Removable screws and internal fixation device for anterior ring fixation of pelvic fracture

Abstract

The present invention provides a detachable screw for fixing anterior ring of pelvic fracture and an internal fixation device, wherein the detachable screw for fixing anterior ring of pelvic fracture comprises: a main nail, a nail tube and a limiting mechanism; the through hole in the nail tube is stepped; the nail head of the main nail is placed in the nail tube, the nail rod of the main nail passes through the through hole, the limiting mechanism is detachably connected in the nail tube, and the limiting mechanism is used to limit the rotation of the main nail; when the detachable screw for fixing anterior ring of pelvic fracture is removed, the limiting mechanism is disengaged from the through hole, and the main nail is disengaged from the nail tube after rotating a preset angle. The internal fixation device comprises a connecting cross bar and at least two of the above-mentioned detachable screws for fixing anterior ring of pelvic fracture; the detachable screws for fixing anterior ring of pelvic fracture are connected by a connecting cross bar. The present invention solves the problem in the prior art that it is difficult to remove the rest of the screws other than the main nail for patients with an internal fixator installed, thereby reducing the patient's postoperative discomfort under the premise of retaining the main nail.

Description

Technical Field

[0001] The invention relates to the technical field of orthopedic medical instruments, and in particular to a detachable screw and an internal fixation device for fixing an anterior ring of a pelvic fracture. 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 used clinically. The most widely used and effective device in this procedure is called an internal fixator (INFIX). The original intention 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 front of the lower abdomen and pelvis, thin patients will experience subjective discomfort, especially for sitting position. Subjective discomfort usually occurs after surgery and affects daily life, but the discomfort disappears after the internal fixator is removed. Therefore, after the fracture heals, a second operation should be performed to remove the internal fixator.

[0003] At present, the main screw of the internal fixator and the screw cap connecting the crossbar are an integrated design, but some special fractures require the main screw to be left in place for a long time, and the crossbar causes discomfort and needs to be removed early. However, in the early stage after the rehabilitation surgery of the anterior pelvic ring injury, the pelvis is not fully recovered, and the rest of the screws except the main screw are not easy to remove.

[0004] In view of the problem in the prior art that it is difficult to remove the remaining parts of the screws other than the main screw for patients with internal fixators, no effective solution has been proposed. 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 ring of a pelvic fracture, so as to solve the problem in the prior art that it is difficult to remove the remaining parts of the screw except the main nail for a patient with an internal fixator installed.

[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 anterior ring of pelvic fracture, comprising: a main screw, a screw barrel and a limiting mechanism;

[0008] The through hole in the nail barrel is in a stepped shape;

[0009] The nail head of the main nail is placed in the nail barrel, the nail rod of the main nail passes through the through hole, and the limiting mechanism is detachably connected in the nail barrel, and the limiting mechanism is used to limit the rotation of the main nail;

[0010] When the detachable screw for fixing the anterior ring of the pelvic fracture is removed, the limiting mechanism is separated from the through hole, and the main nail is rotated by a preset angle and then separated from the nail tube.

[0011] Optionally, the nail head and the nail rod are integrally formed;

[0012] The length of the nail head is smaller than the length of the through hole near the main nail, the length of the nail head is larger than the width of the through hole near the main nail, and the width of the nail head is smaller than the width of the through hole near the main nail;

[0013] When the limiting mechanism limits the rotation of the main nail, the nail head forms a preset angle with the end of the through hole close to the main nail in the nail tube.

[0014] Optionally, the limiting mechanism includes a supporting portion and a limiting portion;

[0015] Both sides of the support portion are respectively formed integrally with the limiting portion, and one end of the limiting portion away from the support portion is in a stepped shape.

[0016] Optionally, the thread on the nail rod includes a coarse thread and a fine thread, the coarse thread is close to the nail head, and the fine thread is far away from the nail head.

[0017] Optionally, a cavity is provided inside the main nail, and the cavity passes through the main nail.

[0018] Optionally, a side wall of an end of the nail rod away from the nail head is provided with a plurality of injection holes, and the injection holes are communicated with the cavity.

[0019] Optionally, the removable screw for fixing anterior ring of pelvic fracture further comprises an inner screw;

[0020] The inner wall of the nail barrel is provided with a clamping thread, and the inner screw is connected to the nail barrel through the clamping thread, so that the limiting mechanism is clamped between the inner screw and the main nail.

