A lumbar interbody fusion cage, a preparation method of the cage and application thereof

Abstract

The application discloses a lumbar intervertebral fusion support, which is used for lumbar intervertebral bone grafting fusion and comprises a fusion support body and a pad with an anatomically fitted footprint surface; the fusion support body is X-shaped as a whole; the pad comprises an upper pad and a lower pad; the upper pad and the lower pad are detachably installed on the fusion support body; the fusion support body is made of a nickel-titanium alloy material; and the pad is made of PEEK. The application further discloses a preparation method of the lumbar intervertebral fusion support and a bone grafting fusion method using the lumbar intervertebral fusion support. The application further discloses application of the lumbar intervertebral fusion support in bone grafting fusion.

Description

Technical Field

[0001] This invention belongs to the field of medical devices and relates to a lumbar interbody fusion stent, a stent preparation method, and its application. Background Technology

[0002] Lumbar interbody fusion is the most important surgical procedure for reconstructing lumbar spine stability and alignment, and the number of surgeries performed has been increasing year by year in recent years. Regardless of the surgical approach—retroperitoneal or anterior peritoneal interbody fusion (ALIF), posterior interbody fusion (PLIF), transforaminal interbody fusion (TLIF), lateral interbody fusion via the psoas major muscle (XLIF / LLIF / DLIF), or lateral anterior oblique interbody fusion (OLIF)—the core technique involves implanting an interbody fusion cage and bone / bone replacement material into the prepared target intervertebral space. The fusion cage, through its structural and material design, plays a role in maintaining the height, lordosis, and immediate stability of the target intervertebral space to varying degrees. The bone / bone replacement material can induce bony fusion of the target intervertebral space, thereby achieving long-term stability.

[0003] The most commonly used lumbar interbody fusion cage in clinical practice both domestically and internationally is the box-shaped fusion cage. The basic procedure is as follows: during surgery, bone / bone replacement material is pre-filled into the bone graft groove of the fusion cage. The fusion cage is then installed onto the head end of the holder, and implanted into the target intervertebral space by striking the tail end of the holder. If necessary, a punch and hammer are used to adjust the direction and position of the fusion cage within the intervertebral space through striking. If the fusion cage height is greater than the target intervertebral space height, implantation may fail. Forced implantation by striking can cause damage to the vertebral endplate, the fusion cage becoming embedded in the vertebral body, or even fragmentation of the fusion cage. In some cases, excessive striking force can even cause the fusion cage / bone graft to be forced forward, breaking through the anterior annulus fibrosus and entering the retroperitoneum. If the fusion cage height is smaller than the target intervertebral space height, although the implantation process is easier, the footprint surface of the fusion cage cannot make close contact with the vertebral endplate, increasing the risk of the fusion cage regressing into the spinal canal or non-fusion of the target intervertebral space.

[0004] Some manufacturers and surgeons have designed, produced, and used a height-adjustable intervertebral fusion cage. This type of cage is characterized by its relatively small height before entering the intervertebral space, which is increased in height after entry via mechanical components (rotatable, advanceable struts). While this design achieves the goals of easy implantation and alignment with the intervertebral space height, it still has limitations. Firstly, because the height adjustment knob is located at the rear of the cage, it can only be placed longitudinally, which offers lower mechanical stability than oblique or transverse placement. Secondly, unlike hollow, box-shaped fusion cages (whose grafting slots can be filled with bone / bone replacement material), internal bone grafting in height-adjustable fusion cages is affected: if pre-grafting is performed externally, either the implanted bone / bone replacement material will affect the height adjustment of the fusion cage, or the pre-implanted bone / bone replacement material will not be able to make close contact with the vertebral endplate as the fusion height increases; even without pre-grafting and height adjustment after entry into the intervertebral space, the space-occupying effect of its mechanical components can restrict internal bone grafting. The aforementioned drawbacks of bone grafting will inevitably affect the amount of bone grafted to the target intervertebral space and the final fusion result.

[0005] Furthermore, due to individual differences in the anatomical morphology of the lumbar vertebral endplates, the aforementioned box-shaped fusion cages and height-adjustable intervertebral fusion cages cannot perfectly match the target intervertebral space in most patients. This results in a small contact area between the fusion cage footprint and the vertebral endplate (point contact rather than surface contact), leading to axial displacement, i.e., fusion cage subsidence (especially when the patient has osteoporosis), causing intervertebral nonfusion or recurrence of neurological symptoms. When the sagittal profile of the fusion cage does not match the lordosis of the target intervertebral space, it cannot effectively restore and maintain the lordosis of the target intervertebral space, which may cause compensatory malalignment of the adjacent intervertebral disc and accelerate its degeneration, inducing adjacent vertebral disease.

[0006] To better match the anatomical morphology of the intervertebral space with the fusion cage, researchers have used 3D printing technology to create personalized intervertebral fusion cages. Although 3D printing can effectively solve the problem of matching the shape of the fusion cage footprint surface with the vertebral endplate, the final opening height of the target intervertebral space during surgery cannot be predicted preoperatively. This can lead to discrepancies between the height of the 3D-printed fusion cage and the target intervertebral space, rendering the 3D-printed fusion cage unusable. Printing multiple fusion cages of different heights for a single target intervertebral space would obviously be wasteful. Summary of the Invention

[0007] In order to overcome the shortcomings of the existing technology, the purpose of this invention is to provide a lumbar interbody fusion stent and a stent preparation method.

