A filter device for the inferior vena cava

Abstract

The application relates to a filter device for inferior vena cava, belonging to the technical field of medical instruments, and solves the problem that an inferior vena cava filter screen may be inclined and cannot be smoothly taken out of a blood vessel during implantation operation in the prior art. The application comprises a front positioning unit, a filter screen unit and a rear positioning unit, the filter screen unit is sleeved on the front positioning unit, and the rear positioning unit is sleeved on the filter screen unit; the front positioning unit and the rear positioning unit are both used for being unfolded first, and the unfolded positioning of the filter screen unit unfolded subsequently. The first positioning point of the front positioning unit and the second positioning point of the rear positioning unit are both on the center line of the front positioning sleeve, after the filter screen assembly is unfolded, the front positioning sleeve can ensure that the center line of the filter screen assembly coincides with the center line of the inferior vena cava blood vessel, the filter screen assembly cannot be inclined in the inferior vena cava blood vessel, and the filter screen assembly can be smoothly taken out of the inferior vena cava blood vessel subsequently.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, in particular to a filter device for inferior vena cava. BACKGROUND

[0002] Deep vein thrombosis of lower extremity is one of the common vascular diseases, and its incidence is increasing year by year. In order to prevent the occurrence of pulmonary embolism, inferior vena cava filter implantation as a common diagnosis and treatment method is widely used in clinical practice.

[0003] The inferior vena cava filter can effectively intercept the deep vein thrombosis of lower extremity from entering the pulmonary circulation, thereby preventing the occurrence of pulmonary embolism.

[0004] At present, the long-term indwelling inferior vena cava filter used in clinical practice is mostly in the shape of an umbrella. During the implantation operation, there is a possibility of tilting, and even the tip of the umbrella-shaped structure may stick to the blood vessel wall. When the later operation needs to be taken out from the inferior vena cava, the tip of the umbrella-shaped structure cannot be hooked, and the inferior vena cava filter cannot be smoothly taken out, which may cause blood vessel hyperplasia and adhesion, increasing the risk of further open surgery.

[0005] At present, there is no effective design to prevent the problems such as tilting, angling and sticking to the wall during the implantation of the inferior vena cava filter. SUMMARY

[0006] In view of the above shortcomings of the prior art, the present application provides a filter device for inferior vena cava, which solves the problem that the inferior vena cava filter may tilt during the implantation operation and cannot be smoothly taken out from the blood vessel.

[0007] To achieve the above-mentioned purposes, the technical scheme adopted by the present application is as follows:

[0008] The present application provides a filter device for inferior vena cava, which comprises a front positioning unit, a filter unit and a rear positioning unit. The filter unit is sleeved on the front positioning unit, and the rear positioning unit is sleeved on the filter unit. The front positioning unit and the rear positioning unit are both used for unfolding in the inferior vena cava, positioning for subsequent unfolding of the filter unit. The inferior vena cava filter of the filter unit can remain non-tilting during the implantation operation, and can be smoothly taken out from the inferior vena cava blood vessel later.

[0009] Further, the front positioning unit comprises a front positioning branch and a push-pull strip, one end of the front positioning branch and the push-pull strip is connected, and the other end of the push-pull strip is a free end.

[0010] Further, the front positioning unit further comprises a front positioning sleeve, the front positioning branch and the push-pull strip are both arranged in the front positioning sleeve, and the filter unit is arranged on the front positioning sleeve.

[0011] Further, the front positioning branches are arranged in multiple and are evenly distributed on the end face of the front positioning sleeve along the center line of the front positioning sleeve.

[0012] Further, the front positioning branches are elastic positioning branches, which can be pushed out of the front positioning sleeve by the front positioning sleeve and radially expanded.

[0013] Further, the front positioning branches are elastic positioning branches, which can be pushed out of the front positioning sleeve by the front positioning sleeve and radially expanded.

[0014] Further, the filter screen unit comprises a filter screen assembly, a filter screen push-pull sleeve and a filter screen protection tube, the filter screen assembly is detachably connected with the filter screen push-pull sleeve, the filter screen assembly and the filter screen push-pull sleeve are sleeved on the front positioning sleeve, and the filter screen assembly and the filter screen push-pull sleeve are arranged in the filter screen protection tube.

