An auxiliary instrument for intraoperative shaping and delivery of a talar component

Abstract

The application discloses an auxiliary instrument for shaping and delivering accessory navicular bone in operation, and belongs to the field of foot and ankle surgical instruments, and aims to solve the problems of autologous waste bone waste in accessory navicular bone resection, the need for secondary bone removal for same-table bone grafting, the lack of local anatomical protection for general instruments, and the insufficient precision of bone block shaping and delivery. The instrument comprises a posterior tibial tendon insertion point separator, a small bone block shaping device, a delivery positioner and a delivery rod; the separator is provided with an insertion point guard and a blunt separation structure, which can protect the posterior tibial tendon insertion point and the medial dorsal cutaneous nerve; the shaping device is provided with a replaceable lining, which can compact the accessory navicular bone into a shaped bone block with a controllable shape; the delivery positioner is provided with a retaining structure, which cooperates with the delivery rod to complete accurate delivery and positioning of the bone block. The application can utilize autologous waste bone for bone grafting on site, avoid secondary bone removal damage, protect the surrounding anatomical structure throughout the operation, and is accurate and efficient.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to an auxiliary device for shaping, modifying, and delivering accessory navicular bones during surgery. Background Technology

[0002] Accessory navicular bones are common, independent ossification centers on the proximal medial side of the navicular bone in the foot, to which the tibialis posterior tendon attaches. For symptomatic accessory navicular bones, clinical treatment often involves accessory navicular bone resection (including the classic Kidner procedure, the modified Kidner procedure, and simple resection). During the procedure, the medial naviculoplasty is usually simultaneously smoothed to eliminate the local bony prominence. Currently, in routine clinical practice, the surgically removed accessory navicular bone and the resulting medial navicular bone fragments are discarded directly as medical waste.

[0003] For patients with severe rigid flat feet, hindfoot arthritis, or other conditions, hindfoot joint fusion (subtalar, talonavicular, or calcaneocuboid joint fusion) or medial column augmentation surgery is often performed concurrently with accessory navicular bone resection. All of these surgeries require sufficient bone graft material to ensure fusion effectiveness and orthopedic stability. Currently used bone graft materials have significant drawbacks: First, autologous iliac bone transplantation adds donor site damage to the existing foot surgical trauma, prolonging surgery time and potentially causing complications such as donor site pain, bleeding, and infection; second, allogeneic bone carries risks of disease transmission and immune rejection, and its osteoinductive activity is limited; third, synthetic bone substitutes are expensive, and some patients experience poor osseointegration and foreign body reactions.

[0004] In terms of bone tissue processing instruments, existing general-purpose bone grinders can only grind bone tissue into loose bone particles, and cannot compress small-volume, irregularly shaped accessory navicular bones into shaped bone blocks with precise control over their dimensions and retaining the complete bone block structure; loose bone particles are easily lost during bone grafting and have poor support, making it difficult to meet the structural support requirements of medial column elevation and the precise fitting requirements of hindfoot fusion surface.

[0005] Meanwhile, the accessory navicular region has a complex anatomy, adjacent to the insertion point of the posterior tibialis tendon and the medial dorsalis pedis cutaneous nerve branch. During the surgical dissection, trimming, and bone graft delivery process, sharp contact of instruments can easily cause tendon insertion tears and cutaneous nerve damage, leading to postoperative complications such as weakened posterior tibialis tendon function and numbness of the medial skin of the foot. Currently used general-purpose periosteal elevators and bone graft delivery devices are all of general design and do not have dedicated protective structures for the special anatomy of the accessory navicular region. They are highly dependent on the surgeon's experience, and manual trimming of bone blocks and placement of bone graft materials are inaccurate, time-consuming, and make it difficult to ensure the accuracy of bone graft placement and the suitability of bone block morphology.

[0006] In summary, the current clinical practice lacks dedicated instruments for accessory scaphoid resection, making it impossible to achieve integrated operation that combines on-site reshaping of autologous waste bone, precise protection of surrounding anatomical structures, and accurate delivery and positioning of bone grafts. This makes it difficult to ensure surgical safety and bone grafting effectiveness while avoiding secondary bone harvesting. Summary of the Invention

[0007] This invention provides an auxiliary instrument for shaping, modifying, and delivering accessory navicular bones during surgery. It can solve the current clinical problems of lacking dedicated instruments for accessory navicular bone resection and the difficulty in ensuring surgical safety and bone grafting results while avoiding secondary bone harvesting.

[0008] To achieve the above objectives, the present invention provides the following technical solution: an auxiliary device for shaping and delivering accessory navicular bones during surgery, comprising: a posterior tibialis tendon insertion separator, the posterior tibialis tendon insertion separator comprising a first handle portion and a distal working head disposed at one end of the first handle portion, the distal working head being boot-shaped, an insertion guard being disposed at the distal lower edge of the distal working head, and a blunt blade assembly being disposed on the side wall of the distal working head above the insertion guard. The small bone block remodeling molding device includes a first clamp and a second clamp, the middle of which are connected by a pivot point. One end of each of the first and second clamps is provided with a molding block. Molding inner liner blocks can be detachably installed on opposite sides of the two molding blocks. When the molding inner liner blocks are joined together, a molding cavity is formed on the inner side. The molding cavity is configured to mold the accessory navicular bone into a hindfoot bone graft or a medial column for elevation. A delivery locator, comprising a second handle portion and a blunt-ended delivery head having the distal end of the second handle portion, wherein the blunt-ended delivery head is provided with a retention structure for limiting the placement of the molded bone block. Delivery rods are used to push and push molded bone blocks from the fixation structure to the hindfoot fusion surface or medial column padding site.

