A posterior lumbar zero-profile fusion system and its use method

Abstract

The present invention discloses a posterior lumbar zero-profile fusion system and a method for using the same. The fusion system includes a fusion device and an impactor; the impactor includes a connecting seat, which is detachably connected to the fusion device; at least two inclined locking holes are provided on the front side of the fusion device; the axial height of the connecting seat is more than 1.5 cm; the connecting seat is provided with at least two inclined through-channels, and the outlet end of each channel corresponds to a locking hole; the angle between the channel axis and the connecting seat axis is 30 to 35 degrees. According to the present invention, it is only necessary to retract nerve tissues such as nerve roots and dura mater sacs once, and after the fusion device is placed between vertebrae by the impactor, the connecting seat is not directly removed. In the process of screwing in the locking screw, the locking screw and the screwdriver are completely in the connecting seat and the fusion device, and do not contact the surrounding nerve tissue to avoid damaging the surrounding nerve tissue of the vertebrae. Only one posterior spinal canal incision is required, which can greatly reduce surgical costs, surgical risks, surgical trauma and surgical time.

Description

Technical Field

[0001] The present invention relates to the technical field of posterior lumbar implantation, and in particular to a posterior lumbar zero-profile fusion device system and a method for using the same. Background Art

[0002] The spine is a bone structure composed of one vertebral body, two pedicles, two lamina, two transverse processes, four articular processes and one spinous process, and is divided into cervical vertebrae, thoracic vertebrae, lumbar vertebrae, sacral vertebrae and coccyx. Lumbar diseases can be caused by bad habits or momentary inappropriate behavior. At present, with the frequent occurrence of spinal diseases, the treatment methods for the spine are becoming more and more targeted. Lumbar fusion surgery is currently the main means of treating lumbar diseases. Lumbar fusion cages, as important implants in lumbar intervertebral interface fusion technology, play an increasingly important role. Lumbar fusion cages are generally divided into fusion cages used in the anterior route and fusion cages used in the posterior route. Due to the large operating space of the anterior lumbar spine, the risk of using anterior fusion cages is smaller than that of posterior fusion cages. At present, anterior fusion cages have achieved good results but require two surgical incisions. The operation is complicated, traumatic and risky. For this purpose, the industry has developed posterior fusion devices, such as Chinese utility model CN203693843U which discloses a posterior lumbar intervertebral fixation fusion device, and Chinese utility model CN209316161U which discloses a zero-profile posterior lumbar fusion device.

[0003] The surgical process of posterior lumbar fusion device placement is as follows: the transverse diameter of the spinal canal is about 2.5 cm, with a dura mater sac inside and nerve roots on both sides. When inserting the fusion device, the nerve roots and dura mater sac on one side must first be pulled toward the opposite side to expose the intervertebral disc. The fusion device is then inserted after the protruding intervertebral disc is removed. Furthermore, the top of the inserted fusion device (i.e. the front top of the fusion device) must be about 2-4 mm deeper than the posterior edge of the vertebral body.

[0004] After the prior art posterior lumbar fusion devices (including but not limited to those disclosed in the above two utility models) are inserted into the fusion device between the vertebrae using an inserter, after the inserter is withdrawn, the nerve roots and the dura mater sac return to their original positions, covering or partially covering the top of the fusion device, making the top almost impossible to directly observe, and even more impossible to screw in a locking screw at the top of the fusion device. Currently, the existing posterior fusion devices are not operable in actual clinical practice. The reason is that the nerve roots and the dura mater sac can only be retracted to the midline of the spinal canal, which is about 1.3 cm. Within this width, a fusion device with a width of 1 cm is inserted. In order to screw in the locking screw, the nerve roots and the dura mater sac need to be retracted again, which will cause the nerve roots to be damaged by excessive or frequent retraction. In addition, screwing in the locking screw is very likely to cause wear and damage to the surrounding nerve tissue such as the nerve roots and the dura mater sac, which is very risky.

[0005] Even if the fusion device disclosed in Chinese utility model CN209316161U uses a fixing body with a locking hole having a guiding function, in actual clinical surgery for posterior vertebral insertion, since the fixing body is fixedly connected to the fusion device body and inserted into the vertebra, the top end of the fixing body does not at least extend beyond the posterior edge of the vertebral body after insertion. As a result, the locking hole cannot be directly seen, and the locking nail cannot be screwed in. Even if nerve tissue such as nerve roots and dura mater can be retracted in some cases to partially expose the top end of the fusion device to see the locking hole, only the locking hole can be seen. When screwing a locking nail of a certain length into the vertebral body at an angle through the locking hole, not only is there a high risk of the threads on the outer peripheral surface of the locking hole contacting and damaging nerve tissue such as nerve roots and dura mater, but the oblique insertion of the locking nail requires a larger operating space for retracting nerve tissue such as nerve roots and dura mater than vertical insertion, which results in greater surgical risks.