[0008] This invention provides a lumbar interbody fusion stent, which includes a fusion stent body and a pad;

[0009] The main body of the fusion support is generally X-shaped;

[0010] The pad includes an upper pad and a lower pad; the upper pad and the lower pad are detachably mounted on the fusion scaffold body; in addition, other support structures such as support pads and support strips can be selected to replace the pad according to the actual situation and are detachably mounted on the fusion scaffold body; the pad includes an anatomical adapter part and a connecting part, the length a of the anatomical adapter part is 10-12mm, the width b is 6-10mm, and the minimum thickness is 2mm; the pad is obtained by personalized 3D printing and / or machining prefabrication, and the specific size is determined according to the actual measurement data of different people;

[0011] The upper pad is used to support the lower endplate of the upper vertebral body; the lower pad is used to support the upper endplate of the lower vertebral body.

[0012] The main body of the fusion support is an integrated structure, including two long plates with waist-shaped holes, namely the first long plate and the second long plate. The first long plate and the second long plate intersect in an X shape. In specific application scenarios, the lengths of the first long plate and the second long plate are generally equal.

[0013] The length l of the fusion stent body is 20-40mm, preferably 26-36mm. The width of the fusion stent body is basically the same as the length a of the pad, about 10-12mm. The height h of the fusion stent body is 6-14mm. The height of the lumbar intervertebral fusion stent includes the height of the fusion stent body and the thickness of the upper and lower pads, and is 10-18mm.

[0014] In one specific embodiment, the length l of the fusion support body is 26mm, the width of the fusion support body is 10mm, and the height h of the fusion support body can be selected from one or more of 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, etc.

[0015] Both ends of the first and second long plates are bent and extended, and are provided with horizontal support portions, namely an upper support portion and a lower support portion, respectively, located at the ends of the long plates. The thickness of the support portions is uniform, and the upper and lower support portions are parallel. The size of the support portions is basically matched with the size of the pad, that is, the length of the support portion is 10-12mm and the width is 6-10mm. The support portions can be integrally connected to both ends of the long plates. When the support portions are integrally connected to both ends of the long plates, additional connecting parts are eliminated, making the structure more stable and lighter overall.

[0016] The intersection of the two long plates is thicker, while the ends are thinner; the thickness of the support is uniform.

[0017] Furthermore, the upper pad is detachably mounted on the upper support portion, and the lower pad is detachably mounted on the lower support portion.

[0018] The aspect ratio of the first long plate and the second long plate is (3-10):1, preferably (5-8):1.

[0019] The upper support and the lower support are each provided with one or more slots, and the slots are also provided with slot threads. The shape of the slot can be circular or other shapes, such as regular hexagon, waist-shaped, etc. When the slot is waist-shaped, the engaging part can be an umbrella-shaped cap; when the slot is circular, the engaging part can be a semi-umbrella-shaped cap. Different engaging part shapes are used for different slot shapes to facilitate the installation of the pad.

[0020] The pad includes an anatomical adapter and a connecting part. In the pad, the shape, size, and number of the connecting part match the shape, size, and number of the slot. The pad is fixedly connected to the upper support or the lower support through the connecting part.

[0021] The thinnest part of the anatomical adapter is 2 mm, and the surface that contacts the vertebral endplate is called the footprint surface. The surface of the footprint surface is uniformly provided with anti-slip textures of thorn-like and / or striped structures. The depth c (distance from the highest point to the lowest point) of the thorn-like and / or striped structures on the anti-slip textures is 0.2-1 mm, and the distance d between two adjacent thorn-like and / or striped structures is 0.5-1.5 mm.

[0022] The connecting part is fixedly connected to the anatomical adapter part. The connecting part further includes a connecting body and a locking part. The anatomical adapter part, the connecting body, and the locking part are integrally formed and obtained by 3D printing and / or machining. A connecting thread is also provided between the connecting body and the locking part.

[0023] The number of connectors matches the number of slots, the size of the connectors matches the size of the slots, and the connecting threads match the slot threads.

[0024] The pad in this invention can be obtained by machining different commonly used models according to the anatomical morphology / subtype of the lumbar endplate of Chinese people, or it can be personalized and optimized based on the patient's medical imaging data (CT) and obtained by 3D printing.

[0025] When the fusion support body is in the martensitic phase in an ice-water environment (at a temperature of approximately 0°C), it can be deformed vertically by a special clamp / tool ​​to reduce its height, while there is no significant change in the left-right direction.

[0026] The fusion scaffold body is a shape memory type scaffold made of nickel-titanium alloy; the footprint surface is made of PEEK. In addition to the above materials, the fusion scaffold body can also be made of other shape memory-enabled, biocompatible materials, which can be selected according to actual needs.

[0027] The nickel-titanium alloy is a shape memory alloy. The degree of deformation of the fusion stent body is related to temperature. Specifically, when the temperature is low, the fusion stent body can be clamped by a clamp to reduce its height in the vertical direction, which is conducive to entering the intervertebral space. When it returns to normal temperature or body temperature, the fusion stent body can automatically return to its original shape and size.

