An enhanced pointed bone tunnel braided cage device, method of manufacture, and bone tunnel enhancement system

Abstract

The application discloses an enhanced pointed bone tunnel braided cage device, a manufacturing method and a bone tunnel reinforcing system. The device comprises a long tubular sleeve body with a cavity, which is formed by the cross-braiding of at least two groups of single filaments with different rigidities. The sleeve body is elastically stretchable in the axial and radial directions. In use, the device is pre-inserted into a bone tunnel, and then a bone screw is screwed, thereby forming mechanical interlocking between the bone interface and the bone screw. The thick and thin single filaments are interwoven to form the inner and outer surface protrusions, thereby constituting a double-interface resistance-increasing structure. The sleeve body is provided with different braiding density partitions in the axial direction, which are suitable for the differences in the mechanical properties of cortical bone and cancellous bone. In combination with the reinforcing ribs and the directional resistance-increasing structure on the surface of the single filaments, the effect of easy implantation in the forward direction and difficult extraction in the reverse direction is achieved. The application effectively solves the problems of complicated operation, secondary damage to bone, poor long-term stability and the like existing in the existing bone screw reinforcing mode, has a wide size adaptation range, has strong gripping force, and is especially suitable for clinical scenes with poor bone conditions or scenes requiring revision and reinforcement.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to an enhanced pointed bone tunnel braided cage device, its manufacturing method, and a bone tunnel reinforcement system. Background Technology

[0002] Fracture is an acute, mechanically destructive process, and fracture repair usually requires the use of internal or external fixators to reduce the fracture. Clinically, internal fixation is a common method for fracture treatment. For example, the plate fixation system used for limb fractures often uses an "eccentric drilling" technique to tighten the screws with the cortical bone, forming a stable support structure through the rigid connection of the "screw-plate". Another example is the pedicle screw system commonly used for spinal fractures, where the screws obtain holding force by engaging with the cortical or cancellous bone through threads, and the connecting rods rigidly connect the screws of adjacent vertebrae to restore vertebral height and spinal alignment.

[0003] Bone screws, as one of the most basic internal fixation devices, generate holding force through their threaded design and engagement with the bone, serving as the most critical anchor point in the entire fixation system. However, in clinical fracture fixation surgery, fixation system failure due to screw loosening and dislodgement is a common complication: screw loosening and dislodgement account for 20%-30% of spinal internal fixation failures, second only to osteonecrosis and collapse; in limb fracture fixation failures, screw stripping or loosening accounts for 43%, far exceeding screw breakage; decreased bone density increases the risk of loosening by more than three times. The causes of fixation failure can be divided into internal and external factors: internal factors mainly include poor bone quality in patients, osteoporosis, or bone destruction caused by tumors leading to decreased bone density, resulting in weak screw holding force and a tendency for "cutting" loosening; external factors include poor screw placement, incorrect orientation, excessive tapping, and incorrect selection of internal fixation. Failure is often the result of the combined effect of internal and external factors, with the core contradiction being insufficient holding force at the bone-screw interface and excessive mechanical load on the internal fixation.

[0004] To address the aforementioned issues, common reinforcement methods in existing technologies include: First, bone cement reinforcement, a classic method for treating osteoporosis, but it carries risks such as bone defects and leakage compressing nerves during screw removal. Furthermore, bone cement, as a permanent foreign body, may form a fibrous membrane at the screw-bone interface, affecting long-term stability. Second, using absorbable screws for local fixation of the screw track, but their strength is generally lower than that of metal screws, posing risks of material-related reactions such as delayed aseptic inflammation. Third, extending the fixation segment, but this sacrifices more spinal mobility. If fixation has failed, thicker and longer screws are usually required to enhance holding power. However, due to anatomical limitations, blindly increasing screw size increases the risk of pedicle fractures, vascular and nerve damage, and further damages residual bone. This procedure is difficult and requires highly skilled surgeons, and such patients are often in poorer physical condition and may have weaker healing abilities.

[0005] Furthermore, existing novel auxiliary fixation methods also have many shortcomings. For example, while connecting pedicle screws with auxiliary fixation pads and adding sacral wing screws to form an integrated structure can enhance cortical bone retention in specific areas, the small size of the added screws and the complex system structure significantly increase the difficulty of surgical operation and are highly dependent on the patient's specific bone anatomical conditions. Another example is the use of 3D-printed bio-woven sleeves with regular holes, which increase contact area and promote bone ingrowth by pre-inserting pilot holes before screwing in screws. However, the inner diameter and hole size of such sleeves are fixed, limiting the size of compatible screws. More importantly, when the threads attach to the inner wall of the sleeve, its outer wall remains relatively smooth, resulting in poor long-term locking and stability of the implanted screws inside the screw holes.

[0006] In summary, current clinical methods for reinforcing or re-fixing bone screws generally suffer from problems such as cumbersome procedures, secondary damage to fractures, and poor long-term stability. Furthermore, a comprehensive solution is lacking that can simultaneously address both insufficient holding force at the bone-screw interface and excessive mechanical load on internal fixation. Therefore, it is necessary to provide a new bone tunnel reinforcement device to overcome the shortcomings of existing technologies. Summary of the Invention

[0007] To address the challenges of cumbersome procedures, secondary damage to fractures, poor long-term stability, and susceptibility to complications associated with existing bone screw reinforcement or revision methods, and the inability to simultaneously resolve insufficient holding force at the bone-screw interface and excessive mechanical load on internal fixation, this invention provides an enhanced pointed bone tunnel braided cage device, its manufacturing method, and a bone tunnel reinforcement system. The braided cage device of this invention, positioned between the bone block and the screw, can adaptively deform and redistribute stress, significantly improving initial and long-term fixation stability.

