Intramedullary reamer and method of assembly

Abstract

The application provides an intramedullary reamer and an assembling method thereof, and relates to the technical field of medical devices. The intramedullary reamer comprises a drill tail, a drill head and a plurality of bead joint structures connected in sequence; the plurality of bead joint structures are connected in series to form a flexible shaft mechanism, the drill tail is connected to one end of the flexible shaft mechanism, and the drill head is connected to the other end of the flexible shaft mechanism. The flexible shaft mechanism has good torque transmission capacity and local bending deformation capacity, can construct multiple bone channels with different directions under a single approach, adapts to complex pelvic anatomical curvature, and realizes accurate guiding and reaming. The application overcomes the defects of the traditional rigid instrument path limitation and the need for multiple punctures, avoids repeated replacement of instruments, significantly shortens the operation time, and reduces tissue damage and radiation exposure. By optimizing the bead joint structure and material ratio, the torsional strength and bending controllability are considered, the reaming efficiency and path adaptability are improved, and a safe and efficient new generation tool is provided for minimally invasive fixation of unstable pelvic fractures.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to an intramedullary reamer and its assembly method. Background Technology

[0002] Pelvic fractures are often caused by high-energy external forces and are frequently accompanied by severe structural displacement and loss of stability. Treatment requires not only anatomical reduction but also emphasizes the robustness and biomechanical rationality of internal fixation. With the advancement of modern orthopedics towards minimally invasive procedures, percutaneous screw fixation has gradually become an important method for treating unstable pelvic fractures due to its advantages of minimal trauma and rapid recovery. This type of surgery typically relies on guidewire guidance, with the hole gradually enlarged and the fixation screw inserted under X-ray fluoroscopy to achieve effective support for the fracture site.

[0003] In this process, the intramedullary reamer, as a key tool for establishing bone channels, directly affects the efficiency and safety of the surgery. Currently, most reamers widely used in clinical practice adopt a rigid rod design with a linear overall structure, allowing only advancement along a pre-set single path. While this design is simple in structure and stable in torsion transmission, it exhibits significant limitations when dealing with complex anatomical areas deep in the pelvis (such as the sacral wing, pubic ramus, and superior acetabular margin): when multiple fixed channels with different orientations need to be constructed to enhance three-dimensional stability, it is necessary to operate through multiple independent puncture points and use multiple sets of instruments to sequentially complete the reaming operation for each path.

[0004] This multi-point approach and frequent instrument changes present a series of clinical challenges: on the one hand, frequent instrument changes and repeated repositioning significantly prolong the operation time, increasing the risk of intraoperative bleeding and the degree of tissue damage; on the other hand, both doctors and patients are exposed to a radiographically guided environment for extended periods, leading to a cumulative increase in radiation dose, which is detrimental to long-term occupational health and patient safety. Furthermore, multiple separate bone tunnels not only damage more surrounding soft tissues but may also affect the synergistic load-bearing capacity between screws due to spatial layout deviations, reducing the overall reliability of fixation.

[0005] Although existing studies have attempted to introduce flexible guiding devices to simplify the approach, most flexible instruments suffer from the problem of balancing stiffness and maneuverability due to limitations in material properties and structural design. They are either flexible in bending but cannot effectively transmit rotational torque, leading to difficulties in hole enlargement; or they are rigid but lack steering ability, still unable to achieve the goal of multi-directional operation with a single instrument.

[0006] To address the aforementioned challenges, there is an urgent need to develop a novel intramedullary reamer capable of adapting to various spatial path requirements through flexible structural adjustments under a single access condition. An ideal design should possess excellent axial transmission performance and local deformation capability, enabling stable reaming like traditional instruments while also allowing for changes in the direction of travel at specific locations to achieve continuous construction of multi-angle channels. In particular, if a modular, interconnected, bead-joint flexible shaft structure could replace the traditional integral rigid rod, it would be possible to provide the instrument with unprecedented path adaptability and operational freedom while ensuring torque transmission efficiency.