[0021] A second aspect of the present invention provides an internal fixation device, comprising a connecting cross bar and at least two detachable screws for fixing an anterior ring of a pelvic fracture according to any one of the first aspects above, wherein the detachable screws for fixing an anterior ring of a pelvic fracture are connected by the connecting cross bar.

[0022] Optionally, 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.

[0023] Optionally, a limiting groove is provided on the end surface of the limiting mechanism away from the main nail, and the connecting cross bar matches the limiting groove.

[0024] The technical solution of the present invention has the following advantages:

[0025] The present invention provides a detachable screw for fixing anterior ring of pelvic fracture and an internal fixation device, which solves the problem in the prior art that it is difficult to remove the remaining parts of the screw except the main screw for patients with internal fixation frames. When the main screw does not need to be removed, the remaining parts of the detachable screw for fixing anterior ring of pelvic fracture can be removed, thereby reducing the discomfort of the patient after surgery. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of the structure of a detachable screw for fixing the anterior ring of a pelvic fracture according to the present invention;

[0028] Figure 2 is a schematic structural diagram of a main nail according to the present invention;

[0029] Figure 3 is a schematic structural diagram of a nail barrel according to the present invention;

[0030] Figure 4 is a schematic structural diagram of a limiting mechanism according to the present invention;

[0031] Figure 5 Schematic diagram of the structure of the internal fixation device according to the present invention.

[0032] In the figure,

[0033] 1. Main nail; 2. Nail tube; 3. Limiting mechanism; 4. Inner screw; 5. Connecting cross bar; 11. Nail head; 12. Nail rod; 13. Coarse thread; 14. Fine thread; 15. Cavity; 16. Injection hole; 21. Through hole; 22. Pressing thread; 23 Slot; 31. Support part; 32. Limiting part; 33. Limiting groove. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are 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, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0036] In the present invention, the word "exemplary" is used to mean "used as an example, illustration or description". Any embodiment described as "exemplary" in the present invention is not necessarily to be construed as being preferred or advantageous over other embodiments. The following description is given to enable any technician in the field 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 will not be elaborated 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 in the present invention.

[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 anterior ring of pelvic fracture, which can be used for postoperative fixation of anterior pelvic ring injury, for example, postoperative fixation of symphysis pubis separation and postoperative fixation of pubic ramus fracture. Figure 1 is a schematic diagram of the structure of a detachable screw for fixing the anterior ring of a pelvic fracture according to the present invention, Figure 3 Schematic diagram of the structure of the nail barrel according to the present invention. Figure 1 and Figure 3 As shown, the detachable screw for fixing anterior ring of pelvic fracture comprises: a main nail 1, a nail tube 2 and a limiting mechanism 3. Specifically, the main nail 1, the nail tube 2 and the limiting mechanism 3 are connected to form a detachable screw for fixing anterior ring of pelvic fracture, and the detachable screw for fixing anterior ring of pelvic fracture is placed at the pelvic fracture site, so that the fracture site can be effectively fixed.

[0039] The through hole 21 in the nail tube 2 is stepped; the nail head 11 of the main nail 1 is placed in the nail tube 2, the nail rod 12 of the main nail 1 passes through the through hole 21, and the limiting mechanism 3 is detachably connected in the nail tube 2, and the limiting mechanism 3 is used to limit the rotation of the main nail 1. Specifically, the main nail 1, the nail tube 2 and the limiting mechanism 3 are connected to form a detachable screw for fixing the anterior ring of the pelvic fracture, and then the detachable screw for fixing the anterior ring of the pelvic fracture is inserted into the pelvic fracture. The nail tube 2 and the limiting mechanism 3 can be removed while retaining the main nail 1, thereby reducing the patient's discomfort without affecting the patient's recovery. In addition, the end of the through hole 21 close to the main nail 1 can be rectangular or elliptical, etc. Those skilled in the art should know that the shape of the end of the through hole 21 close to the main nail 1 is not used to limit the present invention, and other shapes are also within the scope of protection of the present invention, for example, rhombus.

