Guide device and customization method for anterior cervical retrograde pedicle screw plate

Abstract

The present invention discloses a guide device for anterior retrograde pedicle screw plate of cervical spine and a customization method thereof. The guide device comprises a base plate and a screw channel, the base plate is provided with an embedding groove for inserting the steel plate, and the edge is provided with a first through hole for passing the Kirschner wire; the screw channel is tubular and there are two pairs of screw channels, the screw channels are fixed to the back of the base plate, and the same pair of screw channels are inclined in a V shape. The steps of the customization method are: 1) constructing a base plate matching the steel plate; 2) collecting the original data of the cervical spine, establishing a three-dimensional vertebral model, and virtually installing the steel plate; 3) performing a three-dimensional analysis of the pedicle screw channel of the fixed steel plate; 4) extracting the partial contour of the connection between the required fixed vertebral body and the transverse processes on both sides, constructing a positioning plate, and then constructing the screw channel, and establishing a virtual guide device; 5) 3D printing the guide device. The present invention has the advantages of precision, safety, and low radiation in intraoperative use.

Description

Technical Field

[0001] The invention relates to the field of medical technology, and in particular to a guide device for anterior cervical retrograde pedicle screw plates, and a method for customizing the guide device. Background Art

[0002] Compared with the posterior approach, the anterior cervical approach has the characteristics of less surgical trauma, convenient lesion treatment, and fewer complications. Therefore, titanium plate combined with vertebral screw fixation under the anterior cervical approach is currently a widely used surgical method for the treatment of cervical spine diseases. However, for cases of severe damage to cervical stability such as three-column injury and multiple subtotal vertebral resection, the strength of simple anterior titanium plate combined with vertebral screw fixation is limited, and additional posterior fixation is often required, which not only significantly increases hospitalization time and treatment costs, but also significantly increases surgical trauma and complication rates. Therefore, how to achieve strong and effective internal fixation under a single anterior cervical approach has always been a hot topic in the field of spinal surgery. Anterior cervical pedicle screw fixation is a three-column fixation method, and biomechanical studies have confirmed that this fixation method can provide reliable fixation strength.

[0003] In the prior art, patent document CN209236346U discloses a fixation device used in anterior cervical fixation surgery. Figure 1 As shown, the core component of the fixation device is a cervical anterior retrograde pedicle screw steel plate 1 (corresponding to the connecting plate in the patent document, hereinafter referred to as the steel plate) for fixing on the cervical spine, and nail holes 2 are opened at both ends of the steel plate 1, and the nail holes 2 are long holes and can pass two pedicle screws at the same time; the steel plate 1 also has two fixing holes 4 located between the two nail holes 2, and a groove 3 is provided on the steel plate 1 on the same side as the position of the nail hole 2.

[0004] Due to the complex structure of the cervical pedicles, the axis is adjacent to blood vessels, nerves and spinal cord, and once the screw penetrates the pedicle, it may cause serious complications. In addition, there are few anatomical landmarks on the anterior surface of the cervical spine, and the distance between the cervical surface and the pedicles is far, making anterior cervical pedicle screw placement more difficult and risky.

[0005] Computer navigation technology has been widely used in spinal surgery, including cervical, thoracic and lumbar spine, and can provide accuracy and multi-angle real-time information that cannot be matched by previous clinical experience. However, the computer navigation technology currently used in clinical practice also has some disadvantages, such as insufficient accuracy, complex operation, expensive equipment, and long operation time. In addition, using the existing computer navigation system for pedicle positioning, patients must undergo surgery in hospitals with navigation equipment, which is currently difficult to promote widely. In hospitals without navigation equipment, repeated X-ray fluoroscopy is required to place screws, the operation time is long, the doctor and patient are exposed to a large amount of X-ray radiation, and it depends on the experience of the surgeon, with high technical requirements and high surgical risks. It has not yet been widely used in clinical practice.