[0006] Although there are zero-profile posterior lumbar fusion devices available, due to the complex structure of the posterior lumbar spine and the small operating space, the current zero-profile posterior lumbar fusion devices are not very maneuverable in specific applications. They require multiple retractions of nerve roots, dura mater sac and other neural tissues, and the tilted insertion process of the locking screws carries a high risk of damaging nerve roots, dura mater sac and other neural tissues. Therefore, the actual application of the existing zero-profile posterior lumbar fusion devices in clinical surgery is still very challenging and involves surgical risks. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides a posterior lumbar zero-profile fusion system and a method for using the same.

[0008] The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0009] A posterior lumbar zero-profile fusion system comprises a fusion device and an impactor; the impactor comprises a connecting seat which is detachably connected to the fusion device; at least two inclined locking holes are provided on the front side of the fusion device; the axial height of the connecting seat is greater than 1.5 cm; the connecting seat is provided with at least two inclined through-channels, the outlet end of each channel corresponding to one of the locking holes; the angle between the channel axis and the connecting seat axis is 30-35°.

[0010] As a preferred embodiment of the posterior lumbar zero-profile fusion system provided by the present invention, the locking hole is coaxially arranged with the channel.

[0011] As a preferred embodiment of the posterior lumbar zero-profile fusion system provided by the present invention, the axial height of the connecting seat is 1.5-2.0 cm.

[0012] As a preferred embodiment of the posterior lumbar zero-profile fusion system provided by the present invention, the detachable connection between the fusion device and the connecting seat is a threaded connection structure or a snap-on connection structure.

[0013] As a preferred embodiment of the posterior lumbar zero-profile fusion system provided by the present invention, the threaded connection structure includes a threaded hole arranged at the top of the front side of the fusion device and a threaded head arranged on the connecting seat, and the threaded head cooperates with the threaded hole.

[0014] As a preferred embodiment of the posterior lumbar zero-profile fusion system provided by the present invention, the entrance end of the channel is arranged at the front top of the connecting seat.

[0015] As a preferred embodiment of the posterior lumbar zero-profile fusion system provided by the present invention, the entrance end of the channel is arranged on the front side of the connecting seat.

[0016] As a preferred embodiment of the posterior lumbar zero-profile fusion system provided by the present invention, the fusion device includes a fusion device body and an artificial bone filling hole penetrating the fusion device body.

[0017] As a preferred embodiment of the posterior lumbar zero-profile fusion device system provided by the present invention, a corrugated structure is provided on the outer surface of the fusion device body.

[0018] As a preferred embodiment of the posterior lumbar zero-profile fusion system provided by the present invention, the two locking holes are arranged at two ends of the front side of the fusion device; and the inclination directions of the two locking holes are opposite.

[0019] A method for using a posterior lumbar zero-profile fusion device system comprises the following steps: after completing posterior lumbar spinal canal decompression and discectomy surgery, the fusion device and the connecting seat connected to each other are placed between the vertebral bodies from back to front through the spinal canal via an inserter body, locking screws of a desired length are selected and loaded into the channels, the locking screws are screwed out of the locking holes and into the vertebral bodies to lock the locking screws to the front side of the fusion device and the vertebral body, thereby locking the fusion device and the vertebral body; after all the locking screws are screwed in, the connecting seat is detached from the fusion device via the inserter body.

[0020] The present invention has the following beneficial effects:

[0021] The present invention provides a connector seat, removably connected to the fusion device, with an axial height of at least 1.5 cm. The connector seat is provided with at least two obliquely extending channels, each channel outlet corresponding to a locking hole. The angle between the channel axis and the connector seat axis is 30-35 degrees. With this design, after completing posterior lumbar spinal decompression and discectomy surgery, the interconnected fusion device and connector seat are inserted from back to front through the spinal canal into the intervertebral body. A locking screw of the desired length is then inserted into the channel using an elastic screwdriver and screwed out through the locking hole into the vertebral body, locking the screw into the front of the fusion device and into the vertebral body. Finally, the driver is removed along with the connector seat.

