A microfluidic array-based variable stiffness interventional catheter

Abstract

This invention relates to the field of medical device technology, and in particular to a variable stiffness interventional catheter based on a microfluidic array, comprising: a handle, a control component, and a catheter body. The handle is connected to the control component, and the control component is fixedly connected to the proximal end of the catheter body. The catheter body has an axially extending main working chamber inside. The catheter body wall has a skeleton layer for limiting radial expansion, and a plurality of axially extending microfluidic cavities are formed in the gaps of the skeleton layer. A control switch electrically connected to the control component is installed at the upper end of the handle. The control component is used to inject or discharge pressure medium into the microfluidic cavities. This invention can adjust the overall stiffness of the catheter in real time and reversibly by injecting / discharging pressure medium into the microfluidic cavities. During delivery and navigation, the catheter body remains fully flexible, possessing excellent compliance and tracking ability, and can safely pass through ultra-torsional vascular paths.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a variable stiffness interventional catheter based on a microfluidic array. Background Technology

[0002] In cardiovascular interventional procedures (such as percutaneous coronary intervention (PCI) and cardiac electrophysiological ablation) and neurointerventional procedures, the interventional catheter is the core channel for instrument delivery and manipulation. Its performance directly determines the success rate and safety of the procedure. These procedures face a common and critical technical contradiction: the extreme tortuosity of the pathway requires the catheter to have excellent flexibility, while the treatment operation after reaching the lesion requires the catheter to have extremely high support rigidity.

[0003] Specifically, during the navigation phase, the catheter must be flexible enough to conform to the complex and fragile vascular anatomy and safely and non-invasively reach the target location. However, once in place, the catheter needs to immediately transform into a rigid "track" to provide stable support for subsequent critical procedures: for example, stably delivering and releasing stents in PCI, ensuring stable contact between the ablation catheter and tissue in electrophysiological procedures, or preventing catheter displacement or prolapse during instrument delivery. This "soft-to-rigid" and "rigid-on-demand" performance requirement cannot be met by a single fixed-rigidity catheter.

[0004] To address this contradiction, several solutions have been proposed in existing technologies, but all of them have significant drawbacks: Pull-wire (steel wire traction) controllable bending catheter: The distal end of the catheter is actively bent by pulling the control wire at the end. However, this technology can only change the local bending shape of the catheter and cannot achieve uniform rigidity of the entire catheter or a large area. When providing support, the unreinforced proximal part may still be soft and bend, resulting in a "whiplash effect". The pushing force transmission efficiency is low and the control is inaccurate.

[0005] Standard graded stiffness catheters: These catheters are constructed by splicing or fusing materials of varying stiffness from proximal to distal, with the stiffness distribution fixed at the factory. This design prevents real-time, active stiffness adjustment during surgery. Surgeons can only select the catheter based on preoperative predictions. If the actual situation during surgery differs from the prediction (e.g., the degree of vascular tortuosity exceeds expectations or support is insufficient), adjustments cannot be made, necessitating catheter replacement, which increases surgical time and risk.

[0006] Balloon or fluid-pressurized rigid catheters: By integrating an inflatable lumen within the catheter wall, fluid pressure is used to expand and harden it. After inflation, the outer diameter of the catheter will increase significantly. In the already narrow blood vessel lumen, this can easily cause blood flow obstruction, intimal damage, or even perforation of the blood vessel wall, seriously threatening the safety of the operation.

[0007] To address the aforementioned problems, this invention proposes a variable stiffness interventional catheter based on a microfluidic array, which can achieve rapid, reversible, and on-demand adjustment from highly compliant to highly rigid while maintaining a basically constant outer diameter. Summary of the Invention

[0008] To address the problems existing in the background art, this invention proposes a variable stiffness interventional catheter based on a microfluidic array.

[0009] The variable stiffness interventional catheter based on a microfluidic array provided in this application adopts the following technical solution: A variable stiffness interventional catheter based on a microfluidic array includes a handle, a control component, and a catheter body. The handle is connected to the control component, which is fixedly connected to the proximal end of the catheter body. The catheter body has an axially extending main working chamber inside. The catheter body wall has a skeleton layer for limiting radial expansion, and a plurality of axially extending microfluidic cavities are formed in the gaps of the skeleton layer. A control switch electrically connected to the control component is installed at the upper end of the handle. The control component is used to inject or discharge pressure medium into the microfluidic cavities. When pressure medium is injected, the microfluidic cavities generate internal stress under the constraint of the skeleton layer, thereby increasing the bending stiffness of the catheter body.