[0028] In one optional embodiment, when the fusion stent body is placed in ice water and is in the Martensitic phase, it can be clamped by a clamp to reduce its height in the vertical direction. When it returns to normal temperature or body temperature, the fusion stent body can automatically return to its original shape and size.

[0029] The present invention also provides a method for preparing the above-mentioned lumbar interbody fusion stent, the method comprising the following steps:

[0030] S01. Standard components of X-shaped fusion stent bodies of different sizes that can be adapted to the intervertebral space are prepared using nickel-titanium shape memory alloy;

[0031] S02. Prefabricated pads that are adapted to different types / subtypes of lumbar endplates in Chinese people through machining, or pads that are adapted to the anatomical shape of lumbar endplates of a specific individual through 3D printing.

[0032] S03. Assemble the pad and the X-shaped fusion bracket body into a lumbar intervertebral fusion bracket.

[0033] In step S01, the preparation method of the standard part of the fusion bracket body is as follows: the plate material is prepared into a standard part by wire cutting, CNC milling, grinding, thermoforming, first heat treatment (350℃), first polishing (surface finish 3.2), second heat treatment, second polishing (surface finish 0.8), cleaning, inspection, laser marking, washing, drying (60℃), inspection, and packaging.

[0034] In step S02, the design and fabrication of a pad adapted to the anatomical shape of a specific individual's lumbar endplate through 3D printing includes the following steps:

[0035] Step S021: Obtain a three-dimensional vertebral body model by three-dimensional reconstruction of the patient's vertebral CT image data; wherein, the slice thickness during CT image scanning is ≤1mm;

[0036] Step S022: Import the model file of the prefabricated lumbar interbody fusion stent into the three-dimensional vertebral body model in step S021 and place it at the location where it will be implanted in the surgery.

[0037] Step S023: Extract the upper and lower vertebral body surfaces that are in direct contact with the pad of the lumbar intervertebral fusion stent, and regenerate the pad model file using the upper and lower vertebral body surfaces as the upper surface of the pad.

[0038] Step S024: Obtain the personalized design of the pad block by 3D printing based on the regenerated pad block model file.

[0039] In step S02, the process of prefabricating pads that are adapted to the different types / subtypes of lumbar endplates in Chinese people through machining is as follows:

[0040] The five-axis linkage milling and turning machine is used for high-precision cutting and manufacturing in all directions. Since the pad is clamped only once during the entire processing, the high-precision fit between the pad and the fusion bracket body is guaranteed. When the pad and the fusion bracket body are installed, they are completely matched and always remain in a pre-tight state after installation, thus ensuring that the pad does not loosen. The locking part on the pad uses a barbed anti-reverse function, and the sliding front design makes it easy for the pad to be installed into the slot of the fusion bracket body. The advantage of these two designs is that they ensure that there is no retraction after installation.

[0041] The present invention also provides a bone grafting fusion method using the above-mentioned lumbar interbody fusion stent, the method comprising:

[0042] S1. In an ice-water environment, when the main body of the lumbar intervertebral fusion frame is in the Maslow phase, the height can be reduced in the vertical direction by clamping it with a clamp. After installing four pads to complete the overall assembly, the target intervertebral space, which has been completely removed from the superior and inferior cartilaginous endplates, inner annulus fibrosus and nucleus pulposus tissue, is entered through an annulus fibrosus incision on the target intervertebral space.

[0043] S2. Under body temperature conditions, the main body of the lumbar intervertebral fusion stent automatically returns to its original size and shape, and the footprint surfaces of the upper pad and the lower pad form anatomically compatible contact with the lower endplate of the upper vertebral body and the upper endplate of the lower vertebral body of the target intervertebral space, respectively.

[0044] S3. The main bone grafting fusion method is to use autologous bone particles obtained from decompression for compression grafting within and around the lumbar intervertebral fusion stent. For the target intervertebral space of osteoporotic patients, an auxiliary bone grafting fusion method can be adopted, which involves casting a mixture of injectable calcium phosphate / calcium sulfate bone cement and autologous local decompression bone particles. This is to reduce the risk of stent subsidence by increasing the stress area of ​​the vertebral endplate.

[0045] In an optional embodiment, in step S1, a larger fusion stent may be placed obliquely or laterally within the target intervertebral space, or two smaller fusion stents may be placed parallel to each other in the anterior-posterior direction.

[0046] In one alternative embodiment, the composition ratio of injectable calcium phosphate / calcium sulfate bone cement and autologous local decompression bone particles is adjusted according to the patient's lumbar vertebral bone density to match the elastic modulus of the lumbar vertebrae.

[0047] In an optional embodiment, in step S3, a long-acting antibiotic may be added to the solid-liquid mixture of injectable calcium phosphate / calcium sulfate bone cement and autologous local decompression bone particles to prevent intervertebral disc infection that may occur after lumbar interbody fusion surgery.

[0048] The present invention also provides the application of the above-mentioned lumbar interbody fusion stent in bone grafting fusion.

[0049] The beneficial effects of this invention include:

[0050] 1) The modular design of the stent features detachable upper and lower pads on the upper and lower sides of the fusion stent body, respectively. The footprint surfaces of the pads contact the superior and inferior endplates of the vertebral body. The anatomical adaptation of the footprint surfaces can be achieved through pre-machining to match different types / subtypes of lumbar endplates in Chinese individuals, or through 3D printing to match the anatomical shape of a specific individual's lumbar endplate. This anatomical adaptation effectively reduces subsidence and displacement within the intervertebral space. Furthermore, the modular design of this stent can compensate for the surgeon's preoperative measurement error of the target intervertebral space height, avoiding the waste caused by printing multiple stents of different heights for a single intervertebral space.

