A medical absorbable thoracic aortic stent system

Abstract

The invention relates to the field of medical devices, and specifically discloses a medical absorbable thoracic aorta stent system, comprising a stent unit and an expansion device; the stent unit comprises an upper deformation ring, a lower deformation ring and a first connecting rib; the upper deformation ring is composed of a plurality of upper deformation blocks connected in sequence along the circumferential direction to form a wavy annular structure, and the lower deformation ring is composed of a plurality of lower deformation blocks connected in sequence along the circumferential direction to form a wavy annular structure; the expansion device comprises an operating balloon and an inflation device, the operating balloon is used to extend into the stent unit and be inflated and expanded by the inflation device; the stent unit also comprises a plurality of upper limit ribs and lower limit ribs arranged along its axial direction, the upper end of the upper limit rib is fixedly connected to the bottom of the wave crest of the upper deformation ring, and the lower end of the lower limit rib is fixedly connected to the top of the wave trough of the corresponding lower deformation ring.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, and in particular to a medical absorbable thoracic aorta stent system. Background Art

[0002] Absorbable vascular stents are also called degradable vascular stents. Due to their excellent flexibility, biocompatibility, moderate degradability and mechanical support, they have become a very promising treatment for coronary artery stenosis. In addition, they can slowly degrade into safe and non-toxic small molecules while the blood vessels are repaired and healed, and are excreted from the body along with metabolic wastes. They have the potential to solve the long-term restenosis problem after permanent metal stent implantation. The materials of absorbable aortic stents are mostly high molecular polymers, including polyurethane, polylactic acid, polyglycolide, polylactide, polydioxanone, polycaprolactone, etc. These materials gradually degrade in the body and are excreted from the body after participating in the body's metabolism.

[0003] Existing absorbable vascular stents and vascular stent systems can expand the absorbable vascular stent through balloon operation as shown in patent CN112399832 A (absorbable intravascular device that shortens during expansion to create space for vascular movement).

[0004] In cardiac surgery, emergency surgery when early aortic dissection causes multi-organ malperfusion is extremely risky and has a very high mortality rate. The best way is to open the true lumen, temporarily restore blood supply to the organs, and then perform surgery after the organ function is restored. The currently used interventional covered stents are difficult to remove during surgery and have extremely high surgical complications. Using a medical absorbable thoracic aortic stent is a better way, but the existing medical absorbable thoracic aortic stent does not have the ability to self-expand, and its expansion force is insufficient to fully expand the true lumen. Even if it is expanded by a balloon, it will gradually shrink after the balloon is detached.

[0005] Therefore, in order to solve the above problems, a medical absorbable thoracic aortic stent system with sufficient expansion force is needed. Summary of the invention

[0006] In view of this, an object of the present invention is to provide a medical thoracic aortic stent system with sufficient expansion force.

[0007] To achieve the above-mentioned purpose, the present invention provides a medical absorbable thoracic aorta stent system, comprising a stent unit made of absorbable material and an expansion device for expanding the stent unit; the stent unit comprises an upper deformation ring, a lower deformation ring arranged below the upper deformation ring, and a plurality of first connecting ribs for axially connecting the upper deformation ring and the lower deformation ring; the upper deformation ring is composed of a plurality of upper deformation blocks connected in sequence along the circumferential direction to form a wavy annular structure, the lower deformation ring is composed of a plurality of lower deformation blocks connected in sequence along the circumferential direction to form a wavy annular structure, and the upper deformation blocks and the lower deformation blocks are arranged in a manner of staggered crests and troughs, the upper end of the first connecting rib is fixedly connected to the bottom of the trough of the upper deformation ring, and the lower end is fixedly connected to the top of the crest of the corresponding lower deformation ring;

[0008] The expansion device comprises an operating balloon and an inflation device, wherein the operating balloon is used to extend into the stent unit and to be inflated and expanded by the inflation device;

[0009] The bracket unit also includes a plurality of upper limit ribs and lower limit ribs arranged along its axial direction, the upper end of the upper limit rib is fixedly connected to the bottom of the wave crest of the upper deformation ring, and the lower end of the lower limit rib is fixedly connected to the top of the wave trough of the corresponding lower deformation ring; when the upper deformation ring and the lower deformation ring expand synchronously under the action of the operating balloon and cause the bracket unit to expand and shorten, the upper limit rib and the corresponding lower limit rib are locked with each other through the locking structure and prevent the bracket unit from retracting.

