Bone cement injection device for vertebral body shaping

Abstract

This invention discloses a bone cement injection device for vertebral body shaping, applicable to percutaneous balloon dilatation kyphoplasty. The device includes an outer cannula, a balloon, a fixation sleeve, a check plug, an injection cylinder, and an injection plunger. The neck of the balloon is opened and compressed to one end of the inner hole of the outer cannula by the fixation sleeve. An elastic check plug is located within the fixation sleeve, with a channel in its center connecting the balloon and the injection cylinder. During bone cement injection, the bone cement is first pushed to the check plug through the injection cylinder under high pressure, and then injected forward into the balloon through the injection suture. The compression from the injection suture ruptures any remaining pores in the bone cement, ensuring the structural strength of the hardened bone cement and preventing cracking. After the bone cement injection is complete, the check plug is axially compressed and radially expanded, thereby closing the injection suture and preventing bone cement from passing through the check plug, thus avoiding the surgical risks caused by bone cement spillage.

Description

Technical Field

[0001] This invention relates to the field of medical devices, and more particularly to a bone cement injection device for vertebral body shaping. Background Technology

[0002] Percutaneous vertebroplasty is an effective treatment for osteoporotic fractures (OVCF) in the elderly. By injecting bone cement into the affected vertebral body, the heat released after the bone cement is injected paralyzes the surrounding peripheral nerves, accelerates the dissipation of inflammatory factors, and relieves pain immediately. The solidified bone cement greatly enhances the bone hardness of the vertebral body, which is beneficial for the weight-bearing capacity of the injured vertebra. Due to its advantages such as being minimally invasive, having a fast recovery, and relieving pain immediately, it has been widely used in clinical practice.

[0003] Percutaneous vertebroplasty can be divided into three types depending on the surgical method: percutaneous puncture vertebroplasty (PVP), percutaneous balloon dilatation kyphoplasty (PKP), and bone-filled mesh bag percutaneous vertebroplasty. Among them, PKP is used for vertebral compression with a high degree of compression. An inflatable balloon is placed in the channel to effectively support the compressed bone, and then bone cement is filled in.

[0004] In existing technologies, bone cement is forcibly mixed using a pulling motion, and most commonly used devices employ this method. However, this method suffers from the problem of pores remaining within the bone cement. When bone cement is in its thin, low-viscosity state within a confined space, repeated pulling effectively forces the cement and air to mix by repeatedly ejecting it from a perforated, piston-like structure to achieve homogenization. This method easily creates closed pores within the liquid. As the viscosity of the bone cement rapidly increases, these pores remain within the cement and are retained in the injection space. The problem is that the position, shape, and size of these pores are uncontrollable, leading to significant unpredictability in the structural strength of the hardened bone cement. If multiple pores exist, connected in series along the direction of bone stress, stress concentration occurs at adjacent points of the closed pores, posing a significant risk of cracking. Directly injecting the mixed bone cement under pressure into the bone cavity also presents the problem of closed pores within the cement.

[0005] In addition, existing percutaneous balloon dilatation kyphoplasty techniques present difficulties in sealing the balloon after bone cement injection, and there is a risk of bone cement spillage and diffusion along the direction of the rupture into adjacent blood vessels and nerves, causing serious complications. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a bone cement injection device for vertebral body shaping, which can squeeze and break the pores inside the bone cement during injection and achieve self-sealing of the balloon after injection.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A bone cement injection device for vertebral body shaping, characterized in that it comprises:

[0009] The outer tube has a through first end and a through second end;

[0010] A balloon having a neck that is inserted into the first end of the outer sheath and an inflatable portion that is located outside the outer sheath;

[0011] A fixing sleeve, placed inside the neck of the balloon, is used to open the neck and squeeze the neck outward to fix it to the outer tube. The fixing sleeve has radially inwardly extending positioning edges at both ends of the inner hole of the fixing sleeve.

[0012] The check plug is a solid elastic structure. The check plug is placed inside a fixed sleeve and is axially limited by positioning at both ends. The end of the check plug away from the expansion part has a groove, and the end closer to the expansion part has an injection slit that connects to the groove.

[0013] The syringe, the front end of which can slide into the outer tube and is sealed within the groove of the check plug; and

[0014] The injection plunger is retractable and located inside the syringe barrel, with its front end extending out of the syringe barrel.

[0015] A further technical solution is that the outer wall of the fixing sleeve has a radially outward protrusion, and both ends of the protrusion are wedge-shaped surfaces that are inclined towards the middle of the axial direction.