[0006] In recent years, with the popularization of 3D printing technology, 3D printed guides have been tried for screw placement in orthopedic internal fixation surgery. Their safety and accuracy have been verified to a certain extent and have been initially applied in clinical practice.

[0007] However, the current screw placement guide devices have problems such as poor stability, and the puncture point and screw insertion direction are prone to deviation during pedicle screw placement. Summary of the invention

[0008] The first object of the present invention is to provide a guiding device for anterior cervical retrograde pedicle screw plate, which is used for guiding the placement of anterior cervical retrograde pedicle screw plate in the background technology.

[0009] The guide device includes a base plate and a nail channel. An embedding groove is provided on one side of the base plate, and the embedding groove is used to fit the steel plate in the background technology into the groove. A first through hole through which the Kirschner wire can pass is provided around the edge of the base plate. The nail channel is tubular and provided with two pairs. Both pairs of nail channels are fixed on the side of the base plate facing away from the embedding groove. The nail channels of the same pair are inclined in a V shape. Two pairs of second through holes coaxial with the nail channels are provided on the base plate, and the second through holes are provided at positions corresponding to the nail holes of the steel plate.

[0010] in:

[0011] Two forked legs are respectively provided on the edges of both sides of the surface where the embedding groove of the substrate is located. The legs include a positioning plate and a connecting rod connected between the positioning plate and the substrate. The legs are used to support the substrate at the connection between the desired fixed vertebra and the transverse processes on both sides, and the bottom surface of the positioning plate fits the support. The two positioning plates at the same end of the substrate have one end facing inward in a hook shape, which is used to hook and fit on both sides of the upper edge of the lower vertebra. The positioning plate has a fitting surface that is completely fitted with the anatomical structure in front of the desired fixed vertebra, and a fitting surface that is completely fitted with the anatomical structure of the front edge and part of the upper edge of the lower vertebra; the positioning plate is mainly provided to allow the fixing plate and the substrate to be more stably positioned on the desired fixed vertebra when the nails are placed.

[0012] Two first embedded blocks are provided in the embedding groove, and the two first embedded blocks can be respectively matched and embedded in the nail holes of the above-mentioned steel plate. Two second embedded blocks are provided in the embedding groove, and the two second embedded blocks can be respectively matched and embedded in the grooves of the above-mentioned steel plate; the second embedded blocks are provided with holes corresponding to the fixing holes, and the fixing screws are passed through the two holes to fasten the steel plate to the base plate. The first and second embedded blocks are mainly provided to allow the steel plate to be more fitly embedded in the embedding groove of the base plate.

[0013] The guide device is made of medical 3D printing material; the guide device is made by 3D printing, and its customization method is described below.

[0014] The guide device of the present invention has good stability during the retrograde placement of pedicle screw plates in the anterior cervical spine, can guide the insertion direction and depth of the pedicle screws during the operation, can avoid deviations in the puncture point and the insertion direction during the pedicle screw placement process, and complete the operation quickly and accurately.

[0015] The second object of the present invention is to provide a method for customizing the above-mentioned guide device.

[0016] The method for customizing the guide device comprises the following steps:

[0017] 1) According to the shape of the anterior cervical retrograde pedicle screw plate, a base plate that can match and cover the plate is constructed;

[0018] 2) Collect the original data of the cervical spine, build a three-dimensional vertebral model, select a suitable three-dimensional model of the steel plate, and virtually install the steel plate;

[0019] 3) Perform three-dimensional analysis of the pedicle screw channel of the fixation plate to ensure that the pedicle screw is located in the pedicle and passes through the screw hole of the plate;

[0020] 4) Extracting the partial contour of the connection between the required fixed vertebral body and the transverse processes on both sides, the extracted contour needs to avoid the fixed position of the steel plate, establishing a positioning plate whose bottom surface fits the extracted contour, and connecting a connecting rod between the positioning plate and the edge of the base plate, and then fitting the base plate connected with the positioning plate with the pedicle screw channel, establishing a screw channel coaxial with the channel on the base plate, and finally establishing a virtual guide device;

[0021] 5) 3D print the above-mentioned guide device.

