CN116746981B

CN116746981B - Invasive instrument

Info

Publication number: CN116746981B
Application number: CN202311042829.3A
Authority: CN
Inventors: 陈关宝; 肖运鹏; 赵城城
Original assignee: Zhejiang Guichuang Medical Technology Co ltd
Current assignee: Zhejiang Guichuang Medical Technology Co ltd
Priority date: 2023-08-18
Filing date: 2023-08-18
Publication date: 2023-11-07
Anticipated expiration: 2043-08-18
Also published as: CN116746981A

Abstract

The application relates to an invasive instrument which comprises a functional element, a power supply, an overcurrent protection module, a driving motor and a flexible driving shaft, wherein the flexible driving shaft comprises an elastic spiral winding spring pipe section and a rigid metal pipe section, and the driving motor is connected with the functional element through the rigid metal pipe section and the elastic spiral winding spring pipe section in sequence. When the rotation resistance of the functional element is larger than a first preset resistance value, the elastic spiral winding spring tube section which is in spiral extension can be elastically deformed in torsion along the extension direction of the elastic spiral winding spring tube section. The rotation resistance that the functional element received and the drive current of driving motor are positive correlation and be one-to-one, and the power passes through overcurrent protection module electricity and connects driving motor, and when the rotation resistance that the functional element received was greater than the second and predetermines the resistance value, driving motor's drive current is greater than predetermineeing the current value, and overcurrent protection module can take place to break circuit to make driving motor stop output torque. The invasive instrument provided by the application is simple in design and high in safety.

Description

Invasive instrument

Technical Field

The application relates to the technical field of medical instruments, in particular to an invasive instrument.

Background

Endovascular treatment remains the first choice for peripheral vascular disease (e.g., acute deep venous thrombosis of the lower limb), and with the continued development of endoluminal devices, particularly the advent of various volume reduction techniques, significantly improves the success rate of treatment of complex peripheral vascular disease. The volume reduction is to reduce the load of the intracavity treatment by removing substances such as plaque, thrombus, hyperplasia intima and the like in the blood vessel, thereby realizing the expansion of the lumen volume. The volume reduction technique specifically comprises: directional plaque ablation, laser plaque ablation, mechanical thrombus removal, orbital plaque ablation, thrombus ablation, and the like.

Further, volume reduction requires the creation of percutaneous vascular intraluminal access and pathways, and then the delivery of invasive instruments including functional elements (such as rotary cutting blades, stirring basket, rotational milling assemblies, coil springs, etc.) into the vessel (otherwise known as target vessel lumens) to perform the intended function. When the functional element is subjected to a large resistance force, the invasive instrument needs to be stopped, but because the space of the inner cavity of the blood vessel is too small, a torque sensor is difficult to be arranged in the inner cavity of the blood vessel, so that the invasive instrument cannot stop rotating when being blocked, and human tissues such as the blood vessel can be damaged.

Disclosure of Invention

Accordingly, there is a need for an invasive instrument that is simple in design and highly safe.

The invasive instrument provided by the application comprises a functional element, a power supply, an overcurrent protection module, a driving motor and a flexible driving shaft, wherein the flexible driving shaft comprises an elastic spiral winding spring pipe section and a rigid metal pipe section, and the driving motor is connected with the functional element through the rigid metal pipe section and the elastic spiral winding spring pipe section in sequence. The elastic spiral winding spring tube section is in a spiral extension shape, and when the rotation resistance born by the functional element is larger than a first preset resistance value, the elastic spiral winding spring tube section can elastically twist and deform along the extension direction of the elastic spiral winding spring tube section. The rotation resistance that the functional element received and the drive current of driving motor are positive correlation and be one-to-one, and the power passes through overcurrent protection module electricity and connects driving motor, and when the rotation resistance that the functional element received was greater than the second and predetermines the resistance value, driving motor's drive current is greater than predetermineeing the current value, and overcurrent protection module can take place to break circuit to make driving motor stop output torque, wherein, the second is predetermineeing the resistance value and is greater than first predetermineeing the resistance value.

In one embodiment, the resilient spiral wound spring tube segment is formed of a helical wire having a rectangular cross-section.

In one embodiment, the cross-sectional width of the spiral metal wire of the elastic spiral spring tube section is defined as a, the cross-sectional thickness of the spiral metal wire of the elastic spiral spring tube section is defined as b, the pitch of the elastic spiral spring tube section is defined as c, the pitch of the elastic spiral spring tube section is defined as e, the gap of the elastic spiral spring tube section is defined as h, wherein e=a+h, the shear modulus of the elastic spiral spring tube section material is defined as G, the cross-sectional angle of the elastic spiral spring tube section is defined as Φ, the energy storage calibration parameter of the elastic spiral spring tube section is defined as θ, the polar moment of the cross-section of the elastic spiral spring tube section is defined as Ip, the torque received by the elastic spiral spring tube section is defined as T, and when the axial length of the elastic spiral spring tube section is equal to e, the torsion angle of the elastic spiral spring tube section is defined as γ0,

，

。

in one embodiment, the section of the coiled wire of the elastic spiral wound spring tube segment is trapezoidal or parallelogram in cross section.

In one embodiment, the over-current protection module comprises an over-current electronic protection element and a P-channel MOS transistor, the power supply is connected in series with the over-current electronic protection element and the driving motor in sequence to form a first branch, and the power supply is connected in series with the P-channel MOS transistor to form a second branch. When the current of the first branch is smaller than or equal to a preset current value, the over-current electronic protection element can be kept in a conducting state, the P-channel MOS transistor is connected with a high level, and the driving motor can normally operate. When the current of the first branch is larger than a preset current value, the over-current electronic protection element is in an off state, the P-channel MOS transistor is connected with a low level, and the driving motor stops running.

In one embodiment, the overcurrent protection module further includes an alarm element connected in series with the second branch, and when the P-channel MOS transistor is connected to a low level, the second branch is turned on, and the alarm element can issue an alarm.

In one embodiment, the over-current protection element is a self-healing fuse.

In one embodiment, the invasive instrument further comprises a housing and a circuit controller, the drive motor and the circuit controller are both disposed within the housing, and the circuit controller is capable of controlling the drive motor to be turned on and off.

In one embodiment, the elastic spiral winding spring tube section comprises a first winding spring section and a second winding spring section, the rigid metal tube section, the first winding spring section and the second winding spring section are coaxially arranged and are sequentially connected along the axial direction, the bending rigidity of the second winding spring section is smaller than that of the first winding spring section, the rigid metal tube section is connected with the driving motor, and the second winding spring section is connected with the functional element. The invasive instrument further comprises a self-lubricating sheath which is coated outside the rigid metal tube section, the first spring winding section and the second spring winding section.

In one embodiment, the first and second coiled spring segments are each formed of a coiled wire, the cross-sectional area of the coiled wire of the first coiled spring segment being greater than the cross-sectional area of the coiled wire of the second coiled spring segment.

In one embodiment, the pitch of the first wrap spring segment is greater than the pitch of the second wrap spring segment such that the stiffness of the first wrap spring segment is greater than the stiffness of the second wrap spring segment.

Compared with the prior art, when one end of the flexible driving shaft connected with the functional element is suddenly blocked/stopped, firstly, the response time Tb of the output torque of the flexible driving shaft close to one end of the functional element reaching a peak value can be greatly increased, so that the monitoring control part of the driving handle has enough risk to cope with the response time, and the risk of internal safety accidents is reduced. Further, by setting the overcurrent protection module, the driving motor is powered off and stopped, and the driving motor does not output torque any more, at this time, the output torque of the end, close to the functional element, of the flexible driving shaft is also reduced to zero rapidly, and the end, close to the functional element, of the flexible driving shaft is reversely twisted until the normal state is restored. Therefore, the pressure of the output torque of the flexible driving shaft, which is close to one end of the functional element, on the blood vessel is rapidly relieved, and the damage to human tissues such as the blood vessel caused by the fact that the driving motor continuously outputs a larger peak torque is effectively avoided, and the operation safety of the invasive instrument is further improved.