[0010] As a further improvement to the technical solution of the present invention, when the upper deformation ring and the lower deformation ring expand asynchronously to a set state under the action of the operating balloon, the locking structure between the upper limit rib and the corresponding lower limit rib is released and the restriction on the retraction of the bracket unit is released.

[0011] As a further improvement to the technical solution of the present invention, there is a gap between the upper limit rib and the corresponding lower limit rib; the locking structure includes a locking block and a plurality of locking grooves for the locking block to be inserted into; a locking block is protruding from one side of the lower limit rib, and a plurality of blocks are protruding from the side of the upper limit rib opposite to the lower limit rib, and a locking groove is formed between adjacent blocks; when the upper deformation ring and the lower deformation ring expand synchronously under the action of the operating balloon and cause the bracket unit to expand and shorten, the locking block moves and crosses the block into the locking groove; when the upper deformation ring and the lower deformation ring expand asynchronously under the action of the operating balloon, the upper limit rib and the lower limit rib gradually move away from each other and cause the locking block to escape from the locking groove.

[0012] As a further improvement to the technical solution of the present invention, the blocks on the same lower limit rib are evenly distributed along the length direction of the lower limit rib, the block is wedge-shaped and its inclined surface is set downward, and the locking block is provided with an arc surface on the side facing the inclined surface of the block.

[0013] As a further improvement to the technical solution of the present invention, the upper limit rib and the corresponding lower limit rib are both in the shape of a straight plate or a straight rod.

[0014] As a further improvement to the technical solution of the present invention, the upper limit rib is located outside the corresponding lower limit rib.

[0015] As a further improvement of the technical solution of the present invention, the operating balloon includes a first balloon body for driving the upper deformable ring to expand and a second balloon body for driving the lower deformable ring to expand, and the bottom of the first balloon body and the top of the second balloon body are connected by a first connecting tube; the inflation device includes a first inflator and a second inflator, the first balloon body is connected to the air supply end of the first inflator through a first ventilation tube, and the second balloon body is connected to the air supply end of the second inflator through a second ventilation tube, and the first ventilation tube and the second ventilation tube are independently arranged.

[0016] As a further improvement to the technical solution of the present invention, the expansion device also includes a first pressure sensor connected to the first ventilation tube for detecting the internal pressure of the first balloon and a second pressure sensor connected to the second ventilation tube for detecting the internal pressure of the second balloon.

[0017] As a further improvement to the technical solution of the present invention, the medical thoracic aorta stent system comprises two or more stent units, and the upper and lower adjacent stent units are connected by a second connecting rib;

[0018] The number of the operating balloons is the same as the number of the bracket units; in two adjacent operating balloons, the second balloon body of the previous operating balloon is connected to the first balloon body of the next operating balloon through a second connecting tube; the first balloon bodies are connected through the first connecting tube, and the second balloon bodies are connected through the second connecting tube.

[0019] As a further improvement to the technical solution of the present invention, the first balloon body and the second balloon body have the same shape and are both elliptical, gyro-shaped or frustum-shaped.

[0020] Compared with the prior art, the present invention has the following beneficial technical effects:

[0021] The present invention provides a medical absorbable thoracic aortic stent system. When an upper deformation ring and a lower deformation ring are synchronously expanded under the action of an operating balloon, an upper limit rib and a corresponding lower limit rib maintain a specific matching relationship. When the stent unit is expanded and shortened, the upper limit rib and the corresponding lower limit rib are continuously approached, the overlap degree of the two gradually increases, and finally they are locked together through a locking structure. This locking is unidirectional, so that even if the external force disappears, the stent unit cannot retract, thereby ensuring that the thoracic aortic stent has sufficient expansion force.

[0022] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their description are used to explain the present invention but do not constitute a limitation of the present invention.