[0010] Furthermore, the catheter body includes a proximal end and a distal end, with the microfluidic cavity extending through the interior of the proximal end.

[0011] Furthermore, the control component includes a housing, a connecting unit, an adjusting unit, a sealing plate, and an injection tube. The housing has a rectangular hollow structure and is installed at the end of the handle. The connecting unit is installed at the front end of the housing, the adjusting unit is installed in the middle of the housing via a bearing, the sealing plate is installed at the rear end of the housing, and the injection tube is installed at the lower end of the sealing plate. The injection tube is connected to the interior of the adjusting unit, and the rear end of the connecting unit passes through the middle of the sealing plate and extends to the rear side of the sealing plate.

[0012] Furthermore, the communication unit includes a mounting plate, a communication pipe, and a connecting pipe. The mounting plate is installed at the front end of the housing by screws, and the communication pipe is installed at the rear end of the mounting plate. An operation hole communicating with the main working chamber is opened in the middle of the communication pipe. The communication pipe passes through the middle of the sealing plate and extends to the rear side of the sealing plate. Through holes are evenly opened on the mounting plate, and a connecting pipe is installed on the through holes. The connecting pipe is connected to the plug connector.

[0013] Furthermore, the adjustment unit includes a rotating ring, a guide hole, a bevel gear, and a limiting frame. The rotating ring is installed inside the housing via a bearing. The rotating ring has an L-shaped cross-section and a circular ring structure. Guide holes corresponding to the through holes are evenly opened on the front end face of the rotating ring. A bevel gear is fixedly installed in the middle of the outer side of the rotating ring. Limiting frames are symmetrically installed on the outer side of the rotating ring, and locking grooves are evenly opened on the limiting frames.

[0014] Furthermore, the front end face of the rotating ring is evenly distributed with control zone one and control zone two, which are arranged alternately. The total number of control zone one and control zone two corresponds to the number of microfluidic cavities. Control zone one has two guide holes, and control zone two has one guide hole.

[0015] Furthermore, the handle is also equipped with a drive unit and a clamping unit. The drive unit meshes with a bevel gear, and the clamping unit is in close contact with the limit frame. The control switch is electrically connected to the drive unit.

[0016] Furthermore, the drive unit includes a drive motor, a rotating shaft, and a connecting gear. The drive motor is installed inside the handle, the rotating shaft is installed on the output shaft of the drive motor, and the connecting gear is fixedly installed on the rotating shaft. The connecting gear meshes with a bevel gear.

[0017] Furthermore, the clamping unit includes a fixed sleeve, a sliding rod, and a compression spring. The fixed sleeve is installed at the end of the handle, and the sliding rod is slidably arranged inside the fixed sleeve. The sliding rod has a T-shaped structure and a compression spring is provided on the sliding rod. The outer end of the sliding rod is an arc-shaped surface that fits against the limit frame, and locking protrusions are evenly arranged on the arc-shaped surface. The locking protrusions cooperate with the locking grooves.

[0018] Beneficial effects Compared with the prior art, the present invention provides a variable stiffness interventional catheter based on a microfluidic array, which has the following advantages: 1. In this invention, by injecting / expelling a pressure medium into the microfluidic chamber, the overall stiffness of the catheter can be adjusted in real time and reversibly. During delivery and navigation, the catheter body remains in a fully soft state, possessing excellent flexibility and tracking ability, and can safely pass through ultra-torsional vascular paths. When the target point is reached and instrument delivery or stabilization operation is required, it can instantly switch to a high-rigidity state, providing strong axial support and bending resistance, effectively preventing catheter displacement and ensuring accurate delivery of therapeutic instruments, thus optimizing the surgical procedure.

[0019] 2. In this invention, through the precise design of the rotating ring in the control component, the catheter body can achieve three levels of stiffness adjustment: "fully soft - semi-hard - fully hard". Doctors can select the most suitable stiffness mode according to the specific needs of vascular anatomy, lesion type and surgical procedure. While providing necessary support, the overall compliance of the catheter body is preserved to the greatest extent, thus realizing personalized and refined surgical operation.