[0008] This invention is implemented using the following scheme: This invention proposes an enhanced pointed bone canal braided cage device, comprising a long, tubular sleeve body with a cavity; the sleeve body is elastically expandable and contractable along the axial and radial directions, and is made of at least two sets of monofilaments with different rigidities woven together to outline a mesh structure; the sleeve body includes a first end and a second end in opposite directions, the first end being a closed end for receiving the end of a bone screw; the second end being an open end serving as the insertion port for the bone screw; the device is used for pre-insertion into the bone canal, and after the bone screw is screwed in, it is positioned between the bone screw and the bone canal wall to form a mechanical interlocking structure that provides interfacial resistance; the sleeve body is provided with braiding density zones of different densities along the axial direction to adapt to bone tissue with uneven density along the vertical direction of the bone structure.

[0009] In one embodiment, the at least two sets of monofilaments with different rigidities include at least two sets of monofilaments with different sizes, and the at least two sets of monofilaments with different rigidities are arranged alternately and woven in a cross-helical pattern.

[0010] In one embodiment, the at least two sets of monofilaments of different sizes include a coarse monofilament set and a fine monofilament set. The coarse monofilament set includes multiple coarse monofilaments that are spirally interwoven in both directions along the axis of the sleeve body. The fine monofilament set includes multiple fine monofilaments that are spirally interwoven in both directions along the axis of the sleeve body. The coarse monofilaments and the fine monofilaments are arranged alternately.

[0011] In one embodiment, multiple protrusions are formed at the intersection of the monofilaments, and the protrusions are distributed on the inner and outer surfaces of the sleeve body.

[0012] In one embodiment, the diameter of the coarse monofilament is in the range of 0.25-0.40 mm, the diameter of the fine monofilament is in the range of 0.10-0.25 mm, and the thickness of the protrusion is 0.20-0.80 mm.

[0013] In one embodiment, the cross-section of the closed end is circular, and the closing method is one of hot melting, adhesive bonding, ultrasonic welding or sleeve binding, with a closing length of 3-10mm.

[0014] In one embodiment, at least one reinforcing rib is also provided inside the sleeve body. The reinforcing rib is distributed along the axial direction of the sleeve body to withstand bone screw cutting and maintain the structural integrity of the sleeve body.

[0015] In one embodiment, the number of reinforcing ribs is 2-6, which are sandwiched in the middle of the double-layer braided structure, or merged into the single-layer braided structure as the weaving process progresses.

[0016] In one embodiment, the surface of the monofilament is provided with a directional resistance-enhancing structure, which includes at least one of barbs, herringbone patterns, or directional rough textures.

[0017] In one embodiment, the barb structure is arranged in a spiral, a ring, or a unidirectional oblique tooth arrangement.

[0018] The present invention also proposes a bone canal reinforcement system, comprising an enhanced pointed bone canal braided cage device and a bone screw as described above, wherein the device is used for pre-insertion into the bone canal, and the bone screw is used for screwing into the cavity of the device, such that the device is positioned between the bone screw and the bone canal wall to form a mechanical interlocking structure that can provide interfacial resistance.

[0019] The present invention also proposes a method for manufacturing an enhanced pointed bone channel woven cage device, comprising the following steps: S1: Provide at least two sets of monofilaments with different stiffness; S2: Arrange the at least two sets of monofilaments at intervals and weave them in a spiral cross-braid along the forward and reverse directions of the axial direction to form a long tubular braided structure with a mesh structure; S3: Cut the woven structure and form a gathered and closed end at one end; S4: Heat-set the woven structure after cutting and closing to obtain the enhanced pointed bone channel woven cage device.

[0020] In one embodiment, reinforcing ribs are placed at the pre-reserved holes in the braiding disc during the weaving process, so that the reinforcing ribs are incorporated into the monofilament cross structure as the weaving process progresses.

[0021] In one embodiment, different weaving counts are set in segments to form weaving density zones with varying density along the axial direction.

[0022] In one embodiment, step S4 involves heat-setting the cut and closed woven structure, which includes: fitting the cut and closed woven structure into a heat-setting fixture and holding it at a temperature close to the heat distortion temperature of the monofilament material for 15-30 minutes.

[0023] The technical solution provided by this invention has the following technical effects: 1. This invention provides an enhanced pointed bone channel braided cage device, manufacturing method, and bone channel reinforcement system, comprising a long tubular sleeve body with a cavity, the sleeve body being cross-woven from at least two sets of monofilaments with different rigidities, the sleeve body being capable of elastic expansion and contraction along the axial and radial directions; the device is used to form a mechanical interlock between the bone interface and the bone screw after pre-insertion of the bone channel; through the elastic adaptive structure, a wide range of size adaptations and optimized stress distribution are achieved.

[0024] 2. In some embodiments, the device uses coarse and fine monofilaments arranged in a cross-weaving pattern to form a hollow long tubular sleeve body, and reinforcing ribs are embedded in the axial direction. The device has excellent elasticity and extensibility in the radial direction, and can adapt to screws and holes of different diameters, thus overcoming the inherent defects of traditional solid reinforcement materials that have strict requirements for size matching and cause severe bone wear.

[0025] 3. Through a dual-interface resistance-increasing and dispersion mechanism, the overall gripping force at the screw-bone interface is significantly improved, making it particularly suitable for complex bone conditions. The device acts as a "shield" between the screw and bone, establishing two high-friction interfaces: "screw-device" and "device-bone." The protrusions on the inner surface of the device engage with the screw threads, generating significant frictional resistance. This resistance is effectively transmitted to the contact interface between the outer surface of the device and the bone canal through the integrity of the woven structure. Attempting to pull out the screw requires overcoming the combined forces of these two interfaces simultaneously. The shaped roughness or barbed structure of the monofilament surface achieves easy insertion in the antegrade direction and difficult extraction in the reverse direction. The device's sparse-dense partitioning, matching the vertical bone structure, also significantly improves axial pull-out force. For cases with poor bone quality, requiring bone canal enlargement for revision surgery, or needing to replace large screws without further hole enlargement, this device provides a reliable solution for achieving immediate high gripping force without excessive damage to healthy bone tissue.

[0026] 4. The pointed tip design optimizes implantation operability, improving surgical efficiency and safety. This tip allows for smooth insertion into the bone tunnel, avoiding cumbersome alignment operations in a narrow surgical field, saving surgical time, and reducing intraoperative risks caused by difficulties in implant alignment.

