Shape memory absorbable rib internal fixation body capable of mechanically rotating and stretching

Abstract

The invention provides a shape memory absorbable rib internal fixing body capable of mechanically rotating and stretching, which comprises an internal fixing body, the internal fixing body is made of a biodegradable polymer shape memory composite material, the internal fixing body comprises a hollow cuboid, pyramid frames are respectively arranged at two ends of the cuboid, a mechanical stretching structure is arranged in the cuboid, and the shape memory absorbable rib internal fixing body is arranged in the cuboid. The mechanical telescopic structure comprises racks which are symmetrically arranged, and the two racks are meshed through two gears; the mechanical telescopic structure is used for retracting and fixing a gear and limiting a rack through a bullet telescopic limiting device; one pyramid frame is a fixed end, the other pyramid frame is a detachable or assembled angle opening and closing device, and the two ends of the pyramid frame are provided with shape memory function barbs which are arranged at intervals. The internal fixing body is made of a polymer composite material with a bidirectional shape memory effect, and the length of the internal fixing body is adjusted through a mechanical telescopic structure and the shape memory function of the composite material so as to adapt to human anatomical structure differences.

Description

Technical Field

[0001] The invention relates to the technical field of medical devices, and in particular to a shape-memory absorbable rib internal fixator capable of mechanical rotation and extension. Background Art

[0002] Rib fractures are the most common type of chest trauma, accounting for more than 60% of chest trauma. Currently, rib fractures are mainly treated through conservative treatment and surgical treatment. However, for patients with rib fractures with suboptimal rib alignment, such as flail chest patients without anatomical reduction, surgical internal fixation is often required.

[0003] There are many methods of surgical internal fixation for rib fractures, such as Kirschner wire fixation, steel wire, ceramic nails and rib plates, wire binding fixation, memory alloy embracing device rib fixation, absorbable rib nail internal fixation, etc. Among them, absorbable rib nail internal fixation for the treatment of rib fractures causes relatively less damage and does not require a secondary operation to remove it, so it can be widely accepted by clinical physicians.

[0004] There are many absorbable rib nails in clinical use, such as imported poly-L-lactic acid absorbable rib intramedullary nails and Gangzi (absorbable rib nail GRANDFIXTM). After the absorbable rib nail is inserted into the medullary cavity after medullary expansion during surgery, the ribs can be aligned and pulled together, and then sutures can be used to reinforce the fracture ends. The magnesium alloy absorbable rib intramedullary nail (201894668U) adopts an arc-shaped flat overall design, and is also implanted into the rib medullary cavity to fix the ribs. These devices all have anti-slip stripes or barbs, but still have the following technical defects: unreliable fixation, easy displacement, etc., and often require sutures to reinforce the fracture ends, which will not only destroy the good blood supply of the periosteum and affect the healing of the fracture, but also compress the intercostal nerves at the lower edge of the ribs, causing postoperative pain; in addition, the size and shape of these inventions are fixed, and they cannot be adjusted according to the specificity of individual anatomical structures during surgery.

[0005] In addition to the above-mentioned intramedullary fixator, there are other related patents: such as a flexible absorbable rib internal fixation device (202210542735.1), which realizes anatomical reduction after rib fracture through tensioning ropes and multiple sliding body chains and locking components on the outside, and the tensioning rope is an absorbable thread; a 3D printed absorbable rib internal fixation plate structure (202020145492.4), which uses 3D printing technology to form a biodegradable arched plate body whose inner wall surface matches the inner or outer surface shape of the rib fracture position, and then fixes the rib ends by sutures; a new type of rib internal fixation device and minimally invasive surgery (201810198373.2), which realizes effective fixation of the ribs through a fixing plate on the outside of the rib and a plug-in compression unit on it. These methods all involve wrapping the outside of the fracture. Since fixation is performed on the outside of the fracture, the following technical defects still exist: damage to periosteum blood supply, impact on fracture healing, postoperative pain, inability to make individual adjustments, etc. At the same time, wrapping the outside of the fracture will also affect the overall aesthetics due to uneven skin.