[0015] Further, the rear positioning unit comprises rear positioning branches, a rear positioning sleeve and a rear protection tube, the rear positioning branches and the rear positioning sleeve are arranged in the rear protection tube, and one end of the rear positioning branches and the rear positioning sleeve is connected.

[0016] Further, the rear positioning branches are arranged in multiple and are evenly distributed on the end face of the rear positioning sleeve along the center line of the rear positioning sleeve.

[0017] Further, the rear positioning branches are elastic positioning branches, which can be pushed out of the rear protection tube by the rear positioning sleeve and radially expanded.

[0018] Compared with the prior art, the present application can at least achieve one of the following beneficial effects:

[0019] (1) The first positioning point of the front positioning unit and the second positioning point of the rear positioning unit are on the center line of the front positioning sleeve, after the front positioning branches and the rear positioning branches are expanded, the center line of the front positioning sleeve can coincide with the center line of the inferior vena cava, after the filter screen assembly is expanded, the front positioning sleeve can ensure that the center line of the filter screen assembly coincides with the center line of the inferior vena cava, so that the filter screen assembly cannot be skewed in the inferior vena cava, and the filter screen assembly can be smoothly taken out of the inferior vena cava;

[0020] (2) The first sleeve and the second sleeve of the present application jointly position the filter screen assembly, further ensuring that the filter screen assembly cannot be skewed in the inferior vena cava; the filter screen assembly is in the shape of a date pit, the contact area between the filtering branches and the blood vessel wall is increased, and the placement of the filter screen assembly in the blood vessel is more stable;

[0021] (3) The invention can be inserted into the connecting horizontal groove and connected with the connecting horizontal groove, and prevent the connecting sleeve from being separated from the first sleeve; one end of the leaf spring is connected with the clamping pin, and the other end of the leaf spring is connected with the clamping pin groove, the leaf spring is used for ejecting the clamping pin from the clamping pin groove, and the clamping pin is kept connected with the connecting horizontal groove, preventing the connecting sleeve from being separated from the first sleeve;

[0022] (4) The user rotates the sleeve body of the invention, which can drive the connecting sleeve to rotate, the unlocking slope can be connected with the inner wall of the first sleeve, and the connecting sleeve is further rotated, under the limitation of the inner wall of the first sleeve, the clamping pin body is pressed into the clamping pin groove, until the clamping pin body is separated from the connecting horizontal groove; at this time, the user pulls the sleeve body outward, the connecting sleeve can be axially separated from the first sleeve, the sleeve body can be taken out from the venous blood vessel, and the filter screen assembly placement operation is completed;

[0023] (5) The connecting sleeve of the invention is rotated, the clamping pin can be ejected by the leaf spring and connected with the clamping groove; the user can feel obvious paragraph feeling and resistance feeling of rotating the connecting sleeve, so that the user confirms that the clamping pin body is separated from the connecting horizontal groove, and the axially arranged clamping groove can prevent the clamping pin from being connected with the connecting horizontal groove, and guide the connecting sleeve to be axially separated from the first sleeve, which is convenient for the user to operate.

[0024] In the present invention, the above technical solutions can be combined with each other to realize more preferred combination schemes. Other features and advantages of the present invention will be described in the following content, and some advantages will become apparent from the description, or will be understood by implementing the present invention. The purposes and other advantages of the present invention can be realized and obtained through the contents specifically pointed out in the text and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is the overall structure schematic diagram of the filter device of the present invention;

[0026] Figure 2 It is the overall structure schematic diagram of the filter screen assembly of example 1;

[0027] Figure 3 It is the overall structure schematic diagram of the filter screen assembly of example 2;

[0028] Figure 4 It is the overall structure schematic diagram of the filter screen push-pull sleeve;

[0029] Figure 5 It is the overall structure schematic diagram of the connecting clamping pin and spring.