Further, because the volume of the inner cavity of the blood vessel is smaller, the difficulty of directly arranging the torque sensor in the blood vessel to detect the rotation resistance received by the functional element is larger. In addition, the application realizes the stop of the driving motor through the disconnection of the overcurrent protection module without setting a complex control system, thereby further reducing the design difficulty of the invasive instrument.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments or the conventional techniques of the present application, the drawings required for the descriptions of the embodiments or the conventional techniques will be briefly described below, and it is apparent that the drawings in the following descriptions are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

FIG. 1 is a schematic view showing an assembled structure of a thrombus removal system according to an embodiment of the present application;

FIG. 2 is a schematic view of a rotary tube assembly according to an embodiment of the present application;

FIG. 3 is a cross-sectional view of an elastic spiral wound spring tube segment according to one embodiment of the present application;

FIG. 4 is an enlarged view of a portion of an elastic spiral wound spring tube segment sleeved with a self-lubricating jacket according to one embodiment of the present application;

FIG. 5 is an enlarged view of a portion of an elastic spiral wound spring tube segment without a self-lubricating jacket according to an embodiment of the present application;

FIG. 6 is a cross-sectional view of another embodiment of an elastic spiral wound spring tube segment provided by the present application;

FIG. 7 is a schematic view of a part of an elastic spiral wound spring tube segment according to an embodiment of the present application;

FIG. 8 is a schematic view of an elastic spiral wound spring tube segment according to one embodiment of the present application;

FIG. 9 is a circuit diagram of a power supply and an over-current protection module according to an embodiment of the present application;

FIG. 10 is a driving current testing circuit diagram according to an embodiment of the present application;

FIG. 11 is a circuit diagram of an output torque test of a flexible drive shaft according to one embodiment of the present application;

FIG. 12 is a circuit diagram of a combined test of drive current of a drive motor and output torque of a flexible drive shaft according to an embodiment of the present application;

FIG. 13 is a schematic view of a rotary basket according to an embodiment of the present application;

FIG. 14 is a schematic view of a rotary basket according to another embodiment of the present application;

FIG. 15 is a schematic view of a cutting wire according to an embodiment of the present application;

FIG. 16 is an assembly view of a drive handle and flexible drive shaft in accordance with one embodiment of the present application;

FIG. 17 is an exploded view of a drive handle and flexible drive shaft according to one embodiment of the present application;

FIG. 18 is a cross-sectional view I of a drive handle and flexible drive shaft according to one embodiment of the present application;

FIG. 19 is a second cross-sectional view of the drive handle and flexible drive shaft of an embodiment provided by the present application;

FIG. 20 is a side view of a drive handle and flexible drive shaft according to one embodiment of the present application;

FIG. 21 is an assembly view of a fastening ring, a triangle connector and a flexible drive shaft according to an embodiment of the present application;

FIG. 22 is an assembled cross-sectional view of a balloon assembly and inner tube according to an embodiment of the present application;

fig. 23 is an enlarged view of fig. 22 at a;

fig. 24 is a schematic structural view of a suction tube assembly according to an embodiment of the present application;

FIG. 25 is a schematic diagram of a portion of the structure of FIG. 24;

FIG. 26 is a schematic diagram of a portion of the second embodiment of FIG. 24;

FIG. 27 is a schematic diagram of a 5mL syringe according to an embodiment of the present application;

FIG. 28 is a schematic diagram of a 20mL syringe according to an embodiment of the present application;

FIG. 29 is a schematic diagram of a 50mL syringe according to an embodiment of the present application;

FIG. 30 is a schematic view of an extension tube according to an embodiment of the present application;

FIG. 31 is a schematic view of a three-way valve according to an embodiment of the present application;

FIG. 32 is a schematic view showing a partial structure of a thrombus removal system according to an embodiment of the present application;

FIGS. 33-39 are schematic operational flow diagrams illustrating an example of the use of a thrombus removal system according to one embodiment of the present application;

FIG. 40 is a graph of output torque as a function of time for a flexible drive shaft near one end of a functional element in accordance with one embodiment of the present application;

FIG. 41 is a graph of output torque as a function of time for a flexible drive shaft adjacent one end of a functional element in accordance with another embodiment of the present application.

Reference numerals: 100. a rotating tube assembly; 110. an inner tube; 111. a locking head; 120. a flexible drive shaft; 121. an elastic spiral wound spring tube section; 1211. a first wrap spring segment; 1212. a second wrap spring segment; 1213. a third wrap spring segment; 122. a rigid metal tube section; 130. a functional element; 131. rotating the basket; 1311. a first rotor member; 1312. a second rotor member; 1313. cutting wires; 1314. a cage body; 1315. a limiting member; 140. a balloon assembly; 141. a tip leader; 1411. a metal guide wire; 1412. puncture-proof ball head; 1413. a winding spring; 1414. closing the ball head; 1415. a single-layer winding pipe; 142. a compliant balloon; 143. a balloon development ring; 144. the saccule supports the pipe fitting; 1441. an inflation inlet; 150. a self-lubricating sheath; 200. a suction tube assembly; 210. a dilator tube; 220. a dilator joint; 230. a suction catheter; 231. a suction tube developing ring; 232. a suction tube holder; 233. knob type Y valve; 234. a 5mL syringe; 235. a 20mL syringe; 236. a 50mL syringe; 237. an extension tube; 238. a three-way valve; 300. a drive handle; 310. a driving motor; 320. a power supply; 330. an overcurrent protection module; 331. an overcurrent electronic protection element; 332. a P-channel MOS transistor; 333. an alarm element; 340. a housing; 341. triangular grooves; 342. a fastening part; 350. a circuit controller; 360. the triangular connector; 370. a fastening ring; 380. a gear set; 390. a speed regulating knob; 410. a dynamic torque sensor; 420. a multimeter; 430. a power supply device; 440. a first connector; 450. and a second connector.

Detailed Description

In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present application, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

Further, volume reduction requires the creation of percutaneous intravascular access and pathways, and then the delivery of invasive instruments including functional elements (such as rotary cutting blades, stirring basket, rotational milling assembly, coil springs, etc.) into the vessel (otherwise known as the lumen of the vessel) to perform the intended function. In the existing operation process, when the rotating speed of the functional element is too slow, the removal efficiency of the thrombus blocks (including plaque, thrombus, intima hyperplasia and other substances) is too low, and when the rotating speed of the functional element is too fast, once the functional element receives larger resistance, the whole invasive instrument inevitably vibrates, so that the operation stability of the invasive instrument is influenced, and even the safety of the whole blood vessel is influenced.

As such, there is a high demand for safety and efficiency of invasive devices, i.e., it is desirable for invasive devices to be able to perform thrombo-reduction surgery quickly, efficiently, safely and smoothly.

In order to solve the above-mentioned technical problems, it is necessary to provide a thrombus removal system so that an invasive instrument can complete a thrombus volume reduction operation quickly, efficiently, safely and smoothly.

Specifically, referring to fig. 1-41, the present application provides a thrombus removal system, which includes a rotating tube assembly 100, a suction tube assembly 200, and a driving handle 300, wherein the rotating tube assembly 100 includes an inner tube 110, a flexible driving shaft 120, a rotating basket 131, and a balloon assembly 140, the driving handle 300 is connected to the rotating basket 131 through the flexible driving shaft 120, the flexible driving shaft 120 includes an elastic spiral coiled spring tube segment 121 and a rigid metal tube segment 122, and the driving handle 300 can drive the rotating basket 131 to rotate sequentially through the rigid metal tube segment 122 and the elastic spiral coiled spring tube segment 121, so that the rotating basket 131 can crush a thrombus (including a thrombus, a plaque, etc.) in a blood vessel, and the elastic spiral coiled spring tube segment 121 is in a spiral extension shape, and when the rotation resistance of the rotating basket 131 is greater than a first preset resistance value, the elastic spiral coiled spring tube segment 121 can elastically twist-deform along its own extending direction.

The inner tube 110 is sequentially arranged through the driving handle 300, the flexible driving shaft 120 and the rotary basket 131 are movably sleeved on the inner tube 110, one end, far away from the driving handle 300, of the inner tube 110 extends out of the rotary basket 131 and is communicated with the balloon assembly 140, and the balloon assembly 140 is used for anchoring the position of the thrombus removal system in a blood vessel. The aspiration tube assembly 200 is movably sleeved outside the rotation tube assembly 100 and is used for injecting thrombolytic agents and aspirating embolic fragments.

Firstly, the filling medium can be injected into the balloon assembly 140 through the inner tube 110, so that the balloon assembly 140 is beneficial to supporting the whole inner wall of the blood vessel, the thrombus cleaning system can be quickly and deeply in the blood vessel, and the cleaning efficiency of the thrombus cleaning system is improved to a certain extent.

Thereafter, thrombolytic agents may be injected into the blood vessel through the aspiration tube assembly 200 to decompose or loosen the thrombus within the blood vessel to some extent, thereby significantly improving the removal efficiency of the thrombus.

It is noted that, in general, the decomposition and cleavage of thrombus by activating fibrinolysis and converting plasminogen to plasmin which can dissolve thrombus is considered as one of the effective methods for treating thrombus to dredge blood vessels. For example, thrombolytic agents such as Streptokinase (SK), urokinase (UK), staphylokinase (SaK), recombinant t-PA (rt-PA) or Cathfflo activating enzyme are injected into a blood vessel segment to decompose and lyse thrombus.

Then, the driving handle 300 drives the rotary basket 131 to rotate through the rigid metal tube section 122 and the elastic spiral reed tube section 121 in sequence so as to rotationally cut the structures such as thrombus, plaque and the like in the blood vessel. And, when rotatory basket 131 receives certain rotation resistance (be greater than first default resistance value), elasticity spiral spring pipe section 121 can take place elasticity torsion deformation along self extending direction, and at this moment, elasticity spiral spring pipe section 121 can absorb certain external impact through self torsion deformation, avoids whole rotatory pipe assembly 100 to receive the impact and take place violently to shake, has guaranteed the operating stability of rotatory pipe assembly 100, simultaneously, has also avoided the blood vessel to receive the damage of thrombus clearance system.

