CN112891711B - Medical intervention guide wire with controllable steering - Google Patents
Medical intervention guide wire with controllable steering Download PDFInfo
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- CN112891711B CN112891711B CN202110027200.6A CN202110027200A CN112891711B CN 112891711 B CN112891711 B CN 112891711B CN 202110027200 A CN202110027200 A CN 202110027200A CN 112891711 B CN112891711 B CN 112891711B
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M25/00—Catheters; Hollow probes
- A61M25/01—Introducing, guiding, advancing, emplacing or holding catheters
- A61M25/09—Guide wires
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M25/00—Catheters; Hollow probes
- A61M25/01—Introducing, guiding, advancing, emplacing or holding catheters
- A61M25/09—Guide wires
- A61M2025/09133—Guide wires having specific material compositions or coatings; Materials with specific mechanical behaviours, e.g. stiffness, strength to transmit torque
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Abstract
The invention provides a steering-controllable medical interventional guide wire, which comprises a shape memory alloy layer and an auxiliary material layer; the guide wire is of a strip-shaped planar two-dimensional structure in a conventional state; the auxiliary material layer is attached to the surface of the shape memory alloy layer, the parts of the auxiliary material layer fixedly connected with the shape memory alloy layer are of a plurality of mutually parallel strip-shaped structures, and an included angle alpha is formed between the auxiliary material layer and the length direction of the guide wire in a conventional state; the auxiliary material layer and the shape memory alloy layer have different thermal expansion coefficients, so that when the guide wire is annealed in a vacuum high-temperature environment to train the shape memory alloy, the guide wire can be changed into a bent three-dimensional spiral tubular structure from a strip-shaped plane two-dimensional structure in a conventional state after being heated, and is memorized, and a corner theta exists between the bus direction of the three-dimensional spiral tubular structure and the length direction of the guide wire in the conventional state. The auxiliary catheter and the interventional medical device are used for assisting the catheter and other interventional medical devices to safely and effectively steer in a patient body and reach a focus, and can be safely separated from the outside of the patient body.
Description
Technical Field
The invention relates to the field of medical instruments, in particular to a steering-controllable medical intervention guide wire.
Background
Interventional medical treatment refers to a medical method in which a guide wire or a catheter is inserted into a natural duct such as a digestive tract of a patient or a blood vessel such as an artery or a vein of the patient through a tiny wound under the monitoring and guidance of an imaging device such as X-ray fluoroscopy and in-vivo radiography, and a specific interventional medical device is delivered to a lesion site of the patient to perform minimally invasive treatment. The interventional therapy has the advantages of small wound, wide adaptation diseases and few complications, can directly act on the pathological change position, greatly improves the drug concentration of the pathological change position, and can reduce the drug dosage and the drug side effects brought by the drug dosage while improving the curative effect; and the medical support can be accurately implanted into the position of pathological changes, so that the curative effect is obviously improved. Meanwhile, the invasive medical treatment has small wound, the patient is easy to recover after the operation, the hospitalization time is short, and the invasive medical treatment gradually becomes the first choice treatment means of various medical requirements such as tumor chemotherapy, thrombolysis, precise drug delivery, stent implantation and the like in recent years.
During interventional therapy, a doctor needs to control an interventional medical device to enter a patient body and go forward in complicated natural body ducts and blood vessels until reaching a focus. The commonly used surgical procedures are: firstly, medical imaging equipment such as X-ray fluoroscopy, in-vivo radiography and the like is used as a guide, a guide wire is arranged in a natural pore canal or a blood vessel of a patient after penetrating through a catheter, the guide wire is ensured to extend out of the front end of the catheter all the time, and the head of the guide wire has a certain fixed angle. Under the monitoring of digital images, a doctor advances a guide wire for a certain distance, and the guide wire is rotated at a blood vessel branch to adapt the bent head of the guide wire to enter a target branch, in the process, the guide wire with other bent shapes is required to be replaced according to the bending condition of the branch as necessary, and then the catheter is pushed to pass through the guide wire to enter the target branch. Repeating the above process until the catheter reaches the focus position, drawing out the guide wire from the patient body, and finally advancing the specific medical appliance along the catheter formed in the patient body and reaching the focus for interventional therapy.
It can be seen from the above operation process that the existing guide wire cannot controllably deflect, so that the head of the guide wire needs to be bent to have a fixed angle before entering the body of a patient, which makes the interventional medical treatment need to frequently replace the guide wire with a proper bending angle during the operation to meet various pore canals and blood vessel branches encountered in the operation process. Meanwhile, since the curved shape of the guide wire head cannot be changed, the head of the guide wire is often easy to hook the catheter port or even damage the catheter wall when the guide wire is withdrawn. These drawbacks of existing guidewires result in time and labor consuming interventional medical procedures, prolonged procedure time, increased exposure of patients and medical personnel to more X-ray radiation, high surgical risk, and a shortened effective treatment window for the patient. Therefore, the research on a controllable micro steering mechanism as a medical intervention guide wire, an auxiliary catheter and other interventional medical devices can safely and conveniently steer in natural pore canals and blood vessels of a human body and reach focuses, and has very important significance and value in safely separating from the human body.
