CN1810214A - Shape memory alloy driven miniature guide device for interventional blood vessel operation - Google Patents

Abstract

A guiding microdevice driven by a shape memory alloy for vascular interventional surgery relates to the application of the shape memory alloy (SMA) to the technical field of biomedical engineering. In order to solve the problem that the effectiveness and safety of the operation are limited in the manual control of catheter guidance in the existing interventional operation, the present invention includes a bias spring (1), at least three shape memory alloy springs (2) and at least Two connecting pieces (3), the bias spring (1) is a compression spring, the connecting piece (3) has a central through hole (3-1), and the biasing spring (1) passes through the center of the connecting piece (3) The through hole (3-1) is solidly connected with the central through hole (3-1), and the shape memory alloy spring (2) is evenly distributed on the outer side of the bias spring (1) and connected to the outer side of the connecting piece (3) respectively. The surface is solidly bonded together. The invention utilizes the characteristics of the shape memory alloy, which can actively control the moving direction of the catheter or the guide wire from the front end, and the positioning is accurate, thereby shortening the operation time, reducing the patient's pain, and improving the safety and success rate of the operation.

Description

Guided microdevices actuated by shape memory alloys for vascular interventional procedures

technical field

The invention relates to the application of shape memory alloy (SMA) to the technical field of biomedical engineering.

Background technique

Beginning in the early 1990s, interventional minimally invasive surgery techniques began to be applied to the treatment of vascular diseases. During the operation, the doctor inserts the catheter into the blood vessel, and under the guidance of the X-ray image, extends the catheter to the target position, and then completes certain medical procedures at the target position. Such interventional surgery can not only effectively solve vascular diseases, but also has many outstanding advantages, such as greatly shortening the operation time, greatly reducing the pain of patients, and shortening the recovery time from months to days. Due to these advantages, interventional surgery is adopted by more and more doctors and accepted by more and more patients. However, conventional vascular catheters use a manual control method, which relies on a mechanical offset mechanism, and the force transmission is limited by the frictional contact between the catheter and the tortuous vessel wall, which requires a long operating time; during catheter manipulation The force acting on the vessel wall is unpredictable, which can easily cause vessel damage; the turning radius of most catheters is fixed, and catheters with different turning radii are often replaced many times during the operation; and there are many branches of blood vessels, when the catheter is successfully Once the first or second branch is crossed, the physician loses control of the catheter, making the entire device unpredictable. This makes this kind of operation have great limitations in effectiveness and safety. Shape memory alloy is an alloy that can automatically restore its own plastic deformation to its original shape at a certain temperature. It also has excellent characteristics such as wear resistance, corrosion resistance, high damping and superelasticity. Therefore, it can meet the application requirements of various engineering and medicine, and is a very excellent functional material.

Contents of the invention

In order to solve the problem that the effectiveness and safety of the operation are limited by manual control of catheter guidance in the existing interventional surgery, a guide micro-device driven by shape memory alloy for vascular interventional surgery is provided. It can actively control the movement direction of the catheter or guide wire from the front end, and the positioning is accurate, thereby shortening the operation time, reducing the patient's pain, and improving the safety and success rate of the operation. The present invention comprises a bias spring, at least three shape memory alloy springs and at least two connecting pieces, the biasing spring is a compression spring, the connecting piece has a central through hole, and the biasing spring passes through the central through hole on the connecting piece and is connected with the connecting piece The central through hole is fixedly connected as a whole, and the shape memory alloy springs are evenly distributed on the outer side of the bias spring and are respectively fixedly connected with the outer surface of the connecting piece as a whole. The invention utilizes the characteristics of the shape memory alloy to simulate the movement mode of the natural snake, the SMA spring has the function of muscle, and the bias spring has the function of bone and muscle at the same time. The outer diameter of the present invention is about 1.2 millimeters, and it is installed on the front end of the catheter/guide wire. In the state of no power supply, due to the effect of the bias spring, the whole micro-device is close to a straight line state; in the state of power supply, one or more The SMA spring shrinks longitudinally, forcing the bias spring to bend and contract, thereby realizing the bending of the entire catheter guiding micro-device in different directions and radii, providing doctors with a safe and convenient treatment device for interventional operations.

