Ring incision knife capable of controlling knife outlet length

Abstract

The invention relates to a snare incision knife capable of controlling the knife outlet length. The snare incision knife comprises a knife head assembly, a conveying assembly and a handle assembly. The tool bit assembly comprises a tool bit and a mandrel, the mandrel can drive the tool bit to move axially and rotate circumferentially, and at least one first positioning part is arranged on the peripheral surface of the tool bit; the conveying assembly comprises a conveying catheter and a limiting catheter, the limiting catheter is arranged at the far end of the conveying catheter, and a second positioning part matched with the first positioning part in structure is arranged on the limiting catheter; the handle assembly is connected with the end part of the mandrel; when the tool bit is located at the far end of the limiting catheter, the circumferential rotation of the tool bit can enable the first positioning part and the second positioning part to be correspondingly matched in the circumferential direction and axially abut against each other, so that the axial position of the tool bit is locked; and when the first positioning part is separated from the second positioning part due to the circumferential rotation of the tool bit, the tool bit can axially move relative to the limiting guide pipe.

Description

Technical Field

[0001] The invention relates to the field of medical instruments for interventional surgery, and in particular to a snare cutter with controllable cutter length. Background Art

[0002] Endoscopic submucosal dissection (ESD) is a new minimally invasive treatment technology developed in recent years. It can completely remove early gastrointestinal cancer in one go under the endoscope, with the advantages of less trauma and faster recovery. Compared with traditional laparotomy and endoscopic mucosal resection (EMR), ESD surgery saves patients from the pain of laparotomy and the risk of organ resection, and can obtain complete tissue pathology specimens for analysis. It can also achieve a resection rate of more than 96% for tumors with large area, irregular shape, or combined with ulcers and scars.

[0003] Due to the slender structure of existing endoscopic electrosurgical knives, the blade head is easily affected by external forces and may be displaced, making it difficult to fix the blade head in a predetermined position. In this case, it is difficult for the operator to accurately control the initial position and cutting depth of the electrosurgical cut, which increases the difficulty and risk of the surgical operation and also affects the accuracy and safety of the operation to a certain extent.

[0004] Therefore, how to achieve precise control of the position of the endoscopic electrosurgical knife head and improve the accuracy and safety of electrosurgical cutting is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The invention discloses a snare cutting knife with controllable knife extension length, aiming to solve the technical problems existing in the prior art.

[0006] In one embodiment, the present invention provides a snare cutting knife with controllable knife extension length, comprising a knife head assembly, a conveying assembly and a handle assembly;

[0007] The cutter head assembly includes a cutter head and a core shaft, the core shaft can drive the cutter head to move axially and rotate circumferentially, and at least one first positioning portion is arranged on the outer peripheral surface of the cutter head;

[0008] The delivery assembly includes a delivery catheter and a limiting catheter, wherein the limiting catheter is arranged at the distal end of the delivery catheter, and a second positioning portion adapted to the structure of the first positioning portion is arranged on the limiting catheter;

[0009] The handle assembly is connected to the end of the mandrel;

[0010] When the cutter head is located at the distal end of the limiting catheter, the circumferential rotation of the cutter head can make the first positioning portion and the second positioning portion correspond to each other in the circumferential direction and abut against each other axially, so that the axial position of the cutter head is locked; when the circumferential rotation of the cutter head causes the first positioning portion to separate from the second positioning portion, the cutter head can move axially relative to the limiting catheter.

[0011] As a preferred technical solution, the first positioning portion is configured as a protruding structure provided on the outer peripheral surface of the cutter head, and the protruding structure extends outwardly in the radial direction of the cutter head;

[0012] The distal end of the limiting catheter is provided with a boss extending radially inward, and the second positioning portion is configured as a receiving groove arranged on the proximal end surface of the boss, and the receiving groove can abut against the distal end surface of the protruding structure. When the protruding structure is located in the receiving groove, the groove wall of the receiving groove can limit the axial movement and circumferential rotation of the protruding structure to lock the cutter head in a preset position.

