A pelvic fracture anterior ring fixing screw and internal fixation device

Abstract

The present invention provides a pelvic fracture anterior ring fixing screw, which relates to the technical field of orthopedic medical devices. The pelvic fracture anterior ring fixing screw comprises a screw seat tube, a screw and a limiting mechanism; the screw is arranged in the screw seat tube, and the front end of the screw extends out of the front port of the screw seat tube; the limiting mechanism is arranged in the cylinder cavity of the screw seat tube, and when the limiting mechanism presents a first state, the head of the screw is restricted in the screw seat tube, and when the limiting mechanism presents a second state, the screw can be separated from the screw seat tube as a whole. The pelvic fracture anterior ring fixing screw of the present invention realizes the combination and disassembly of the screw seat tube and the screw by setting a limiting mechanism, which facilitates the removal of the connecting rod and the screw seat tube while retaining the screw. On this basis, the present invention also provides an internal fixation device.

Description

Technical Field

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

[0002] Minimally invasive percutaneous anterior pelvic ring internal fixator (MINI) is currently used in the clinic to treat brittle anterior pelvic ring injuries in the elderly. The most widely used and effective device in this procedure is called an internal fixator (INFIX).

[0003] The original intention of the internal fixator is to stabilize the anterior pelvic ring, so the anterior pelvic ring injury, including pubic symphysis separation and pubic ramus fracture, is its best indication. Because the internal fixator is located in the lower abdomen and in front of the pelvis, thin patients will experience subjective discomfort, especially in the 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 surgery should be performed to remove the internal fixator.

[0004] However, in the early stage after the rehabilitation surgery of the anterior pelvic ring injury, the pelvis is not fully recovered and the screw itself is not convenient to remove. How to remove the rest of the pedicle screw while retaining the screw or the screw rod has become an urgent problem to be solved in the clinical medical community. Summary of the invention

[0005] The purpose of the present invention is to provide a pelvic fracture anterior ring fixing screw, which helps to solve the above technical problems.

[0006] The present invention is achieved in that:

[0007] A screw for fixing anterior ring of pelvic fracture, comprising a screw seat tube, a screw and a limiting mechanism; the screw is arranged in the screw seat tube, and the front end of the screw extends out of the front end of the screw seat tube; the limiting mechanism is arranged in the tube cavity of the screw seat tube, when the limiting mechanism is in a first state, the head of the screw is restricted in the screw seat tube, and when the limiting mechanism is in a second state, the screw can be completely separated from the screw seat tube.

[0008] During the operation of the above-mentioned pelvic fracture anterior ring fixing screw, the limiting mechanism is first positioned in the first state, and the screw is tightened and fixed to the part of the pelvis to be repaired. Then, multiple screw seat tubes are connected and fixed through a connecting rod. In the early stage of rehabilitation after the operation, when the pelvic fixation effect is obvious and subjective discomfort gradually appears, the connecting rod and each screw seat tube are removed in turn through a minimally invasive method, while retaining the screw. Among them, when removing the screw seat tube, the limiting mechanism is moved to the position in the second state, and the screw seat tube can be smoothly removed from the rear end of the screw.

[0009] Further, the limiting mechanism includes a U-shaped collar and a pin; a guide groove is provided on the nail seat tube, and the extension direction of the guide groove is perpendicular to the axis of the nail seat tube; the U-shaped collar is located in the guide groove, and when the limiting mechanism presents a first state, the U-shaped collar is clamped outside the screw; when the limiting mechanism presents a second state, the U-shaped collar is separated from the screw; the pin is provided on the nail seat tube to limit the U-shaped collar from being separated from the screw. Its technical effect is that: the open end of the U-shaped collar is used to clamp the screw, and the distance between the two clamping arms of the U-shaped collar is greater than the diameter of the screw on the screw and smaller than the radial size of the head of the screw. In the first state, the screw is inserted into the nail seat tube, and its screw can extend from the U-shaped collar, while the head of the screw is restricted by the U-shaped collar and cannot extend. In the second state, the U-shaped collar no longer restricts the head of the screw, so the entire screw can be removed from the nail seat tube, that is, the nail seat tube can be separated from the screw. Additionally, the pin can position the U-shaped collar in the first state.