[0022] By using the fusion device system of the present invention, it is only necessary to retract nerve tissues such as nerve roots and dura mater sac at one time. After the fusion device is placed between vertebrae by the driver, the connecting seat is not directly removed. A locking nail of a suitable length is selected according to the actual penetration depth, and then inserted into an inclined channel in the connecting seat, into the locking hole, and then screwed into the vertebrae. In this way, the axial height of the connecting seat is more than 1.5 cm, and the angle between the axis of the channel and the axis of the connecting seat is 30-35 degrees. Then, the entrance end of the inclined channel is completely higher than the nerve tissues such as nerve roots and dura mater sac, and the inclined channel is equivalent to a The role of the catheter is to protect the nerve tissue outside the fusion device and around the connecting seat. During the process of screwing in the locking screw, the locking screw and the screwdriver are completely inserted into the connecting seat and the fusion device without contacting the surrounding nerve tissue, thereby avoiding or even eliminating the accidental damage to the nerve tissue around the vertebral body during the process of screwing in the locking screw. At the same time, the posterior lumbar zero-notch fusion system of the present invention only requires one posterior spinal incision when used, and does not require another anterior spinal incision, which can greatly reduce surgical costs, surgical risks, surgical trauma and surgical time, and has good social and economic benefits.

[0023] The inclined channel provided in the connecting seat of the present invention is not only used to accommodate and limit the entire or most of the locking pins and the entry and exit paths of the screwdriver to avoid the problem that the locking pins of the existing fusion device only have an introduction hole at the head, which causes shaking and deviation from the preset tilt angle when the locking pins begin to be screwed in, but also the angle between the channel axis and the connecting seat axis is set to 30-35 degrees, so that the length of the channel is long enough to accommodate locking pins of different lengths, making it convenient to select locking pins of appropriate length according to the condition of the vertebral body, further improving the locking stability of the fusion device and the vertebral bodies on both sides, and solving the problem that the length of the locking pins cannot be flexibly adjusted after the existing fusion device with built-in locking pins is placed between the vertebrae. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the structure of the fusion device system of the present invention;

[0025] Figure 2 is an exploded schematic diagram of the fusion cage system of the present invention;

[0026] Figure 3 for Figure 1 Cross-sectional view at AA in the middle;

[0027] Figure 4 This is a flow chart of a method for using the fusion device system of the present invention;

[0028] Figure 5 Schematic diagram of the use process of the fusion device system of the present invention. DETAILED DESCRIPTION

[0029] The technical solutions of the present invention are further described in detail below in conjunction with specific embodiments and drawings. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0030] Please refer to Figure 1-3 The present invention provides a posterior lumbar zero-profile fusion device system, which includes a fusion device 1 and an impactor, wherein the impactor is used to place the fusion device 1 between the vertebral bodies from the posterior lumbar spine. Specifically, the impactor includes an impactor body (not shown in the figure) and a connecting seat 2 connected to the impactor body, wherein the connecting seat 2 is detachably connected to the fusion device 1, and the impactor body is used to place the connecting seat 2 and the fusion device 1 together between the vertebral bodies and to detach the connecting seat 2 from the fusion device 1 to remove the connecting seat 2 from the vertebral bodies. At least two inclined locking holes 11 are provided on the front side of the fusion device 1, and the locking holes 11 are used for the locking nails 3 to pass through so as to be screwed into the vertebral body and to be fixed on the fusion device 1. The axial height h of the connecting seat 2 is more than 1.5 cm; the connecting seat 2 is provided with at least two inclined through-channels 21, and the outlet end of each channel 21 corresponds to one of the locking holes 11. When the locking nail 3 is inserted into the channel 21, it can directly enter and pass through the locking hole 11 along the channel 21; the angle a between the axis of the channel 21 and the axis of the connecting seat 2 is 30~35°. Such a design not only ensures that the length of the channel 21 is long enough, but also ensures that the locking nail 3 is screwed into the vertebral body at an effective inclined angle, so that the connection between the fusion device 1 and the vertebral body is more stable.

[0031] In the present invention, the locking hole 11 is coaxially arranged with the channel 21. This design facilitates the locking pin 3 to smoothly and non-deflectively enter and pass through the locking hole 11 along the channel 21, allowing the locking pin 3 to be effectively screwed into the vertebral body at a predetermined inclination angle. It is also understood that the inclination angle of the locking hole 11 relative to the axis of the fusion cage 1 is the same as the inclination angle of the channel 21 relative to the axis of the connector 2.

[0032] In the present invention, the axial height of the connecting seat 2 is 1.5~2.0 cm. The height design is too short, similar to the introduction hole set on the head of the existing posterior fusion device 1, which makes it difficult to effectively expose the locking hole 11 and difficult to protect the posterior nerve tissue. The height design is too long, which is not conducive to operation.