[0051] Furthermore, the pad is made of PEEK (polyetheretherketone), which has good toughness and can avoid rigid connection with the upper and lower lumbar vertebrae, reducing the burden on the lumbar vertebrae. In addition, its elastic modulus is close to that of the vertebral body and it is compatible with the shape of the vertebral endplate, making it less prone to settling.

[0052] 2) The main body of the fusion stent adopts an X-shape. The X-shaped structural design has stronger deformation capacity and is more suitable for minimally invasive surgery. It is combined with a detachable pad to provide a sufficiently large area of ​​intervertebral support. The greater the intervertebral support provided, the greater the mechanical stability between the stent and the endplate, and the lower the risk of the fusion stent regressing into the spinal canal.

[0053] In addition, bone grafting can be performed within and around the ample frame contour of the X-shaped fusion scaffold body, which may reduce the incidence of nonfusion of the target intervertebral space.

[0054] 3) The main body of the fusion stent is made of shape memory material, preferably nickel-titanium shape memory alloy. When held in ice water by clamps, it will decrease in height to a certain extent. It can automatically restore its original shape at room temperature or body temperature. With the help of this deformability of the lumbar interbody stent, the main frame of the stent with the same height as the target intervertebral space can be reduced in height and width to a certain extent in the Martens phase. This makes it easier to pass through the narrow annulus fibrosus notch in the cross section and the relatively small intervertebral space edge in the head-to-tail direction of the human body. It avoids the need to enter the intervertebral space by impact as with conventional fusion devices, thereby reducing the risk of nerve, blood vessel and vertebral endplate damage. It can improve the convenience of implanting the prosthesis into the intervertebral space during lumbar interbody fusion surgery, and is especially suitable for minimally invasive lumbar interbody fusion under spinal endoscopy. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0056] Figure 1 This is a schematic diagram of the lumbar intervertebral fusion stent of the present invention.

[0057] Figure 2 This is a front view schematic diagram of the lumbar intervertebral fusion stent of the present invention.

[0058] Figure 3 This is a schematic diagram of the structure of the pad on the lumbar intervertebral fusion stent of the present invention.

[0059] Figure 4 This is a schematic diagram of the left side of the lumbar intervertebral fusion stent of the present invention.

[0060] Figure 5 This is a top view schematic diagram of the lumbar intervertebral fusion stent of the present invention.

[0061] Figure 6 This is a schematic diagram showing the dimensions of the lumbar intervertebral fusion stent of the present invention.

[0062] Figure 7 This is a schematic diagram showing the dimensions of the lumbar intervertebral fusion stent of the present invention.

[0063] Numbering in the diagram: 1-Fusion bracket body, 2-Padded block, 11-First long plate, 12-Second long plate, 13-Upper support, 14-Lower support, 15-Oval hole, 16-Slot, 21-Dissecting adapter, 211-Anti-slip texture, 22-Connecting part, 221-Connecting body, 222-Clamping part, 223-Connecting thread. Detailed Implementation

[0064] The invention will be further described in detail below with reference to the specific embodiments and accompanying drawings. Except for the contents specifically mentioned below, the processes, conditions, and experimental methods for implementing the invention are all common knowledge and general knowledge in the art, and the invention does not have any particular limitations.

[0065] This invention provides a lumbar interbody fusion stent, which is an assembled shape memory anatomically adaptable lumbar interbody fusion stent that can be used in lumbar interbody fusion surgery. The fusion stent includes a fusion stent body 1 and pads 2 (including an upper pad and a lower pad), and the upper pad and lower pad are detachably connected to the upper and lower sides of the fusion stent body 1, respectively. The fusion stent body 1 is made of nickel-titanium shape memory alloy, which can be clamped in ice water to a certain extent to reduce its height, and can automatically restore its original shape at room temperature or body temperature. With the help of this deformability, the convenience of implanting the prosthesis into the intervertebral space during lumbar interbody fusion surgery can be improved, especially for minimally invasive lumbar interbody fusion surgery under spinal endoscopy. Secondly, with the help of the anatomical adaptability of this stent, its settlement and displacement in the intervertebral space can be effectively reduced. In addition, the assembled design of this stent can compensate for the surgeon's preoperative measurement error of the target intervertebral space height, avoiding the waste caused by printing multiple prostheses of different heights for one intervertebral space.

[0066] Example 1

[0067] This embodiment provides a lumbar interbody fusion stent, which includes a fusion stent body 1 and a pad 2, as shown below. Figure 1 As shown;

[0068] The main body 1 of the fusion support is generally X-shaped;

[0069] The pad 2 includes an upper pad and a lower pad; the upper pad and the lower pad are detachably mounted on the fusion support body 1; as shown Figure 3 As shown, the pad 2 includes an anatomical fitting portion 21 and a connecting portion 22, as... Figure 6 , 7 As shown, the length a of the anatomical adapter 2 is 10 mm, the width b of the anatomical adapter 2 is 8 mm, and the minimum thickness of the anatomical adapter 2 is 2 mm.

