Internal intramedullary fixation device

Abstract

This invention discloses an internal intramedullary fixation device, comprising an intramedullary support rod that can be installed within the medullary cavity. At least one rack parallel to the axial direction is provided on the main body of the intramedullary support rod. Radial screw holes are provided radially in the rack area, and radial locking screws are fitted into each radial screw hole. A shifting tool that engages with the rack is also provided. This invention combines the advantages of intramedullary nails and plates while avoiding their disadvantages. Fractures can be reduced under direct vision, achieving anatomical reduction while preserving soft tissue attachment and blood supply to the fracture fragments. The intramedullary support rod is implanted from the fracture end, making the operation simple and easy to learn. The implantation position of the intramedullary support rod can be flexibly adjusted according to the fracture type to facilitate the addition of screws for fracture fixation.

Description

Technical Field

[0001] The invention belongs to the technical field of fracture fixation instruments, and in particular relates to a built-in intramedullary fixation device. Background Art

[0002] The methods of internal fixation of fractures are nothing more than steel plates and intramedullary nails. Steel plate internal fixation is simple to operate and has a short learning cycle, but it is very traumatic and has a high chance of accidental injury. Infection, nonunion, delayed union, broken nails and broken plates often occur. The postoperative scar is large, which affects the appearance and does not conform to the principle of minimally invasive surgery. Intramedullary nails use closed and minimally invasive technology. Locking intramedullary nails can prevent fracture rotation deformity and reduce the risk of internal fracture; reduce surgical infection rate; promote a high fracture healing rate; central fixation avoids stress shielding and has a low incidence of re-fracture; conform to the principle of minimally invasive surgery and is the current development direction, but it is difficult to operate and learn, and it is difficult to lock the distal end of the intramedullary nail. Reduction is divided into closed and limited incision, but both are non-anatomical reduction, nonunion and delayed union may occur, and the patient is under great pressure. Summary of the invention

[0003] Aiming at various drawbacks of current fracture fixation methods, the present invention develops a built-in intramedullary fixation device suitable for fractures of long and short tubular bones of limbs, which has the characteristics of simple operation, small trauma and small postoperative scar.

[0004] Technical solution: A built-in intramedullary fixation device, including an intramedullary support rod that can be installed in the medullary cavity, at least one rack parallel to the axial direction is provided on the main body of the intramedullary support rod for left and right adjustment, and is equipped with a shifting tool that can be engaged with the rack, radial screw holes are radially arranged in the rack area, and radial locking nails are matched and installed in each radial screw hole.

[0005] A built-in intramedullary fixation device comprises an intramedullary absorbable material support rod which can be installed in the medullary cavity. A series of radial screw holes are radially arranged on the body of the intramedullary absorbable material support rod, and a radial locking nail is matched and installed in each radial screw hole.

[0006] In order to facilitate the installation of radial locking nails, a positioning mounting frame is also provided. A positioning mounting frame for the built-in intramedullary fixation device, the positioning mounting frame is parallel to the intramedullary support rod, and positioning holes are distributed on the positioning mounting frame, each positioning hole corresponds to the position of each radial screw hole, an initial positioning pin is fixedly installed in one of the positioning holes, a side key is provided on the side of the initial positioning pin, and a keyway is provided on the inner wall of at least one radial screw hole of the intramedullary support rod, the initial positioning pin can be matched and inserted into the radial screw hole, and the side key and the keyway can be matched and installed.

[0007] In the above solutions, the intramedullary support rods can be replaced with variable prisms, or circular or semicircular shapes.

[0008] In addition, auxiliary screw holes can be further provided on the intramedullary support rod, the centers of the auxiliary screw holes and the radial screw holes are no longer on the same generatrix, and the positioning mounting frame is also provided with auxiliary positioning holes matching the positions of the auxiliary screw holes, so as to facilitate the use in coping with comminuted fractures.

[0009] The present invention has the advantages of intramedullary nails (minimally invasive and central fixation) and steel plates (anatomical reduction and firm fixation) and avoids the disadvantages of intramedullary nails (difficult distal locking) and steel plates (large incision, large trauma, and wide periosteal stripping). This is because it has the following characteristics.