[0006] Therefore, how to design a shape-memory absorbable rib internal fixator that can mechanically rotate and retract to adjust its size, is biodegradable in the body, and can mechanically rotate and retract has become an urgent problem to be solved. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a shape memory absorbable rib internal fixator that can be mechanically rotated and retracted to solve at least one of the above technical problems.

[0008] The technical solution of the present invention is: a shape memory absorbable rib internal fixator that can be mechanically rotated and retracted, including an internal fixator axially fixed in the medullary cavity of the rib, the internal fixator adopts a biodegradable polymer shape memory composite material, the internal fixator includes a hollow cuboid, and pyramid frames are respectively arranged at both ends of the cuboid. A mechanical telescopic structure is arranged in the cuboid, and the mechanical telescopic structure includes symmetrically arranged racks, and the two racks are respectively meshed by two gears; the mechanical telescopic structure retracts and fixes the gears and limits the racks through a bullet-shaped telescopic limiting device; one pyramid frame is a fixed end, and the other pyramid frame is a movable end, and the movable end is a detachable or assembled opening and closing angle device, and both ends are provided with shape memory function barbs arranged at intervals.

[0009] The internal fixation body of the present invention is made of a polymer composite material with a bidirectional shape memory effect. Through the mechanical telescopic structure and the shape memory function of the biodegradable polymer composite material, the gear is retracted, fixed and the rack is limited in cooperation with the bullet head telescopic limit device, and the length of the internal fixation body is adjusted to adapt to the differences in human anatomical structures. When the present invention is placed in the rib medullary cavity, it can be mechanically retracted through the cooperation of the gear and the rack, reducing the separation distance of the two ends during the internal fixation operation, and avoiding secondary damage to the ribs due to excessive separation; the biodegradable polymer shape memory composite material can meet the rotation rigidity required, and when the temperature of the fixation body reaches above the phase transition temperature, the barb is unfolded and returned to the initial shape, hooking the surrounding bone marrow, so that the rib internal fixation body is not easy to slip in the medullary cavity, and the fixation is more firm, and it can be automatically degraded into harmless substances in the body, without the need for surgery again to remove or worry about foreign matter remaining in the body affecting subsequent inspections and treatments, so as to achieve individualized treatment and achieve good fixation and reduction of the fracture ends. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of the installation structure of the present invention.

[0011] Figure 2 It is a schematic diagram of the initial state structure of the present invention.

[0012] Figure 3 This is a schematic diagram of the structure of the present invention after being inserted into the bone marrow cavity and rotated and stretched.

[0013] Figure 4 It is a schematic diagram of the structure of the present invention after being inserted into the bone marrow cavity and retracted.

[0014] In the figure: 1. rib; 2. left sharp head end; 3. barb; 4. knob; 5. rack; 6. gear; 7. rack slide; 8. gear slide; 9. rack connected to narrow plate; 10. gear connected to narrow plate; 11. gear limit hole; 12. rack slide bullet head telescopic limit device; 13. metal strip; 14. gear slide limit groove; 15. gear slide bullet head telescopic limit device; 16. gear slide limit hole; 17. adjustable bottom plate; 18. angled piece; 19. rotating steel column; 20. main character; 21. corner; 22. right sharp head end. DETAILED DESCRIPTION

[0015] The present invention will be further described below in conjunction with the accompanying drawings.

