Tissue cutting instrument

Abstract

The invention relates to the technical field of medical instruments, in particular to a tissue cutting instrument. The tissue cutting instrument comprises a cutting piece and a control device, wherein the cutting piece comprises a cutting part, and a stretching part and a resetting part which are connected with the cutting part and are oppositely arranged; the control device comprises a shell and an operating mechanism at least partially arranged in the shell, the operating mechanism comprises a stretching sliding block and a resetting sliding block which are connected with the stretching part and the resetting part respectively, and the stretching sliding block and the resetting sliding block can axially slide relative to the shell. According to the tissue cutting instrument, if the cutting piece deforms in advance due to misoperation before an operation, the reset sliding block can be moved reversely, the reset sliding block slides in the axial direction of the shell so that the reset part can be pulled, then the cutting part can be driven to reset, and the situation that the instrument is scrapped due to misoperation of the cutting piece is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of medical instruments, and in particular to a tissue cutting instrument. Background Art

[0002] This section merely provides background information related to the present disclosure and is not necessarily prior art.

[0003] Heart failure is a complex clinical syndrome characterized by impaired ventricular filling or ejection function due to abnormal cardiac structure or function. Its main clinical manifestations are dyspnea and fatigue (limited activity tolerance), as well as fluid retention (pulmonary congestion and peripheral edema). Heart failure is a serious and terminal stage of various heart diseases with a very high incidence rate, so it has become a widely concerned cardiovascular disease.

[0004] Heart failure can be divided into diastolic heart failure and systolic heart failure. Among them, diastolic heart failure refers to the condition in which the ventricular relaxation and compliance are reduced under the condition of normal ventricular contractile function, resulting in reduced ventricular filling volume and increased filling pressure, thereby producing pulmonary circulation and systemic circulation congestion syndrome. Diastolic heart failure can cause increased pressure in the left atrium and pulmonary veins, hindering the normal flow of oxygenated blood. At present, the treatment of diastolic heart failure is mainly based on drug therapy, but clinical data show that the use of interventional devices to open a small hole in the atrial septum of patients with diastolic heart failure to form a shunt from left to right is beneficial to reduce the pressure in the left atrium of patients with diastolic heart failure and improve the symptoms of heart failure patients.

[0005] At present, there are two main ways to use interventional devices to open a small hole in the atrial septum: one is to first puncture the atrial septum tissue, then use a balloon to expand the puncture site to a larger size to form an opening of a certain size, and then withdraw the balloon to form an interatrial shunt. In this way, tissue rebound often occurs after the balloon is withdrawn, causing the opening to shrink or even close. Another treatment method is to first puncture the atrial septum tissue, and then implant a stent at the puncture site. There is an opening of a set size in the middle of the stent. The stent props the puncture site to form an opening on the atrial septum, and the stent is used to maintain the existence of the opening. In this method, the stent is an implant, which will undergo endothelialization, making the opening of the atrial septum easily covered and blocked by the endothelial membrane. That is, both of the above-mentioned opening methods have the risk of opening closure, resulting in poor patient prognosis.

[0006] Currently, some researchers are treating diastolic heart failure by cutting tissue to form a hole directly in the atrial septum. Some cutting devices use coils as cutting pieces and cut by tightening the coils. However, since the wire diameter of the coils is generally small and the coils are relatively soft, once an error occurs before the operation, the coils will be difficult to reposition, resulting in the scrapping of the device. Summary of the Invention

[0007] Based on this, it is necessary to provide a tissue cutting instrument that can solve the problem of misoperation.

[0008] A tissue cutting instrument includes a cutting member and a control device. The cutting member includes a cutting portion, a stretching portion connected to the cutting portion, and a reset portion. The stretching portion and the reset portion are oppositely arranged; the control device includes a housing and an operating mechanism at least partially disposed in the housing. The operating mechanism includes: a stretching slider connected to the stretching portion and axially slidable relative to the housing; and a reset slider connected to the reset portion and axially slidable relative to the housing; the stretching slider slides axially along the housing to drive the stretching portion to slide axially, thereby stretching the stretching portion to deform the cutting portion, and after the cutting portion is deformed, the reset portion is stretched to cause the reset slider to slide axially in the opposite direction relative to the stretching slider.

[0009] In one embodiment, the operating mechanism further includes an operating member and a transmission member. The operating member is connected to the stretching slider and is used to drive the stretching slider to slide axially along the housing. The transmission member is mounted on the housing and is movably connected to the stretching slider and the reset slider. The transmission member is used to drive the reset slider to slide axially in the opposite direction relative to the stretching slider under the drive of the stretching slider after the stretching slider drives the cutting portion to be completely deformed.

[0010] In one embodiment, a first rack is provided on the stretching slider, a second rack is provided on the reset slider, the transmission member is a transmission gear, the transmission gear is rotatably mounted on the housing and can rotate around its own central axis in the housing. Before the cutting portion is completely deformed, the transmission gear only meshes with the second rack. After the cutting portion is completely deformed, the transmission gear meshes with the first rack and the second rack at the same time.

[0011] In one embodiment, the first rack extends axially at the distal portion of the stretching slider and does not extend to the proximal portion of the stretching slider. In the initial assembly position, the transmission member is located between the proximal portion and the reset slider, and the transmission member meshes with the second rack.

[0012] In one embodiment, a mounting seat is provided on the housing. The mounting seat includes two mounting plates that extend axially and are radially spaced apart. The operating member includes a sliding portion. The proximal end of the stretching slider is connected to the sliding portion to form two avoidance grooves respectively located on both sides of the stretching slider. At least a part of the stretching slider is received between the two mounting plates, and the two avoidance grooves are respectively avoided from the two mounting plates.

[0013] In one embodiment, a first receiving groove is formed in each of the mounting plates. A gland is further disposed in the housing. The gland is connected to the mounting plate, and two second receiving grooves corresponding to the two first receiving grooves are formed in the gland. One end of the transmission member is received in the first receiving groove and the corresponding second receiving groove, and the other end is received in the other first receiving groove and the corresponding second receiving groove and is clamped by the mounting plate and the gland. The reset slider is received in the gland and is slidably connected to the transmission member.