In practice, as shown in fig. 40, it should be noted that, in fig. 40, there are three graphs, where a curve j is a graph of a function T of an output torque T of one end of a conventional driving shaft connecting functional element and time, a curve k is a graph of a function T of an output torque T of one end of a flexible driving shaft 120 connecting functional element 130 (including but not limited to a rotating basket 131) and a curve m is a graph of a function T of an output torque T of an oscillation center of the flexible driving shaft 120. The point a is an equilibrium state a in which a small torsion occurs due to a working resistance when the flexible drive shaft 120 of the present application is in normal operation (similarly, the point a+ is an equilibrium state a+ in which a working resistance occurs when the conventional drive shaft is in normal operation), and the point B is an equilibrium state B in which a large torsion occurs due to a large resistance when the flexible drive shaft 120 of the present application is in a stuck state (similarly, the point b+ is an equilibrium state b+ in which a working resistance occurs when the conventional drive shaft is in a stuck state). Comparing curve j with curve k, it can be seen that in curve j, the response time Ta of the output torque of the end of the drive shaft near the functional element reaching the peak value, and in curve k, the response time Tb of the output torque of the end of the flexible drive shaft 120 near the functional element 130 reaching the peak value is satisfied, and the response time Tb is significantly longer than the response time Ta.

It will be appreciated that by designing the resilient spiral spring tube segment 121 of the flexible drive shaft 120 to have a resilient torsional deformation characteristic (which may act to store and release energy), the resilient spiral spring tube segment 121 of the flexible drive shaft 120 may provide a substantial cushioning effect, and the response time Tb for the output torque of the flexible drive shaft 120 near the end of the functional element 130 to peak may be greatly increased when the flexible drive shaft 120 is stuck. The increase of the response time Tb can prevent the output torque of the flexible drive shaft 120 near one end of the functional element 130 from increasing sharply (i.e., the trend of the torque variation tends to be relatively gentle and the time for the output torque to reach the peak value is prolonged) when the functional element 130 is stuck (i.e., when the functional element 130 fixedly connected to the flexible drive shaft 120 is stuck with a foreign object such as an unexpected plaque), so that the monitoring control portion of the drive handle 300 has enough risk to cope with the response time, and the risk of an in-vivo safety accident is reduced. It will be appreciated herein that the resilient spiral wound spring tube segment 121 of the flexible drive shaft 120 is not only designed for power transfer between the drive motor 310 and the rotary basket 131 (one of the functional elements 130) but is also designed to delay the impact of peak torque on the rotary basket 131 or on the flexible drive shaft 120 from the drive motor 310 when a jerk occurs.

In one embodiment, the response time Tb is designed to be greater than 2 seconds, considering that a sufficient period of time should be reserved for the monitoring control portion of the drive handle 300 to take corresponding countermeasures or decisions.

Finally, the minced thrombus and plaque within the blood vessel is aspirated through the aspiration tube assembly 200.

It should be noted that the rotary tube assembly 100 for cutting the thrombus and the aspiration tube assembly 200 for the fluid passage are independent from each other.

It should be noted that the blocked-up bolus-like thrombus within the vessel segment impedes the thrombolytic agent's penetration profile, extends thrombolytic time and reduces thrombolytic effect, if the insufficiently thrombolytically treated liquid-bolus mixture is pumped out of the body by suction tube assembly 200 under negative pressure, then the potential risk is posed: the flexible thrombus occludes the suction tube assembly 200, preventing the smooth performance of the procedure.

From the above, the above arrangement finally achieves the purpose of efficiently and stably removing thrombus and plaque in the blood vessel.

Specifically, the flexible drive shaft 120 has an overall axial length of 50cm-200cm, and the flexible drive shaft 120 is sufficiently elastic or flexible to be able to produce a flexible bend having a radius of curvature of 5mm-60mm to perform the function of traveling in a complex human body structure or tortuous blood vessel. Further, at the radius of curvature described above, when the driving handle 300 drives the flexible driving shaft 120 to rotate at the operation speed, and the flexible driving shaft 120 is elastically deformed only, not plastically deformed.

In most use cases, the flexible drive shaft 120 does not have to have excessive elasticity or flexibility over its entire length, i.e. it is sufficient that the flexible drive shaft 120 only has to have a certain elastic bending property in a specific axial portion. Specifically, in one aspect, the flexibility and elasticity of the end of the flexible drive shaft 120 connected to the functional element 130 (including the rotating basket 131) is enhanced, which is beneficial for the flexible drive shaft 120 to drive the functional element 130 to bend and travel in the tortuous vascular lumen. However, on the other hand, too much flexibility and elasticity of the flexible driving shaft 120 connected to one end of the functional element 130 may be detrimental to stable rotation transmission of the flexible driving shaft 120 and the functional element 130, and even may induce vibration and standing waves. Therefore, it is advantageous to perform a region hardening correction to some extent on the end of the flexible drive shaft 120 to which the functional element 130 is attached, which is advantageous to suppress or reduce the generation of vibration and standing waves.

Specifically, to suppress the generation of vibrations and standing waves of the flexible drive shaft 120, in one embodiment, as shown in fig. 3-5, the elastic spiral wound spring tube segment 121 includes a first wound spring segment 1211 and a second wound spring segment 1212, wherein the rigid metal tube segment 122 is connected to the drive motor 310 and the second wound spring segment 1212 is connected to the functional element 130. And, the rigid metal tube section 122, the first coiled spring section 1211 and the second coiled spring section 1212 are coaxially disposed and connected in sequence in the axial direction, the bending stiffness of the second coiled spring section 1212 being less than the bending stiffness of the first coiled spring section 1211. As such, the bending stiffness of the flexible driving shaft 120 is gradually reduced along the direction from the driving handle 300 to the functional element 130, and it is understood that the bending stiffness of the flexible driving shaft 120 is gradually reduced, which is advantageous to avoid the flexible driving shaft 120 from bending suddenly and thus to suppress the vibration and standing wave of the flexible driving shaft 120. Meanwhile, in the process that the flexible driving shaft 120 stretches into the body from outside, the end of the flexible driving shaft 120 with smaller rigidity firstly enters the body, so that the pushing performance of the thrombus removal system can be further enhanced, and the clinical use requirement can be better met.

More specifically, in order to achieve the difference in bending rigidity of the first coiled spring segment 1211 and the second coiled spring segment 1212, the following schemes may be adopted:

scheme one: the first coiled spring segment 1211 and the second coiled spring segment 1212 are each formed of a coiled metal wire, the cross-sectional area of the coiled metal wire of the first coiled spring segment 1211 being greater than the cross-sectional area of the coiled metal wire of the second coiled spring segment 1212, such that the bending stiffness of the first coiled spring segment 1211 is greater than the bending stiffness of the second coiled spring segment 1212.

In a second embodiment, the flexible drive shaft 120 is provided with a first spring segment 1211 having a large pitch and a wide spiral at the end near the drive handle 300, and the flexible drive shaft 120 is provided with a second spring segment 1212 having a small pitch and a narrow spiral at the end remote from the drive handle 300. Such a segmented design allows the flexible drive shaft 120 to meet both anti-rattle performance and vascular turn requirements through more complex spatial configurations.

In the third aspect, the materials of the spiral metal wires of the first coiled spring segment 1211 and the second coiled spring segment 1212 are different, and the poisson ratio characteristics of the metal materials such as nickel-titanium alloy, SUS304 stainless steel, cobalt-nickel alloy, platinum-iridium alloy and the like are utilized to be different, so that the bending rigidity of the elastic spiral coiled spring segment 121 is distributed in sections. In the aspect of the material of the elastic spiral winding spring tube section 121 of the flexible driving shaft 120, different metal materials are combined, the sectional welding design is adopted, the whole design can be adjusted as required, the cost is lower, and the mechanical property is more excellent.

It should be noted that in another embodiment, as shown in fig. 6, the elastic spiral wound spring tube segment 121 further includes a third wound spring segment 1213, the third wound spring segment 1213 is connected to an end of the second wound spring segment 1212 remote from the first wound spring segment 1211, and the bending stiffness of the third wound spring segment 1213 is greater than the bending stiffness of the second wound spring segment 1212.

In one embodiment, the flexible drive shaft 120 is formed from a central wire, the outer face of which is wound alternately from layers of wire, the wire being circular in cross-section.

In one embodiment, as shown in fig. 7 and 8, the elastic spiral wound spring tube segment 121 is formed of a spiral wire, and the section of the spiral wire of the elastic spiral wound spring tube segment 121 is rectangular or rectangular-like (including but not limited to a parallelogram and trapezoid, but other irregular quadrilaterals are also possible). It will be appreciated that a rectangular cross-section has a smaller circumferential stiffness and a greater axial stiffness than a circular cross-section. The rectangular cross section has a smaller circumferential stiffness than the circular cross section, meaning that when the rectangular cross section elastic spiral wound spring tube segment 121 is subjected to forces perpendicular to the axial direction, the rectangular cross section elastic spiral wound spring tube segment 121 is more prone to bending, and thus the rectangular cross section elastic spiral wound spring tube segment 121 is more prone to travel in the direction of bending of the fitting blood vessel. The rectangular section has greater axial rigidity relative to the circular section, which means that when the elastic spiral wound spring tube section 121 of the rectangular section is subjected to the action of the force parallel to the axial direction, the elastic spiral wound spring tube section 121 of the rectangular section is more difficult to bend, so that the mechanical feedback of the elastic spiral wound spring tube section 121 of the rectangular section is shorter in the pushing process, and the elastic spiral wound spring tube section 121 can accurately enter the preset position in the blood vessel (the blood vessel has a plurality of branches, and the mechanical feedback is too long and is not easy to control), thereby greatly improving the pushing performance of the flexible driving shaft 120.

Thus, in summary, the axial and circumferential anisotropy of the rectangular section of the elastic helically wound spring tube segment 121 is more pronounced than that of a circular section, which is required to push the flexible drive shaft 120 and its distal rotating basket 131 through the body vessel to a preset position within the vessel.