[0027] 5. Materials and manufacturing processes endow the device with long-term stability, economy, and biointegration potential. Utilizing bio-inert thermoplastic polymers and combining customizable weaving and heat-setting processes, the device is precisely and stably manufactured to target diameters and lengths by high-temperature heat-setting onto a fixture of a specific diameter. This perfectly adapts to variations in bone hole diameter and depth at different anatomical sites. The continuous, open, porous network formed by the woven structure provides potential physical space and channels for the ingrowth of bone cells and blood vessels, increasing the device's stability over time and providing long-term fixation stability for patients. Attached Figure Description

[0028] Figure 1 This is a front view of the enhanced pointed bone channel woven cage device according to an embodiment of the present invention; Figure 2 This is a partial enlarged view of the enhanced pointed bone channel woven cage device according to an embodiment of the present invention; Figure 3 This is a front view of the bone tunnel enhancement system according to an embodiment of the present invention; Figure 4 This is a partially enlarged view of the reinforcing ribs in the enhanced pointed bone channel braided cage device according to an embodiment of the present invention; Figure 5 This is a partially enlarged view of the enhanced pointed bone channel braided cage device according to an embodiment of the present invention, showing the double-layer braided structure and reinforcing ribs; Figure 6This is a front view of the enhanced pointed bone channel braided cage device of the present invention, in which the closing end of the braided structure is bound by a sleeve during manufacturing. Figure 7 This is a front view of the enhanced pointed bone channel braided cage device of the present invention during the manufacturing process, showing the braided structure being shaped. Figure 8 This is a schematic diagram of the reinforced pointed bone channel woven cage device of the present invention, showing 20 coarse monofilaments and 20 fine monofilaments arranged at intervals during manufacturing. Figure 9 This is a schematic diagram of the spindle movement trajectory during the manufacturing of the enhanced pointed bone channel braided cage device according to an embodiment of the present invention; Figure 10 This is a perspective view of the impeller with pre-drilled holes for reinforcing ribs used in the manufacturing of the enhanced pointed bone channel woven cage device according to an embodiment of the present invention. Figure 11 This is a flowchart illustrating the manufacturing method of the enhanced pointed bone channel woven cage device according to an embodiment of the present invention; Figure 12 It is a bar chart comparing the mechanical increase before and after using the device of the present invention under simulated osteoporosis conditions; Figure 13 It is a bar chart that compares the screw pullout resistance of different structural devices under the same conditions of bone density, bone screws, and pre-drilling. Figure 14 It is a bar chart comparing the pull-out force of devices constructed from shaped and circular cross-section monofilaments under different bone densities and the same experimental conditions. Figure 15 This is a bar chart comparing the mechanical properties of using original-size bone screws for reinforcement and using original-size bone screws in conjunction with the device of this invention, simulating normal drilling and screw reinforcement scenarios and overhauling and enlarging scenarios. Detailed Implementation

[0029] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention, primarily used to illustrate the embodiments and to explain the operating principles of the embodiments in conjunction with the relevant descriptions in the specification. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of the present invention. Components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0030] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0031] Example 1 Reference Figures 1-15This embodiment provides an enhanced pointed bone tunnel braided cage device 1, which is suitable for pre-inserting bone tunnels and then screwing in implants such as bone screws. The device forms an interface resistance between the bone tunnel wall and the bone screw, thereby forming a high-friction, mechanically interlocking enhanced structure between the implant and the bone tunnel to enhance the fixation effect of implants such as bone screws.

[0032] Reference Figures 1-2 The woven cage device 1 includes a long tubular sleeve body 10 with a cavity. The sleeve body 10 includes a first end 11 and a second end 12 that are opposite in direction. The first end 11 is a closed end that is used to receive the tip or end of the bone screw (i.e., the end opposite in direction to the head with a larger diameter of the bone screw). The second end 12 is an open end that serves as the insertion port for the bone screw.

[0033] The sleeve body 10 is woven from multiple monofilaments 13 to outline the mesh structure 14. The shape of the mesh 14 can be a parallelogram, or further, a rectangle, a square, etc. In some other embodiments, the shape of the mesh 14 can also be other polygons. In this embodiment, the mesh 14 of the sleeve body 10 is a parallelogram with an area of ​​approximately 0.5-6.0 square millimeters. When the sleeve body 10 is subjected to axial force, the mesh 14 can elastically expand and contract according to the direction of the force, so that the sleeve body 10 as a whole presents different diameters, thereby adapting to screws and bone tunnels of different diameters, and elastically changing with the shape of the screw or bone tunnel interface. The maximum deformation of the sleeve body 10 can reach 1.5-2.5 times its natural diameter. This design allows a single woven cage to adaptively match various bone screws of different diameters and enlarged revision bone tunnels, greatly improving the flexibility of clinical use.

[0034] The sleeve body 10 is woven from at least two sets of monofilaments 13 with different rigidities. These two sets of monofilaments with different rigidities can be two sets of monofilaments of different sizes, resulting in different rigidities (e.g., ...). Figure 2 The diagram shows coarse monofilament 21 and fine monofilament 31, or two sets of monofilaments of different materials, resulting in different rigidities. When at least two sets of monofilaments with different rigidities are arranged alternately and woven in a spiral pattern, asymmetrical deformation occurs at the interlacing point due to their different rigidities: when the more rigid monofilament presses on the less rigid monofilament, the less rigid monofilament (such as a thinner or softer one) is passively bent inward or outward, thus forming multiple protrusions on both the inner and outer surfaces of the sleeve body 10. The protrusion height presented by the interlacing of monofilaments with the same rigidity is between the two cases mentioned above. Therefore, different monofilament interlacing situations or different layers of weaving structures will form a variety of protrusion height combinations.