[0016] See also Figure 1-4The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0017] Embodiment 1: A shape memory absorbable rib internal fixator capable of mechanical rotation and extension, referring to Figure 2 , Figure 3 , including an internal fixation body axially fixed in the medullary cavity of the rib 1, characterized in that: the internal fixation body adopts a biodegradable polymer shape memory composite material of a certain strength, the internal fixation body comprises a hollow cuboid with a rectangular cross section, pyramid frames are respectively arranged at both ends of the cuboid, a mechanical telescopic structure is arranged in the cuboid, the mechanical telescopic structure comprises symmetrically arranged racks 5, and two racks 5 are respectively meshed by two gears 6; the mechanical telescopic structure retracts and fixes the gears 6 and limits the racks 5 through a bullet-shaped telescopic limiting device; one pyramid frame is a fixed end, and the other pyramid frame is a movable end, and the movable end is a detachable or assembled opening and closing angle device, and both ends are provided with shape memory function barbs arranged at intervals. The internal fixation body of the present invention is made of a polymer composite material with a bidirectional shape memory effect, and through the mechanical telescopic structure and the shape memory function of the biodegradable polymer composite material, the gears are retracted, fixed, and the racks are limited in cooperation with the bullet-shaped telescopic limiting device, and the length of the internal fixation body is adjusted to adapt to the differences in human anatomical structures. When the present invention is inserted into the rib medullary cavity, it can be mechanically expanded and contracted through the cooperation of gears and racks, thereby reducing the separation distance of the two broken ends during internal fixation surgery and avoiding secondary damage to the ribs due to excessive separation; the biodegradable polymer shape memory composite material can meet the rotational rigidity requirements and can automatically degrade into harmless substances in the body, without the need for another surgery to remove it or worry about foreign matter remaining in the body affecting subsequent examinations and treatments, thereby achieving individualized treatment and realizing good fixation and reduction of the fracture ends.

[0018] Embodiment 2: Based on Embodiment 1, refer to Figure 1The pyramid frame at the left end of the rectangular parallelepiped includes a left sharp head end 2, which is formed by the left ends of two racks 5 extending downward and upward to intersect, and the left sharp head end 2 is a fixed end; the pyramid frame at the right end of the rectangular parallelepiped includes a right sharp head end 22, and the right sharp head end 22 is an opening and closing angle device. The present invention adopts two racks whose left ends extend downward and upward to intersect to form a left sharp head end, and the left sharp head end is a fixed end; the right sharp head end is an opening and closing angle device.

[0019] Embodiment 3: On the basis of Embodiment 2, the angle-opening and closing device comprises a detachable or assembled adjustable bottom plate 17, four angled pieces 18 and three rotating steel columns 19, adjacent angled pieces 18 are hinged by rotating steel columns 19, the top angle of the pyramid frame is the main angle 20, the angle between the two angled pieces 18 on the side of the pyramid frame and the two angled pieces 18 of the extension section is the side angle 21, and the two angled pieces 18 of the extension section are respectively connected to the adjustable bottom plate 17. The angle-opening and closing device of the present invention is formed by connecting four angled pieces and three rotating steel columns, which form two side angles and a main angle to form a right sharp head end after connection; the opening and closing device and the detachable or assembled adjustable bottom plate are used to realize longitudinal size adjustment, and the size of the main angle and the side angle is changed by rotating the steel column, so that the upper and lower angled pieces are parallel to the adjustable bottom plate, and assembled into a complete rib internal fixation body of suitable size.

[0020] Embodiment 4: Based on Embodiment 3, the adjustable bottom plate 17 is located on one side of the cuboid close to the opening and closing angle device, and groove-shaped grooves are respectively provided at both ends of the adjustable bottom plate 17. The angled piece 18 and the corresponding position of the adjustable bottom plate 17 are provided with raised edges, and the raised edges match the groove-shaped grooves. The present invention uses the raised edges of the angled piece to match the groove-shaped grooves of the adjustable bottom plate to assemble into a complete rib internal fixation body of appropriate size; the size and insertion depth of the internal fixation body can be adjusted by mechanical expansion, disassembly or assembly, and adjusting the angle of the opening and closing angle device according to the differences in human anatomical structures.

[0021] Embodiment 5, on the basis of embodiment 4, a rack rail 7 is provided at one end of the two racks 5 away from the gear 6, a gear rail 8 is provided between the two gears 6, and the gear rail 8 and the two rack rails 7 are connected to the adjustable bottom plate 17; the width of the adjustable bottom plate 17 is smaller than the average size of the inner diameter of the medullary cavity of the rib 1. The width of the adjustable bottom plate used in the present invention is slightly smaller than the average size of the inner diameter of the medullary cavity of the rib, and can be adjusted by disassembly or assembly.