Disclosure of Invention
The invention provides a steering-controllable medical intervention guide wire which is used for assisting a catheter and other interventional medical instruments to safely and effectively steer in a patient body and reach a focus and can safely escape from the outside of the patient body.
The technical scheme of the invention is as follows:
the steerable medical intervention guide wire comprises a biocompatible shape memory alloy layer and a biocompatible auxiliary material layer; the guide wire is of a strip-shaped planar two-dimensional structure in a conventional state; the auxiliary material layer is attached to the surface of the shape memory alloy layer, the parts of the auxiliary material layer, which are fixedly connected with the shape memory alloy layer, are of a plurality of mutually parallel strip-shaped structures, and an included angle alpha is formed between the auxiliary material layer and the length direction of the guide wire in a conventional state; the auxiliary material layer and the shape memory alloy layer have different thermal expansion coefficients of materials; the difference enables the guide wire to be annealed in a vacuum high-temperature environment to train the shape memory alloy, the guide wire can be changed into a bent three-dimensional spiral tubular structure after being heated from a strip-shaped plane two-dimensional structure in a conventional state and is memorized, and a corner theta exists between the bus direction of the three-dimensional spiral tubular structure and the length direction of the guide wire in the conventional state.
The guide wire has a planar two-dimensional structural state and a three-dimensional helical tubular structural state, and automatically changes between the two states according to temperature changes.
Furthermore, the guide wire adopts a power-on heating mode, and a layer of insulating film is coated on the outer side of the guide wire.
Further, hydrogel is adopted in the insulating film.
Further, at least one of the shape memory alloy layer and the auxiliary material layer in the guide wire is a hollow structure, and when the guide wire is in a planar two-dimensional structure state, the hollow structure is provided with a plurality of parallel thin film alloy strips forming an alpha angle with the length direction of the guide wire and is fixedly connected with the other layer through the parallel thin film alloy strips.
Further, at least one of the shape memory alloy layer and the auxiliary material layer in the guide wire is a hollow structure, when the guide wire is in a planar two-dimensional structure state, the hollow structure is provided with thin film alloy strips which are positioned at two sides in the width direction of the guide wire and along the length direction of the guide wire, and two thin film alloy strips which are perpendicular to the length direction of the guide wire, so that a rectangular outer contour of the hollow structure is formed; a plurality of parallel thin film alloy strips which form an angle alpha with the length direction of the guide wire and are connected with the outer contour at two ends are arranged in the rectangular outer contour, and the inner area of the rectangular outer contour is divided into a plurality of hollow areas; and is fixedly connected with the other layer through the film alloy strips forming the rectangular outer contour and the parallel film alloy strips.
Furthermore, a plurality of parallel thin film alloy strips which form an angle of 180-alpha degrees with the length direction of the guide wire and are connected with the outer contour at two ends are arranged in the rectangular outer contour, and the inner area of the rectangular outer contour is divided into a plurality of hollowed-out net-shaped areas; the angle of 180-alpha is formed between the parallel film alloy strip and the length direction of the guide wire, and the two ends of the parallel film alloy strip connected to the outer contour are not fixedly connected with the other layer.
Furthermore, after the guide wire is heated and then is changed into a bent three-dimensional spiral tubular structure, the diameter D of the spiral tube can be according to a formula
Adjustments were made where ω, E, T, and α represent the material width, young's modulus, thickness, and coefficient of thermal expansion, respectively, of the portion of the shape memory alloy layer that was laminated to the auxiliary material layer, subscripts 1 and 2 represent the shape memory alloy and auxiliary material, respectively, and Δ T represents the difference between the annealing temperature and the pre-annealing temperature.
Furthermore, after the guide wire is heated and changed into a bent three-dimensional spiral tubular structure, the guide wire corner theta is according to a formula
θ＝α-90°
And determining that the guide wire corner refers to an included angle between the generatrix direction of the spiral tube and the length direction of the guide wire in a planar two-dimensional state.
Further, the shape memory alloy adopts biocompatible alloy materials with shape memory function, including nickel-titanium alloy or copper-based alloy.
Further, when the driving electrode is located on the auxiliary material layer, the auxiliary material is a conductive metal material with a thermal expansion coefficient different from that of the shape memory alloy material, and the conductive metal material comprises gold, silver, platinum or aluminum.
Further, when the driving electrode is in the shape memory alloy layer, the auxiliary material is a metal material or a nonmetal material with a thermal expansion coefficient different from that of the shape memory alloy material.