[0035] When the bone screw is screwed in, the protrusions on the inner surface of the sleeve body 10 bear the compressive force of the screw threads and transmit the pressure through the monofilament to multiple protrusions on the outer surface of the sleeve body 10. The pressure is then dispersed and transmitted to the bone wall, forming a double-interface resistance-increasing structure on both the inner and outer surfaces. During the screwing process, the cutting force of the screw threads acts on the inner surface and is transmitted along the monofilament to the outer surface. The height and curvature of the multiple protrusions on the outer surface change accordingly, bearing and dispersing the compressive force of the screw threads, and then evenly transmitting the pressure to the bone tunnel interface. This characteristic allows the sleeve body 10 to act as an interface for redistributing stress between the bone tunnel and the screw, i.e., absorbing the gripping force of the screw threads on the bone tunnel, and then transmitting the pressure through the inner and outer protrusions to form multiple contact points with the bone wall, increasing the contact area and reducing local pressure. For patients with poor bone conditions, the screw's gripping points on the bone tunnel are reduced, and its stability is greatly reduced. The protrusions on the sleeve body 10 can cooperate with the screw to form more anchoring points that engage with the bone wall, thereby increasing the resistance to the screw being pulled out.

[0036] Specifically, in this embodiment, at least two sets of monofilaments with different rigidities include at least two sets of monofilaments with different sizes, including a coarse monofilament group 2 and a fine monofilament group 3. The coarse monofilament group 2 includes multiple coarse monofilaments 21 that are spirally woven in both directions along the axis of the sleeve body 10. The fine monofilament group 3 includes multiple fine monofilaments 31 that are spirally woven in both directions along the axis of the sleeve body 10. The coarse monofilaments 21 and fine monofilaments 31 are arranged alternately to achieve the double-interface resistance-increasing structure on the inner and outer surfaces as described above. The weaving direction of the monofilaments can adopt a 2-over-2 method, that is, floating above two monofilaments in opposite directions and then sinking below two monofilaments; the weaving method can also be plain weave or twill weave. In addition, the monofilaments 13 constituting the sleeve body 10 are not limited to at least two sets of monofilaments with different sizes, but can also be a combination of monofilaments of two or more different materials or colors.

[0037] The difference in diameter between the coarse monofilament 21 and the fine monofilament 31 directly determines the difference in protrusion height. The larger the difference, the more pronounced the internal and external concavities and convexities, and the rougher the surface, theoretically resulting in stronger gripping force; the smaller the difference, the smoother the surface. By adjusting the diameter combination of the coarse monofilament 21 and the fine monofilament 31, the surface roughness / friction characteristics of the sleeve body 10 can be flexibly controlled within the same weaving process framework, thereby adapting to the needs of different bone densities and different clinical scenarios. Specifically, in this embodiment, the diameter range of the coarse monofilament 21 is 0.25-0.40 mm, the diameter range of the fine monofilament 31 is 0.10-0.25 mm, and the protrusion thickness is 0.20-0.80 mm, thereby enabling flexible control of the surface roughness / friction characteristics of the device to adapt to the needs of different bone densities and different clinical scenarios.

[0038] Furthermore, protrusions can also be formed at the intersections of coarse monofilaments 21 and fine monofilaments 31, meaning that protrusions can be formed from the intersections of any monofilament 13. However, the height difference of the protrusions formed at the intersections of coarse monofilaments 21 and fine monofilaments 31 is greater, which plays a better role in enhancing resistance.

[0039] Furthermore, the more rigid monofilaments (e.g., thick monofilament 21) can provide axial support, maintaining the straightness of the sleeve body 10 in the axial direction and preventing the entire device from collapsing, excessively twisting, or breaking under the high torque of the screw. The less rigid monofilaments (e.g., thin monofilament 31) have better flexibility. When the screw is screwed in or the bone tunnel is irregular, it can undergo elastic deformation, closely conforming to the irregular bone tunnel wall and the screw thread shape, improving the overall adaptability and radial elastic expansion and contraction capacity; thus, it can balance the mechanical strength and flexibility required by the woven cage device 1 during implantation surgery.

[0040] The sleeve body 10 has weave density zones of varying spacing along the axial direction to accommodate bone tissue with uneven density along the vertical direction of the bone structure. Specifically, refer to... Figure 1 , Figure 3 The sleeve body 10 includes a loosely woven section 101 and a densely woven section 102. The densely woven section 102 corresponds to the cortical bone region, and the loosely woven section 101 corresponds to the cancellous bone region. Because the vertical density of bone structure is not uniform, the thread design of the bone screw 200 is derived from the differences in microstructure between cortical and cancellous bone: cortical bone is dense and hard, providing the main support and strength, and the screw pitch corresponding to the segment is usually denser (e.g., ...). Figure 3 In the middle segment (202), to allow more threads to contact the cortical bone and generate higher local compressive stress to obtain greater holding force; the cancellous bone is composed of trabeculae and is porous and spongy, so the screw pitch of the corresponding segment is large and the tooth crest is wide and flat (e.g. Figure 3 The middle segment 201 is used to distribute pressure over a larger area of ​​the trabecular bone network. Based on this, the sleeve body 10 increases the braiding density (i.e., increases the braiding angle between the monofilament and the axis) in the cortical bone region to form a dense section 102, which reduces the spacing between monofilaments and increases the number of inner and outer protrusions. When the threads in the cortical bone region compress the sleeve body 10, the smaller thread spacing causes it to sink shallower into the thread valley, resulting in multiple protrusions interacting with the bone surface and increasing the local compressive stress on the bone wall. In the cancellous bone region, the braiding density is reduced to form a sparse section 101, which increases the spacing between monofilaments and reduces the number of protrusions. When the wide threads compress the sleeve body 10 and act on the trabecular bone, it causes it to sink deeper into the thread valley but not completely fit the thread valley, thereby supporting more volume of trabecular bone, increasing the contact area, dispersing the screw interface pressure, and enhancing the stability of the cancellous bone region.