[0010] 1. Prismatic design, especially triangular design, has the most stable contact between the medullary cavity ridges, minimal damage to the medullary cavity wall, and minimal disruption to microcirculation. The intramedullary support rod is fixed to the backbone by screws, and has the characteristics of firm and stable fixation.

[0011] 2. Reducing the fracture under direct vision can achieve anatomical reduction, preserve the soft tissue attachment of the fracture fragments, preserve blood supply, and implant the intramedullary support rod from the fracture end. The operation is simple and easy to learn.

[0012] 3. The implantation position of the intramedullary support rod can be flexibly adjusted according to the fracture type. For example, for comminuted fractures, the intramedullary support rod is rotated to keep the radial screw hole corresponding to the area with more bone fragments, so as to facilitate the use of screws to fix the fracture.

[0013] 4. Select an intramedullary support rod of appropriate length according to the length of the fracture and the bone shaft. Fix the center and apply pressure to the center to minimize the fracture gap. Fix butterfly-shaped and other fragments stably. For example, for comminuted fractures, use the intramedullary support rod to pull the two sides of the broken bone and apply pressure inward, so that the broken bones can be clamped in the bone gap and kept naturally clamped.

[0014] 5. The incision only needs to expose the fracture ends to achieve reduction, thus achieving the purpose of minimally invasive surgery.

[0015] 6. No need for medullary expansion or very short medullary expansion, which reduces the occurrence of fat embolism and the amount of internal bleeding.

[0016] 7. The intramedullary support rod is locked with direct vision locking technology, without or with little fluoroscopy. Mechanical navigation locking can be used for locking away from the wound. Since the intramedullary support rod is short, the force arm is very short, so the deformation probability of the intramedullary support rod is very low, and it is easy to lock the radial screw hole (the existing intramedullary nail needs to be driven in from the end of the bone, with a large span and a large deformation at the end, making it difficult to lock the locking hole at the end). BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a front structural schematic diagram of the intramedullary support rod of the present invention.

[0018] Figure 2 yes Figure 1 Schematic diagram of the AA cross-section structure.

[0019] Figure 3 It is a schematic diagram of positioning and installation of the present invention.

[0020] Figure 4 yes Figure 3 Middle initial positioning pin anti-slip key assembly structure.

[0021] Figure 5 yes Figure 1 One of the schematic diagrams of the BB section structure.

[0022] Figure 6 yes Figure 1 The second schematic diagram of the BB cross-section structure.

[0023] Figure 7 yes Figure 1 The third schematic diagram of the BB cross-section structure.

[0024] Figure 8 yes Figure 1 The fourth schematic diagram of the BB cross-section structure.

[0025] Fig. 9 It is a schematic diagram of the initial state of installation of the intramedullary support rod of the present invention.

[0026] Fig.10 It is a schematic diagram of the intramedullary support rod of the present invention being installed on the left part of a broken bone.

[0027] Fig.11 It is a schematic diagram of using a shifting tool to drive the translation of the intramedullary support rod.

[0028] Fig.12 It is a schematic diagram of the structure in which the intramedullary support rod is simultaneously built into both sides of the broken bone.

[0029] Fig.13 This is a schematic diagram of fixing the built-in intramedullary support rod by radial locking nails.

[0030] Fig.14 This is a schematic diagram of the removal of the intramedullary support rod from the side after rehabilitation.

[0031] Fig.15 Schematic diagram of installing an intramedullary support rod for a comminuted fracture.

[0032] Fig.16 Schematic diagram of removing the intramedullary support rod from the end axial hole.

[0033] Fig.17 It is a schematic diagram of the special locking pin with inner card table.

[0034] Fig.18 It is a front structural schematic diagram of another intramedullary support rod of the present invention.