Advantageous effects
The invention has the beneficial effects that: a novel safe medical intervention guide wire is provided, which is used for assisting a catheter and other interventional medical devices to navigate and turn to a focus position in a patient body. The medical intervention guide wire provided by the invention can keep the normal flow of blood in the operation process without blockage, is made of biocompatible materials, and cannot cause any harm to human bodies. Meanwhile, the provided medical intervention guide wire can automatically and rapidly change between two modes of a two-dimensional plane rectangular net shape and a three-dimensional spiral tubular shape according to temperature change, so that the guide catheter is controlled to turn in a complex vascular environment, the guide catheter can safely reach a focus position, and then the guide catheter can be restored to a plane two-dimensional shape before bending and safely separated from a human body along the guide catheter, and a catheter port cannot be hooked or the inner wall of the guide catheter cannot be damaged. The insulating film on the surface of the guide wire can prevent the guide wire from short circuit in a solution or blood environment and can reduce resistance and lubricate. The medical intervention guide wire meets the requirements of a planar preparation process, can be manufactured in large scale and in batch by an MEMS (micro-electromechanical systems) manufacturing process, and has the advantages of high manufacturing precision, low production cost and capability of reducing the cost of surgical instruments.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic view of a two-dimensional planar rectangular mesh structure of a medical interventional guide wire after manufacture according to one embodiment;
FIG. 2 is a sectional view taken along line A-A in the first embodiment;
FIG. 3 is a schematic view of a three-dimensional helical tubular structure of a medical intervention guidewire according to an embodiment of the present invention during a medium-high annealing or controlled temperature above the transformation temperature of the shape memory alloy;
FIG. 4 is a schematic view of a two-dimensional planar rectangular mesh structure of a lower aluminum film according to an embodiment;
FIG. 5 is an enlarged view of a portion of a lower aluminum film mesh structure according to an embodiment;
FIG. 6 is a schematic view of a two-dimensional planar rectangular semi-reticular structure of the upper layer of the Nitinol thin film according to an embodiment;
FIG. 7 is a partial enlarged view of a portion of the semi-reticulated structure of the nitinol film of the upper layer in the first embodiment;
FIG. 8 is a schematic view of a two-dimensional planar rectangular mesh structure of a medical interventional guide wire manufactured according to the second embodiment;
FIG. 9 is a schematic view of a three-dimensional helical tubular structure of the medical intervention guidewire according to the second embodiment when the high-temperature annealing or control temperature is higher than the transformation temperature of the shape memory alloy;
FIG. 10 is a partially enlarged view of the lower net-like structure of the shape memory alloy thin film according to the second embodiment;
FIG. 11 is a partial enlarged view of a portion of an upper aluminum film structure in accordance with a second embodiment;
FIG. 12 is a partial enlarged view of a portion of the open upper aluminum film structure in the second embodiment;
fig. 13 to 18 are schematic diagrams illustrating a method and steps of interventional therapy using the medical interventional guidewire.
In the figure: 1. a lower film layer; 11. a first drive electrode; 12. a second drive electrode; 13. the lower layer film plane rectangular net structure; 131. the lower layer film plane rectangular net structure is alloy strips along the axial direction; 132. the lower layer film plane rectangular net structure is vertical to the axial alloy strips; 133. the rectangular net structure of the lower layer film plane and the axial direction form a parallel alloy strip with a fixed included angle; 134. the rectangular net structure of the lower layer film plane forms another parallel alloy strip with a fixed included angle with the axial direction; 2. an upper film; 21. the upper layer film is an alloy strip along the axial direction; 22. the upper layer film and the axial direction form a certain fixed included angle and are combined with parallel gold strips; 3. a water condensation film; 4. a conduit; 5. an interventional medical device; 6. a blood vessel; 61. straight line segment of blood vessel; 62. an interventional medical device target vessel branch; 63. the interventional medical device is not a target vessel branch.
Detailed Description
The invention provides a medical intervention guide wire which can be steered controllably and safely separated in a human body, can assist a catheter and other interventional medical devices in natural ducts and blood vessels of the human body to be steered safely and conveniently and reach focuses, and can be separated from the human body safely.
The steering controllable medical intervention guide wire comprises a biocompatible shape memory alloy layer and a biocompatible auxiliary material layer; the guide wire is of a strip-shaped plane two-dimensional structure in a conventional state; the auxiliary material layer is attached to the surface of the shape memory alloy layer, the parts of the auxiliary material layer, which are fixedly connected with the shape memory alloy layer, are of a plurality of mutually parallel strip-shaped structures, and an included angle alpha is formed between the auxiliary material layer and the length direction of the guide wire in a conventional state; the auxiliary material layer and the shape memory alloy layer have different thermal expansion coefficients of materials, the difference enables the guide wire to be changed into a bent three-dimensional spiral tubular structure after being heated from a strip-shaped plane two-dimensional structure in a conventional state and to be memorized when the guide wire is annealed in a vacuum high-temperature environment to train the shape memory alloy, and a corner theta exists between the bus direction of the three-dimensional spiral tubular structure and the length direction of the guide wire in the conventional state.
The guide wire has a planar two-dimensional structural state and a three-dimensional helical tubular structural state, and automatically changes between the two states according to temperature changes.