[0013] As a preferred technical solution, the limiting structure is provided with an axial through hole connected to the inner cavity of the delivery catheter, the accommodating groove and the axial through hole are arranged along the circumferential direction, and the cross-sectional dimension of the axial through hole is larger than the maximum dimension of the cross-sectional dimension of the cutter head;

[0014] When the protruding structure and the accommodating groove are circumferentially staggered, the cutter head and the protruding structure can pass through the axial through hole and move axially.

[0015] As a preferred technical solution, the width of the raised structure along the circumference of the cutter head is less than half of the circumference of the outer peripheral surface of the cutter head, and the extended height of the raised structure is less than the gap between the cutter head and the inner wall of the limiting conduit.

[0016] As a preferred technical solution, the cross-section of the protrusion structure is rectangular, circular, elliptical, fan-shaped, triangular or other geometric shapes.

[0017] As a preferred technical solution, the shape of the accommodating groove is matched with the cross-sectional shape of the protruding structure, and the cross-sectional shape of the axial through hole is matched with the overall cross-sectional shape of the cutter head and the protruding structure thereon.

[0018] As a preferred technical solution, at least two protrusion structures are provided on the outer circumferential surface of the cutter head at intervals along the circumferential direction, at least two accommodating grooves are provided on the limiting structure at intervals along the circumferential direction, and the axial through hole is provided between the accommodating grooves.

[0019] As a preferred technical solution, at least two groups of protrusion structures are axially spaced apart on the outer circumferential surface of the cutter head. When the cutter head moves axially relative to the limiting guide tube, the multiple groups of protrusion structures can respectively cooperate with the accommodating grooves to lock the cutter head in different axial positions.

[0020] As a preferred technical solution, a marking portion for indicating the position of the raised structure is provided at the distal end of the cutter head, and the marking portion corresponds to the raised structure in the axial direction; by observing the position of the marking portion through an endoscope, the position of the raised structure relative to the accommodating groove can be determined.

[0021] As a preferred technical solution, the handle assembly includes a rotating wheel and an operating handle;

[0022] The rotating wheel can rotate 360 ​​degrees and is rotatably connected to the operating handle. The rotation of the rotating wheel is used to drive the cutter head assembly to rotate;

[0023] The operating handle can reciprocate in the axial direction, and the axial movement of the operating handle drives the cutter head assembly to move axially.

[0024] The technical solution adopted by the present invention can achieve the following beneficial effects:

[0025] The present invention mainly provides a snare cutter with controllable cutter length, which mainly includes a cutter head assembly, a conveying assembly and a handle assembly, wherein the cutter head assembly includes a cutter head and a core shaft, and the conveying assembly includes a conveying catheter and a limiting catheter, wherein the outer surface of the cutter head is provided with a protruding structure, and the inner wall of the limiting catheter is provided with a receiving groove adapted thereto, when the cutter head is located at the distal end of the limiting catheter, the circumferential rotation of the cutter head can make the protruding structure and the receiving groove correspond to each other in the circumferential direction, and abut axially, so that the axial position of the cutter head is locked, at which time the position of the cutter head can be accurately controlled and electrocuting can be performed, which is convenient for controlling the electrocuting depth and reducing the difficulty of the operation; when the circumferential rotation of the cutter head separates the protruding structure from the receiving groove, the cutter head can move axially relative to the limiting catheter, at which time the position of the cutter head can be controlled again. Furthermore, multiple groups of protruding structures can be arranged at intervals along the axial direction on the outer surface of the cutter head, which are used to lock the cutter head at different axial positions to achieve more accurate adjustment of the position of the cutter head. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments, which constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions explain the present invention and do not constitute improper limitations on the present invention. In the drawings:

[0027] Figure 1 It is a schematic diagram of the structure of an endoscopic electrosurgical knife in a preferred implementation manner of an embodiment of the present invention;

[0028] Figure 2 A schematic structural diagram of a cutter head assembly in a preferred implementation manner of an embodiment of the present invention;

[0029] Figure 3 A schematic diagram of the structure of a cutter head in a preferred embodiment of the present invention;

[0030] Figure 4 This is a schematic structural diagram of a handle assembly in a preferred implementation manner of an embodiment of the present invention;

