Novel extensible long intramedullary rod and matched tool

Abstract

The invention discloses a novel extensible long intramedullary rod and a matched tool, and relates to the technical field of medical instruments, the novel extensible long intramedullary rod comprises a female rod and a male rod, one end of the female rod is provided with a fixed tip, the other end of the female rod is provided with a blind hole, the male rod is sleeved with the blind hole, the fixed tip is used for being connected with the epiphysis of the far end of a long bone, and the end of the male rod is flush with an implantation opening. And the length of the male rod sleeved into the female rod is at least 1 / 2 of the length of the female rod. The extensible long intramedullary rod can effectively fix a long bone, prevent fracture of the long bone and maintain the shape of the long bone, can gradually achieve the purpose of extension along with the growth of the bone, can better maintain the mechanical axis of the bone, has a stronger protection effect on the fracture end, is particularly suitable for being applied to special patients in the department of orthopedics of children, and has a wide application prospect. And intraoperative and postoperative protection of lower limb long bone malformation and fracture caused by osteogenesis insufficiency and congenital long bone artificial joints can be realized.

Description

Technical Field

[0001] This invention relates to the technical field of medical devices, and in particular to a novel extendable intramedullary rod and its supporting tools. Background Technology

[0002] Intramedullary rod technique, also known as intramedullary nailing, is an internal fixation technique that uses metal rods or nails placed within the medullary cavity to fix long bone fractures. The metal rods used are called intramedullary rods. The earliest intramedullary rods were those used by Hey-Groves in 1916, but their use was abandoned due to various complications. In 1939, Kuntscher first introduced the intramedullary nailing technique, establishing the biomechanical principles of intramedullary splinting. In the 1950s, Kuntscher introduced the medullary canal reaming technique, allowing intramedullary nails to fit more accurately into the medullary cavity of the bone shaft, thus improving fixation. Kuntscher's concept of "locking pins" was a precursor to the modern concept of internal locking, expanding the indications for intramedullary nailing. In the early 1980s, intramedullary fixation techniques such as Ender nails and Lottes nails were widely used for various long bone shaft fractures. With the continuous improvement of locking techniques, the advantages of intramedullary nails—strong internal fixation, minimal stress shielding, reduction away from the fracture ends, and minimal disruption to the blood supply to the fracture ends—have been fully realized. Today, intramedullary nailing, including locking intramedullary nailing, is an important method for treating fractures of long bones in the limbs.

[0003] When this technology is applied to the treatment of special diseases in young children, such as osteogenesis imperfecta and congenital tibial pseudoarthrosis, the aforementioned problems that intramedullary rods cannot solve arise: Due to the specific nature of these diseases, the intramedullary rods implanted in long bones must remain in the medullary cavity for a long time to prevent angular deformities and refractures; however, due to the continuous growth of children, in a relatively short period of time, as the overall length of the bone increases and the intramedullary rod becomes relatively shorter, and the tail end of the intramedullary rod gradually moves away from the metaphysis, the bone distal to the tail end of the intramedullary rod loses the protective effect of the rod, and local deformation and angular deformities gradually occur, eventually leading to an inevitable fracture at the junction of the tail end of the intramedullary rod.

[0004] Currently, the novel extended intramedullary rods and related tools used in clinical practice have a tendency for distal displacement of the inner core, and the inner core diameter is small. The inner core cannot effectively maintain the mechanical axis of the tibia and cannot effectively prevent refracture. Summary of the Invention

[0005] The purpose of this invention is to provide a novel extendable intramedullary rod and matching tools to solve the problems existing in the prior art, so that the intramedullary rod can be extended as the bone grows, and can also effectively fix long bones, prevent long bone fractures and maintain the shape of long bones.

[0006] To achieve the above objectives, the present invention provides the following solution: This invention provides a novel extendable intramedullary rod and related tools, including a female rod and a male rod. One end of the female rod is provided with a fixed tip, and the other end is provided with a blind hole, through which the male rod is slidably fitted. The fixed tip is used to connect with the epiphysis of the distal end of the long bone. The end of the male rod is flush with the proximal epiphysis implantation port. The length of the male rod fitted into the female rod is at least 1 / 2 of the length of the female rod. When installing the female rod, an installation wrench is used to detachably connect to the open end of the female rod.

