Removable screw and internal fixation device for anterior pelvic ring fixation

Abstract

The present invention provides a detachable screw and internal fixation device for fixing the anterior pelvic ring. The screw includes a main nail, a nail barrel, a fixing member, and an internal screw. The through hole in the nail barrel is stepped, including a first through hole connected to the main nail and a second through hole with a diameter larger than the first through hole. The first and second through holes are respectively away from and close to the main nail. The main nail includes a nail tail and a nail rod and is integrally formed. The nail tail can pass through the second through hole. The inner wall of the first through hole in the nail barrel is provided with an internal thread, and the internal screw is connected to the nail barrel via the internal thread. The fixing member is disposed in the nail barrel and located between the nail tail and the internal screw. The fixing member retains the nail tail in the nail barrel through the fixing member. The fixing member includes a support portion and a plurality of arc-shaped spring pieces fixed to one end of the support portion near the nail tail and arranged circumferentially along the support portion. The arc center of the arc faces the nail tail, and the plurality of spring pieces tighten or loosen the nail tail. The internal fixation device includes a connecting crossbar and at least two of the above-mentioned screws. The screws are connected by the connecting crossbar, thereby reducing postoperative discomfort.

Description

Technical Field

[0001] The present invention relates to the technical field of orthopedic medical devices, and in particular to a detachable screw and an internal fixation device for fixing an anterior pelvic ring. Background Art

[0002] For elderly patients with fragile anterior pelvic ring injuries, minimally invasive percutaneous anterior pelvic ring internal fixation (Minimally Invasive Anterior Pelvic Ring Internal Fixator) is currently commonly used clinically. The most widely used and effective device in this procedure is called an internal fixator (INFIX). The original design of the internal fixator was to stabilize the anterior pelvic ring, so anterior pelvic ring injuries, including pubic symphysis separation and pubic ramus fractures, are its best indications. Because the internal fixator is located in the lower abdomen and anterior pelvic ring, thin patients will experience subjective discomfort, especially in the sitting position. Subjective discomfort usually occurs after surgery and affects daily life, but this discomfort disappears after the internal fixator is removed. Therefore, after the fracture heals, a second surgery should be performed to remove the internal fixator.

[0003] Currently, the main screw and the cap connecting the crossbar are integrated into the internal fixator design. However, some fractures require the main screw to remain in place for a long time, and the crossbar causes discomfort, necessitating early removal. However, in the early stages after anterior pelvic ring injury rehabilitation surgery, the pelvis is not fully healed, making it difficult to remove the remaining screws except for the main screw.

[0004] In the prior art, there is no effective solution to the problem that it is difficult to remove the remaining parts of the internal fixator except the main nail for patients who have installed the internal fixator. Summary of the Invention

[0005] In view of this, the present invention provides a detachable screw and an internal fixation device for fixing the anterior pelvic ring, which solves the problem in the prior art that it is difficult to remove the remaining parts outside the main screw for patients who have installed an internal fixator.

[0006] To this end, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a detachable screw for fixing the anterior pelvic ring, comprising: a main screw, a screw barrel, a fixing member, and an inner screw;

[0008] The through hole in the nail barrel is stepped, including a first through hole and a second through hole in communication, the first through hole being away from the main nail, the second through hole being close to the main nail, the diameter of the first through hole being larger than the diameter of the second through hole, the main nail including a nail tail and a nail rod, the nail tail and the nail rod being integrally formed, and the nail tail being able to pass through the second through hole;

[0009] The inner wall of the first through hole of the nail barrel is provided with an internal thread, and the internal screw is connected to the nail barrel through the internal thread;

[0010] The fixing member is arranged in the nail barrel and is located between the nail tail and the inner screw. The nail tail is retained in the nail barrel by the fixing member. The fixing member includes a support portion and a plurality of spring leaves fixed to the support portion at one end near the nail tail. The plurality of spring leaves are arranged circumferentially along the support portion. The spring leaves are arc-shaped, with the center of the arc facing the nail tail. The plurality of spring leaves include a first state in which the nail tail is tightly clamped when the inner screw is screwed into the nail barrel and a second state in which the nail tail is loosened when the inner screw is screwed out of the nail barrel.

