Controllable self-expanding intramedullary nail internal fixation system and method for long bone fracture

Abstract

The application provides a controllable self-expanding intramedullary nail internal fixation system for long bone fracture, belonging to the technical field of orthopedic medical instruments, and comprising a self-expanding intramedullary nail, a visible controllable self-expanding platform and a locking nail; the self-expanding intramedullary nail comprises a locking hole and an expandable support; the locking hole is arranged at the proximal end of the self-expanding intramedullary nail and is matched with the locking nail to fix the proximal end of the self-expanding intramedullary nail; the expandable support is arranged at the distal end of the self-expanding intramedullary nail after expansion to fix the distal end of the self-expanding intramedullary nail. The visible controllable self-expanding platform is in communication with the expandable support and can display the expansion size, and the self-expanding intramedullary nail can be prevented from being expanded too large to affect the medullary cavity by precalculating the expansion size.

Description

Technical Field

[0001] This invention relates to the field of orthopedic medical device technology, specifically to a controllable self-expanding intramedullary nail internal fixation system and method for long bone fractures. Background Technology

[0002] With the development of modern transportation, traffic accidents are increasing. Humeral fractures are a common type of fracture in clinical practice, and internal fixation always plays a crucial role in their treatment. Intramedullary nailing is an internal fixation technique that uses an intramedullary nail along with oblique or transverse locking screws to form a unified structure with the entire long bone. This allows for better control of rotation and shear forces at the fracture ends, preventing rotational displacement at the fracture site. This expands the indications for intramedullary nailing to comminuted, long oblique, and femoral fractures, increasing the stability of fracture fixation, improving fracture healing rates, and reducing infection rates, thus providing a more biologically sound approach to fracture treatment.

[0003] However, the following shortcomings have been found in the routine clinical treatment of long bone fractures of the humerus:

[0004] 1. Locking intramedullary nails require additional surgical incisions due to their locking positions at both ends of the long bone shaft. The installation of the distal locking nail is a complicated procedure with significant side effects and damage.

[0005] 2. In the reduction surgery of long bone fractures, because the intramedullary nails required for long bone fractures are relatively long, an external intramedullary nail positioning frame is conventionally used to position the distal locking nail. However, the long intramedullary nail will deform due to stress changes inside the medullary cavity, which will change the distance between it and the main positioning rod. This makes it impossible for the external positioning frame to be accurately positioned, resulting in the distal locking hole of the intramedullary nail and the positioning hole on the main positioning rod no longer being on the same plane. This often leads to drilling failure, requiring drilling again under CT or X-ray, which not only prolongs the operation time and increases the difficulty of the operation, but also affects the surgical outcome and increases the patient's pain.

[0006] 3. Intramedullary nailing is a common treatment method in orthopedics for long bone fractures. However, the diameter of the medullary cavity limits the use of intramedullary nails. Using an intramedullary nail of an inappropriate diameter can irritate and compress the medullary cavity, affecting the blood supply to the endosteal membrane and thus affecting intramedullary healing.

[0007] Existing technologies employ a distal self-expanding fixation and proximal locking fixation structure to address the aforementioned problems. However, in practical use, the size of the self-expansion cannot be precisely controlled. When the self-expansion structure expands too much, it can compress the medullary cavity, affecting or even damaging the endosteal membrane. When the self-expansion structure expands too little, the fixation strength is insufficient, and the intramedullary nail may shift, affecting the rehabilitation outcome. Furthermore, the existing self-expansion mechanisms are complex and inconvenient to operate, and therefore require improvement.

[0008] Therefore, the present invention provides a controllable self-expanding intramedullary nail internal fixation system for long bone fractures and a method of using it. Summary of the Invention

[0009] The purpose of this invention is to provide a controllable self-expanding intramedullary nail internal fixation system for long bone fractures.