[0007] Therefore, overcoming the geometric limitations of existing straight-bar structures and providing a reaming device that integrates compact structure, dynamic deformability, and efficient power transmission has become crucial for improving minimally invasive fixation techniques for pelvic fractures. This invention is proposed against this backdrop, aiming to create a novel intramedullary reaming drill that adapts to complex anatomical pathways and supports multi-directional reaming operations through a flexible transmission system composed of a drill tail, drill bit, and multiple sequentially connected bead-like structures. This provides a safer, more efficient, and low-radiation surgical solution for clinical practice. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the existing technology and provide an intramedullary reamer and its assembly method.

[0009] In a first aspect, the intramedullary reaming drill provided by the present invention includes: a drill tail, a drill bit, and a plurality of beaded structures connected in sequence; the plurality of beaded structures are connected in series to form a flexible shaft mechanism, the drill tail is connected to one end of the flexible shaft mechanism, and the drill bit is connected to the other end of the flexible shaft mechanism.

[0010] In conjunction with the first aspect, the present invention provides a first possible implementation of the first aspect, wherein each of the bead joint structures has a first superior arc groove at one axial end and a first protruding bead adapted to the first superior arc groove at the other end; Multiple beaded structures are connected in series through the first protruding bead and the first superior arc groove, and there is a gap between the opposite end faces of any two adjacent beaded structures.

[0011] In conjunction with the first possible implementation of the first aspect, the present invention provides a second possible implementation of the first aspect, wherein the drill bit is provided with a second superior arc groove adapted to the first protruding ball; With the first protruding bead engaged in the second superior arc groove, there is a gap between the drill bit and the opposite end face of the adjacent bead section structure.

[0012] In conjunction with the second possible implementation of the first aspect, the present invention provides a third possible implementation of the first aspect, wherein the drill breech is provided with a second protruding bead adapted to the first superior arc groove; With the second protruding bead engaged in the first superior arc groove, there is a gap between the drill breech and the opposite end face of the adjacent bead section structure.

[0013] In conjunction with the third possible implementation of the first aspect, the present invention provides a fourth possible implementation of the first aspect, wherein the first protruding bead and the second protruding bead each include: a connecting segment and a bead body connecting the connecting segment; Both the first and second asymmetric grooves are adapted to the bead body, and both the first and second asymmetric grooves are provided with a diameter portion to accommodate the connecting section.

[0014] In conjunction with the fourth possible implementation of the first aspect, the present invention provides a fifth possible implementation of the first aspect, wherein the axis of the first superior arc groove on any of the bead structure is parallel to or spatially perpendicular to the axis of the bead body.

[0015] In conjunction with the first aspect, the present invention provides a sixth possible implementation of the first aspect, wherein the bead structure includes: a first component, a second component, and a connecting block; The first component is hinged to the connecting block around a first pin, and the second component is hinged to the connecting block around a second pin. The first pin and the second pin are perpendicular, and the axis of the first arc groove is parallel to the first pin or the second pin.

[0016] In conjunction with the sixth possible implementation of the first aspect, the present invention provides a seventh possible implementation of the first aspect, wherein one of the first component and the second component is provided with a protrusion, and the other is provided with a groove that is clearance-fitted with the protrusion.

[0017] In conjunction with the first aspect, the present invention provides an eighth possible implementation of the first aspect, wherein the intramedullary reamer has a guide wire hole that extends axially through the drill tail, the flexible shaft mechanism, and the drill bit.

[0018] Secondly, the method for assembling an intramedullary reamer provided by the present invention includes: Multiple beaded structures are connected in sequence, and the multiple beaded structures are connected in series to form a flexible shaft mechanism; Connect the drill shank to one end of the flexible shaft mechanism and connect the drill bit to the other end of the flexible shaft mechanism.