[0035] Numbers in the figure: 1 is the intramedullary support rod, 2 is the radial screw hole, 3 is the rack, 4 is the positioning mounting frame, 5 is the initial positioning pin, 6 is the side key, 7 is the keyway, 8 is the positioning hole, 9 is the radial locking nail, 10 is the drill, 11 is the thread, 12 is the initial shifting hole, 13 is the shifting tool, 14-1 is the left part of the broken bone, 14-2 is the right part of the broken bone, 15 is the medullary cavity, 16 is the bone side hole fragment, 17 is the bone side opening, and 18 is the end axial hole. DETAILED DESCRIPTION

[0036] Example 1: Figure 1 The internal intramedullary fixation device shown is suitable for fixing long and short tubular bone fractures of the limbs, wherein the intramedullary support rod 1 can be installed in the medullary cavity 15 and can slide freely. The internal support rod is a smooth equal-diameter rod with smooth or tapered ends to facilitate assembly. Figure 6 As shown, this embodiment preferably uses an intramedullary support rod 1 with a triangular cross-section.

[0037] A rack 3 is provided in the middle of at least one of the three sides of the main body of the intramedullary support rod 1, and the rack 3 is parallel to the axial direction. Figure 2 As shown, radial screw holes 2 are evenly distributed in the rack 3 region at radially equal intervals d, and the centers of the radial screw holes 2 are located on the same generatrix.

[0038] When this implementation is used, see Fig. 9 , insert the intramedullary support rod 1 from the fractured bone into the left part 14-1 of the fractured bone. Fig.10 At the same time, a hole needs to be opened on the side of the left part 14-1 of the broken bone corresponding to the rack 3 as the initial shift hole 12. Since the initial shift hole 12 is directly opposite to the rack 3 on the intramedullary support rod 1, the intramedullary support rod 1 can be shifted left and right after the shift tool 13 passes through the initial shift hole 12. The tip position of the shift tool 13 can be engaged with the rack 3.

[0039] like Fig.12 As shown, the intramedullary support rod 1 is moved approximately equally to the inner cavity on both sides of the broken bone by shifting the tool 13. At this time, all or part of the intramedullary screw holes on the intramedullary support rod 1 need to be fixed by radial locking nails 9. After installing the radial locking nails 9, the intramedullary support rod 1 can be firmly positioned between the two broken bones to achieve the purpose of fixation.

[0040] like Fig.13As shown, in the process of installing each radial locking nail 9 into the corresponding radial screw hole 2, it is necessary to drill holes in the left part 14-1 of the broken bone and the right part 14-2 of the broken bone respectively. At this time, there are two ways. One is to use the center of the initial shift hole 12 as the starting point, and determine the drilling position by a ruler or experience; the other way is to quickly determine the drilling position by positioning the mounting frame 4. There are two ways to drill holes. One is to use a drill to install a radial locking nail 9 with a self-tapping thread, and the diameter passes through the side wall of the broken bone and enters the radial screw hole 2 of the intramedullary support rod 1; the other way is to first drill holes at the corresponding positions with a drill, and then install the radial locking nail 9 after drilling.

[0041] Through the above structural relationship, the intramedullary support rod 1 can flexibly adjust the implantation position according to the fracture type to facilitate the addition of screws to fix the fracture. According to the fracture and the length of the bone shaft, the appropriate length of the intramedullary support rod 1 is selected. The outstanding features of the above structure of this embodiment are: (1) It has the function of pulling toward the center. After fixing one side, by turning the rack again, the left part 14-1 of the broken bone and the right part 14-2 of the broken bone can be tightened and pressed toward the center. This method can not only keep the left part 14-1 of the broken bone and the right part 14-2 of the broken bone firmly connected, but also provide compression protection for comminuted fractures (because the tubular bone contains an inner cavity, the intramedullary support rod supports from the inside, which can prevent bone fragments from entering the inner cavity, thereby making it feasible to squeeze the broken bone inward). (2) Central traction This local traction and docking relationship can ensure that the periphery of the broken bone is uniformly stressed and shrinks toward the center (in the implementation of the existing fixation scheme, it is inevitable that the peripheral stress shielding will occur when the broken bones are connected, resulting in unevenness). (3) Central fixation can apply pressure to minimize the fracture gap, which is conducive to the stability of butterfly fracture fragments. This can shorten the operation time from several hours to about half an hour, reduce the risk of surgery, and have little impact on the soft tissue of the patient's fracture fragment during the operation, which is conducive to recovery.