[0031] Figure 5 This is a schematic structural diagram of a conveying assembly in a preferred implementation manner of an embodiment of the present invention;

[0032] Figure 6 This is a schematic structural diagram of a position limiting catheter in a preferred implementation manner of an embodiment of the present invention;

[0033] Figure 7 A three-dimensional diagram of a position limiting catheter in a preferred embodiment of the present invention;

[0034] Figure 8 A schematic diagram of the cooperation between the conveying assembly and the cutter head assembly in a preferred implementation manner of an embodiment of the present invention;

[0035] Fig. 9 It is a structural schematic diagram of a preferred implementation manner of an embodiment of the present invention when the cutter head and the protruding structure are located in the axial through hole;

[0036] Fig.10 A schematic structural diagram of a cutter head assembly in a preferred implementation manner of an embodiment of the present invention;

[0037] Fig.11 A schematic structural diagram of a cutter head assembly in a preferred implementation manner of an embodiment of the present invention;

[0038] Fig.12 A schematic diagram of the cooperation between the conveying assembly and the cutter head assembly in a preferred implementation manner of an embodiment of the present invention;

[0039] Fig.13 A schematic structural diagram of a protrusion structure in a preferred implementation manner of an embodiment of the present invention;

[0040] Fig.14 A schematic structural diagram of a protrusion structure in a preferred implementation manner of an embodiment of the present invention;

[0041] Fig.15 A schematic structural diagram of a protrusion structure in a preferred implementation manner of an embodiment of the present invention;

[0042] Fig.16 Schematic diagram of the structure of the protrusion structure in a preferred implementation manner of an embodiment of the present invention.

[0043] Description of reference numerals:

[0044] The cutter head assembly 10 , the cutter head 11 , the raised structure 111 , the marking portion 112 , the core shaft 12 , the conveying assembly 20 , the limiting conduit 21 , the boss 211 , the accommodating groove 212 , the axial through hole 213 , the conveying conduit 22 , the handle assembly 30 , the rotating wheel 31 , and the operating handle 32 . DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. In the description of the present invention, it should be noted that the term "or" is usually used in the sense of including "and / or", unless the content clearly indicates otherwise.

[0046] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or a magnetic connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0047] In particular, in the description of the present invention, those skilled in the art should understand that, unless otherwise clearly specified and limited, the terms "proximal end" and "distal end" are relative to the operator; the "proximal end" is the end of the snare cutter with controllable cutter length that is closer to the user in one-dimensional direction when being operated, and the "distal end" is the end of the snare cutter with controllable cutter length that is farther away from the user in one-dimensional direction when being operated. And those skilled in the art should understand that "far" and "proximal" do not refer to the three-dimensional space straight-line distance from the user.

[0048] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] There are some deficiencies in the structural design of the snare cutters currently on the market. First, during the operation, the doctor needs to adjust the position of the blade several times, but the existing structure lacks an effective limiting structure, which can easily cause safety hazards such as the blade accidentally coming out or being inserted too deeply. Secondly, when the existing snare cutters are moving axially, it is difficult to accurately control the movement distance of the blade due to the lack of a reliable limiting structure, which not only increases the difficulty of the surgical operation, but may also affect the accuracy and safety of the operation.

[0050] refer to Figure 1 — Fig.16 In order to solve the problems existing in the prior art, the embodiment of the present invention provides a snare cutter with controllable cutter length, which can be used in endoscopic resection of early-stage tumors and lesions of the digestive tract. Specifically, the snare cutter in this embodiment can enter the human body cavity through the working channel of the endoscope, perform resection operations on the gastrointestinal mucosa and submucosal lesion tissue, and use high-frequency current to stop bleeding at the resection site, so as to ultimately achieve the purpose of minimally invasive treatment.

[0051] like Figure 1 In one embodiment of the present invention, a snare cutter with controllable cutter length includes a cutter head assembly 10, a delivery assembly 20 and a handle assembly 30 from the distal end to the proximal end, wherein the cutter head assembly 10 is used to realize the surgical cutting function, the delivery assembly 20 is used to connect the cutter head assembly 10 and the handle assembly 30 and deliver high-frequency current to the cutter head assembly 10, and the handle assembly 30 is used to control the rotation and axial movement of the cutter head assembly 10.

