WO2014044209A1 - Stent system for preventing bone cement leakage and use thereof - Google Patents

Description

 Stent system for preventing bone cement leakage and its application

 The present invention relates to medical devices, and more particularly to devices for use in the treatment of vertebral destruction and vertebral compression fracture. In a first aspect, the invention relates to a stent system for preventing leakage of bone cement. In a second aspect, the invention relates to the use of a stent system in percutaneous kyphoplasty. Background technique

 Treatment of vertebral destruction and vertebral compression fractures usually involves percutaneous kyphoplasty (PKP) and percutaneous vertebroplasty (PVP). PVP is to inject the thin bone cement directly into the vertebral body through the puncture needle for treatment. However, due to the leakage of the spinal canal into the bone cement, the bone cement cannot be fully pressurized to expand the vertebral body and restore the height of the vertebral body. Fix the fractured vertebral body deformity. On the other hand, under PVP, the bone cement is still injected into the fractured vertebral body under relatively high pressure, and the bone cement has a low viscosity, so there is a risk of bone cement leaking out of the vertebral body after injection. In addition, PVP lacks an accurate estimate of the amount of bone cement injected before surgery, which further increases the risk of bone cement leakage. Compared with PVP, the clinical effects of PKP in clinical treatment of vertebral destruction and vertebral compression fracture caused by osteoporosis, multiple myeloma, metastatic bone tumor, invasive hemangioma and trauma have been recognized. It can significantly relieve pain and prevent further compression and destruction of the vertebral body in a short time, and restore the physiological stability of the spinal vertebral body to some extent.

PKP is developed on the basis of PVP. It is a percutaneous puncture. A trocar with a certain inner diameter is inserted into the vertebral body through the pedicle or root, and then lifted by an expansion device (such as a balloon or the like). The endplate of the fractured vertebral body collapses, restores the height and shape of the collapsed vertebral body, reduces the kyphosis deformity, and creates a bone cavity in the vertebral body, then exits the expansion device and reaches the bone cavity under low pressure. Injection of bone cement. PKP passes the ball before the bone cement is injected The expansion of the sac is sufficient to raise the fracture endplate of the vertebral body, reduce the vertebral fracture, restore the height, and correct the kyphosis. Moreover, in PKP, bone cement is injected into the bony cavity at a relatively low pressure. In addition, the injected bone cement can be more viscous, and the amount of bone cement injected can also be determined according to the expansion volume. Therefore, PKP greatly reduces the incidence of bone cement leakage into the vertebral body. Chinese Patent Application No. 200580041894.8 discloses a system and method for delivering a bone disease therapeutic agent. In an implementation, the first elongate member, the second elongate member, and the expandable structure provide a non-axial channel into the interior of the skeletal support structure. The second elongate member is configured to deliver a source of radiation to the interior of the bone support structure via the lumen of the first elongate member. Chinese Patent Application No. 0 281 776 3.0 discloses a system and method for treating bone in which an expandable body is sized to be inserted into the bone on the wire without entering the cannula, and the expandable body is in the sponge bone The medium undergoes expansion to compact the sponge bone. After retracting the inner body, the bone treatment device can be guided into the bone, for example, using an external body, or the material can be delivered into the bone. Chinese Patent Application No. 201010559537.3 discloses an expanded structure of an adjustable high pressure dilatation balloon comprising an inflatable balloon. The expandable structure of the adjustable high pressure dilatation balloon controls the longitudinal extension length of the inflatable balloon through an adjusting