[0020] 3. In this invention, after the microfluidic chamber is pressurized inside, its tendency to expand outward is strictly limited by the pre-embedded high-modulus skeleton, which forces the expansion force to be converted into internal stress that tightens the tube wall material, so that the stiffness of the catheter body can be increased by orders of magnitude, while the outer diameter of the catheter body only changes very little, thereby avoiding the risk of blood flow obstruction, damage to the vascular endothelium or perforation caused by the thickening of the catheter body. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Figure 1 This is a three-dimensional structural diagram of this application.

[0023] Figure 2 This is a three-dimensional cross-sectional structural diagram of this application.

[0024] Figure 3 This is a three-dimensional structural diagram of the handle and control components of this application.

[0025] Figure 4 This is a rear view of the area between the handle and the control components of this application.

[0026] Figure 5 This is a cross-sectional structural diagram of the handle and control components of this application.

[0027] Figure 6 This is a cross-sectional structural diagram of the control component of this application.

[0028] Figure 7 This is a three-dimensional structural diagram of the connected unit in this application.

[0029] Figure 8 This is a three-dimensional structural diagram of the adjustment unit of this application.

[0030] Figure 9 This is a schematic diagram of the planar structure of the adjustment unit of this application.

[0031] Figure 10 This is a cross-sectional structural diagram of the handle, drive unit, and clamping unit of this application.

[0032] Explanation of reference numerals in the attached drawings: 1. Handle; 11. Control switch; 12. Drive unit; 121. Drive motor; 122. Rotating shaft; 123. Connecting gear; 13. Clamping unit; 131. Fixing sleeve; 132. Sliding rod; 133. Compression spring; 2. Control assembly; 21. Housing; 22. Connecting unit; 221. Mounting plate; 222. Connecting pipe; 223. Connecting pipe; 23. Adjusting unit; 231. Rotating ring; 232. Guide hole; 233. Bevel gear; 234. Limiting frame; 24. Sealing plate; 25. Injection pipe; 3. Conduit body; 31. Main working chamber; 32. Microfluidic chamber; 33. Connector. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Please see Figures 1-10 This invention provides a variable stiffness interventional catheter based on a microfluidic array, comprising a handle 1, a control component 2, and a catheter body 3. The handle 1 is connected to the control component 2, and the control component 2 is fixedly connected to the proximal end of the catheter body 3. The catheter body 3 has an axially extending main working chamber 31 inside. The catheter body 3 has a skeleton layer inside its wall for limiting radial expansion, and a plurality of axially extending microfluidic cavities 32 are formed in the gaps of the skeleton layer. A control switch 11 electrically connected to the control component 2 is installed at the upper end of the handle 1. The control component 2 is used to inject or discharge pressure medium into the microfluidic cavities 32. When pressure medium is injected, the microfluidic cavities 32 generate internal stress under the constraint of the skeleton layer, thereby increasing the bending stiffness of the catheter body 3.

[0035] In the above technical solution, in cardiovascular (such as PCI, electrophysiology) or neurointerventional surgery, the catheter body 3 needs to have excellent flexibility to reach the lesion through tortuous blood vessels; however, once it reaches the position, it needs to have extremely high support to deliver instruments (such as stents, ablation catheters) or prevent displacement. Therefore, when the catheter body 3 reaches the preset position, the control switch 11 can inject a medium into the microfluidic cavity 32 through the control component 2. The medium injected into the microfluidic cavity 32 can be physiological saline (the safest) or a high-viscosity fluid. Under the pressurization of the medium, the catheter body 3 changes from a soft state to a rigid state, which facilitates the accurate delivery of subsequent instruments.

[0036] The inner layer of the catheter body 3 is lined with PTFE to reduce friction. The middle layer of the catheter body 3 is a polyurethane matrix with an embedded skeleton layer. Several microfluidic cavities 32 extending axially are formed in the gaps of the skeleton layer. The microfluidic cavities 32 have a crescent-shaped structure. The outer layer of the catheter body 3 is wrapped with a thin layer of polyurethane, which plays a role in sealing and protection. Under depressurization, the microfluidic cavities 32 are flat, the polyurethane is soft, and the catheter as a whole is soft. Under pressure, the microfluidic cavities 32 expand, but are restricted by the skeleton, which causes the polyurethane chains to tighten and the rigidity of the catheter body 3 is improved. The catheter body 3 adopts a multi-layer co-extrusion process to form a composite tube blank. When the microfluidic cavity 32 is pressurized, the outer diameter of the catheter body 3 does not expand (or the expansion rate is <5%), ensuring the safety of the operation.