[0011] Optionally, the thread on the nail rod includes a coarse thread and a fine thread, the coarse thread is close to the nail tail, and the fine thread is far away from the nail tail.

[0012] Optionally, a cavity is provided inside the main nail, and the cavity passes through the main nail.

[0013] Optionally, a side wall of the nail rod away from the nail tail is provided with a plurality of injection holes, and the injection holes are communicated with the cavity.

[0014] Optionally, the nail rod is provided with a plurality of receiving grooves along the circumference, and a protruding cutting edge is provided in the receiving groove, and the cutting edge is used to cut the bone when the main nail is rotated.

[0015] In a second aspect, the present invention provides an internal fixation device, comprising a connecting crossbar and at least two detachable screws for fixing the anterior pelvic ring according to any one of the first aspects, wherein the detachable screws for fixing the anterior pelvic ring are connected by the connecting crossbar;

[0016] Two opposite slots are provided on the side wall of the nail barrel away from the main nail, and the connecting cross bar is inserted into the slots. The connecting cross bar is fixed between the fixing piece and the inner screw.

[0017] Optionally, a limiting groove is provided on the end surface of the fixing member away from the main nail, and the connecting cross bar matches the limiting groove.

[0018] Optionally, the connecting cross bar includes an elastic portion and a rigid portion, and the elastic portion and the rigid portion are alternately connected.

[0019] Optionally, the elastic part is a spring, and two ends of the spring are respectively fixedly connected to the rigid part.

[0020] The technical solution of the present invention has the following advantages:

[0021] The present invention provides a detachable screw and an internal fixation device for fixing the anterior pelvic ring. The present invention solves the problem in the prior art that it is difficult for patients with an internal fixator to remove the rest of the screw except the main screw. In the present invention, the fixing part is squeezed by the internal screw, so that the spring leaf on the fixing part is compressed and deformed, and then the tail of the main nail is tightly embraced, so that the entire screw is firmly fixed at the anterior pelvic ring; and by removing the inner screw on the detachable screw for fixing the anterior pelvic ring, the spring leaf on the fixing part returns to its natural state, and the tail of the main nail can be detached from the multiple spring leaves, thereby realizing the removal of the detachable screw for fixing the anterior pelvic ring. Therefore, when the main nail does not need to be removed, the rest of the detachable screw for fixing the anterior pelvic ring except the main nail can be removed, thereby reducing the patient's postoperative discomfort. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 is a schematic structural diagram of a detachable screw for fixing the anterior pelvic ring according to the present invention;

[0024] Figure 2 is a schematic structural diagram of a main nail according to the present invention;

[0025] Figure 3 It is a structural schematic diagram of a nail barrel according to the present invention;

[0026] Figure 4 is a schematic structural diagram of a fixing member according to the present invention;

[0027] Figure 5 is a cross-sectional view along the length direction of the main nail when the fixing member according to the present invention is in a first state;

[0028] Figure 6 is a cross-sectional view along the length direction of the main nail when the fixing member according to the present invention is in the second state;

[0029] Figure 7 2. It is a schematic structural diagram of a main nail provided with a cutting edge according to the present invention;

[0030] Figure 8 is a schematic structural diagram of an internal fixation device according to the present invention;

[0031] Figure 9 2 is a schematic structural diagram of a connecting cross bar according to the present invention.

[0032] In the figure,

[0033] 1. Main nail; 11. Nail tail; 111. Cavity; 12. Nail rod; 121. Coarse thread; 122. Fine thread; 123. Injection hole; 124. Receiving groove; 125. Cutting edge; 2. Nail barrel; 21. Internal thread; 22. Slot; 3. Fixing part; 31. Support part; 32. Spring leaf; 33. Limiting groove; 4. Internal screw; 5. Connecting cross bar; 51. Elastic part; 52. Rigid part. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0036] In the present invention, the word "exemplary" is used to mean "serving as an example, illustration or description". Any embodiment described in the present invention as "exemplary" is not necessarily to be construed as being preferred or advantageous over other embodiments. The following description is given to enable any person skilled in the art to implement and use the present invention. In the following description, details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present invention can be implemented without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of the present invention with unnecessary details. Therefore, the present invention is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles and features disclosed herein.