[0022] In step 2):

[0023] The specific process of establishing a three-dimensional vertebral model is as follows: use CT or MRI to collect the original data of the cervical spine, import the continuous tomographic image data into the three-dimensional reconstruction software, first use grayscale segmentation to extract the vertebral boundary contour information area, and then use regional segmentation to extract the vertebral information area again. Generally, the software's default optimal reconstruction mode is used to establish a three-dimensional reconstructed vertebral model and export the model in STL format.

[0024] In step 4):

[0025] The intervertebral space that needs to be fused also needs to extract part of the outline of the upper edge of the vertebral body on both sides of the lower vertebra.

[0026] The customization method of the present invention uses 3D printing technology to produce a screw placement guide device based on a virtual model. The guide device can be customized according to the details of the cervical spine of different patients, and the insertion direction and depth of the pedicle screws can be guided during the operation. The plate fixation effect during the operation is good, and sufficient stability can be provided. No secondary surgical fixation is required, which reduces the patient's pain and medical expenses and accelerates recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention is a schematic diagram of the structure of anterior cervical retrograde pedicle screw plate in the prior art.

[0028] Figure 2 It is a schematic structural diagram of the guiding device of the present invention at a first viewing angle.

[0029] Figure 3 It is a schematic structural diagram of the guiding device of the present invention at a second viewing angle.

[0030] Figure 4 It is an assembly diagram of the guide device and the steel plate of the present invention.

[0031] Figure 5-Figure 8 Schematic diagram of each step of the customization method of the present invention.

[0032] Fig. 9 This is a diagram showing the effect of the present invention in practical application.

[0033] The numbers in the figure are: 1, steel plate; 2, nail hole; 3, groove; 4, fixing hole; 5, base plate; 6, embedding groove; 7, first through hole; 8, nail channel; 9, first embedded block; 10, second through hole; 11, second embedded block; 12, positioning plate; 13, connecting rod; 14, fixing screw; 15, nail placement direction. DETAILED DESCRIPTION

[0034] refer to Figure 2-Figure 4 The guiding device of this embodiment includes a base plate 5, a nail channel 8 and a support leg.

[0035] The base plate 5 is a rectangular plate with a certain thickness, and one side of the base plate 5 is provided with an embedding groove 6, which is used for the steel plate 1 to fit in the groove. The four corners of the edge of the base plate 5 are provided with first through holes 7 for passing the Kirschner wire. Two protruding first embedded blocks 9 and two second embedded blocks 11 are provided in the embedding groove 6. The two first embedded blocks 9 can be respectively matched and embedded in the nail holes 2 of the steel plate 1. The two second embedded blocks 11 can be respectively matched and embedded in the grooves 3 of the steel plate 1. The second embedded blocks 11 are provided with holes corresponding to the fixing holes 4, and fixing screws 14 are passed between the two holes to fasten the steel plate 1 to the base plate 5.

[0036] The nail channel 8 is tubular and is provided with two pairs. Both pairs of nail channels 8 are fixed on the side of the base plate 5 that is opposite to the embedding groove 6. The same pair of nail channels 8 are inclined in a V shape. The base plate 5 is provided with two pairs of second through holes 10 that are coaxial with the nail channels 8. The second through holes 10 are opened at positions corresponding to the nail holes 2 of the anterior cervical retrograde pedicle screw steel plate 1. When the screw is placed, the pedicle screw passes through the nail channel 8, the base plate 5 and the nail hole 2 in the direction of the screw placement 15 to fix the steel plate 1 on the cervical vertebral body.