[0033] In the present invention, the detachable connection between the fusion device 1 and the connecting seat 2 is a threaded connection structure or a snap-on connection structure. Specifically, the threaded connection structure includes a threaded hole 12 provided at the top front side of the fusion device 1 and a threaded head provided on the connecting seat 2, and the threaded head cooperates with the threaded hole 12. In specific implementation, the threaded head of the connecting seat 2 can be driven out of the threaded hole 12 by rotating the main body of the impactor, thereby realizing the detachment of the connecting seat 2 from the fusion device 1. It should be noted that the main body of the impactor is an existing conventional component, which serves to place the connecting seat 2 and the fusion device 1 between the vertebral bodies and to detach the connecting seat 2 from the fusion device 1. It is worth noting that the main body of the impactor and the connecting seat 2 can be an integrated connection or an independent connection. The independent connection here means that the main body of the impactor and the connecting seat 2 are independent of each other. When the main body of the impactor is required to act on the connecting seat 2, the main body of the impactor is connected to the connecting seat 2. Furthermore, the driver body is detachably connected to the connecting seat 2 via a connecting piece, so that the driver body drives the connecting seat 2 to move and rotate, etc. through the connecting piece.

[0034] In certain embodiments of the present invention, the entrance end 211 of the channel 21 is disposed at the front top of the connector 2. In other embodiments, the entrance end 211 of the channel 21 is disposed at the front side of the connector 2. Since the axial height h of the connector 2 is greater than 1.5 cm, and the angle a between the axis of the channel 21 and the axis of the connector 2 is 30-35 degrees, the entrance end 211 of the inclined channel 21, whether designed at the front top or the side of the connector 2, is completely higher than nerve tissue such as nerve roots and the dural sac. The inclined channel 21 acts as a conduit, protecting the nerve tissue outside the fusion cage 1 and around the connector 2. During the process of screwing in the locking screw 3, the locking screw 3 and the screwdriver are completely within the connector 2 and the fusion cage 1, without contacting the surrounding nerve tissue, thereby avoiding or even eliminating the possibility of accidental damage to the surrounding nerve tissue of the vertebral body during the screwing in of the locking screw 3.

[0035] In the present invention, the fusion device 1 includes a fusion device body 13 and an artificial bone filling hole 14 extending through the fusion device body 13. Specifically, artificial bone material can be poured into the artificial bone filling hole 14, allowing the artificial bone to integrate with the lumbar vertebrae and accelerate postoperative recovery. Specifically, in this embodiment of the present application, the artificial bone filling hole 14 is arranged along the fusion device 1 toward the vertebral body and extends through both sides thereof, allowing the artificial bone material to directly contact the two vertebrae.

[0036] In the present invention, a corrugated structure 15 is provided on the outer surface of the fusion device body 13. The corrugated structure 15 protrudes from the outer surface of the fusion device 1 to prevent the fusion device 1 from sliding relative to the vertebrae during use. It is understood that the corrugated structure 15 can also be provided as other similar structures to increase friction.

[0037] In the present invention, two locking holes 11 are provided at the two ends of the front side of the fusion cage 1; the two locking holes 11 are inclined in opposite directions. It is understood that more than two locking holes 11 can be provided according to actual needs to enhance the locking connection stability between the fusion cage 1 and the vertebral body.

[0038] like Figure 4 、 5 As shown, the process of using the present invention is as follows:

[0039] After the posterior spinal decompression and discectomy are completed, the fusion device 1 and the connecting seat 2 connected to each other are placed through the spinal canal from back to front into the intervertebral body (such as Figure 5 As shown in (a), select the locking nail 3 of the required length and install it into the channel 21 (as shown in Figure 5 (b)), and then use an elastic screwdriver to screw the locking nail 3 out of the locking hole 11 and into the vertebral body to lock the locking nail 3 in the front side of the fusion cage 1 and the vertebral body to complete the locking of the fusion cage 1 and the vertebral body. After all the locking nails 3 are screwed in (as shown in FIG. Figure 5 As shown in (c), the connecting seat 2 is detached from the fusion device 1 by the main body of the driver, and the connecting seat 2 is removed together with the driver (as shown in Figure 5 (d)).