[0014] In one embodiment, the tissue cutting instrument further includes a delivery catheter and a grasping member. Both the delivery catheter and the grasping member are connected to the control device. The grasping member can slide axially along the delivery catheter and is movably received in the delivery catheter. The grasping member is used to grasp the tissue to be cut into the delivery catheter, and the cutting member cuts the tissue to be cut received in the delivery catheter.

[0015] In one embodiment, the grasping member includes a grasping portion and a connecting portion connected to the grasping portion. The control device further includes a grasping driving assembly and a limiting member. The grasping driving assembly is connected to an end of the connecting portion away from the grasping portion, and the limiting member is connected to the grasping driving assembly. The limiting member is used to releasably lock the position of the grasping driving assembly so as to lock the relative position of the grasping member and the delivery catheter.

[0016] In one embodiment, a first set of teeth is provided on the housing. The limiting member includes: a limiting piece rotatably connected to the grasping driving assembly. The limiting piece includes a connected limiting portion and a pressing portion. A second set of teeth engageable with the first set of teeth is provided on the limiting portion; an elastic member having one end connected to the pressing portion and the other end connected to the sliding member. The elastic member is used to drive the pressing portion to move away from the grasping driving assembly so that the limiting portion can rotate relative to the grasping driving assembly and the second set of teeth can be disengagably engaged with the first set of teeth.

[0017] In one embodiment, both the first set of teeth and the second set of teeth include at least two sets of racks, and the number of racks of the first set of teeth is equal to the number of racks of the second set of teeth. The racks of the first set of teeth are arranged in a staggered manner, and the racks of the second set of teeth are arranged side by side.

[0018] In one embodiment, the limiting member includes a holding portion and a clamping portion connected to the holding portion. The clamping portion is detachably sleeved on the housing and is located at the distal end of the sliding member to prevent the sliding member from sliding towards the distal end of the housing.

[0019] In the tissue cutting instrument provided by the embodiment of the present invention, a stretching part and a reset part are respectively connected to opposite ends of the cutting part, the stretching part is connected to a stretching slider, the reset part is connected to a reset slider, and both the stretching slider and the reset slider can slide along the axial direction of the housing. When cutting tissue, the stretching slider can be moved, so that the stretching slider tightens the stretching part to deform the cutting part to cut the tissue. During the cutting process, when the cutting part is deformed to a certain extent, when the stretching slider continues to tighten the stretching part, it will pull the reset part in the opposite direction. Since the reset slider can also slide axially relative to the housing, during the movement of the reset part along with the deformed cutting part, it can drive the reset slider to move along the housing in the direction opposite to the stretching slider, so that the cutting action of the cutting piece will not be affected. If the stretching slider is misoperated before the operation and the cutting piece is deformed in advance, the reset slider can be moved in the reverse direction, and the reset slider slides axially along the housing to pull the reset part and then drive the cutting part to reset. The situation of instrument scrapping caused by misoperation of the cutting piece is avoided. At the same time, it is beneficial to perform preoperative trial operation on the tissue cutting instrument. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for description in the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0021] Among them:

[0022] Figure 1 is a schematic structural diagram of a tissue cutting instrument according to an embodiment of the present invention;

[0023] Figure 2 is Figure 1 an enlarged view of part A in

[0024] Figure 3 is a schematic structural diagram of a cutting piece according to an embodiment of the present invention;

[0025] Figure 4 is a cross-sectional view of a part of the structure of a tissue cutting instrument according to an embodiment of the present invention;

[0026] Figure 5 is an assembly schematic diagram of a cutting piece and a delivery catheter according to an embodiment of the present invention;

[0027] Figure 6 is an assembly schematic diagram of a part of the structure of a control device according to an embodiment of the present invention;

[0028] Figure 7 is an exploded view of a housing according to an embodiment of the present invention;

[0029] Figure 8 Explosion view of the lower housing, gland and operating mechanism according to an embodiment of the present invention;

[0030] Figure 9 Schematic structural diagram of a partial structure of the control structure according to an embodiment of the present invention;

[0031] Figure 10 Explosion view of a partial structure of the control device according to an embodiment of the present invention;

[0032] Figure 11 Cross-sectional view of a partial structure during the assembly of the limiting member, sliding member and housing according to an embodiment of the present invention;

[0033] Figure 12 Schematic diagram of a partial structure of the upper housing according to an embodiment of the present invention;

[0034] Figure 13 Schematic structural diagram of the limiting piece according to an embodiment of the invention;

[0035] Figure 14 Schematic diagram of a partial structure of the upper housing according to another embodiment of the present invention;

[0036] Figure 15 Schematic structural diagram of the limiting piece according to another embodiment of the present invention;

[0037] Figure 16 Schematic structural diagram of the control device according to another embodiment of the present invention;

[0038] Figure 17 Schematic structural diagram of the limiting member according to another embodiment of the present invention. Detailed implementation manners

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0040] In the description of the embodiments of the present invention, it should be noted that for the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., it is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the embodiments of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0041] In the description of the embodiments of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", "connection" should be understood in a broad sense. For example, it can be a fixed connection, a replaceable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium. It can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific situations.

[0042] In the field of interventional medical devices, generally, the end of a medical device implanted into the human body or animal body that is closer to the operator is called the "proximal end", and the end that is farther from the operator is called the "distal end", and the "proximal end" and "distal end" of any component of the medical device are defined based on this principle. The "axial direction" generally refers to the length direction of the medical device when it is being delivered, and the "radial direction" generally refers to the direction of the medical device that is not parallel to its "axial direction", and the "axial direction" and "radial direction" of any component of the medical device are defined based on this principle. The "circumferential direction" refers to the circumferential direction, that is, the direction around the axis of the lumen structure or cylinder.

[0043] Please refer to Figure 1 , an embodiment of the present invention provides a tissue cutting instrument 100, which is used to cut the atrial septum tissue to form a hole in the atrial septum, so as to treat diastolic heart failure. It can be understood that the tissue cutting instrument 100 is not limited to cutting the atrial septum tissue. In other embodiments, it can also be used to cut the tissue of other parts to form small holes.

[0044] Please continue to refer to Figure 1-2 , in one embodiment, the tissue cutting instrument 100 includes a cutting member 10 and a control device 20.

