CN108309506B

CN108309506B - vena cava filter

Info

Publication number: CN108309506B
Application number: CN201810225075.8A
Authority: CN
Inventors: 刘建龙; 苏宏东; 娄德大; 高祥凯
Original assignee: Weihai Visee Medical Devices Co ltd
Current assignee: Weihai Visee Medical Devices Co ltd
Priority date: 2018-03-19
Filing date: 2018-03-19
Publication date: 2023-10-13
Anticipated expiration: 2038-03-19
Also published as: CN108309506A

Abstract

The invention relates to a vena cava filter, which comprises recovery hooks at two ends, wherein the recovery hooks are respectively connected with net baskets, and two opposite net baskets are connected through ribs; the rib comprises a non-degradable section and a degradable section, wherein the two ends of the non-degradable section are connected with the basket, and the degradable section is arranged between the two non-degradable sections and is connected with the non-degradable section. The rib of the filter is arranged into a structure that the middle degradable section and the two ends are combined with the non-degradable section, so that the degradable section can be completely degraded after the filter is placed into a blood vessel in a body. When the degradable section is complete, the filter is converted into two independent filters, the combination length of the nondegradable section of the rib and the blood vessel wall is shortened, the contact area is reduced, the filters at the two ends can be conveniently recovered along the direction of the rib, the stability, the safety and the reliability of the filter can be maintained, and the filters at the two ends can be recovered simply and conveniently at any time. The invention has reasonable structure, safety, stability, reliable performance and convenient operation and use, and is an ideal switchable vena cava filter.

Description

Vena cava filter

Technical Field

The invention belongs to the field of medical appliances, and particularly relates to a vena cava filter.

Background

Deep vein thrombosis (deep venous thrombosis, DVT) of the lower extremities is a clinically common disease and is the most leading cause of pulmonary arterial embolism (PE), and has high mortality and disability rate of pulmonary embolism. The placement of the inferior vena cava filter (inferior vena cava filter, IVCF) can effectively prevent PE, making thrombolytic therapy safer. The basic principle is that a filter screen device is placed below the level of the renal vein opening to catch and intercept free emboli in blood and prevent the free emboli from entering the pulmonary circulation. Therefore, the occurrence of pulmonary embolism can be effectively prevented, and the technology is gradually popularized and popularized at home and abroad in recent years.

Since the first vena cava filter in the sixties, more than ten products have been used clinically at home and abroad. However, various filters currently in popular use have more or less drawbacks of their own, in that after the vena cava filter is implanted in a human body, vascular endothelial cells rapidly proliferate and grow, so that the filter rapidly endothelializes blood vessels and is easily combined with blood vessels to form a part of the body. If the filter is recovered before the filter is completely endothelialized, the filter is placed in the body for a short time, so that the treatment effect is affected; if the treatment effect is achieved, the medical implant is recovered after the operation for a long time, larger damage is caused to the blood vessel of the human body, the difficulty is increased, the medical implant is not suitable to be taken out, the permanent implant is easy to cause other damages such as complications to the local blood vessel and organs of the local blood vessel after the operation, and the medical implant needs to be maintained by medicaments. In order to solve the problem, a degradable filter can be theoretically adopted to solve the problem that the degradable filter is difficult to recover for a long time after being placed, but the degradation time of the material is difficult to control, the strength and stability of the filter are affected in the degradation process, and the effect is not ideal as the effect of degrading large residues falling off in blood vessels is difficult to estimate.

Chinese patent application inferior vena cava filter and its retraction system (publication No. CN 105578989A) discloses a device for delivery or retraction of vascular medical devices, in particular an elongate sleeve, and an elongate shaft received within the sleeve, the shaft having a flexible distal extension that folds back inwardly at a distal opening and forms a more proximal opening; and the device is adapted such that the enlarged end of the medical device is secured in the pocket within the distal extension as the sleeve is advanced over the distal extension. The inferior vena cava filter is a temporary filter and needs to be recovered in a later period, and mainly solves the problems that the inferior vena cava filter is more convenient to recover and is not easily affected by the orientation of the filter.