Further, in an embodiment, as shown in fig. 7 and 8, the present application optimizes the geometric parameters (such as pitch, thickness, width, and gap of the spiral line) of the elastic spiral spring tube segment 121, so as to provide the elastic spiral spring tube segment 121 with a strong torsion rigidity characteristic, and consider the tortuosity and the complex distribution of the human blood vessels, and the geometric parameters of the elastic spiral spring tube segment 121 are designed and limited by the requirements of flexibility and pushing performance.

Specifically, a cross-sectional width of the spiral wire of the elastic spiral spring tube section 121 is defined as a, a cross-sectional thickness of the spiral wire of the elastic spiral spring tube section 121 is defined as b, a pitch of the elastic spiral spring tube section 121 is defined as c, a pitch of the elastic spiral spring tube section 121 is defined as e, and a gap of the elastic spiral spring tube section 121 is defined as h, wherein e=a+h. The section of the elastic spiral wound spring tube segment 121 perpendicular to the central axis is a circular ring. The elastic spiral wound spring tube segment 121 is approximately modeled as a torsion spring and the torsion section modulus of the elastic spiral wound spring tube segment 121 is calculated in a method of calculating the torsion section modulus of the torsion spring.

Calculation of the torsional section coefficient of the elastic spiral wound spring tube segment 121:

(1) The spiral equation is:

①；

②；

(3) the method comprises the steps of carrying out a first treatment on the surface of the t is a helix angle parameter, and the unit is radian;

when the spiral section rotates one revolution, the actual section parameter④；

Condition 1: carrying t1 obtained by calculation of the formula (4) into the formulas (1) and (2) to obtain X (t 1) and Y (t 1);

condition 2: initial value X (t 0) =c, Y (t 0) =0;

combining condition 1 and condition 2, can be countedCalculating the section angle of the elastic spiral wound spring tube section 121。

(2) The torsion-resistant section coefficient of the section of the elastic spiral wound spring segment 121 perpendicular to the central axis is:

⑤；

polar moment of inertia of the section 121 of the elastic spiral wound spring tube⑥；

Torsion angle of elastic spiral wound spring tube section 121(7) The method comprises the steps of carrying out a first treatment on the surface of the Where l is the axial length of the elastic spiral wound spring tube segment 121, G is the shear modulus of the material of the elastic spiral wound spring tube segment 121, and T is the output torque of the elastic spiral wound spring tube segment 121;

torsion angle per unit length, i.e.(8) The method comprises the steps of carrying out a first treatment on the surface of the The value of the torsion angle can be set according to the requirement of the angular velocity of the flexible driving shaft 120 near the end of the functional element 130 in the specific application;

to ensure that the entire flexible drive shaft 120 is not unstable, it is desirable that the helical wire gap h1 after the flexible drive shaft 120 is torsionally wound satisfy condition 0<h1 is less than or equal to h; when l satisfies the condition l=e, then it is possible to obtain ⑨；

LimitingSo that the flexible drive shaft 120 can maintain an equilibrium state under expected working conditions and has a certain energy storage capacity for storing and releasing angular energy; the energy storage capacity is marked by->The larger the control angle θ, the more turns the greater the energy storage capacity of the entire spring spiral spring segment 121. The ability to reject dynamic load output torque fluctuations (uneven interactions/blockage of different substances such as thrombus, plaque, vessel wall and the like within the vessel lumen with the functional element 130, resulting in fluctuation of the distal rotational speed/output torque of the flexible drive shaft 120) is greatly limited by the excessively weak energy storage capability, and if the energy storage capability is not well matched with the hardware safety system, a great potential safety hazard may be caused.

c is the declarative dimension confirmation (generally dependent on the diameter of the vessel lumen), and b is the pushability and compliance capability determination.

All equations are brought in by r, yielding the following equation:

；

solving the above equation to obtain

；

The spiral section length a is solved by the above formula.

Given the intensity of the desired absorbed energy of the elastic spiral wound spring tube segment 121 in the drive system, series of tests are designed in groups to obtain optimized values of the parameter a and the pitch e, and according to the optimized parameters a and the optimized values of the pitch e, the single stainless steel tubule is spirally cut to form the elastic spiral wound spring tube segment 121 and the rigid metal tube segment 122.

In addition, it is considered that the entire elastic spiral wound spring tube segment 121 is used for advancing/retreating in a tortuous vessel lumen of a human body, which requires good flexibility and pushing performance of the elastic spiral wound spring tube segment 121. Moreover, the lumen of the elastic spiral wound spring tube segment 121 is designed to accommodate or pass through other tube components, and the outer surface of the elastic spiral wound spring tube segment 121 is designed to travel/retract within a small and narrow vessel lumen or other diameter-defined outer tube component, which has defined requirements for both the inner and outer diameters of the elastic spiral wound spring tube segment 121; thus, geometric parameters a and e (e=a+h) are selected to provide a variable torsional stiffness design of the elastic helical coiled spring segment 121 to achieve a desired value of torsion angle matching the drive motor 310 to increase the response time Tb of the flexible drive shaft 120 when coiling occurs.

The driving motor 310 drives the functional element 130 to rotate through the flexible driving shaft 120 in an initial stage: the end of the flexible drive shaft 120 adjacent to the drive motor 310 rotates as the drive motor 310 rotates. At this time, the functional element 130 to which the flexible drive shaft 120 is connected is blocked by a lumen of a blood vessel such as thrombus, and the end of the flexible drive shaft 120 to which the functional element 130 is connected and the functional element 130 have relatively stationary inertia. Thus, both ends of the flexible drive shaft 120 are twisted, the spiral wire is wound, and the gap of the elastic spiral wound spring tube section 121 is axially contracted until the flexible drive shaft 120 is in the equilibrium state B.

In equilibrium state B, the drive motor 310 is dynamically loaded (the functional element 130 rotates under different retarding forces), and the output torque of the flexible drive shaft 120 at the end connected to the functional element 130 changes as the dynamic load fluctuates, which changes the actual output torque of the flexible drive shaft 120 at the end connected to the functional element 130, which advances along the oscillation center output torque (fitting curve). In the dynamic load state, the flexible driving shaft 120 designed by the variable torsion rigidity characteristic has good energy storage capacity for storing and releasing angular energy, and can enable the driving motor 310 to be in an intermittent working state of energy storage and release, so that the effect of inhibiting fluctuation of dynamic load output torque is achieved. For example, under in-vivo conditions, when the retarding force applied to the functional element 130 increases, the rotational speed decreases, and at this time, the rotational speed of the driving motor 310 remains unchanged, the flexible driving shaft 120 will exhibit opposite directions at both ends and twist slightly to store energy, and the output torque of the end of the flexible driving shaft 120 connected to the functional element 130 is greater than the output torque of the end of the flexible driving shaft 120 near the driving handle 300, and the flexible driving shaft 120 starts to release the stored energy, which is equivalent to additionally increasing the output torque, so as to attempt to break the obstruction (for example, increasing the bolt breaking force and increasing the output torque of crashing and plaque breaking). In an initial stage, the variable torsional stiffness characteristic of flexible drive shaft 120 allows for a time delay in the distal end of flexible drive shaft 120 in response to proximal rotation of flexible drive shaft 120, avoiding abrupt high-speed rotation of functional element 130 to stimulate the blood vessel, and slowing down the spasmodic response of the blood vessel.

The flexible drive shaft 120 of the present invention has an outer diameter within the range of 1mm-8mm and a wall thickness within the range of 0.1mm-1.5 mm.

In one embodiment, the rectangular cross-sectional area of the coiled wire (length x width) of the elastic coiled spring tube segment 121 is between 0.5 x 0.1 and 6.5 x 1.2 (in mm).

In one embodiment, the rectangular cross-sectional area of the first coiled spring 1211 spiral wire has a value (length x width) between 0.5 x 0.1 and 5.5 x 1.2 (each in mm); the rectangular cross-sectional area of the coiled wire of the second coiled spring segment 1212 has a value (length x width) of between 0.5 x 0.1 and 3.5 x 1.2 (in mm).

In one embodiment, the outer diameter of the spring coiled spring tube section 121 is 0.8mm to 3.3mm, and the gap between the two threads is 0.05mm to 0.6mm.

In an embodiment, the length of the first coiled spring 1211 ranges from 5mm to 200mm, which has the effect of suppressing vibration and standing waves of the flexible drive shaft 120 portion between the driving handle 300 and the surgical access port (e.g., the driving handle 300—the luer of the aspiration tube assembly 200), wherein the suppression effect of the first coiled spring 1211 is particularly remarkable in the length range from 10mm to 100 mm.

In order to inhibit the vibration and standing wave of the flexible driving shaft 120, the length of the rigid metal tube section 122 fixedly connected with the elastic spiral winding spring tube section 121 ranges from 20mm to 350mm, so that the vibration and standing wave of the flexible driving shaft 120 can be effectively inhibited under working conditions. The length of the rigid metal tubing segment 122 ranges from 50mm to 260mm, and vibration and standing waves are particularly pronounced in the portion of the flexible drive shaft 120 between the drive handle 300 and the surgical access port (e.g., drive handle 300-suction tube assembly 200 luer).

Further, the present application provides an invasive device (including but not limited to a thrombus removal system) that prevents damage to body tissue such as blood vessels by the invasive device in order to improve the safety of operation of the invasive device.