[0070] The surface of the pad that contacts the vertebral endplate is the footprint surface;

[0071] The footprint surface of the upper pad is used to support the lower endplate of the upper vertebral body; the footprint surface of the lower pad is used to support the upper endplate of the lower vertebral body.

[0072] like Figure 2As shown, the fusion support body 1 is an integral structure, comprising two pieces each with a waist-shaped hole 15 (e.g., Figure 4 , 5 The long plates shown are the first long plate 11 and the second long plate 12, which are of the same length. The first long plate 11 and the second long plate 12 intersect in an X shape. The setting of the waist-shaped hole 15 enables the structure of the fusion support body 1 to have a certain elastic deformation capability.

[0073] Both ends of the first long plate 11 and the second long plate 12 are bent and extended, and are provided with horizontal support parts, namely an upper support part 13 and a lower support part 14, respectively, located at the ends of the long plates. The support parts are integrally connected to both ends of the long plates. When the support parts are integrally connected to both ends of the long plates, additional connecting parts are eliminated, making the structure more stable and lighter overall.

[0074] The intersection of the two long plates is thicker, while the ends are thinner; the thickness of the support is uniform.

[0075] The upper pad is detachably mounted on the upper support portion 13, and the lower pad is detachably mounted on the lower support portion 14.

[0076] The aspect ratio of the first long plate 11 and the second long plate 12 is 6:1.

[0077] The upper support portion 13 and the lower support portion 14 are each provided with one or more slots 16, and the slots 16 are also provided with slot threads.

[0078] In this embodiment, the slot 16 is waist-shaped and the locking part 222 is umbrella-shaped, which facilitates the installation of the pad 2 and also has a hook-type anti-retraction function. The sliding front design makes it easy for the pad to be installed into the slot of the fusion bracket body, ensuring that there is no retraction after installation.

[0079] like Figure 3 As shown, the pad 2 includes an anatomical fitting part 21 and a connecting part 22. The pad 2 is fixedly connected to the upper support part 13 or the lower support part 14 through the connecting part 22.

[0080] The anatomical adapter 21 has a uniform thickness, and its surface in contact with the vertebral endplate is a footprint surface. The footprint surface is uniformly provided with spiky anti-slip textures 211. The depth c (distance from the highest point to the lowest point) of the spiky structures on the anti-slip textures 211 is 0.4 mm, and the distance d between two adjacent spiky structures is 0.8 mm. Figure 6 As shown;

[0081] The connecting part 22 is fixedly connected to the anatomical adapter part 21, and includes a connecting body 221 and a locking part 222. The anatomical adapter part 21, the connecting body 221, and the locking part 222 are integrally formed and obtained by 3D printing and / or prefabrication by machining. A connecting thread 223 is also provided between the connecting body 221 and the locking part 222.

[0082] The number of connectors 221 matches the number of slots 16, and the size of connectors 221 matches the size of slots 16; the connecting thread 223 matches the thread of the slot.

[0083] When the fusion support body 1 is placed in ice water and is in the Martensitic phase, it can be clamped by a fixture to lower its height in the vertical direction.

[0084] The fusion scaffold body 1 is made of nickel-titanium alloy; the pad 2 is made of PEEK material; in addition to the above materials, the fusion scaffold body 1 can also be made of other materials with shape memory function and good biocompatibility, which can be selected according to actual needs.

[0085] The nickel-titanium alloy is a shape memory alloy with good biocompatibility. The deformation degree of the fusion scaffold body 1 is related to temperature. Specifically, when the temperature is low (in this embodiment, it is in an ice water environment), the fusion scaffold body 1 can be lowered by clamping with a clamp. When it returns to normal temperature or body temperature, the fusion scaffold body 1 with shape memory characteristics can automatically return to its original shape and size.

[0086] In an optional embodiment, when the fusion stent body 1 is placed in ice water in the Martensitic phase, it can be lowered in the vertical direction by clamping it with a clamp. When it returns to normal temperature or body temperature, the fusion stent body 1 can automatically return to its original shape and size.

[0087] In this invention, the dimensions of the lumbar interbody fusion support body 1 are as follows: length l is 36mm, width is 10mm, and height h is 14mm. Figure 6 As shown.

[0088] The present invention also provides a method for preparing the above-mentioned lumbar interbody fusion stent, the method comprising the following steps:

[0089] S01. Standard parts of X-shaped fusion stent bodies 1 of different sizes that can be adapted to the intervertebral space are prepared by using nickel-titanium shape memory alloy;

[0090] S02. A pad 2 that is prefabricated by machining to match the different types / subtypes of lumbar endplates of Chinese people, or a pad 2 that is 3D printed to match the anatomical shape of a specific individual's lumbar endplate.

[0091] S03. Assemble the pad 2 and the X-shaped fusion bracket body 1 to form a lumbar intervertebral fusion bracket.

[0092] In step S01, the preparation method of the standard part of the fusion bracket body 1 is as follows: the plate material is prepared into a standard part by wire cutting, CNC milling, grinding, thermoforming, first heat treatment (350℃), first polishing (surface finish 3.2), second heat treatment, second polishing (surface finish 0.8), cleaning, inspection, laser marking, washing, drying (60℃), inspection, and packaging.