[0010] Furthermore, a limiting protrusion is provided at the open end of the U-shaped collar, and the extending direction of the limiting protrusion is perpendicular to the extending direction of the guide groove; the limiting protrusion is used to limit the U-shaped collar from being separated from the nail seat tube. Its technical effect is that since the U-shaped collar is around the human pelvis during the whole operation, the U-shaped collar and the nail seat tube are movably connected, which can prevent the U-shaped collar from falling off and falling into the human body during the operation, avoiding safety hazards.

[0011] Furthermore, the pin is a plug; the length direction of the plug is parallel to the axis of the nail seat tube, and the U-shaped collar is provided with a pin hole that matches the plug. The technical effect is that since the U-shaped collar moves along the guide groove, and the extension direction of the guide groove is perpendicular to the axis of the nail seat tube, the pin whose length direction is parallel to the axis of the nail seat tube is also perpendicular to the moving direction of the U-shaped collar. After the pin is inserted into the pin hole, the U-shaped collar can be limited to the position of the clamping screw.

[0012] Furthermore, the pin is a spring latch, which can be inserted into the pin hole under the action of its own elastic force. The technical effect is that the size of the pin is very small in the entire pelvic fracture anterior ring fixing screw structure. When the pin is designed as a spring latch, regardless of whether the pin has a locking effect, it will not be separated from the screw seat tube, that is, it is not easy to fall into the human body muscle, will not cause surgical accidents, and will not bring safety hazards. In addition, the spring latch is very easy to operate during the locking and unlocking process.

[0013] Furthermore, the pin is threadedly connected to the nail seat tube; the length direction of the pin is parallel to the axis of the nail seat tube, and the end of the pin can contact the U-shaped clamping ring. The technical effect is that at this time, the U-shaped clamping ring is tightly pressed by the end of the pin to achieve the fixation of the U-shaped clamping ring. The structure of the threaded connection between the pin and the nail seat tube also makes it difficult for the pin to disengage from the nail seat tube, thereby improving the safety of the operation, and the locking can be completed by simply screwing the pin so that the pin abuts and tightly presses the U-shaped clamping ring.

[0014] Furthermore, the pin is threadedly connected to the nail seat tube; the length direction of the pin is parallel to the axis of the nail seat tube, and the U-shaped clamp is provided with a screw hole, and the screw hole is threadedly connected to the pin. The technical effect is that similar to the above structure, the pin threadedly connected to the nail seat tube also improves the safety of the operation. At this time, since the screw hole is provided on the U-shaped clamp, the locking effect of the pin on the U-shaped clamp is more reliable.

[0015] Furthermore, a receiving cavity is provided in the screw, and a through hole is provided on the side wall of the screw. The technical effect is that the receiving cavity is used to insert bone cement, and the through hole is used to inject bone cement into the receiving cavity. Pelvic fractures in elderly patients are often accompanied by osteoporosis, so the degree of comminution is often more serious. Inserting bone cement in the screw can greatly improve the mechanical strength of the screw, which is beneficial to the postoperative rehabilitation of fractures.

[0016] An internal fixation device comprises a connecting rod and at least two of the above-mentioned pelvic fracture anterior ring fixing screws, wherein the screw seat tubes are fixedly connected by the connecting rod.

[0017] Furthermore, a clamping nut and a gasket are also provided on the nail seat tube; an internal thread is provided on the inner wall of the nail seat tube, and the clamping nut is threadedly connected to the nail seat tube through the internal thread, and the clamping nut, the connecting rod, the gasket and the screw are sequentially arranged on the nail seat tube. The technical effect is that the clamping nut is used to clamp and fix the connecting rod in the nail seat tube, and the gasket is located between the connecting rod and the head of the screw, which plays a role in reducing friction and buffering collision, and preventing wear on the screw-in groove on the connecting rod or the screw head. In addition, the screw should be set as a ball head screw, and the inner cavity of the corresponding nail seat tube is also set as a spherical chamber. The screw forms a universal screw, which can be inserted into the pelvis in a larger angle range.