[0042] The material of the built-in intramedullary support rod 1 of the present invention can be a metal material that needs to be removed later, or an absorbable material. When a metal material is used, after recovery, the rod can be removed by Fig.14 The removal method is to remove the built-in intramedullary support rod 1 by opening a hole in the bone side wall in the area of ​​the built-in intramedullary support rod 1. The hole opening method can be a full-open method or a half-open method. Half-open means that after a hole is opened on one side of the intramedullary support rod 1, the built-in intramedullary nail is pulled outward along an inclined direction. When an absorbent material is used, no subsequent removal operation is required.

[0043] The present invention can select different models (with different lengths and diameters) of intramedullary support rods 1 for use according to the location of the fracture site. Fig.15 When the fracture is located near the fixed end, or when a longer intramedullary support rod 1 is implanted due to a comminuted fracture, the following method can be used after recovery: Fig.16The removal method shown is to open the end axial hole 18 at the fixed end and remove the intramedullary support rod 1 from the end.

[0044] It is best to design one end of the intramedullary support rod 1 to be sharp, so as to facilitate the removal from one end later. The radial locking nail 9 is preferably designed as a full-thread self-tapping nail. Alternatively, a matching driving and ejecting device and a mechanical navigation device can be designed separately.

[0045] Compared with the existing minimally invasive and centrally fixed intramedullary nails, the present invention can reduce the fracture under direct vision, achieve anatomical reduction, and avoid the problem of difficult locking of the distal end of the intramedullary nail. The intramedullary support rod 1 is implanted from the fracture end, and the operation is simple and easy to learn. Since the locking of the intramedullary support rod 1 adopts direct vision locking technology, no fluoroscopy or very little fluoroscopy is required, and the locking away from the wound can be locked by mechanical navigation. Since the lever arm is very short, the deformation probability of the intramedullary support rod 1 is very low, and the probability of difficulty in locking is very low. In addition, there is no need for medullary expansion or very short medullary expansion, which reduces the occurrence of fat embolism and the amount of internal bleeding.

[0046] Compared with steel plate fixation (large incision, large trauma, and wide periosteum stripping), the incision of the present invention only needs to expose the fracture end to achieve reduction, thereby achieving the purpose of minimally invasive surgery and being able to preserve the soft tissue attachment of the fracture fragment and the blood supply.

[0047] Example 2: Based on Example 1, Figure 3 and Figure 4 The positioning mounting frame 4 shown has a main rod member parallel to the intramedullary support rod 1. Positioning holes 8 are distributed at equal intervals d on the main rod member of the positioning mounting frame 4, and the positions of the radial screw holes 2 on the internal intramedullary support rod 1 are determined by using the positioning holes 8 of the external positioning mounting frame 4.

[0048] like Figure 3 As shown, an initial positioning pin 5 is fixedly installed in one of the positioning holes 8, and a side key 6 is provided on the side of the initial positioning pin 5. At the same time, a keyway 7 is provided on the inner wall of at least one radial screw hole 2 of the intramedullary support rod 1, and the initial positioning pin 5 can be inserted into the radial screw hole 2, and the side key 6 and the keyway 7 can be installed in a matching manner. The matching relationship between the side key 6 and the keyway 7 can prevent the positioning mounting frame 4 from rotating, so that the direction of each positioning hole 8 can be ensured to be consistent with the direction of each radial screw hole 2. When the broken bone is drilled with each positioning hole 8 as the center, it can directly correspond to the radial screw hole 2 on the inside.

[0049] Embodiment 3: Based on Embodiment 1 or 2, the intramedullary support rod 1 is a variable prism type, see Figure 5 The regular hexagonal prism shown, Figure 7 The square prism and Figure 8The circular or semicircular prism shown. The prism design can especially adopt a triangular design, the ridgeline contact of the medullary cavity 15 is the most stable, the damage to the wall of the medullary cavity 15 is minimal, and the microcirculation is minimally damaged. The intramedullary support rod 1 is fixed to the backbone by screws, and has the characteristics of firm and stable fixation.