nut fixed at one end of the metal guide wire, thereby avoiding the phenomenon that the axial expansion before the expansion and expansion of the balloon precedes the lateral expansion. Improve the effectiveness of the surgery. Chinese Patent Application No. 201 1 10171046.6 discloses a vertebral body-expandable balloon catheter comprising: a catheter having a Y-connector attached to one end of the catheter and a balloon attached to the other end of the catheter. The balloon of the vertebral body-expandable balloon catheter can expand in a predetermined open-reset direction, thereby not increasing the degree of fracture damage of the vertebral body fracture site and avoiding causing re-fracture. Chinese Patent Application No. 200410086120.4 discloses a metal tennis vertebral body shaping device comprising: a vertebral body needle, a guide needle, a working sleeve, a working sleeve handle, a metal tennis ball, a metal tennis expansion and a recycling system. The metal tennis ball is fed into the vertebral body through the metal tennis expansion and recovery system, and the support ring at both ends can be restored to the original shape and generate a large expansion force, effectively expanding the compressed vertebral body, and then pulling the support The ring stretches the metal tennis ball into a slender shape and then withdraws from the vertebral body, and then fills the bone cement or other vertebral body reinforcing material. Chang Min et al. "Biological characteristics of 'lantern skeleton shape' memory alloy vertebroplasty frame"("Chinese Journal of Tissue Engineering Research and Clinical Rehabilitation", 2010, 35) discloses a method for the treatment of thoracolumbar vertebral compression fractures. Lantern skeleton shaped "memory alloy vertebral body forming frame. The "lantern skeleton" memory alloy vertebral body forming frame can be inserted into the vertebral pedicle in two directions, safely, uniformly expanded, and has sufficient complex tension and compressive support force, which combines the elastic fixed support of the early stent and the later stage. A biologically fixed support formed by the fusion of bone cement and the like into the stent and the vertebral body. However, a certain degree of bone cement leakage still occurs during kyphoplasty, which is mainly due to excessive pressure in the vertebral body, thin bone cement, improper timing and amount of injection, and defect of the posterior margin of the diseased vertebra. Caused by other reasons. Leakage of bone cement usually manifests as leakage of drainage vein, leakage of vertebral body edge and leakage of puncture needle channel. Among them, drainage venous leakage and vertebral edge leakage are the most common. Drainage venous leakage is mainly due to the large venous drainage vein and the rich venous return blood, which makes the bone cement particularly easy to enter the vein to the distal end, and then enter the pulmonary circulation, which will cause obstruction of the vena cava system and pulmonary embolism, causing local blood. Poor blood flow and hemoptysis. Leakage at the edge of the vertebral body is caused by the destruction of the vertebral malignant tumor and the integrity of the vertebral structure after the traumatic fracture, resulting in the high pressure injection of the colloidal cement leaking through the rupture of the vertebral cortex or cartilage plate to the contour of the vertebral body. outer. When the bone cement enters the spinal canal, especially close to the intervertebral foramen, it will cause compression of the nerve root, the dural sac and even the spinal cord, resulting in sustained and strong neurological compression symptoms, and the paravertebral leakage will cause the vertebral body. Pre-plant ganglion compression, leading to abnormal dysfunction of the chest and abdomen organs. Therefore, PKP will inevitably still have a certain degree of bone cement overflow or leakage during vertebral body formation, even if bone cement is injected under pressure during surgery. Therefore, there is a need for a device for effectively preventing bone cement leakage during kyphoplasty, and the following two conditions should be met: 1) effectively preventing or reducing bone cement leakage; 2) convenient operation and low cost. Summary of the invention

