guidewire relative to the longitudinal axis of the puncture needle to position a bend in the guidewire such that a portion of the surface of the guidewire that forms the radially inner surface of the bend contacts the beveled smooth region when the guidewire is retracted into the needle.

[0021] In one embodiment, the guidewire is rotated under ultrasound guidance such that the distal bent end is bent away from a side of the needle, the distal tip of the needle being formed on that side of the needle.

[0022] In one embodiment, the distal end of the shaft includes a sharp cutting surface extending proximally from the sharp tip, the beveled smooth region being positioned such that when the guidewire extending out of the distal end of the needle along the bend is retracted into the needle in a desired direction relative to the needle, the surface of the guidewire that forms the radially inner surface along the bend contacts the beveled smooth region of the needle.

[0023] In one embodiment, the beveled smooth region is defined by a U-shaped surface having a midpoint proximal and transverse to the sharp tip, the U-shaped surface having a curvature at the midpoint parallel to a transverse plane of the shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1A puncture needle is shown having a distal end with a sharp distal tip for piercing a target anatomical structure and a plurality of machined surfaces shaped for smooth advancement and retraction of a guide wire.

[0025] Figure 2 A puncture needle having a coordinate system of the needle is shown Figure 1 is shown.

[0026] Figure 3 A cross - section of the distal end of the puncture needle at a first transition is shown Figure 1 is shown.

[0027] Figure 4 A cross - section of the distal end of the puncture needle at a second transition is shown Figure 1 is shown.

[0028] Figure 5 An exemplary guide wire used with the puncture needle is shown Figure 1 is shown.

[0029] Figure 6 Shown is Figure 1 the bevel portion of the distal end of the puncture needle.

[0030] Figure 7 Shown is a puncture needle having an exemplary guide wire extending therefrom Figure 5 is shown Figure 1 is shown.

[0031] Figure 8 Shown is Figure 7 a side view of the puncture needle and the guide wire, wherein the guide wire engages the inner bevel of the puncture needle.

[0032] Figure 9 Shown is Figure 8 a cross - sectional view of the puncture needle and the guide wire.

[0033] Figure 10 Shown is Figure 7 a side view of the puncture needle and the guide wire, wherein the guide wire engages the outer bevel of the puncture needle.

[0034] Figure 11 A puncture needle having a longitudinal slot and a guide wire having alignment lugs according to a second exemplary embodiment is shown.

[0035] Figure 12 Shown is Figure 11 the inclined edge of the alignment lug. Detailed Description

[0036] The present invention can be further understood with reference to the following description and drawings, in which like elements are denoted by like reference numerals. Exemplary embodiments describe a device having a needle with a smooth surface to facilitate the advancement or retraction of a guidewire without damaging the guidewire. The exemplary device may include means for aligning the guidewire within the needle such that the guidewire interacts with a smooth ground surface rather than a sharper edge defined in the tip of the needle.

[0037] Figure 1 The distal end of a puncture needle 100 is shown, the puncture needle 100 having a distal end 102 with a sharp distal tip 104 for piercing a target anatomical structure, and a plurality of machined surfaces shaped to facilitate the smooth advancement and retraction of a guidewire 150 into and out of the distal end 102. The needle 100 is formed as a hollow shaft 124 sized and shaped to slidably receive the guidewire 150 such that, as will be understood by those skilled in the art, the guidewire 150 can extend therethrough distally from the distal tip 102. The needle 100 may be formed of any suitable material, such as, for example, nitinol alloy, cobalt-chromium alloy, stainless steel, etc. The guidewire 150 may be configured to be bent multiple times on an insertion device such as an endoscope along a tortuous path that has passed through a natural body cavity, for example, to enter a target tissue structure. Additionally, the guidewire may be an anchoring guidewire having a shaped distal end that enables tissue anchoring.

[0038] In the present embodiment, as Figure 5 shown, the guidewire 150 has a bent end 152 in its unconstrained state that is preformed to present a bent shape having two bent segments 154, each bent through an angle of up to approximately 135 degrees in the same direction of curvature such that, when unconstrained, the distal tip of the guidewire 150 points in a direction that forms an angle of up to approximately 270 degrees with respect to the longitudinal axis of the portion of the guidewire 150 proximal to the bent end 152. However, guidewires having other curvatures may also be used. As will be understood by those skilled in the art, the guidewire 150 has sufficient flexibility such that the bent end 152 can conform to the path of the interior of the hollow shaft 124 when one or both of the bent segments 154 are withdrawn into the shaft 124. The guidewire 150 may have, for example, a nitinol core covered in a polymer coating.