[0037] See Figures 1-2 As shown, in this preferred embodiment, the catheter body 3 includes a proximal end and a distal end, and the microfluidic cavity 32 is disposed through the interior of the proximal end.

[0038] In the above technical solution, the side of the catheter body 3 closest to the handle 1 is the proximal end, and the side closest to the end of the catheter body 3 is the distal end. This allows for selective hardening of the proximal end to improve strong support, while the distal end remains soft to avoid the risk of perforation.

[0039] See 3- Figure 9 As shown, as a preferred technical solution of this embodiment, the control component 2 includes a housing 21, a connecting unit 22, an adjusting unit 23, a sealing plate 24, and an injection tube 25. The housing 21 has a rectangular hollow structure and is installed at the end of the handle 1. The connecting unit 22 is installed at the front end of the housing 21, the adjusting unit 23 is installed in the middle of the housing 21 through a bearing, the sealing plate 24 is installed at the rear end of the housing 21, and the injection tube 25 is installed at the lower end of the sealing plate 24. The injection tube 25 is connected to the interior of the adjusting unit 23, and the rear end of the connecting unit 22 passes through the middle of the sealing plate 24 and extends to the rear side of the sealing plate 24.

[0040] In the above technical solution, the injection tube 25 is connected to the pressure pump. When it is necessary to adjust the hardness of the catheter body 3, the pressure pump drives the medium to be injected into the adjustment unit 23 through the injection tube 25. The adjustment unit 23 can adjust the flow rate of the medium. The medium is then injected into the microfluidic cavity 32 through the connecting unit 22, thereby changing the hardness of the catheter body 3.

[0041] It should be noted that the adjustment unit 23 can achieve three levels of conditions. When the adjustment unit 23 and the connecting unit 22 are completely closed, the flow rate of the medium is zero, the medium will not enter the microfluidic cavity 32, and the catheter body 3 is in a fully soft state. When the channel between the adjustment unit 23 and the connecting unit 22 is partially open, only a portion of the microfluidic cavity 32 will be filled with the medium, and the catheter body 3 is in a semi-hard state. When the channel between the adjustment unit 23 and the connecting unit 22 is fully open, all microfluidic cavities 32 will be filled with the medium, and the catheter body 3 is in a fully hard state.

[0042] See Figure 7 As shown, in this preferred embodiment, the communication unit 22 includes a mounting plate 221, a communication pipe 222, and a connecting pipe 223. The mounting plate 221 is installed at the front end of the housing 21 by screws, and the communication pipe 222 is installed at the rear end of the mounting plate 221. An operation hole communicating with the main working chamber 31 is opened in the middle of the communication pipe 222. The communication pipe 222 passes through the middle of the sealing plate 24 and extends to the rear side of the sealing plate 24. Through holes are evenly opened on the mounting plate 221, and the connecting pipe 223 is installed on the through holes. The connecting pipe 223 is connected to the plug 33.

[0043] See Figure 8 As shown, as a preferred technical solution of this embodiment, the adjustment unit 23 includes a rotating ring 231, a guide hole 232, a bevel gear 233, and a limiting frame 234. The rotating ring 231 is installed inside the housing 21 through a bearing. The rotating ring 231 is an L-shaped annular structure. The front end face of the rotating ring 231 is evenly provided with guide holes 232 corresponding to the through holes. The bevel gear 233 is fixedly installed in the middle of the outer side of the rotating ring 231. The limiting frame 234 is symmetrically installed on the outer side of the rotating ring 231. The limiting frame 234 is evenly provided with locking grooves.

[0044] To prevent leakage of the pressurized medium, a first sealing ring is provided at the mating sealing surface of the rotating ring 231 and the connecting unit 22, and a second sealing ring is provided at the connection between the sealing plate 24 and the rotating ring 231. The sealing rings are preferably O-rings (not shown in the attached drawings). The first sealing ring provides a dynamic seal when the rotating ring 231 rotates relative to the other side; the second sealing ring provides a static seal at the connection point. An axial clamping force is applied to the rotating ring 231 by the preload of the compression spring 133 to ensure reliable sealing.