After the medical intervention guide wire is manufactured, annealing is firstly carried out in a vacuum high-temperature environment to train the shape memory alloy, at the moment, because the thermal expansion coefficients of the shape memory alloy and the auxiliary material are different, and the parts of the auxiliary material layer fixedly connected with the shape memory alloy layer are a plurality of strip-shaped structures which are parallel to each other and have an included angle alpha with the length direction of the guide wire in a conventional state, the residual thermal stress enables the guide wire to automatically bend and deform upwards in the length direction and the inner side of the hollow structure and to be coupled to show spiral deformation, and the formed spiral tubular structure forms a certain included angle with the original length direction of the guide wire. Under high temperature annealing, the shape memory alloy is in the austenite phase and can memorize the current three-dimensional helical tubular structure.
When the guide wire adopts a power-on heating mode, the outer side of the guide wire is coated with a layer of insulating film; the insulating film is preferably hydrogel.
The interventional guide wire with different spiral pipe diameters is selected according to different diameters of natural ducts and blood vessels of a human body, the interventional guide wire is of a three-dimensional spiral tubular structure which is annealed, deformed and memorized, and the relation between the diameter of a spiral pipe and material parameters and structural design parameters can be determined according to the following formula:
wherein D is the diameter of the three-dimensional spiral tube formed after the inserted guide wire is deformed, omega, E, T and alpha respectively represent the material width, Young modulus, thickness and thermal expansion coefficient of the joint section of the shape memory alloy layer and the auxiliary material layer, subscripts 1 and 2 respectively represent the shape memory alloy and the auxiliary material, and delta T represents the difference between the annealing temperature and the temperature before annealing.
According to different natural body pore canals and blood vessel branch angles encountered in interventional medical treatment, interventional guide wires with different deflection bending angles are selected. The included angle between the bus direction of the three-dimensional spiral pipe formed after the guide wire is deformed and the original length direction depends on the structural angle between the direction of the fixed connecting section of the shape memory alloy and the auxiliary material in the structure and the length direction of the guide wire in a two-dimensional state. According to the ABAQUS finite element statics simulation result, when the structure angle is changed between 0 degree and 180 degrees, the rotation angle between the generatrix direction of the formed three-dimensional spiral pipe and the original length direction is changed between-90 degrees and 90 degrees. The material parameters and finite element simulation conditions are shown in table 1:
TABLE 1
By adopting the material parameters, the guide wire is firstly modeled in SolidWorks, then is guided into ABAQUS for material attribute endowment, grid division and other preprocessing, then the guide wire is applied with the solid support boundary condition of the driving electrode, and the predefined temperature field variation amplitude is set to be 500 ℃. According to the finite element statics simulation method, typical results of conducting simulation on guide wire rotation angles theta under different structural angles are shown in table 2, wherein theta takes the length direction of the guide wire in a two-dimensional state as reference 0 degree, and when viewed from the top, the theta is deflected to the left to be positive, and the theta is deflected to the right to be negative.
TABLE 2
It can be derived that the relationship between the guide wire turns and the structure angle is:
θ＝α-90° (2)
according to the size of the inner diameter of a natural pore canal or a blood vessel of a human body and a branch angle in interventional medical treatment, an interventional guide wire with appropriate material matching, size and structural parameters is selected according to the formula (1), the finite element simulation method and the formula (2).
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
Example 1:
as shown in fig. 1, the medical intervention guide wire is a two-dimensional planar rectangular mesh structure after being manufactured. The guide wire is composed of two layers of biocompatible film materials and an insulating film.
In this example, the lower film 1 is made of aluminum, the upper film 2 is made of nickel-titanium alloy, and the insulating film 3 is made of hydrogel.
As shown in fig. 1, the lower aluminum film can be functionally divided into a first driving electrode 11, a second driving electrode 12 and a mesh structure 13, and is integrally formed. As shown in fig. 2, the insulating film hydrogel 3 is uniformly coated on the outer surface of the interventional guide wire. As shown in fig. 3, during high temperature annealing of the medical intervention guide wire, due to thermal stress generated by mismatch of thermal expansion coefficients of the fixed connection part between the lower film 1 and the upper film 2, the upper film is automatically deformed into a three-dimensional spiral tubular structure, and forms an off angle with the original axis, and the upper shape memory alloy film can memorize the current three-dimensional shape. After the annealing is finished, voltage is applied to the first driving electrode 11 and the second driving electrode 12 by utilizing Joule effect, so that the overall temperature of the guide wire is raised, when the temperature exceeds the phase transition temperature of the shape memory alloy film, the shape memory function of the upper layer shape memory alloy film is triggered, the shape memory alloy is transformed from a martensite phase to an austenite phase, the Young modulus is increased, and the shape memory function leads the guide wire to be automatically deformed and kept into a previously memorized three-dimensional spiral tubular structure and generate an oblique angle with the original axial direction; after the steering is completed, the voltage on the first driving electrode 11 and the second driving electrode 12 is cut off, so that the overall temperature of the guide wire is reduced, when the temperature is lower than the phase transition temperature of the shape memory alloy, the shape memory function of the upper layer shape memory alloy film disappears, the austenite phase is converted into the martensite phase, the Young modulus is reduced, at the moment, the restoring stress of the lower layer film 1 can lead the guide wire to restore to a two-dimensional plane rectangular net structure, and the orientation of the guide wire is restored to the axial direction.