[0009] The above four instruments can be used together to complete the entire procedure in the same surgery, eliminating the need to assemble multiple general-purpose instruments, simplifying the surgical procedure and shortening the operation time. The guard and blunt edge design of the posterior tibial tendon insertion separator and the blunt end design of the delivery device form a complete protection system, providing physical protection for the tendon and nerve throughout the entire process from bone stripping to bone graft delivery, significantly reducing the risk of complications.

[0010] Preferably, the molded inner liner block includes an outer shell and an inner molded sidewall. The outer shell includes a bottom plate and a side plate connected to the molded block, and an elastic body is provided between the side plate and the inner molded sidewall.

[0011] Preferably, a positioning pin for insertion into the accessory navicular bone is installed on the base plate of any of the molded inner liner blocks.

[0012] Preferably, the base plate is provided with a plurality of elongated overflow chip discharge grooves near the inner forming sidewall.

[0013] Preferably, the proximal end of the first handle of the posterior tibial tendon insertion separator is provided with a negative pressure tube interface, and a suction port is provided on the side wall of the distal working head between the insertion guard and the blunt blade assembly. The suction port and the negative pressure tube interface are connected through a channel inside the first handle and the distal working head.

[0014] Preferably, the blunt edge group includes three blunt edges whose height increases sequentially from the distal end to the proximal end, forming a stepped layered structure, and the cutting edges of the blunt edges are all blunt rounded corners.

[0015] Preferably, the upper edge of the stop guard is provided with a raised limiting ridge, which extends along the arc of the stop guard.

[0016] Preferably, a flexible wing extends from each of the left and right sides of the distal working head, and the flexible wing curves upward toward the dorsum of the foot.

[0017] Preferably, the delivery rod includes a rod body and a ball disposed at the end of the rod body.

[0018] Preferably, the retaining structure includes a retaining groove for retaining the molded block and a plurality of clamping arms located on both sides of the retaining groove. The clamping arms are springs, one end of which is fixed to the blunt end delivery head, and the other end of which extends above the retaining groove.

[0019] Compared with the prior art, the beneficial effects of the present invention are: This instrument can transform autologous accessory scaphoid bone and scaphoid bone fragments that should be discarded during accessory scaphoid resection into shaped bone blocks for bone grafting on-site, eliminating the need for donor site damage from secondary bone harvesting from sites such as the iliac bone. It also avoids the risk of immune rejection and foreign bodies associated with allogeneic bone and artificial bone substitutes, and the osteogenic activity of autologous bone tissue is superior.

[0020] The clamp-type molding device, paired with replaceable inner liner blocks, can compact irregular small bone blocks into structured bone blocks whose shape and size are precisely adapted to the bone graft site, preserving the complete bone block structure rather than loose particles; the positioning pin pre-fixation, elastomer buffer, and overflow chip removal groove work together to ensure that the bone block is subjected to uniform force, formed regularly, and not easily broken, and can adapt to different shape requirements of hindfoot bone graft and medial column elevation.

[0021] The separator's stop guard, stepped blunt edge, and flexible flanks physically isolate and protect the posterior tibial tendon insertion and the medial dorsalis pedis cutaneous nerve. The delivery device features a fully blunt edge design, which significantly reduces the risk of sharp injury during surgery and minimizes postoperative complications.

[0022] The delivery locator's spring-loaded retaining structure can stably support the bone block, and together with the ball-shaped delivery rod, it can smoothly push the bone block, making it less likely to shift or fall out, and ensuring high precision in bone graft placement. The entire instrument process is seamless and coordinated, which can shorten operation time and reduce surgical difficulty. Attached Figure Description

[0023] Figure 1 This is a front view of the posterior tibial tendon insertion separator of the present invention. Figure 2 This is a cross-sectional view of the posterior tibial tendon insertion separator of the present invention. Figure 3 This is a side view of the posterior tibial tendon insertion separator of the present invention. Figure 4 This is a front view structural diagram of the small bone block modified molding device of the present invention; Figure 5 This is a cross-sectional view of the small bone block modified molding device of the present invention; Figure 6 This is a structural diagram of the delivery locator of the present invention; Figure 7 This is a structural diagram of the delivery rod of the present invention.