[0010] To solve the above-mentioned technical problems, the objective of this invention is achieved as follows:

[0011] A controllable self-expanding intramedullary nail internal fixation system for long bone fractures includes: a self-expanding intramedullary nail, a visually controllable self-expanding platform, and locking screws;

[0012] The self-expanding intramedullary nail includes a locking hole and an expandable scaffold; the locking hole is located at the proximal end of the self-expanding intramedullary nail and is adapted to the locking screw to fix the proximal end of the self-expanding intramedullary nail; the expandable scaffold is located at the distal end of the self-expanding intramedullary nail, dividing the self-expanding intramedullary nail into a proximal segment and a distal segment;

[0013] The self-expanding intramedullary nail has a hollow interior forming an operating cavity; the operating cavity has a distal internal thread in the distal segment and a proximal internal thread in the proximal segment.

[0014] The visible and controllable self-expanding platform includes a drive worm, a worm wheel, and a housing. The drive worm is meshed with the worm wheel inside the housing, and both ends of the drive worm extend outside the housing. One end can extend into the operating cavity and connect to the drive screw. The drive screw is threadedly connected to the distal internal thread and the proximal internal thread, and the other end is used to control rotation. A worm wheel shaft is fixedly installed at the center of the worm wheel, and a pointer is fixedly installed at the other end of the worm wheel shaft. The pointer is correspondingly equipped with a scale.

[0015] Based on the above scheme and as a preferred embodiment of the above scheme, the expandable stent includes several expandable connecting plates, each expandable connecting plate including two connecting plates, which are flexibly connected to each other, and the ends of the two connecting plates are flexibly connected to the self-expanding intramedullary nail.

[0016] Based on the above scheme and as a preferred embodiment of the above scheme, the locking hole includes several horizontal locking holes and upward oblique locking holes; the opening directions of the several horizontal locking holes are different.

[0017] Based on the above scheme and as a preferred embodiment of the above scheme, the locking pin is a self-expanding locking pin, including a locking pin body and an opening bracket; the opening bracket is disposed at the end of the locking pin body and is driven to expand by a screw core disposed inside the locking pin body; the opening bracket is provided with a drug release hole.

[0018] Based on the above scheme and as a preferred embodiment, the method further includes an intramedullary nail implantation mechanism; the intramedullary nail implantation mechanism includes an insertion handle, a proximal aiming bracket, and a locking sleeve; one end of the insertion handle can be connected to a proximal connection hole opened at the top of the proximal end of the self-expanding intramedullary nail, and the other end is connected to the proximal aiming bracket through an aiming bracket bolt; the locking sleeve cooperates with the proximal aiming bracket to screw the locking nail into the locking hole.

[0019] Based on the above solution and as a preferred embodiment, a limit rod is provided on the housing; the limit rod can lock the worm gear.

[0020] The present invention also provides a method of using the controllable self-expanding intramedullary nail internal fixation system for long bone fractures as described in any of the above claims, comprising the following steps:

[0021] Step 1: Preoperative preparation: Determine the width h of the patient's medullary canal under CT or X-ray. Select a suitable self-expanding intramedullary nail based on the width h. Calculate the insertion depth Δ of the drive screw using the medullary canal width h and the single-arm length R of the expandable scaffold of the intramedullary nail. The calculation formula is as follows:

[0022] (R-△+x) 2 +h1 2 =R 2

[0023] (Rx) 2 +h1 2 =R 2

[0024] In the formula, x represents the distance the center point of the expandable stent moves relative to its original position; h1 is half of h;

[0025] After calculating △, the expansion size of the expandable support can be precisely controlled according to the dial.

[0026] Step 2: Insert the self-expanding intramedullary nail, which is in its natural state, into the long medullary cavity;

[0027] Step 3: Implant the visual and controllable self-expanding platform into the expandable intramedullary nail: Specifically, after connecting the drive screw and the drive worm gear, insert it into the operating cavity; rotate the drive worm gear to connect the drive screw to the distal internal thread, and continue to rotate the drive worm gear to expand the expandable support until the pointer turns to the predetermined position; then remove the visual and controllable self-expanding platform.

[0028] Step 4: Insert the locking pin into the locking hole at the tip of the intramedullary nail.

[0029] The beneficial effects of this invention are:

[0030] Compared with existing technologies, this invention breaks through traditional thinking. It not only eliminates the need for the expansion and compression method of the distal locking nail using a self-expanding intramedullary nail, but also allows for precise control of the expansion and compression distance using a visual and controllable self-expanding platform for patients with different medullary cavity sizes, effectively reducing the irritation and damage to the inner wall caused by excessive expansion inside the medullary cavity.