[0039] When the curved end 152 of the guidewire 150 extends distally from the distal tip 102 of the needle 100, i.e., when the curved end 152 is not constrained by the inner diameter of the shaft 124, the distal tip 156 of the guidewire 150 returns to its unconstrained state. However, the guidewire 150 described herein is for exemplary purposes only, and any guidewire can be used with the puncture needle 100. For example, the guidewire can be bent at different points in different curvature directions and / or have more or fewer bends. Those skilled in the art will understand that a guidewire having a significant curvature at its distal end is most likely to be damaged when withdrawn into a conventional needle because the radially inner side of the curved end drags on the sharp end of the needle to re-enter the lumen of the needle. As those skilled in the art will understand, a guidewire having a preformed curved distal end is typically used as an anchoring guidewire. That is, this type of guidewire can be inserted into the target structure via a needle or other insertion device that keeps the curved distal end substantially straight. Additionally, the guidewire can have any desired configuration.

[0040] When the target structure has been entered, the guidewire 150 can be pushed distally from the needle 100 (or the needle 100 can be withdrawn proximally over the guidewire 150) to release the curved end 152 to assume its curved configuration. In this curved state, the guidewire 150 can no longer be withdrawn proximally through the hole through which it entered the target tissue structure and is thus anchored within the target structure. The needle 100 can then be withdrawn proximally over the guidewire 150, which can then be used to provide a passage for other therapeutic devices (such as a stent, etc.) to be inserted into the target structure over the guidewire 150.

[0041] When the procedure is complete, the needle 100 is again advanced distally over the guidewire 150 into the target structure. At this time, the guidewire 150 is withdrawn proximally into the needle 100, during which operation the contact between the lumen of the needle 100 and the wall of the guidewire 150 constrains the guidewire to return to the passage of the lumen of the needle 100. The needle 100, which receives the guidewire therein, can then be withdrawn from the body. The needle of this embodiment is designed to minimize or eliminate damage to the guidewire during the process of withdrawing the guidewire proximally into the needle lumen.

[0042] The opening at the distal end 102 of the needle 100 is defined by a plurality of machined surfaces that cut into the hollow shaft 118. The opening is defined by a first section 106, a second section 110, and a third section 116. As Figure 2 shown, relative to a needle coordinate system having a longitudinal axis A, a first transverse axis B, and a second transverse axis C, the sections are defined in the following manner, with these axes defining a first longitudinal plane AC, a second longitudinal plane BC, and a transverse plane AB.

[0043] The distal end 102 is at the origin of the needle coordinate system, i.e., the most distal point of the puncture needle 100 has a sharp distal tip 104 for penetrating tissue. In this embodiment, the opening at the distal end 102 of the needle 100 is substantially symmetric with respect to the distal tip 104, such that the first, second, and third segments on either side of the AC plane are mirror images of each other. The first segment 106 is defined by a first incision that extends proximally and laterally from the distal tip 104 into the cylindrical wall of the needle 100.

[0044] The first incision starts at the distal tip 104 at a first angle with respect to the BC plane, the first angle being between about 0 degrees and 10 degrees, i.e., substantially parallel to or nearly parallel to the BC plane, and gradually steepens to a second angle with respect to the BC plane at the first transition 108, as can be seen in Figure 1 and more clearly seen in Figure 8 For example, the second angle, i.e., the angle of the incision of the first segment 106 with respect to the BC plane at the first transition 108, can be between about 20 degrees and 50 degrees. Thus, the first incision produces a curved first segment 106 that progresses from a shallow angle at the most distal side that is nearly parallel to the longitudinal axis of the needle 100 to a deeper angle with respect to the longitudinal axis at the first transition 108. As described above, the first incision of this embodiment is substantially symmetric on both sides of the distal tip 104.