[0024] Figure label: 1. Posterior tibialis tendon insertion separator; 2. Delivery locator; 3. Small bone block remodeling molding device; 4. Delivery rod; 11. First handle part; 12. Negative pressure tube interface; 13. Distal working head; 14. Flexible side wing; 15. Insertion guard support; 16. Limiting ridge; 17. Blunt blade assembly; 18. Channel; 19. Suction port; 21. Second handle part; 22. Blunt end delivery head; 23. Fixing structure; 24. Clamping pressure arm; 31. First clamping body; 32. Second clamping body; 33. Rotation fulcrum; 34. Molding block; 35. Molding inner liner block; 351. Inner molding sidewall; 352. Elastomer; 353. Outer shell; 37. Molding cavity; 38. Positioning pin; 39. Overflow chip removal groove; 41. Sphere; 42. Rod. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0026] like Figure 1-7As shown, this invention addresses the current clinical problem of lacking dedicated instruments for accessory navicular bone resection, making it difficult to ensure surgical safety and bone grafting effectiveness while avoiding secondary bone harvesting. The invention provides the following technical solution: an auxiliary instrument for shaping, modifying, and delivering the accessory navicular bone during surgery, comprising: a posterior tibialis tendon insertion separator 1. The posterior tibialis tendon insertion separator 1 includes a first handle portion 11 and a distal working head 13 disposed at one end of the first handle portion 11. The distal working head 13 is boot-shaped, and an insertion guard 15 is provided at the distal lower edge of the distal working head 13. A blunt blade assembly 17 is provided on the side wall of the distal working head 13 above the insertion guard 15. Small bone block molding device 3 includes a first clamp 31 and a second clamp 32. The middle parts of the first clamp 31 and the second clamp 32 are connected by a rotation fulcrum 33. One end of the first clamp 31 and the second clamp 32 is provided with a molding block 34. Molding inner liner blocks 35 can be detachably installed on opposite sides of the two molding blocks 34. When the molding inner liner blocks 35 are joined, a molding cavity 37 is formed on the inner side. The molding cavity 37 is configured to mold the accessory navicular bone into a hindfoot bone graft or a medial column for elevation. Delivery locator 2, the delivery locator 2 includes a second handle part 21 and a blunt end delivery head 22 provided at the distal end of the second handle part 21, the blunt end delivery head 22 is provided with a fixation structure 23 for limiting the placement of the molded bone block; Delivery rod 4 is used to push out and push the molded bone block on the fixation structure 23 to the hindfoot fusion surface or the medial column pad elevation site.

[0027] Among them, the boot-shaped working head of the posterior tibialis tendon insertion separator 1 is adapted to the anatomical surface of the accessory navicular bone region, and can be smoothly inserted into the narrow soft tissue space; the insertion guard physically isolates the posterior tibialis tendon insertion point from the operating area from below, avoiding direct cutting of the tendon by the osteotome or drill, and greatly reducing the risk of insertion point avulsion; the blunt blade group separates the soft tissue and periosteum by blunt pushing, replacing sharp dissection, which avoids damage to the medial dorsalis pedis cutaneous nerve while efficiently exposing the surgical area, and reduces intraoperative bleeding.

[0028] The clamp-type hinge structure of the small bone block molding device 3 utilizes the lever principle to achieve single-handed operation, with controllable force and suitability for aseptic surgical scenarios; the detachable inner liner block encloses and forms a molding cavity, which can compact irregular accessory navicular bones into structured bone blocks of a preset shape, preserving the integrity of bone tissue and osteoconductive activity, while precisely adapting to the shape of bone graft sites; the replaceable inner liner block design can adapt to different bone block needs such as hindfoot bone grafting and medial column elevation, improving the versatility of the instrument.

[0029] The blunt end of the delivery locator 2 has no sharp edge structure, so it will not scratch soft tissue, tendons and nerves when it is inserted into the surgical area. It can also assist in blunt dissection of the bone graft gap. The fixation structure temporarily limits the shape of the bone block, preventing the bone block from shifting or falling off during delivery, avoiding the bone block falling into the deep part of the surgical area and causing foreign body residue. At the same time, it does not require manual support, reducing the risk of contamination.

[0030] The above four instruments can be used together to complete the entire procedure in the same surgery, eliminating the need to assemble multiple general-purpose instruments, simplifying the surgical procedure and shortening the operation time. The guard and blunt edge design of the posterior tibial tendon insertion separator and the blunt end design of the delivery device form a complete protection system, providing physical protection for the tendon and nerve throughout the entire process from bone stripping to bone graft delivery, significantly reducing the risk of complications.

[0031] In this embodiment, the molded inner liner block 35 includes an outer shell 353 and an inner molded sidewall 351. The outer shell 353 includes a base plate and a side plate connected to the molded block 34. An elastic body 352 is disposed between the side plate and the inner molded sidewall 351. The elastic body 352 fills the space between the outer shell and the inner wall, providing a buffer stroke during compression to avoid bone fragmentation caused by rigid compression. At the same time, the elastic rebound force makes the bone fragment more evenly stressed, improving the molding density. It can also automatically adapt to accessory navicular bones of different volumes within a certain range, improving the device compatibility.

[0032] In this embodiment, a positioning pin 38 for insertion into the sub-navicular bone is installed on the bottom plate of any one of the molding inner liner blocks 35. The positioning pin 38 on one side can be inserted into the sub-navicular bone for pre-fixation to prevent the bone block from sliding and shifting in the mold cavity during clamping, thus ensuring the symmetry of the shape and dimensional accuracy of the bone block after molding. After the bone block is fixed, it will not shift with deformation during elastic buffering and pressing, further improving the molding accuracy.

[0033] In this embodiment, a plurality of elongated overflow chip removal grooves 39 are provided on the base plate near the inner molding sidewall 351. The elongated overflow chip removal grooves 39 can discharge excess bone chips and bone marrow tissue in the mold cavity, avoiding accumulation that could cause the bone block to bulge or exceed dimensional tolerances, thus ensuring the accurate shape of the bone block. The overflow chip removal grooves 39 are located near the inner molding sidewall, so that excess bone chips are discharged evenly along the edge, preventing local defects in the bone block.