[0040] When the detachable screw for fixing the anterior ring of the pelvic fracture is removed, the limiting mechanism 3 is disengaged from the through hole 21, and the main nail 1 is rotated by a preset angle and then disengaged from the nail tube 2. Specifically, the preset angle is the angle between the nail head 11 of the main nail 1 and the end of the through hole 21 close to the main nail 1 when the detachable screw for fixing the anterior ring of the pelvic fracture is formed. When it is necessary to keep the main nail 1 at the pelvic fracture and remove the rest of the detachable screw for fixing the anterior ring of the pelvic fracture, first, remove the limiting mechanism 3 from the through hole 21; then, rotate the main nail 1 so that the nail head 11 is parallel to the end of the through hole 21 close to the main nail 1, and the nail tube 2 moves in a direction away from the nail rod, and the nail head moves outside the through hole 21, thereby separating the nail tube 2 from the main nail 1; finally, remove the nail tube 2.

[0041] The screws used for pelvic fractures in the prior art do not have a detachable function, and usually adopt a method of integrally forming the main nail 1 and the nail tube 2. However, the screws formed in this way cannot be used in partial fractures. In this embodiment, a detachable screw for fixing the anterior ring of pelvic fractures is designed, which is different from the prior art. The nail tube 2 and the limiting mechanism 3 can be removed while retaining the main nail 1. This embodiment solves the problem in the prior art that it is difficult to remove the rest of the main nail 1 for patients with internal fixation frames, thereby reducing the discomfort of patients after surgery.

[0042] In some optional embodiments, such as Figure 2 As shown, the nail head 11 and the nail rod 12 are integrally formed. The nail head 11 and the nail rod 12 together constitute the main nail 1. The integral formation of the nail head 11 and the nail rod 12 increases the strength of the main nail 1, making the main nail 1 not easily damaged.

[0043] The length of the nail head 11 is smaller than the length of the end of the through hole 21 close to the main nail 1 (i.e., the smaller hole in the stepped hole), the length of the nail head 11 is larger than the width of the end of the through hole 21 close to the main nail 1 (i.e., the smaller hole in the stepped hole), and the width of the nail head 11 is smaller than the width of the end of the through hole 21 close to the main nail 1; when the limiting mechanism 3 restricts the rotation of the main nail 1, the nail head 11 forms a preset angle with the end of the through hole 21 close to the main nail 1 in the nail tube 2. Specifically, in order to allow the nail head 11 to pass through the end of the through hole 21 close to the main nail 1, the length and width of the nail head 11 are smaller than the length and width of the end of the through hole 21 close to the main nail 1; in order to prevent the nail head 11 from passing through the end of the through hole 21 close to the main nail 1 after the main nail 1 is rotated to a certain angle, the length of the nail head 11 is larger than the width of the end of the through hole 21 close to the main nail 1 (i.e., the smaller hole in the stepped hole). Therefore, when the main nail 1, the nail tube 2 and the limiting mechanism 3 form a detachable screw for fixing the anterior ring of the pelvic fracture, first, the main nail 1 is rotated so that the nail head 11 of the main nail 1 can pass through the through hole 21 close to one end of the main nail 1, and then, the nail head 11 passes through the through hole 21 close to one end of the main nail 1 and enters the nail tube 2. Secondly, the main nail 1 is rotated so that the nail head 11 will not detach from the through hole 21 close to one end of the main nail 1, and matches with the limiting mechanism 3. Finally, the limiting mechanism 3 is inserted into the through hole 21 close to one end of the main nail 1, thereby squeezing the main nail 1 so that the main nail 1 cannot rotate, thereby preventing the nail head 11 from detaching from the nail tube 2.

[0044] To illustrate the limiting mechanism 3, in some optional embodiments, such as Figure 4 As shown, the limiting mechanism 3 includes a supporting portion 31 and a limiting portion 32; the two sides of the supporting portion 31 are respectively integrally formed with the limiting portion 32, and the end of the limiting portion 32 away from the supporting portion 31 is in a stepped shape. Specifically, when the main nail 1 is restricted from rotating by the limiting mechanism 3, the limiting portion 32 is inserted into the end of the through hole 21 close to the main nail 1, and because the end of the limiting portion 32 away from the supporting portion 31 is in a stepped shape, it can be well matched with the stepped through hole 21, and then when the limiting portion 32 is inserted into the end of the through hole 21 close to the main nail 1, it can firmly squeeze the main nail 1 to prevent the main nail 1 from rotating out of the nail barrel 2.