In an embodiment, as shown in fig. 9, the invasive apparatus further includes a power source 320 and an over-current protection module 330, the rotational resistance received by the functional element 130 and the driving current of the driving motor 310 are in positive correlation and are in a one-to-one correspondence, the power source 320 is electrically connected to the driving motor 310 through the over-current protection module 330, when the rotational resistance received by the functional element 130 is greater than a second preset resistance value, the driving current of the driving motor 310 is greater than a preset current value, and the over-current protection module 330 is capable of breaking so that the driving motor 310 stops outputting the torque, wherein the second preset resistance value is greater than the first preset resistance value.

In practice, as shown in fig. 41, it should be noted that, in fig. 41, there are three graphs, where a graph x is a graph of a function of an output torque T and a time T at one end of a conventional driving shaft connecting functional element, a graph y is a graph of a function of an output torque T and a time T at one end of a flexible driving shaft 120 connecting functional element 130 (including but not limited to a rotating basket 131) according to the present application, and a graph z is a graph of a function of an output torque T and a time T at an oscillation center of the flexible driving shaft 120 according to the present application. The difference between fig. 41 and fig. 40 is that in fig. 41, the overcurrent protection module 330 is introduced into the flexible driving shaft 120 according to the present application, and before the output torque of the end of the flexible driving shaft 120 near the functional element 130 reaches the peak torque, the overcurrent protection module 330 is disconnected, so that the driving motor 310 stops rotating, and at this time, the output torque of the flexible driving shaft 120 drops to zero rapidly.

In this way, when the end of the flexible driving shaft 120 connected to the functional element 130 is suddenly jammed/stopped, first, the response time Tb for the output torque of the flexible driving shaft 120 near the end of the functional element 130 to peak will be greatly increased, so that the monitoring control part of the driving handle 300 has enough risk to cope with the response time, and the risk of an in vivo safety accident is reduced. Further, by providing the overcurrent protection module 330, the driving motor 310 is de-energized and stopped, and the driving motor 310 no longer outputs torque, at this time, the output torque of the end of the flexible driving shaft 120 near the functional element 130 will also decrease to zero rapidly, and the end of the flexible driving shaft 120 near the functional element 130 will reverse torsion until the normal configuration is restored. In this way, the pressure of the output torque of the flexible driving shaft 120, which is close to one end of the functional element 130, on the blood vessel is rapidly relieved, so that the damage to the human body tissues such as the blood vessel caused by the fact that the driving motor 310 continuously outputs a larger peak torque is effectively avoided, and the operation safety of the invasive instrument is further improved.

Further, because the volume of the inner cavity of the blood vessel is smaller, the difficulty of directly arranging the dynamic torque sensor 410 in the blood vessel to detect the rotation resistance received by the functional element 130 is larger, and the corresponding relation between the rotation resistance received by the functional element 130 and the driving current of the driving motor 310 is obtained through experiments, and the rotation resistance received by the functional element 130 is indirectly judged by using the driving current of the driving motor 310, so that the dynamic torque sensor 410 does not need to be arranged in the blood vessel, and the design difficulty of invasive instruments is greatly reduced. In addition, the application realizes the stop of the driving motor 310 through the disconnection of the overcurrent protection module 330 without setting a complex control system, thereby further reducing the design difficulty of invasive instruments.

In view of the need for real-time dynamic monitoring and control of invasive instruments, the invasive instrument of the present application employs a self-healing circuit design to achieve the objective of continuously monitoring and controlling the power output of the drive motor 310.

Specifically, in one embodiment, as shown in fig. 9, the over-current protection module 330 includes an over-current protection element 331 and a P-channel MOS transistor 332, the power supply 320 is serially connected to the over-current protection element 331 and the driving motor 310 in sequence to form a first branch, and the power supply 320 is serially connected to the P-channel MOS transistor 332 to form a second branch. When the current of the first branch is less than or equal to the preset current value, the over-current protection element 331 can maintain the on state, the P-channel MOS transistor 332 is connected to the high level, and the driving motor 310 can operate normally. When the current of the first branch is greater than the preset current value, the over-current protection element 331 is in an off state, the P-channel MOS transistor 332 is connected to a low level, and the driving motor 310 stops operating.

The P-channel MOS transistor 332 is used to control the on/off of the operating circuit according to the on/off of the over-current electronic protection element 331, and F1 is used as the over-current electronic protection element 331 and is used for current monitoring and on/off. When the overcurrent electronic protection element 331 is turned off, the low level is connected to the G stage of the P-channel MOS transistor 332, resulting in conduction of current from the source (S stage) to the drain (D stage). The diode is used for preventing reverse connection protection, the resistor R8 is a load resistor, and excessive current is prevented from breaking down other circuit components. VCC is the working circuit interface. The positive electrode of the power supply 320 is at 2, and the negative electrode of the power supply 320 is at 1.

Further, in an embodiment, as shown in fig. 9, the overcurrent protection module 330 further includes an alarm element 333, the alarm element 333 is connected in series to the second branch, and when the P-channel MOS transistor 332 is at the low level, the second branch is turned on, and the alarm element 333 can issue an alarm.

Thus, the circuit operation principle of the overcurrent protection module 330 is as follows: when the over-current electronic protection element 331F1 is turned on, the operating voltage VCC is normal, the G-stage of the P-channel MOS transistor 332 is connected to the high level, S-D is not turned on, and the alarm element 333 is not operated. When the overcurrent electronic protection element 331F1 is turned off, the operating voltage VCC is turned off, the G-stage of the P-channel MOS transistor 332 is turned on and S-D is turned off. The alarm element 333 starts to issue an alarm.

Note that, the alarm element 333 may be a horn, a buzzer, a tube alarm, or the like, which are not illustrated herein.

The overcurrent protection is that the overcurrent protection module 330 operates when the current exceeds a preset current value. The key parameter of the overcurrent protection module 330 is determined by its model, and is mainly the parameter Itrip, which is called current interruption.

When the current flowing through the protected element exceeds a preset current value, the overcurrent protection module 330 operates, and ensures the selectivity of the operation by using the timing, so that the circuit breaker trips and sends out an alarm signal. The self-restoring fuse is one kind of the overcurrent electronic protection element 331, and is composed of a specially treated polymer resin and conductive particles distributed therein. When the circuit is short-circuited or overloaded, the high current flowing through the self-recovery fuse causes the polymeric resin to melt, the volume of the polymeric resin to rapidly increase, a high-resistance state is formed, and the working current is rapidly reduced, so that the circuit is limited and protected. After the fault is removed, the polymer resin is cooled again to crystallize, the volume is contracted, the conductive particles form a conductive path again, and the self-recovery fuse is restored to a low-resistance state, so that the circuit is conducted, and the self-recovery fuse does not need to be replaced manually.

The over-current electronic protection element 331 is screened in the following manner, the environmental conditions in the blood vessel lumen are simulated, and various unexpected working conditions (such as excessive plaque hardness, high thrombus concentration toughness, clamping and hanging of the functional element 130 and the like) are set; the test records the minimum torque (the torque received by the functional element 130 or the torque received by the flexible driving shaft 120) in various unexpected working conditions and the corresponding working current (the driving current of the driving motor 310), so as to obtain a torque-current data relation chart in various unexpected working conditions. And screening the commercial self-recovery fuses meeting the control circuit conditions according to the torque-current data relation chart. The self-healing fuse design is connected in series with the overcurrent protection module 330, and the control of the torque output of the driving motor 310 is achieved by opening/closing the circuit of the driving motor 310 by the characteristics of the self-healing fuse. For example, when the driving current gradually increases, the temperature of the over-current protection element 331 increases, and when the driving current increases to a certain threshold value to raise the temperature of the over-current protection element 331 to a preset temperature, a great resistance is generated, so that the series circuit is disconnected, and the power supply to the driving motor 310 is stopped, so that the function of protecting the entire driving handle 300 circuit is achieved. After the abnormal current is restored to the normal value, the temperature of the over-current electronic protection element 331 is restored to the normal temperature, the resistance value is restored to the normal value, and the over-current protection module 330 resumes the operation of the channel again, so that the purpose of continuous monitoring is achieved.

In the prior art, it is conventional practice to use the current of the drive motor 310 itself versus the torque characteristic of the flexible drive shaft 120 (or the functional element 130) to set the torque threshold to be controlled. However, since the current-torque characteristic curve relationship of the drive motor 310 itself is different from the current-torque characteristic curve relationship of the drive motor 310 after loading the flexible drive shaft 120, the current-torque characteristic curve relationship of the drive motor 310 itself cannot be used directly for setting the current threshold value or the torque threshold value. Therefore, the current versus torque characteristic curve data graph of the drive motor 310 after loading the flexible drive shaft 120 needs to be retrieved, and the current threshold or the torque threshold needs to be re-matched.

As shown in fig. 10 to 12, the test and experiment device is composed of a multimeter 420, a power supply device 430, a driving motor 310, a first connector 440, a dynamic torque sensor 410, a second connector 450, and a flexible driving shaft 120 carrying a functional element 130.