[0034] In this embodiment, a negative pressure tube interface 12 is provided at the proximal end of the first handle portion 11 of the posterior tibial tendon insertion separator 1, and a suction port 19 is provided on the side wall of the distal working head 13 between the insertion guard 15 and the blunt blade assembly 17. The suction port 19 and the negative pressure tube interface 12 are connected through a channel 18 inside the first handle portion 11 and the distal working head 13. The negative pressure tube interface 12, the channel 18 and the suction port 19 form a complete suction path, allowing for simultaneous removal of oozing blood, tissue fluid and bone fragments during the dissection operation, maintaining a clear surgical field, eliminating the need for additional suction heads, reducing the number of instruments in the surgical area and minimizing operational interference. The suction port 19 is located between the insertion guard 15 and the blunt blade assembly 17, allowing for precise alignment of the operating area, resulting in high suction efficiency, and preventing the adsorption of tendon and nerve tissue, thus avoiding additional damage.

[0035] In this embodiment, the blunt blade assembly 17 includes three blunt blades with progressively increasing height from distal to proximal. The three blunt blades form a stepped, layered structure, and the edges of the blunt blades are all bluntly rounded. The three blunt blades separate layer by layer in a stepped manner, replacing the single-blade one-time dissection. The separation process is gentler, causes less tissue traction damage, and is easier to control the separation depth, avoiding excessive damage to the periosteum and blood vessels. The blunted edges and rounded corners have no sharp edges, structurally avoiding the risk of cutting tendons and cutaneous nerves.

[0036] In this embodiment, the upper edge of the stop point guard 15 is provided with a raised limiting ridge 16, which extends arc-shaped along the stop point guard 15. The arc-shaped limiting ridge 16 forms a lateral limit at the upper edge of the stop point guard 15, restricting the tendon insertion point within the support area, preventing tendon slippage and exposure during operation, and improving the reliability of protection. The raised structure only serves a limiting function and will not compress the tendon or affect blood supply, thus balancing protection and safety.

[0037] In this embodiment, a flexible wing 14 extends from each of the left and right sides of the distal working head 13, and the flexible wing 14 is curved towards the dorsum of the foot. The flexible wing 14 on both sides is curved towards the dorsal side, which can spread the soft tissue from the side and push away the medial cutaneous nerve of the dorsum of the foot, so that it is away from the operating area, forming lateral physical protection and further reducing the probability of nerve damage. The flexible material can adapt to the tissue shape and will not cause ischemic damage due to rigid compression. At the same time, it reduces tissue friction when the instrument enters and exits, and reduces postoperative edema.

[0038] In this embodiment, the delivery rod 4 includes a rod body 42 and a ball 41 disposed at the end of the rod body 42. The pushing stress is uniform, and it will not puncture brittle bone tissue, thus ensuring the integrity of the bone block structure.

[0039] In this embodiment, the retaining structure 23 includes a retaining groove for retaining the molded block and a plurality of clamping arms 24 located on both sides of the retaining groove. The clamping arms 24 are spring sheets, one end of which is fixed to the blunt end delivery head 22, and the other end of which extends to the top of the retaining groove. The elastic spring sheets can be pushed outward to pick up and put down bone blocks, making the operation convenient. The elastic pressure will not excessively squeeze the bone blocks and cause them to break, which is suitable for the characteristics of brittle bone tissue.

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. Equivalent substitutions and conventional modifications made by those skilled in the art, based on the structural principles disclosed in the present invention, regarding the shape of components and connection methods without inventive effort, all fall within the protection scope of the present invention.

[0041] This embodiment provides an auxiliary instrument for intraoperative shaping, modification, and delivery of the accessory navicular bone. It is a modular surgical instrument set, consisting of four independent instruments: a posterior tibialis tendon insertion separator 1, a small bone fragment shaping device 3, a delivery locator 2, and a delivery rod 4. These four instruments are used in sequence according to the surgical procedure, enabling simultaneous completion of the entire process during accessory navicular bone resection, including soft tissue separation and protection around the accessory navicular bone, on-site shaping and modification of autologous waste bone, and precise delivery and positioning of the shaped bone fragment. All components in contact with human tissue are made of medical-grade 304 stainless steel or medical-grade polymer materials, and can withstand high-temperature and high-pressure steam sterilization, meeting the requirements for aseptic surgery.

[0042] The posterior tibial tendon insertion separator 1 is a long rod-shaped single-headed surgical instrument with an overall axial length of 175mm~185mm. It is divided into a first handle part 11 at the proximal end and a distal working head 13 at the distal end along the axial direction. The two are integrally formed and have a through suction channel inside.

[0043] The first handle section 11 is cylindrical in shape, 110mm in length and 10mm in diameter. Its outer surface is knurled for anti-slip texture, with a knurling depth of 0.3mm and a pitch of 0.8mm, for stable grip by the surgeon. A standard Luer male connector is embedded in the proximal end face of the first handle section 11 as a negative pressure tube interface 12, which can be sealed and connected to a standard negative pressure suction tube in the operating room. An axially oriented through channel 18 is machined inside the first handle section 11. The channel 18 has a diameter of 3mm and a smooth, stepless inner wall. The proximal end of the channel 18 connects to the negative pressure tube interface 12, and the distal end extends into the distal working head 13.