Based on the above ideas and requirements, the present invention provides a stent device that prevents leakage of bone cement. A stent system for preventing leakage of bone cement includes an inner sleeve, an outer sleeve, and a stent capable of opening to prevent leakage of cement, wherein the stent is positioned near the distal end of the inner sleeve and is crimped into the outer sleeve, and the inner sleeve The cartridge can be moved relative to the outer sleeve within the outer sleeve such that the stent is released from the outer sleeve by pushing the inner sleeve to open. In accordance with the present invention, the stent is a balloon-expandable stent that includes an expandable balloon that is directly crimped into the stent, the expandable balloon being inflated through the catheter through the catheter to expand the stent. In this case, the stent can be opened while the balloon is distracted, and then the balloon is withdrawn, and then the bone cement is filled with a bone cement filler. Alternatively, the stent is a self-expanding stent that is used in conjunction with a generalized kyphoplasty instrument. In this case, after using the expandable balloon to support the diseased vertebra, the outer cannula of the stent is placed in the cannula of the balloon, and the stent is placed into the distracted diseased vertebra by pushing the inner cannula. The bracket is automatically bounced, and then the inner and outer sleeves of the stent are withdrawn, and then the bone cement filler is placed in the bone cement filling device. Whether it is a balloon-expandable stent or a self-expanding stent, the head end of the bone cement filler is accurately placed inside the proximal end of the stent during bone cement filling, and then the bone cement is filled. According to an embodiment of the present invention, the stent is a stent graft comprising a stent portion composed of a stent rod and a coating portion sewn to the stent portion, the stent portion being formed by cutting, braiding or welding. The material of the coating portion and the stent portion of the stent graft may be a degradable material or a non-degradable material, wherein the material of the membrane may be a polymer material such as PE, PET or PTFE or a degradable material such as PLLA or PLGA; The material of the bracket can be 316L, nickel Metals such as titanium, cobalt and chromium, or degradable metals such as magnesium alloys and iron alloys, or polymer materials such as PE, PET, and PTFE, or degradable materials such as PLLA and PLGA. According to an embodiment of the invention, the stent is a separate dense mesh stent. The dense mesh support means that it forms a dense mesh, and the material thereof may be, for example, a degradable material or a non-degradable material as described above, or may be formed by cutting, weaving or welding. Preferably, the mesh density is 10~30/mm ² and the aperture is 10~1000μπι. In addition, the meshes distributed on the mesh scaffold are equally sized from the proximal end to the distal end, or gradually decrease in diameter from the proximal end to the distal end, or alternately distributed in different diameters from the proximal end to the distal end. This ensures that the bone cement has a controlled leakage rate, which not only improves the bonding strength of the bone cement to the vertebral body, but also prevents a large amount of leakage of the bone cement. According to an embodiment of the invention, the stent is made of a material having a shape memory effect. Preferably, the braided wire of the braided stent has a diameter of 30 to 150 μm. According to the invention, the stent is constructed in a regular shape or an irregular shape. For example, the shape may be a regular shape such as a cylindrical shape, a whole cone shape, a proximal end taper shape, or a distal end cylindrical shape, or may be an ellipsoid shape, a waist drum shape, a bell shape or the like. The size of the bracket preferably ranges from 10 to 30 mm in diameter and 10 to 30 mm in length, wherein in the integrally tapered bracket, the proximal tapered diameter is 2 to 6 mm, the distal tapered diameter is 10 to 30 mm, and the tapered portion is long. 10~30mm; in the proximal tapered, distal cylindrical bracket, the diameter of the cone is 2~6mm, the length of the tapered part is 2~8mm, and the diameter of the middle and distal cylindrical is 10~30mm. , the length is 10~30mm. According to an embodiment of the present invention, the stent portion of the stent graft is configured as a closed loop or an open loop structure as a whole, or a structure in which the proximal end is a closed loop and the distal end is a helix, or is configured as a proximal end and a distal end in a closed loop. The middle is a spiral structure. The spiral structure design can make the stent more easily deformed, so as to adapt to the complex shape of the vertebral body, the adhesion is better, and the filling effect of the bone cement is good, thereby increasing the binding force with the vertebral body. Preferably, the film portion is sewn to the stent rod at the proximal and distal ends of the stent portion such that When the stent is opened, the suture portion can be moved along the stent rod to accommodate the deformation of the stent when it is opened. According to an embodiment of the invention, the stitching points are 2-5. Preferably, the film portion is sewn to the closed end at the distal end to prevent bone cement from leaking from the distal end of the stent. Preferably, the stent is configured to be tapered at the proximal end. The proximal conical design can effectively reduce the leakage of bone cement. Preferably, the film portion has a hole, which can be obtained by selecting a film material having a hole density of 1 to 50 pieces/mm ² or by laser drilling on the dense film film, preferably, the hole diameter is 10 to 1000 μm. The hole density is 10~30/mm ² . Similarly, the pores distributed over the membrane portion are equally sized from the proximal end to the distal end, or gradually decrease in diameter from the proximal end to the distal end, or alternately spaced from the proximal end to the distal end. This design ensures a controlled leakage rate of the bone cement, which not only improves the bonding strength of the bone cement to the vertebral body, but also prevents a large amount of leakage of the bone cement. Preferably, the stent system further comprises a development marker disposed at the proximal or distal end of the stent or simultaneously at the proximal and distal ends of the stent to facilitate positioning of the stent in the diseased vertebra and accurate placement of the cement filler Into the proximal end of the stent. According to a second aspect of the present invention, there is provided the use of the stent system for preventing cement leakage of the present invention in percutaneous kyphoplasty. DRAWINGS