[0045] Among them, the cutting member 10 is used to cut the tissue to be cut, and the control device 20 is connected to the cutting member 10. The control device 20 is used to control the cutting member 10 to cut the tissue, so as to form a small hole at the target position.

[0046] Please continue to refer toFigure 1-2 In one embodiment, the cutting member 10 includes a cutting portion 110, a stretching portion 120 connected to the cutting portion 110, and a reset portion 130. The stretching portion 120 and the reset portion 130 are oppositely disposed at both ends of the cutting portion 110. One end of the stretching portion 120 is connected to the cutting portion 110, and the other end extends axially. One end of the reset portion 130 is connected to the cutting portion 110, and the other end extends axially. The ends of the stretching portion 120 and the reset portion 130 that are not connected to the cutting portion 110 are both connected to the control device 20. Among them, the stretching portion 120 is used to drive the cutting portion 110 to deform under the drive of the control device 20 to cut tissue, and the reset portion 130 is used to drive the cutting portion 110 under the drive of the control device 20 to adjust the cutting portion 110 to return to the position and shape in the natural state when the cutting portion 110 is deformed in advance (the natural state refers to the state after the tissue cutting instrument 100 is assembled and before it is used, or the state without being subjected to external force. The natural state below has the same meaning and will not be elaborated again).

[0047] In one embodiment, the proximal end of the stretching portion 120 is connected to a radio frequency power supply connector (not shown in the figure). The cutting portion 110 and the stretching portion 120 are both made of electrically conductive materials. During the operation, the radio frequency power supply connector is connected to an external radio frequency power supply so that the cutting portion 110 is charged when powered on for electrocuting. In this way, the stretching portion 120 not only plays a role in controlling the deformation of the cutting portion 110, but also plays a role in electrical connection to make the cutting portion 110 charged during cutting, which is beneficial to making the structure of the tissue cutting instrument 100 relatively compact. It can be understood that the conductive material can be a metal material, and the metal material includes but is not limited to nickel-titanium alloy, stainless steel, etc.

[0048] Please refer to Figure 3 In one embodiment, the cutting portion 110 includes two connected cutting lines 111. Each cutting line 111 is C-shaped and has an open end. The two cutting lines 111 are connected at the open end to form a closed coil. The closed coil has two opposite connection ends, and the two connection ends are recessed to form two recessed portions 112, so that the outer contour of the closed coil is similar to the outer contour of the number 8. The stretching portion 120 and the reset portion 130 are both linear. One end of the stretching portion 120 is connected to one recessed portion 112 of the cutting portion 110, and the other end extends towards the end close to the control device 20 to be connected to the control device 20. One end of the reset portion 130 is connected to the other recessed portion 112 of the cutting portion 110, and the other end extends towards the end close to the control device 20 to be connected to the control device 20. When the cutting portion 110 surrounds the tissue, the proximal end of the stretching portion 120 can be pulled to deform the two C-shaped coils 211 of the cutting portion 110 into a substantially linear shape to cut the tissue.

[0049] It can be understood that the cutting part 110, the stretching part 120 and the reset part 130 can be integrally formed. For example, a metal wire or other conductive wire is bent into two sections and shaped to form the cutting part 110. The metal wire or other wire extends linearly from one of the concave parts 112 of the cutting part 110 and is shaped so that the two straight metal wires or other wires form a stretching part 120 or a reset part 130 that is not in the same plane as the cutting part 110. Since the wire diameter of the metal wire or other wire is generally small, this integrally formed method is beneficial to avoid breaking the metal wire or other wire during connection and fixation, and improve reliability. Or, the cutting part 110, the stretching part 120 and the reset part 130 are non-integral structures, and the cutting part 110 and the stretching part 120 or the reset part 130 are fixedly connected or movably connected by methods mastered by those skilled in the art. Among them, the fixed connection can be to fix the stretching part 120 or the reset part 130 on the concave part 112 of the cutting part 110 by means of welding, bonding, etc. The movable connection can be a lap joint. For example, the wire is bent after passing over the concave part 112 of the cutting part 110 so that the stretching part 120 or the reset part 130 is lapped on the cutting part 110. In this embodiment, the material of the reset part 130 is not limited to conductive materials, and can also be other non-conductive materials. Or, the cutting part 110 and the stretching part 120 are integrally formed, and the reset part 130 and the cutting part 110 are non-integral structures.

[0050] Please continue to refer to Figure 3 , in an embodiment, a flexible sheath 140 can be additionally provided outside the stretching part 120 or the reset part 130 to further prevent the metal wire or other wire from breaking during the stretching process.

[0051] Please return to Figure 1 , in an embodiment, the tissue cutting instrument 100 further includes a delivery catheter 30, and the proximal end of the delivery catheter 30 is fixedly connected to the control device 20.

[0052] Please combine with Figure 2 , the cutting member 10 is connected to the delivery catheter 30. In the natural state, the cutting part 110 is located outside the delivery catheter 30, and the stretching part 120 and the reset part 130 extend along the axial direction of the delivery catheter 30. The projection of the cutting part 110 on a plane perpendicular to the axial center axis of the delivery catheter 30 surrounds or substantially surrounds the projection of the delivery catheter 30 on this plane.

[0053] Please refer to Figure 4, in one embodiment, two channels 310 are formed in the catheter wall of the delivery catheter 30. The two channels 310 extend along the axial direction of the delivery catheter 30, and the two channels 310 are symmetrically arranged with respect to the axial central axis of the delivery catheter 30. The stretching portion 120 and the resetting portion 130 respectively extend into one of the channels 310, and the cutting portion 110 is located outside the delivery catheter 30.

[0054] It should be noted that, in other embodiments, the channels 310 may also be omitted. In this case, the stretching portion 120 and the resetting portion 130 may extend axially in the inner cavity of the delivery catheter 30. However, by providing two channels 310 to receive the stretching portion 120 and the resetting portion 130 respectively, on the one hand, the channels 310 can stabilize the stretching portion 120 and the resetting portion 130, which is beneficial to keeping the cutting portion 110 outside the delivery catheter 30 and avoiding deformation of the cutting portion 110. On the other hand, since the stretching portion 120 extends in the channel 310, the charged stretching portion 120 can be isolated in the channel 310, avoiding interference with other components in the cavity of the delivery catheter 30.