[0018] The beneficial effects of the present invention are:

[0019] The anterior ring fixing screw and internal fixation device for pelvic fracture of the present invention realizes the combination and disassembly of the screw seat tube and the screw by setting a limiting mechanism, and facilitates the removal of the connecting rod and the screw seat tube while retaining the screw. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 A schematic structural diagram of a pelvic fracture anterior ring fixing screw provided by the first embodiment of the present invention;

[0022] Figure 2 A cross-sectional view of the connection between the screw seat tube and the U-shaped collar in the anterior ring fixation screw for pelvic fractures provided by the second embodiment of the present invention;

[0023] Figure 3 A schematic diagram of the internal structure of the connection between the screw seat tube and the U-shaped collar of a pelvic fracture anterior ring fixation screw provided in the third embodiment of the present invention;

[0024] Figure 4 A schematic diagram of the internal structure of the connection between the screw seat tube and the U-shaped collar of a pelvic fracture anterior ring fixation screw provided in the fourth embodiment of the present invention;

[0025] Figure 5 A schematic diagram of the internal structure of the connection between the screw seat tube and the U-shaped collar of a pelvic fracture anterior ring fixation screw provided in the fifth embodiment of the present invention;

[0026] Figure 6 A schematic structural diagram of an internal fixation device provided in a sixth embodiment of the present invention;

[0027] Figure 7 A schematic diagram of the installation of the internal fixation device provided by the sixth embodiment of the present invention when used in a human body (before the nail seat tube and the connecting rod are removed);

[0028] Figure 8 This is a schematic diagram of the installation of the internal fixation device provided by the sixth embodiment of the present invention when used in a human body (after the nail seat tube and the connecting rod are removed).

[0029] Icons: 100-nail seat cylinder; 110-guide groove; 200-screw; 210-through hole; 300-U-shaped clamping ring; 310-limiting protrusion; 400-pin; 500-connecting rod; 600-gasket; 700-pelvis. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and marked in the drawings can be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0033] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0034] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0035] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0037] First embodiment:

[0038] Figure 1 This is a schematic diagram of the structure of the anterior ring fixation screw for pelvic fracture provided by the first embodiment of the present invention. Figure 1 The present embodiment provides a pelvic fracture anterior ring fixing screw, which includes a screw seat tube 100, a screw 200 and a limiting mechanism.

[0039] Among them, the screw 200 is arranged in the nail seat tube 100, and the front end of the screw 200 extends out of the front port of the nail seat tube 100; the limiting mechanism is arranged in the cylinder cavity of the nail seat tube 100, and when the limiting mechanism is in a first state, the head of the screw 200 is restricted in the nail seat tube 100, so that the screw 200 cannot be separated from the nail seat tube 100; when the limiting mechanism is in a second state, the screw 200 can pass through the front port of the nail seat tube 100 as a whole and separate from the nail seat tube 100.

[0040] Furthermore, if Figure 1 As shown, the limiting mechanism includes a U-shaped collar 300 and a pin 400. A guide groove 110 is provided on the nail seat tube 100, and the extension direction of the guide groove 110 is perpendicular to the axis of the nail seat tube 100; the U-shaped collar 300 is located in the guide groove 110, and when the limiting mechanism is in the first state, the U-shaped collar 300 is clamped outside the screw 200; when the limiting mechanism is in the second state, the U-shaped collar 300 is separated from the screw 200; the pin 400 is provided on the nail seat tube 100, and is used to limit the U-shaped collar 300 from being separated from the screw 200.

[0041] In the above structure, the limiting mechanism can also be configured as a U-shaped spring clip, a snap-on fixing clip or even directly replaced by a screw.

[0042] It should be emphasized that the outer layer of the screw 200 should be coated with a hydroxyapatite coating, which has good biocompatibility and bone conduction properties, and also has extremely low absorption rate and degradation rate. It has been observed that after the screw 200 is coated with hydroxyapatite material, it exhibits good biomechanical, histological and histomorphological effects in clinical surgery. Its superior fixation performance and good long-term stability also greatly reduce the nail tract infection rate.

[0043] The use of the anterior ring fixation screw for pelvic fracture in this embodiment is as follows:

[0044] First, the limiting mechanism is positioned in the first state, and the screw 200 is tightened and fixed to the part of the pelvis 700 to be repaired. Then, multiple screw base tubes 100 are connected and fixed through the connecting rod 500. In the early stage of postoperative rehabilitation, when the fixation effect of the pelvis 700 is obvious and subjective discomfort gradually appears, the connecting rod 500 and each screw base tube 100 are removed in turn by a minimally invasive method, and the screw 200 is retained. When removing the screw base tube 100, the limiting mechanism is moved to the second state, and the screw base tube 100 can be smoothly removed from the rear end of the screw 200.