[0024] Figure 1 This is a schematic structural diagram of a medical absorbable thoracic aortic stent system in Embodiment 1 of the present invention;

[0025] Figure 2 It is a structural expansion diagram of the bracket unit in the first embodiment of the present invention;

[0026] Figure 3 for Figure 2 Middle A-direction view;

[0027] Figure 4 This is a schematic diagram of the structure of the operating balloon in the first embodiment of the present invention;

[0028] Figure 5 This is a schematic structural diagram of a medical absorbable thoracic aortic stent system in Embodiment 2 of the present invention;

[0029] Figure 6 It is a structural expansion diagram of the bracket unit in the second embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments; of course, the accompanying drawings are simplified schematic diagrams, and their proportional sizes do not constitute a limitation on the patented product.

[0031] Embodiment 1

[0032] like Figures 1 to 4 As shown: This embodiment provides a medical absorbable thoracic aorta stent system, which includes a stent unit 1 made of absorbable material and an expansion device for expanding the stent unit 1.

[0033] The bracket unit 1 includes an upper deformable ring 101, a lower deformable ring 102 arranged below the upper deformable ring 101, and a plurality of first connecting ribs 103 for axially connecting the upper deformable ring 101 and the lower deformable ring 102; the upper deformable ring 101 is connected in sequence along the circumferential direction by a plurality of upper deformable blocks 104 to form a wavy annular structure, the lower deformable ring 102 is connected in sequence along the circumferential direction by a plurality of lower deformable blocks 105 to form a wavy annular structure, and the upper deformable blocks 104 and the lower deformable blocks 105 are arranged in a manner of staggered crests and troughs, the upper end of the first connecting rib 103 is fixedly connected to the bottom of the trough of the upper deformable ring 101, and the lower end is fixedly connected to the top of the crest of the corresponding lower deformable ring 102.

[0034] "Up" and "Down" Figure 1 Directions shown shall prevail.

[0035] The stent unit 1 is made of absorbable material (i.e., biodegradable material), such as polyurethane, polylactic acid, polyglycolide, polylactide, polydioxanone, polycaprolactone, etc. The stent unit 1 has the function of expanding and supporting blood vessels. After fully exerting its function, the stent unit 1 can gradually degrade in the patient's body and eventually degrade into non-toxic products (such as water and carbon dioxide) that can be absorbed by the human body, so that the blood vessels can return to their natural state after the stent disappears.

[0036] The stent unit 1 is a basic unit for forming a vascular stent, and a single stent unit 1 can also be used as a medical device for dilating blood vessels. The upper deformation ring 101 and the lower deformation ring 102 are connected by the first connecting rib 103 to form the stent unit 1; the upper deformation block 104 and the lower deformation block 105 have the same structure, and can be in a "V" shape (including an "inverted V" shape), or can also be in a "U" shape (including an "inverted U" shape); the number of upper deformation blocks 104 in the upper deformation ring 101 and the number of lower deformation blocks 105 in the lower deformation ring 102 can be determined according to needs, and are not limited here. The upper deformation block 104 and the lower deformation block 105 are arranged in a staggered manner, that is, the crest of the upper deformation block 104 is opposite to the trough of the corresponding lower deformation block 105, and the trough of the upper deformation block 104 is opposite to the crest of the corresponding lower deformation block 105, that is, the upper deformation block 104 and the corresponding lower deformation block 105 are symmetrical based on the transverse midline of the stent unit 1. The first connecting ribs 103 may be in the shape of a straight plate, a straight rod, or a curved plate or a curved rod. In one bracket unit 1 , the number of the first connecting ribs 103 is the same as the number of the upper deformation blocks 104 and the lower deformation blocks 105 .

[0037] The upper deformation block 104 and the lower deformation block 105 can expand outward and stretch and shorten when subjected to radial force, so that the upper deformation ring 101 and the lower deformation ring 102 can also expand outward and stretch and shorten. At this time, the stent unit 1 as a whole also expands and shortens; when the radial force disappears, the stent unit 1 gradually compresses and stretches or even returns to its original state, which is the retraction of the stent unit 1; it is precisely because of the existence of the retraction effect that the expansion force of the existing vascular stent is insufficient.