[0055] Please continue to refer to Figure 4-5 , in one embodiment, in the natural state, both the stretching portion 120 and the resetting portion 130 are substantially perpendicular to the cutting portion 110. Moreover, the area enclosed by each cutting line 111 is greater than half of the cross-sectional area of the delivery catheter 30. The cutting portion 110 forms two concave portions 112, such that the stretching portion 120 and the resetting portion 130 extend into the delivery catheter 30. The two concave portions 112 of the cutting portion 110 overlap on the distal end face of the delivery catheter 30, while the remaining part of the cutting portion 110 is located outside the delivery catheter 30.

[0056] After the tissue cutting instrument 100 is delivered to the target position in the living body, the cutting portion 110 is located outside the delivery catheter 30, which is beneficial for the cutting portion 110 to surround the tissue to be cut, so as to achieve smooth cutting and ensure that the aperture size of the small hole formed after cutting meets the requirements. The shape of the cutting portion 110 of the cutting member 10 described above, the connection relationship between the cutting portion 110 and the stretching portion 120 and the resetting portion 130, and the connection relationship between the stretching portion 120 and the resetting portion 130 and the delivery catheter 30 are beneficial for ensuring that after the tissue cutting instrument 100 is delivered to the target position in the living body, the cutting portion 110 is located outside the delivery catheter 30, which is beneficial for avoiding misalignment of the cutting portion 110 and being unable to surround the tissue to be cut, so as to ensure the smooth progress of the operation.

[0057] Please refer to Figure 6, in one embodiment, the control device 20 includes a housing 210 and an operating mechanism 220 disposed at least partially within the housing 210. The operating mechanism 220 is connected to the stretching portion 120 and the reset portion 130, and is configured to control the stretching portion 120 or the reset portion 130 to slide axially along the housing 210 to cut tissue or adjust the cutting member 10 back to its position and shape in the natural state.

[0058] Please refer to Figure 7 , in one embodiment, the housing 210 includes a first outer shell 211 and a second outer shell 212. The first outer shell 211 and the second outer shell 212 are detachably connected. When the first outer shell 211 and the second outer shell 212 are connected, they enclose an accommodation cavity, and at least a part of the operating mechanism 220 is received in the accommodation cavity.

[0059] The housing 210 further includes a first locking member 213, and the first locking member 213 is detachably connected to the first outer shell 211 and the second outer shell 212 to achieve the detachable connection between the first outer shell 211 and the second outer shell 212.

[0060] It can be understood that in this embodiment, the first locking member 213 is sleeved on the ends of the first outer shell 211 and the second outer shell 212 and is in threaded engagement with both of them, thereby achieving the detachable connection between the first outer shell 211 and the second outer shell 212. In other embodiments, the first locking member 213 can also be sleeved on the ends of the first outer shell 211 and the second outer shell 212 and achieve the detachable connection between the first outer shell 211 and the second outer shell 212 through snap-fit. Additionally, the housing 210 may further include a second locking member 214, and the second locking member 214 is disposed axially opposite to the first locking member 213. The second locking member 214 can also be sleeved on the outside of the first outer shell 211 and the second outer shell 212 through threaded connection or snap-fit to achieve the detachable connection between the first outer shell 211 and the second outer shell 212. The assembly manner between the first locking member 213 and the first outer shell 211 and the second outer shell 212 may be the same as or different from the assembly manner between the second locking member 214 and the first outer shell 211 and the second outer shell 212.

[0061] Please return to Figure 6 , in one embodiment, the operating mechanism 220 includes a stretching slider 221 and a reset slider 222.

[0062] Among them, the stretching slider 221 is connected to the stretching portion 120 of the cutting member 10, and the stretching slider 221 is axially slidable relative to the housing 210. The reset slider 222 is disposed on the housing 210, the reset slider 222 is connected to the reset portion 130 of the cutting member 10, and the reset slider 222 is axially slidable relative to the housing 210.

[0063] The axial sliding of the stretching slider 221 along the housing 210 can drive the stretching part 120 to slide, thereby tightening the cutting part 110 and deforming the cutting part 110. After the cutting part 110 is completely deformed and the stretching slider 221 is continuously pulled to slide axially, the deformed cutting part 110 can drive the reset part 130 to slide, and then drive the reset slider 222 to slide axially in the opposite direction relative to the stretching slider 221 along the housing 210.

[0064] In the case where the cutting part 110 is deformed in advance, by pulling the reset slider 222 to slide relative to the housing 210 towards the end where the cutting part 110 is restored from deformation, the cutting part 110 can be adjusted to return to its natural state.

[0065] It should be noted that the complete deformation of the cutting part 110 means that the cutting part 110 is deformed to a certain extent. At this extent, when the cutting part 110 continues to be axially stretched by the stretching part 120, it can drive the reset part 130 to axially displace in the direction opposite to the movement direction of the stretching part 120.

[0066] Specifically in this embodiment, when the two C-shaped coils of the cutting part 110 are deformed into a substantially straight line and can cut tissue, and at the same time, when continuing to be stressed, they can drive the reset part 130 to axially displace in the direction opposite to the movement direction of the stretching part 120, this state is the state of complete deformation of the cutting part 110.

[0067] Please continue to refer to Figure 6 and in combination with Figure 8 In an embodiment, the operating mechanism 220 further includes an operating member 223 and a transmission member 224.

[0068] Among them, the operating member 223 is connected to the stretching slider 221. The operating member 223 is used to drive the stretching slider 221 to slide axially along the housing 210. The transmission member 224 is installed on the housing 210 and is movably connected to the stretching slider 221 and the reset slider 222. The transmission member 224 is used to drive the reset slider 222 to slide axially in the opposite direction relative to the stretching slider 221 along the housing 210 under the continuous drive of the stretching slider 221 after the stretching slider 221 drives the cutting part 110 to undergo complete deformation.

[0069] Such a setting makes the reset slider 222 form a follower of the stretching slider 221, so that the number of operable components of the control device 20 can be reduced on the premise of realizing its functions, thus facilitating operation.