 The features and advantages of the present invention will be apparent from the description of the appended claims appended claims. In the picture:

 BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic illustration of a stent system of the present invention.

2 is a schematic illustration of a stent of an embodiment of the invention wherein the stent is a separate dense mesh stent. 3A-3F are schematic illustrations of various configurations of stents in accordance with an embodiment of the present invention, wherein the stent is a stent graft.

 4A-4H are schematic illustrations of various shapes of a stent of the present invention, wherein the stent is a stent graft. List of reference signs

 1. Inner sleeve 2, outer sleeve 3, bracket 4, film covering part

 Embodiments of the present invention are described below with reference to the drawings. For convenience of description, the terms "proximal" and "distal" are used in the present invention, wherein "proximal" refers to the end near the operating end, and "distal" refers to one that is farther from the operating end.

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Figure 1 shows a stent system of the present invention for preventing cement leakage in kyphoplasty. As shown in FIG. 1, the stent system comprises an inner sleeve 1, an outer sleeve 2 and a bracket 3, wherein the bracket 3 is located near the distal end of the inner sleeve 1 and is pressed into the outer sleeve 2, and the inner sleeve 1 can be opposite The outer sleeve 2 is moved within the outer sleeve 2, and the stent 3 can be released outside the outer sleeve 2 by pushing the inner sleeve 1. The stent 3 can be a balloon-expandable stent or a self-expanding stent (not shown). After the balloon-expandable stent is released, the stent can be expanded by a dilator through a catheter that is directly crimped into the stent. Open, the self-expanding stent is made of a material having a shape memory effect to automatically open after release. Alternatively, the stent 3 can be a stent graft or a separate mesh stent as shown in FIG. The stent graft includes a stent portion composed of a stent rod and a membrane sutured to the stent portion In part, the material may be a degradable material or a non-degradable material, wherein the material of the coating part may be a conventional polymer material such as PE, PET, PTFE or a degradable material such as PLLA or PLGA; Conventional metals such as 316L, nickel-titanium, and cobalt-rhodium, or degradable metals such as magnesium alloys and iron alloys, or conventional polymer materials such as PE, PET, and PTFE, or degradable materials such as PLLA and PLGA. The scaffolding portion of the dense mesh stent and the stent graft can be made by cutting, weaving or welding. In this example, the stent portion of the dense mesh stent or the stent graft is made of a braided wire material having a diameter of 30 to 150 μm. In this example, the covered portion of the stent graft has a hole, which can be obtained by selecting a coating material having a pore density of 1 to 50/mm ² , or by laser drilling on a dense coating, and the pore diameter is 10~1000μηι, the density of the holes is 10~30/mm ² . In addition, the pores distributed over the membrane portion are equally sized from the proximal end to the distal end, or gradually decrease in diameter from the proximal end to the distal end, or alternately spaced from the proximal end to the distal end. These also apply to the mesh of the compact mesh bracket. This design can ensure a controlled leakage rate of the bone cement, which not only improves the bonding strength of the bone cement to the vertebral body, but also prevents a large amount of leakage of the bone cement. The stent graft is a closed loop as a whole, as shown in FIG. 3A, or an open-loop structure as a whole, as shown in FIG. 3B-3D, or a closed loop at the proximal end and a spiral at the distal end, as shown in FIG. 3E, The proximal end and the distal end are closed loops with a spiral structure in the middle, as shown in Fig. 3F. The design of the spiral structure makes the stent graft more easily deformed, so as to adapt to the complex shape of the vertebral body, the adhesion is better, and the filling effect of the bone cement is also good, thereby increasing the binding force with the vertebral body. As shown in Figures 4A-4C, the shape of the stent graft can be a regular shape such as a cylindrical shape, a whole cone shape, and a proximal tapered distal end cylindrical shape. Alternatively, as shown in FIGS. 4D-4H, the shape of the stent graft may be other irregular shapes such as an ellipsoid shape, a waist drum shape, and a dumbbell shape. The overall tapered stent has a proximal tapered diameter of 2 to 6 mm, a distal tapered diameter of 10 to 30 mm, a tapered portion of 10 to 30 mm _{, and a} proximal tapered, distal cylindrical stent with a tapered shape. The diameter is 2~6mm, the length of the tapered part is 2~8mm, and the diameter of the middle and distal cylindrical is 10-30mm, length 10~30mm. In addition, the proximal end of the stent graft is tapered, which is designed to reduce bone cement leakage. Further, as shown in Figures 4A-4F, the film portion 4 is sewn at the distal end into a closed end to prevent bone cement from leaking from the distal end of the stent graft. In this example, the covering portion 4 of the stent graft is sutured on the stent rod at the proximal end and the distal end, and the suture point is 2 to 5, which ensures that the suture portion of the membrane portion 4 moves along the stent rod when the stent is opened, thereby adapting Deformation when the stent is opened. The stent 3 can also be provided with a development marker (not shown) either alone or simultaneously at the proximal or distal end to facilitate positioning of the stent 3 in the diseased vertebra and accurate placement of the cement filler into the proximal end of the stent. During surgery, for the balloon-expandable stent, the stent is distracted while the balloon is distracted, the balloon is withdrawn, and then the bone cement is filled with a bone cement filler; for the self-expanding stent system, the stent system In combination with a generalized kyphoplasty instrument, after using the dilatation balloon to open the diseased vertebra, put the outer cannula of the stent into the cannula of the dilatation balloon, and then push the stent into the distraction by pushing the inner cannula In the diseased vertebra, the stent automatically bounces off, then the cannula of the stent system is withdrawn, and then placed into the bone cement filler. Whether it is a balloon-expandable stent or a self-expanding stent, the filler tip is accurately placed inside the proximal end of the stent during bone cement filling, and then the bone cement is filled. Those skilled in the art will appreciate that the above description is merely exemplary. Numerous modifications and changes can be made to the invention without departing from the spirit and scope of the invention. For example, the stent system of the present invention has been described in detail above with reference to the embodiments, but the features of the embodiments may be used either singly or in combination, and these are also within the scope of the invention.