[0038] The expansion device includes an operating balloon 2 and an inflation device, wherein the operating balloon 2 is used to extend into the stent unit and be inflated by the inflation device. The radial force exerted on the upper deformation block 104 and the lower deformation block 105 is provided by the operating balloon 2, and the inflation device can be used for the inflation and deflation operations of the operating balloon 2. As one example, the operating balloon 2 can adopt the balloon shown in patent CN112399832 A, for example. The inflation device can adopt an existing air pump. In the preparatory stage of the operation, the stent unit 1 can be sleeved outside the operating balloon 2, and the stent unit 1 and the operating balloon 2 are delivered into the human thoracic aorta together during the operation.

[0039] The present embodiment provides a medical absorbable thoracic aorta stent system, the main improvement of which is that the stent unit 1 also includes a plurality of upper limit ribs 106 and lower limit ribs 107 arranged along its axial direction, the upper end of the upper limit rib 106 is fixedly connected to the bottom of the wave crest of the upper deformable ring 101, and the lower end of the lower limit rib 107 is fixedly connected to the top of the wave trough of the corresponding lower deformable ring 102; when the upper deformable ring 101 and the lower deformable ring 102 expand synchronously under the action of the operating balloon 2 and cause the stent unit 1 to expand and shorten, the upper limit rib 106 and the corresponding lower limit rib 107 are locked with each other through the locking structure and prevent the stent unit 1 from retracting.

[0040] The upper limit rib 106 and the lower limit rib 107 are arranged in the area formed by the upper deformation block 104, the corresponding lower deformation block 105 and the two adjacent first connecting ribs 103; the lower end of the upper limit rib 106 is a free end, and the upper end of the lower limit rib 107 is a free end; the upper limit rib 106 and the corresponding lower limit rib 107 are both in the shape of a straight plate or a straight rod; the axis of the upper limit rib 106 coincides with or is parallel to the axis of the upper deformation block 104, and the axis of the lower limit rib 107 coincides with or is parallel to the axis of the lower deformation block 105, so that the upper limit rib 106 can move downward and outward ("outward" is the direction away from the axis of the bracket unit 1, and "inward" is the direction close to the axis of the bracket unit 1) with the expansion of the upper deformation block 104, and the upper limit rib 106 moves upward and outward with the expansion of the lower deformation block 105, and the opposite is true when the upper deformation block 104 and the lower deformation block 105 contract.

[0041] When the upper deformable ring 101 and the lower deformable ring 102 are deformed synchronously (i.e., the degree of expansion and contraction is the same), the upper limit rib 106 and the corresponding lower limit rib 107 maintain a specific matching relationship. When the stent unit 1 expands and shortens (its inner diameter expands and its length shortens), the upper limit rib 106 and the corresponding lower limit rib 107 continue to approach each other, and the degree of overlap between the two gradually increases, and finally they are locked together through a locking structure. This locking is unidirectional, so that even if the external force disappears, the stent unit 1 cannot retract, thereby ensuring that the vascular stent has sufficient expansion force.

[0042] Another key improvement of the medical absorbable thoracic aorta stent system provided in this embodiment is that when the upper deformable ring 101 and the lower deformable ring 102 are asynchronously expanded to a set state under the action of the operating balloon 2, the locking structure between the upper limit rib 106 and the corresponding lower limit rib 107 is released and the restriction on the retraction of the stent unit 1 is released.

[0043] Asynchronous expansion means that the upper deformable ring 101 and the lower deformable ring 102 have different expansions, for example, the upper deformable ring 101 expands, while the lower deformable ring 102 remains unchanged or expands (due to the connecting effect of the first connecting rib 103, the lower deformable ring 102 may expand in actual operation, but the expansion degree is not as good as the upper deformable ring 101). In this embodiment, after the upper deformable ring 101 and the lower deformable ring 102 expand to a certain and the same degree, they cannot retract due to the locking of the locking structure. At this time, when the upper deformable ring 101 is controlled to continue to expand by operating the balloon 2 alone, the locking structure can be unlocked. After unlocking and removing the external force, the upper deformable ring 101 and the lower deformable ring 102 retract to a state where they can remain free, and the stent unit 1 can be expanded again through the balloon.