The new torque-current relationship is obtained as follows:

after the driving motor 310, the dynamic torque sensor 410 and the flexible driving shaft 120 with the functional element 130 are sequentially connected through the first connector 440 and the second connector 450 to form a test assembly, the flexible driving shaft 120 with the functional element 130 is placed in the simulated vascular cavity;

Setting various unexpected working conditions (such as excessive plaque hardness, high thrombus consistency and toughness, clamping and hanging of the functional element 130 and the like); under unexpected working conditions, the torsion conditions of the flexible driving shaft 120 and the functional element 130 in the test are observed, and new torque-current relation curve data obtained in the test are recorded; from the new torque-current curve data, a threshold value of the required monitored current is determined.

Further, the setting steps of the in-vitro unexpected working condition are as follows:

(1) the method is mainly characterized in that the inner side (the surface is cut off, and the hard blocks are adhered after being placed) of an ultrathin silica gel tube is adhered with hard blocks (the sizes of the hard blocks are different according to different treatment positions by referring to doctors), and the situation of sudden blood vessel hard blocks encountered clinically is simulated.

(2) Ligating a certain section of the ultrathin silicone tube to simulate the condition of vascular stenosis.

Observation of torsion conditions: the ultra-thin silicone tube (transparent) was directly visualized. Judging the safety condition:

(1) the overall torque of the functional element 130 exceeds its predetermined set point (this value is mainly determined by its connection strength x a safety factor);

(2) the overall morphology of the functional element 130 is that within unintended control;

(3) the flexible drive shaft 120 is in an abnormal twisted state;

(4) The flexible drive shaft 120 is severely dithered by a factor of 2 and more over the normal operating dithering force.

Animal test verification: the whole invasive instrument is placed in a pig body, the maximum rotating speed is used for movement, after normal test, the whole invasive instrument can be safely processed, cut into slices after 10% formalin is fixed, hematoxylin-eosin staining and paraffin embedding are carried out, and the situation of vein damage of a test section is observed under a microscope.

In one embodiment, the flexible drive shaft 120 is cut from a single thin tube of stainless steel, wherein the flexible drive shaft 120 has an outer diameter of 2.5mm, a wall thickness of 1mm, and an overall length of 150cm; wherein the rigid metal tube section 122 has a length of 150mm; the optimum values for the helical geometry a (helical line width) and the pitch e of the elastic helical spring tube section 121 are a=0.8 and e=0.9. The torque threshold f=0.005 n×m at the distal end of the flexible drive shaft 120 in the drive system. The current threshold i=0.2a in the control circuit. The response time tb=4s for winding the elastic spiral wound spring tube segment 121.

In practice, it has been found that there is a possibility of tearing and breaking of the flexible drive shaft 120 rotating at high speed in critical applications; thus, it is necessary that the drive shaft be used in conjunction with a self-lubricating sheath 150.

Specifically, in one embodiment, as shown in FIG. 4, the flexible drive shaft 120 is an elongated hollow thin-walled metal tube shaft that is encased in a self-lubricating sheath 150. Wrapping the outer surface of the flexible drive shaft 120 with the self-lubricating sheath 150 facilitates sliding and rotation of the flexible drive shaft 120 within the lumen of the mating aspiration tube assembly 200.

Specifically, the self-lubricating sheath 150 is made of polymer material, such as polytetrafluoroethylene, pebax, nylon, polyimide, FEP, polyethylene or PTFE, so that the self-lubricating sheath 150 coated on the outer surface of the flexible driving shaft 120 has a certain lubrication effect, so as to improve the transmission efficiency. The self-lubricating sheath 150 has a wall thickness of 0.01mm to 0.1 mm.

However, the applicant has found in practice that under operating conditions, the second coiled spring section 1212 and the self-lubricating sheath 150 are at risk of relative sliding in the circumferential direction, such that the second coiled spring section 1212 and the self-lubricating sheath 150 cannot rotate synchronously under operating conditions. In order to solve the above technical problem, in one embodiment, it is known through a lot of experiments that widening the spiral width of the spiral metal wire of the second coiled spring section 1212, or increasing the roughness of the outer surface of the spiral metal wire of the second coiled spring section 1212, or filling the adhesive between the flexible driving shaft 120 and the self-lubricating sheath 150, will generate an effect similar to the head end anchoring effect, and can effectively increase the friction force between the second coiled spring section 1212 and the self-lubricating sheath 150, thereby avoiding the situation that the self-lubricating sheath 150 and the flexible driving shaft 120 relatively slip due to the transmission of the integral moment.

In the aspect of improving thrombolysis efficiency, the thrombolysis is mainly realized by two aspects: 1. chopping the thrombus into small pieces by a cutting wire 1313 rotating at a high speed by the rotating basket 131 itself; 2. in the case of auxiliary thrombolytic drugs, a high-speed vortex effect caused by stirring of the rotary basket 131 accelerates the fusion process of thrombolytic drugs and thrombus, promotes the reaction of thrombolytic drugs and thrombus, accelerates the reaction process of thrombolytic drugs, and thus rapidly cuts off and breaks large thrombus from the weak connection part into small-particle thrombus. Compared with the original complete large-lump thrombus, the broken thrombus mass has the multiplied specific surface area, so that the infiltration area of the thrombus mass is increased, the distribution and the adhesion of thrombolytic agents are facilitated, the small-lump thrombus can be further decomposed and cracked, the thrombolysis time is shortened, the thrombolysis efficiency is improved, the risk of blockage of the suction tube assembly 200 is reduced, and the operation is smoothly carried out.

In the present application, as shown in fig. 13-15, the rotary basket 131 of one of the thrombus removal system assemblies includes a first rotor member 1311, a second rotor member 1312, and a plurality of strands of cutting wires 1313 extending helically around the central axis of the rotary tube assembly 100, the strands of cutting wires 1313 being distributed along the circumference of the rotary tube assembly 100 and constituting an olive-shaped cage 1314, and the cage 1314 being connected at one end to the flexible drive shaft 120 by the first rotor member 1311 and at the other end to the second rotor member 1312. The cage 1314 is olive-shaped (large middle and small ends) in an unloaded or unrestricted state. The material of the cutting wire 1313 constituting the rotary basket 131 is a metal material such as nickel-titanium alloy, SUS304 stainless steel, cobalt-nickel alloy, or platinum-iridium alloy. The number of cutting wires 1313 is 3-6.

The rotating basket 131 is designed for in-lumen rotational cutting of thrombus attached to the vessel wall, shear force breaking of thrombus, and agitation dispersion of thrombolytic agents. The design and use determine that the structure of the rotary basket 131 needs to have a certain degree of structural rigidity, morphological stability and flexible deformability under the working condition. For example, prior to intraluminal infusion of a thrombolytic agent, the cutting wire 1313 of the rotating basket 131 is required to traverse the thrombus slotting slit in order for the thrombolytic agent to penetrate axially along the vessel segment. After injection of thrombolytic agents into the lumen of a blood vessel, the rotary basket 131 is driven to rotate at a high speed by the driving motor 310, and the thrombus is broken or lysed by a shearing force generated by the cutting wire 1313 moving at a high speed, so that the dissolution of the thrombus into a small-particle-diameter mixed fluid is accelerated. The rotating basket 131 and the flexible driving shaft 120 rotate to make the mixture in the lumen form high-speed vortex, so that thrombolytic and thrombus reaction are promoted, the reaction progress of the thrombolytic is accelerated, and therefore, the rotating basket 131 needs to maintain the stirring function in the radial direction. The rotary cutting is used for removing thrombus attached to the vessel wall, the vessel wall is required to be supported by the circumferential expansion of the rotary basket 131, the vessel wall is not damaged, the rigidity of the rotary basket 131 is overlarge, the vessel wall is easy to damage when the rotary basket rotates at a high speed, the rigidity of the rotary basket 131 is overlarge, and the thrombus breaking capability of the rotary basket 131 is greatly weakened. The rotary basket 131 needs to be flexible before reaching the vessel segment in order to travel around tortuous vessel environments, etc. Therefore, the geometry design of the rotating basket 131 is particularly important. The stiffness of the rotating basket 131 is primarily achieved by adjusting the wire diameter of the cutting wire 1313 and by winding the cutting wire 1313 in a single strand.

In one embodiment, as shown in fig. 15, each cutting wire 1313 is rotated 180 ° about the central axis of the rotating tube assembly 100 in the direction from the drive handle 300 to the balloon assembly 140, i.e., each cutting wire 1313 is semi-helical. The half-helical cutting wires 1313 are circumferentially spaced around the central axis of the rotary tube assembly 100, and both ends of the half-helical cutting wires 1313 are fixedly connected to the first rotor member 1311 and the second rotor member 1312, respectively, to form an olive-like cage 1314.

In this manner, the contractibility of the rotary basket 131 is greatly improved, and in particular, when the rotation angle of the cutting wire 1313 about the central axis of the rotary tube assembly 100 is 180 degrees, the distance between the front and rear ends of the cutting wire 1313 is the farthest, and the distance between the two inflection points on the cutting wire 1313 is the farthest, so that the moment arm of the lever reaches the longest in terms of the lever principle, which is advantageous in that the maximum resistance torque is generated when the cutting wire 1313 is subjected to the rotation resistance, that is, in that the shrinkage torsion occurs after the cutting wire 1313 is extruded. When the rotation angle of the cutting wire 1313 around the central axis of the rotary pipe assembly 100 is less than 180 degrees, the spiral angle of the cutting wire 1313 is too small, and the overall shape is biased to be straight, so that the cutting wire 1313 is difficult to contract in the spiral direction after receiving rotation resistance, but is directly destructively deformed in the direction perpendicular to the axis. And when the rotation angle of the cutting wire 1313 around the central axis of the rotary tube assembly 100 is greater than 180 degrees, the distance between the two inflection points of the cutting wire 1313 becomes small, and the resistance torque is reduced when the cutting wire 1313 receives the rotation resistance, that is, the shrinkage performance of the cutting wire 1313 and even the cage 1314 is reduced.