[0041] Reference Figure 3At least one reinforcing rib 4 is also interspersed within the sleeve body 10. The reinforcing rib 4 is distributed along the axial direction of the sleeve body 10 to withstand bone screw cutting and maintain the structural integrity of the sleeve body 10. The number of reinforcing ribs 4 is 2-6, and they can be distributed within the double-layered braided structure, such as... Figure 4 The double-layer braided sleeve body 10a shown in the figure can also be incorporated into a single-layer braided structure during the braiding process, such as... Figure 3 The single-layer braided sleeve body 10 is shown in the figure. The reinforcing ribs 4 are composed of shape-memory-free braided yarns, flat yarns, multifilaments, monofilaments, or shaped yarns with a diameter of 0.2-0.6mm or 200-500D, interlaced between the monofilaments and fixedly connected to both ends of the sleeve body 10. When the thread rotates and cuts on the reinforcing ribs, the reinforcing ribs 4 can prevent the monofilaments from excessively indenting into the thread valleys, allowing more convexity to act on the bone wall; even if some monofilaments 13 are cut and broken, the reinforcing ribs 4 can still maintain the overall structure and avoid further damage; at the same time, multiple reinforcing ribs 4 also thicken the sleeve body 10, increasing the screw insertion torque and enhancing the gripping force with the bone channel.

[0042] Furthermore, the surface of the monofilament 13 is provided with a directional resistance-enhancing structure. This directional resistance-enhancing structure includes at least one of barbs, herringbone patterns, or directional rough textures. The barbs can be arranged spirally, in a ring, or with unidirectional oblique teeth. This asymmetric microstructure achieves a "unidirectional resistance-enhancing" mechanism: when its structural direction is consistent with the implantation direction, the microstructure is flattened or slides across the bone wall with minimal resistance, not affecting screw insertion; however, when subjected to pull-out force, the microstructure embeds itself into the trabeculae or bone tunnel wall like a barb, producing a significant mechanical anchoring effect and greatly improving pull-out resistance.

[0043] Furthermore, referring to Figure 1 as well as Figure 7 The first end 11 is a convergent and closed end with a circular cross-section. The single filaments converge from the beginning to the closing point, without sticking together, and the convergence length is 3-10mm. The closing method can be one of heat fusion, adhesive bonding, ultrasonic welding, or sleeve binding. This closing structure can stably fit on the tip of the screw, preventing the sleeve body from slipping during implantation. At the same time, the small diameter of the closing end allows it to smoothly enter the pre-drilled hole. The circular cross-section of the closing end wraps around the screw tip during implantation, avoiding additional damage to the bone tunnel caused by scattered wire ends and screw tips. When screwed in, the closing end generates circumferential compressive stress on the cancellous bone area, improving the initial stability and pull-out resistance of the screw.

[0044] The braiding angle between the monofilament 13 and the sleeve body 10 along the axis is approximately 30-50 degrees. The maximum braiding angle is generally determined by the thick monofilament 21. When the monofilament is thicker, the braiding angle is generally smaller.

[0045] The final diameter of the sleeve body 10 is obtained by heat setting, with a diameter range of 6.5-8.5mm, and the length can be cut arbitrarily, generally 80-160mm; among them, the sleeve body with a diameter of 6.5mm is suitable for internal implants with a diameter of 3.5-6.5mm, and the sleeve body with a diameter of 8.5mm is suitable for internal implants with a diameter of 6.5-10.5mm.

[0046] The material of monofilament 13 has good thermoplasticity and can be selected from polyethylene terephthalate (PET), polyamide (PA, such as nylon 6, nylon 66), polypropylene (PP) and thermoplastic polyurethane (TPU), etc. It can be an absorbable material (such as PLLA, magnesium alloy) or a non-absorbable material (such as PEEK, titanium wire, polymer fiber).

[0047] Furthermore, the implants that the device is compatible with are not limited to traditional screws, but can also be interface screws, locking screws, compression screws or bone plugs, etc.

[0048] Example 2 Reference Figure 3 This embodiment provides a bone canal reinforcement system, including an enhanced pointed bone canal braided cage device 1 as described in Embodiment 1 and a bone screw 200. The device 1 is used for pre-insertion into the bone canal. The bone screw 200 is screwed into the cavity of the pointed bone canal braided cage device 1, such that the device 1 is positioned between the bone screw 200 and the bone canal wall to form a mechanically interlocking structure that provides interfacial resistance. The convergent closing end of the pointed bone canal braided cage device 1 is used to receive the tip of the bone screw. The bone screw 200 includes one of an interface screw, a locking screw, a compression screw, or a bone plug.

[0049] Example 3 Reference Figure 11 This embodiment provides a method for manufacturing an enhanced pointed bone channel woven cage device 1 as described in Embodiment 1, including the following steps: S1: Provide at least two sets of monofilaments 13 with different stiffness; S2: Arrange the at least two sets of monofilaments 13 at intervals and weave them in a spiral cross-braid along the forward and reverse directions of the axial direction to form a long tubular braided structure with a mesh structure; S3: Cut the woven structure and form a gathered and closed end at one end; S4: Heat-set the woven structure after cutting and closing to obtain the enhanced pointed bone channel woven cage device.

[0050] Furthermore, the preparation of the monofilament includes granule drying, melt extrusion, cooling and stretching molding, and multi-stage hot stretching and shaping steps.

[0051] Furthermore, a braiding machine is used for cross-weaving, and the weaving texture is controlled by selecting yarn carriers at different positions: when the yarn carriers are evenly spaced in both directions, a single-layer weaving structure is formed; when the yarn carriers are unevenly spaced in both directions, a double-layer nested weaving structure is formed.

[0052] Furthermore, during the weaving process, reinforcing ribs 4 are placed at the pre-reserved holes in the weaving disc, so that the reinforcing ribs 4 are incorporated into the monofilament cross structure as the weaving process progresses.

[0053] Furthermore, by setting different weave counts (PPI) in segments, weave density zones with varying density along the axial direction are formed.

[0054] Furthermore, the heat setting step includes: fitting the cut and closed woven structure into a heat setting fixture and holding it at a temperature close to the heat distortion temperature of the monofilament material for 15-30 minutes.