[0044] With this structure, the aortic stent with deviations in expansion degree or placement position can be remedied. Otherwise, if it is only locked in one direction, the stent has a low error tolerance rate, and once a deviation occurs, the consequences are difficult to make up for. In existing medical operations, this deviation often occurs, causing medical staff to spend more time on making up for the error.

[0045] In terms of specific structure, there is a gap between the upper limit rib 106 and the corresponding lower limit rib 107; the locking structure includes a locking block 108 and a plurality of locking grooves 109 for the locking block 108 to be inserted into; a locking block 108 is protruded from one side of the lower limit rib 107, and a plurality of stoppers 110 are protruded from the side of the upper limit rib 106 opposite to the lower limit rib 107, and a locking groove 109 is formed between adjacent stoppers 110; when the upper deformable ring 101 and the lower deformable ring 102 are synchronously expanded under the action of the operating balloon 2 and cause the stent unit 1 to expand and shorten, the locking block 108 moves and crosses the stopper 110 to enter the locking groove 109; when the upper deformable ring 101 and the lower deformable ring 102 are asynchronously expanded under the action of the operating balloon 2, the upper limit rib 106 and the lower limit rib 107 gradually move away from each other and cause the locking block 108 to escape from the locking groove 109.

[0046] The locking block 108 can be inserted into different locking grooves 109, and once it enters the locking groove 109, it cannot be withdrawn when the upper deformation ring 101 and the lower deformation ring 102 expand synchronously, and can only continue to move upward, that is, the bracket unit 1 can only continue to expand and shorten. At this time, as a preference, the blocks 110 on the same lower limit rib 107 are evenly distributed along the length direction of the lower limit rib 107, the blocks 110 are wedge-shaped and their inclined surfaces are set downward, and the locking block 108 is provided with an arc surface on one side facing the inclined surface of the block 110, and the arc surface of the locking block 108 can reduce the resistance of its movement on the inclined surface of the block 110, and once it crosses the inclined surface of the block 110, it enters the locking groove 109. The locking block 108 can be arranged at the top of the lower limiting rib 107 or near the top; the number of the blocking blocks 110 can be determined according to the needs, and the multiple locking grooves 109 formed by the multiple blocking blocks 110 make the locking structure have a multi-level locking function and can be used according to the needs.

[0047] The upper limit rib 106 is opposite to the corresponding lower limit rib 107 but is not located on the same straight line. Preferably, the upper limit rib 106 is located outside the corresponding lower limit rib 107. Therefore, when the upper limit rib 106 moves outward alone, the distance between the locking groove 109 and the locking block 108 increases continuously until the distance is greater than the lateral width of the locking block 108, and the locking structure can be unlocked.

[0048] In this embodiment, the expansion device adapted to the bracket unit 1 also has a special structure; the operating balloon 2 includes a first balloon body 201 for driving the upper deformable ring 104 to expand and a second balloon body 202 for driving the lower deformable ring 105 to expand, and the bottom of the first balloon body 201 and the top of the second balloon body 202 are connected by a first connecting tube 203; the inflation device includes a first inflator 301 and a second inflator 302, the first balloon body 201 is connected to the air supply end of the first inflator 301 through a first ventilation tube 303, and the second balloon body 202 is connected to the air supply end of the second inflator 302 through a second ventilation tube 304, and the first ventilation tube 303 and the second ventilation tube 304 are independently arranged.

[0049] The first balloon body 201 and the second balloon body 202 are independently inflated and deflated, so that the upper deformable ring 104 and the lower deformable ring 105 can be independently expanded and controlled; when the first balloon body 201 and the second balloon body 202 are inflated to the same degree, the upper deformable ring 104 and the lower deformable ring 105 are expanded synchronously; when the gas filled into the first balloon body 201 is more than the gas filled into the second balloon body 202, the upper deformable ring 104 and the lower deformable ring 105 are expanded asynchronously. In specific implementation, the second vent pipe 304 can pass through the first balloon body 201 and the first connecting pipe 203 and enter the second balloon body 202.