[0045] The second segment 110 is defined by a second incision that extends proximally and laterally from the first transition 108 to a second transition 112 and a third incision that extends only proximally from the second transition 112, i.e., substantially parallel to the BC plane, to a third transition 114. The second incision is at a third angle with respect to the BC plane, and the third angle remains substantially constant from the first transition 108 to the second transition 112. For example, the third angle, i.e., the angle of the second incision with respect to the BC plane, can be between about 10 degrees and 30 degrees. It should be noted that the second incision and the third incision are reflected on both sides of the needle 100. The cross-section of the needle 100 at the first transition 108 is shown in Figure 3 and the cross-section of the needle 100 at the second transition 112 is shown in Figure 4 which is the same as the cross-section of the needle 100 at the third transition 114.

[0046] As will be understood by those skilled in the art, without departing from the scope of the present invention, the first angle, the second angle, and the third angle can be different from the exemplary angles provided above. The shapes of the first segment 106 and the second segment 110 are configured to puncture or obtain tissue from a target site within a living body. Thus, the edges of the needle 100 produced by the first, second, and third incisions remain sharp.

[0047] The third section 116 is defined by a fourth incision extending proximally and transversely from the third transition section 114. The fourth incision is parallel to the A-axis throughout the incision and has a varying angle with respect to the AC plane, thereby forming a substantially U-shaped chamber in the third section 116. The fourth incision starts at the third transition section 114 at a fourth angle with respect to the AC plane, which can start at approximately ~0 degrees and gradually increase to ~90 degrees until the fourth incision reaches the midpoint 118, i.e., the farthest proximal point in the distal end 102 of the cut. The angle of the fourth incision at the midpoint is substantially parallel to the AB plane and orthogonal to the AC plane. It should be noted that the fourth incision is substantially symmetric with respect to the AC plane. Without any further machining, the fourth incision will create sharp edges on the inner and outer surfaces of the shaft 124.

[0048] During endoscopic procedures, such as procedures for inserting a stent or a rendezvous procedure, Figure 5 the guidewire shown, such as guidewire 150, can be introduced into the target anatomical space and pushed distally from the needle 100. This allows the guidewire 150 to return to its unconstrained curved configuration, thereby anchoring it in the target space. After the procedure has been completed and the guidewire 150 needs to be withdrawn from the body, the user inserts the needle 100 over the guidewire 150 until the distal tip 104 of the needle 100 enters the target space. Then, the user withdraws the curved end 152 of the guidewire 150 into the distal end 102 of the needle 100. As described above, if the guidewire 150 is pulled back into the needle 100 in a manner that drags it across the sharp tissue-cutting surface, the guidewire 150 may be damaged.

[0049] To mitigate the above risks, in an exemplary embodiment, after making the first, second, third, and fourth incisions, the needle 100 is further machined. As Figure 6 shown, the distal end 102 has an outer bevel 120 to smooth the sharp edge on the outer surface of the third section 116; and an inner bevel 122 to smooth the sharp edge on the inner surface of the third section 116, minimizing the effect of contact between these surfaces and the guidewire 150. The radius of curvature of the outer bevel 120 and the inner bevel 122 can be in the range of approximately 0” to 0.010”. Additionally, the outer bevel 120 and the inner bevel 122 each have a curvature of approximately 45 degrees to avoid creating new sharp edges. In another embodiment, the outer bevel 120 and the inner bevel 122 can be an outer diameter and an inner diameter, an outer chamfer and an inner chamfer, or an outer fillet and an inner fillet. Additionally, the third section 116 can have a combination of bevels, radii, chamfers, and fillets (e.g., the sharp edge on the outer surface is a fillet and the sharp edge on the inner surface is a bevel).

[0050] Figure 7 Shown with guidewire 150 Figure 1For the needle 100, the curved end 152 of the guide wire 150 extends distally from the distal end 102. Figures 8 to 10 An exemplary interaction between the guide wire 150 and the distal end 102 during retraction of the guide wire 150 is shown. In this embodiment, the guide wire 150 is curved around the B-axis of the needle, so as to ensure that when the guide wire 150 is withdrawn into the needle 100, it is pulled across the surface defined in the third section 116 of the distal end 102, rather than across the sharper surfaces of the first section 106 and the second section 110, respectively. As Figure 9 can be seen, the guide wire 150 is pulled across the smooth inner bevel 122, thereby reducing the risk of the guide wire 150 being stripped during retraction. As Figure 10 can be seen, when the radius of curvature of the guide wire 150 is very small, the interaction between the guide wire 150 and the bevels 120, 122 increases, such that the guide wire 150 can also be pulled across the outer bevel 120.