[0030] REFERENCE SIGNS:

[0031] 1 - front positioning unit; 2 - filter screen unit; 3 - rear positioning unit; 11 - front positioning branch; 12 - push-pull strip; 13 - front positioning sleeve; 21 - filter screen assembly; 22 - filter screen push-pull sleeve; 23 - filter screen protection sleeve; 31 - rear positioning branch; 32 - rear positioning sleeve; 33 - rear protection sleeve; 211 - first sleeve; 212 - filter screen branch; 213 - second sleeve; 214 - connecting transverse groove; 215 - clamping groove; 221 - sleeve body; 222 - connecting sleeve; 223 - clamping lug; 224 - leaf spring; 2231 - clamping lug body; 2232 - locking plane; 2233 - unlocking inclined surface. DETAILED DESCRIPTION

[0032] The specific embodiments of the present application are described below to facilitate the understanding of the present application for those skilled in the art, but it should be clear that the present application is not limited to the scope of the specific embodiments, and for those skilled in the art, it is obvious that various changes are within the spirit and scope of the present application defined and determined by the appended claims, and all the inventions using the concept of the present application are within the scope of protection.

[0033] Example 1

[0034] A specific embodiment of the present application, as shown in Figure 1 A filter device for inferior vena cava (hereinafter referred to as filter device) includes a front positioning unit 1, a filter screen unit 2 and a rear positioning unit 3, the filter screen unit 2 is sleeved on the front positioning unit 1, and the rear positioning unit 3 is sleeved on the filter screen unit 2. The front positioning unit 1 and the rear positioning unit 3 are used to be deployed in the inferior vena cava, and the center line of the inferior vena cava is positioned, and then the filter screen unit 2 is deployed, and the center line of the filter screen unit 2 can coincide with the center line of the inferior vena cava, and the inferior vena cava filter screen of the filter screen unit 2 can keep from tilting during the implantation operation, and can be smoothly taken out from the inferior vena cava vessel subsequently.

[0035] Preferably, as shown in Figure 1As shown, the front positioning unit 1 comprises a front positioning branch 11, a push-pull strip 12 and a front positioning sleeve 13, the front positioning branch 11 and the push-pull strip 12 are both arranged in the front positioning sleeve 13, one end of the front positioning branch 11 and the push-pull strip 12 is connected, this end is the connecting end, the other end of the push-pull strip 12 is the free end, the filter screen unit 2 is arranged on the front positioning sleeve 13, and the midpoint of the connecting end of the push-pull strip 12 is the first positioning point. The front positioning branch 11 is arranged in multiple and is evenly distributed on the push-pull strip 12 along the center line of the push-pull strip 12. The front positioning branch 11 is an elastic positioning branch, which can be pushed out of the front positioning sleeve 13 by the push-pull strip 12 and radially expanded, so that the first positioning point is close to or even coincides with the center line of the inferior vena cava blood vessel, and the positioning of the filter screen unit 2 and the rear positioning unit 3 is facilitated. The front positioning branch 11 can also be pulled by the push-pull strip 12 and then be accommodated into the front positioning sleeve 13, and then the front positioning unit 1 as a whole can pass through the filter screen unit 2 and be taken out of the human body.

[0036] Preferably, the push-pull strip 12 is a steel wire rope.

[0037] Preferably, the filter screen unit 2 comprises a filter screen assembly 21, a filter screen push-pull sleeve 22 and a filter screen protection sleeve 23, the filter screen assembly 21 is detachably connected with the filter screen push-pull sleeve 22, the filter screen assembly 21 and the filter screen push-pull sleeve 22 are both sleeved on the front positioning sleeve 13, and the filter screen assembly 21 and the filter screen push-pull sleeve 22 are both arranged in the filter screen protection sleeve 23. The filter screen protection sleeve 23 is used for accommodating the filter screen assembly 21 and the filter screen push-pull sleeve 22, the filter screen push-pull sleeve 22 is used for pushing the filter screen assembly 21 out of the filter screen protection sleeve 23, and the filter screen assembly 21 can be radially expanded and used for filtering thrombus in the inferior vena cava blood vessel.

[0038] Preferably, the rear positioning unit 3 comprises a rear positioning branch 31, a rear positioning sleeve 32 and a rear protection sleeve 33, the rear positioning branch 31 and the rear positioning sleeve 32 are both arranged in the rear protection sleeve 33, and one end of the rear positioning branch 31 and the rear positioning sleeve 32 is connected, and the center point of the end surface is the second positioning point. The rear positioning branch 31 is arranged in multiple and is evenly distributed on the end surface of the rear positioning sleeve 32 around the second positioning point. The rear positioning branch 31 is an elastic positioning branch, which can be pushed out of the rear protection sleeve 33 by the rear positioning sleeve 32 and radially expanded, so that the second positioning point is close to or even coincides with the center line of the inferior vena cava blood vessel. The first positioning point and the second positioning point are both on the center line of the front positioning sleeve 13, after the front positioning branch 11 and the rear positioning branch 31 are both expanded, the center line of the front positioning sleeve 13 can coincide with the center line of the inferior vena cava blood vessel, and after the filter screen assembly 21 is expanded, the front positioning sleeve 13 can ensure that the center line of the filter screen assembly 21 coincides with the center line of the inferior vena cava blood vessel, so that the filter screen assembly 21 cannot be skewed in the inferior vena cava blood vessel, and the filter screen assembly 21 can be smoothly taken out of the inferior vena cava blood vessel in the subsequent process.

