A medical screw

Abstract

This utility model discloses a medical screw, belonging to the field of medical device technology. It includes a distal screw head, which is tapered and threaded. A distal hexagonal hole is formed at the rear end of the distal screw head. A hexagonal connecting post, shaped like a hexagonal prism, is fitted inside the distal hexagonal hole with a through-hole. A proximal screw body is fitted outside the hexagonal connecting post. The proximal screw body has an internal hexagonal channel with the same shape as the hexagonal connecting post. A ring-shaped suture is connected to the bottom of the distal hexagonal hole, passing through the hexagonal connecting post and exiting from the tail end of the proximal screw body. Using a tensioned ring-shaped suture, the proximal screw body and distal screw head are screwed into the bone as a single unit. Rotation provides pressure fixation. After fixation, the hexagonal connecting post is rotated into the proximal screw body using a specialized screwdriver, resulting in elastic fixation.

Description

Technical Field

[0001] This utility model belongs to the field of medical device technology, specifically relating to a medical screw. Background Technology

[0002] Ankle fractures combined with distal tibiofibular syndesmosis injury and coracoclavicular ligament rupture are common interosseous ligament injuries in clinical practice; among them, ankle fractures combined with distal tibiofibular syndesmosis injury are the most common.

[0003] Clinically, reduction and fixation of the distal tibiofibular syndesmosis ligament or reconstruction of the coracoclavicular ligament are required. For distal tibiofibular syndesmosis injuries and coracoclavicular ligament ruptures, medical practice employs rigid fixation with metal screws or elastic fixation with looped plates, titanium cables / wires, etc. Rigid fixation and elastic fixation each have their own advantages and disadvantages. Rigid fixation provides good stability in the early stages, but restricts micro-movement of the joint. Later complications such as screw breakage and loosening generally require a second surgery to remove the screws. After screw removal, some patients experience re-separation, fixation deviating from clinical expectations, or even surgical failure. Elastic fixation conforms to physiological structure, but current elastic fixation methods mostly use looped plates. A relatively thick bone tunnel needs to be established preoperatively, and the original interosseous anatomical relationship is restored by tightening sutures. The surgical procedure is relatively complex. These drawbacks increase the operation time and trauma.

[0004] Traditional metal screws have the advantages of being simple to operate, easy for clinicians to master, and short operation time in surgery for tibiofibular syndesmosis injuries and coracoclavicular ligament ruptures of the ankle joint; however, rigid fixation is prone to stress shielding effect, which leads to reduced bone density in the fixation area and increases the risk of postoperative complications such as screw loosening and bone resorption. Utility Model Content

[0005] To address the aforementioned problems, this invention proposes a medical screw that provides elastic fixation to the surgical site. It uses a modular design with a distal screw head, a hexagonal connecting post, and a proximal screw body to fix the bone. A high-strength suture connects the hexagonal connecting post and the proximal screw body as a single unit, maintaining the screw's elastic fixation. This adapts to the patient's physiological movements, avoids multiple surgeries, and transmits torque through the hexagonal connecting post by tightening the suture. The integrated proximal and distal screw heads allow the screw's pressure fixation to restore the damaged ligament to its original anatomical position. It retains the advantages of traditional metal screws, such as simple operation and short operation time. The hexagonal connecting post is incorporated into the proximal screw body, and the proximal and distal screw heads are connected by sutures to achieve elastic fixation. This overcomes the limitations of current screws in providing both ease of operation and elastic fixation.

[0006] To achieve the technical objectives described above, this utility model is implemented through the following solution: A medical screw includes a distal screw head, which is shaped like a conical screw to facilitate insertion into the bone requiring fixation. The distal end of the distal screw head has an internal hexagonal hole, into which the front end of a hexagonal connecting post is fitted. The hexagonal connecting post is hexagonal prism-shaped and has a through-hole in the center. A proximal screw body is fitted around the hexagonal connecting post. The outer surface of the proximal screw body is threaded, similar to the surface of the distal screw head, to facilitate fixing the proximal screw body within the bone. The proximal screw body has an internal hexagonal hole with the same shape as the hexagonal connecting post, allowing the proximal screw body to move only along its axial direction after being fitted with the hexagonal connecting post.

[0007] The bottom of the internal hexagonal hole of the distal nail head is connected to a seam thread, which is loop-shaped and passes through the hexagonal connecting post and exits from the tail end of the proximal nail body.

[0008] Furthermore, the rear end of the hexagonal connecting post extends into an internally threaded post head. The outer diameter of the internally threaded post head is smaller than that of the hexagonal connecting post, and its interior is connected to the central channel, which facilitates adjustment at the rear end using a special screwdriver.