[0044] The distal working head 13 is integrally connected to the distal end of the first handle portion 11. It is 70 mm long and gradually narrows from proximal to distal, forming a boot-shaped structure that conforms to the anatomical curvature of the medial side of the navicular bone. Its maximum width is 12 mm, minimum width is 6 mm, and thickness is 4 mm, allowing it to easily extend into the narrow soft tissue spaces surrounding the accessory navicular bone. All exposed edges of the distal working head 13 are rounded with a radius of 0.5 mm, eliminating sharp edges.

[0045] The insertion point guard 15 is integrally formed on the lower edge of the sole of the foot at the farthest end of the distal working head 13. It has an upward-curving arc-shaped support structure with an arc length of 8mm, a width of 6mm, and a thickness of 1mm. The upper surface of the insertion point guard 15 is a smooth concave arc surface with a curvature that matches the anatomical shape of the lower edge of the tibialis posterior tendon insertion point. During operation, it is lifted below the tibialis posterior tendon insertion point to form a physical isolation barrier, preventing the osteotomy and dissection instruments from directly contacting and damaging the tendon insertion point.

[0046] The limiting ridge 16 is integrally raised on the upper edge of the stop guard 15, extending along the entire arc of the stop guard 15, with a ridge height of 0.8mm and a rounded top. The limiting ridge 16 forms a lateral limiting structure towards the tendon side to prevent the posterior tibial tendon insertion from slipping off the surface of the stop guard 15 during operation.

[0047] The blunt-blade assembly 17 is located on the anterior sidewall of the distal working head 13 above the stop guard 15. It consists of three parallel blunt separation ridges, with the height of the three separation ridges increasing sequentially from distal to proximal. The spacing between adjacent ridges is 2 mm, and the height difference is 0.5 mm, forming a stepped layered separation structure. The edges of each separation ridge are rounded to R0.4 mm, without a cutting edge, and are used for blunt dissection of the periosteum and soft tissue adhesions on the surface of the accessory navicular bone layer by layer, avoiding sharp cutting damage to surrounding tissues.

[0048] The suction port 19 is located on the side wall of the distal working head 13 between the stop guard 15 and the blunt blade assembly 17. It is an elongated through hole, 6mm long and 2mm wide, with the inner edge of the hole rounded. The suction port 19 is connected to the internal channel 18. After the negative pressure is connected, the bleeding, small bone fragments and tissue fluid generated during the separation operation can be accurately suctioned out, keeping the surgical field clear.

[0049] Two flexible wing 14 pieces are provided, respectively bonded and fixed to the left and right side walls of the distal working head 13. They are made of medical-grade thermoplastic polyurethane material with a thickness of 0.3 mm. Each flexible wing 14 is curved 15° from the side wall of the working head towards the dorsum of the foot, with a single-sided unfolding width of 3 mm. The flexible wing 14 can adaptively conform to the surrounding soft tissue, opening and pushing the medial dorsum of the foot cutaneous nerve branch from the side, avoiding direct friction and compression of the nerve by the instrument during operation, thus preventing damage.

[0050] The small bone block molding device 3 is a clamp-type lever compaction structure with an overall axial length of 155mm~165mm. It includes a first clamp 31 and a second clamp 32. The middle parts of the first clamp 31 and the second clamp 32 are hinged through a rotation fulcrum 33 to form a force-saving lever structure.

[0051] The first clamping body 31 and the second clamping body 32 are symmetrically structured, with the pivot point 33 as the boundary. The proximal end is the operating arm, and the distal end is the shaping arm. The operating arm is 90mm long and has a closed finger ring at the end with an inner diameter of 20mm, suitable for the operator's fingers to insert and grip. The outer surface of the operating arm has an anti-slip texture. The pivot point 33 is a 3mm diameter stainless steel hinge pin. The pin is clearance-fitted with the shaft hole of the clamping body to ensure smooth and jam-free clamping action.

[0052] A rectangular forming block 34 is fixedly installed at the end of the forming arm of both the first clamping body 31 and the second clamping body 32, and is integrally formed with the corresponding clamping body. A dovetail-shaped groove running through the width direction is machined on the opposite sides of each of the two forming blocks 34 for detachable installation of the forming inner liner block 35. Two positioning pins are provided at diagonal positions on one side of the forming block 34, and positioning holes are provided at corresponding positions on the other side of the forming block 34. When clamped, the positioning pins are inserted into the positioning holes to ensure precise alignment of the two sides.

[0053] Two molding liner blocks 35 are provided, which are respectively snapped into the slots of the molding blocks 34 on both sides. The two molding liner blocks 35 together form a compaction molding unit. The molding liner block 35 is rectangular in shape to fit the molding block 34, with a thickness of 4mm on one side. It can be inserted and removed along the slot to adapt to the molding requirements of different shaped bone blocks. Each molding liner block 35 consists of three layers from the outside to the inside: an outer shell 353, an elastic body 352, and an inner molding sidewall 351.