[0016] A further technical solution is that there is a transition cavity between the settling tank and the injection seam. The transition cavity is conical, with its tip connected to the middle of the injection seam, and the diameter of the bottom surface of the cone is equal to the width of the injection seam.

[0017] A further technical solution is that the second end of the outer sleeve has a first fin extending radially outward; the outer ends of the injection cylinder and the injection push rod respectively have a second fin extending radially outward and a third fin.

[0018] A further technical solution is that, after the injection cylinder is inserted into the sink, there is a distance between the second fin and the first fin.

[0019] A further technical solution is that the check plug is made of silicone material.

[0020] A further technical solution is that the wall thickness of the balloon neck is not less than 0.3 mm.

[0021] A further technical solution is that an elastic piston head is fixed at the front end of the injection push rod, and both ends of the piston head are wedge-shaped surfaces that are inclined towards the middle of the axis.

[0022] The beneficial effects of adopting the above technical solution are as follows:

[0023] During bone cement injection, the cement is first pushed through the syringe to the check plug under high pressure, and then injected into the balloon through the injection seam. As the injection channel narrows, the cement compresses the seam, causing it to expand. The reaction force from the injection seam further compresses the cement, rupturing any remaining pores within the cement, thus ensuring the structural strength of the hardened cement and preventing cracking.

[0024] After the bone cement injection is completed, the injection plunger is inserted into the syringe, with the tip of the plunger extending from the syringe into the opened injection suture. This pushes the remaining bone cement in the injection suture into the balloon. After the injection plunger is withdrawn, the injection suture retracts and resets. On one hand, the bone cement in the balloon solidifies; on the other hand, the bone cement in the balloon exerts an outward compressive force on the inner end face of the check plug, causing the check plug to compress axially and expand radially. This closes the injection suture, preventing bone cement from passing through the check plug and avoiding the surgical risks caused by bone cement spillage. Attached Figure Description

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0026] Figure 1 This is a schematic diagram of the structure of the balloon before inflation in the device disclosed herein;

[0027] Figure 2 This is a schematic diagram of the balloon structure after inflation in the device disclosed herein;

[0028] Figure 3 This is a schematic cross-sectional view of the device disclosed herein (after balloon inflation);

[0029] Figure 4 This is a schematic diagram of the connection between the balloon and the outer sheath in the device disclosed herein;

[0030] Figure 5 This is a schematic diagram of the structure of the fixing sleeve in the device disclosed herein;

[0031] Figure 6 This is a cross-sectional structural diagram of the fixing sleeve in the device disclosed herein;

[0032] Figure 7 This is a schematic diagram of the structure of the device for stopping the backflow in this disclosure;

[0033] Figure 8 This is a schematic diagram of the longitudinal section structure of the device stop-return plug disclosed herein;

[0034] Figure 9This is a cross-sectional structural diagram of the device stop-return plug disclosed herein;

[0035] Figure 10 This is a diagram showing the device in use (the balloon expands to open the vertebral body). Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0038] like Figures 1-10 As shown, the bone cement injection device for vertebral body shaping disclosed herein can be used in percutaneous balloon dilatation kyphoplasty (PKP), including an outer cannula 1, a balloon 2, a fixation sleeve 3, a check plug 4, an injection cylinder 5, and an injection plunger 6.

[0039] The outer tube 1 has a through first end and a through second end, which initially fixes the balloon 2 during bone cement injection. After the bone cement injection is completed, it can be separated from the balloon 2 and removed.

[0040] The balloon 2 is an elastic body with a neck 201 that is inserted into the first end of the outer tube 1 and an expansion portion 202 that is placed outside the outer tube 1. The expansion portion 202 is a cavity for filling bone cement. During surgery, the expansion portion 202 needs to be filled to the vertebral body that needs to be reshaped and repositioned. After being filled with cement, the expansion portion 202 can expand and be shaped to effectively support the compressed bone at that location.

[0041] The fixing sleeve 3 is placed inside the neck 201 of the balloon 2 to expand the neck 201 and compress it outwards to fix it to the outer tube 1. Through the compression of the balloon 2 by the fixing sleeve 3, the neck 201 of the balloon 2 is restricted between the fixing sleeve 3 and the outer tube 1. The wall thickness of the neck 201 of the balloon 2 is not less than 0.3 mm to ensure that the wall thickness of the neck 201 of the balloon 2 has a certain amount of compression and will not be damaged due to the compression of the fixing sleeve 3.