[0055] The following is a detailed explanation of the manufacturing method of the enhanced pointed bone channel woven cage device 1: (I) Preparation of monofilaments This embodiment uses medical-grade polyethylene terephthalate (PET) granules as an example, and the specific preparation process is as follows: The production environment must be dust-free and sterile, at least a Class 100,000 cleanroom. First, the medical-grade PET granules are placed in a vacuum dehumidifying dryer and pre-crystallized at 150-160℃ for 40-60 minutes to prevent sticking during drying. Then, the temperature is adjusted to 165-175℃ and drying continues for 4-6 hours, strictly controlling the granule moisture content to not exceed 50ppm. Excessive temperature during this process can easily lead to thermal degradation of the granules, while insufficient drying at excessively low temperatures can easily cause hydrolysis, fiber breakage, and a sudden drop in strength.

[0056] The process then proceeds to the monofilament melt extrusion stage, using a dedicated single-screw extruder with a length-to-diameter ratio of 30:1-36:1 and a compression ratio of 2.5:1-3.0:1. The temperature gradients in each zone of the screw are set as follows: feed section 250-260℃, compression section 265-275℃, metering section 270-280℃, with the die temperature kept constant at 280-290℃ and the melt pressure at 5-15MPa, with fluctuations not exceeding ±0.5MPa. This stage requires gradient heating and precise temperature control to ensure more complete plasticization of the granules. After impurities are removed by a 5-10μm precision filter, the melt is delivered under stable pressure by a high-precision gear metering pump. The pump speed is controlled at 5-30rpm to ensure that the melt flow error does not exceed ±1%, guaranteeing stable filament output and ensuring stable feeding into the spinneret assembly.

[0057] Precise control of monofilament diameter relies primarily on the coordinated operation of metering pump speed, screw extrusion pressure, and traction rate, with fine-tuning of these parameters to achieve high-precision control of the monofilament diameter within ±0.005mm. Medical monofilament spinnerets typically use single-orifice spinnerets: 0.15-0.25mm spinnerets are used for fine denier monofilaments (0.10-0.25mm), and 0.30-0.60mm spinnerets are used for coarse denier monofilaments (0.30-1.00mm). When preparing irregularly shaped monofilaments, the corresponding orifice type of spinneret is directly replaced, with an orifice length-to-diameter ratio of 10:1-20:1 to ensure uniform melt extrusion molding.

[0058] After the melt is extruded through a spinneret, it is cooled and shaped using a constant temperature side-blowing airflow at 18-25℃ and a traction speed of 10-50m / min to form the initial filament. It then undergoes a three-stage hot stretching process: the first stage is multi-stage stretching at 80-120℃, with a total stretch of 3.5-5 times, to improve the breaking strength of the monofilament; the second stage is heat setting at 160-180℃ for 10-30 seconds to reduce the shrinkage rate of the monofilament and stabilize its structural dimensions before winding. Finally, the wound monofilament undergoes post-processing, including surface directional roughness preparation using laser micro-etching or barbing cutting of the monofilament surface using barbing equipment.

[0059] In the monofilament production process, the moisture content of the granules, the extrusion temperature gradient, the metering pump pressure stabilization accuracy, the stretch ratio, and the heat setting parameters are the core factors affecting the mechanical properties and diameter uniformity of the monofilament. Through multi-parameter synergistic optimization, medical-grade PET monofilaments with a breaking strength of not less than 5.0 cN / dtex, a diameter deviation of no more than 0.02 mm, stable mechanical properties, and uniform post-treatment are finally obtained, laying the foundation for the performance of the subsequent woven cage products.

[0060] (II) Weaving and shaping of the cage body Prepared medical-grade PET monofilaments are selected, including coarse monofilaments (0.25-0.40mm in diameter) and fine monofilaments (0.10-0.25mm in diameter). The equipment is a 120-spindle high-speed braiding machine, which is equipped with 60 four-groove impellers and 120 yarn carriers (spindles), of which 60 spindles rotate forward and 60 spindles rotate in reverse. The specific braiding process is as follows.

[0061] First implementation method: Single-layer 2-press 2-weave structure Reference Figure 8 Forty yarn carriers were selected, including 20 forward-rotating spindles and 20 reverse-rotating spindles, with two empty spindles between each selected spindle in each direction. The coarse and fine monofilaments were wound separately to the same length, forming 20 coarse monofilament spindles and 20 fine monofilament spindles. The coarse and fine monofilaments were then alternately arranged on the 40 selected yarn carriers in the same direction to ensure uniform monofilament tension.

[0062] Reference Figure 8 as well as Figure 9 After the equipment is started, all selected spindles move along a fixed circular track in a "planetary gear" motion, with forward and reverse spindles moving alternately in opposite directions. All spindles move around the central weaving disc, and the monofilaments move synchronously with the spindle trajectory. During the weaving operation, the monofilaments carried by the forward-rotating spindles pass under the two oncoming reverse spindles carrying monofilaments, and then pass over the next set of two oncoming reverse spindles carrying monofilaments; the reverse spindles do the same, and so on, forming a "downward-upward" alternating 2-press 2-single-layer weaving structure, ensuring that the monofilaments are tightly crossed and evenly distributed.

[0063] Reference Figure 10 Each impeller 80 has a core wire pre-drilled hole at its center. Taking the braiding disc as a reference, 2-6 pre-drilled holes are evenly selected on the large disc as the placement positions for the reinforcing ribs 4. The reinforcing ribs 4 do not participate in the above-mentioned monofilament braiding trajectory, but only merge into the monofilament cross structure synchronously with the braiding process. They are tightly wrapped by the single-layer braided monofilaments, realizing the design of diverse device structures.

[0064] Second implementation method: Double-layer 2-press 2-nested braided structure Forty-eight yarn carriers were selected, with 24 spindles for forward rotation and 24 for reverse rotation. The spindles were selected to hold the yarn according to a pattern of "1, 2, 1, 2..." Due to the uneven arrangement, they can be considered as being distributed onto two concentric, independent circular tracks. The first layer has 24 spindles (12 for forward rotation and 12 for reverse rotation), with each spindle in the same direction spaced 4 empty spindles apart, performing independent 2-press 2-weave operations. The second layer follows the same principle, ultimately achieving a double-layered, nested braided sleeve body 10a. Reinforcing ribs 4 are embedded between the double-layered braided structures and tightly clamped by monofilaments, further enhancing the structural stability of the finished product.