[0037] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0038] The present invention provides a detachable screw and an internal fixation device for fixing the anterior pelvic ring, which can be used for postoperative fixation of anterior pelvic ring injuries, such as postoperative fixation of symphysis pubis separation and postoperative fixation of pubic ramus fracture. Figure 1 Schematic diagram of the structure of the detachable screw for fixing the anterior pelvic ring according to the present invention, as shown in FIG. Figure 1 As shown, the detachable screw for fixing the anterior pelvic ring includes: a main nail 1, a nail barrel 2, a fixing piece 3, and an inner screw 4. Specifically, by connecting the main nail 1, the nail barrel 2, the fixing piece 3, and the inner screw 4, a detachable screw for fixing the anterior pelvic ring is formed. The detachable screw for fixing the anterior pelvic ring is placed at the site of a pelvic fracture to effectively fix the fracture.

[0039] like Figure 2 and Figure 3 As shown, the through hole in the nail barrel 2 is stepped, including a first through hole and a second through hole that are connected. The first through hole is away from the main nail 1, and the second through hole is close to the main nail 1. The diameter of the first through hole is larger than the diameter of the second through hole. The main nail 1 includes a nail tail 11 and a nail rod 12. The nail tail 11 and the nail rod 12 are integrally formed, and the nail tail 11 can pass through the second through hole. Specifically, when removing the detachable screw for fixing the anterior pelvic ring, since the nail tail 11 can pass through the second through hole, the main nail 1 can be detached from the nail barrel 2 without restriction. In other words, when the main nail 1 is fixed in the bone, the nail barrel 2 moves away from the bone along the length of the main nail 1, and the nail tail 11 passes through the first through hole and the second through hole, and the nail barrel 2 is separated from the nail tail 11.

[0040] The inner wall of the first through hole of the nail barrel 2 is provided with an internal thread 21, and the internal screw 4 is connected to the nail barrel 2 through the internal thread 21; the fixing member 3 is arranged in the nail barrel 2 and is located between the nail tail 11 and the internal screw 4, and the nail tail 11 is retained in the nail barrel 2 by the fixing member 3, and the fixing member 3 includes a support portion 31 and a plurality of spring pieces 32 fixed to one end of the support portion 31 close to the nail tail 11. The plurality of spring pieces 32 are arranged circumferentially along the support portion 31, and the spring pieces 32 are arc-shaped, with the arc center facing the nail tail 11, as shown in FIG. Figure 4 As shown, the plurality of spring pieces 32 include a first state (such as Figure 5 ) and the second state of loosening the nail tail 11 when the inner screw 4 is screwed out of the nail barrel 2 (as shown in FIG. Figure 6As shown). Specifically, the fixing member 3 is installed in the nail barrel 2, and then the fixing member 3 is restricted in the nail barrel 2 by the inner screw 4. At this time, the inner screw 4 does not squeeze the fixing member 3, and the multiple spring pieces 32 on the fixing member 3 will not squeeze the nail barrel 2 and deform, and the fixing member 3 is in the second state; because the fixing member 3 is in the second state, the nail tail 11 of the main nail 1 can pass through the second through hole and extend between the multiple spring pieces 32. At the same time, since the length of each spring piece 32 in the natural state is greater than the length of the nail tail 11, the multiple spring pieces 32 can wrap the nail tail 11, and at this time the multiple spring pieces 32 do not hold the nail tail 11 tightly, so that the nail tail 11 can fall out from between the multiple spring pieces 32 and then break away from the nail barrel 2. Then, the fixing member 3 is squeezed by the inner screw 4, so that the fixing member 3 moves in the direction of the main nail 1. When the multiple When the spring pieces 32 come into contact with the bottom wall of the nail barrel 2, the bottom wall of the nail barrel 2 hinders the movement of the fixing member 3. However, as the inner screw 4 continues to squeeze the fixing member 3, the multiple spring pieces 32 are affected by the bottom wall of the nail barrel 2, and the bending of the multiple spring pieces 32 is aggravated, so that the abdomen of the multiple spring pieces 32 approaches the side wall of the nail barrel 2, and the end of the spring piece 32 away from the support portion 31 is bent and deformed along the length direction, and then the end of the multiple spring pieces 32 away from the support portion 31 approaches the support portion 31, and the multiple spring pieces 32 hold the nail tail 11 tightly, and the fixing member 3 is in the first state. At this time, it is difficult for the nail tail 11 to separate from the multiple spring pieces 32, forming a detachable screw for fixing the anterior pelvic ring; moreover, the multiple spring pieces 32 also fill the gap between the nail barrel 2 and the nail tail 11, preventing the nail tail 11 from shaking in the nail barrel 2, and the fixation is relatively firm. After the detachable screw for fixing the anterior pelvic ring is placed in the patient's fracture, when it is necessary to remove the rest of the parts except the main nail 1, the inner screw 4 is removed, and the fixing part 3 moves away from the main nail 1, so that the effect of the bottom wall of the nail tube 2 on the multiple spring leaves 32 is reduced, and the multiple spring leaves 32 gradually return to their natural state. Finally, the fixing part 3 returns to the second state, and the nail tail 11 can be detached from the multiple spring leaves 32, thereby retaining the main nail 1 in the patient's fracture and realizing the removal and removal of the detachable screw for fixing the anterior pelvic ring.