[0052] like Figure 2 In a preferred embodiment, the blade assembly 10 includes a blade 11, a snare ring and a core shaft 12. The blade 11 is fixed to the distal end of the snare ring and can cut the target tissue when powered on. The proximal end of the snare ring is connected to the distal end of the core shaft 12, and the proximal end of the core shaft 12 is fixedly connected to the handle assembly 30. The core shaft 12 and the snare ring are both made of conductive metal wire, and the materials can be the same or different. The core shaft 12 extends in a straight line in the lumen of the conveying assembly 20, and can drive the blade 11 and the snare ring to move axially and rotate circumferentially. Further, the snare ring has a certain flexibility. After extending from the distal end of the conveying assembly 20, it can be radially opened and become an annular structure to surround the tissue to be removed. When it is pulled back to the proximal end, the snare ring can be partially contracted and enter the limiting catheter 21. By controlling the axial movement and rotation of the core shaft 12, the position and direction of the snare ring can be adjusted, thereby achieving accurate collection and removal of the target tissue.

[0053] In this embodiment, the specific structure and size specifications of the blade head 11, the snare ring and the core shaft 12 are no longer specifically limited. Technical personnel in this field can freely select appropriate structural forms and size parameters based on actual needs and specific application scenarios while satisfying the cutting and hemostasis functions.

[0054] like Figure 4 In a preferred embodiment, the handle assembly 30 includes a rotating wheel 31 and an operating handle 32. The rotating wheel 31 can rotate 360 ​​degrees and is rotatably connected to the operating handle 32. The rotation of the rotating wheel 31 is used to drive the cutter head assembly 10 to rotate; the operating handle 32 can move back and forth axially, and the axial movement of the operating handle 32 drives the cutter head assembly 10 to move axially.

[0055] In a preferred embodiment, the rotating wheel 31 is arranged at the front end of the operating handle 32. The doctor can use the thumb to turn the rotating wheel 31 to realize its rotation. The rotating wheel 31 is connected to the core shaft 12 through a transmission structure. When the rotating wheel 31 rotates, it can drive the core shaft 12 and the cutting head 11 to rotate at a corresponding angle, thereby adjusting the circumferential position of the cutting head 11; the operating handle 32 can slide forward and backward along its axial direction, and drive the core shaft 12 to move axially accordingly through the internal connection structure, thereby controlling the cutting head 11 to extend or retract the limiting catheter 21, and realizing the adjustment of the telescopic length of the cutting head 11. In this embodiment, the specific structural form of the rotating wheel 31 and the operating handle 32 is not specifically limited, and those skilled in the art can select a suitable structural form according to actual needs.

[0056] like Figure 5 In a preferred embodiment, the delivery assembly 20 includes a delivery catheter 22 and a limiting catheter 21. The proximal end of the delivery catheter 22 is connected to the handle assembly 30, and the limiting catheter 21 is arranged at the distal end of the delivery catheter 22. Both are hollow structures and together form an axially through passage for accommodating the insertion of the cutter head 11, the snare ring, and the core shaft 12. Preferably, the delivery catheter 22 and the limiting catheter 21 are both made of insulating materials to insulate and protect the cutter head 11 and the snare ring to prevent current leakage during surgery.

[0057] It should be noted that the specific sizes and specifications of the delivery catheter 22 and the limiting catheter 21 can be adjusted and selected according to actual usage requirements. Those skilled in the art can determine the appropriate size parameters based on specific surgical requirements and endoscope models, and no specific limitations are made here.