[0042] The check plug 4 is a solid, elastic structure, preferably made of silicone. It has radially inwardly extending positioning edges 301 at both ends of the inner hole of the retaining sleeve 3. The check plug 4 is placed inside the retaining sleeve 3 and is axially limited by the positioning edges 301 at both ends, preventing the check plug 4 from dislodging from the retaining sleeve 3. The end of the check plug 4 away from the expansion part 202 has a groove 401, and the end closer to the expansion part 202 has an injection slit 402 communicating with the groove 401.

[0043] The front end of the syringe 5 can slide into the outer sleeve 1 and be inserted into the groove 401 of the check plug 4, and circumferentially presses against the inner wall of the groove 401, so that the outer wall of the front end of the syringe 5 and the groove 401 are circumferentially sealed. The injection push rod 6 is retractable inside the syringe 5, and its front end can extend out from inside the syringe 5.

[0044] During bone cement injection, the injection plunger 6 is withdrawn from the syringe 5. Under high pressure, the bone cement is first pushed through the syringe 5 to the check plug 4, and then injected forward into the balloon 2 through the injection seam 402. The balloon expands under the filling of the bone cement, forming an elliptical shape within the vertebral body and elevating and repositioning the vertebral body. During the injection process, the channel narrows as the bone cement passes through the injection seam 402, causing it to expand. The reaction force from the injection seam 402 further compresses the bone cement, rupturing any remaining pores within it, thus ensuring the structural strength of the hardened bone cement and preventing cracking.

[0045] After the bone cement injection is completed, the injection plunger 6 is inserted into the syringe 5, and the front end of the injection plunger 6 extends from the syringe 5 into the opened injection suture 402, pushing the bone cement remaining in the injection suture 402 into the balloon 2. After the injection plunger 6 is withdrawn, the injection suture 402 retracts and resets. On the one hand, the bone cement in the balloon 2 solidifies, and on the other hand, the bone cement in the balloon 2 exerts an outward compressive force on the inner end face of the check plug 4, causing the check plug 4 to be axially compressed and radially expanded, thereby closing the injection suture 402, thus preventing the bone cement from passing through the check plug 4 and avoiding the surgical risks caused by bone cement spillage.

[0046] Finally, after the bone cement has hardened, the outer cannula 1, syringe 5, and injection plunger 6 are separated from the balloon 2 and removed. The inflated balloon 2 and the front end of the outer cannula 1 form a cornered limiting area. Pulling the outer cannula 1 outward, the bone in the limiting area obstructs the balloon 2, preventing the balloon 2 from retracting along with it. This allows the outer cannula 1 and balloon 2 to be separated and the outer cannula 1, syringe 5, and injection plunger 6 to be removed. The balloon 2, fixation sleeve 3, and check plug 4 remain inside the body.

[0047] In the bone cement injection device for vertebral body shaping disclosed herein, the second end of the outer sleeve 1 has a first fin 101 extending radially outward, and the outer ends of the injection cylinder 5 and the injection push rod 6 have a second fin 501 and a third fin 601 extending radially outward, respectively. Due to the arrangement of the first fin 101, the second fin 501, and the third fin 601, after the bone cement injection is completed, pulling the outer sleeve 1 outward can simultaneously remove the outer sleeve 1, the injection cylinder 5, and the injection push rod 6, making the operation more convenient.

[0048] Furthermore, after the syringe 5 is inserted into the sink 401, there is a distance between the second fin 501 and the first fin 101. This allows the outer tube 1 to separate from the balloon 2 first, and then the syringe 5 to separate from the check plug 4, preventing the outer tube 1 and the syringe 5 from separating from the balloon 2 at the same time, which would cause excessive stress on the neck 201 of the balloon 2.

[0049] In the bone cement injection device for vertebral body shaping disclosed herein, the outer wall of the fixing sleeve 3 has a radially outward protrusion 302. The protrusion 302 reliably compresses the neck 201 of the balloon 2, causing significant compression deformation of the portion of the balloon 2 neck 201 corresponding to the protrusion 302. This results in greater friction between the neck 201 and the outer sleeve 1, ensuring a stable connection between the balloon 2 and the outer sleeve 1 during cement injection. Furthermore, both ends of the protrusion 302 are wedge-shaped surfaces axially inclined towards the center. The inner wedge-shaped surface facilitates the insertion of the fixing sleeve 3 into the balloon 2, while the outer conical surface facilitates the insertion of the balloon 2 and fixing sleeve 3 into the outer sleeve 1 after assembly.