[0031] At the same time, it overcomes the disadvantages of positioning devices, such as cumbersome operation, multiple surgical incisions, complex supporting instruments, and static fixation. It has the advantages of simple surgical operation, relatively small damage, no need for special equipment, low manufacturing cost, and suitability for widespread application. It can achieve "tailor-made" precise, controllable and visual expansion of different patients' medullary cavities. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the self-expanding intramedullary nail of the present invention in its natural state;

[0033] Figure 2 This is a schematic diagram of the self-expanding intramedullary nail in its expanded state according to the present invention;

[0034] Figure 3 This is a schematic diagram of the self-expanding locking pin in its natural state according to the present invention;

[0035] Figure 4 This is a schematic diagram of the self-expanding locking pin in its expanded state according to the present invention;

[0036] Figure 5 This is a cross-sectional schematic diagram of the self-expanding locking expansion state of the present invention;

[0037] Figure 6 This is a structural diagram of the present invention, showing the use of an instrument to implant a self-expanding intramedullary nail into a long medullary cavity;

[0038] Figure 7 This is a front view of the visible and controllable self-expanding platform structure of the present invention;

[0039] Figure 8 This is a cross-sectional view of the visible and controllable self-expanding platform structure of the present invention;

[0040] Figure 9 This is a partially enlarged view of the self-expansion process structure of the present invention;

[0041] Figure 10 This is a schematic diagram of the self-expansion implementation scheme of the present invention;

[0042] Figure 11 This is a schematic diagram of the structure after implantation of the self-expanding locking pin according to the present invention;

[0043] Figure 12 This is a front view of the self-expanding intramedullary nail of the present invention in the state of completed expansion inside the medullary cavity;

[0044] In the diagram: 1. Self-expanding intramedullary nail; 11. Locking hole; 111. Horizontal locking hole; 112. Upward oblique locking hole; 12. Expandable support; 121. Expandable connecting plate; 122. Connecting plate; 13. Distal internal thread; 14. Proximal connecting hole; 15. Proximal internal thread; 2. Visual and controllable self-expanding platform; 21. Drive worm gear; 22. Worm gear; 23. Housing; 24. Worm gear shaft; 25. Pointer; 26. Dial; 27. Limiting rod; 28. Bearing; 29. ​​Key; 3. Locking nail; 31. Locking nail body; 32. Opening support; 33. Screw inner core; 34. Drug release hole; 4. Drive screw; 5. Insertion handle; 6. Proximal aiming support; 7. Locking nail sleeve; 8. Aiming frame bolt; 100. Medullary cavity. Detailed Implementation

[0045] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0046] A controllable self-expanding intramedullary nail internal fixation system for long bone fractures includes: a self-expanding intramedullary nail 1, a visually controllable self-expanding platform 2, a locking screw 3, and an intramedullary nail implantation mechanism.

[0047] like Figure 1 , Figure 2 and Figure 12 As shown, the self-expanding intramedullary nail 1 includes a locking hole 11 and an expandable scaffold 12; the locking hole 11 is located at the proximal end of the self-expanding intramedullary nail 1 and is adapted to the locking nail 3 to fix the proximal end of the self-expanding intramedullary nail 1; the expandable scaffold 12 is located at the distal end of the self-expanding intramedullary nail 1 and is used to fix the distal end of the self-expanding intramedullary nail 1 after self-expansion.

[0048] Preferably, the locking hole 11 includes several horizontal locking holes 111 and an upward oblique locking hole 112; the several horizontal locking holes 111 are opened in different directions, so that the locking nail 3 can be inserted from different directions, thereby improving the fixation effect. The upward oblique locking hole 112 fixes the self-expanding intramedullary nail 1 in an inclined state, which can also improve the fixation effect of the locking nail 3.