[0045] See Figure 9 As shown, in this preferred embodiment, the front end face of the rotating ring 231 is evenly distributed with a control zone 1 and a control zone 2, which are arranged alternately. The total number of control zones 1 and 2 corresponds to the number of microfluidic cavities 32. Two guide holes 232 are opened on the control zone 1, and one guide hole 232 is opened on the control zone 2.

[0046] In the above technical solution, the rotating ring 231 can rotate at a fixed angle. Three rotation points (a, b, c) are provided on both control zone one and control zone two. Control zone one has guide holes 232 at points b and c, while control zone two only has a guide hole at point c. In the initial state, the connecting pipe 223 corresponds to rotation point a on both control zone one and control zone two. At this time, the end of the connecting pipe 223 is closed, and the medium will not flow into the microfluidic cavity 32; the conduit body 3 is in a fully soft state. When the rotating ring 231 rotates a certain angle, the connecting pipe... 223 corresponds to the rotation point b on control zone one and control zone two. At this time, the connecting pipe 223 corresponding to control zone one is connected to the guide hole 232, so that part of the microfluidic cavity 32 is filled with medium and the conduit body 3 is in a semi-hard state. When the rotating ring 231 rotates a certain angle again, the connecting pipe 223 corresponds to the rotation point c on control zone one and control zone two. At this time, all the guide holes 232 on control zone one and control zone two are connected to the connecting pipe 223, all the microfluidic cavities 32 are filled with medium and the conduit body 3 is in a fully hard state.

[0047] See Figure 10 As shown, as a preferred technical solution in this embodiment, the handle 1 is also equipped with a drive unit 12 and a clamping unit 13. The drive unit 12 meshes with the bevel gear 233, and the clamping unit 13 is in close contact with the limit frame 234. The control switch 11 is electrically connected to the drive unit 12.

[0048] In the above technical solution, the drive unit 12 can achieve the purpose of accurately adjusting the rotating ring 231, and the clamping unit 13 can perform the purpose of pressing and limiting the rotating ring 231 to ensure that the rotating ring 231 rotates at the same angle each time.

[0049] See Figure 10 As shown, as a preferred technical solution of this embodiment, the drive unit 12 includes a drive motor 121, a rotating shaft 122 and a connecting gear 123. The drive motor 121 is installed inside the handle 1. The rotating shaft 122 is installed on the output shaft of the drive motor 121. The connecting gear 123 is fixedly installed on the rotating shaft 122. The connecting gear 123 meshes with the bevel gear 233.

[0050] See Figure 10As shown, as a preferred technical solution of this embodiment, the clamping unit 13 includes a fixed sleeve 131, a sliding rod 132 and a compression spring 133. The fixed sleeve 131 is installed at the end of the handle 1. The sliding rod 132 is slidably arranged inside the fixed sleeve 131. The sliding rod 132 has a T-shaped structure. The compression spring 133 is provided on the sliding rod 132. The outer end of the sliding rod 132 is an arc-shaped surface that fits against the limiting frame 234. Locking protrusions are evenly arranged on the arc-shaped surface, and the locking protrusions cooperate with the locking grooves.

[0051] In the above technical solution, when it is necessary to control the catheter body 3 to be in a semi-rigid state, press the control switch 11 so that the drive motor 121 drives the rotating ring 231 to rotate at an angle through gear transmission. At the same time, the locking protrusion at the end of the sliding rod 132 is pushed up and makes a clicking sound with the locking groove. After the rotating ring 231 completes the fixed angle rotation, the locking protrusion immediately resets and locks with the locking groove, thereby completing the purpose of pressing the rotating ring 231.

[0052] Combining the above structure, the variable stiffness interventional catheter based on a microfluidic array provided by this invention operates according to the following steps: S1: Flexible Navigation and Positioning In the initial stage of the operation, the catheter body 3 is in a depressurized state. At this time, no pressure medium is filled in any of the microfluidic cavities 32. The microfluidic cavities 32 are flat and the catheter wall made of polyurethane matrix remains soft, giving the catheter body 3 excellent overall flexibility. The operator inserts a guidewire through the main working lumen 31. With the guidance of the guidewire and the assistance of imaging equipment, the distal end of the soft catheter body 3 is safely passed through the tortuous vascular path until its tip accurately reaches the lesion or target surgical site.