[0050] In order to facilitate the control of the filling and discharging of the gas in the first balloon body 201 and the second balloon body 202, the expansion device also includes a first pressure sensor 305 connected to the first ventilation tube 303 for detecting the internal pressure of the first balloon body 201 and a second pressure sensor 306 connected to the second ventilation tube 304 for detecting the internal pressure of the second balloon body 202. When the internal pressure values ​​detected by the first pressure sensor 305 and the second pressure sensor 306 are the same, it can be considered that the first balloon body 201 and the second balloon body 202 are inflated to the same degree. In actual use, the first pressure sensor 305 and the second pressure sensor 306 can be connected to a display through a processor, or directly connected to a host computer (such as a portable computer).

[0051] In addition, in order to adapt to the deformation characteristics of the stent unit 1 and ensure effective expansion control of the upper deformable ring 104 and the lower deformable ring 105, the first balloon body 201 and the second balloon body 202 have the same shape and are both elliptical (or gyro-shaped, frustum-shaped, etc.). When in use, the part with a larger inner diameter of the first balloon body 201 can correspond to the middle part of the upper deformable ring 104, and the part with a larger inner diameter of the second balloon body 202 can correspond to the middle part of the lower deformable ring 105.

[0052] Embodiment 2

[0053] like Figure 5 and Figure 6 As shown, a medical absorbable thoracic aortic stent system provided in this embodiment includes two stent units 1, and the upper and lower adjacent stent units 1 are connected by a second connecting rib 5. The structure of the stent unit 1 is the same as that shown in Example 1. Through the axial connection of the stent unit 1, the length of the thoracic aortic stent can be extended according to medical needs; of course, by the same token, three, four or even more axial stent units 1 can be connected, and the thoracic aortic stent is a straight structure as a whole and is not bent.

[0054] The upper end of the second connecting rib 5 is fixedly connected to the bottom of the trough of the lower deformation ring 102 of the upper bracket unit 1 , and the lower end is fixedly connected to the top of the peak of the corresponding upper deformation ring 101 of the adjacent lower bracket unit 1 .

[0055] In this embodiment, in the case of multiple support units 1, the number of the operating balloons 2 is the same as the number of the support units 1; in two adjacent operating balloons 2, the second balloon body 202 of the previous operating balloon 2 is connected to the first balloon body 201 of the next operating balloon 2 through a second connecting tube; the first balloon bodies 201 are connected through a first connecting tube 203, and the second balloon bodies 202 are connected through a second connecting tube 204.

[0056] The structure of the operating balloon 2 is the same as that of the embodiment 1. Through the axial connection of the operating balloon 2, the length of the expansion device can be extended according to medical needs, so that the expansion device can be adapted to the length of the thoracic aorta stent.

[0057] When the locking structure needs to be unlocked, the thoracic aortic stent can be expanded to a certain and identical degree by operating the balloon 2, and then the upper deformable ring 101 can be expanded by the first balloon body 201. After unlocking, the gas in the first balloon body 201 and the second balloon body 202 is released at the same time, and the thoracic aortic stent is expanded again by operating the balloon 2 after waiting for it to return to its natural state.