[0049] Specifically, such as Figures 3 to 5As shown, the locking pin 3 is preferably a self-expanding locking pin, including a locking pin body 31 and an opening bracket 32. The opening bracket 32 ​​is disposed at the end of the locking pin body 31 and is driven to expand by a screw core 33 disposed inside the locking pin body 31; the opening bracket 32 ​​is provided with a drug release hole 34. A receiving groove is opened at the front end of the locking pin body 31, and the opening bracket 32 ​​is slidably disposed in the receiving groove, with one end abutting against the screw core 33. Rotating the screw core 33 can push the opening bracket 32 ​​to move. Due to the inclination of the front part of the opening bracket 32, the opening bracket 32 ​​will expand as it moves forward, exposing the drug release hole 34 to release drugs. The self-expanding locking pin can not only improve the fixation effect, but the drug release hole 34 can also release some drugs such as those that promote bone growth to improve the intra-articular environment, which can significantly improve the bone environment inside the humeral head and accelerate healing.

[0050] like Figure 9 As shown, the expandable scaffold 12 divides the self-expanding intramedullary nail 1 into a proximal segment and a distal segment. It includes several expandable connecting plates 121 evenly distributed circumferentially along the self-expanding intramedullary nail 1. Each expandable connecting plate 121 includes two connecting plates 122, which are bendably connected. The ends of the two connecting plates 122 are bendably connected to the proximal and distal segments of the self-expanding intramedullary nail 1. When the expandable scaffold 12 expands, the two connecting plates 122 bend between each other and between the connecting plates 122 and the proximal and distal segments, causing the connecting plates 122 to expand outwards. Preferably, the two connecting plates 122 are integrally formed with the proximal and distal segments of the self-expanding intramedullary nail 1, with some structure removed at the bending connection points to allow for relative bending.

[0051] The self-expanding intramedullary nail 1 has a hollow interior forming an operating cavity; the operating cavity has a distal internal thread 13 in the distal segment and a proximal internal thread 15 in the proximal segment. The operating cavity extends from the proximal end of the self-expanding intramedullary nail 1 to the distal segment, but does not penetrate the distal segment.

[0052] Furthermore, the visually controllable self-expanding platform 2 includes a rotation mechanism and a display mechanism;

[0053] like Figure 7 and Figure 8As shown, the rotating mechanism includes a drive worm 21, a housing 23, and a drive screw 4. The drive worm 21 is located inside the housing 23, with both ends extending outside the housing 23. One end can extend into the operating cavity and connect to the drive screw 4. The preferred connection method is a pin connection, where the end of the drive screw 4 has a polygonal slot, and the end of the drive worm 21 has a corresponding polygonal pin. The torque transmitted through the engagement of the pin and the slot causes the drive worm 21 to drive the drive screw 4 to rotate. The surfaces of both ends of the drive screw 4 are provided with external threads, which are opposite in direction and are threadedly engaged with the distal internal thread 13 and the proximal internal thread 15. Due to the opposite threads, when the drive screw 4 rotates, the proximal and distal sections move closer or further apart, realizing the expansion and contraction of the expandable support 12.

[0054] The other end of the drive worm 21 is used to control rotation. In use, the operator can manually rotate this end to rotate the drive worm 21. The drive worm 21 extends into the operating cavity from the opening of the operating cavity at the proximal end of the self-expanding intramedullary nail 1. The drive worm 21 is rotatably connected to the housing 23 via a bearing 28, which drives the drive screw 4 to engage with the distal internal thread 13 and the proximal internal thread 15, causing the distal segment to move closer to the proximal segment, thus gradually expanding the expandable support 12.

[0055] The display mechanism includes a worm gear 22, a pointer 25, and a dial 26. The worm gear 22 is disposed inside the housing 23 and meshes with a drive worm 21. A worm gear shaft 24 is fixedly disposed at the center of the worm gear 22, and a pointer 25 is fixedly disposed at the other end of the worm gear shaft 24. The dial 26 is correspondingly disposed on the pointer 25. Preferably, the housing 23 is provided with a transparent panel, and the pointer 25 and the dial 26 are placed under the transparent panel. The worm gear 22 is fixedly connected to the worm gear shaft 24 by a key 29.

[0056] Preferably, a limit rod 27 is provided on the housing 23; the limit rod 27 can lock the worm gear 22. Specifically, the limit rod 27 is rotatably connected to the housing 23 and can be screwed into the housing 23 to lock the worm gear 22 to prevent the pointer 25 from rotating.