[0053] S2: Position Confirmation and Adjustment Preparation Once the distal end of the catheter body 3 reaches the preset position, the operator confirms its position using imaging methods (such as X-ray angiography). Then, the operator prepares to activate the stiffness adjustment function. Based on the specific support requirements of the surgery, the operator selects the corresponding stiffness mode (fully soft, semi-hard, or fully hard) through the control switch 11 on the handle 1.

[0054] S3: Selective stiffness adjustment When the operator presses the control switch 11, the switch signal drives the drive unit 12 inside the handle 1 to operate. The drive motor 121, through the meshing of the connecting gear 123 and the bevel gear 233, precisely drives the rotating ring 231 to rotate at a specific angle. The rotation of the rotating ring 231 causes the guide hole 232 on its front end face to have different alignment relationships with the connecting pipe 223 of the connecting unit 22. At the same time, the external pressure pump injects pressure media such as physiological saline into the system through the injection pipe 25. The media flows through the adjustment unit 23 and selectively enters the microfluidic cavities 32 of different groups according to the current angular position of the rotating ring 231. If the "fully soft" mode is selected, the rotating ring 231 is in the initial position, all the guide holes 232 are misaligned with the connecting tube 223, the medium cannot enter any microfluidic cavity, and the conduit body 3 remains fully soft.

[0055] If the "semi-hard" mode is selected, the rotating ring 231 is rotated to the middle position, and only the connecting pipe 223 corresponding to "Control Zone 1" is connected to the guide hole 232, so that a part (such as half) of the microfluidic cavity 32 is pressurized.

[0056] If the "Full Hard" mode is selected, the rotating ring 231 rotates to the final position, and the connecting pipes 223 corresponding to the "Control Zone 1" and "Control Zone 2" are connected to the guide hole 232, so that all microfluidic cavities 32 are pressurized. After each rotation to the final position, the locking unit 13 locks the rotating ring by the cooperation of the locking protrusion and the locking groove to ensure the stability of the state.

[0057] S4: Constrained Expansion and Rigid Support After the pressure medium fills the target microfluidic cavity 32, it attempts to push the soft polyurethane cavity wall outward to restore its circular cross-section. However, this expansion is circumferentially restricted by the high-modulus PEEK or nylon skeleton pre-embedded in the tube wall. This "restricted expansion" generates huge circumferential and axial tensions inside the catheter wall, forcing the originally loose polyurethane polymer chains to be strongly tightened. The macroscopic manifestation is that the bending stiffness of the catheter body 3 increases sharply, instantly changing from a flexible state to a "rigid tube" state with excellent bending and torsion resistance. This provides a stable support channel for the subsequent delivery of stents, balloons, ablation catheters and other instruments through the main working cavity 31, and effectively prevents the catheter from shifting during operation.

[0058] S5: Task Completion and Status Recovery After the core surgical steps (such as stent release and ablation) are completed, the operator depressurizes the system again by controlling switch 11. The pressure medium flows back from the microfluidic cavity 32 through the original path, the pressure in the microfluidic cavity 32 is released, the polyurethane material elastically recovers, and the microfluidic cavity 32 returns to its flat shape. The overall stiffness of the catheter body 3 decreases rapidly and returns to its initial soft state. At this time, the catheter can be safely and smoothly withdrawn from the vascular path, completing all surgical operations.

[0059] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A variable stiffness interventional catheter based on a microfluidic array, characterized in that, include: The device comprises a handle (1), a control component (2), and a catheter body (3). The handle (1) is connected to the control component (2), and the control component (2) is fixedly connected to the proximal end of the catheter body (3). The catheter body (3) has an axially extending main working chamber (31) inside. The catheter body (3) has a skeleton layer inside its wall for limiting radial expansion, and a plurality of axially extending microfluidic cavities (32) are formed in the gaps of the skeleton layer. The upper end of the handle (1) is equipped with a control switch (11) electrically connected to the control component (2). The control component (2) is used to inject or discharge pressure medium into the microfluidic cavity (32). When pressure medium is injected, the microfluidic cavity (32) generates internal stress under the restriction of the skeleton layer, which increases the bending stiffness of the catheter body (3).