Claims

1. A stent system to prevent bone cement leakage, characterized in that the stent system includes an inner casing, an outer casing and an expandable stent to prevent bone cement leakage, wherein the stent is positioned near the distal end of the inner casing and is pressed within the outer sleeve, and the inner sleeve is movable within the outer sleeve relative to the outer sleeve, allowing the stent to be released outside the outer sleeve to expand by pushing on the inner sleeve. 2. The stent system of claim 1, wherein the stent is a balloon-expandable stent, which includes an expandable balloon directly pressed into the stent, and the expandable balloon is expanded by a dilator via a catheter to expand the stent. And. 3. The stent system of claim 1, wherein the stent is a self-expanding stent. 4. The stent system of any one of claims 1-3, wherein the stent is a covered stent or a separate dense mesh stent. 5. The stent system of any one of claims 1-3, wherein the stent is formed by cutting, weaving or welding. 6. The stent system of any one of claims 1-3, wherein the stent is made of a material with a shape memory effect. 7. The stent system of claim 4, wherein the covered stent includes a stent part composed of a stent rod and a covered part sewn to the stent part, and the stent part is configured to have a closed-loop or open-loop structure as a whole, or is configured to have a proximal end. A structure with a closed loop and a helix at the distal end, or a structure with a closed loop at the proximal and distal ends and a helix in the middle. 8. The stent system of claim 7, wherein the coating portion is sutured to the stent rod at the proximal and distal ends of the stent portion so that the suture portion can move along the stent rod when the stent is opened, to accommodate the deformation of the stent when it is opened. 9. The stent system of claim 7, wherein the covered portion is sutured into a closed end at the distal end to prevent bone cement from leaking from the distal end of the stent. 10. The stent system of any one of claims 1-3, wherein the stent is configured to be tapered at the proximal end. 1 1. The stent system of claim 7, wherein the membrane portion has holes. 12. The stent system of claim 1 1 , wherein the pore density is 1 to 50 pores/mm ² and the pore diameter is 10 to 1000 μm. 13. The stent system of claim 11, wherein the holes distributed on the coating part are of equal size from the proximal end to the distal end, or the diameter gradually decreases from the proximal end to the distal end, or the holes have different diameters from the proximal end to the distal end. Alternating distribution. 14. The stent system of claim 4, wherein the meshes distributed on the dense mesh stent are of equal size from the proximal end to the distal end, or the diameter gradually decreases from the proximal end to the distal end, or the meshes have different diameters from the proximal end to the distal end. The holes are alternately distributed. 15. The stent system of claim 4, wherein the density of the mesh is 1 to 50 pieces/mm ² and the pore diameter is 10 to 1000 μm. 16. The stent system of any one of claims 1-3, wherein the stent system further includes a development mark disposed at the proximal end or the distal end of the stent or at both the proximal and distal ends of the stent. 17. Application of the stent system for preventing bone cement leakage according to any one of claims 1 to 16 in percutaneous kyphoplasty.