[0045] To illustrate the threads on the nail rod 12, in some optional embodiments, the threads on the nail rod 12 include coarse threads 13 and fine threads 14, the coarse threads 13 are close to the nail head 11, and the fine threads 14 are far away from the nail head 11. Specifically, the coarse threads 13 have high strength and good fixing performance; the fine threads 14 have good sealing performance. Under the premise of not taking anti-loosening measures, the anti-loosening performance of the fine threads 14 is better than that of the coarse threads 13, but the strength of the fine threads 14 is low. Therefore, setting the threads on the nail rod 12 as coarse threads 13 and fine threads 14 can effectively enhance the holding force of the main nail 1.

[0046] In other embodiments, the middle of the nail rod 12 may be provided with a coarse thread 13, and both ends of the nail rod 12 may be provided with fine threads 14. By alternately providing the coarse thread 13 and the fine thread 14 on the nail rod 12, the holding force of the nail rod 12 is further enhanced, and the pelvic fracture can be effectively fixed.

[0047] In some optional embodiments, a cavity 15 is provided inside the main nail 1, and the cavity 15 passes through the main nail 1. The cavity 15 is provided inside the main nail 11, so that after the detachable screw for fixing the anterior ring of the pelvic fracture is inserted, the pressure in the bone of the pelvic fracture can be released through the cavity 15, which is conducive to the recovery of the pelvic fracture. In addition, the detachable screw for fixing the anterior ring of the pelvic fracture is guided through the cavity 15 by a Kirschner wire, so that the fracture can be accurately fixed. When guiding with the Kirschner wire, a Kirschner wire is first inserted into the fracture, and then the main nail 1 and the nail tube 2 are passed through the Kirschner wire, and then the detachable screw for fixing the anterior ring of the pelvic fracture is inserted into the position where the Kirschner wire is located, and finally the Kirschner wire is withdrawn. At the same time, fillers can also be filled in the cavity 15 to improve the performance of the main nail 1 and help the recovery of the fracture.

[0048] To further explain the nail rod 12, in some optional embodiments, the side wall of the nail rod 12 away from the nail head 11 is provided with a plurality of injection holes 16, and the injection holes 16 are connected to the cavity 15. After the main nail 1 is inserted into the pelvic fracture, bone cement can be injected into the cavity 15 from the nail head 11, and the bone cement can enter the pelvic fracture through the injection holes 16, which is beneficial to the recovery of the pelvic fracture. At the same time, since the elderly usually suffer from osteoporosis, the degree of bone damage is relatively serious when a fracture occurs. Inserting bone cement in the cavity 15 can improve the mechanical strength of the main nail 1, which is beneficial to the postoperative rehabilitation of the fracture.

[0049] In some optional embodiments, the detachable screw for fixing the anterior ring of pelvic fracture further includes an inner screw 4; the inner wall of the nail tube 2 is provided with a compression thread 22, and the inner screw 4 is connected to the nail tube 2 through the compression thread 22, and the limiting mechanism 3 is compressed between the inner screw 4 and the main nail 1. Specifically, after the main nail 1, the nail tube 2 and the limiting mechanism 3 are connected to form the detachable screw for fixing the anterior ring of pelvic fracture, in order to prevent the limiting mechanism 3 from being separated from the through hole 21, causing the main nail 1 to be separated from the nail tube 2, the limiting mechanism 3 is firmly restricted in the through hole 21 through the action of the inner screw 4 and the nail tube 2, ensuring that the main nail 1 will not be separated from the nail tube 2 by itself. In addition, when the internal fixation device is formed by the detachable screw for fixing the anterior ring of pelvic fracture, the inner screw 4 can also be used to compress the connecting cross bar 5 between the inner screw 4 and the limiting mechanism 3.

[0050] This embodiment also provides an internal fixation device, such as Figure 5As shown, it includes a connecting cross bar 5 and at least two detachable screws for fixing anterior ring of pelvic fracture according to the above embodiment, and the detachable screws for fixing anterior ring of pelvic fracture are connected by the connecting cross bar 5. The connecting cross bar 5 is used to connect multiple detachable screws for fixing anterior ring of pelvic fracture to form an internal fixation device, which can play a good role in fixing the fractured bones.