[0070] It can be understood that in other embodiments, the transmission member 224 may also be omitted, and two operating members 223 are provided at the same time. The two operating members 223 are arranged in parallel in the radial direction of the housing 210. One operating member 223 is connected to the stretching slider 221, and the other operating member 223 is connected to the reset slider 222. In this way, in the case where the cutting part 110 is deformed in advance, the cutting part 110 can also be restored to the natural state by operating one operating member 223 connected to the reset slider 222. However, the same operating member 223 cooperates with the transmission member 224, so that the transmission member 223 is automatically linked with the stretching slider 221 and the reset slider 222 when the operating member 223 is displaced by a certain distance, so as to automatically restore the cutting part 110 to the natural state.

[0071] Please continue to refer to Figure 6-8 , in an embodiment, an operation window 2101 is formed on the housing 210. The operating member 223 includes a sliding portion 2231 and an operating portion 2232. Wherein, the sliding portion 2231 is axially slidably assembled with the housing 210. One end of the operating portion 2232 is connected to the sliding portion 2231, and the other end extends away from the sliding portion 2231 and protrudes out of the housing 210 through the operation window 2101.

[0072] In an embodiment, a slide rail 215 is provided on the second housing 212. The extending direction of the slide rail 215 is the same as the axial direction of the housing 210. A slider (not shown in the figure) is provided on the sliding portion 2231. The slider is slidably assembled with the slide rail 215, so as to realize the sliding assembly of the sliding portion 2231 and the housing 210.

[0073] In this embodiment, the sliding portion 2231 and the operating portion 2232 are integrally formed, and two operating portions 2232 are provided. The two operating portions 2232 are oppositely arranged on both sides of the sliding portion 2231, so that the sliding of the sliding portion 2231 is more stable. In other embodiments, the sliding portion 2231 and the operating portion 2232 can also be fixedly connected by means of gluing or welding, or detachably connected by means of snap connection. In other embodiments, only one operating portion 2232 may be provided.

[0074] Please continue to refer to Figure 8 , in an embodiment, a first rack 2211 is provided on the stretching slider 221, a second rack 2221 is provided on the reset slider 222, the transmission member 224 is a transmission gear, and the transmission gear is rotatably installed on the housing 210 and can rotate around its own central axis in the housing 210. Before the cutting part 110 is completely deformed, the transmission gear only meshes with the second rack 2221. After the cutting part 110 is completely deformed, the transmission gear meshes with the first rack 2211 and the second rack 2221 at the same time.

[0075] In other words, in this embodiment, when the cutting member 10 is in a natural state, the transmission gear only meshes with the second rack 2221. When cutting tissue, by retracting the stretching slider 221, during a neutral stroke W (see Figure 6 ), the sliding of the stretching slider 221 will not drive the reset slider 222 to slide in the reverse direction. That is, during this neutral stroke W, the stretching slider 221 will only tension the stretching portion 120 to deform the two C-shaped coils 211 of the cutting portion 110 into a substantially straight shape to cut the tissue. After the two C-shaped coils 211 of the cutting portion 110 are deformed into a substantially straight shape, when the stretching slider 221 is continuously retracted, the first rack 2211 will only then mesh with the transmission gear. Thereafter, under the transmission of the transmission gear, if the stretching slider 221 is continuously retracted, it will drive the reset slider 222 to move in the opposite direction to the stretching slider 221, so that the distal ends of the stretching portion 120 and the reset portion 130 will move in equal amounts in the opposite direction. Therefore, when the tissue cutting is completed or when the cutting portion 110 is deformed prematurely, the operating member 222 can be pushed forward to move the reset slider 222 and the stretching slider 221 to adjust the cutting portion 110 back to the position and shape in the natural state, which is beneficial for preoperative trial operation of the instrument and can avoid the instrument being scrapped due to premature misoperation. It can be understood that the cutting portion 110 is formed by shaping with a shape memory metal material, so it has a shape memory function. Therefore, after the reset portion 130 returns to the natural state, when the operating member 222 is continuously pushed forward, the cutting portion 110 can be automatically reset under its shape memory function.

[0076] In one embodiment, the first rack 2211 extends axially along the distal portion of the stretching slider 221, and the first rack 2211 does not extend to the proximal portion of the stretching slider 221. Before the cutting portion 110 is deformed, that is, when the stretching slider 221 is in the initial assembly position and has not slid yet, the transmission member 224 is located above the proximal portion of the stretching slider 221 and only meshes with the second rack 2221 of the reset slider 222. Thus, when the stretching slider 221 slides axially towards the proximal end, before the degree of deformation of the cutting portion 110 reaches the level where it can pull the reset portion 130 to slide axially towards the distal end, the transmission member 224 is always radially opposite to the portion of the stretching slider 221 where the first rack 2211 is not provided, and will not act on the second rack 2221, avoiding interference with the cutting tissue.

[0077] It can be understood that in other embodiments, the transmission member 224 can also be a screw slider or other elements that can drive the stretching slider 221 and the reset slider 222 to move in the opposite direction simultaneously.

[0078] Please continue to refer to Figure 7-8, in one embodiment, a mounting seat 216 is further provided on the second housing 212, and a gland 217 is also accommodated in the housing 210. The gland 217 is connected to the mounting seat 216 to provide a sliding groove for the sliding of the reset slider 222.

[0079] In one embodiment, a buckle 2161 is provided on the mounting seat 216, and a clamping groove 2171 is formed on the gland 217. The gland 217 and the mounting seat 216 are detachably assembled by the clamping connection of the buckle 2161 and the clamping groove 2171, so as to facilitate the installation of the reset slider 222. It can be understood that in other embodiments, the clamping groove 2171 may also be formed on the mounting seat 216, and the buckle 2161 may be provided on the gland 217. Alternatively, the mounting seat 216 and the gland 217 may also be fixedly connected by bonding or welding.

[0080] Please continue to refer to Figure 8 , in one embodiment, a first accommodation groove 2162 is further formed on the mounting seat 216, and the rotating shaft of the transmission gear is accommodated in the first accommodation groove 2162 to achieve rotational assembly with the housing 210. It can be understood that a second accommodation groove 2172 may be formed on the gland 217, and the second accommodation groove 2172 is disposed opposite to the first accommodation groove 2171. When the gland 217 is covered on the mounting seat 216, the rotating shaft of the transmission gear is also partially accommodated in the second accommodation groove 2172 to prevent the transmission gear from falling out of the mounting seat 216, and the rotation of the transmission gear can be made more stable.