[0041] When the fixing member 3 is in the first state or the natural state, the diameter of the area enclosed by the multiple spring leaves 32 near the end of the main nail 1 is slightly smaller than the maximum diameter of the nail tail 11, but larger than the diameter of the nail shank 12. Because the spring leaves 32 have elastic force, when the nail tail 11 is extended from the area enclosed by the multiple spring leaves 32 near the end of the main nail 1 into the space enclosed by the multiple spring leaves 32, the multiple spring leaves 32 can expand toward the side away from the arc center, allowing the nail tail 11 to extend into the space enclosed by the multiple spring leaves 32. However, because the diameter of the nail shank 12 is smaller than the diameter of the area enclosed by the multiple spring leaves 32 near the end of the main nail 1, the multiple spring leaves 32 no longer deform and return to their initial position. At this time, the nail tail 11 is located in the space enclosed by the multiple spring leaves 32 and is not easily separated from the fixing member 3 when no force is applied.

[0042] Prior art screws for pelvic fractures lack removable features, typically employing a single-piece main screw and barrel. Consequently, the barrel cannot be removed during pelvic fracture screw removal. This embodiment, unlike prior art, offers a removable screw for anterior pelvic ring fixation. Because the tail 11 of the main screw 1 can pass through a second through-hole, the barrel 2 and fixing member 3 can be removed while retaining the main screw 1. This embodiment addresses the prior art issue of difficulty removing the rest of the screw, other than the main screw 1, for patients with internal fixators, thereby minimizing postoperative discomfort.

[0043] To illustrate the threads on the nail shank 12, in some optional embodiments, the threads on the nail shank 12 include a coarse thread 121 and a fine thread 122, with the coarse thread 121 located closer to the nail tail 11 and the fine thread 122 located further away. Specifically, the coarse thread 121 offers high strength and excellent fixation, while the fine thread 122 provides excellent sealing. Without anti-loosening measures, the fine thread 122 offers superior anti-loosening performance compared to the coarse thread 121, but the fine thread 122 exhibits lower strength. Therefore, configuring the threads on the nail shank 12 as coarse threads 121 and fine threads 122 can effectively enhance the gripping force of the main nail 1. Those skilled in the art should understand that configuring the threads on the nail shank 12 as coarse threads 121 and fine threads 122 does not limit the present invention; other types of threads are also within the scope of protection of the present invention, such as providing fine threads 122 between the coarse threads 121.