[0058] In a preferred embodiment, at least one first positioning portion is provided on the outer circumferential surface of the cutter head 11, and a second positioning portion adapted to the structure of the first positioning portion is provided on the limiting catheter 21. When the cutter head 11 is located at the distal end of the limiting catheter 21, the circumferential rotation of the cutter head 11 can make the first positioning portion and the second positioning portion correspond to each other in the circumferential direction and abut axially, so that the axial position of the cutter head 11 is locked; when the circumferential rotation of the cutter head 11 causes the first positioning portion to separate from the second positioning portion, the cutter head 11 can move axially relative to the limiting catheter 21. Based on the structural coordination of the first positioning portion and the second positioning portion, the doctor can lock and unlock the cutting head 11 by controlling the rotation of the cutting head 11: when the cutting head 11 needs to be fixed at a specific axial position, the cutting head 11 only needs to be rotated so that the first positioning portion corresponds to the second positioning portion, and the two abut against each other to lock the axial position of the cutting head 11; when the axial position of the cutting head 11 needs to be adjusted, the cutting head 11 is first withdrawn toward the proximal end, and then the cutting head 11 is rotated so that the first positioning portion is offset from the second positioning portion, and the locking state can be released, so that the cutting head 11 can move axially freely.

[0059] like Figure 3 , Figure 6 — Figure 8 In a preferred embodiment, the first positioning portion is configured as a protruding structure 111, such as a lug, disposed on the outer peripheral surface of the cutter head 11, and the protruding structure 111 preferably extends radially outwardly of the cutter head 11; the distal end of the limiting conduit 21 is provided with a boss 211 extending radially inwardly, and the second positioning portion is configured as a receiving groove 212 disposed on the proximal end surface of the boss 211, and the receiving groove 212 can abut against the distal end surface of the protruding structure 111. When the protruding structure 111 is located in the receiving groove 212, the groove wall of the receiving groove 212 can limit the axial movement and circumferential rotation of the protruding structure 111, so as to lock the cutter head 11 in a preset position.

[0060] Preferably, the arrangement of the boss 211 makes the inner diameter of the limiting conduit 21 here smaller than other parts, forming a step-like structure; the receiving groove 212 is opened on the end surface of the boss 211 facing the proximal end, and the depth, width and other dimensions of the receiving groove 212 need to be slightly larger than the corresponding dimensions of the protruding structure 111, so that the protruding structure 111 can be smoothly embedded in and out of the receiving groove 212. When the cutter head 11 rotates to a specific angle, the protruding structure 111 can be embedded in the receiving groove 212, and at this time, the proximal wall surface of the receiving groove 212 abuts against the distal surface of the protruding structure 111 to prevent the cutter head 11 from moving to the distal end; the side wall of the receiving groove 212 can limit the circumferential rotation of the protruding structure 111, thereby realizing all-round constraint on the position of the cutter head 11; further, the bottom of the receiving groove 212 can limit the radial position of the protruding structure 111 to prevent the cutter head 11 from moving in the radial direction. When the position of the cutter head 11 needs to be adjusted, the cutter head 11 is first moved proximally so that the protruding structure 111 is disengaged from the receiving groove 212, and then the cutter head 11 is rotated so that the circumferential positions of the protruding structure 111 and the receiving groove 212 no longer correspond to each other, thereby releasing the locked state.

[0061] like Fig. 9 In a preferred embodiment, at the distal end of the limiting conduit 21, on the same cross section as the receiving groove 212, the space outside the area where the boss 211 is located is configured as an axial through hole 213, and the axial through hole 213 is connected to the inner cavity of the limiting conduit 21, and the cross-sectional dimension of the axial through hole 213 is greater than the maximum dimension of the cross section of the cutter head 11. When the protruding structure 111 and the receiving groove 212 are staggered in the circumferential direction, the cutter head 11 and the protruding structure 111 can pass through the axial through hole 213 and further move to the distal end.

[0062] Preferably, the axial through hole 213 and the receiving groove 212 are arranged along the circumferential direction to ensure that when the cutter head 11 rotates to make the protruding structure 111 and the receiving groove 212 misaligned, the protruding structure 111 can be aligned with the axial through hole 213, so that the cutter head 11 and the protruding structure 111 can smoothly pass through the axial through hole 213.