[0037] There are four legs, and two of them are forked and arranged at the edges of both sides of the surface where the embedding groove 6 of the base plate 5 is located. The legs include a positioning plate 12 and a connecting rod 13 connected between the positioning plate 12 and the base plate 5. The legs are used to support the base plate 5 at the connection between the desired fixed vertebra and the transverse processes on both sides. The bottom surface of the positioning plate 12 is completely fitted at the support to have a fitting surface that is completely fitted with the anatomic structure of the front of the desired fixed vertebra. In addition, the inward ends of the two positioning plates 12 at the same end of the base plate 5 are hooked and used to hook and completely fit the upper edges of the lower vertebra to have a fitting surface that is completely fitted with the anatomic structure of the front edge and part of the upper edge of the lower vertebra.

[0038] refer to Figure 5-Figure 8 The steps of the customization method of the guide device of this embodiment are as follows:

[0039] 1) Based on the shape of the anterior cervical retrograde pedicle screw plate, a base plate that can fit the plate is constructed using computer 3D software; the shapes of the plate and base plate refer to Figure 1-Figure 4 ;

[0040] 2) Use CT or MRI to collect the original data of the cervical spine, import the continuous tomographic image data into the 3D reconstruction software, first use grayscale segmentation to extract the vertebral boundary contour information area, then use regional segmentation to extract the vertebral information area again, use the software default optimal reconstruction mode to establish a 3D reconstructed vertebral model, and export the model in STL format; according to the stage of cervical spine fixation, select the appropriate 3D steel plate model, import it into the 3D reconstruction software, virtually install the steel plate, and confirm that the steel plate specifications and position are appropriate; this step refers to Figure 5 , among which Figure 5 A and 5B are the main view and side view of the steel plate after virtual installation respectively;

[0041] 3) Perform three-dimensional analysis on the pedicle screw channel of the fixation plate to ensure that the pedicle screw is located in the pedicle and passes through the screw hole of the plate; this step refers to Figure 6 , among which Figure 6 A is a schematic diagram of the adaptation of the pedicle screw channel and the steel plate. Figure 6 B is a schematic diagram showing that the steel plate and the base plate are simultaneously adapted to the pedicle screw channel;

[0042] 4) Extract the partial contour of the connection between the vertebral body to be fixed and the transverse processes on both sides ( Figure 7 The C area and most of the D area in A), the intervertebral space to be fused also needs to extract the partial contours on both sides of the upper edge of the lower vertebral body ( Figure 7 The extracted contour needs to avoid the fixed position of the steel plate and avoid being too far outward to reduce the risk of accidentally injuring the vertebral arteries and nerve roots on both sides by stripping too much soft tissue during surgery; a positioning plate with a bottom surface that fits the extracted contour is established, and a connecting rod is connected between the positioning plate and the edge of the base plate, and then the base plate connected to the positioning plate is fitted with the pedicle screw channel, a screw channel coaxial with the channel is established on the base plate, and finally a virtual guide device is established; this step refers to Figure 7 and Figure 8 ,in Figure 7 A is a schematic diagram of contour extraction. Figure 7 B is a schematic diagram of the positioning plate and the contour adaptation. Figure 8 A and Figure 8 B are the front and side views of the substrate after the nail channel is constructed;

[0043] 5) 3D print the above-mentioned guide device.

[0044] The specific application method of this embodiment is:

[0045] 1) Fix the appropriate steel plate and the matching guide device selected by the computer before the operation with screws;

[0046] 2) Conventional anterior cervical surgical approach, exposing the cervical segment that needs to be fixed (including the position of the positioning plate), and temporarily fixing the plate and guide device with Kirschner wires at the position designed by the preoperative computer;

[0047] 3) Drill holes in the pedicles on both sides along the guide holes of the screw channel of the guide device;

[0048] 4) Remove the guide device and the steel plate, remove the fastening screws between the guide device and the steel plate, perform further surgery such as lesion resection, decompression or intervertebral bone fusion, place the steel plate according to the above-mentioned drilling opening position, and screw in the retrograde pedicle screws along the holes opened on both sides of the nail hole.