[0093] The present invention also provides a bone grafting fusion method using the above-mentioned lumbar interbody fusion stent, the method comprising:

[0094] S1. In an ice-water environment, when the lumbar intervertebral fusion stent is in the Maslow phase, it is clamped by a clamp to slightly reduce its height in the vertical direction. After installing the pad and assembling the whole, it enters the target intervertebral space through a fibrous incision on the target intervertebral space, where the superior and inferior cartilaginous endplates, inner annulus fibrosus and nucleus pulposus tissue have been completely removed.

[0095] S2. Under body temperature conditions, the main body of the lumbar intervertebral fusion stent automatically returns to its original size and shape, and the footprint surfaces of the upper pad and the lower pad form anatomically compatible contact with the lower endplate of the upper vertebral body and the upper endplate of the lower vertebral body of the target intervertebral space, respectively.

[0096] S3. A bone grafting fusion method for lumbar interbody fusion, which mainly involves pressing and grafting autologous bone particles obtained from decompression within and around the lumbar interbody fusion framework, and / or supplementing with the casting of a mixture of injectable calcium phosphate / calcium sulfate bone cement and autologous local decompression bone particles to form a concrete casting lumbar interbody fusion procedure.

[0097] In an optional embodiment, in step S1, a larger fusion stent may be placed obliquely or laterally within the target intervertebral space, or two smaller fusion stents may be placed parallel to each other in the anterior-posterior direction.

[0098] In one alternative embodiment, the composition ratio of injectable calcium phosphate / calcium sulfate bone cement and autologous local decompression bone particles is adjusted according to the patient's lumbar vertebral bone density to match the elastic modulus of the lumbar vertebrae.

[0099] In an optional embodiment, in step S3, a long-acting antibiotic may be added to the solid-liquid mixture of injectable calcium phosphate / calcium sulfate bone cement and autologous local decompression bone particles to prevent intervertebral disc infection that may occur after lumbar interbody fusion surgery.

[0100] Example 2

[0101] This embodiment provides a lumbar interbody fusion stent, which includes a fusion stent body 1 and a pad 2;

[0102] The main body 1 of the fusion support is generally X-shaped;

[0103] The pad 2 includes an upper pad and a lower pad; the upper pad and the lower pad are detachably mounted on the fusion support body 1; the pad 2 includes an anatomical adapter 21 and a connecting part 22, the length a of the anatomical adapter 21 is 11mm, the width b of the anatomical adapter 21 is 7mm, and the minimum thickness of the anatomical adapter 21 is 2mm.

[0104] The surface of the pad that contacts the vertebral endplate is the footprint surface;

[0105] The footprint surface of the upper pad is used to abut against the lower endplate of the upper vertebral body; the footprint surface of the lower pad is used to abut against the upper endplate of the lower vertebral body.

[0106] The fusion support body 1 is an integral structure, including two long plates with waist-shaped holes 15, namely the first long plate 11 and the second long plate 12. The two long plates have the same length, and the first long plate 11 and the second long plate 12 intersect in an X shape. The waist-shaped holes 15 enable the fusion support structure to have a certain elastic deformation capability.

[0107] Both ends of the first long plate 11 and the second long plate 12 are bent and extended, and are provided with horizontal support parts, namely an upper support part 13 and a lower support part 14, which are provided at the ends of the long plates. The support parts are integrally fixedly installed on the long plates.

[0108] The intersection of the two long plates is thicker, while the ends are thinner; the thickness of the support is uniform.

[0109] The upper pad is detachably mounted on the upper support portion 13, and the lower pad is detachably mounted on the lower support portion 14.

[0110] The aspect ratio of the first long plate 11 and the second long plate 12 is 7:1.

[0111] The upper support portion 13 and the lower support portion 14 are each provided with one or more slots 16, and the slots 16 are also provided with slot threads.

[0112] In this embodiment, the slot 16 is circular, and the engaging part 222 is a semi-umbrella-shaped cap, which facilitates the installation of the pad 2.

[0113] The pad 2 includes an anatomical fitting part 21 and a connecting part 22. The pad 2 is fixedly connected to the upper support part 13 or the lower support part 14 through the connecting part 22.

[0114] The anatomical adapter 21 has a uniform thickness, and the surface of the footprint surface is uniformly provided with striped anti-slip textures 211; the depth of the striped structure on the anti-slip texture 211 (the distance from the highest point to the lowest point) is 0.5 mm, and the distance between two adjacent striped structures is 1 mm.

[0115] The connecting part 22 is fixedly connected to the anatomical adapter part 21, and includes a connecting body 221 and a locking part 222. The anatomical adapter part 21, the connecting body 221, and the locking part 222 are integrally formed and obtained by 3D printing and / or prefabrication by machining. A connecting thread 223 is also provided between the connecting body 221 and the locking part 222.

[0116] The number of connectors 221 matches the number of slots 16, and the size of connectors 221 matches the size of slots 16; the connecting thread 223 matches the thread of the slot.

[0117] The fusion support body 1 is in the Martens phase in an ice-water environment. It can be deformed in the vertical direction by being clamped by a special clamp, thus reducing its height.

[0118] The fusion support body 1 is made of nickel-titanium alloy; the pad 2 is made of PEEK material; in addition to the above materials, the fusion support body 1 can also be made of other materials with shape memory function, which can be selected according to actual needs.