Fig. 4 is a schematic diagram of a two-dimensional planar hollow-out mesh structure of a lower aluminum film, wherein the two axial thin film alloy strips 131 and the two vertical thin film alloy strips 132 form a rectangular outer contour of the guide wire. Within the rectangular profile, the web 13 is formed by parallel thin film alloy strips 133 and 134 having respective angles of 45 ° and 135 ° with respect to the axial direction. Wherein the width of each film alloy strip is 10 micrometers, the thickness is 0.5 micrometer, the side length of the hollow square meshes in the net structure is 100 micrometers, and the side length of the right angles of the meshes of the right-angle triangle is 100 micrometers. FIG. 5 is a partial enlarged view of the lower aluminum film network.
Fig. 6 is a schematic view of a two-dimensional planar hollow semi-mesh structure of an upper layer of nitinol film, wherein two parallel alloy strips 21 along the axial direction of the guide wire and a plurality of parallel thin film alloy strips 22 uniformly distributed therebetween are plated at corresponding positions of a lower layer of aluminum film mesh structure, which together form the medical intervention guide wire in this embodiment. Fig. 7 is a partial enlarged view of a two-dimensional planar hollow semi-reticular structure of an upper layer of a nickel-titanium alloy film, wherein the hollow semi-reticular structure 2 is formed by two film alloy strips 21 along the axial direction and a plurality of parallel film alloy strips 22 which are uniformly distributed and form an included angle of 45 degrees with the axial direction. Wherein the width of each film alloy strip is 8 microns, the thickness is 0.3 micron, and the vertical distance between two long sides of the hollow parallelogram in the semi-reticular structure is 100 microns. The nickel-titanium alloy film is plated on the specific position of the aluminum film, so that the distance between the outline of the nickel-titanium alloy film and the corresponding outline of the aluminum film is 1 micron, specifically, the width of the nickel-titanium alloy strip is 8 microns, the width of the alloy strip of the lower layer of aluminum is 10 microns, and the distance between the boundary of the nickel-titanium alloy strip and the boundary of the aluminum alloy strip is 1 micron in a top view, which is provided based on the convenient design angle of MEMS; of course, if other designs or processing means are used, the width of the upper layer gold bar and the lower layer can be equal to each other, and are 10 micrometers.
The lower layer auxiliary material in this embodiment is not limited to the aluminum film material, and other conductive thin film materials with biocompatibility, such as gold, silver, platinum, and the like, and the thermal expansion coefficient of which is not equal to that of the upper layer shape memory alloy may also be used. The upper shape memory alloy material in this embodiment is not limited to nickel-titanium alloy, and other alloy materials having a shape memory function, such as nickel-titanium base and copper base, may be used. In the embodiment, included angles between a plurality of parallel thin film alloy strips in the rectangular outline of the aluminum film and the axial alloy strips are not limited to 135 degrees and 45 degrees, and can be any angle within 0-180 degrees; the included angles between a plurality of parallel thin film alloy strips and axial alloy strips in the nickel-titanium alloy thin film can be selected to be jointed with the alloy strips in a certain direction of the aluminum film layer. The thickness of each layer of film, the width of the alloy strips and the distance between the alloy strips can be adjusted according to the diameter of the applied human body duct or blood vessel and the branch angle according to the formula (1), the formula (2) and the finite element simulation method.
Example 2:
as shown in fig. 8, the medical intervention guide wire is manufactured into a two-dimensional planar rectangular mesh structure. The guide wire is composed of two layers of biocompatible thin film materials and an insulating thin film, wherein in the example, the lower thin film 1 is made of nickel-titanium alloy, the upper thin film 2 is made of aluminum, and the insulating thin film 3 is made of hydrogel. As shown in fig. 8, the lower shape memory alloy thin film 1 can be functionally divided into a first driving electrode 11, a second driving electrode 12, and a mesh structure 13, and integrally formed. The insulating film hydrogel 3 is uniformly coated on all the outer surfaces of the interventional guide wire. As shown in fig. 9, during high temperature annealing of the medical intervention guide wire, due to the thermal stress generated by the mismatch of the thermal expansion coefficients of the fixed connection part between the lower film 1 and the upper film 2, the lower film is automatically deformed into a three-dimensional spiral tubular structure, and a corner is generated with the original axial direction, so that the lower shape memory alloy film can memorize the current three-dimensional shape. After the annealing is finished, voltage can be applied to the first driving electrode 11 and the second driving electrode 12 by Joule effect, so that the overall temperature of the guide wire is raised, when the temperature exceeds the phase transition temperature of the shape memory alloy film, the shape memory function of the lower layer shape memory alloy film is triggered, the shape memory alloy is transformed from a martensite phase to an austenite phase, the Young modulus is increased, and the shape memory function leads the guide wire to be automatically deformed and to be kept into the previously memorized three-dimensional spiral tubular structure and generate an oblique angle with the original axial direction; after the steering is finished, the voltage on the first driving electrode 11 and the second driving electrode 12 is cut off, so that the overall temperature of the guide wire is reduced, when the temperature is lower than the phase transition temperature of the shape memory alloy, the shape memory function of the lower-layer shape memory alloy film disappears, the austenite phase is converted into the martensite phase, the Young modulus is reduced, at the moment, the restoring stress of the upper-layer film 2 can lead the guide wire to restore to a two-dimensional plane rectangular net structure, and the orientation of the guide wire is restored to the axial direction.