[0007] Preferably, the outer diameter of the female rod is 1mm-3mm smaller than the diameter of the long medullary cavity, and the outer diameter of the male rod is smaller than the inner diameter of the female rod.

[0008] Preferably, the diameters of both the female rod and the male rod are provided in several different sizes; the wall thickness of the female rod is at least 1 mm.

[0009] Preferably, the length of the mother rod is at least 3 / 4 of the length of the long bone; the length of the blind hole is at least 3 / 4 of the length of the mother rod.

[0010] Preferably, the fixing tip has a tapered thread, and during installation, the fixing tip is located within the epiphysis; the length of the fixing tip is less than the thickness of the epiphysis, and the length of the fixing tip is 4mm-10mm.

[0011] Preferably, the inner end of the male rod is provided with a tapered tip and the outer end is provided with a hexagonal socket nut. The inner side of the hexagonal socket nut is provided with a connecting section. The connecting section is externally threaded and is threadedly connected to the proximal epiphyseal implant. The proximal epiphyseal implant is a stepped countersunk hole, and the small end of the stepped countersunk hole is connected to the connecting section. The hexagonal socket nut is located inside the large end of the stepped countersunk hole.

[0012] Preferably, the female rod, the male rod, and the installation wrench are all made of titanium alloy.

[0013] Preferably, the open end of the female rod is provided with an internal thread, and the length of the internal thread is at least 1 cm.

[0014] This invention also relates to a matching tool for a novel extendable intramedullary rod, used in conjunction with the aforementioned novel extendable intramedullary rod. The matching tool is the installation wrench, which includes a threaded rod and a limiting sleeve. The limiting sleeve is fitted over the threaded rod. The threaded rod is used to connect with the open end of the rod during insertion. The limiting sleeve is detachably connected to the rod via a limiting buckle, preventing the rod from rotating when the threaded rod is withdrawn.

[0015] Preferably, the limiting buckle includes a U-shaped notch and a protrusion, the end of the limiting sleeve is provided with at least one of the protrusions, the outer wall of the open end of the mother rod is provided with at least one U-shaped notch, and the protrusion can be inserted into the U-shaped notch; the threaded rod is T-shaped; the length of the installation wrench is at least 1 / 2 of the length of the long bone.

[0016] The present invention achieves the following technical effects compared to the prior art: The elongable intramedullary rod of this invention can effectively fix long bones, prevent long bone fractures, and maintain the shape of long bones. It can also gradually lengthen as the bones grow, better maintain the mechanical axis of the bones, and provide stronger protection for fracture ends. It is especially suitable for special patients in pediatric orthopedics, such as lower limb long bone deformities and fractures due to osteogenesis imperfecta, and intraoperative and postoperative protection of congenital long bone pseudoarthrosis. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the exploded structure of the novel elongable intramedullary rod in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the end structure of the male rod in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the internal hexagonal nut in the male rod of Embodiment 1 of the present invention; Figure 4 This is a partial structural diagram of the mother rod in Embodiment 1 of the present invention. Figure 1 ; Figure 5 This is a partial structural diagram of the mother rod in Embodiment 1 of the present invention. Figure 2 ; Figure 6 This is a schematic diagram of the installation state of the mother rod implanted into the bone in Embodiment 1 of the present invention; Figure 7 This is a schematic diagram of a partial installation structure of the mother rod implanted into the bone in Embodiment 1 of the present invention; Figure 8 This is a schematic diagram of the structure for installing the wrench in Embodiment 2 of the present invention; In the diagram: 1-Female rod, 11-Fixed tip, 12-Blind hole, 13-Internal thread, 14-U-shaped notch, 2-Male rod, 21-Internal hex nut, 22-External thread, 3-Installation wrench, 31-Limiting sleeve, 32-Threaded rod, 33-Protrusion, 4-Long bone, 5-Epiphyseal plate. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be noted that in the description of this invention, the terms "upper," "lower," "left," "right," "inner," "outer," "front," "rear," "clockwise," and "counterclockwise," etc., indicating directional or positional relationships, are based on the directional or positional relationships shown in the accompanying drawings. These are merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," "third," and "fourth" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0021] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] The purpose of this invention is to provide a novel extendable intramedullary rod and matching tools to solve the problems existing in the prior art, so that the intramedullary rod can be extended as the bone grows, and can also effectively fix long bones, prevent long bone fractures and maintain the shape of long bones.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Example 1 like Figures 1 to 7 As shown, this embodiment provides a novel extendable intramedullary rod and supporting tools, including a female rod 1 and a male rod 2. One end of the female rod 1 is provided with a fixed tip 11, and the other end is provided with a blind hole 12, and the male rod 2 is slidably fitted inside. The fixed tip 11 is used to connect with the epiphysis 5 at the distal end of the long bone 4. The end of the male rod 2 is flush with the implantation port of the proximal epiphysis 5. The length of the male rod 2 fitted into the female rod 1 is at least 1 / 2 of the length of the female rod 1. When installing the female rod 1, an installation wrench 3 is detachably connected to the open end of the female rod 1.