[0049] The advantages of this embodiment in practical application are: accurate, safe, low radiation, and solve the disadvantages of repeated fluoroscopy, puncture point and direction deviation during the anterior retrograde pedicle screw placement of the cervical spine, avoid blindness, reduce the exposure of medical staff and patients to radiation, improve the success rate of surgery, and shorten the operation time. Postoperative X-ray films of typical cases are as follows: Fig. 9 shown.

[0050] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A guide device for anterior retrograde cervical pedicle screw plate, characterized in that: It comprises a base plate and a nail channel; one side of the base plate is provided with an embedding groove, the embedding groove is used to match the steel plate in the groove, and the edge of the base plate is provided with a first through hole capable of passing the Kirschner wire; the nail channel is tubular and provided with two pairs, both pairs of nail channels are fixed on the side of the base plate facing away from the embedding groove, and the nail channels of the same pair are inclined in a V shape, and the base plate is provided with two pairs of second through holes coaxial with the nail channels, and the second through holes are provided at positions corresponding to the nail holes of the steel plate; Two forked legs are respectively provided on the two side edges of the surface where the embedding groove of the base plate is located, and the legs include a positioning plate and a connecting rod connected between the positioning plate and the base plate, and the legs are used to support the base plate at the connection between the required fixed vertebral body and the transverse processes on both sides, and the bottom surface of the positioning plate is attached to the support; The method for customizing the guide device comprises the following steps: 1) According to the shape of the steel plate, a base plate is constructed to match and cover the steel plate; 2) Collect the original data of the cervical spine, build a 3D vertebral model, select a suitable 3D steel plate model, and virtually install the steel plate; 3) Perform three-dimensional analysis of the pedicle screw channel of the fixation plate to ensure that the pedicle screw is located within the pedicle and passes through the screw hole of the plate; 4) Extract the partial contour of the connection between the vertebral body to be fixed and the transverse processes on both sides. The extracted contour needs to avoid the fixed position of the steel plate. Build a positioning plate with a bottom surface that fits the extracted contour, and connect the connecting rod between the positioning plate and the edge of the base plate. Then fit the base plate connected to the positioning plate with the pedicle screw channel, and build a screw channel coaxial with the channel on the base plate, and finally build a virtual guide device; 5) 3D print the guide device mentioned above.

2. The guide device according to claim 1, characterized in that: The two positioning plates at the same end of the base plate have one end facing inwards in a hook shape, and are used to hook and fit on both sides of the upper edge of the lower vertebral body.

3. The guide device according to claim 1, characterized in that: Two first embedding blocks are arranged in the embedding groove, and the two first embedding blocks can be matched and embedded in the nail holes of the steel plate respectively.

4. The guide device according to claim 1, characterized in that: Two second embedded blocks are arranged in the embedding groove, and the two second embedded blocks can be matched and embedded in the grooves of the steel plate respectively; holes corresponding to the fixing holes are arranged on the second embedded blocks, and fixing screws are passed through the two holes to fasten the steel plate to the base plate.

5. The guide device according to claim 1, characterized in that: The guide device is made of medical 3D printing material and is manufactured by 3D printing.

6. The guide device according to claim 1, characterized in that: The specific process of establishing a three-dimensional vertebral model is as follows: use CT or MRI to collect the original data of the cervical spine, import the continuous tomographic image data into the three-dimensional reconstruction software, first use grayscale segmentation to extract the vertebral boundary contour information area, then use regional segmentation to extract the vertebral information area again, and finally establish a three-dimensional reconstructed vertebral model and export the model in STL format.

7. The guide device according to claim 1, characterized in that: In step 4), the intervertebral space to be fused also needs to extract the partial contours on both sides of the upper edge of the lower vertebral body.

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