[0065] In the two embodiments described above, the weaving ratio of thick and thin monofilaments, the position of the spindles, and the arrangement of reinforcing ribs can be flexibly combined as needed to realize the single and double layer structure process design of the device.

[0066] (III) Precise adjustment of weaving parameters To achieve the desired density zoning of the woven cage and control the height of the inner and outer protrusions to meet medical needs, the core weaving parameters are precisely adjusted based on the operating principle of the aforementioned 120-spindle high-speed weaving machine, as follows: Firstly, the PPI (pixel count) adjustment: PPI is the number of weave points per unit length. The higher the value, the tighter the weave, the smaller the spacing between filaments, and the larger the weave angle; the lower the value, the sparser the weave, the larger the spacing between filaments, and the smaller the weave angle. Generally, the PPI setting range is 10-50. Different PPI values ​​and corresponding segment lengths can be set in sections as needed. Through segmented adjustment, the density of different areas of the woven cage can be divided and continuous weaving can be achieved, while precisely controlling the overall length of the finished product.

[0067] Secondly, the tension adjustment of the yarn carrier spring: The tension directly affects the stability and forming effect of monofilament weaving. For coarse monofilaments (0.25-0.40mm in diameter), a coarse spring with a diameter of 0.6-0.8mm is selected. The greater the spring tension, the better the clamping effect on the coarse monofilament and the control of the weaving trajectory, which can reduce monofilament deviation. For fine monofilaments (0.10-0.25mm in diameter), a fine spring with a diameter of 0.4-0.6mm is selected to match the toughness of the fine monofilament, avoid excessive tension that may cause monofilament breakage, and ensure the stability of the weaving process.

[0068] Thirdly, the size adjustment of the central braiding mandrel: The mandrel is located at the point where the monofilaments converge on the central braiding disc, and it directly determines the initial braiding diameter of the long strip structure. Based on the finished product's dimensions, a mandrel with a diameter of 4-6mm is selected, slightly smaller than the final finished product diameter (6.5-8.5mm). Because monofilaments are tough, the physically cross-pressed braiding structure itself is unstable. The mandrel guides the monofilament braiding, maintains the hollow cavity in the sleeve, and simultaneously reserves reasonable space for subsequent heat setting.

[0069] Fourth, adjustment of the height difference of the protrusions: The difference in monofilament diameter directly determines the height difference of the protrusions inside and outside the woven cage. The greater the difference in the diameter of the selected thick and thin monofilaments, the more obvious the height difference of the undulations after weaving. When the thin monofilament is pressed on the thick monofilament, the thin monofilament will be passively bent, forming a significant protrusion. That is, the undulations on the inner and outer surfaces of the device are more obvious. The rougher the surface, the stronger the anchoring of the bone channel. The wire diameter can be flexibly selected according to the protrusion requirements of the finished product.

[0070] (iv) Cutting, sealing and heat setting The long strips of woven structure removed from the braiding machine need to undergo subsequent processes such as cutting and heat setting to ensure that the finished structure is sturdy and dimensionally stable, meeting the requirements for medical implantation and surgical use. The specific processes are as follows: The first step is cutting and sealing: The woven strip structure is cut to the required length for medical use. Before cutting, the individual filaments at the cut ends are gathered together and sealed using heat-melting, adhesive bonding, or ultrasonic melting to form a circular cross-section. This sealing structure effectively prevents the device from being punctured by screw tips or other implanted instruments during surgery, ensuring surgical safety and device integrity.

[0071] The second step is the core heat-setting process: the cut and closed braided structure is fitted into a heat-setting fixture, which is a smooth stainless steel cylindrical rod. During fitting, the braided structure expands radially and tightens, tightly fitting the surface of the fixture. The diameter of the fixture determines the final inner diameter of the finished product, and the outer diameter of the braided structure after setting is the standard diameter of the finished product. The closed end of the braided structure is bound with a 3-10mm long sleeve at a 90° angle, and the structure is placed together with the heat-setting fixture in a hot oven to set its shape (see [link]). Figure 6 , Figure 7 ).

[0072] The temperature of the hot drying oven is generally set close to the heat distortion temperature of PET, and the holding time is controlled between 15-30 minutes. During this process, under the combined action of heat and radial tension, the PET monofilaments release the internal stress generated during weaving, and the molecular chain segments relax and rearrange, adapting to and "memorizing" the current state fixed by the shaping fixture and sleeve, tightly adhering to the fixture and sleeve structure. After cooling, the movement of the PET monofilament molecular chain segments is "frozen," and the weaving structure changes from a metastable state to a new stable state with stable dimensions, permanently maintaining the weaving shape, without shrinkage, and the height of the inner and outer protrusions and the pointed structure are all fixed; when the ambient temperature is not higher than the heat distortion temperature of PET, the device will not undergo irreversible deformation.

[0073] The finished product specifications are compatible as follows: a device with a diameter of 6.5mm is compatible with implants with a diameter of 3.5-6.5mm, and a device with a diameter of 8.5mm is compatible with implants with a diameter of 6.5-10.5mm; the implants are not limited to screws, but may also include nails, rods or other medical implants that are partially implanted in the bone.

[0074] (v) How to use the device Measure the length of the screw to be implanted from the closed end of the device and mark a line; then cut the device along the marked line, but not completely cut it off, leaving a few monofilaments; next, hold the device remnant and push it into the bone tunnel with a push rod; then screw the bone screw into the device; finally, cut off the remaining monofilaments to complete the implantation of the device.

[0075] (vi) Mechanical property verification Reference Figure 12 And the table below shows a comparison of mechanical amplification before and after using the device of the present invention under simulated osteoporosis conditions (distinguished by different bone densities).

[0076]

[0077] The device simulates bone density of poor bone quality at 20 pcf and normal bone density at 40 pcf. Under the same drilling conditions, the pull-out force increase is comparable for normal bone and weak bone after using the device of this invention, with the increase for weak bone even exceeding that for normal bone.