[0044] To illustrate the main nail 1, in some optional embodiments, a cavity 111 is provided inside the main nail 1, and the cavity 111 passes through the main nail 1. Providing the cavity 111 inside the main nail 1 can release the pressure at the fracture site, allowing the fracture site to recover better. In addition, a Kirschner wire can pass through the cavity 111 on the main nail 1, and then the Kirschner wire can be used to guide the main nail 1, so that the main nail 1 can be accurately placed in the pelvic fracture site, effectively promoting the fixation of the pelvic fracture by the main nail 1. Specifically, when guiding with the Kirschner wire, a Kirschner wire is first inserted into the fracture site, and then the main nail 1 is passed through the Kirschner wire, and then the detachable screw for fixing the anterior pelvic ring is placed in the position where the Kirschner wire is located, and finally the Kirschner wire is withdrawn.

[0045] To further illustrate the main nail 1, in some optional embodiments, a plurality of injection holes 123 are provided on the side wall of the nail rod 12 at one end away from the nail tail 11, and the injection holes 123 are connected to the cavity 111. After the main nail 1 is placed in the pelvic fracture, bone cement can be injected into the cavity 111 from the tail of the main nail 1. The bone cement can enter the pelvic fracture through the injection holes 123, which is beneficial to the recovery of the pelvic fracture. At the same time, because the elderly usually suffer from osteoporosis, the degree of bone damage is relatively severe when a fracture occurs. By inserting bone cement into the main nail 1, the mechanical strength of the main nail 1 can be improved, which is beneficial to the postoperative recovery of the fracture.

[0046] In other optional embodiments, such as Figure 6 As shown, the nail rod 12 is provided with a plurality of receiving grooves 124 along the circumference, and the receiving grooves 124 are provided with raised cutting edges 125. The cutting edges 125 are used to cut bone when the main nail 1 is rotated. After the main nail 1 has been placed in the patient's pelvic fracture for a period of time, the patient's pelvic fracture needs to be removed after the patient's pelvic fracture has healed. However, since the bone around the main nail 1 gradually heals, it hinders the removal of the main nail 1, making the main nail 1 susceptible to damage. The cutting edges 125 can cut the bone around the main nail 1 when the main nail 1 is rotated, and the cut bone debris enters the receiving grooves 124, thereby facilitating the removal of the main nail 1. When the main nail 1 is removed, the bone debris is taken out, preventing the main nail 1 from being damaged.

[0047] This embodiment also provides an internal fixation device, such as Figure 7 As shown, the internal fixation device includes a connecting crossbar 5 and at least two detachable screws for fixing the anterior pelvic ring according to any of the above embodiments, wherein the detachable screws for fixing the anterior pelvic ring are connected by the connecting crossbar 5. The connecting crossbar 5 is used to connect multiple detachable screws for fixing the anterior pelvic ring to form an internal fixation device, which can effectively fix the fractured bone.

[0048] Two opposing slots 22 are provided on the side wall of the nail barrel 2, away from the main nail 1. The connecting crossbar 5 is snapped into the slots 22, and the connecting crossbar 5 is fixed between the fixing member 3 and the inner screw 4. By providing two opposing slots 22 on the nail barrel 2, and by matching the slots 22 with the connecting crossbar 5, the connecting crossbar 5 can be snapped into the slots 22. Specifically, the fixing member 3 is installed into the nail barrel 2, the connecting crossbar 5 is snapped into the slots 22, and then the nail tail 11 of the main nail 1 is placed between the multiple spring leaves 32. Finally, the inner screw 4 is screwed in to squeeze the connecting crossbar 5 and the fixing member 3, so that the fixing member 3 is in the first state, holding the nail tail 11 tightly, and forming the internal fixation device. After the internal fixation device is placed in the patient's fracture site, the nail barrel 2, fixing member 3, inner screw 4, and connecting crossbar 5 can be removed while retaining the main nail 1, thereby reducing the patient's discomfort without affecting recovery.

[0049] To illustrate the fixing member 3, in some optional embodiments, a limiting groove 33 is provided on the end surface of the fixing member 3 away from the main nail 1, and the connecting cross bar 5 matches the limiting groove 33. Since the fixing member 3 is provided with the limiting groove 33 matching the connecting cross bar 5, the connecting cross bar 5 can be effectively fixed.