[0039] The rear positioning branch 31 can also be pulled by the rear positioning sleeve 32, and then be accommodated into the front and rear protective sleeve 33. The rear positioning unit 3 as a whole can be taken out of the blood vessel.

[0040] Preferably, as shown in Figure 2 The filter assembly 21 includes a first sleeve 211 and filter branches 212. The filter branches 212 are arranged on the end face of the first sleeve 211, and the center point of the end face is the second positioning point. The first sleeve 211 is sleeved on the front positioning sleeve 13 and detachably connected with the filter push and pull sleeve 22. The filter branches 212 are arranged in multiple and uniformly distributed along the circumferential direction of the end face of the first sleeve 211. The filter branches 212 are elastic filter branches, and the first sleeve 211 can be pushed out of the front filter protective sleeve 23 by the filter push and pull sleeve 22, and the filter branches 212 can be radially unfolded.

[0041] The filter assembly 21 is funnel-shaped or umbrella-shaped, used for intercepting thrombus. The center line of the first sleeve 211 can coincide with the center line of the inferior vena cava, so that the filter assembly 21 cannot be tilted in the inferior vena cava, and the first sleeve 211 cannot be attached to the blood vessel wall, facilitating the subsequent smooth taking out of the filter assembly 21 from the inferior vena cava.

[0042] Compared with the prior art, the first positioning point of the front positioning unit 1 and the second positioning point of the rear positioning unit 3 are both on the center line of the front positioning sleeve 13. After the front positioning branch 11 and the rear positioning branch 31 are unfolded, the center line of the front positioning sleeve 13 can coincide with the center line of the inferior vena cava. After the filter assembly 21 is unfolded, the front positioning sleeve 13 can ensure that the center line of the filter assembly 21 coincides with the center line of the inferior vena cava, so that the filter assembly 21 cannot be tilted in the inferior vena cava, and the first sleeve 211 cannot be attached to the blood vessel wall, facilitating the subsequent smooth taking out of the filter assembly 21 from the inferior vena cava.

[0043] Embodiment 2:

[0044] The umbrella-shaped filter assembly 21 has a great risk of tilting. As shown in Figure 3 In order to make the filter assembly 21 placed more firmly in the inferior vena cava, on the basis of embodiment 1, the filter assembly 21 is improved in this embodiment, so that the filter assembly 21 is placed more firmly in the inferior vena cava.

[0045] Preferably, the filter assembly 21 further comprises a second sleeve 213, the second sleeve 213 is sleeved on the front positioning sleeve 13, one end of the filter branch 212 is connected with the first sleeve 211, and the other end of the filter branch 212 is connected with the second sleeve 213. The filter assembly 21 is in the shape of a date pit. The first sleeve 211 and the second sleeve 213 jointly position the filter assembly 21, further ensuring that the filter assembly 21 will not be skewed in the inferior vena cava, and the contact area of the filter branch 212 with the blood vessel wall is increased, and the placement of the filter assembly 21 in the blood vessel is more stable.

[0046] Compared with the embodiment 1, the filter assembly 21 is in the shape of a date pit, the first sleeve 211 and the second sleeve 213 jointly position the filter assembly 21, further ensuring that the filter assembly 21 will not be skewed in the inferior vena cava, and the contact area of the filter branch 212 with the blood vessel wall is increased, and the placement of the filter assembly 21 in the blood vessel is more stable.