Further, in one embodiment, as shown in fig. 13, the rotating basket 131 further includes a stop member 1315, the stop member 1315 passing through the cage 1314 along the central axis of the rotating tube assembly 100. In this manner, excessive shrinkage of the cage 1314 is prevented from causing plastic deformation of the cutting wire 1313.

And, in practice, it has been found that under load rotational speed conditions (operating conditions), as the rotational speed increases, the dynamic diameter of the rotating basket 131 increases slowly compared to the static diameter. Accordingly, by providing the stop member 1315 with the stop member 1315 connected to the first rotor member 1311 and extending toward the second rotor member 1312, the stop member 1315 and the second rotor member 1312 are spaced apart to prevent excessive movement of the second rotor member 1312 toward the first rotor member 1311. In this way, it is possible to prevent excessive expansion of the rotating basket 131 in the axial direction and reduce the risk of damaging the blood vessel.

The stop member 1315 has an axial length value that is 0.3-0.8 times the axial length value of the rotating basket 131.

Under operating conditions, if the direction of rotation of the flexible drive shaft 120 is opposite to the direction of helical extension of the cutting wire 1313 about the central axis of the rotary tube assembly 100 (e.g., the drive shaft rotates counter-clockwise with the left-handed rotary basket 131), when the rotary basket 131 is accidentally blocked (e.g., when plaque is encountered during thrombus removal), the second rotor member 1312 ceases to rotate, the rotary basket 131 will move in a direction that reduces its radial profile, while the second rotor member 1312 moves in a direction toward the first rotor member 1311, such that the radius of the rotary basket 131 is adaptively reduced to avoid collisions of harder unintended materials, preventing the semi-helical cutting wire 1313 from hinging to the harder material and breaking.

In one embodiment, the rotational direction of the output of the drive handle 300, the rotational direction of the flexible drive shaft 120 (primarily taking into account the direction of stored energy, i.e., contracted stored energy or expanded stored energy), and the rotational direction of the rotating basket 131 need to be adaptively matched. The common collocation is left-handed-right-handed or right-handed-left-handed collocation. For safety reasons, the rotational direction of the flexible drive shaft 120 should be such that its constrictive energy storage properties are utilized as much as possible to prevent its form from moving in an increasing direction. And the cooperation of rotatory basket 131 and flexible drive shaft 120, a safety function that can realize is, when rotatory basket 131 meets and hinders the inefficacy, the free end of rotatory basket 131 (the one end that keeps away from flexible drive shaft 120) is fixed, will make rotatory basket 131 wholely shrink, the trend of shrink can prevent unexpected emergence, simultaneously, shrink the form and increased the rigidity of rotatory basket 131, the energy release of cooperation energy storage drive shaft system, can be in the maximum obstacle that breaks of safety margin, for not energy storage system, the maximum power of rotatory basket 131 can be promoted instantaneously.

It should be noted that the first rotor member 1311 of the rotary basket 131 is fixedly connected to the resilient spiral wound spring tube segment 121, and the second rotor member 1312 of the rotary basket 131 is axially clearance fitted with the inner tube 110 such that the second rotor member 1312 is capable of an axially unrestricted sliding movement on the outer surface of the inner tube 110. Also, balloon assembly 140 is configured to have an outer diameter dimension that resists second rotor member 1312 from exiting inner tube 110.

In the present application, as shown in fig. 14, the geometric parameters of the rotary basket 131 are as follows: in the unloaded state, the maximum radial distance v of the semi-helical cutting wire 1313 to the central axis is satisfied, with v being 2.5mm < 7mm. The semi-spiral cutting wire 1313 is a nickel-titanium wire, a 304 stainless steel wire, a cobalt-nickel alloy wire or a platinum-iridium alloy wire with better heat setting capability. The cross section of the semi-spiral cutting wire 1313 is circular, and in the application scene of removing thrombus, the cross section diameter u of the cutting wire 1313 is more than or equal to 0.1mm and less than or equal to 1.5mm by adopting a single-strand wire shape. The length L of the rotary basket 131 along the central axis direction of the rotary pipe assembly 100 is 20 mm.ltoreq.L.ltoreq.60 mm. The shoulder width value q of the rotary basket 131 (the shape of the linear cutting wires 1313 extending along the axial direction at the two ends of the cage 1314) is more than or equal to 2mm and less than or equal to 10mm, and the proper shoulder width value range of the rotary basket 131 can effectively maintain the dynamic maximum diameter of the rotary basket 131 at the rated rotation speed, and the overall shape and the structural rigidity of the rotary basket 131 are maintained. The maximum radius of the semi-helical cutting wire 1313 to the central axis ranges from 3mm to 9mm under a load of 500RPM to 1500 RPM.

In one embodiment, as shown in fig. 16-21, the driving handle 300 includes a housing 340, a driving motor 310 and a circuit controller 350, wherein the driving motor 310 and the circuit controller 350 are both disposed in the housing 340, and the circuit controller 350 can control the driving motor 310 to be turned on and off. The one end that flexible drive shaft 120 is close to actuating handle 300 is equipped with the triangle connector 360, and casing 340 corresponds triangle connector 360 and is equipped with triangular groove 341, and flexible drive shaft 120 can insert in triangular groove 341 and with driving motor 310 joint cooperation through triangle connector 360 to make driving motor 310 can drive triangle connector 360 and drive flexible drive shaft 120 rotation. The flexible driving shaft 120 is movably sleeved with a fastening ring 370, the casing 340 is provided with a fastening part 342 corresponding to the fastening ring 370, and the fastening ring 370 is stopped at one end of the triangle connector 360, which is close to the rotary basket 131, and can be in clamping fit with the fastening part 342, so that the flexible driving shaft 120 is clamped with the driving handle 300.

The driving handle 300 further comprises a gear set 380, wherein the gear set 380 is connected to an output end of the driving motor 310 and is used for controlling the output rotating speed of the driving motor 310.

It should be noted that the circuit controller 350 is configured to connect the overcurrent protection modules 330 in series to form a self-recovering controller.

Thus, the connection convenience of the flexible driving shaft 120 and the driving handle 300 is greatly improved, and the flexible driving shaft 120 and the driving handle 300 can be disassembled and assembled at any time.

Further, in an embodiment, as shown in fig. 16-21, the driving handle 300 further includes a speed adjusting knob 390, and the speed adjusting knob 390 is electrically connected to the circuit controller 350, so that the output rotation speed of the driving motor 310 is controlled by the circuit controller 350, so that the rotating basket 131 can achieve stepless speed adjustment. The clasp 342 is disposed over the governor knob 390.

It should be noted that the inner tube 110 is fixedly connected to the driving handle 300 through the locking head 111, and the inner tube 110 is connected to the balloon assembly 140 through a pipe joint.

In one embodiment, the drive handle 300 includes a drive motor 310, a power source 320, a circuit controller 350, and a gear set 380. The circuit controller 350 is configured to connect the over-current electronic protection element 331 in series with the control circuit to form the self-recovering circuit controller 350.

In one embodiment, as shown in fig. 22 and 23, the balloon assembly 140 includes a distal tip 141, a compliant balloon 142, a balloon developing ring 143, and a balloon support tube 144, the distal tip 141 is connected to the inner tube 110 by the balloon support tube 144, the balloon support tube 144 is provided with an inflation port 1441, and the compliant balloon 142 is sleeved outside the balloon support tube 144 and is communicated with the inner tube 110 sequentially through the inflation port 1441 and the balloon support tube 144; the balloon visualization ring 143 is disposed within the compliant balloon 142 and is sleeved outside of the balloon support tube 144 for anchoring the compliant balloon 142 in position in the vessel.

Further, in one embodiment, the outer diameter of the balloon support tubing 144 is greater than the outer diameter of the inner tube 110, and the balloon support tubing 144 is more compliant than the inner tube 110.

Further, in an embodiment, as shown in fig. 22 and 23, the end guiding head 141 includes a single-layer winding tube 1415, a metal wire 1411, a puncture preventing ball head 1412, a winding spring 1413 and a blocking ball head 1414, the single-layer winding tube 1415 is disposed in the inner tube 110 and is in clearance fit with the inner tube 110, one end of the metal wire 1411 is connected to the single-layer winding tube 1415 (may be welded), the other end of the metal wire 1411 passes through the balloon supporting tube 144 along the axial direction of the balloon supporting tube 144 and extends out of the balloon supporting tube 144 in a direction away from the inner tube 110, the blocking ball head 1414 is blocked at one end of the balloon supporting tube 144 away from the inner tube 110, and the blocking ball head 1414 can block the orifice of the balloon supporting tube 144. The anti-puncture ball head 1412 is connected to an end of the metal wire 1411 remote from the balloon support tube 144, and the anti-puncture ball head 1412 is used for preventing blood vessels from being punctured during the penetration pushing process. The coiled spring 1413 is arranged between the puncture-proof ball head 1412 and the blocking ball head 1414 and sleeved outside the metal guide wire 1411.