[0081] It can also be understood that in order to avoid interference between the moving path of the sliding portion 2231 of the operating member 223 and the position of the mounting seat 216, an avoidance groove 22311 is further formed on the sliding portion 2231 to avoid the mounting seat 216.

[0082] In one embodiment, the mounting seat 216 includes two mounting plates 2163 extending axially and radially spaced apart, and the buckle 2161 is disposed on the mounting plate 2163. A first accommodation groove 2162 is formed in the middle of each mounting plate 2163, and the first accommodation grooves 2162 on the two mounting plates 2163 are radially opposite.

[0083] In one embodiment, the sliding portion 2231 is generally U-shaped, the stretching slider 221 is generally strip-shaped, and one end of the stretching slider 221 extends into the sliding portion 2231 and is connected to the bottom of the sliding portion 2231, so as to form two avoidance grooves 22311 on both sides of the stretching slider 221.

[0084] The stretching slider 221 is at least partially located between the two mounting plates 2163, and the proximal portions of the two mounting plates 2163 are located in the two avoidance grooves 22311 of the sliding portion 2231. The two mounting plates 2163 act as slide rails, and the sliding portion 2231 slides along the two mounting plates 2163, and the sliding is more stable.

[0085] In one embodiment, when the gland 217 is snap-fitted with the mounting plate 2163, there is a certain distance between the side of the gland 217 close to the mounting plate 2163 and the side of the mounting plate 2163 close to the gland 217, thereby forming an accommodation space (not marked in the figure). The reset slider 222 is substantially T-shaped in the radial direction and is partially accommodated in the accommodation space, so that the reset slider 222 can slide along the accommodation space, and the sliding is more stable.

[0086] Both ends of the transmission member 224 are respectively lapped on the bottom of the two first accommodation grooves 2162, and in the initial assembly position (in the initial assembly position, the cutting portion 110 is in a natural state, for example, in the state shown in Figure 5 ), the transmission member 224 is opposite to the proximal portion of the stretching slider 221 that does not have the first rack 2211. The reset slider 222 is accommodated in the gland 217, and the second rack 2221 meshes with the transmission member 224. When the clamping groove 2171 of the gland 217 is snap-fitted with the buckle 2161 of the mounting seat 216, the state that the second rack 2221 always meshes with the transmission member 224 is maintained.

[0087] In this setting method, the operating member 223 and the stretching slider 221 are restricted between the two mounting plates 2613, and the transmission member 224 is restricted in the first accommodation groove 2162 and the second accommodation groove 2172. The reset slider 222 is restricted between the transmission member 224, the mounting plate 2613 and the gland 217, so that the axial sliding of the operating member 223 and the stretching slider 221 is more stable and the meshing transmission between the first rack 2211 and the second rack 2221 and the rotating member 224 is more stable, thereby ensuring that the tissue can be cut smoothly and accurately and the cutting member 10 can automatically reset after cutting. Or, it can be ensured that the cutting member 10 can automatically reset in case of misoperation.

[0088] Please return to Figure 1-2 , in one embodiment, the tissue cutting instrument 100 further includes a grasping member 40. The grasping member 40 is connected to the control device 20, and the grasping member 40 is movably accommodated in the delivery catheter 30. The grasping member 40 is used to grasp the tissue to be cut into the delivery catheter 30, so that after cutting, the cut tissue can be accommodated in the delivery catheter 30 and transported out of the body through the delivery catheter 30 to avoid the cut tissue falling into the blood circulation system and causing embolism.

[0089] It can be understood that in other embodiments, the grasping member 40 can also be omitted and the tissue to be cut can be adsorbed into the delivery catheter 30 by negative pressure for the cutting member 10 to cut. However, compared with the negative pressure adsorption method, the setting of the grasping member 40 can fix the tissue to be cut more stably, so as to cut a hole with a good shape.

[0090] Please continue to refer to Figure 1-2 , in one embodiment, the grasping member 40 includes a grasping portion 410 and a connecting portion 420 connected to the grasping portion 410. The grasping portion 410 has an abutting surface 411 for abutting against the tissue, and the proximal end of the connecting portion 420 (i.e., the end of the connecting portion 420 that is not connected to the grasping portion 410) extends axially along the inner cavity of the delivery catheter 30 to be connected to the control device 20. By controlling the grasping driving assembly 230 (see Figure 9 , which will be described below), the connecting portion 420 can be slid axially along the inner cavity of the delivery catheter 30, so that the grasping portion 410 is pushed out of the delivery catheter 30. After the grasping portion 410 passes through the tissue, the abutting surface 411 of the grasping portion 410 abuts against the tissue, and then the control device 20 pulls the connecting portion 420 proximally to draw the tissue into the delivery catheter 30.

[0091] It can be understood that, in one embodiment, in the natural state, the grasping portion 410 is generally in a cage-like structure to grasp the tissue to be cut. In other embodiments, the grasping portion 410 may also be generally in a disc-like structure or a hemispherical structure or other shapes that can grasp the tissue to be cut in the natural state. The grasping portion 410 is a self-expanding structure. When the radial restraint on the grasping portion 410 disappears, the grasping portion 410 automatically returns to its natural state. The specific shape of the grasping portion 410 and the specific assembly relationship between the grasping portion 410 and the connecting portion 420 can be selected according to actual needs by those skilled in the art using technical means that can be achieved, and will not be elaborated here.

[0092] Please refer to Figure 9 , the control device 20 further includes a grasping driving assembly 230 and a limiting member 240. The grasping driving assembly 230 is connected to the proximal end of the connecting portion 420. The grasping driving assembly 230 is used to control the grasping member 40 to be movably received in the delivery catheter 30. The limiting member 240 is used to lock the relative position of the grasping member 40 and the delivery catheter 30. The limiting member 240 locks the relative position of the grasping member 40 and the delivery catheter 30 by restricting the axial displacement of the grasping driving assembly 230.