[0119] The nickel-titanium alloy is a shape memory alloy with good biocompatibility. The deformation degree of the fusion stent body 1 is related to temperature. Specifically, when the temperature is low, the fusion stent body 1 can be lowered in the vertical direction by clamping it with a clamp; when the temperature returns to normal or body temperature, the fusion stent body 1 can automatically return to its original shape and size.

[0120] In an optional embodiment, the fusion stent body 1 is in the Martensitic phase in an ice-water environment. It can be lowered in the vertical direction by clamping with a clamp. When it returns to normal temperature or body temperature, the fusion stent body 1 with shape memory characteristics automatically returns to its original shape and size.

[0121] In this invention, the dimensions of the main body 1 of the lumbar intervertebral fusion stent are as follows: length l is 26mm, width is 10mm, and height h is 12mm.

[0122] Example 3

[0123] The lumbar interbody fusion stent of the present invention is prepared by means of the following steps:

[0124] S01. Standard parts of X-shaped fusion stent bodies 1 of different sizes that can be adapted to the intervertebral space are prepared by using nickel-titanium shape memory alloy;

[0125] S02, a pad 2 that is prefabricated by machining to adapt to the different types / subtypes of lumbar endplates of Chinese people, or a pad 2 that is 3D printed to adapt to the anatomical shape of a specific individual's lumbar endplate.

[0126] S03. Assemble the pad 2 and the X-shaped fusion bracket body 1 to form a lumbar intervertebral fusion bracket.

[0127] In step S01, the preparation method of the standard part of the fusion bracket body 1 is as follows: the plate material is prepared into a standard part by wire cutting, CNC milling, grinding, thermoforming, first heat treatment (350℃), first polishing (surface finish 3.2), second heat treatment, second polishing (surface finish 0.8), cleaning, inspection, laser marking, washing, drying (60℃), inspection, and packaging.

[0128] In step S02, the design and fabrication of a pad adapted to the anatomical shape of a specific individual's lumbar endplate through 3D printing includes the following steps:

[0129] Step S021: Obtain a three-dimensional vertebral body model by three-dimensional reconstruction of the patient's vertebral CT image data; the slice thickness during CT scanning is ≤1mm;

[0130] Step S022: Import the model file of the prefabricated lumbar interbody fusion stent into the three-dimensional vertebral body model in step S021 and place it at the location where it will be implanted in the surgery.

[0131] Step S023: Extract the upper and lower vertebral body surfaces that are in direct contact with the pad of the lumbar intervertebral fusion stent, and regenerate the pad model file using the upper and lower vertebral body surfaces as the upper surface of the pad.

[0132] Step S024: Obtain the personalized design of the pad block by 3D printing based on the regenerated pad block model file.

[0133] Example 4

[0134] When the lumbar interbody fusion stent of the present invention is used for bone grafting fusion, it includes the following steps:

[0135] S1. The main body of the lumbar intervertebral fusion stent to be implanted is placed in an ice water environment. The main body of the lumbar intervertebral fusion stent is in the Maslow phase in the ice water environment. Using a special clamping tool, the main body of the fusion stent is deformed in the vertical direction by clamping force to reduce its height. Then, four pads are installed. Then, through a fibrous annulus tear incision on the target intervertebral space, the lumbar intervertebral fusion stent is placed into the target intervertebral space where the superior and inferior cartilaginous endplates, inner annulus fibrosus and nucleus pulposus tissue have been completely removed. After the lumbar intervertebral fusion stent enters the target intervertebral space, before returning to its original size and shape, it can be moved within the target intervertebral space to a position that the surgeon deems appropriate. That is, it can be adjusted from the anterior-posterior direction when it enters to the oblique or transverse direction relative to the midsagittal plane of the human body, and can be placed in a more anterior position within the target intervertebral space.

[0136] S2. Under the influence of body temperature, the lumbar intervertebral fusion stent returns to its original size and shape. The footprint surfaces of the upper and lower pads contact the lower endplate of the upper vertebral body and the upper endplate of the lower vertebral body of the target intervertebral space, respectively, so that the lumbar intervertebral fusion stent is tightly supported by the target intervertebral space. The lumbar intervertebral fusion stent acts as the "steel skeleton" of the target intervertebral space.

[0137] S3. Next, autologous bone particles obtained from decompression are pressed and grafted within and around the lumbar interbody fusion framework. A mixture of injectable calcium phosphate / calcium sulfate bone cement and autologous local decompression bone particles is then poured in. The injectable calcium phosphate / calcium sulfate bone cement and autologous local decompression bone particles correspond one-to-one as "cement" and "pebbles", thus forming a concrete-cast lumbar interbody fusion method.

[0138] Using a shape-memory lumbar interbody fusion stent as the "steel skeleton" of the intervertebral space, and then casting a mixture of injectable calcium phosphate / calcium sulfate bone cement and autologous local decompression bone particles as "cement" and "pebbles", this forms a lumbar interbody fusion procedure that differs from the traditional "precast component pre-implanted bone impaction" method.

[0139] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0140] The terms "comprising," "including," "comprises," or "including" as used in embodiments of this invention indicate the presence of the stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof. This specification describes exemplary embodiments with reference to idealized exemplary cross-sectional views and / or plan views and / or perspective views. The term "and / or" includes any or all of the associated listed items. When an element is described as "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements present.