Fig. 10 is a schematic diagram of a two-dimensional planar network structure of a lower shape memory alloy film, which includes two axial film alloy strips 131 and two vertical film alloy strips 132 that form a rectangular outer profile of the guide wire. Within the rectangular profile, the mesh structure 13 is formed by parallel thin film alloy strips 133 and 134 which respectively form an angle of 63 degrees and an angle of 153 degrees with the axial direction. Wherein the width of each film alloy strip is 10 micrometers, the thickness is 0.5 micrometer, the side length of the hollow square meshes in the net structure is 100 micrometers, and the side length of the right angles of the meshes of the right-angle triangle is 100 micrometers.
Fig. 11 is a schematic diagram of a two-dimensional planar semi-network structure of an upper aluminum film, in which two parallel alloy strips 21 along the axial direction of the guide wire and a plurality of parallel thin-film alloy strips 22 uniformly distributed therebetween are plated at corresponding positions of a lower shape memory alloy thin-film network structure portion, so as to form the medical intervention guide wire in this embodiment. Of course, an open top film structure may be formed from a plurality of uniformly distributed parallel thin film alloy strips 22 oriented at 63 ° to the axial direction as shown in fig. 12. Wherein each thin film alloy strip has a width of 8 microns and a thickness of 0.3 microns. The specific position of the aluminum film plated on the nickel-titanium alloy film is that the distance between the outline of the aluminum film and each corresponding outline of the nickel-titanium alloy film is 1 micron.
The upper layer auxiliary material in this embodiment is not limited to the aluminum film material, and may be a conductive film material having biocompatibility, such as gold, silver, platinum, or the like, and having a thermal expansion coefficient not equal to that of the lower layer shape memory alloy, or may be an insulating film material having biocompatibility, such as silicon, silicon dioxide, or the like, and having a thermal expansion coefficient not equal to that of the lower layer shape memory alloy. The lower-layer shape memory alloy material in this embodiment is not limited to nickel-titanium alloy, and other alloy materials having a shape memory function, such as nickel-titanium base and copper base, may be used. In the embodiment, included angles between a plurality of parallel film alloy strips in the rectangular outline of the shape memory alloy film and the axial alloy strips are not limited to 63 degrees and 153 degrees, and can be any angle within 0-180 degrees; several parallel thin film alloy strips of the aluminum film can be selectively jointed with alloy strips of the shape memory alloy layer in a certain direction. The thickness of each layer of film, the width of the alloy strips and the distance between the alloy strips can be adjusted according to the diameter of the applied human body pore canal or blood vessel and the branch angle according to the formula (1), the formula (2) and the finite element simulation method.
The medical intervention guide wire is a flat two-dimensional structure at room temperature. When the guide wire is used for interventional medical operation, the catheter passes through the guide wire and then enters the blood vessel, and the guide wire extends out of the front end of the catheter all the time. When a natural pore canal or a blood vessel branch needing to be steered is met, the Joule effect is utilized, for example, voltage is applied to a driving electrode of a medical intervention guide wire, the overall temperature of the guide wire is raised, when the temperature exceeds the phase transition temperature of the shape memory alloy (the temperature can be manually controlled by adjusting the components of the shape memory alloy and is slightly higher than the normal temperature in a human body), the shape memory function of the shape memory alloy is triggered, the shape memory alloy is transformed from a martensite phase to an austenite phase, the Young modulus is increased, the guide wire is hardened, and the shape memory function leads the guide wire to be automatically deformed, maintain the three-dimensional spiral tubular structure memorized before and generate bending, so that a steering passage is formed for the catheter, and the steering is forced to be steered and the inner wall of the blood vessel is protected. After the steering is finished, the voltage of a driving electrode of the medical intervention guide wire is cut off, the temperature of the guide wire can be automatically reduced along with the flowing of blood, when the temperature is lower than the phase transition temperature of the shape memory alloy, the shape memory function of the shape memory alloy disappears, the austenite phase is converted into the martensite phase, the Young modulus is reduced, the guide wire is softened, the restoring stress of the auxiliary material can guide the guide wire to be restored to a two-dimensional plane structure, the orientation of the guide wire is restored to the axial direction, and the guide wire and the catheter are jointly straight in the blood vessel until the next branch bending part. The control process is repeated until the catheter reaches the focus, the voltage of the guide wire driving electrode is cut off, the guide wire driving electrode is enabled to be restored to a two-dimensional plane structure, the orientation is restored to the axial direction, the guide wire can be smoothly and safely separated from a human body along the catheter at the moment, and the guide wire is different from the traditional guide wire which is easy to hook a catheter port or injure the inner wall of the catheter when being separated from the human body due to the fact that the bending state cannot be changed.