[0050] To illustrate the connecting crossbar 5, in some optional embodiments, such as Figure 8 As shown, the connecting crossbar 5 includes an elastic portion 51 and a rigid portion 52, which are alternately connected. Specifically, when connecting the connecting crossbar 5 to multiple detachable screws for fixing the anterior pelvic ring, the rigid portion 52 of the connecting crossbar 5 is engaged in the slot 22, preventing the connecting crossbar 5 from being separated from the nail barrel 2. At the same time, the elastic portion 51 between the two rigid portions 52 can bend the connecting crossbar 5. When the internal fixation device is inserted, the elastic portion 51 can bend the connecting crossbar 5, allowing the nail rod 12 of the main nail 1 to be nailed into the appropriate position, thereby achieving a better fixation effect on the pelvic fracture.

[0051] To further illustrate the connecting crossbar 5, in some optional embodiments, the elastic portion 51 is a spring, and the two ends of the spring are respectively fixedly connected to the rigid portion 52. The action of the spring can cause the connecting crossbar 5 to bend, facilitating fixation of the fracture by the internal fixation device. Those skilled in the art should understand that the elastic portion 51 being a spring does not limit the present invention. Elastic portions 51 composed of other structures or materials are also within the scope of protection of the present invention, such as silicone rods and rod-shaped structures formed by metal mesh.

[0052] In some possible embodiments, the patient's fracture is fixed using an internal fixation device, and the specific process is as follows:

[0053] (1) Since a hexagonal through hole is provided on the nail tail 11 of the main nail 1, multiple main nails 1 are respectively nailed into the patient's fracture site using a hexagonal wrench that matches the hexagonal through hole;

[0054] (2) Slide the nail barrel 2 onto the nail tail 11 of the main nail 1, and let the nail tail 11 pass through the second through hole and enter the nail barrel 2;

[0055] (3) Install the fixing member 3 into the nail barrel 2 through the first through hole, and slightly squeeze the fixing member 3. The multiple spring pieces 32 on the fixing member 3 squeeze the nail tail 11, so that the ends of the multiple spring pieces 32 away from the support portion 31 approach the inner wall of the nail barrel 2. As the fixing member 3 moves toward the main nail, the multiple spring pieces 32 surround the nail tail 11.

[0056] (4) Place the connecting crossbar 5 in the limiting groove 33 of the fixing member 3, and snap the connecting crossbar 5 into the two opposite slots 22 on the side wall of the nail barrel 2;

[0057] (5) The inner screw 4 is screwed into the nail barrel through the inner thread 21 provided on the inner wall of the first through hole of the nail barrel 2. As the inner screw 4 is screwed in, the inner screw 4 squeezes the connecting cross bar 5, and then squeezes the fixing member 3. The multiple spring leaves 32 are affected by the bottom wall of the nail barrel 2, and the bending of the multiple spring leaves 32 is aggravated, so that the abdomen of the multiple spring leaves 32 approaches the side wall of the nail barrel 2. The end of the spring leaf 32 away from the support portion 31 is bent and deformed along the length direction, and then the end of the multiple spring leaves 32 away from the support portion 31 approaches the support portion 31. The multiple spring leaves 32 hold the nail tail 11 tightly until the fixing member 3 is in the first state, and the nail tail 11 is confined in the nail barrel 2.

[0058] In some possible embodiments, the main nail 1 is retained at the patient's fracture site, and the remaining components other than the main nail 1 are removed. The specific process is as follows:

[0059] (1) Unscrew the inner screw 4 from the inner thread 21 and move the fixing member 3 away from the main nail 1 until the fixing member 3 is in the second state;

[0060] (2) Remove the connecting cross bar 5 from the two opposite slots 22 on the side wall of the nail barrel 2 and disengage it from the limiting slot 33 of the fixing member 3, and then remove the connecting cross bar 5 from the patient's body;

[0061] (3) Pull up the fixing piece 3 with a slight force. The multiple spring pieces 32 on the fixing piece 3 near the main nail are deformed and move toward the side wall of the nail barrel 2. The multiple spring pieces 32 near the main nail open and detach from the nail tail 11. Remove the fixing piece 3.