[0022] Embodiment 6: Based on Embodiment 5, the bullet-shaped telescopic limiting device comprises a rack slide bullet-shaped telescopic limiting device 12 and a gear slide bullet-shaped telescopic limiting device 15, and the rack slide bullet-shaped telescopic limiting device 12 is located on the rack slide 7. The present invention uses the bullet-shaped telescopic limiting device to retract and fix the gear and limit the rack. With the transmission movement of the rack, the rack slide bullet-shaped telescopic limiting device pops out from the compressed state.

[0023] Embodiment 7, on the basis of embodiment 6, a gear connecting narrow plate 10 is arranged between the two gears 6, the middle part of the gear connecting narrow plate 10 is connected to the metal strip 13 through the knob 4, and the gear slide rail bullet head telescopic limit device 15 is located at the end of the metal strip 13 away from the knob 4. The two gears of the present invention are connected by the gear connecting narrow plate, a metal strip extends from the middle of the gear connecting narrow plate, and a gear slide rail bullet head telescopic limit device is provided at the end of the metal strip.

[0024] Embodiment 8. On the basis of Embodiment 7, the gear rail 8 is provided with a gear rail limiting groove 14 close to one end of the gear 6 and a gear rail limiting hole 16 away from one end of the gear 6; the gear rail bullet-shaped telescopic limiting device 15 is located in the gear rail limiting groove 14 in a compressed state to prevent the gear 6 from moving left and right when the gear 6 is rotated by the knob 4; the gear rail bullet-shaped telescopic limiting device 15 pops out after encountering the gear rail limiting hole 16 and is stuck in the gear rail limiting hole 16 to achieve the retraction and fixation of the gear 6, and the popped-out rack rail bullet-shaped telescopic limiting device 12 blocks the rack 5 from continuing to retract or fall out of the bone marrow cavity, thereby limiting the rack 5 and meeting the reset standard. When the present invention is in the initial state, the bullet-shaped telescopic limit device of the gear slide rail is located in the limiting groove of the gear slide rail and is in a compressed state, so as to prevent the gear from moving left and right when the gear is rotated; with the transmission movement of the rack, the bullet-shaped telescopic limit device of the rack slide rail pops out from the compressed state, and when the rib internal fixation body reaches the ideal insertion depth, the left sharp head end of the mechanical telescopic device is pushed toward the right sharp head end of the opening and closing angle device for a distance approximately equal to the radius of the gear, and the bullet-shaped telescopic limit device of the rack slide rail blocks the rack from continuing to retract or coming out of the medullary cavity, and the bullet-shaped telescopic limit device of the gear slide rail pops out after encountering the limiting hole of the gear slide rail, and is stuck in the limiting hole of the gear slide rail, so as to realize the retraction and fixation of the gear and the limiting of the rack, and reach the reset standard.

[0025] Embodiment 9, on the basis of embodiment 7, the two rack rails 7 are further provided with a rack connecting narrow plate 9 at one end close to the adjustable bottom plate 17, and the rack connecting narrow plate 9 is provided with gear limiting holes 11 arranged at intervals, and the two gears 6 can be stuck in the gear limiting holes 11. The present invention adopts a rotating gear to transmit the rack forward, and the left sharp head end is placed into the medullary cavity. With the transmission movement of the rack, the rack rail bullet head telescopic limiting device pops out from the compressed state, and when the transmission distance reaches the maximum, the gear is stuck in the gear limiting hole.

[0026] Embodiment 10: Based on the embodiment 1, the pyramidal surface of the pyramid frame is provided with barbs 3 arranged at intervals. The barbs on the left and right sharp head ends of the present invention are made of a biodegradable polymer shape memory composite material of a certain strength, and are in a folded state before surgery, flatly attached to the outer surface of the internal fixation body. After being inserted into the ribs, the barbs extend out of the outer surface of the internal fixation body under the restoring force of the shape memory effect, making the fixation more secure.