[0019] The embodiments of this invention bring the following beneficial effects: The intramedullary reamer, by employing a flexible transmission system composed of a drill tail, a drill bit, and multiple sequentially connected bead-like structures, overcomes the geometric limitations of traditional rigid straight-rod reamers, significantly improving the flexibility and adaptability of surgical operations. The flexible shaft mechanism formed by the series of bead-like structures possesses both excellent torque transmission capability and the ability to achieve local deformation and path deflection at specific anatomical locations, thereby allowing the construction of multiple bone channels with different orientations under a single access condition. This design effectively avoids the problems of prolonged operation time, aggravated tissue damage, and increased cumulative radiation exposure caused by multiple punctures and repeated instrument changes in existing technologies, significantly shortening the operation time and reducing the risk of intraoperative bleeding and radiation hazards to both doctors and patients.

[0020] Furthermore, due to the dynamically adjustable travel path of the flexible shaft mechanism, it can guide and expand the hole in complex pelvic anatomical structures (such as the sacral wing and pubic ramus) according to the natural curvature, improving the accuracy of bone tunnel positioning and the rationality of screw placement, and enhancing the three-dimensional stability and biomechanical compatibility of internal fixation. Compared with the "insufficient rigidity" or "difficulty in steering" defects often found in existing flexible instruments, this invention optimizes the connection structure and material ratio between the segments, achieving reliable bending maneuverability while ensuring sufficient torsional strength, and balancing hole expansion efficiency and path adaptability. It provides a safe, efficient, and clinically practical new generation surgical tool for minimally invasive fixation of unstable pelvic fractures.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the specific embodiments or related technologies of the present invention, the drawings used in the description of the specific embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 A schematic diagram of the first type of intramedullary reamer provided in an embodiment of the present invention; Figure 2 A schematic diagram of a second type of intramedullary reamer provided in an embodiment of the present invention; Figure 3 A schematic diagram of the bead structure of the first type of intramedullary reamer provided in an embodiment of the present invention; Figure 4 A schematic diagram of the bead structure of the second type of intramedullary reamer provided in an embodiment of the present invention; Figure 5A schematic diagram of the drill tail of an intramedullary reamer provided in an embodiment of the present invention; Figure 6 An exploded view of the bead structure of the second type of intramedullary reamer provided in this embodiment of the invention; Figure 7 A schematic diagram of the first component of the second type of intramedullary reamer provided in an embodiment of the present invention; Figure 8 A schematic diagram of the second component of the second type of intramedullary reamer provided in an embodiment of the present invention; Figure 9 This is a schematic diagram of the drill bit for an intramedullary reamer provided in an embodiment of the present invention.

[0024] Icons: 100-Drill tail; 101-Second protruding bead; 200-Drill bit; 201-Second superior arc groove; 300-Bead joint structure; 301-First component; 302-Second component; 303-Connecting block; 304-Groove; 305-Protrusion; 310-First superior arc groove; 311-Diameter section; 320-First protruding bead; 321-Connecting section; 322-Bead body. Detailed Implementation

[0025] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0026] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," and "third" are only used to describe differences in name and should not be construed as indicating or implying relative importance. Physical quantities in formulas, unless otherwise specified, should be understood as basic quantities in the International System of Units (SI), or derived quantities derived from basic quantities through mathematical operations such as multiplication, division, differentiation, or integration.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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 based on the specific circumstances.

[0028] This invention provides an intramedullary reamer, suitable for establishing multidirectional bone channels during percutaneous screw fixation of pelvic fractures. The intramedullary reamer includes a drill tail 100, a drill bit 200, and multiple sequentially connected beaded structures 300. The multiple beaded structures 300 are connected in series to form a flexible shaft mechanism, which serves as the core component for power transmission and path guidance. The drill tail 100 is connected to one end of the flexible shaft mechanism for connecting to an external drive device (such as an electric drill or manual swivel) to input rotational torque. The drill bit 200 is connected to the other end of the flexible shaft mechanism for performing bone tissue cutting and channel enlargement operations.