Chinese patent application "vena cava filter" (publication No. CN 104352287A), specifically discloses that the vena cava filter is placed at the inferior vena cava position between the renal vein and the iliac vein, is formed by integral laser cutting of a nitinol tube, and includes: connecting rod, the top layer filter screen that forms cage structure jointly, middle level filter screen and bottom filter screen, just the middle level filter screen is located between top layer filter screen and the bottom filter screen, by the branch incurvate formation that many cuts out, the top layer filter screen with the middle level filter screen can catch the great thrombus of interception, the lower thrombus of interception can be caught to the bottom filter screen, and this three-layer filter screen surface parcel PTFE film, the connecting rod contacts and connects with the vascular wall cage structure, just the connecting rod detachable becomes the branch more than two, expansion shaping to the PTFE film is gone up in the parcel. The vena cava filter has good thrombus filtering effect, can be repeatedly and firmly positioned, can prolong the implantation time, can be recycled, and can delay the endothelialization effect.

However, both vena cava filters fail to solve the two contradictory problems of good stability after placement and short recovery time window.

Disclosure of Invention

According to the defects, the invention aims to provide the vena cava filter which has the advantages of simple and reasonable structure, reliability, simple and convenient operation, high safety and longer recovery window period.

In order to achieve the above purpose, the technical scheme of the invention is as follows: the vena cava filter comprises recovery hooks at two ends, wherein the recovery hooks are respectively connected with the mesh baskets, and the two mesh baskets which are oppositely arranged are connected through ribs; the rib comprises a non-degradable section and a degradable section, wherein the two ends of the non-degradable section are connected with the basket, and the degradable section is arranged between the two non-degradable sections and is connected with the non-degradable section.

Preferably, it is: the non-degradable section is made of nickel-titanium alloy material.

Preferably, it is: the degradable section is a magnesium alloy material or a degradable polymer material.

Preferably, it is: the types and contents of other elements in the magnesium alloy material are different according to the required degradation speed.

Preferably, it is: the type of degradable polymeric material and its relative molecular mass vary according to the desired degradation rate.

The invention also provides a processing method of the vena cava filter, which comprises the steps of controlling the discharging and moving track of the nozzle according to the shape of the set vena cava filter through a three-dimensional printing system, and orderly printing and forming the non-degradation sections and degradation sections of the recovery hooks, the mesh baskets and the ribs according to a set program.

The invention also provides equipment for processing the vena cava filter, which comprises a control unit, a plurality of material filling units, an imaging unit and a high-voltage power supply laser, wherein the material filling units are connected with the control unit, each material filling unit comprises a powder filling component and a nozzle connected with the material filling component, a substrate for supporting the vena cava filter is arranged below each material filling unit, an inert gas protection unit is arranged on the periphery of each nozzle, and each imaging unit comprises a light source, a microscope and a display.

The invention also provides for the use of a vena cava filter that converts to two separate filters that are separately recovered when the degradable segment of the rib is fully degraded.

The invention has the beneficial effects that: the rib of the filter is arranged into a structure that the middle degradable section and the two ends are combined with the non-degradable section, so that the degradable section can be completely degraded after the filter is placed into a blood vessel in a body. When the degradable section is complete, the filter is converted into two independent filters, the combination length of the nondegradable section of the rib and the blood vessel wall is shortened, the contact area is reduced, the filters at the two ends can be conveniently recovered along the direction of the rib, the stability, the safety and the reliability of the filter can be maintained, and the filters at the two ends can be recovered simply and conveniently at any time. The invention has reasonable structure, safety, stability, reliable performance and convenient operation and use, and is an ideal switchable vena cava filter.

Drawings

FIG. 1 is a schematic diagram of the structure of the present invention;

FIG. 2 is a schematic structural view of a rib of the present invention;

FIG. 3 is a schematic structural view of the degradable segment of the rib of the present invention after degradation;

fig. 4 is a schematic structural view of the three-dimensional printing apparatus of the present invention;

fig. 5 is an enlarged schematic view of a nozzle portion in the three-dimensional printing apparatus of the present invention.

In the figure, the I-non-degrading moiety; II-a degradable moiety; III-a non-degrading moiety; 1-a recovery hook; 2-basket; 3-anchoring the anchor; 4-ribs; 5-a control unit; 6-microscopy; 7-a substrate; 8-a light source; 9-a high voltage power supply laser; 10-a powder filling assembly; 11-nozzles; 12-an inert gas chamber; a-a non-degradation section; b-a degradable segment; c-non-degradation stage.