[0051] In order for the guide wire to contact only the beveled third section 116 rather than the sharp first section 106 or second section 110, it is necessary to ensure that the guide wire is properly rotationally aligned within the needle 100. In other words, during retraction, the curvature of the guide wire 150 must be oriented such that the curvature of the guide wire 150 extends generally within the AC plane, and the guide wire 150 is curved away from the side of the needle where the distal tip 104 is formed. If the guide wire has a more complex curvature (e.g., a curvature that extends in more than one plane), the user can rotate the guide wire 150 or the needle 100 relative to the other under ultrasound visualization such that the current section entering the needle 100 is oriented within the AC plane, as described above. Thus, when the guide wire 150 enters the needle 100, the guide wire 150 will always contact the third section 116.

[0052] The needle 100 and the guide wire 150 can have features for enhancing their visualization under ultrasound guidance, such that the surgeon can ensure proper alignment of the needle 100 and the guide wire 150 by monitoring the orientation of the elements. For example, the needle 100 and the guide wire 150 can be formed of echoic materials. However, retraction can also occur without direct visualization. Thus, proper alignment of the elements can be ensured in an alternative manner.

[0053] Figures 11 to 12Illustrated is a puncture needle 200 having a longitudinal slot 204 in its hollow shaft 202. The puncture needle 200 can be used with a guide wire 250 having radially outwardly projecting lugs 252 (e.g., welded or coated onto the guide wire 250) sized and shaped to travel in the longitudinal slot 204 as the guide wire 250 is pushed distally out of and retracted proximally into the needle 200. The transverse movement of the lug 252 is restricted by the slot 204. In other words, throughout the procedure, the interaction between the lug 252 and the slot 204 holds the guide wire 250 in a selected rotational alignment relative to the puncture needle 200.

[0054] In this embodiment, the slot 204 closes at the distal end 206 of the needle 200. However, in another embodiment, the slot 204 can be open at the distal end 206. Thus, it can be ensured that the curvature of the guide wire 250 interacts only with the beveled portion of the needle 200. Those skilled in the art will understand that the slot can be curved in a manner corresponding to the curvature of a more complex guide wire shape to ensure that during withdrawal of the guide wire 250 into the needle 200, the distal end of the guide wire 250 is always rotated into the desired alignment relative to the needle 200.

[0055] In some procedures, after the guide wire 250 has been anchored in the target anatomy, the needle 200 is pulled proximally away from the guide wire 250. If the lug 252 is not designed to allow the needle 200 to pass over it, the presence of the lug 252 can prevent such withdrawal of the needle 200. As those skilled in the art will understand, the lug 252 can be designed such that when the needle 200 is pulled proximally away from the guide wire 250, the lug 252 will break off. In another embodiment, the lug 252 can be designed to compress and pass through the distal end of the lumen of the needle 200 until it exits the distal end 206 of the needle 200. Subsequently, the needle 200 can be slid proximally away from the guide wire 250 and removed from the body. For example, the lug 252 can have a ramp section 254 facilitating folding on the leading edge of the lug 252 when it reaches the distal end of the slot 204 such that when the needle 200 is pulled proximally over the guide wire 250 and the lug passes under the portion of the needle 200 distal to the distal end of the slot 204, the lug 252 folds over the lumen of the needle 200 and is compressed therein.

[0056] Those skilled in the art will understand that the above embodiments can be varied without departing from the concepts of the invention. It should also be understood that the structural features and methods associated with one of the embodiments can be incorporated into other embodiments. Thus, it should be understood that the invention is not limited to the particular embodiments disclosed, but that modifications are also covered within the scope of the invention as defined by the appended claims.