[0009] The upper surface of the hexagonal connecting column is provided with a through groove that passes vertically through the central channel;

[0010] A pin hole is provided above the front end of the proximal nail body, and the inner diameter of the pin hole is the same as the radial diameter of the through groove.

[0011] A limiting pin is engaged in the pin hole. The limiting pin can pass through the pin hole and the through groove and can slide along the through groove to prevent the proximal pin body from sliding beyond the maximum distance and slipping off when sliding between the hexagonal connecting post.

[0012] The sewing thread passes through the central channel and is sleeved on the side of the limiting pin. By using a tool to spirally wrap the sewing thread around the tail of the proximal nail head and tightening it as needed, the sewing thread and the limiting pin will generate an interaction force to achieve a fixing effect. In turn, the limiting pin forms an elastic fixation between the proximal nail body and the distal nail head.

[0013] The length of the proximal nail body is greater than that of the hexagonal connecting post, and a proximal internal hexagonal hole is opened inside the rear end of the proximal nail body. The proximal internal hexagonal hole extends backward and is threaded. After the screw is installed, a special screwdriver is used to fix the proximal nail body.

[0014] The beneficial effects of this utility model are:

[0015] 1. By combining the split distal screw head, hexagonal connecting post and proximal screw body, along with the fixation function of the suture, it facilitates operation while providing elastic support for the damaged ligament, effectively alleviating the stress shielding effect of traditional rigid screws, reducing bone density loss and the risk of postoperative loosening and fracture, and avoiding secondary surgery.

[0016] 2. By connecting the proximal and distal screw bodies with a hexagonal connecting post, an integrated screw is formed. In surgeries such as distal tibiofibular syndesmosis injury and coracoclavicular ligament rupture reconstruction, it can provide the compression fixation of ordinary screws and restore the anatomical position of the injured ligament. It has the advantages of traditional metal screws, such as simple operation, short operation time, and minimal trauma. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the embodiments are briefly introduced below.

[0018] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of this utility model;

[0019] Figure 2 This is a schematic diagram of the structure of each part of Embodiment 1 of this utility model;

[0020] Figure 3 This is a schematic diagram of the distal nail body structure of Embodiment 1 of this utility model;

[0021] Figure 4 This is a rear view of Embodiment 1 of this utility model;

[0022] Figure 5 yes Figure 4 A cross-sectional view of surface A.

[0023] The structural names represented by each number in the attached diagram are as follows:

[0024] 1-Distal pin head, 101-Distal internal hexagonal hole, 2-Hexagonal connecting post, 201-Internal threaded post head, 202-Central channel, 203-Through groove, 3-Proximal pin body, 301-Internal hexagonal channel, 302-Pin hole, 303-Proximal internal hexagonal hole, 304-Proximal internal thread, 4-Sewing line, 5-Limiting pin. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments.

[0026] Example 1

[0027] This embodiment provides a medical screw, such as Figures 1 to 5As shown, the medical screw adopts a split design, including a distal screw head 1, a hexagonal connecting post 2, a proximal screw body 3, a suture line 4, and a limiting pin 5. The distal screw head 1 is a tapered threaded screw with external threads on its surface for easy insertion into the bone. A distal internal hexagonal hole 101 is provided at the rear end of the distal screw head 1 for connecting the front end of the hexagonal connecting post 2. The hexagonal connecting post 2 is a hexagonal prism with a through-hole central channel 202. Its rear end extends into a smaller-diameter internally threaded post head 201, which communicates with the central channel 202 for easy rotational adjustment using a special tool. A vertical through-slot 203 is provided on the upper surface of the hexagonal connecting post 2, penetrating the central channel 202. This slot engages with the pin hole 302 of the proximal screw body 3 to limit axial movement.

[0028] The outer surface of the proximal nail body 3 is similar to that of the distal nail head 1, featuring a threaded structure. The proximal nail body 3 has an internal hexagonal channel 301 that matches the shape of the hexagonal connecting post 2, allowing the hexagonal connecting post 2 to slide only along the axial direction of the proximal nail body 3. A pin hole 302 is located above the front end of the proximal nail body 3, with an inner diameter matching the radial diameter of the through-slide groove 203. A limiting pin 5 is engaged within the pin hole 302, passing through the through-slide groove 203 to form a sliding key connection. This allows for limited sliding between the proximal nail body 3 and the hexagonal connecting post 2 while preventing complete separation. The rear end of the proximal nail body 3 has a proximal internal hexagonal hole 303, with a proximal internal thread 304 extending rearward for final tightening using a dedicated screwdriver.