[0029] The flexible shaft mechanism consists of several relatively rotatable beaded structures 300. The units are mechanically connected and transmit torque through a bead-groove fit, while also allowing adjacent segments to deflect at different angles in three-dimensional space. This modular series system retains the excellent axial torsion transmission capability of traditional rigid reamers while also enabling the instrument to change its direction of travel at specific anatomical locations within the body. This allows for the construction of multiple bone tunnels with different orientations using a single puncture approach, significantly improving surgical efficiency and safety.

[0030] In use, a guidewire is pre-inserted into the target bone channel, and then the intramedullary reamer of this invention is advanced into the body along the guidewire to the predetermined depth under X-ray fluoroscopy guidance. When the reaming direction needs to be adjusted, the operator can control the posture of the proximal drill tail, combined with distal resistance feedback, to cause the flexible shaft mechanism to produce controllable bending deformation locally, thereby guiding the drill bit into a new anatomical path for continuous reaming. The entire process requires no instrument changes or additional puncture points, effectively reducing surgical trauma and radiation exposure time.

[0031] In this embodiment, the intramedullary reamer includes: a drill tail 100, a drill bit 200, and a plurality of beaded structures 300 connected in sequence; the plurality of beaded structures 300 are connected in series to form a flexible shaft mechanism, the drill tail 100 is connected to one end of the flexible shaft mechanism, and the drill bit 200 is connected to the other end of the flexible shaft mechanism.

[0032] In a preferred embodiment, the number of beaded structures 300 is 5 to 15, the specific number depending on the required enlargement path length and curvature complexity. All beaded structures 300 are standard parts of the same specifications, precision-machined from medical-grade stainless steel or titanium alloy to ensure biocompatibility and mechanical strength. The flexible shaft mechanism is slender and flexible, with an outer diameter between 3mm and 6mm, suitable for percutaneous minimally invasive approaches.

[0033] The drill tail 100 features an interface structure (such as a hexagonal slot or quick-connect coupling) compatible with standard electric or pneumatic orthopedic tools, facilitating rapid installation and disassembly. The drill bit 200 employs a tapered self-tapping design with a cutting edge at the front end, enabling efficient bone reaming. Stable connections between components are achieved through a bead-groove structure between bead joints, allowing for the transmission of high torque (typically 0.5–2.0 N·m) and the withstand of axial thrust (>100 N), meeting clinical reaming requirements.

[0034] Each bead joint structure 300 has a first superior arc groove 310 at one axial end and a first protruding bead 320 that matches the first superior arc groove 310 at the other end; multiple bead joint structures 300 are connected in series through the first protruding bead 320 and the first superior arc groove 310, and there is a gap between the opposite end faces of any two adjacent bead joint structures 300.

[0035] In one specific embodiment, the first superior arc groove 310 is a recessed groove with a circular arc cross-section, and its radius of curvature is slightly larger than the spherical radius of the first protruding bead 320 to form a sliding fit. The first protruding bead 320 is composed of a connecting section 321 and a bead 322 located at the end. The bead 322 is in the shape of a spherical or ellipsoidal shape and is embedded inside the first superior arc groove 310, allowing it to swing freely in two orthogonal planes.

[0036] After connection, the end faces of two adjacent beaded structures 300 maintain a small axial gap of 0.1mm to 0.5mm. This gap design is crucial: on the one hand, it avoids jamming due to thermal expansion and contraction or assembly errors, ensuring flexible movement; on the other hand, it allows for slight compression and misalignment during local bending, improving overall compliance. Experiments show that the maximum deflection angle of a single connection node can reach ±15°, and the entire flexible shaft can achieve a path deviation of over 60° with a total steering angle under the coordinated action of multiple segments.

[0037] The drill bit 200 is provided with a second superior arc groove 201 adapted to the first protruding ball 320; when the first protruding ball 320 is engaged with the second superior arc groove 201, there is a gap between the drill bit 200 and the opposite end face of the adjacent ball joint structure 300.