[0057] More preferably, the dial 25 has a value from 1 to 80, with each interval representing 0.1 mm. The large transmission ratio between the drive worm gear 21 and the worm wheel 22 amplifies minute displacements. Specifically, the transmission ratio between the drive worm gear 21 and the worm wheel 22 is 1:20. The distal expandable support 12 of the intramedullary nail is opened by the drive screw 4. After opening, rotating the limiting rod 27 locks the entire visible and controllable self-expanding platform. At this point, the value read from the dial is used as the depth to which the drive screw is screwed in.

[0058] like Figure 5 and Figure 11As shown, the intramedullary nail implantation mechanism includes an insertion handle 5, a proximal aiming bracket 6, and a locking sleeve 7. One end of the insertion handle 5 can be connected to the proximal connection hole 14 opened at the top of the proximal end of the self-expanding intramedullary nail 1, and the other end is connected to the proximal aiming bracket 6 through the aiming bracket bolt 8; the locking sleeve 7 cooperates with the proximal aiming bracket 6 to screw the locking nail 3 into the locking hole 11. The proximal connection hole 14 is opened at the opening of the operating cavity at the proximal end, and is adapted to the insertion handle 5. Preferably, the insertion handle 4 has a U-shaped structure, with one end connected to the self-expanding intramedullary nail 1 in a butt joint manner, and the interior of this section is hollow to facilitate the insertion of the worm gear 21 into the operating cavity of the self-expanding intramedullary nail 1.

[0059] A method of using the above-mentioned controllable self-expanding intramedullary nail internal fixation system for long bone fractures includes the following steps:

[0060] Step 1: Preoperative preparation: Observe the width h of the patient's medullary canal 100 under CT or X-ray. Select a suitable self-expanding intramedullary nail 1 based on the width h of the patient's medullary canal 100. Then, calculate the insertion depth Δ of the drive screw 4 from the medullary canal width h and the single arm length (length of the connecting plate 122) R of the intramedullary nail expandable scaffold 12. The calculation formula is as follows:

[0061] (R-△+x) 2 +h1 2 =R 2

[0062] (Rx) 2 +h1 2 =R 2

[0063] In the formula, x represents the distance the center point of the expandable support 12 moves relative to its original position; h1 is half of h;

[0064] After calculating △, the expansion size of the expandable bracket 12 can be precisely controlled according to the scale 26;

[0065] Specifically, such as Figure 10 As shown, assuming the width of the patient's medullary cavity is 10mm, if a self-expanding intramedullary nail is used, the required expansion height is h1 = 5mm. Given that the expansion frame length of the self-expanding intramedullary nail is R = 15mm, Δ = 1.72mm can be calculated according to the above formula. At this point, the depth to which the drive screw 4 needs to be screwed into the self-expanding intramedullary nail 1 can be known before the operation. This screwing depth can be displayed on the dial 26 on the visual and controllable self-tensioning platform 2. This can avoid causing excessive stimulation to the patient's medullary cavity, thereby protecting the blood supply of the endosteal membrane.

[0066] Step 2: Insert the self-expanding intramedullary nail 1 in its natural state into the long medullary cavity 100; specifically, the insertion handle 5 is connected to the proximal connection hole 14 of the self-expanding intramedullary nail 1 in its natural state, and the side is connected to the proximal aiming bracket 6 through the aiming bracket bolt 8. During the intramedullary nailing surgery, the self-expanding intramedullary nail 1 is inserted into the humeral medullary cavity 100 by tapping or rotating the insertion handle 5. After the self-expanding intramedullary nail 1 is implanted, the expandable bracket 12 is in its natural unexpanded state.

[0067] Step 3: Implant the visual and controllable self-expanding platform 2 into the expandable intramedullary nail 1: Specifically, turn in the limiting rod 27 to lock the visual and controllable self-expanding platform 2, connect the drive screw 4 to the drive worm gear 21 and insert it into the operating cavity; rotate the drive worm gear 21 to connect the drive screw 4 to the distal internal thread 13, continue to rotate the drive worm gear 21 to expand the expandable support 12 until the pointer 25 turns to the predetermined position, then rotate the limiting rod 27 to lock the visual and controllable self-expanding platform 2, and then turn out the visual and controllable self-expanding platform 2.