[0029] The suture wire 4 is made of high-strength medical-grade polymer material (such as ultra-high molecular weight polyethylene) or metal alloy wire and has a ring structure. One end of the suture wire 4 is fixed to the bottom of the distal hexagonal hole 101 of the distal nail head 1, and the other end passes through the middle channel 202 of the hexagonal connecting post 2 and exits from the tail end of the proximal nail body 3, and finally fits on both sides of the limiting pin 5. By rotating the adjustment tool at the tail of the proximal nail body 3, a preload can be applied to the suture wire 4 to form a dynamic connection with the limiting pin 5, thereby providing elastic support between the distal nail head 1 and the proximal nail body 3.

[0030] Before surgery, a suitable diameter (e.g., 4.0mm, 3.5mm) and length of medical screw needs to be selected based on the patient's skeletal anatomical parameters (such as cortical bone thickness and ligament length). For acromioclavicular joint dislocation or distal tibiofibular syndesmosis, smaller diameter screws are usually chosen. Under image guidance, a guide pin is inserted to the target bone location to reduce the dislocated joint or fracture site. For example, in coracoclavicular ligament reconstruction, the guide pin needs to pass through the clavicle and coracoid process; in distal tibiofibular syndesmosis fixation, the guide pin needs to pass through the fibula and tibia.

[0031] Before implanting the screw, insert the front end of the hexagonal connecting post 2 into the distal hexagonal hole 101 of the distal screw head 1 to ensure a tight fit. Then, fit the proximal screw body 3 onto the outside of the hexagonal connecting post 2. At this time, the limiting pin 5 passes through the pin hole 302 and the through groove 203 to limit the sliding range of the proximal screw body 3. Then, adjust the preload of the suture 4 and use a tool to pull the tail end of the suture 4 so that it wraps around both sides of the limiting pin 5 and applies appropriate tension to form an integrated connection. Finally, use a special screwdriver to screw the entire screw into the bone and apply pressure fixation to restore the original anatomical position of the damaged ligament. Adjust the screw using the proximal hexagonal hole 303 and the proximal internal thread 304 to retract the hexagonal connecting post 2 into the proximal screw body 3. Form an elastic connection through the suture 4 to complete the fixation surgery.

[0032] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit the protection scope of this utility model. For those skilled in the art, various modifications and variations can be made to the above embodiments without departing from the principle of this utility model, and all such modifications and variations should fall within the protection scope of this utility model.

Claims

1. A medical screw, comprising a distal screw head (1), characterized in that: The distal nail head (1) is in the shape of a conical threaded nail. A distal internal hexagonal hole (101) is provided at the rear end of the distal nail head (1). The front end of a hexagonal connecting post (2) is sleeved in the distal internal hexagonal hole (101). The hexagonal connecting post (2) is in the shape of a hexagonal prism and has a through-hole (202) in the middle. A proximal nail body (3) is sleeved on the outside of the hexagonal connecting post (2). The outer surface of the proximal nail body (3) is the same as the surface of the distal nail head (1) and is threaded. The proximal nail body (3) has a distal hexagonal hole (101) with the same shape as the hexagonal connecting post (2) inside, so that the proximal nail body (3) can only move along the axial direction of the proximal nail body (3) after it is sleeved with the hexagonal connecting post (2); the bottom of the distal hexagonal hole (101) of the distal nail head (1) is connected to a sewing line (4), the sewing line (4) is in the shape of a ring, the sewing line (4) passes through the hexagonal connecting post (2) and comes out from the tail end of the proximal nail body (3).

2. The medical screw according to claim 1, characterized in that: The rear end of the hexagonal connecting post (2) extends into an internally threaded post head (201). The outer diameter of the internally threaded post head (201) is smaller than that of the hexagonal connecting post (2) and its interior is connected to the central channel (202).

3. The medical screw according to claim 2, characterized in that: The upper surface of the hexagonal connecting column (2) is provided with a through groove (203) that passes vertically through the central channel (202).

4. The medical screw according to claim 3, characterized in that: A pin hole (302) is provided above the front end of the proximal nail body (3), and the inner diameter of the pin hole (302) is the same as the radial diameter of the through groove (203).

5. The medical screw according to claim 4, characterized in that: A limiting pin (5) is engaged in the pin hole (302). The limiting pin (5) passes through the pin hole (302) and is connected to the key of the through groove (203). The limiting pin (5) restricts the slippage between the proximal nail body (3) and the hexagonal connecting post (2).

6. The medical screw according to claim 5, characterized in that: The sewing line (4) passes through the central channel (202) and is sleeved on both sides of the limiting pin (5). After being tightened, the sewing line (4) can form an elastic fixation between the limiting pin (5) and the distal nail head (1).

7. The medical screw according to claim 1, characterized in that: The length of the proximal nail body (3) is greater than that of the hexagonal connecting post (2), and a proximal internal hexagonal hole (303) is provided inside the rear end of the proximal nail body (3), and a proximal internal thread (304) is provided on the rearward extension of the proximal internal hexagonal hole (303).

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