[0047] Embodiment 3:

[0048] Before the filter assembly 21 is placed, the filter assembly 21 and the filter push-pull sleeve 22 need to be stably connected; after the filter assembly 21 is placed, the filter assembly 21 and the filter push-pull sleeve 22 need to be quickly separated. In this embodiment, the structure of the filter assembly 21 and the filter push-pull sleeve 22 of the filter unit 2 is improved on the basis of the embodiments 1 or 2. Before the filter assembly 21 is placed, the filter assembly 21 and the filter push-pull sleeve 22 can be stably connected; after the filter assembly 21 is placed, the filter assembly 21 and the filter push-pull sleeve 22 can be quickly separated.

[0049] Preferably, as shown in Figure 3 , the filter assembly 21 further comprises a connecting transverse groove 214, the connecting transverse groove 214 is circumferentially arranged on the wall of the first sleeve 211.

[0050] Preferably, as shown in Figure 4 , the filter push-pull sleeve 22 comprises a sleeve body 221, a connecting sleeve 222, a tenon 223 and a leaf spring 224, the connecting sleeve 222 is connected with the sleeve body 221, a tenon groove (not shown in the figure) is arranged on the outer wall of the connecting sleeve 222, and the tenon 223 and the leaf spring 224 are arranged on the tenon groove. The tenon 223 can be inserted into and connected with the connecting transverse groove 214, and the connecting sleeve 222 is prevented from being separated from the first sleeve 211. One end of the leaf spring 224 is connected with the tenon 223, the other end of the leaf spring 224 is connected with the tenon groove, and the leaf spring 224 is used for making the tenon 223 pop out of the tenon groove and keeping the tenon 223 connected with the connecting transverse groove 214, so as to prevent the connecting sleeve 222 from being separated from the first sleeve 211.

[0051] Preferably, as shown in Figure 5As shown, the plate spring 224 is an arc plate spring, and the plate spring 224 can provide axial support for the tenon 223.

[0052] Preferably, the tenon 223 is a wedge-shaped tenon, and the tenon 223 includes a tenon body 2231, and the tenon body 2231 has a locking plane 2232 and an unlocking inclined plane 2233. The locking plane 2232 can abut against the connecting horizontal groove 214 and prevent the tenon 223 from being axially separated from the first sleeve 211. Twisting, i.e., circumferentially sleeving, the sleeve body 221 can drive the connecting sleeve 222 to circumferentially rotate, and the unlocking inclined plane 2233 can be connected with the inner wall of the first sleeve 211. Further rotating the connecting sleeve 222, under the limitation of the inner wall of the first sleeve 211, the tenon body 2231 is pressed into the tenon groove until the tenon body 2231 is separated from the connecting horizontal groove 214. At this time, the user pulls the sleeve body 221 outward, the connecting sleeve 222 can be axially separated from the first sleeve 211, the sleeve body 221 can be taken out of the venous blood vessel, and the filter assembly 21 placement operation is completed.

[0053] Preferably, as shown in the drawings, Figure 3 As shown, the filter assembly 21 further includes a clamping groove 215, which is axially arranged on the inner wall of the first sleeve 211 and oppositely arranged with the midpoint of the connecting horizontal groove 214. Continuing to rotate the connecting sleeve 222, the tenon 223 can be ejected by the plate spring 224 and connected with the clamping groove 215. The user can feel a clear paragraph feeling and a resistance feeling of rotating the connecting sleeve 222, which can confirm that the tenon body 2231 is separated from the connecting horizontal groove 214, and the axially arranged clamping groove 215 can prevent the tenon 223 from being connected with the connecting horizontal groove 214 and guide the connecting sleeve 222 to be axially separated from the first sleeve 211.

[0054] Compared with the first or second embodiment, the tenon 223 can be inserted into the connecting horizontal slot 214 and connected with the connecting horizontal slot 214, and prevent the connecting sleeve 222 from being separated from the first sleeve 211; one end of the flat spring 224 is connected with the tenon 223, and the other end of the flat spring 224 is connected with the tenon slot, the flat spring 224 is used to make the tenon 223 pop out of the tenon slot and keep the tenon 223 connected with the connecting horizontal slot 214, preventing the connecting sleeve 222 from being separated from the first sleeve 211; the user rotates the sleeve body 221, which can drive the connecting sleeve 222 to rotate, the unlocking inclined surface 2233 can be connected with the inner wall of the first sleeve 211, and further rotating the connecting sleeve 222, under the limitation of the inner wall of the first sleeve 211, the tenon body 2231 is pressed into the tenon slot until the tenon body 2231 is separated from the connecting horizontal slot 214; at this time, the user pulls the sleeve body 221 outward, the connecting sleeve 222 can be axially separated from the first sleeve 211, the sleeve body 221 can be taken out of the venous blood vessel, and the filter screen assembly 21 placement operation is completed; rotating the connecting sleeve 222, the tenon 223 can be popped out by the flat spring 224 and connected with the tenon slot 215; the user can feel obvious paragraph feeling and resistance of rotating the connecting sleeve 222, which makes the user confirm that the tenon body 2231 is separated from the connecting horizontal slot 214, and the axially arranged tenon slot 215 can prevent the tenon 223 from being connected with the connecting horizontal slot 214 and guide the connecting sleeve 222 to be axially separated from the first sleeve 211.