[0068] Step 4: Insert the locking nail 3 into the locking hole 11 at the tip of the intramedullary nail. Using the aiming hole on the proximal aiming bracket 6 and the locking nail sleeve 7, screw multiple locking nails 3 into the locking hole 11. After screwing them in, drive the screw inner core 33 to open the opening bracket 32 ​​to release the medication. At this point, the implantation is complete. Remove the insertion handle 5 and the proximal aiming bracket 6.

[0069] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A controllable self-expanding intramedullary nail internal fixation system for long bone fractures, characterized in that, include: Self-expanding intramedullary nail (1), visual and controllable self-expanding platform (2), locking nail (3); The self-expanding intramedullary nail (1) includes a locking hole (11) and an expandable scaffold (12); the locking hole (11) is located at the proximal end of the self-expanding intramedullary nail (1) and is adapted to the locking screw (3) to fix the proximal end of the self-expanding intramedullary nail (1); the expandable scaffold (12) is located at the distal end of the self-expanding intramedullary nail (1) and divides the self-expanding intramedullary nail (1) into a proximal segment and a distal segment; The expandable stent (12) includes several expandable connecting plates (121), each expandable connecting plate (121) includes two connecting plates (122), the two connecting plates (122) are bendably connected, and the ends of the two connecting plates (122) are bendably connected to the self-expanding intramedullary nail (1). The self-expanding intramedullary nail (1) has a hollow interior forming an operating cavity; the operating cavity has a distal internal thread (13) in the distal segment and a proximal internal thread (15) in the proximal segment. The visible and controllable self-expanding platform (2) includes a drive worm (21), a worm wheel (22), and a housing (23). The drive worm (21) is meshed with the worm wheel (22) inside the housing (23). Both ends of the drive worm (21) extend outside the housing (23), with one end extending into the operating cavity and connected to the drive screw (4), and the other end used to control rotation. Both ends of the drive screw (4) are threadedly connected to the distal internal thread (13) and the proximal internal thread (15), respectively. A worm wheel shaft (24) is fixedly provided at the center of the worm wheel (22), and a pointer (25) is fixedly provided at the other end of the worm wheel shaft (24). A scale (26) is provided on the pointer (25). A limit rod (27) is provided on the housing (23). The limit rod (27) can lock the worm wheel (22). The depth Δ of the drive screw (4) screwed in is calculated from the medullary cavity width h and the length R of the connecting plate (122). The calculation formula is as follows: (R-△+x) 2 +h1 2 =R 2 (Rx) 2 +h1 2 =R 2 In the formula, x represents the distance the center point of the expandable stent (12) moves relative to its original position; h1 is half of h; After calculating △, the expansion size of the expandable support (12) can be precisely controlled according to the dial (26).

2. The controllable self-expanding intramedullary nail internal fixation system for long bone fractures according to claim 1, characterized in that, The locking hole (11) includes several horizontal locking holes (111) and upward oblique locking holes (112); the opening directions of the several horizontal locking holes (111) are different.

3. The controllable self-expanding intramedullary nail internal fixation system for long bone fractures according to claim 1, characterized in that, The locking pin (3) is a self-expanding locking pin, including a locking pin body (31) and an opening bracket (32); the opening bracket (32) is located at the end of the locking pin body (31) and is driven to expand by a screw core (33) located inside the locking pin body (31); the opening bracket (32) is provided with a drug release hole (34).

4. The controllable self-expanding intramedullary nail internal fixation system for long bone fractures according to claim 1, characterized in that, It also includes an intramedullary nail implantation mechanism; the intramedullary nail implantation mechanism includes an insertion handle (5), a proximal aiming bracket (6), and a locking sleeve (7); one end of the insertion handle (5) can be connected to the proximal connection hole (14) opened at the top of the proximal end of the self-expanding intramedullary nail (1), and the other end is connected to the proximal aiming bracket (6) through the aiming bracket bolt (8); the locking sleeve (7) cooperates with the proximal aiming bracket (6) to screw the locking nail (3) into the locking hole (11).

Images