[0054] The outer shell 353 is a stainless steel outer structure, including a bottom plate and side plates. The back of the bottom plate is provided with a dovetail tenon that matches the slot. The dovetail tenon is inserted into the slot of the forming block 34 to achieve a detachable connection with the forming block 34. The outer shell 353 provides a rigid support reference to ensure that the inner liner block structure does not deform during the clamping process.

[0055] The elastomer 352 is filled between the inner side of the outer shell 353 and the inner molded sidewall 351. It is made of medical-grade silicone rubber with a Shore hardness of 45A and a thickness of 1.5mm. The elastomer 352 provides a buffer stroke during clamping, so that the bone block is subjected to uniform force and avoids bone fragmentation caused by rigid compression. At the same time, it can adaptively fit accessory navicular bone tissue of different volumes.

[0056] The inner molding sidewall 351 is an inner layer structure made of titanium alloy, with a surface polished to Ra0.8μm to reduce bone tissue adhesion. When the two molding inner liner blocks 35 are aligned, the inner molding sidewalls 351 on both sides together form a closed molding cavity 37; in this embodiment, the molding cavity 37 is wedge-shaped to adapt to the shape requirements of the bone block with the inner column raised. By replacing the molding inner liner blocks 35 with different inner contours, molding cavities 37 with different shapes can be obtained to adapt to different surgical scenarios such as hindfoot bone grafting.

[0057] The positioning pin 38 is located at the center of the bottom plate of the molding inner liner block 35 on one side. A stainless steel positioning pin 38 is vertically fixed, with a pin body diameter of 0.8mm, a length of 2.5mm, and a 30° tapered blunt tip. Before the clamping operation, the positioning pin 38 is inserted into the accessory navicular bone to achieve pre-fixation of the bone block, preventing the bone block from sliding and shifting in the molding cavity 37 during the pressing process, and ensuring molding accuracy.

[0058] The overflow chip removal groove 39 is located on the bottom plate of each molding inner liner block 35, near the inner molding side wall 351. Four long strip-shaped overflow chip removal grooves 39 are evenly opened and arranged along the circumference of the mold cavity. The overflow chip removal groove 39 runs through the inside and outside of the bottom plate. During the pressing process, excess bone chips and bone marrow tissue in the molding cavity 37 can be discharged outward through the overflow chip removal groove 39 to avoid accumulation that causes the bone block to bulge and exceed the dimensional tolerance.

[0059] The delivery locator 2 is a long rod-shaped bone graft delivery device with an overall axial length of 195mm~205mm. It is divided into a second handle part 21 and a blunt end delivery head 22 along the axial direction, and the two are integrally machined.

[0060] The second handle 21 is cylindrical with a knurled, non-slip texture on its outer surface for stable grip and manipulation by the surgeon. The blunt-ended delivery head 22 is integrally connected to the distal end of the second handle 21, gradually narrowing from proximal to distal, ending in a spoon-shaped bearing end and a flattened overall shape. All exposed edges of the blunt-ended delivery head 22 are rounded with a radius of 0.5mm, eliminating any sharp structures and preventing scratches to soft tissues, tendons, and nerves when inserted into the surgical area. The lower and left / right sides of the blunt-ended delivery head 22 have smooth, rounded blunt edges, oriented towards the insertion point of the posterior tibial tendon and the medial dorsalis pedis cutaneous nerve during operation, structurally avoiding sharp contact injuries. The fixation structure 23 is located on the upper bearing surface of the blunt-ended delivery head 22, consisting of a wedge-shaped limiting groove and four sets of clamping arms 24, used to temporarily fix the shaped bone block and prevent displacement or dislodgement during delivery.

[0061] The wedge-shaped limiting groove is recessed in the center of the bearing surface. The outer dimensions of the groove are adapted to the molded bone block. The groove wall is smooth and is used to support the bottom and sides of the molded bone block, restricting the lateral displacement of the bone block.

[0062] Four clamping arms 24 are provided, symmetrically distributed in pairs on the left and right sides of the limiting groove. Each clamping arm 24 is a 0.2mm thick elastic stainless steel spring. One end of the spring is fixed to the side wall of the blunt-end delivery head 22 by laser welding, and the other end extends upwards into the limiting groove. In its natural state, the end of the spring converges towards the center of the groove, with the end 2mm above the bottom of the groove, pressing the formed bone block from above. The end of the spring is rounded with an R0.3mm radius to avoid scratching the surface of the bone block; the bone block can be easily removed and placed by prying the spring apart.

[0063] The delivery rod 4 is a straight rod-shaped pushing instrument with an overall axial length of 175mm~185mm, comprising a rod body 42 and a ball 41. The rod body 42 is a 2.5mm diameter stainless steel round rod with a polished surface; the proximal 50mm length of the rod body 42 is knurled for anti-slip treatment, facilitating the operator's grip and pushing. The ball 41 is integrally formed on the distal end face of the rod body 42, and is a smooth stainless steel ball with a 3mm diameter, polished to Ra0.4μm; the diameter of the ball 41 is slightly smaller than the width of the limiting groove, allowing it to slide smoothly along the inner cavity of the limiting groove. The spherical surface makes surface contact with the bone block, ensuring uniform stress distribution during pushing, preventing puncture or fragmentation of the formed bone block, and allowing for slight deviations in the pushing angle, thus improving operational tolerance.