Claims

1. A puncture needle, the puncture needle comprising: A hollow shaft having a lumen sized and shaped to slidably receive a guide wire therein; And having a distal end, the distal end including an angled surface that extends proximally and laterally from the sharpest distal tip of the shaft to a beveled smooth region of the hollow shaft, the beveled smooth region including an outer bevel on the outer surface of the hollow shaft and an inner bevel on the inner surface of the hollow shaft, and the beveled smooth region being positioned to slidably engage the guide wire extending distally from the distal end of the hollow shaft when the guide wire is retracted proximally into the puncture needle.

2. The puncture needle according to claim 1, wherein the distal end of the hollow shaft includes a sharp cutting surface extending proximally from the sharp tip, and the beveled smooth region is positioned such that when the guide wire extending from the distal end of the hollow shaft is retracted into the puncture needle in a desired direction relative to the puncture needle, the inner surface of the curved end of the guide wire is configured to contact the beveled smooth region of the puncture needle.

3. The puncture needle according to any one of claims 1 to 2, wherein the opening at the distal end of the hollow shaft is defined by a plurality of machined surfaces cut into the hollow shaft, the opening being defined by a first section, a second section, and a third section, Wherein the first section is defined by a first cut that extends proximally and laterally from the sharpest distal tip into the cylindrical wall of the puncture needle, the first cut starting at a first angle from the sharpest distal tip and tapering to a second angle and terminating at a first transition; Wherein the second section is defined by a second cut that extends proximally and laterally from the first transition to a second transition and a third cut that extends proximally from the second transition to a third transition, the second cut being at a third angle, the third angle remaining constant from the first transition to the second transition; and Wherein the edge of the hollow shaft formed by the first cut, the second cut, and the third cut remains sharp.

4. The puncture needle according to claim 3, wherein the third section is defined by a fourth cut that extends proximally and laterally from the third transition to the midpoint of the hollow shaft, the fourth cut starting at a fourth angle from the third transition and gradually increasing to about 90 degrees before the fourth cut reaches the midpoint, the midpoint being defined by the point closest to the proximal side in the cut distal end of the hollow shaft.

5. The puncture needle according to claim 4, wherein the opening at the distal end of the hollow shaft is centered relative to the sharpest distal tip such that the first cut and the second cut are substantially symmetric on both sides of the sharpest distal tip.

6. The puncture needle according to claim 3, wherein the second angle is different from the first angle.

7. The puncture needle according to claim 3, wherein the first angle is in a first range of 0 to 10 degrees, the second angle is in a second range of 20 to 50 degrees, and the third angle is preferably in a third range of 10 to 30 degrees.

8. The trocar according to claim 3, wherein the bevel smooth area is defined by a U-shaped surface formed in the third section, and preferably, wherein the fourth incision forms a U-shaped chamber in the third section.

9. The trocar according to any one of claims 1 to 8, wherein the hollow shaft is formed of one of nitinol alloy, cobalt-chromium alloy, and stainless steel.

10. The trocar according to any one of claims 1 to 9, wherein the hollow shaft includes a feature extending along a distal portion of the hollow shaft, the feature being configured to mechanically engage a corresponding feature of a guide wire inserted therein to maintain the guide wire in a desired rotational orientation relative to the trocar.

11. The trocar according to claim 10, wherein the feature of the shaft includes a slot extending along a portion of the length of the needle, and the corresponding feature of the guide wire includes a lug projecting outwardly from the guide wire, wherein the slot is preferably configured to receive the lug projecting outwardly from the guide wire.

12. The trocar according to claim 11, wherein the lug has a ramped section to facilitate engagement of the shaft and the lug such that when the needle is retracted proximally on the guide wire, the ramped section engages the distal end of the slot such that the lug folds over and passes through the needle until the lug has cleared the distal end of the needle.

13. The trocar according to any one of claims 11-12, wherein the lug is configured to be severed from the guide wire when the needle is withdrawn proximally on the guide wire.

14. The trocar according to claim 3, wherein the bevel smooth area is partially defined by an incision extending from the sharpest distal tip at a fourth angle to a third transition point, wherein the fourth angle gradually increases from approximately zero degrees at the distal end of the bevel smooth area to approximately 90 degrees at the proximal end of the bevel smooth area.

15. The trocar according to any one of claims 1-14, wherein the bevel smooth area is configured to minimize wear on the guide wire when the guide wire is retracted proximally into the trocar.

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