[0040] By using the fusion device system of the present invention, it is only necessary to retract nerve tissues such as nerve roots and dural sacs at one time. After the fusion device 1 is placed between the vertebrae by the driver, the connecting seat 2 is not directly removed. A locking nail 3 of a suitable length is selected according to the actual penetration depth, and then inserted into an inclined channel 21 in the connecting seat 2, enters the locking hole 11, and then screwed into the vertebral body. In this way, the axial height of the connecting seat 2 is more than 1.5 cm, and the angle a between the axis of the channel 21 and the axis of the connecting seat 2 is 30-35 degrees. Then, the entrance end 211 of the inclined channel 21 is completely higher than the nerve tissues such as nerve roots and dural sacs, and the inclined channel 21 acts as a catheter to protect the nerve tissue outside the fusion device 1 and around the connecting seat 2. During the process of screwing in the locking screw 3, the locking screw 3 and the screwdriver are completely in the connecting seat 2 and the fusion device 1, and do not come into contact with the surrounding nerve tissue, so as to avoid or even eliminate the accidental damage to the nerve tissue around the vertebral body during the process of screwing in the locking screw 3. At the same time, the posterior lumbar zero-notch fusion device system of the present invention only requires one posterior spinal canal incision when used, and does not need to make another anterior spinal canal incision, which can greatly reduce surgical costs, surgical risks, surgical trauma and surgical time, and has better social and economic benefits.

[0041] The inclined channel 21 provided in the connecting seat 2 of the present invention is not only used to accommodate and limit the entire or most of the locking pins 3 and the entry and exit paths of the screwdriver to avoid the problem that the locking pins 3 of the existing fusion device 1 only have an introduction hole on the head, which causes shaking and deviation from the preset tilt angle when the locking pins 3 begin to be screwed in, but also sets the angle a between the axis of the channel 21 and the axis of the connecting seat 2 to 30~35°, so that the length of the channel 21 is long enough to accommodate locking pins 3 of different lengths, making it convenient to select the locking pins 3 of appropriate length according to the vertebral condition, further improving the locking stability of the fusion device 1 and the vertebrae on both sides, and solving the problem that the length of the locking pins 3 cannot be flexibly adjusted after the existing fusion device 1 with the built-in locking pins 3 is placed between the vertebrae.

[0042] The above-mentioned embodiments merely express the implementation methods of the present invention. The description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. Any technical solution obtained in the form of equivalent replacement or equivalent transformation should fall within the scope of protection of the present invention.

Claims

1. A posterior lumbar zero-profile fusion system comprising a fusion device and an impactor; the impactor comprises a connecting seat detachably connected to the fusion device; the front side of the fusion device is provided with at least two inclined locking holes; characterized in that: The axial height of the connecting base is greater than 1.5 cm; the connecting base is provided with at least two obliquely extending passages, the outlet end of each passage corresponding to a locking hole, and the locking pin can be directly inserted into the passage and pass through the locking hole; the angle between the axis of the passage and the axis of the connecting base is 30-35 degrees; The entrance end of the inclined channel is higher than the nerve tissue. During the process of screwing in the locking screw, the locking screw and the screwdriver are completely inserted into the connector and the fusion device without contacting the surrounding nerve tissue. The outer surface of the fusion device is provided with a structure for increasing friction, so as to prevent the fusion device from sliding relative to the vertebrae when in use.

2. The posterior lumbar zero-profile fusion cage system according to claim 1, characterized in that: The locking hole is coaxially arranged with the channel.

3. The posterior lumbar zero-profile fusion system according to claim 1, characterized in that: The axial height of the connecting seat is 1.5-2.0 cm.

4. The posterior lumbar zero-profile fusion cage system according to claim 1, characterized in that: The detachable connection between the fusion device and the connecting seat is a threaded connection structure or a snap-on connection structure.

5. The posterior lumbar zero-profile fusion cage system according to claim 4, characterized in that: The threaded connection structure includes a threaded hole provided at the top of the front side of the fusion device and a threaded head provided on the connection seat, and the threaded head cooperates with the threaded hole.

6. The posterior lumbar zero-profile fusion cage system according to claim 1, characterized in that: The inlet end of the channel is arranged at the front top of the connecting seat.

7. The posterior lumbar zero-profile fusion cage system according to claim 1, characterized in that: The inlet end of the channel is arranged on the front side of the connecting seat.

8. The posterior lumbar zero-profile fusion cage system according to claim 1, characterized in that: The fusion device comprises a fusion device body and an artificial bone filling hole penetrating the fusion device body.

9. The posterior lumbar zero-profile fusion cage system according to claim 1, characterized in that: The two locking holes are arranged at two ends of the front side of the fusion device; and the inclination directions of the two locking holes are opposite.

Images