In the process, the hollow mesh structure of the interventional guide wire ensures that blood normally circulates without blockage, the hydraulic film on the surface of the interventional guide wire ensures that the guide wire is insulated in human body solution and blood environments, short circuit is prevented, and meanwhile, the hydraulic film greatly reduces the friction force between the surface of the guide wire and human body ducts, blood vessels and the inner wall of the guide tube, so that the guide wire is convenient to move. Finally, the specific interventional medical appliance is sent to the focus along the catheter which is formed in the human body for interventional medical treatment. In conclusion, the steering controllable medical intervention guide wire can assist a catheter and other interventional medical devices to safely steer in a vascular complex environment to directly reach a focus and then safely separate from the body.
Fig. 13-18 are schematic diagrams illustrating a method and steps for performing an interventional procedure using the medical interventional guide wire according to the first embodiment.
As shown in fig. 13, the medical interventional guidewire and catheter 4 of the illustrated embodiment are co-deployed within a patient's vessel 6, securing the guidewire at the forward end of the catheter port. The blood vessel 6 is formed into a Y-shaped path by a straight line segment 61, an interventional medical device target vessel branch 62 and an interventional medical device non-target vessel branch 63. As shown in fig. 14, when advancing the medical intervention guide wire in a two-dimensional planar state together with catheter 4 in straight section 61 of the blood vessel to reach branches 62 and 63, the guide wire is first rotated at a suitable angle along the axis of the medical intervention guide wire where first drive electrode 11 and second drive electrode 12 are located. As shown in fig. 15, a voltage is applied to the first driving electrode 11 and the second driving electrode 12 simultaneously, so that the guide wire is electrified and heated, and after the temperature is higher than the phase transition temperature of the shape memory alloy, the upper layer nitinol film 2 will cause the guide wire to be rapidly transformed into a three-dimensional spiral tubular structure and form a certain included angle in the original axial direction. As shown in fig. 16, the young's modulus increases due to the austenitic phase of the guidewire, the guidewire becomes stiffer, and the catheter 4 is deflected along the guidewire and into the target vessel branch 62 as the catheter 4 is advanced further over the medical guidewire. In this process, the mesh-like guidewire can ensure blood circulation without obstruction. As shown in fig. 17, after all the steering is completed, the voltage of the first driving electrode 11 and the second driving electrode 12 is cut off, the temperature of the guide wire is rapidly reduced to be lower than the phase transition temperature due to the heat dissipation of the blood flow, the lower aluminum film layer 1 can promote the structure to be restored to a planar two-dimensional reticular structure, at the moment, the guide wire is in a martensite phase, the young modulus is reduced, the guide wire is softened, and the orientation is restored to the original axial linear direction, so that the guide wire can be safely and smoothly withdrawn to the outside of the patient along the catheter without damaging the inner wall of the catheter. In the whole process, the insulation film on the surface of the medical intervention guide wire can prevent the guide wire from short circuit in a solution or blood environment and can reduce resistance and lubricate. As shown in fig. 18, the specific interventional medical device 5 is finally guided along the catheter that has been formed in the patient to the lesion for interventional medical treatment.
The medical scene of the embodiment is blood vessel interventional medical treatment, and can also be applied to other non-blood vessel natural pore canals of human intestinal tracts, respiratory tracts and the like.
In conclusion, the steering controllable medical intervention guide wire provided by the invention well solves the problems that the navigation catheter in the existing interventional medical treatment is high in steering difficulty and enters a focus, the guide wire is not easy to separate from a human body, the risk coefficient is large, the time is long, complications are easy to cause and the like, provides a novel, safe and easy and convenient steering controllable medical intervention guide wire for a doctor in an interventional medical operation, and greatly reduces the risk and pain of a patient in accepting the operation. Meanwhile, the design scheme of the medical intervention guide wire meets the requirement of the MEMS two-dimensional plane preparation process, so that the large-scale batch manufacturing can be carried out through the MEMS manufacturing process, the manufacturing precision is high, the production cost is low, the price of a finished product can be greatly reduced while the quality of the guide wire is ensured, and the cost of the operation is reduced.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention.