[0093] It can be understood that, in other embodiments, the limiting member 240 can also be omitted. However, the setting of the limiting member 240 enables the grasping member 40 to stably grasp the tissue to be cut in the delivery catheter 30 when the restriction of the limiting member 240 is not released. Compared with the need for the operator to hold the grasping driving assembly 230 by hand to prevent the tissue to be cut from detaching from the grasping member 40 under its own tension, the limiting member 240 can make the grasping member 40 grasp the tissue to be cut more stably. At the same time, it can also free the operator's hands and reduce the operation difficulty.

[0094] Please refer to Figure 9-10, in one embodiment, the grasping driving assembly 230 includes a sliding member 231 and a fixing member 232.

[0095] The sliding member 231 is sleeved on the housing 210 and can axially slide relative to the housing 210. The fixing member 232 is connected to the distal end of the connecting portion 420. The fixing member 232 is partially accommodated in the housing 210, partially extends out of the housing 210 and is connected to the sliding member 231. The axial sliding of the sliding member 231 along the housing 210 can drive the fixing member 232 to axially slide, thereby driving the connecting portion 420 to axially slide.

[0096] Please continue to refer to Figure 10 , in one embodiment, a sliding hole 2102 is formed in the housing 210. The fixing member 232 includes a main body portion 2321 and a connecting key 2322. The main body portion 2321 is accommodated in the housing 210. The main body portion 2321 is generally cylindrical. A through hole (not shown in the figure) extending axially is formed in the main body portion 2321. The proximal end of the connecting portion 420 of the grasping member 40 is accommodated in the through hole and fixed on the main body portion 2321. One end of the connecting key 2322 is connected to the main body portion 2321, and the other end extends toward the side where the sliding hole 2102 is located and extends to the outside of the housing 210 through the sliding hole 2102 to be connected to the sliding member 231. The sliding member 231 has a cavity with both ends open, so that the sliding member 231 can be sleeved on the housing 210 and can axially slide along the housing 210.

[0097] Please refer to Figure 10-11 , in one embodiment, a first cog 218 is provided on the housing 210, a locking window 2311 is formed in the sliding member 231, and the limiting member 240 includes a limiting piece 241 and an elastic member 242.

[0098] Among them, the limiting piece 241 is rotatably connected to the sliding member 231. The limiting piece 241 includes a connected limiting portion 2411 and a pressing portion 2412. A second cog 24111 that can engage with the first cog 218 is provided on the limiting portion 2411. The plane where the pressing portion 2412 is located forms a non-zero angle with the plane where the limiting portion 2411 is located. One end of the elastic member 242 is connected to the pressing portion 2412, and the other end is connected to the sliding member 231. The elastic member 242 is used to drive the pressing portion 2412 to move away from the sliding member 231 so that the limiting portion 2411 extends into the housing 210 from the sliding member 231, and the second cog 24111 and the first cog 218 can be disengagably engaged.

[0099] In the natural state, the elastic member 242 is in an uncompressed state or a partially compressed state. The elastic member 242 pushes up the pressing portion 2412, causing the limiting portion 2411 to align with the locking window 2311, so that the second cogs 24111 on the limiting portion 2411 engage with the first cogs 218 on the housing 210, achieving the limiting effect. When the limiting effect needs to be released, press the pressing portion 2412. The elastic member 242 changes from the uncompressed state to the compressed state, or from the partially compressed state to the further compressed state, so that the limiting portion 2411 tilts up, and the second cogs 24111 disengage from the first cogs 218, thereby releasing the limiting effect.

[0100] Please continue to refer to Figure 12-13 , in an embodiment, both the first cogs 218 and the second cogs 24111 only include a set of racks, and the tips of the teeth of the rack are inclined toward the proximal side of the housing 210. Thus, when the sliding member 231 is retracted, the rack has an inclined guiding effect. At this time, as long as the force for retracting the sliding member 231 is greater than the elastic force of the elastic member 242, the sliding member 231 can be retracted normally without pressing the pressing portion 2412. However, when the sliding member 231 is pushed forward, since the blocking surface of the rack is large and there is no inclined guiding effect, it is necessary to press the pressing portion 2412 to disengage the first cogs 218 from the second cogs 24111, so as to more conveniently receive the tissue into the delivery catheter 30, and prevent the sliding member 231 from moving forward under the action of the self-tension of the tissue against the elastic force of the elastic member 242, so that the tissue can be more stably accommodated in the delivery catheter 30.

[0101] Please continue to refer to Figure 14-15 , in another embodiment, both the first cogs 218 and the second cogs 24111 include two sets of racks, and the two sets of racks included in the first cogs 218 are arranged in a staggered manner, and the two sets of racks included in the second cogs 24111 are arranged side by side. With such an arrangement, during the process of retracting the sliding member 231, the second cogs 24111 will sequentially and staggeredly engage with a single tooth on each of the two sets of racks of the first cogs 218, so that the retraction accuracy of the sliding member 231 can be greater and the processing is more convenient. For example, the distance between the teeth of each of the two sets of racks of the first rack 218 is 2 mm. Since the two sets of racks are arranged in a staggered manner, when the sliding member 231 is retracted, the actual accuracy of its single retraction is 1 mm. Compared with directly setting a single rack with an accuracy of 1 mm, the multi-rack method is more convenient for processing while ensuring the accuracy. It can be understood that in other embodiments, the first cogs 218 and the second cogs 24111 may also include three or more sets of racks. When the number of racks included in the first cogs 218 is greater than or equal to 2, the racks are arranged in a staggered manner with each other, and the processing can be conveniently formed while ensuring the accuracy.

[0102] Referring to FIG. 16, in another embodiment, the limiting member 240 includes a holding portion 243 and a clamping portion 244 connected to the holding portion 243. Among them, the clamping portion 244 is detachably assembled with the housing 210. The clamping portion 244 is sleeved on the housing 210 and located at the distal end of the sliding member 231, so as to prevent the sliding member 231 from sliding distally under the action of the self-tension of the tissue.