[0050] In addition, to ensure the stability of the connection between the fixing sleeve 3 and the neck 201 of the balloon 2, besides using the elasticity of the balloon 2 to open the neck 201 of the balloon 2 with the fixing sleeve 3, the neck 201 of the balloon 2 can also be further bonded and fixed to the fixing sleeve 3.

[0051] In the bone cement injection device for vertebral body shaping disclosed herein, a transition cavity 403 is provided between the sink 401 and the injection slit 402. The transition cavity 403 is conical, with its tip connected to the middle of the injection slit 402. The diameter of the bottom surface of the cone is equal to the width of the injection slit 402. The transition cavity 403 serves to guide the bone cement from the outer sleeve 1 into the injection slit 402. After the bone cement injection is completed, the bone cement remaining in the transition cavity 403 hardens to form a cone. When the injection push rod 6 is pushed forward, the cone can be used to smoothly enter the opened injection slit 402 and push all the bone cement remaining in the injection slit 402 into the balloon 2, which is conducive to the later closure of the injection slit 402.

[0052] In the bone cement injection device for vertebral body shaping disclosed herein, an elastic piston head (not shown) is fixed to the front end of the injection plunger 6. The annular sidewall of the piston head is in contact with the inner wall of the injection cylinder 5. When the injection plunger 6 is advanced forward, all the bone cement adhering to the inner wall of the injection cylinder 5 can be pushed into the balloon 2, reducing the difference between the amount of bone cement stirred and the amount injected, making the surgical operation more accurate. Moreover, both ends of the piston head in the axial direction are wedge-shaped surfaces, both inclined towards the middle of the axial direction. The wedge-shaped surface design facilitates the entry of the piston head from the first and second ends of the injection cylinder 5.

[0053] The above are merely preferred embodiments of the present invention. Any simple modifications, variations, and equivalent substitutions made by any person based on the content of the present invention shall fall within the protection scope of the present invention.

Claims

1. A bone cement injection device for vertebral body shaping, characterized in that... ,include: The outer tube (1) has a through first end and a through second end; The balloon (2) has a neck (201) inserted into the first end of the outer tube (1) and an inflatable portion (202) placed outside the outer tube (1). The fixing sleeve (3) is placed inside the neck (201) of the balloon (2) to open the neck (201) and squeeze the neck (201) outward so that it is fixed to the outer tube (1). The fixing sleeve (3) has a positioning edge (301) extending radially inward at both ends of the inner hole. The outer wall of the fixing sleeve (3) has a circumference of radially outward protrusion (302). Both ends of the axial direction of the protrusion (302) are wedge-shaped surfaces, and both are inclined towards the middle of the axial direction. The check plug (4) is a solid elastic structure. The check plug (4) is placed in the fixed sleeve (3) and is axially limited by the positioning at both ends (301). The end of the check plug (4) away from the expansion part (202) has a groove (401) and the end near the expansion part (202) has an injection slit (402) that connects to the groove (401). There is also a transition cavity (403) between the groove (401) and the injection slit (402). The transition cavity (403) is conical, and its tip connects to the middle of the injection slit (402). The diameter of the bottom surface of the cone is equal to the width of the injection slit (402). The syringe (5) has its front end slidably inserted into the outer sleeve (1) and sealed into the groove (401) of the check plug (4); and The injection plunger (6) is retractable and located inside the injection cylinder (5), with its front end extending out from inside the injection cylinder (5).

2. The apparatus according to claim 1, characterized in that... The outer tube (1) has a first fin (101) extending radially outward at its second end; the outer ends of the injection cylinder (5) and the injection push rod (6) have a second fin (501) and a third fin (601) extending radially outward, respectively.

3. The apparatus according to claim 2, characterized in that... After the injection cylinder (5) is inserted into the sink (401), there is a distance between the second fin plate (501) and the first fin plate (101).

4. The apparatus according to claim 1, characterized in that... The check plug (4) is made of silicone.

5. The apparatus according to claim 1, characterized in that... The wall thickness of the neck (201) of the balloon (2) is not less than 0.3 mm.

6. The apparatus according to claim 1, characterized in that... The front end of the injection push rod (6) is fixed with an elastic piston head. Both ends of the piston head are wedge-shaped surfaces and are inclined towards the middle of the axis.

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