Claims (9)
1. A steerable medical intervention guidewire, comprising: comprises a shape memory alloy layer with biocompatibility and an auxiliary material layer with biocompatibility; the guide wire is of a strip-shaped planar two-dimensional structure in a conventional state; the auxiliary material layer is attached to the surface of the shape memory alloy layer, the parts of the auxiliary material layer, which are fixedly connected with the shape memory alloy layer, are of a plurality of mutually parallel strip-shaped structures, and an included angle alpha is formed between the auxiliary material layer and the length direction of the guide wire in a conventional state; the auxiliary material layer and the shape memory alloy layer have different thermal expansion coefficients of materials; the difference enables the guide wire to be annealed in a vacuum high-temperature environment to train the shape memory alloy, the guide wire can be changed into a bent three-dimensional spiral tubular structure after being heated from a strip-shaped plane two-dimensional structure in a conventional state and is memorized, and a corner theta exists between the bus direction of the three-dimensional spiral tubular structure and the length direction of the guide wire in the conventional state; the guide wire has a planar two-dimensional structural state and a three-dimensional spiral tubular structural state, and automatically changes between the two states according to temperature change; when the driving electrode is positioned on the auxiliary material layer, the auxiliary material is made of conductive metal material with a thermal expansion coefficient different from that of the shape memory alloy material, and the conductive metal material comprises gold, silver, platinum or aluminum; when the driving electrode is positioned in the shape memory alloy layer, the auxiliary material is a metal material or a nonmetal material with a thermal expansion coefficient different from that of the shape memory alloy material.
2. The steerable medical intervention guidewire of claim 1, wherein: the guide wire adopts a power-on heating mode, and a layer of insulating film is coated on the outer side of the guide wire.
3. The steerable medical intervention guidewire of claim 2, wherein: the insulating film adopts hydrogel.
4. The steerable medical intervention guidewire of claim 1, wherein: at least one of the shape memory alloy layer and the auxiliary material layer in the guide wire is a hollow structure, and when the guide wire is in a planar two-dimensional structure state, the hollow structure is provided with a plurality of parallel thin film alloy strips forming an alpha angle with the length direction of the guide wire and is fixedly connected with the other layer through the parallel thin film alloy strips.
5. The steerable medical intervention guidewire of claim 1, wherein: at least one of the shape memory alloy layer and the auxiliary material layer in the guide wire is a hollow structure, and when the guide wire is in a planar two-dimensional structure state, the hollow structure is provided with thin film alloy strips which are positioned at two sides in the width direction of the guide wire and along the length direction of the guide wire, and two thin film alloy strips which are vertical to the length direction of the guide wire, so that a rectangular outer contour of the hollow structure is formed; a plurality of parallel thin film alloy strips which form an angle alpha with the length direction of the guide wire and are connected with the outer contour at two ends are arranged in the rectangular outer contour, and the inner area of the rectangular outer contour is divided into a plurality of hollow areas; and is fixedly connected with the other layer through the film alloy strips forming the rectangular outer contour and the parallel film alloy strips.
6. The steerable medical intervention guidewire of claim 5, wherein: the rectangular outer contour is internally provided with a plurality of parallel thin film alloy strips which form an angle of 180-alpha degrees with the length direction of the guide wire and are connected with the outer contour at two ends, and the inner area of the rectangular outer contour is divided into a plurality of hollowed-out net-shaped areas together; the angle of 180 degrees to alpha degrees is formed between the two parallel thin film alloy strips and the length direction of the guide wire, and the two ends of the parallel thin film alloy strips are connected to the outer contour and are not fixedly connected with the other layer.
7. The steerable medical intervention guidewire of claim 1, wherein: after the guide wire is heated to be changed into a bent three-dimensional spiral tubular structure, the diameter D of the spiral tube can be adjusted according to a formula, wherein omega, E, T and alpha respectively represent the material width, Young modulus, thickness and thermal expansion coefficient of a joint part of the shape memory alloy layer and the auxiliary material layer, subscripts 1 and 2 respectively represent the shape memory alloy and the auxiliary material, and delta T represents the difference between the annealing temperature and the temperature before annealing.
8. The steerable medical intervention guidewire of claim 1, wherein: after the guide wire is heated and changed into a bent three-dimensional spiral tubular structure, a guide wire corner theta is determined according to a formula theta of alpha-90 degrees, and the guide wire corner theta refers to an included angle between the generatrix direction of the spiral tube and the length direction of the guide wire in a planar two-dimensional state.
9. The steerable medical intervention guidewire of claim 1, wherein: the shape memory alloy adopts biocompatible alloy materials with shape memory function, including nickel-titanium alloy or copper-based alloy.
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| CN113977593B (en) * | 2021-09-26 | 2023-03-31 | 浙江大学 | Driving mechanism for robot frogman, humanoid mechanical arm and stepless bending and twisting |
| CN115363507A (en) * | 2022-06-15 | 2022-11-22 | 湖南省华芯医疗器械有限公司 | Endoscope instrument tube, insertion part with expandable distal end, handle and endoscope |
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