Detailed Description

The invention will be further illustrated with reference to specific examples.

As can be seen from fig. 1, a vena cava filter comprises three sections i, ii and iii, wherein i and iii are non-degradable parts, and can be processed from nickel-titanium alloy powder, has high elasticity and high strength, and is in a spindle-shaped net shape; the middle III section is a degradable part and is formed by processing a degradable material magnesium alloy or a degradable high polymer, and the middle III section is connected with the I section and the III section.

Specifically, the vena cava filter comprises recovery hooks 1 positioned at two ends, wherein the recovery hooks 1 are respectively connected with the net baskets 2, and the two net baskets 2 which are oppositely arranged are connected through ribs 4; the rib 4 comprises non-degradable sections a, c connected at both ends to the basket 2 and a degradable section b disposed intermediate and connected to the non-degradable sections a, c. The two ends of the filter are both provided with the net basket 1 and the recovery hook 2, so that after the degradable section is completely degraded, the original filter is changed into two independent upper and lower filters, the two ends I and III can continuously act, can be respectively recovered from the upper and lower passages, can be singly recovered and can also be simultaneously recovered, and the filter is very flexible.

The two ends of the rib 4 are connected with the basket 2 to form a memory metal nickel-titanium alloy, and the middle degradable section b is a magnesium alloy or a degradable high polymer. In the initial stage of the placement in the body, the filter is fixed on the vessel wall under the action of the fixing anchors 3, the a, b and c sections of the rib 4 are contacted with the vessel wall, and are combined together after endothelialization, so that the filter is safe and reliable and does not shift in the process.

The rib 4 is characterized in that the middle degradable section b is uniformly corroded and degraded in the body, and the nickel-titanium alloy ribs at the two ends a and c are continuously combined with the endothelialized vessel wall. The length of the three sections a, b and c of the rib 4 can be controlled according to the actual requirements, wherein the length of the three sections a, b and c can be designed in advance according to the actual requirements, namely the contact area with vascular endothelialization can be controlled.

After the degradable section b of the rib 4 is degraded, the contact area between the nondegradable sections a and c and vascular endothelialization is controlled by design, so that the two sections of filters in the body have certain retention force, the stability and the non-displacement of the filters in the body are ensured, and the filters are easy to recover during recovery and do not damage the inferior vena cava.

Wherein, the types and the contents of other elements in the magnesium alloy material are different according to the different degradation speeds. The degradation rate of the degradable section can be controlled by controlling the variety and the content of other elements in the magnesium alloy, so that the degradation time of the degradable section can be controlled.

The same reason is that the type of degradable polymeric material and its relative molecular mass vary according to the desired degradation rate. The degradation rate of the degradable section can be controlled by the variety and the relative molecular mass of the degradable polymer composite material, so that the degradation time of the degradable section can be controlled.

The invention also provides a processing method of the vena cava filter, which comprises the steps of controlling the discharging and moving track of the nozzle according to the shape of the set vena cava filter through a three-dimensional printing system, and orderly printing and forming the non-degradation sections and degradation sections of the recovery hooks, the mesh baskets and the ribs according to a set program. And performing heat treatment setting on the printed vena cava filter. In this process, the control unit controls the switching between the different nozzles when the different materials are switched. Nozzle as shown in fig. 5, powder material enters the nozzle through the intelligent feeding system under the protection of inert gas, and the temperature of sintered powder is controlled by adjusting a high-voltage power supply and laser parameters, so that the nozzle prints according to the requirement.

Of course, besides the three-dimensional printing method for processing the filter, a welding mode can be adopted, and the heat treatment shaping treatment can be carried out after welding.

On one hand, the three-dimensional printing method is used for printing the vena cava filter, is convenient for rapid integrated forming, and solves the problem of difficult combination among different materials.

On the other hand, the three-dimensional printing method is used for printing the vena cava filter, is convenient for controlling the material, and can control the degradation rate of the degradable section by controlling the composition or the content or the molecular weight of the material, thereby solving the problem of unification of the filter material obtained by the traditional processing method.