[0064] This instrument kit is designed for accessory navicular bone resection combined with hindfoot fusion or medial column elevation surgery, and is performed entirely under aseptic conditions. The specific working process is as follows: S1. Preoperative Preparation Stage: Before surgery, place the sterilized posterior tibial tendon insertion separator 1, small bone block molding device 3, delivery locator 2, and delivery rod 4 on the sterile instrument table in the order of use. Connect the negative pressure tube interface 12 of the posterior tibial tendon insertion separator 1 to the negative pressure suction line of the operating room, adjust the negative pressure to 0.02~0.03MPa, and confirm that the suction port 19 is unobstructed. According to the preoperatively planned bone graft site, select the molding inner liner block 35 with the corresponding mold cavity shape, and insert it into the molding block 34 slot of the small bone block molding device 3, confirming that the inner liner block is firmly installed and accurately aligned.

[0065] S2. Soft Tissue Separation and Anatomical Protection Stage: The surgeon makes a standard arc-shaped incision along the medial side of the foot, cutting through the skin and subcutaneous tissue layer by layer. After exposing the superficial structures of the accessory navicular bone region, the surgeon holds the first handle 11 of the tibialis posterior tendon insertion separator 1 and slowly inserts the distal working head 13 into the surgical area along the soft tissue gap. The angle of the instrument is adjusted so that the distal insertion guard 15 is aligned with the lower edge of the tibialis posterior tendon insertion point, and is steadily lifted below the tendon insertion point, allowing the limiting ridge 16 to be locked at the lateral edge of the tendon insertion point, restricting the tendon within the protection range of the guard; at the same time, the two flexible wings 14 naturally open, pushing the medial dorsalis pedis cutaneous nerve branches to the sides, away from the operating area. Keeping the protective support stable, with the blunt blade assembly 17 on the front of the working head against the surface of the accessory navicular bone, the instrument is moved back and forth along the bone surface, bluntly dissecting the periosteum, fibrous tissue, and soft tissue adhesions on the surface of the accessory navicular bone layer by layer using three layers of stepped blunt edges. During the dissection, negative pressure is continuously maintained, and bleeding and small tissue debris generated during dissection are suctioned away in real time through the suction port 19, ensuring a clear view of the dissection interface at all times. After blunt dissection until the junction of the accessory navicular bone and the navicular bone is fully exposed, the separator is kept in place, temporarily shielding and protecting the insertion point of the posterior tibialis tendon and the cutaneous nerve, providing a safe operating space for subsequent osteotomy.

[0066] S3. Accessory Scaphoid Removal and Bone Segment Formation Stage: Under the protection of the tibialis posterior tendon insertion separator 1, the accessory scaphoid is completely removed using a bone scalpel or oscillating saw, while simultaneously smoothing the protruding osteophytes on the medial side of the scaphoid. The removed complete accessory scaphoid and the smoothed medial scaphoid fragments are collected using a sterile bone spatula and transferred to the small bone segment molding device 3 on a sterile table. The tibialis posterior tendon insertion separator 1 is removed, and the surgical area is rinsed with saline. After confirming there is no active bleeding, the surgical area is temporarily covered with gauze. The surgeon holds the operating arm of the small bone segment molding device 3 with one hand, keeping the clamp open. The collected accessory scaphoid and bone fragments are placed into the open molding cavity 37, and the position of the bone segment is adjusted so that the positioning pin 38 penetrates the bone segment to complete pre-fixation. The bone fragments fill the gaps around the bone segment. The surgeon inserts their fingers into the finger ring and slowly, evenly, pinches the two operating arms together. Through leverage, the shaping blocks 34 and the inner lining block 35 on both sides gradually align. During clamping, the elastic body 352 is gradually compressed, buffering the clamping force and ensuring the bone block and bone fragments are evenly compressed within the molding cavity 37. Pressure is applied until the clamping body is fully aligned, and the clamping state is maintained for 10-15 seconds, allowing the bone block to be compacted within the molding cavity 37 into a shape consistent with the cavity's shape. Excess bone fragments and bone marrow tissue are automatically discharged from the cavity through the overflow chip removal channel 39, ensuring the bone block has a regular shape and precise dimensions. The clamping body is slowly opened, and the shaped bone block is removed with sterile forceps. The bone block is checked for integrity, absence of fragmentation, and dimensions that meet the requirements for bone grafting.

[0067] S4. Bone Piece Delivery and Placement Stage: The surgeon holds the second handle 21 of the delivery locator 2 with one hand, and uses forceps to pry open the clamping arms 24 on both sides of the limiting groove with the other hand, smoothly placing the shaped bone piece into the wedge-shaped limiting groove; after releasing the clamping arms, the elastic clamping arms 24 spring back, pressing the bone piece from above, so that the bone piece is stably limited at the bearing end, without the risk of loosening or dislodgement. The surgeon holds the handle of the delivery locator 2 and slowly inserts the blunt end delivery head 22 into the medial surgical area of ​​the foot along the original surgical incision; during delivery, keep the blunt end facing the deep tissue, and use the smooth blunt edge of the delivery head to push away the surrounding soft tissue and the insertion point of the tibialis posterior tendon to avoid sharp contact injury. When the blunt end delivery head 22 reaches the preset hindfoot fusion surface or medial column elevation point, adjust the instrument angle so that the opening of the limiting groove is directly opposite the bone graft site, keeping the delivery locator 2 in a stable position.