2. The variable stiffness interventional catheter based on a microfluidic array according to claim 1, characterized in that: The catheter body (3) includes a proximal end and a distal end, and the microfluidic cavity (32) is disposed through the proximal end.

3. The variable stiffness interventional catheter based on a microfluidic array according to claim 2, characterized in that: The control component (2) includes a housing (21), a communication unit (22), an adjustment unit (23), a sealing plate (24), and an injection tube (25). The housing (21) has a rectangular hollow structure and is installed at the end of the handle (1). The communication unit (22) is installed at the front end of the housing (21). The adjustment unit (23) is installed in the middle of the housing (21) through a bearing. The sealing plate (24) is installed at the rear end of the housing (21). The injection tube (25) is installed at the lower end of the sealing plate (24). The injection tube (25) is connected to the inside of the adjustment unit (23). The rear end of the communication unit (22) passes through the middle of the sealing plate (24) and extends to the rear side of the sealing plate (24).

4. The variable stiffness interventional catheter based on a microfluidic array according to claim 3, characterized in that: The communication unit (22) includes a mounting plate (221), a communication pipe (222), and a connecting pipe (223). The mounting plate (221) is installed at the front end of the housing (21) by screws. The communication pipe (222) is installed at the rear end of the mounting plate (221). An operation hole communicating with the main working chamber (31) is opened in the middle of the communication pipe (222). The communication pipe (222) passes through the middle of the sealing plate (24) and extends to the rear side of the sealing plate (24). Through holes are evenly opened on the mounting plate (221). The connecting pipe (223) is installed on the through holes. The connecting pipe (223) is connected to the plug (33).

5. A variable stiffness interventional catheter based on a microfluidic array according to claim 4, characterized in that: The adjustment unit (23) includes a rotating ring (231), a guide hole (232), a bevel gear (233), and a limiting frame (234). The rotating ring (231) is installed inside the housing (21) through a bearing. The rotating ring (231) is an L-shaped circular ring structure. The front end face of the rotating ring (231) is evenly provided with guide holes (232) corresponding to the through holes. The bevel gear (233) is fixedly installed in the middle of the outer side of the rotating ring (231). The limiting frame (234) is symmetrically installed on the outer side of the rotating ring (231). The limiting frame (234) is evenly provided with locking grooves.

6. A variable stiffness interventional catheter based on a microfluidic array according to claim 5, characterized in that: The rotating ring (231) has a control zone 1 and a control zone 2 evenly distributed on its front end surface. The control zone 1 and control zone 2 are arranged alternately. The total number of control zone 1 and control zone 2 corresponds to the number of microfluidic cavities (32). Two guide holes (232) are opened on the control zone 1 and one guide hole (232) is opened on the control zone 2.

7. A variable stiffness interventional catheter based on a microfluidic array according to claim 6, characterized in that: The handle (1) is also equipped with a drive unit (12) and a clamping unit (13). The drive unit (12) meshes with the bevel gear (233), and the clamping unit (13) is in close contact with the limit frame (234). The control switch (11) is electrically connected to the drive unit (12).

8. A variable stiffness interventional catheter based on a microfluidic array according to claim 7, characterized in that: The drive unit (12) includes a drive motor (121), a rotating shaft (122), and a connecting gear (123). The drive motor (121) is installed inside the handle (1). The rotating shaft (122) is installed on the output shaft of the drive motor (121). The connecting gear (123) is fixedly installed on the rotating shaft (122). The connecting gear (123) meshes with the bevel gear (233).

9. A variable stiffness interventional catheter based on a microfluidic array according to claim 8, characterized in that: The clamping unit (13) includes a fixed sleeve (131), a sliding rod (132), and a compression spring (133). The fixed sleeve (131) is installed at the end of the handle (1). The sliding rod (132) is slidably arranged inside the fixed sleeve (131). The sliding rod (132) has a T-shaped structure. The compression spring (133) is provided on the sliding rod (132). The outer end of the sliding rod (132) is an arc-shaped surface that fits against the limiting frame (234). Locking protrusions are evenly arranged on the arc-shaped surface. The locking protrusions cooperate with the locking groove.

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