[0063] In a preferred embodiment, the width of the protruding structure 111 along the circumference of the cutting head 11 is less than half of the circumference of the outer surface of the cutting head 11. Matchingly, the circumferential width of the accommodating groove 212 along the limiting guide tube 21 is less than half of the circumference of the inner side surface of the limiting guide tube 21 to ensure that there is enough space to configure the accommodating groove 212. For example, when a protruding structure 111 is configured on the outer surface of the cutting head 11, and a accommodating groove 212 and an axial through hole 213 are configured circumferentially at the far end of the limiting guide tube 21, the protruding structure 111 can occupy a maximum of half of the circumference of the outer surface of the cutting head 11 to ensure that the axial through hole 213 can be set in the remaining circumferential space at the far end of the limiting guide tube 21, and the size of the axial through hole 213 is larger than the size of the protruding structure 111 to ensure that it can meet the smooth passage of the protruding structure 111.

[0064] In a preferred embodiment, the radial extension height of the protruding structure 111 along the cutting head 11 is smaller than the gap between the cutting head 11 and the inner wall of the limiting tube 21, so as to ensure that when the protruding structure 111 is misaligned with the accommodating groove 212, the protruding structure 111 will not interfere with the inner wall of the limiting tube 21, thereby enabling the cutting head 11 to rotate smoothly in the limiting tube 21; at the same time, it also ensures that when the protruding structure 111 is aligned with the axial through hole 213, the cutting head 11 and its protruding structure 111 can pass through the axial through hole 213 freely without getting stuck due to excessive size.

[0065] In a preferred embodiment, at least two protrusion structures 111 are circumferentially spaced apart on the outer circumferential surface of the cutter head 11 , at least two accommodating grooves 212 are circumferentially spaced apart on the limiting structure, and the axial through hole 213 is disposed between the accommodating grooves 212 .

[0066] like Figure 8 and Fig. 9 When two protruding structures 111 are provided on the outer circumference of the cutter head 11, the two protruding structures 111 can be evenly arranged along the circumference of the cutter head 11, that is, they are spaced 180° apart from each other; correspondingly, two accommodating grooves 212 spaced 180° apart along the circumference are also provided at the distal end of the limiting guide tube 21, and two axial through holes 213 are formed in the area between the two accommodating grooves 212. When the cutter head 11 rotates 90°, the two protruding structures 111 can align with the two axial through holes 213 at the same time, so that the cutter head 11 can move axially; when the cutter head 11 continues to rotate 90°, the two protruding structures 111 can be embedded in the two accommodating grooves 212 at the same time to achieve locking.

[0067] like Fig.16When the outer circumferential surface of the cutter head 11 is provided with three protruding structures 111, the three protruding structures 111 can be evenly arranged along the circumference of the cutter head 11, and the cross section of the cutter head 11 is roughly fan blade-shaped or turbine-shaped; accordingly, the distal end of the limiting guide tube 21 is also circumferentially spaced with three accommodating grooves 212, and the circumferential gaps of the three accommodating grooves 212 and the middle part of the limiting guide tube 21 together form an axial through hole 213, and the axial through hole 213 is also roughly fan blade-shaped. When the cutter head 11 rotates 60°, the three protruding structures 111 can be aligned with the axial through hole 213, so that the cutter head 11 can move axially; when the cutter head 11 continues to rotate 60°, the three protruding structures 111 can be embedded in the three accommodating grooves 212 at the same time to achieve locking.

[0068] By setting up multiple protrusion structures 111, a more stable positioning effect can be provided, the force on a single protrusion structure 111 can be reduced, and the reliability of the structural matching between the cutter head 11 and the limiting guide tube 21 can be improved; at the same time, multi-point positioning can also better prevent the cutter head 11 from unexpected shaking or deflection during use.

[0069] like Fig.10 — Fig.12 In a preferred embodiment, at least two groups of protrusion structures 111 are axially spaced apart on the outer peripheral surface of the cutter head 11. When the cutter head 11 moves axially relative to the limiting guide tube 21, the multiple groups of protrusion structures 111 can respectively cooperate with the accommodating grooves 212 to lock the cutter head 11 in different axial positions.