[0068] S5. Bone Patch Placement and Instrument Removal Stage: The surgeon holds the delivery rod 4 with their other hand and inserts the distal ball 41 along the proximal opening of the limiting groove, ensuring the ball's surface aligns with the proximal end face of the formed bone patch. Maintaining the rod 42 coaxial with the limiting groove, the surgeon slowly pushes the delivery rod 4 forward. During this process, the clamping arm 24 automatically and elastically expands outward under the force of the bone patch, releasing its restraint. The ball 41 drives the formed bone patch to slide smoothly forward along the limiting groove until the bone patch is completely detached from the delivery head and precisely placed at the target bone graft site. After confirming that the position and angle of the formed bone patch meet the surgical requirements, the surgeon first retracts the delivery rod 4 until it is completely detached from the delivery locator 2, then slowly withdraws the delivery locator 2. During withdrawal, the delivery head is kept stable to avoid touching the displaced bone patch. Subsequent procedures include bone patch fixation and incision suturing, and the entire instrument set is disposed of according to medical protocols after use.

[0069] The above embodiments and verification examples are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An auxiliary instrument for shaping, modifying, and delivering accessory navicular bones during surgery, characterized in that, include: The posterior tibial tendon insertion separator (1) includes a first handle (11) and a distal working head (13) located at one end of the first handle (11). The distal working head (13) is boot-shaped. An insertion guard (15) is provided at the lower edge of the distal end of the distal working head (13). A blunt blade assembly (17) is provided on the side wall of the distal working head (13) above the insertion guard (15). Small bone block molding device (3), the small bone block molding device (3) includes a first clamp (31) and a second clamp (32), the middle of the first clamp (31) and the second clamp (32) are connected by a rotation fulcrum (33), one end of the first clamp (31) and the second clamp (32) are provided with a molding block (34), and molding inner liner blocks (35) can be detachably installed on the opposite sides of the two molding blocks (34). When the molding inner liner blocks (35) are joined, a molding cavity (37) is formed on the inner side. The molding cavity (37) is constructed to mold the accessory navicular bone into a hindfoot bone graft or a medial column for raising the bone block; Delivery locator (2), the delivery locator (2) includes a second handle part (21) and a blunt end delivery head (22) provided at the distal end of the second handle part (21), the blunt end delivery head (22) is provided with a fixation structure (23) for limiting the placement of the molded bone block. Delivery rod (4) is used to push the molded bone block on the fixation structure (23) out and push it to the hindfoot fusion surface or the medial column pad elevation site.

2. The auxiliary instrument for intraoperative shaping, modification, and delivery of the accessory navicular bone according to claim 1, characterized in that: The molded inner liner block (35) includes an outer shell (353) and an inner molded sidewall (351). The outer shell (353) includes a bottom plate and a side plate connected to the molded block (34). An elastomer (352) is provided between the side plate and the inner molded sidewall (351).

3. The auxiliary instrument for intraoperative shaping, modification, and delivery of the accessory navicular bone according to claim 2, characterized in that: A positioning pin (38) for insertion into the accessory navicular bone is mounted on the base plate of any of the molded inner liner blocks (35).

4. The auxiliary instrument for intraoperative shaping, modification, and delivery of the accessory navicular bone according to claim 3, characterized in that: The base plate is provided with a number of elongated overflow chip discharge grooves (39) near the inner forming side wall (351).

5. The auxiliary instrument for intraoperative shaping, modification, and delivery of the accessory navicular bone according to claim 1, characterized in that: The first handle part (11) of the posterior tibial tendon insertion separator (1) is provided with a negative pressure tube interface (12) at its proximal end. The distal working head (13) is provided with a suction port (19) on its side wall between the insertion guard (15) and the blunt blade assembly (17). The suction port (19) and the negative pressure tube interface (12) are connected through a channel (18) inside the first handle part (11) and the distal working head (13).

6. The auxiliary instrument for intraoperative shaping, modification, and delivery of the accessory navicular bone according to claim 5, characterized in that: The blunt edge group (17) includes three blunt edges whose height increases sequentially from the distal end to the proximal end. The three blunt edges form a stepped layered structure, and the cutting edges of the blunt edges are all blunt rounded corners.

7. The auxiliary instrument for intraoperative shaping, modification, and delivery of the accessory navicular bone according to claim 6, characterized in that: The upper edge of the stop guard (15) is provided with a raised limiting ridge (16), which extends along the arc of the stop guard (15).

8. The auxiliary instrument for intraoperative shaping, modification, and delivery of the accessory navicular bone according to claim 6, characterized in that: The distal working head (13) extends a flexible wing (14) on each of its left and right sides, and the flexible wing (14) is raised towards the instep side.

9. The auxiliary instrument for intraoperative shaping, modification, and delivery of the accessory navicular bone according to claim 1, characterized in that: The delivery rod (4) includes a rod body (42) and a ball (41) disposed at the end of the rod body (42).

10. The auxiliary instrument for intraoperative shaping, modification, and delivery of the accessory navicular bone according to claim 1, characterized in that: The retaining structure (23) includes a retaining groove for retaining the molding block and a plurality of clamping arms (24) located on both sides of the retaining groove. The clamping arms (24) are springs, one end of which is fixed to the blunt end delivery head (22), and the other end of which extends above the retaining groove.

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