[0027] During specific implementation, the rack 5 is retracted in the adjustable base plate 17 before the operation. The width of the adjustable base plate 17 and the angle of the opening and closing angle device are adjusted according to the size of the medullary cavity of the patient's broken bone. Then, the angle piece 18 and the adjustable base plate 17 are connected to form a complete rib internal fixation body.

[0028] During the operation, the right sharp head 22 of the debugged rib internal fixator is first placed into the medullary cavity of the first fracture end, and then the exposed left sharp head is inserted into the medullary cavity of the other fracture end (the second fracture end), and manually aligned with the first fracture end, and then the gear 6 is rotated, and the rack 5 is extended. After the left sharp head 2 is firmly placed in the medullary cavity of the second fracture end, the second fracture end is pushed toward the first fracture end, and the gear 6 is retracted. The two fracture ends are brought closer to the center, and the two fractured bones are completely aligned. Reference Figure 3 , the rotating gear 6 can transmit the rack 5 forward, and the left sharp head end 1 is placed into the medullary cavity. With the transmission movement of the rack 5, the rack slide rail bullet head telescopic limit device 12 pops out from the compressed state. When the transmission distance reaches the maximum, the gear 6 is stuck in the gear limit hole 11; refer to Figure 4 , and then push the left sharp head end 2 toward the right sharp head end 22 of the opening and closing angle device for a distance approximately equal to the radius of the gear. The gear slide rail bullet head telescopic limit device 15 is stuck in the gear slide rail limit hole 16, preventing the gear 6 from continuing to retract. The rack slide rail bullet head telescopic limit device 12 prevents the rack 5 from continuing to retract or coming out of the bone marrow cavity, fixing the gear 6 and rack 5 in the mechanical telescopic device so that they cannot move left and right. At this time, the mechanical telescopic device is completely retracted, and the fracture ends of the two bones are well reduced.

[0029] When the temperature of the fixation body reaches above the phase transition temperature, the barbs 3 unfold and return to their initial shape, hooking the surrounding bone marrow, so that the rib internal fixation body is not easy to slip out in the medullary cavity and is fixed more firmly.

[0030] The material used for the internal fixation body is a biodegradable polymer shape memory composite material, whose phase transition temperature is higher than the refrigeration temperature of a medical refrigerator and lower than the normal human body temperature. When the temperature of the internal fixation body is lower than the phase transition temperature, it remains in a temporary shape of shape memory, that is, the barbs 3 are in a folded state and flatly attached to the outer surface of the internal fixation body; after the internal fixation body is placed in the rib medullary cavity, the temperature of the internal fixation body is raised to above the phase transition temperature, and the internal fixation body is stimulated by temperature and automatically returns to the initial shape from the temporary shape of shape memory. Under the action of the restoring force of the shape memory effect, the barbs extend out of the outer surface of the main body. The biodegradable polymer shape memory composite material can meet the rotational rigidity requirements, and it can be automatically degraded into harmless substances in the body, without the need for surgery to remove it again. After recovery, no foreign matter will remain in the body to affect subsequent inspections and treatments, and there will be no effect on chest CT and MRI examinations after absorption.

[0031] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A mechanically rotatable and retractable shape memory absorbable rib internal fixator, comprising an internal fixator axially fixed in the medullary cavity of a rib (1), characterized in that: The internal fixation body adopts a biodegradable polymer shape memory composite material, and comprises a hollow cuboid, with pyramid frames respectively arranged at both ends of the cuboid, and a mechanical telescopic structure arranged inside the cuboid, the mechanical telescopic structure comprising symmetrically arranged racks (5), wherein two racks (5) are respectively meshed by two gears (6); the mechanical telescopic structure retracts and fixes the gears (6) and limits the racks (5) through a bullet-shaped telescopic limiting device; one pyramid frame is a fixed end, and the other pyramid frame is a movable end, and the movable end is a detachable or assembled opening and closing angle device.