[0055] The above description is only the preferred embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A filter device for the inferior vena cava, characterized in that The filter screen unit is positioned in the inferior vena cava by the front positioning unit and the rear positioning unit, and the filter screen of the filter screen unit can be kept from being tilted during the implantation operation and can be smoothly taken out of the inferior vena cava blood vessel subsequently. The front positioning unit comprises front positioning branches, a push-pull strip and a front positioning sleeve, the front positioning branches and the push-pull strip are arranged in the front positioning sleeve, and the filter screen unit is arranged on the front positioning sleeve; the rear positioning unit comprises rear positioning branches, a rear positioning sleeve and a rear protection tube, the rear positioning branches and the rear positioning sleeve are arranged in the rear protection tube, and one end of the rear positioning branches and the rear positioning sleeve is connected; the front positioning branches can be pulled by the push-pull strip and then be accommodated into the front positioning sleeve, and the front positioning unit as a whole can pass through the filter screen unit and be taken out of the human body; the rear positioning branches can be pulled by the rear positioning sleeve and then be accommodated into the rear protection tube, and the rear positioning unit as a whole can be taken out of the blood vessel. The filter screen unit comprises a filter screen assembly and a filter screen push-pull sleeve; the filter screen assembly comprises a first sleeve, filter branches and a connecting horizontal groove, the connecting horizontal groove is circumferentially arranged on the sleeve wall of the first sleeve; the filter screen push-pull sleeve comprises a sleeve body, a connecting sleeve, a tenon and a flat spring, the connecting sleeve is connected with the sleeve body, the outer wall of the connecting sleeve is provided with a tenon groove, and the tenon and the flat spring are arranged on the tenon groove; the tenon can be inserted into the connecting horizontal groove and connected with the connecting horizontal groove, and the connecting sleeve is prevented from being separated from the first sleeve; one end of the flat spring is connected with the tenon, the other end of the flat spring is connected with the tenon groove, the flat spring is used for making the tenon pop out of the tenon groove and making the tenon keep connected with the connecting horizontal groove; the flat spring can provide axial support for the tenon; the tenon comprises a tenon body, the tenon body is provided with a locking plane and an unlocking inclined plane, the locking plane can abut against the connecting horizontal groove and prevent the tenon from being axially separated from the first sleeve; The filter screen assembly further comprises a clamping groove, the clamping groove is axially arranged on the inner wall of the first sleeve; the tenon can be popped out by the flat spring and connected with the clamping groove.

2. The filtering device for the inferior vena cava according to claim 1, characterized in that, One end of the front positioning branches and the push-pull strip is connected, and the other end of the push-pull strip is a free end.

3. The filtering device for the inferior vena cava according to claim 2, characterized in that, The front positioning branches are arranged in plurality and are circumferentially distributed on the push-pull strip along the center line of the push-pull strip.

4. The filter device for the inferior vena cava according to claim 3, characterized in that, The front positioning branches are elastic positioning branches, can be pushed out of the front positioning sleeve by the push-pull strip and radially expanded.

5. The filter device for the inferior vena cava according to claim 1, characterized in that, The push-pull strip is a steel wire rope.

6. The filter device for the inferior vena cava according to claim 1, characterized in that, The rear positioning branches are arranged in plurality and are circumferentially distributed on the end face of the rear positioning sleeve.

7. The filtering device for the inferior vena cava according to claim 6, characterized in that, The rear positioning branches are elastic positioning branches, can be pushed out of the rear protection tube by the rear positioning sleeve and radially expanded.

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