[0141] Similarly, when an element is described as being "on" another element, it can be directly on the other element or there can be intermediate elements. Conversely, the term "directly" indicates that there are no intermediate elements. Furthermore, while the terms first, second, third, etc., can be used to describe various elements, these elements should not be limited by these terms. These terms are merely used to distinguish one element from another. Therefore, without departing from the teachings of this application, an element referred to as a first element in some embodiments may be referred to as a second element in other embodiments. The same reference numerals or reference signs denote the same elements.

[0142] Due to factors such as manufacturing techniques and / or tolerances, the illustrated shapes may deviate from the intended form. Exemplary embodiments should not be construed as limited to the areas of the illustrated shapes, but should include shape deviations caused, for example, by manufacturing processes. The areas shown in the figures are substantially schematic, and the shapes are not intended to depict the actual shapes of the device areas, nor are they intended to limit the scope of the exemplary embodiments.

[0143] The scope of protection of this invention is not limited to the above embodiments. Any variations and advantages that can be conceived by those skilled in the art without departing from the spirit and scope of the inventive concept are included in this invention and are protected by the appended claims.

Claims

1. A lumbar interbody fusion stent, characterized in that, The fusion support includes a fusion support body (1) and a pad (2); The fusion support body (1) is generally X-shaped; the length of the fusion support body (1) is 20-40mm, the width of the fusion support body (1) is 10-12mm, and the height of the fusion support body (1) is 6-14mm. The main body (1) of the fusion support is an integral structure, including two long plates with waist-shaped holes (15) respectively, namely the first long plate (11) and the second long plate (12), and the first long plate (11) and the second long plate (12) intersect in an X shape; The first long plate (11) and the second long plate (12) are also bent and extended at both ends, and are provided with horizontal support parts, namely upper support part (13) and lower support part (14), which are provided at the ends of the long plates; the thickness of the support parts is uniform, and the upper support part (13) and the lower support part (14) are parallel. The aspect ratio of the first long plate (11) and the second long plate (12) is (3-10):1; The pad (2) includes an upper pad and a lower pad; the upper pad is detachably mounted on the upper support (13), and the lower pad is detachably mounted on the lower support (14); The upper support (13) and the lower support (14) are each provided with one or more slots (16), and the slots (16) are also provided with slot threads; The fusion support body (1) is in the martensitic phase in an ice water environment. It can be deformed in the vertical direction by clamping with tools, thereby reducing its height. The pad (2) includes an anatomical fitting part (21) and a connecting part (22), and the pad (2) is fixedly connected to the upper support part (13) or the lower support part (14) through the connecting part (22); The surface of the anatomical adapter (21) that contacts the vertebral endplate is a footprint surface, and the surface of the footprint surface is uniformly provided with anti-slip textures (211) with thorn-like and / or striped structures. The connecting part (22) is fixedly connected to the anatomical adapter part (21), including a connecting body (221) and a locking part (222). The anatomical adapter part (21), the connecting body (221), and the locking part (222) are integrally formed. A connecting thread (223) is also provided between the connecting body (221) and the locking part (222). The number of connectors (221) matches the number of slots (16), the size of connectors (221) matches the size of slots (16), and the connecting thread (223) matches the thread of slots; The pad (2) is obtained by personalized 3D printing, and the footprint surface on the pad (2) that contacts the vertebral endplate is adapted to the anatomical morphology of the vertebral endplate of the target intervertebral space of the specific patient.

2. The lumbar interbody fusion stent as described in claim 1, characterized in that, The main body (1) of the fusion support is made of nickel-titanium alloy; the pad (2) is made of PEEK.

3. The lumbar interbody fusion stent as described in claim 1, characterized in that, The length of the anatomical adapter (21) is 10-12 mm, the width is 6-10 mm, and the minimum thickness is 2 mm.

4. The lumbar interbody fusion stent as described in claim 1, characterized in that, The depth of the spikes and / or stripes on the anti-slip texture (211) is 0.2-1 mm, and the distance between two adjacent spikes and / or stripes is 0.5-1.5 mm.

5. A method for preparing a lumbar interbody fusion stent as described in any one of claims 1-4, characterized in that, Includes the following steps: S01. Standard parts of X-shaped fusion scaffold bodies (1) of different sizes are prepared using nickel-titanium shape memory alloy; S02, 3D printing to create a pad that matches the anatomical shape of the lumbar endplate of a specific individual (2). S03. Assemble the pad (2) and the X-shaped fusion support body (1) into a lumbar intervertebral fusion support.

6. The preparation method according to claim 5, characterized in that, In step S02, the design and fabrication of a pad adapted to the anatomical shape of a specific individual's lumbar endplate through 3D printing includes the following steps: Step S021: Obtain a three-dimensional vertebral body model by three-dimensional reconstruction of the patient's vertebral CT image data; Step S022: Import the model file of the prefabricated lumbar interbody fusion stent into the three-dimensional vertebral body model in step S021 and place it at the location where it will be implanted in the surgery. Step S023: Extract the upper and lower vertebral body surfaces that are in direct contact with the pad of the lumbar intervertebral fusion stent, and regenerate the pad model file using the upper and lower vertebral body surfaces as the upper surface of the pad. Step S024: Obtain the personalized design of the pad block by 3D printing based on the regenerated pad block model file.

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