In one embodiment, as shown in fig. 24-26, aspiration tube assembly 200 includes a dilator tube 210 and an aspiration catheter 230. Aspiration catheter 230 is configured to be axially sleeved outside dilator tube 210. The suction catheter 230 is provided with a suction tube developing ring 231, a suction tube holder 232, and a knob type Y valve 233 coaxially disposed in this order. The end of dilator tube 210 remote from rotating basket 131 is provided with a dilator tab 220.

In one embodiment, the thrombus removal system of the present application further comprises: a variety of syringes (including 5mL syringe 234, 20mL syringe 235, and 50mL syringe 236), an extension tube 237, and a three-way valve 238. The syringe is used to inject fluid, create negative pressure to aspirate thrombus fragments, and to inflate the compliant balloon 142.

An example of the use of the thrombus removal system is shown below:

27-33, the preparation of balloon assembly 140 proceeds as follows:

after confirming no failure, using the saline and contrast agent mixture as the filling medium for the compliant balloon 142;

about 5mL of filling medium is used to fill 20mL syringe 235 and 5mL syringe 234, respectively;

three-way valve 238 is connected to the corresponding luer fitting (to the corresponding extension tube 237 if an extension tube 237 is used), and 20mL syringe and 5mL syringe 234 are connected to three-way valve 238;

Turning three-way valve 238 to close the 5mL syringe 234 connection port;

drawing air from the cavity of the compliant balloon 142 with the 20mL syringe liquid segment down, maintaining negative pressure until air bubbles cease to be generated in the 20mL syringe;

slowly releasing the syringe plunger to allow the filling medium to be sucked into the cavity of the compliant balloon 142, taking care not to actively inject the filling medium;

repeating the two steps for three times;

three-way valve 238 is turned to close the 20mL syringe 235 port;

balloon assembly 140 is ready.

(II) surgical procedure

Invasive instrument access: as shown in FIG. 33, the appropriate puncture sheath is selected to complete the prior access procedure and aspiration catheter 230 with dilator tube 210 is advanced over 0.035 "wire 1411 to the target vessel segment (distal of the pretreated thrombus segment);

position matching: as shown in fig. 34, the locking head 111 is unscrewed from the luer fitting of the drive handle 300, withdrawing the inner tube 110 until between the compliant balloon 142 and the rotating basket 131;

exposing the ends: as shown in fig. 35, the metal guidewire 1411 and dilator tube 210 are withdrawn, the aspiration catheter 230 is secured, and the assembled balloon assembly 140, rotating tube assembly 100, and drive handle 300 are advanced together along the aspiration catheter 230 lumen until the compliant balloon 142 is fully exposed to the aspiration catheter 230 (visualization point is desired to be observed under DSA);

Filling compliant balloon 142: as shown in fig. 36, three-way valve 238 is attached to inner tube 110, ready in accordance with the previous preparation of balloon assembly 140 (which preparation operation only needs to be performed 1 time), and filling medium is gently injected into compliant balloon 142 using 5mL syringe 234 until compliant balloon 142 reaches the desired diameter, turning three-way valve 238 to close inner tube 110;

aspiration catheter 230 is withdrawn: as shown in fig. 37, the drive handle 300 is fixed, the aspiration catheter 230 is retracted to the proximal end of the thrombus segment to be treated (the end near the drive handle 300), during which time the rotating basket 131 is completely released from the aspiration catheter 230, and during the retraction, a thrombolytic agent (the dose is determined by the physician according to the patient) is injected into the aspiration catheter 230 from the thrombolytic agent port;

auxiliary bolt breaking: as shown in fig. 38, the tail end of the inner tube 110 and the suction tube seat 232 are fixed, the driving handle 300 is started to be switched on, the driving handle 300 is moved to move back and forth, the speed regulating knob 390 can be regulated to accelerate or decelerate according to the requirement, and the step is mainly used for stirring thrombus and assisting thrombus breaking;

aspiration of thrombus: as shown in fig. 39, three-way valve 238 is turned to close 5mL syringe 234, using 20mL syringe 235, pressure relief compliant balloon 142 is depressurized until it collapses, actuating handle 300 is retracted, aspiration catheter 230 is retained, knob Y valve 233 is screwed on to the tail, 50mL syringe 236 is connected to the luer fitting for aspiration, and aspiration tube assembly 200 is retracted entirely outside the body after aspiration is completed.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the claims. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of the application should be determined from the following claims.

Claims

1. An invasive instrument comprising a functional element (130), a power source (320), an overcurrent protection module (330), a drive motor (310) and a flexible drive shaft (120), the flexible drive shaft (120) comprising an elastic helically wound spring tube section (121) and a rigid metal tube section (122), and the drive motor (310) being connected to the functional element (130) sequentially through the rigid metal tube section (122) and the elastic helically wound spring tube section (121),

The elastic spiral winding spring tube section (121) is in a spiral extension shape, and when the rotation resistance born by the functional element (130) is larger than a first preset resistance value, the elastic spiral winding spring tube section (121) can be elastically deformed in a torsion mode along the extension direction of the elastic spiral winding spring tube section and is in a contraction state;

the rotation resistance received by the functional element (130) is in positive correlation with the driving current of the driving motor (310) and is in one-to-one correspondence, the power supply (320) is electrically connected with the driving motor (310) through the overcurrent protection module (330), when the rotation resistance received by the functional element (130) is greater than a second preset resistance value, the driving current of the driving motor (310) is greater than a preset current value, and the overcurrent protection module (330) can be disconnected, so that the driving motor (310) stops outputting torque, wherein the second preset resistance value is greater than the first preset resistance value.

2. An invasive instrument according to claim 1, characterized in that the elastic spiral wound spring tube section (121) is constituted by a spiral wire, the section of the spiral wire of the elastic spiral wound spring tube section (121) being rectangular.

3. An invasiveness apparatus according to claim 2, wherein a cross-sectional width of the spiral wire of the elastic spiral spring tube section (121) is defined as a, a cross-sectional thickness of the spiral wire of the elastic spiral spring tube section (121) is defined as b, a pitch of the elastic spiral spring tube section (121) is defined as c, a pitch of the elastic spiral spring tube section (121) is defined as e, a clearance of the elastic spiral spring tube section (121) is defined as h, wherein e = a + h, a torsion cross-sectional coefficient of a cross-section of the elastic spiral spring tube section (121) perpendicular to a central axis is defined as Wt, a shear modulus of a material of the elastic spiral spring tube section (121) is defined as G, a cross-sectional angle of the elastic spiral spring tube section (121) is defined as Φ, a stored energy parameter of the elastic spiral spring tube section (121) is defined as θ, a polar moment of a cross-section of the elastic spiral spring tube section (121) is Ip, a torque received by the elastic spiral spring tube section (121) is defined as T, and a torsion coefficient received by the elastic spiral spring section (121) is defined as γ when the axial length of the spiral spring section (121) is defined as 0,

，

。

4. an invasive instrument according to claim 1, characterized in that the section of the spiral wire of the elastic spiral wound spring tube section (121) is trapezoidal or parallelogram.

5. The invasive instrument according to claim 1, wherein the over-current protection module (330) comprises an over-current electronic protection element (331) and a P-channel MOS transistor (332), the power supply (320) being connected in series with the over-current electronic protection element (331) and the drive motor (310) in sequence forming a first branch, and the power supply (320) being connected in series with the P-channel MOS transistor (332) forming a second branch;

when the current of the first branch is smaller than or equal to the preset current value, the over-current protection element (331) can be kept in a conducting state, the P-channel MOS transistor (332) is connected with a high level, and the driving motor (310) can normally operate;

when the current of the first branch is larger than the preset current value, the over-current electronic protection element (331) is in an off state, the P-channel MOS transistor (332) is connected with a low level, and the driving motor (310) stops running.

6. The invasive instrument according to claim 5, wherein the over-current protection module (330) further comprises an alarm element (333), the alarm element (333) being connected in series with the second branch, the second branch being turned on when the P-channel MOS transistor (332) is low, and the alarm element (333) being capable of issuing an alarm.

7. An invasive instrument according to claim 5, characterized in that the over-current protection element (331) is a self-restoring fuse.

8. The invasive instrument according to claim 1, further comprising a housing (340) and a circuit controller (350), the drive motor (310) and the circuit controller (350) being both disposed within the housing (340), and the circuit controller (350) being capable of controlling the drive motor (310) to be turned on and off.

9. The invasive instrument according to claim 1, characterized in that the elastic spiral wound spring tube section (121) comprises a first wound spring section (1211) and a second wound spring section (1212), the rigid metal tube section (122), the first wound spring section (1211) and the second wound spring section (1212) being coaxially arranged and connected in sequence in the axial direction, the bending stiffness of the second wound spring section (1212) being smaller than the bending stiffness of the first wound spring section (1211), the rigid metal tube section (122) being connected to the drive motor (310), the second wound spring section (1212) being connected to the functional element (130);

the invasive instrument further includes a self-lubricating sheath (150), the self-lubricating sheath (150) being wrapped around the rigid metal tube segment (122), the first coiled spring segment (1211), and the second coiled spring segment (1212).

10. The invasive instrument according to claim 9, wherein the first coiled spring section (1211) and the second coiled spring section (1212) are each composed of a helical wire, the cross-sectional area of the first coiled spring section (1211) helical wire being larger than the cross-sectional area of the second coiled spring section (1212) helical wire;

and/or the pitch of the first winding spring section (1211) is greater than the pitch of the second winding spring section (1212).