[0078] Reference Figure 13 The simulation shows the effect of different structural devices on the pull-out force of screws under the same bone density, bone screws, and pre-drilled conditions: the pull-out force is significantly increased when using the device of the present invention compared to using only screws to insert into the bone channel; the pull-out force of the structure with sparse and dense partition design is slightly greater than that of the unpartitioned design; the clamping of the reinforcing ribs further improves the pull-out force.

[0079] Reference Figure 14The diagram shows a comparison of pull-out resistance of devices constructed from simulated irregular cross-section monofilaments and circular cross-section monofilaments under different bone densities and the same experimental conditions: the device constructed from barbed irregular cross-section monofilaments has a pull-out resistance that is about 10% higher than that of the circular cross-section monofilament.

[0080] Reference Figure 15 The invention demonstrates a mechanical comparison of reinforcement using the original-size bone screw and reinforcement using the original-size bone screw in conjunction with the device of the present invention under simulated normal drilled screw reinforcement scenarios (drilled hole 3.5mm) and reaming scenarios (reamed hole drilled 4.0mm). By enlarging the pre-drilled hole to simulate the situation where reaming is required after normal bone screw reinforcement fails, without replacing with a larger and thicker screw, when the original bone screw can continue to be used or a screw of the same size as the original screw is available, the mechanical data after using the device of the present invention can basically restore the effect of normal drilled screw reinforcement.

[0081] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which shall be within the scope of protection of the invention.

Claims

1. An enhanced pointed-head woven cage device, characterized in that, The device includes a long, tubular sleeve body with a cavity; the sleeve body is elastically expandable and contractable along the axial and radial directions, and is made of at least two sets of monofilaments with different rigidities woven together to create a mesh structure; the sleeve body includes a first end and a second end in opposite directions, the first end being a closed end for receiving the end of a bone screw; the second end being an open end serving as the insertion port for the bone screw; the device is used to pre-insert into a bone tunnel and, after the bone screw is screwed in, is positioned between the bone screw and the wall of the bone tunnel to form a mechanically interlocking structure that provides interfacial resistance; the sleeve body is provided with weaving density zones of varying density along the axial direction to adapt to bone tissue with uneven density along the vertical direction of the bone structure.

2. The reinforced pointed bone channel woven cage device according to claim 1, characterized in that: The at least two sets of monofilaments with different rigidities include at least two sets of monofilaments with different sizes, and the at least two sets of monofilaments with different rigidities are arranged alternately and woven in a cross-helical pattern.

3. The enhanced pointed bone channel woven cage device according to claim 2, characterized in that: The at least two sets of monofilaments of different sizes include a coarse monofilament set and a fine monofilament set. The coarse monofilament set includes multiple coarse monofilaments that are spirally interwoven in both directions along the axis of the sleeve body. The fine monofilament set includes multiple fine monofilaments that are spirally interwoven in both directions along the axis of the sleeve body. The coarse monofilaments and the fine monofilaments are arranged alternately.

4. The enhanced pointed bone channel woven cage device according to claim 3, characterized in that: Multiple protrusions are formed at the intersection of the monofilaments, and the protrusions are distributed on the inner and outer surfaces of the sleeve body.

5. The reinforced pointed bone channel woven cage device according to claim 4, characterized in that: The diameter of the coarse monofilament is in the range of 0.25-0.40 mm, the diameter of the fine monofilament is in the range of 0.10-0.25 mm, and the thickness of the protrusion is 0.20-0.80 mm.

6. The reinforced pointed bone channel woven cage device according to claim 1, characterized in that: The cross-section of the closed end is circular, and the closing method is one of hot melting, adhesive bonding, ultrasonic welding or sleeve binding, with a closing length of 3-10mm.

7. The reinforced pointed bone channel woven cage device according to claim 1, characterized in that: At least one reinforcing rib is also inserted into the sleeve body. The reinforcing rib is distributed along the axial direction of the sleeve body to withstand the cutting of bone screws and maintain the structural integrity of the sleeve body.

8. The enhanced pointed bone channel woven cage device according to claim 7, characterized in that: The number of reinforcing ribs is 2-6, which are sandwiched in the middle of the double-layer woven structure, or merged into the single-layer woven structure as the weaving process progresses.

9. The reinforced pointed bone channel woven cage device according to claim 1, characterized in that: The surface of the monofilament is provided with a directional resistance-enhancing structure, which includes at least one of barbs, herringbone patterns, or directional rough textures.

10. The reinforced pointed bone channel woven cage device according to claim 9, characterized in that: The barbs are arranged in a spiral, a ring, or a unidirectional oblique tooth arrangement.

11. A bone canal reinforcement system, characterized in that, The device includes the enhanced pointed bone tunnel braided cage device and bone screw as described in any one of claims 1 to 10, wherein the device is for pre-insertion into the bone tunnel, and the bone screw is for screwing into the cavity of the device, such that the device is positioned between the bone screw and the wall of the bone tunnel to form a mechanical interlocking structure that provides interfacial resistance.

12. A method for manufacturing an enhanced pointed-head woven cage device, characterized in that, Includes the following steps: S1: Provide at least two sets of monofilaments with different stiffness; S2: Arrange the at least two sets of monofilaments at intervals and weave them in a spiral cross-braid along the forward and reverse directions of the axial direction to form a long tubular braided structure with a mesh structure; S3: Cut the woven structure and form a gathered and closed end at one end; S4: Heat-set the woven structure after cutting and closing to obtain the enhanced pointed bone channel woven cage device.

13. The method for manufacturing the enhanced pointed bone channel woven cage device according to claim 12, characterized in that: During the weaving process, reinforcing ribs are placed at the pre-reserved holes in the weaving disc, so that the reinforcing ribs are incorporated into the monofilament cross structure as the weaving progresses.

14. The method for manufacturing the enhanced pointed bone channel woven cage device according to claim 12, characterized in that: By setting different weave counts in segments, weave density zones with varying density along the axial direction are formed.

15. The method for manufacturing the enhanced pointed bone channel woven cage device according to claim 12, characterized in that: Step S4 involves heat-setting the cut and closed woven structure, including: fitting the cut and closed woven structure into a heat-setting fixture and holding it at a temperature close to the heat distortion temperature of the monofilament material for 15-30 minutes.

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