Description of drawings

Fig. 1 is the front view of the overall structure of the present invention, Fig. 2 is the cross-sectional view of the overall structure of the present invention, Fig. 3 is the perspective view of the normal state of the overall structure of the present invention, Fig. 4 is the perspective view of the present invention in the bending state, Fig. 5 It is a schematic diagram of the application of the present invention in the process of vascular surgery.

Detailed ways

Specific embodiment one: (see Fig. 1-Fig. 5) this embodiment is made up of bias spring 1, three shape memory alloy (SMA) springs 2 and two connectors 3, bias spring 1 is a compression spring, connector 3 has a central through hole 3-1, the bias spring 1 passes through the central through hole 3-1 on the two connectors 3 and is firmly connected with the central through hole 3-1, and the three shape memory alloy springs 2 are uniform are distributed on the outer side of the bias spring 1 and fixedly connected with the outer surface of the connecting piece 3 as a whole. Because the tensile strength of NiTi alloy is above 1000Mpa, the elongation is above 20%, the fatigue life is ¹⁰⁷ times, the damping characteristic is 10 times higher than that of ordinary springs, and its corrosion resistance is better than the best medical stainless steel at present. The bias spring described in the method can be selected as a shape memory alloy material based on nickel titanium (NiTi). Working principle: When the SMA spring 2 is in the energized and heated state, the SMA spring 2 undergoes a phase change, generating a strong contraction force, so that the end of the catheter or guide wire turns to the vascular branch in the specified direction according to the required angle and radius (as shown in Figure 4 and Figure 5 shown); when these SMA springs 2 are in the power-off cooling state, the SMA springs 2 undergo a reverse phase transition, and the contraction force disappears. Under the action of the bias spring 1, the micro-device returns to a straight state.

Specific embodiment 2: (see Fig. 1-Fig. 5) The difference between this embodiment and specific embodiment 1 is that the connecting part on the connecting piece 3 and the bias spring 1 is a concave arc surface 1-1, The shape and size of the concave arc surface 1-1 match the outer diameter of the bias spring 1. Other compositions and connections are the same as in the first embodiment. Because the shape and size of the inner concave arc surface 1-1 match the outer diameter of the bias spring 1, the contact area between the connector 3 and the bias spring 1 is the largest, and when the SMA spring 2 undergoes a phase change, the present invention is guaranteed Action reliability.

Specific embodiment 3: (see Fig. 1-Fig. 5) The difference between this embodiment and specific embodiment 1 or 2 is that the connector 3 is an insulating material or a conductive material coated with an insulating film on the outer surface. Other compositions and connections are the same as those in Embodiment 1 or Embodiment 2. This embodiment avoids the problem that the performance of the whole micro-device is affected by the conduction of electricity between the SMA springs or between the SMA spring and the bias spring.

Embodiment 4: (see Fig. 1-Fig. 5) The difference between this embodiment and Embodiment 1, 2 or 3 is that the bias spring 1 is bonded to the central through hole 3-1 on the connector 3 as Integral, the shape memory alloy springs 2 are respectively bonded to the outer surface of the connector 3 as a whole. Other compositions and connections are the same as those in Embodiment 1, 2 or 3.

Specific embodiment five: (referring to Fig. 1-Fig. 5) the difference between this embodiment and specific embodiment one, two, three or four is that it has increased two connectors 3 again, and the added two connectors 3 are along The central line direction is placed at intervals in the middle of the device. Other compositions and connections are the same as those in Embodiment 1, 2, 3 or 4.