[0050] Embodiment 4: Based on Embodiment 1 or 2, auxiliary screw holes are respectively provided on the intramedullary support rod 1, and the centers of the auxiliary screw holes and the radial screw holes 2 are no longer on the same generatrix. This design can be used for partial comminuted fractures and can fix the broken bones by multi-directional fixation.

[0051] Example 5: Based on Example 1 or 2, if after installing the radial locking nail, it is found that the left part 14-1 of the broken bone and the right part 14-2 of the broken bone are not tightly connected, or it is necessary to forcibly squeeze the left part 14-1 of the broken bone and the right part 14-2 of the broken bone, the initial displacement hole can be expanded outward, and then the radial locking nail can be installed in the initial displacement hole. Fig.17 Alternatively, if the initial shift hole on the fractured bone is too large to be used, the initial shift hole is directly abandoned.

[0052] Embodiment 6: Another internal intramedullary fixation device, such as Fig.18 As shown, the fixing device is an intramedullary absorbable material support rod that can be installed in the medullary cavity. A series of radial screw holes are radially arranged on the main body of the intramedullary absorbable material support rod, and radial locking nails are matched and installed in each radial screw hole. Its function and installation method are as described in Example 1 and are not described in detail. The intramedullary absorbable material support rod used in this embodiment can complete the treatment or necessary review after the first operation, without the need for removal surgery.

Claims

1. A built-in intramedullary fixation device, characterized in that: The invention comprises an intramedullary support rod which can be installed in the intramedullary cavity, wherein at least one rack parallel to the axial direction is arranged on the main body of the intramedullary support rod for left and right adjustment, radial screw holes are arranged radially in the rack area, and radial locking nails are matched and installed in each radial screw hole; a positioning mounting frame is parallel to the intramedullary support rod, and positioning holes are distributed on the positioning mounting frame, and each positioning hole corresponds to the position of each radial screw hole, and the position of each radial screw hole (2) on the internal intramedullary support rod (1) is determined by using each positioning hole (8) of the external positioning mounting frame (4); after the shifting tool (13) passes through the initial shifting hole (12), the intramedullary support rod (1) can be shifted to the left and right, and the tip position of the shifting tool (13) can be engaged with the rack (3); an initial positioning pin is fixedly installed in one of the positioning holes, and a side key is arranged on the side of the initial positioning pin. At the same time, a key slot is arranged on the inner wall of at least one radial screw hole of the intramedullary support rod, and the initial positioning pin can be matched and inserted into the radial screw hole, and the side key and the key slot can be matched and installed; By utilizing the matching relationship between the side key (6) and the keyway (7), the positioning mounting frame (4) can be prevented from rotating, thereby ensuring that the direction of each positioning hole (8) is consistent with the direction of each radial screw hole (2); the drilling position is quickly determined by the positioning mounting frame (4), and there are two ways of drilling holes. One is to use a drill to install a radial locking nail (9) with a self-tapping screw, which directly penetrates the side wall of the broken bone and enters the radial screw hole (2) of the intramedullary support rod (1); the other is to first drill holes at corresponding positions with a drill, and then install the holes after drilling. Install radial locking nails (9); when the broken bone is drilled with each positioning hole (8) as the center, it can directly correspond to the radial screw hole (2) on the inside; after fixing one side with the initial positioning pin of the fixing frame, the rack is moved again to tighten the left and right parts of the broken bone and press them toward the center, which can not only keep the left and right parts of the broken bone firmly connected, but also provide compression protection for comminuted fractures; ensure that the periphery of the broken bone is evenly stressed and shrinks toward the center; the intramedullary support rod (1) is fixed to the bone shaft via screws.

2. The internal intramedullary fixation device according to claim 1, characterized in that: The intramedullary support rod is a support rod made of an intramedullary absorbable material.

3. The internal intramedullary fixation device according to claim 1, characterized in that: The intramedullary support rod is in a variable prism shape, or is circular or semicircular.

4. The internal intramedullary fixation device according to claim 1 is characterized in that: The intramedullary support rods are respectively provided with auxiliary screw holes, the centers of the auxiliary screw holes and the radial screw holes are no longer on the same generatrix, and the positioning mounting frame is also provided with auxiliary positioning holes matching the positions of the auxiliary screw holes.

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