[0025] As an optional solution, in this embodiment, the outer diameter of the female rod 1 is 1mm-3mm smaller than the diameter of the medullary cavity of the long bone 4, and the outer diameter of the male rod 2 is smaller than the inner diameter of the female rod 1, so as to facilitate smooth insertion into the female rod 1. Since the medullary cavities of the long bones 4 of the femur and tibia are hollow, it is relatively easy to form a hollow medullary cavity.

[0026] As an optional solution, in this embodiment, both the female rod 1 and the male rod 2 are provided with several different diameter sizes to accommodate the needs of different users. The wall thickness of the female rod 1 is at least 1mm to ensure its strength.

[0027] As an alternative, in this embodiment, the length of the female rod 1 is at least 3 / 4 of the length of the long bone 4; the length of the blind hole 12 is at least 3 / 4 of the length of the female rod 1, which facilitates the accommodation of the male rod 2, while providing sufficient extension and retraction length for the male rod 2 and reserving sufficient space for bone growth.

[0028] As an optional solution, in this embodiment, the fixing tip 11 is a tapered thread, and during installation, the fixing tip 11 is located in the distal epiphysis 5; the length of the fixing tip 11 is less than the thickness of the epiphysis 5 to avoid uneven gaps with the epiphyseal plate, and the length of the fixing tip 11 is 4mm-10mm, which is not greater than the thickness of the epiphysis 5.

[0029] As an optional solution, in this embodiment, the inner end of the male rod 2 is provided with a tapered tip, and the outer end is provided with a hexagonal socket nut 21. A connecting section with an external thread 22 is provided on the inner side of the hexagonal socket nut 21. The connecting section is threadedly connected to the proximal epiphyseal plate 5 implantation port to fix the male rod 2 to the epiphyseal plate 5. The proximal epiphyseal plate 5 implantation port is a stepped countersunk hole, and the small end of the stepped countersunk hole is connected to the connecting section. The hexagonal socket nut 21 is located inside the large end of the stepped countersunk hole, making the surface of the epiphyseal plate 5 smooth.

[0030] As an optional solution, in this embodiment, the open end of the female rod 1 is provided with an internal thread, and the length of the internal thread 13 is at least 1cm, preferably 1cm-2cm, to ensure the reliability of the connection.

[0031] As an optional solution, in this embodiment, the female rod 1, male rod 2, and installation wrench 3 are all made of titanium alloy. Titanium alloy has significant advantages such as high strength, lightweight, corrosion resistance, and biocompatibility. Titanium has excellent biocompatibility with human tissue and will not cause rejection reactions, making it the preferred material for manufacturing artificial joints, dental implants, and heart valves.

[0032] This embodiment features a retractable structure consisting of a female rod 1 and a male rod 2. This structure effectively fixes the long bone 4, prevents fractures of the long bone 4, and maintains the shape of the long bone 4. It can also gradually lengthen as the bone grows, making it particularly suitable for special pediatric orthopedic patients, such as those with osteogenesis imperfecta, deformities and fractures of the long bone 4 in the lower limbs, and for intraoperative and postoperative protection of congenital pseudoarthrosis of the long bone 4. The novel retractable intramedullary rod provides more reliable distal fixation and is less prone to displacement. The designed female rod 1, located at the distal end of the long bone 4, better maintains the mechanical axis of the bone and provides stronger protection for the fracture ends.