[0070] When the cutter head 11 moves axially in the limiting catheter 21, the first group of protrusion structures 111 can cooperate with the receiving groove 212 to lock the cutter head 11 in the first axial position; when the cutter head 11 needs to be further advanced, the cutter head 11 is first rotated to disengage this group of protrusion structures 111 from the receiving groove 212 and pass through the axial through hole 213, and then the cutter head 11 is further advanced to the distal end to cooperate with the second group of protrusion structures 111 and the receiving groove 212, at which time the cutter head 11 is locked in the second axial position. By arranging multiple groups of protrusion structures 111 in the axial direction of the cutter head 11, the stability of each working position is guaranteed, and the function of multi-level depth adjustment is provided, thereby enhancing the flexibility and adaptability of the device when in use; at the same time, the doctor can select the appropriate working depth of the cutter head 11 according to the specific surgical needs.

[0071] like Fig.13 — Fig.16 In a preferred embodiment, the cross-section of the protruding structure 111 is rectangular, circular, elliptical, fan-shaped, triangular or other geometric shapes; the shape of the accommodating groove 212 is adapted to the cross-sectional shape of the protruding structure 111, and can also be configured as a corresponding rectangular, circular, elliptical, fan-shaped, triangular or other geometric shapes.

[0072] In a preferred embodiment, the cross-sectional shape of the axial through hole 213 is adapted to the overall cross-sectional shape of the cutter head 11 and the raised structure 111 thereon; when the cutter head 11 is provided with one raised structure 111, the axial through hole 213 may be fan-shaped, semicircular or elliptical; when the cutter head 11 is provided with two raised structures 111, the axial through hole 213 may be roughly rectangular or elliptical; Fig.16 When the cutter head 11 is provided with three or more protruding structures 111, the axial through hole 213 may be roughly in the shape of a fan blade or a turbine.

[0073] In a preferred embodiment, a marking portion 112 for indicating the position of the raised structure 111 is provided at the distal end of the cutting head 11. Specifically, a notch is provided at the distal end of the cutting head 11, and the notch corresponds to the raised structure 111 in the axial direction. That is, the circumferential position of the notch at the distal end of the cutting head 11 corresponds to the circumferential position of the raised structure 111. By observing the position of the marking portion 112 through an endoscope, the position of the raised structure 111 relative to the receiving groove 212 can be determined.

[0074] Specifically, since the protruding structure 111 is located at the matching position between the cutting head 11 and the limiting catheter 21, it cannot be directly observed during the operation. By setting a notch-shaped mark at the distal end of the cutting head 11, the doctor can clearly observe the position of the notch through an endoscope. When the position of the cutting head 11 needs to be adjusted, the cutting head 11 is rotated so that the notch is aligned with the position of the axial through hole 213. At this time, the protruding structure 111 will also be rotated accordingly to the axial through hole 213, so that the cutting head 11 can be moved axially. Similarly, when the cutting head 11 needs to be locked, the cutting head 11 is rotated so that the notch is aligned with the position of the accommodating groove 212, so as to ensure that the protruding structure 111 is accurately embedded in the accommodating groove 212.

[0075] In specific use, the snare cutter with controllable cutter length in any of the above embodiments is inserted into the patient's body through the working channel of the endoscope, and the diseased part is cut. During the cutting process, the doctor observes the notch position at the distal end of the cutter head 11 through the endoscope, and rotates the notch to align with the axial through hole 213 of the limiting catheter 21. At this time, the raised structure 111 on the cutter head 11 is also aligned with the axial through hole 213. The doctor can push or pull the cutter head 11 in the axial direction until the raised structure 111 reaches the required working position; then, the cutter head 11 is rotated to make the raised structure 111 disengage from the axial through hole 213 and embed into the receiving groove 212, thereby locking the cutter head 11 in the axial position. At this time, the position of the notch also shows that the raised structure 111 has been locked in the receiving groove 212, and the doctor can start the surgical operation. When the position of the cutter head 11 needs to be adjusted, repeat the above steps.