[0058] Finally, it should be noted that this article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only to help understand the core idea of ​​the present invention. Without departing from the principles of the present invention, the present invention may also be improved and modified, and these improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A medical absorbable thoracic aortic stent system, comprising a stent unit made of absorbable material and an expansion device for expanding the stent unit; The bracket unit comprises an upper deformation ring, a lower deformation ring arranged below the upper deformation ring, and a plurality of first connecting ribs for connecting the upper deformation ring and the lower deformation ring axially; the upper deformation ring is connected in sequence along the circumferential direction by a plurality of upper deformation blocks to form a wavy annular structure, the lower deformation ring is connected in sequence along the circumferential direction by a plurality of lower deformation blocks to form a wavy annular structure, and the upper deformation blocks and the lower deformation blocks are arranged in a manner of staggered wave crests and wave troughs, the upper end of the first connecting rib is fixedly connected to the bottom of the wave trough of the upper deformation ring, and the lower end is fixedly connected to the top of the wave crest of the corresponding lower deformation ring; The expansion device comprises an operating balloon and an inflation device, wherein the operating balloon is used to extend into the stent unit and to be inflated by the inflation device; the feature is: The stent unit further comprises a plurality of upper limit ribs and lower limit ribs arranged along its axial direction, wherein the upper end of the upper limit rib is fixedly connected to the bottom of the wave crest of the upper deformation ring, and the lower end of the lower limit rib is fixedly connected to the top of the wave trough of the corresponding lower deformation ring; when the upper deformation ring and the lower deformation ring are synchronously expanded under the action of the operating balloon and cause the stent unit to expand and shorten, the upper limit rib and the corresponding lower limit rib are locked with each other through the locking structure and prevent the stent unit from retracting; When the upper deformation ring and the lower deformation ring are asynchronously expanded to a set state under the action of the operating balloon, the locking structure between the upper limit rib and the corresponding lower limit rib is unlocked and the restriction on the retraction of the stent unit is released; There is a gap between the upper limit rib and the corresponding lower limit rib; the locking structure includes a locking block and a plurality of locking grooves for the locking block to be inserted into; a locking block is protruded from one side of the lower limit rib, and a plurality of stoppers are protruded from the side of the upper limit rib opposite to the lower limit rib, and a locking groove is formed between adjacent stoppers; when the upper deformation ring and the lower deformation ring expand synchronously under the action of the operating balloon and cause the bracket unit to expand and shorten, the locking block moves and crosses the stopper to enter the locking groove; when the upper deformation ring and the lower deformation ring expand asynchronously under the action of the operating balloon, the upper limit rib and the lower limit rib gradually move away from each other and cause the locking block to escape from the locking groove.

2. A medical absorbable thoracic aortic stent system according to claim 1, characterized in that: The blocks on the same lower limiting rib are evenly distributed along the length direction of the lower limiting rib, the block is wedge-shaped and its inclined surface is arranged downward, and the locking block is provided with an arc surface on one side facing the inclined surface of the block.

3. A medical absorbable thoracic aortic stent system according to claim 1, characterized in that: The upper limit rib and the corresponding lower limit rib are both in the shape of a straight plate or a straight rod.

4. The medical absorbable thoracic aortic stent system according to claim 1, characterized in that: The upper limit rib is located outside the corresponding lower limit rib.

5. A medical absorbable thoracic aortic stent system according to any one of claims 1 to 4, characterized in that: The operating balloon includes a first balloon body for driving the upper deformable ring to expand and a second balloon body for driving the lower deformable ring to expand, and the bottom of the first balloon body is connected to the top of the second balloon body through a first connecting tube; the inflation device includes a first inflator and a second inflator, the first balloon body is connected to the air supply end of the first inflator through a first ventilation tube, and the second balloon body is connected to the air supply end of the second inflator through a second ventilation tube, and the first ventilation tube and the second ventilation tube are independently arranged.

6. The medical absorbable thoracic aortic stent system according to claim 5, characterized in that: The expansion device also includes a first pressure sensor connected to the first ventilation tube for detecting the internal pressure of the first balloon and a second pressure sensor connected to the second ventilation tube for detecting the internal pressure of the second balloon.

7. The medical absorbable thoracic aortic stent system according to claim 5, characterized in that: The medical absorbable thoracic aorta stent system comprises two or more stent units, and the upper and lower adjacent stent units are connected by a second connecting rib; The number of the operating balloons is the same as the number of the bracket units; in two adjacent operating balloons, the second balloon body of the previous operating balloon is connected to the first balloon body of the next operating balloon through a second connecting tube; the first balloon bodies are connected through the first connecting tube, and the second balloon bodies are connected through the second connecting tube.

8. The medical absorbable thoracic aortic stent system according to claim 5, characterized in that: The first balloon body and the second balloon body have the same shape and are both elliptical, gyro-shaped or frustum-shaped.

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