[0033] Example 2 like Figure 8 As shown, this embodiment also relates to a new type of extendable intramedullary rod with matching tools for use with the new type of extendable intramedullary rod of the above embodiment 1. The matching tool is an installation wrench 3. As an optional solution, in this embodiment, the installation wrench 3 includes a threaded rod 32 and a limiting sleeve 31. The limiting sleeve 31 is sleeved on the outside of the threaded rod 32. The threaded rod 32 is used to match and connect with the internal thread 13 of the open end of the mother rod 1 when it is inserted. The limiting sleeve 31 is detachably connected (clamped) to the mother rod 1 through a limiting buckle. The threaded rod 32 and the limiting sleeve 31 rotate relative to each other. When the threaded rod 32 is withdrawn, the limiting sleeve 31 prevents the mother rod 1 from rotating synchronously with it.

[0034] As an optional solution, in this embodiment, the length of the installation wrench 3 is at least half the length of the long bone 4, ensuring that the mother rod 1 can be inserted into place. The installation wrench 3 is also made of titanium alloy, ensuring its sturdiness and reliability.

[0035] As an optional solution, in this embodiment, the limiting buckle includes a U-shaped notch 14 and a protrusion 33. At least one protrusion 33 is provided at the end of the limiting sleeve 31, and at least one U-shaped notch 14 is provided on the outer wall of the open end of the female rod 1. The protrusion 33 can be inserted into the U-shaped notch 14. This embodiment provides two symmetrically arranged U-shaped notches 14 and protrusions 33, ensuring balanced connection forces and facilitating insertion and removal operations for rapid positioning.

[0036] As an alternative, in this embodiment, the threaded rod 32 is T-shaped or L-shaped, which is convenient for gripping and rotating.

[0037] Example 3 like Figures 1 to 8As shown, this embodiment provides a novel method for implanting an elongated intramedullary rod, the steps of which are as follows: S1. Based on the diameter and length of the long bone 4 and the long medullary cavity, determine the diameter and other dimensions of the male rod 2 and the female rod 1 to be used; S2, implant positioning to expand the medullary cavity of long bone 4, and rotate and fix the T-shaped sleeve wrench on the blind hole 12 of the mother rod 1; S3, insert the mother rod 1 with the T-shaped socket wrench fixed into the medullary cavity of the long bone 4 through the implantation port until it is in place, and screw the threaded tip of the mother rod 1 through the epiphyseal plate and fix it in the epiphysis 5. S4. Then, use pliers to hold the limiting sleeve 31 of the T-type socket wrench. While keeping the mother rod 1 from rotating and shifting, slowly rotate the threaded rod 32 so that the thread at the front end of the threaded rod 32 separates from the thread at the tail end of the mother rod 1. Then, take out the threaded rod 32 and the limiting sleeve 31 of the T-type wrench from the insertion port in sequence. S5, then the male rod 2 is inserted, and the male rod 2 is inserted into the implantation port and the female rod 1 in sequence; S6. Finally, use an Allen wrench to rotate and fix the flat end of the male rod 2 until the top surface of the flat end is flush with the implantation site.

[0038] In this embodiment, the connection method of the male and female rods 1 is changed. The intramedullary rod that fixes the distal epiphysis 5 of the long bone 4 is designed as a hollow female rod 1, whose distal end is threaded and fixed inside the distal epiphysis 5 of the long bone 4, while the male rod 2 is fixed inside the proximal epiphysis 5 of the long bone 4 and inserted from the proximal end into the hollow blind hole 12 of the female rod 1. This design has several advantages: First, both the male and female rods can be implanted and replaced through an incision in front of the knee joint, resulting in minimal trauma. Second, even if the male rod 2 and female rod 1 slip during growth and bone length increase, the thicker female rod 1, fixed to the distal epiphysis 5 of the long bone 4, remains in the middle and lower segment of the long bone 4, providing good and long-lasting protection for the pseudoarthrosis healing site of the long bone 4. Third, if the condition changes unexpectedly or the male rod 2 elongates to the point of losing axial stability, replacement of the male rod 2 can be considered. For example, if the condition changes unexpectedly during a follow-up examination and the male rod 2 needs to be replaced, the male rod 2 can simply be pulled out from the proximal end of the long bone 4 and a longer male rod 2 can be inserted. Previously, replacing the female rod 1 often required medullary reaming to achieve smooth insertion. In contrast, the improved procedure is simpler, faster, and less invasive. Fourth, for the initial implantation, a longer female rod 1 can be selected, even allowing its tip to pass through the distal epiphysis and be located within the proximal epiphysis 5 of the long bone 4. In this way, the thicker diameter female rod 1 can counteract the deformation tension caused by the non-parallel Kirschner wires on the external fixation device, preventing slippage difficulties between the male and female rods. It also allows the thicker diameter female rod 1 to protect the distal pseudoarthrosis healing site of the long bone 4 for a longer period. Furthermore, the thread depth for fixing the distal epiphysis 5 of the long bone 4 can be increased to reduce the chance of it being pulled out from the distal epiphysis 5 of the long bone 4; or, the thread length for fixing the distal epiphysis 5 of the long bone 4 can be reduced to avoid epiphyseal plate tethering due to threaded fixation, which can result in a crater-like change on X-ray showing epiphyseal plate aggregation around the threads while the epiphyseal plate grows normally in other areas. After the surgery, the bones have recovered, the force alignment has reached the ideal effect, and the bone formation is complete, so it can be removed.