2. The shape memory absorbable rib internal fixator capable of mechanical rotation and extension according to claim 1, characterized in that: The pyramid frame at the left end of the rectangular parallelepiped comprises a left sharp head end (2), which is formed by the left ends of two racks (5) extending downward and upward respectively to intersect each other, and the left sharp head end (2) is a fixed end; the pyramid frame at the right end of the rectangular parallelepiped comprises a right sharp head end (22), and the right sharp head end (22) is an opening and closing angle device.

3. The shape memory absorbable rib internal fixator capable of mechanical rotation and extension according to claim 2, characterized in that: The opening and closing angle device comprises a detachable or assembled adjustable bottom plate (17), N angled pieces (18) and N-1 rotating steel columns (19), wherein adjacent angled pieces (18) are hingedly connected via the rotating steel columns (19), the top angle of the pyramid frame is the principal angle (20), the angle between the side angled piece (18) of the pyramid frame and the extended section angled piece (18) is the side angle (21), and the extended section angled piece (18) is connected to the adjustable bottom plate (17).

4. The shape memory absorbable rib internal fixator capable of mechanical rotation and extension according to claim 3, characterized in that: The adjustable bottom plate (17) is located on one side of the cuboid close to the opening and closing angle device, and groove-shaped grooves are respectively provided at both ends of the adjustable bottom plate (17). The angled piece (18) and the adjustable bottom plate (17) are provided with raised edges at corresponding positions, and the raised edges match the groove-shaped grooves.

5. The shape memory absorbable rib internal fixator capable of mechanical rotation and extension according to claim 4, characterized in that: A rack slide rail (7) is provided at one end of the two racks (5) away from the gear (6), a gear slide rail (8) is provided between the two gears (6), and the gear slide rail (8) and the two rack slide rails (7) are connected to an adjustable bottom plate (17); the width of the adjustable bottom plate (17) is smaller than the average inner diameter of the bone marrow cavity of the rib (1).

6. The shape memory absorbable rib internal fixator capable of mechanical rotation and extension according to claim 5, characterized in that: The bullet head telescopic limit device comprises a rack slide rail bullet head telescopic limit device (12) and a gear slide rail bullet head telescopic limit device (15), and the rack slide rail bullet head telescopic limit device (12) is located on the rack slide rail (7).

7. The shape memory absorbable rib internal fixator capable of mechanical rotation and extension according to claim 6, characterized in that: A gear connecting narrow plate (10) is provided between the two gears (6); the middle portion of the gear connecting narrow plate (10) is connected to the metal strip (13) via a knob (4); and the gear slide rail bullet-shaped telescopic limit device (15) is located at an end of the metal strip (13) away from the knob (4).

8. The shape memory absorbable rib internal fixator capable of mechanical rotation and extension according to claim 7, characterized in that: The gear rail (8) is provided with a gear rail limiting groove (14) near one end of the gear (6) and a gear rail limiting hole (16) away from one end of the gear (6); the gear rail bullet-shaped telescopic limiting device (15) is located in the gear rail limiting groove (14) in a compressed state to prevent the gear (6) from moving left and right when the gear (6) is rotated by the knob (4); the gear rail bullet-shaped telescopic limiting device (15) pops out after encountering the gear rail limiting hole (16) and is stuck in the gear rail limiting hole (16), thereby achieving the retraction and fixation of the gear (6); the popped-out rack rail bullet-shaped telescopic limiting device (12) blocks the rack (5) from continuing to retract or coming out of the bone marrow cavity, thereby achieving the limit of the rack (5) and reaching the reset standard.

9. The shape memory absorbable rib internal fixator capable of mechanical rotation and extension according to claim 7, characterized in that: A rack connecting narrow plate (9) is also provided at one end of the two rack slide rails (7) close to the adjustable bottom plate (17), and gear limiting holes (11) arranged at intervals are provided on the rack connecting narrow plate (9), and the two gears (6) can be clamped in the gear limiting holes (11).

10. The shape memory absorbable rib internal fixator capable of mechanical rotation and extension according to claim 1, characterized in that: Barbs (3) arranged at intervals are provided on the pyramid surface of the pyramid frame.

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