Furthermore, the three-dimensional printing method is used for printing the vena cava filter, and can design specific requirements of the length, the diameter, the structural shape and the like of the filter according to actual needs, so that the problem that the specifications of the filters obtained by the traditional processing method are the same is solved. For example, a conventional vena cava filter (product number XJLX 3260) has a diameter of 32mm and a blood vessel diameter of 16-30mm is recommended, but when the blood vessel diameter is smaller than 16 or larger than 30mm, there is a possibility that the filtering effect is poor. Moreover, the conventional vena cava filters are mass-produced, and not only are the sizes fixed, but also the filters with different sizes cannot be realized, because the grinding tools are fixed, the grinding tools are required to be replaced when the filters with nonstandard specifications are required to be produced, the cost and the field requirement for replacing the grinding tools are high, the demand of nonstandard specifications is small, and moreover, the sizes of the nonstandard filters which may be required by different patients are different, so that the conventional filter production process cannot solve the problems. And filters of different sizes can be tailored to suit the vascular conditions of different patients by the method of the present invention. The flexibility is extremely high, the burden of enterprises is greatly reduced, and meanwhile, a filter which is more suitable for the blood vessels of the patients can be provided for the patients.

The device for processing the vena cava filter comprises a control unit 5, a plurality of material filling units, an imaging unit and a high-voltage power supply laser 9, wherein the material filling units are connected with the control unit 5, each material filling unit comprises a powder filling assembly 10 and a nozzle 11 connected with the material filling assembly 10, a substrate 7 for supporting the vena cava filter is arranged below the material filling unit, and an inert gas protection unit is arranged on the periphery of each nozzle 11. The inert gas protection unit is an inert gas protection chamber 12 filled with inert gas, and the imaging unit comprises a light source 8 and a microscope 6, and the control unit 5 is also a display instrument.

The two ends of the main body are printed by using memory metal nickel-titanium alloy, the middle degradable section is made of degradable magnesium alloy or degradable high polymer, namely, the section where the a and c of the rib 4 are combined with the basket 2 is made of nickel-titanium alloy, the middle b of the rib is a degradable section, and the three sections of the rib are designed and controlled according to specific conditions. After placement of the filter, the endothelial cells proliferate and grow rapidly in the vessel wall, and endothelialising and growing together with the vessel wall takes about two weeks. Therefore, the filter is easy to recycle within two weeks after being placed and before incomplete endothelialization, and has less damage to the blood vessel of the human body; after two weeks, the filter was endothelialized and not suitable for recovery.

According to the invention, a degradable material magnesium alloy or a degradable high molecular polymer is used in the middle rib part of the filter main body, a novel three-dimensional printing rapid forming technology is utilized, the memory metal nickel titanium alloy and the degradable material are integrally formed, the filter main body constituent materials are changed, the structure is optimized, the action effect of breaking free emboli of the existing popular filter nickel titanium alloy is reserved, the vena cava is not damaged, the displacement is not caused, and the retention force of endothelialization combination of the filter and the vascular wall is controlled. The defects that the filter recovery time is limited and the recovery is difficult due to vascular endothelialization of the similar filter in the prior art are avoided. The invention has reasonable structure, optimizes the structure of the composition materials, is safe and reliable, and makes it possible to recover the filter at any time after the filter operation.

Claims

1. The vena cava filter comprises recovery hooks at two ends, wherein the recovery hooks are respectively connected with the basket, and the two opposite baskets are connected through ribs; the method is characterized in that: the rib comprises a non-degradation section and a degradable section, wherein both ends of the non-degradation section are connected with the basket, and the degradable section is arranged between the two non-degradation sections and is connected with the non-degradation section; the degradable section is made of magnesium alloy material or degradable polymer material; after the degradable segment of the rib has been fully degraded, the vena cava filter is converted into two separate filters, which are separately recovered.

2. A vena cava filter as in claim 1, wherein: the non-degradation section is made of nickel-titanium alloy material.

3. A vena cava filter as in claim 1, wherein: the types of other elements and the content of other elements in the magnesium alloy material are different according to the different degradation speeds.

4. A vena cava filter as in claim 1, wherein: the types and the relative molecular masses of the degradable high molecular materials are different according to the different degradation speeds.

5. A method of manufacturing a vena cava filter as claimed in any one of claims 1 to 4, wherein: and controlling the discharging and moving track of the nozzle through a three-dimensional printing system according to the shape of the set vena cava filter, and orderly printing and forming the non-degradation sections and degradation sections of the recovery hooks, the mesh basket and the ribs according to a set program.