[0039] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "this embodiment," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with the described embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0040] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A novel elongated intramedullary rod, characterized in that: The device includes a female rod and a male rod. One end of the female rod is provided with a fixed tip, and the other end is provided with a blind hole, through which the male rod is slidably fitted. The fixed tip is used to connect with the epiphysis of the distal end of the long bone. The end of the male rod is flush with the proximal epiphysis implantation port. The length of the male rod fitted into the female rod is at least 1 / 2 of the length of the female rod. When installing the female rod, an installation wrench is used to detachably connect to the open end of the female rod.

2. The novel elongable intramedullary rod according to claim 1, characterized in that: The outer diameter of the female rod is 1mm-3mm smaller than the diameter of the long medullary cavity, and the outer diameter of the male rod is smaller than the inner diameter of the female rod.

3. The novel elongable intramedullary rod according to claim 1, characterized in that: The diameter of both the female rod and the male rod is provided in several different sizes; the wall thickness of the female rod is at least 1 mm.

4. The novel elongable intramedullary rod according to claim 1, characterized in that: The length of the mother rod is at least 3 / 4 of the length of the long bone; the length of the blind hole is at least 3 / 4 of the length of the mother rod.

5. The novel elongated intramedullary rod according to claim 1, characterized in that: The fixing tip has a tapered thread, and during installation, the fixing tip is located within the epiphysis; the length of the fixing tip is less than the thickness of the epiphysis, and the length of the fixing tip is 4mm-10mm.

6. The novel elongable intramedullary rod according to claim 1, characterized in that: The male rod has a tapered tip at its inner end and a hexagonal socket nut at its outer end. A connecting section with external threads is provided on the inner side of the hexagonal socket nut. The connecting section is threaded to the proximal epiphyseal implant. The proximal epiphyseal implant is a stepped countersunk hole, and the small end of the stepped countersunk hole is connected to the connecting section. The hexagonal socket nut is located inside the large end of the stepped countersunk hole.

7. The novel elongable intramedullary rod according to claim 1, characterized in that: The female rod, male rod, and installation wrench are all made of titanium alloy.

8. The novel elongable intramedullary rod according to claim 1, characterized in that: The open end of the mother rod is provided with an internal thread, and the length of the internal thread is at least 1 cm.

9. A novel accessory tool for an extendable intramedullary rod, used in conjunction with the novel extendable intramedullary rod as described in any one of claims 1-8, characterized in that: The supporting tool is the installation wrench, which includes a threaded rod and a limiting sleeve. The limiting sleeve is sleeved on the threaded rod. The threaded rod is used to connect with the open end of the female rod when inserted. The limiting sleeve is detachably connected to the female rod through a limiting buckle, so that the female rod does not rotate when the threaded rod is removed.

10. The accessory tool for the novel extendable intramedullary rod according to claim 9, characterized in that: The limiting buckle includes a U-shaped notch and a protrusion. The end of the limiting sleeve is provided with at least one of the protrusions. The outer wall of the open end of the mother rod is provided with at least one U-shaped notch. The protrusion can be inserted into the U-shaped notch. The threaded rod is T-shaped. The length of the installation wrench is at least 1 / 2 of the length of the long bone.

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