[0103] It can be understood that when the tissue is grasped by the grasping member 40 and placed in the delivery catheter 30, the tissue itself has tension. Therefore, the tissue actually has a tendency to move out of the delivery catheter 30. Therefore, under the action of the self-tension of the tissue, if no limiting action is applied to the sliding member 231, the sliding member 231 will actually also have a tendency to move proximally to release the tissue. In this embodiment, by sleeving the clamping portion 244 on the housing 210 and located at the distal end of the sliding member 231, the clamping portion 244 can play a stopping role on the sliding member 231 to prevent the sliding member 231 from being driven by the tissue to slide distally without applying an external force. Therefore, the limiting member 240 in this embodiment can also play a good limiting role.

[0104] Please continue to refer to Figure 17 , in one embodiment, the clamping portion 244 is a snap ring with an opening. The specification of the snap ring is adapted to the housing 210, and the snap ring can be sleeved on the housing 210 through the opening.

[0105] Please continue to refer to Figure 16-17 , in one embodiment, two clamping portions 244 are connected to one holding portion 243. When the two clamping portions 244 are sleeved on the housing 210, the axial lengths covering the housing 210 are different, so that the operator can select different clamping portions 244 for clamping according to actual needs. In addition, a bayonet 2431 can be opened on the holding portion 243, so that two or more limiting members 240 can be assembled together through the bayonet 2431, and further the specifications of the selectable clamping portions 244 are more. In other embodiments, three or more clamping portions 244 can also be directly connected to the holding portion 243, which can also achieve the effect of enriching the specifications of the clamping portion 244.

[0106] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0107] The above-disclosed are only the preferred embodiments of the present invention. Of course, the scope of the rights of the present invention cannot be limited by this. Therefore, the equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. An organization cutting instrument, characterized in that, It includes a cutting member and a control device. The cutting member includes a cutting part, a stretching part connected to the cutting part, and a reset part. The stretching part and the reset part are arranged oppositely; the control device includes a housing and an operating mechanism at least partially arranged in the housing. The operating mechanism includes: A stretching slider, connected to the stretching part and axially slidable relative to the housing; and, A reset slider, connected to the reset part and axially slidable relative to the housing; The axial sliding of the stretching slider along the housing drives the axial sliding of the stretching part, thereby tightening the stretching part and deforming the cutting part. After the cutting part is deformed, it tightens the reset part and causes the reset slider to slide axially in the opposite direction relative to the stretching slider along the housing.

2. The tissue cutting instrument according to claim 1, wherein The operating mechanism further includes an operating member and a transmission member. The operating member is connected to the stretching slider and is used to drive the stretching slider to slide axially along the housing. The transmission member is installed on the housing and is movably connected to the stretching slider and the reset slider. The transmission member is used to drive the reset slider to slide in the opposite direction relative to the stretching slider under the drive of the stretching slider after the stretching slider drives the cutting part to be completely deformed.

3. The tissue cutting instrument according to claim 2, wherein, A first rack is arranged on the stretching slider, and a second rack is arranged on the reset slider. The transmission member is a transmission gear. The transmission gear is rotatably installed on the housing and can rotate around its own central axis in the housing. Before the cutting part is completely deformed, the transmission gear only meshes with the second rack. After the cutting part is completely deformed, the transmission gear meshes with the first rack and the second rack simultaneously.

4. The tissue cutting instrument according to claim 3, wherein The first rack extends axially at the distal part of the stretching slider and does not extend to the proximal part of the stretching slider. In the initial assembly position, the transmission member is located between the proximal part and the reset slider, and the transmission member meshes with the second rack.

5. The tissue cutting instrument according to claim 2, wherein An installation seat is arranged on the housing. The installation seat includes two axially extending and radially spaced installation plates. The operating member includes a sliding part. The proximal end of the stretching slider is connected to the sliding part to form two avoidance grooves respectively located on both sides of the stretching slider. At least part of the stretching slider is received between the two installation plates, and the two avoidance grooves are respectively avoided from the two installation plates.

6. The tissue cutting instrument according to claim 5, wherein, A first accommodation groove is opened on each installation plate. A gland is further arranged in the housing. The gland is connected to the installation plate, and two second accommodation grooves corresponding to the two first accommodation grooves are opened on the gland. One end of the transmission member is received in the first accommodation groove and the corresponding second accommodation groove, and the other end is received in another first accommodation groove and the corresponding second accommodation groove and is clamped by the installation plate and the gland. The reset slider is received in the gland and is slidably connected to the transmission member.

7. The tissue cutting instrument according to any one of claims 1-5, characterized in that, The tissue cutting instrument further includes a delivery catheter and a grasping member. Both the delivery catheter and the grasping member are connected to the control device. The grasping member can slide axially along the delivery catheter and is movably accommodated in the delivery catheter. The grasping member is used to grasp the tissue to be cut into the delivery catheter, and the cutting member cuts the tissue to be cut accommodated in the delivery catheter.

8. The tissue cutting instrument according to claim 7, wherein The grasping member includes a grasping portion and a connecting portion connected to the grasping portion. The control device further includes a grasping driving assembly and a limiting member. The grasping driving assembly is connected to an end of the connecting portion away from the grasping portion, and the limiting member is connected to the grasping driving assembly. The limiting member is used to releasably lock the position of the grasping driving assembly so as to lock the relative position between the grasping member and the delivery catheter.

9. The tissue cutting instrument according to claim 8, wherein A first set of teeth is provided on the housing. The limiting member includes: A limiting piece rotatably connected to the grasping driving assembly. The limiting piece includes a connected limiting portion and a pressing portion. A second set of teeth that can engage with the first set of teeth is provided on the limiting portion. An elastic member, one end of which is connected to the pressing portion and the other end is connected to the sliding member. The elastic member is used to drive the pressing portion to move away from the grasping driving assembly so that the limiting portion can rotate relative to the grasping driving assembly and the second set of teeth can be disengagably engaged with the first set of teeth.

10. The tissue cutting instrument according to claim 9, wherein, Both the first set of teeth and the second set of teeth include at least two sets of racks, and the number of racks of the first set of teeth is equal to the number of racks of the second set of teeth. The racks of the first set of teeth are arranged in a staggered manner, and the racks of the second set of teeth are arranged side by side.

11. The tissue cutting instrument according to claim 8, wherein, The limiting member includes a holding portion and a clamping portion connected to the holding portion. The clamping portion is detachably sleeved on the housing and is located at the distal end of the sliding member to prevent the sliding member from sliding towards the distal end of the housing.

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