[0045] Second embodiment:

[0046] Figure 2 This is a cross-sectional view of the connection between the screw seat tube 100 and the U-shaped collar 300 of the pelvic fracture anterior ring fixing screw provided by the second embodiment of the present invention. Figure 2 The present embodiment provides a pelvic fracture anterior ring fixing screw, which is substantially the same as the pelvic fracture anterior ring fixing screw of the first embodiment. The difference between the two is that a limiting protrusion 310 is provided at the open end of the U-shaped clamping ring 300 in the pelvic fracture anterior ring fixing screw of the present embodiment, and the extension direction of the limiting protrusion 310 is perpendicular to the extension direction of the guide groove 110; the limiting protrusion 310 is used to limit the U-shaped clamping ring 300 from detaching from the screw seat tube 100. Figure 2 The direction of the arrow in FIG. 1 is the direction in which the U-shaped collar 300 is inserted into the guide groove 110 .

[0047] The limiting protrusion 310 of one clamping arm of the U-shaped clamping ring 300 should extend in a direction away from the other clamping arm to avoid interference with the screw 200 during movement.

[0048] Third embodiment:

[0049] Figure 3 This is a schematic diagram of the internal structure of the connection between the screw seat tube 100 and the U-shaped collar 300 of the pelvic fracture anterior ring fixing screw provided by the third embodiment of the present invention. Figure 3The present embodiment provides a pelvic fracture anterior ring fixing screw, which is substantially the same as the pelvic fracture anterior ring fixing screw of the first embodiment or the second embodiment. The difference between the two is that the pin 400 in the pelvic fracture anterior ring fixing screw of the present embodiment is a plug; the length direction of the plug is parallel to the axis of the screw seat tube 100, and a pin hole cooperating with the plug is provided on the U-shaped clamping ring 300.

[0050] Furthermore, if Figure 3 As shown, the pin 400 is a spring pin, which can be inserted into the pin hole under its own elastic force. The spring pin accumulates elastic potential energy when it is pulled out of the U-shaped collar 300, and can be reinserted into the pin hole of the U-shaped collar 300 under the elastic force after being released. Figure 3 The direction of the arrow in the figure is the direction of movement of the spring latch when in use.

[0051] Fourth embodiment:

[0052] Figure 4 This is a schematic diagram of the internal structure of the connection between the screw seat tube 100 and the U-shaped collar 300 of the anterior ring fixation screw for pelvic fracture provided by the fourth embodiment of the present invention. Figure 4 This embodiment provides a pelvic fracture anterior ring fixing screw, which is substantially the same as any one of the pelvic fracture anterior ring fixing screws in the first to third embodiments, and the difference between the two is that the pin 400 in the pelvic fracture anterior ring fixing screw of this embodiment is threadedly connected with the screw base tube 100; the length direction of the pin 400 is parallel to the axis of the screw base tube 100, and the end of the pin 400 can contact the U-shaped clamping ring 300. The U-shaped clamping ring 300 can be fixed at a desired position by the threaded connection relationship of the pin 400.

[0053] Fifth embodiment:

[0054] Figure 5 This is a schematic diagram of the internal structure of the connection between the screw seat tube 100 and the U-shaped collar 300 of the anterior ring fixation screw for pelvic fractures provided in the fifth embodiment of the present invention. Figure 5 The present embodiment provides a pelvic fracture anterior ring fixing screw, which is substantially the same as any one of the pelvic fracture anterior ring fixing screws in the first to third embodiments. The difference between the two is that the pin 400 in the pelvic fracture anterior ring fixing screw in the present embodiment is threadedly connected to the screw seat tube 100; the length direction of the pin 400 is parallel to the axis of the screw seat tube 100, and a screw hole is provided on the U-shaped clamping ring 300, which is threadedly connected to the pin 400.

[0055] It should be noted that, in the above five embodiments, after the screw 200 is fixed, the top end of the pin 400 should be located below the bottom surface of the U-shaped groove of the nail seat tube 100 to avoid affecting the installation stability of the connecting rod 500.

[0056] Furthermore, if Figure 5 As shown, on the basis of any of the above embodiments, a receiving cavity is provided in the screw 200, and a through hole 210 is provided on the side wall of the screw 200. The receiving cavity is used to insert bone cement, and the through hole 210 is used to inject bone cement into the receiving cavity. Pelvic fractures 700 in elderly patients are often accompanied by osteoporosis, so the degree of comminution is often more serious. Inserting bone cement in the screw 200 can greatly improve the mechanical strength of the screw 200, which is beneficial to postoperative rehabilitation of fractures.