The connecting piece 3 of the present invention can be provided in multiples as required, forming a serpentine-like structure, as long as it can meet the requirements of use, it is within the scope of protection of this patent.

Specific embodiment six: (referring to Fig. 1-Fig. 5) the difference between this embodiment and specific embodiment one, two, three, four or five is that it has increased the outer packaging silicone tube 4, and the outer packaging silicone tube 4 is set in the The outside of the shape memory alloy spring 2. Other compositions and connections are the same as those in Embodiment 1, 2, 3, 4 or 5. The outer packaging silicone tube 4 described in this embodiment can function as an insulation and protection device.

When in use, the two ends of each section of each SMA spring can be energized and heated respectively, and controlled by adjusting the supply current. The current is adjustable, and the current value ranges from 1 mA to 150 mA. A complete cycle of motion in the present invention can be decomposed into two processes: contraction bending process and diastolic straightening process: contraction bending process: ① power on a certain SMA spring 2 and heat it, and judge whether the bending direction of the device is in line with the direction of the blood vessel branch 6 Consistent; ②Adjust and heat one or two SMA springs 2, so that the bending direction of the device is consistent with the direction of the blood vessel branch 6; ③Adjust the power supply current to control the bending radius (rotation angle), so that the front end of the device enters the designated blood vessel branch 6; ④ SMA spring 2 keeps warm, waiting for the feeding of catheter/guide wire 5. Diastolic stretching process: ⑤ SMA spring 2 cools down, and under the action of bias spring 1, SMA spring 2 gradually relaxes and elongates. When it is lower than the martensitic phase transition temperature, under the action of bias spring 1, SMA spring 2 recovers In the initial state, the whole device returns to the initial approximate linear state. So far, the device has completed the guiding and steering process of a blood vessel branch 6 (as shown in Fig. 4 and Fig. 5). By repeating the above steps, the present invention can guide the catheter/guide wire 5 to enter any vascular branch 6 in the human vascular system within the allowable diameter range, and assist doctors to complete various vascular operations.

Claims (7)

1, the guide miniature device that is used for the marmem driving of blood vessel insertion type operation, it is characterized in that it comprises bias spring (1), at least three shape memory alloy springs (2) and at least two connectors (3), bias spring (1) is the compression spring, connector (3) has central through hole (3-1), bias spring (1) passes the central through hole (3-1) on the connector (3) and is fixed with one with central through hole (3-1), and shape memory alloy spring (2) is evenly distributed on the outside of bias spring (1) and is fixed with one with the outer surface of connector (3) respectively.

2, the guide miniature device that is used for the marmem driving of blood vessel insertion type operation according to claim 1, it is characterized in that the junction with bias spring (1) on the described connector (3) is interior concaved circular cambered surface (1-1), interior concaved circular cambered surface (1-1) shape and size match with the external diameter of bias spring (1).

3, the guide miniature device that is used for the marmem driving of blood vessel insertion type operation according to claim 1 and 2, it is characterized in that the central through hole (3-1) on described bias spring (1) and the connector (3) is bonded as one, described shape memory alloy spring (2) is bonded as one with the outer surface of connector (3) respectively.

4, the guide miniature device that is used for the marmem driving of blood vessel insertion type operation according to claim 3 is characterized in that described connector (3) is an insulant.

5, the guide miniature device that is used for the marmem driving of blood vessel insertion type operation according to claim 3 is characterized in that the conductive material of described connector (3) for outer surface plating dielectric film.

6, the guide miniature device that drives according to claim 1,2, the 4 or 5 described marmems that are used for the operation of blood vessel insertion type, it is characterized in that it has increased by two connectors (3) again, two connectors (3) that increased are put the middle part at this device along the centerline direction compartment of terrain.

7, the guide miniature device that is used for the marmem driving of blood vessel insertion type operation according to claim 6, it is characterized in that it has increased outer package silica gel tube (4), outer package silica gel tube (4) is sleeved on the outside of described shape memory alloy spring (2).

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