[0062] (4) Pull out the nail barrel 2 directly.

[0063] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A detachable screw for fixing the anterior pelvic ring, characterized in that: include: Main nail (1), nail barrel (2), fixing piece (3) and inner screw (4); The through hole in the nail barrel (2) is stepped, comprising a first through hole and a second through hole that are connected, wherein the first through hole is away from the main nail (1), and the second through hole is close to the main nail (1), the diameter of the first through hole is larger than the diameter of the second through hole, and the main nail (1) comprises a nail tail (11) and a nail rod (12), wherein the nail tail (11) and the nail rod (12) are integrally formed, and the nail tail (11) can pass through the second through hole; The inner wall of the first through hole of the nail barrel (2) is provided with an internal thread (21), and the internal screw (4) is connected to the nail barrel (2) via the internal thread (21); The fixing member (3) is arranged in the nail barrel (2) and is located between the nail tail (11) and the inner screw (4). The nail tail (11) is retained in the nail barrel (2) by the fixing member (3). The fixing member (3) includes a support portion (31) and a plurality of spring pieces (32) fixed to one end of the support portion (31) close to the nail tail (11). The plurality of spring pieces (32) are arranged circumferentially along the support portion (31). The spring pieces (32) are arc-shaped, with the arc center facing the nail tail (11). The plurality of spring pieces (32) include a first state in which the nail tail (11) is tightly held when the inner screw (4) is screwed into the nail barrel (2) and a second state in which the nail tail (11) is loosened when the inner screw (4) is screwed out of the nail barrel (2). When the fixing member (3) is in the first state, the diameter of the area enclosed by the plurality of spring sheets (32) close to one end of the main nail (1) is slightly smaller than the maximum diameter of the nail tail (11), but larger than the diameter of the nail rod (12).

2. The detachable screw for fixing the anterior pelvic ring according to claim 1, characterized in that: The threads on the nail rod (12) include coarse threads (121) and fine threads (122), wherein the coarse threads (121) are close to the nail tail (11), and the fine threads (122) are far away from the nail tail (11).

3. The detachable screw for fixing the anterior pelvic ring according to claim 1, characterized in that: A cavity (111) is provided inside the main nail (1), and the cavity (111) passes through the main nail (1).

4. The detachable screw for fixing the anterior pelvic ring according to claim 3, characterized in that: A plurality of injection holes (123) are provided on the side wall of one end of the nail rod (12) away from the nail tail (11), and the injection holes (123) are communicated with the cavity (111).

5. The detachable screw for fixing the anterior pelvic ring according to claim 1, characterized in that: The nail rod (12) is provided with a plurality of receiving grooves (124) along the circumference, and a protruding cutting edge (125) is provided in the receiving groove (124). The cutting edge (125) is used to cut bones when the main nail (1) is rotated.

6. An internal fixation device, characterized in that: It comprises a connecting cross bar (5) and at least two detachable screws for fixing the anterior pelvic ring according to any one of claims 1 to 5, wherein the detachable screws for fixing the anterior pelvic ring are connected via the connecting cross bar (5); Two opposite slots (22) are provided on the side wall of the nail barrel (2) away from the main nail (1), and the connecting cross bar (5) is inserted into the slots (22). The connecting cross bar (5) is fixed between the fixing member (3) and the inner screw (4).

7. The internal fixation device according to claim 6, characterized in that: A limiting groove (33) is provided on the end surface of the fixing member (3) away from the main nail (1), and the connecting cross bar (5) matches the limiting groove (33).

8. The internal fixation device according to claim 6, wherein: The connecting cross bar (5) comprises an elastic portion (51) and a rigid portion (52), and the elastic portion (51) and the rigid portion (52) are alternately connected.

9. The internal fixation device according to claim 8, characterized in that: The elastic part (51) is a spring, and the two ends of the spring are respectively fixedly connected to the rigid part (52).

Images