[0057] Sixth embodiment:

[0058] Figure 6 This is a schematic diagram of the structure of an internal fixation device provided in a sixth embodiment of the present invention. Figure 7 This is a schematic diagram of the installation of the internal fixation device provided by the sixth embodiment of the present invention when used in a human body (before the nail seat tube 100 and the connecting rod 500 are removed); Figure 8 This is a schematic diagram of the installation of the internal fixation device provided by the sixth embodiment of the present invention in the human body (after the nail holder 100 and the connecting rod 500 are removed). Figure 6 , Figure 7 , Figure 8 This embodiment provides an internal fixation device, which includes a connecting rod 500 and at least two pelvic fracture anterior ring fixing screws in any of the above embodiments, and the screw seat tubes 100 are fixedly connected by the connecting rod 500.

[0059] Furthermore, if Figure 6 As shown, a clamping nut and a gasket 600 are also provided on the nail seat tube 100; an internal thread is provided on the inner wall of the nail seat tube 100, and the clamping nut is threadedly connected to the nail seat tube 100 through the internal thread. The clamping nut, connecting rod 500, gasket 600 and screw 200 are arranged on the nail seat tube 100 in sequence.

[0060] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A pelvic fracture anterior ring fixation screw, characterized in that: The invention comprises a nail seat tube (100), a screw (200) and a limiting mechanism; the screw (200) is arranged in the nail seat tube (100), and the front end of the screw (200) extends out of the front end of the nail seat tube (100); the limiting mechanism is arranged in the cylinder cavity of the nail seat tube (100); when the limiting mechanism is in a first state, the head of the screw (200) is limited in the nail seat tube (100); when the limiting mechanism is in a second state, the screw (200) can be completely separated from the nail seat tube (100); The limiting mechanism comprises a U-shaped collar (300) and a pin (400); The nail seat tube (100) is provided with a guide groove (110), and the extension direction of the guide groove (110) is perpendicular to the axis of the nail seat tube (100); the U-shaped clamping ring (300) is located in the guide groove (110), and when the limiting mechanism is in a first state, the U-shaped clamping ring (300) is clamped outside the screw (200); when the limiting mechanism is in a second state, the U-shaped clamping ring (300) is separated from the screw (200); The pin (400) is arranged on the nail seat tube (100), and the length direction of the pin (400) is parallel to the axis of the nail seat tube (100), and is used to limit the U-shaped clamping ring (300) from detaching from the screw (200).

2. The anterior ring fixation screw for pelvic fracture according to claim 1, characterized in that: A limiting protrusion (310) is provided at the open end of the U-shaped clamping ring (300), and the extending direction of the limiting protrusion (310) is perpendicular to the extending direction of the guide groove (110); the limiting protrusion (310) is used to limit the U-shaped clamping ring (300) from detaching from the nail seat tube (100).

3. The anterior ring fixation screw for pelvic fracture according to claim 1, characterized in that: The pin (400) is a plug pin; the length direction of the plug pin is parallel to the axis of the pin seat tube (100), and the U-shaped clamping ring (300) is provided with a pin hole that cooperates with the plug pin.

4. The anterior ring fixation screw for pelvic fracture according to claim 3, characterized in that: The pin (400) is a spring pin and can be inserted into the pin hole under the action of its own elastic force.

5. The anterior ring fixation screw for pelvic fracture according to claim 1, characterized in that: The pin (400) is threadedly connected to the pin seat tube (100); the end of the pin (400) is capable of contacting the U-shaped clamping ring (300).

6. The anterior ring fixation screw for pelvic fracture according to claim 1, characterized in that: The pin (400) is threadedly connected to the pin seat tube (100); the U-shaped clamping ring (300) is provided with a screw hole, and the screw hole is threadedly connected to the pin (400).

7. The anterior ring fixation screw for pelvic fracture according to claim 1, characterized in that: The screw (200) is provided with a receiving cavity therein, and a through hole (210) is provided on a side wall of the screw (200).

8. An internal fixation device, characterized in that: It comprises a connecting rod (500) and at least two pelvic fracture anterior ring fixing screws according to any one of claims 1 to 7, wherein the screw seat tubes (100) are fixedly connected via the connecting rod (500).

9. The internal fixation device according to claim 8, characterized in that: The nail seat tube (100) is also provided with a clamping nut and a gasket (600); an internal thread is provided on the inner wall of the nail seat tube (100), and the clamping nut is threadedly connected to the nail seat tube (100) via the internal thread; the clamping nut, the connecting rod (500), the gasket (600) and the screw (200) are sequentially arranged on the nail seat tube (100).

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