[0076] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A snare cutting knife with controllable knife length, characterized in that: It includes a cutter head assembly, a conveying assembly and a handle assembly; The cutter head assembly comprises a cutter head and a core shaft, wherein the core shaft can drive the cutter head to move axially and rotate circumferentially, and at least one first positioning portion is arranged on the outer peripheral surface of the cutter head; The delivery assembly comprises a delivery catheter and a position limiting catheter, wherein the position limiting catheter is arranged at the distal end of the delivery catheter, and the position limiting catheter is provided with a second positioning portion adapted to the structure of the first positioning portion; The handle assembly is connected to the end of the spindle; When the cutter head is located at the distal end of the limiting catheter, the circumferential rotation of the cutter head can make the first positioning portion and the second positioning portion correspond to each other in the circumferential direction and abut against each other axially, so that the axial position of the cutter head is locked; when the circumferential rotation of the cutter head causes the first positioning portion to separate from the second positioning portion, the cutter head can move axially relative to the limiting catheter.

2. The snare cutting knife with controllable cutting length according to claim 1, characterized in that: The first positioning portion is configured as a protruding structure disposed on the outer peripheral surface of the cutter head, and the protruding structure extends outwardly in the radial direction of the cutter head; The distal end of the limiting catheter is provided with a boss extending radially inward, and the second positioning portion is configured as a receiving groove arranged on the proximal end surface of the boss, and the receiving groove can abut against the distal end surface of the protruding structure. When the protruding structure is located in the receiving groove, the groove wall of the receiving groove can limit the axial movement and circumferential rotation of the protruding structure to lock the cutter head in a preset position.

3. The snare cutting knife with controllable cutting length according to claim 2, characterized in that: The limiting structure is provided with an axial through hole communicating with the inner cavity of the delivery conduit, the containing groove and the axial through hole are arranged along the circumferential direction, and the cross-sectional dimension of the axial through hole is larger than the maximum dimension of the cross-sectional dimension of the cutter head; When the protruding structure and the containing groove are circumferentially staggered, the cutter head and the protruding structure can pass through the axial through hole and move axially.

4. The snare cutting knife with controllable cutting length according to claim 3, characterized in that: The width of the protruding structure along the circumference of the cutter head is less than half of the circumference of the outer peripheral surface of the cutter head, and the extending height of the protruding structure is less than the gap between the cutter head and the inner wall of the limiting conduit.

5. The snare cutting knife with controllable cutting length according to claim 4, characterized in that: The cross section of the protruding structure is rectangular, circular, elliptical, fan-shaped, triangular or other geometric shapes.

6. The snare cutting knife with controllable cutting length according to claim 3, characterized in that: The shape of the accommodating groove is matched with the cross-sectional shape of the protruding structure, and the cross-sectional shape of the axial through hole is matched with the overall cross-sectional shape of the cutter head and the protruding structure thereon.

7. The snare cutting knife with controllable cutting length according to claim 3, characterized in that: At least two of the protrusion structures are provided on the outer circumferential surface of the cutter head at intervals along the circumferential direction; at least two of the accommodating grooves are provided on the limiting structure at intervals along the circumferential direction, and the axial through hole is provided between the accommodating grooves.

8. The snare cutting knife with controllable cutting length according to claim 3, characterized in that: At least two groups of the protrusion structures are axially spaced apart on the outer peripheral surface of the cutter head. When the cutter head moves axially relative to the limiting guide tube, the multiple groups of the protrusion structures can respectively cooperate with the accommodating grooves to lock the cutter head in different axial positions.

9. The snare cutting knife with controllable cutting length according to claim 3, characterized in that: The distal end of the tool head is provided with a marking portion for indicating the position of the protruding structure, and the marking portion corresponds to the protruding structure in the axial direction; by observing the position of the marking portion through an endoscope, the position of the protruding structure relative to the receiving groove can be determined.

10. The snare cutting knife with controllable cutting length according to claim 1, characterized in that: The handle assembly includes a rotating wheel and an operating handle; The rotating wheel can rotate 360 ​​degrees and is rotatably connected to the operating handle, and the rotation of the rotating wheel is used to drive the cutter head assembly to rotate; The operating handle can reciprocate in the axial direction, and the axial movement of the operating handle drives the cutter head assembly to move axially.

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