[0051] In some optional embodiments, two opposite slots 23 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 23. Specifically, when a plurality of pelvic fracture anterior ring fixing detachable screws are connected by the connecting cross bar 5 to form an internal fixation device, the connecting cross bar 5 can be inserted into the slots 23, and then the connecting cross bar 5 is pressed between the inner screw 4 and the limiting mechanism 3 by the inner screw 4, and the connecting cross bar 5 can extend through the slots 23.

[0052] To further explain the limiting mechanism 3, in some optional embodiments, a limiting groove 33 is provided on the end surface of the limiting mechanism 3 away from the main nail 1, and the connecting cross bar 5 matches the limiting groove 33. Since the limiting groove 33 matching the connecting cross bar 5 is provided on the limiting mechanism 3, the connecting cross bar 5 can be well fixed. At the same time, the limiting mechanism 3 can also prevent the connecting cross bar 5 from being damaged when the inner screw 4 is screwed in and pressurized.

[0053] Although the embodiments of the present invention have been described in conjunction with 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, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A detachable screw for fixing the anterior ring of a pelvic fracture, characterized in that: include: A main nail (1), a nail tube (2) and a limiting mechanism (3); The through hole (21) in the nail barrel (2) is in a stepped shape, and the end of the through hole (21) close to the main nail (1) is rectangular, elliptical or diamond-shaped; The limiting mechanism (3) comprises a supporting portion (31) and a limiting portion (32); Both sides of the support portion (31) are respectively integrally formed with the limiting portion (32), and one end of the limiting portion (32) away from the support portion (31) is in a stepped shape; The nail head (11) of the main nail (1) is placed in the nail tube (2), the nail rod (12) of the main nail (1) passes through the through hole (21), and the limiting mechanism (3) is detachably connected in the nail tube (2). The limiting mechanism (3) is used to limit the rotation of the main nail (1). The length of the nail head (11) is smaller than the length of the through hole (21) at one end close to the main nail (1), the length of the nail head (11) is larger than the width of the through hole (21) at one end close to the main nail (1), and the width of the nail head (11) is smaller than the width of the through hole (21) at one end close to the main nail (1); When the limiting mechanism (3) limits the rotation of the main nail (1), the nail head (11) in the nail barrel (2) forms a preset angle with the end of the through hole (21) close to the main nail (1); When the detachable screw for fixing the anterior ring of a pelvic fracture is removed, the limiting mechanism (3) is disengaged from the through hole (21), and the main nail (1) is rotated at a preset angle and then disengaged from the nail tube (2).

2. The detachable screw for fixing the anterior ring of pelvic fracture according to claim 1, characterized in that: The nail head (11) and the nail rod (12) are integrally formed.

3. The detachable screw for fixing the anterior ring of pelvic fracture according to claim 1, characterized in that: The threads on the nail rod (12) include a coarse thread (13) and a fine thread (14), wherein the coarse thread (13) is close to the nail head (11) and the fine thread (14) is far from the nail head (11).

4. The detachable screw for fixing the anterior ring of pelvic fracture according to claim 1, characterized in that: A cavity (15) is provided inside the main nail (1), and the cavity (15) passes through the main nail (1).

5. The detachable screw for fixing the anterior ring of pelvic fracture according to claim 4, characterized in that: A plurality of injection holes (16) are provided on a side wall of one end of the nail rod (12) away from the nail head (11), and the injection holes (16) are in communication with the cavity (15).

6. The detachable screw for fixing the anterior ring of pelvic fracture according to claim 1, characterized in that: Also includes an inner screw (4); The inner wall of the nail barrel (2) is provided with a clamping thread (22), and the inner screw (4) is connected to the nail barrel (2) via the clamping thread (22), so that the limiting mechanism (3) is clamped between the inner screw (4) and the main nail (1).

7. An internal fixation device, characterized in that: It comprises a connecting cross bar (5) and at least two detachable screws for fixing anterior ring of pelvic fracture according to any one of claims 1 to 6, wherein the detachable screws for fixing anterior ring of pelvic fracture are connected via the connecting cross bar (5).

8. The internal fixation device according to claim 7, characterized in that: Two opposing slots (23) 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 (23).

9. The internal fixation device according to claim 7 or 8, characterized in that: A limiting groove (33) is provided on the end surface of the limiting mechanism (3) away from the main nail (1), and the connecting cross bar (5) matches the limiting groove (33).

Images