[0038] In one embodiment, the drill bit 200 has an integrally formed second arc-shaped groove 201 near its proximal end, the geometry and size of which perfectly match the bead 322 of the first protruding bead 320, so that after connection, it can achieve the same hinge function as the intermediate bead joint. After connection, the end face between the drill bit 200 and the last bead joint structure 300 still retains an axial gap of about 0.2mm to prevent the swing from being restricted due to pressure closure.

[0039] This connection method not only ensures that the drill bit 200 can bend and guide synchronously with the flexible shaft mechanism, but also ensures that it will not fall off due to stress concentration during rotation. In addition, because the drill bit participates in the end linkage of the flexible system, it can maintain good centering performance even in a bent state, improving the accuracy and repeatability of the hole reaming trajectory.

[0040] The drill shank 100 is provided with a second protruding bead 101 adapted to the first superior arc groove 310; when the second protruding bead 101 is engaged with the first superior arc groove 310, there is a gap between the drill shank 100 and the opposite end face of the adjacent bead section structure 300.

[0041] In a preferred embodiment, a second protruding bead 101 is provided at the distal end of the drill tee 100. Its structure is the same as that of the aforementioned first protruding bead 320, comprising a connecting section and a bead body. The second protruding bead 101 is inserted into the first superior arc groove 310 of the first bead joint structure 300 to form a reliable ball-and-socket hinge connection.

[0042] In the connected state, an axial clearance of 0.1–0.4 mm is also provided between the drill shank 100 and the first bead structure 300 to ensure that the joint will not lock due to rigid contact when thrust or torsion is applied. This structure gives the drill shank a certain degree of angle adjustment capability, which helps to adapt to the initial guide angle deviation and reduce the difficulty of piercing. At the same time, this connection method can withstand a continuous torque output of up to 2.0 N·m, meeting the power requirements of high-speed hole reaming.

[0043] The first protruding bead 320 and the second protruding bead 101 both include: a connecting section 321 and a bead body 322 connecting the connecting section 321; the first superior arc groove 310 and the second superior arc groove 201 are both adapted to the bead body 322, and the first superior arc groove 310 and the second superior arc groove 201 are both provided with a diameter portion 311 for accommodating the connecting section 321.

[0044] In one embodiment, the bead 322 is a hemispherical structure with a diameter of φ3.2mm, and the connecting section 321 is a cylindrical rod with a diameter of φ2.0mm and a length of 3.0mm, and the two are integrally formed. The bottom surface of the first superior arc groove 310 is a concave spherical surface that matches the bead 322, and the side wall has a radial opening with a width slightly larger than that of the connecting section 321—that is, a "diameter opening 311" with a width of about 2.2mm and a depth penetrating the side wall of the groove.

[0045] The presence of the nozzle 311 allows the connecting section 321 to be laterally embedded into the groove during assembly. After assembly, the ball 322 is confined within the groove cavity and cannot be dislodged, but can swing freely around its own center. This "clamp-in ball-and-socket connection" structure combines high connection strength with flexible rotation characteristics, making it particularly suitable for long-term use under repeated bending and rotation conditions. Experimental verification shows that this connection structure exhibits no significant wear or loosening after 100,000 cycles of oscillation testing.

[0046] The axis of the first superior arc groove 310 on any bead segment structure 300 is parallel to or spatially perpendicular to the axis of the bead body 322.

[0047] In a preferred embodiment, at least a portion of the multiple bead structures 300 are orthogonally arranged, meaning that the axis of the first superior arc groove 310 on a certain bead segment is spatially perpendicular to the axis of its own bead 322. For example, if the groove axis of the current bead segment is along the front-back direction (X-axis), then the bead axis of its protruding bead extends along the left-right direction (Y-axis).

[0048] This alternating arrangement allows the flexible shaft mechanism to have differentiated bending priority directions in different segments, and through reasonable arrangement, omnidirectional bending capability can be achieved. For example, a beaded chain with alternating X-axis and Y-axis hinges can bend alternately in the horizontal and vertical planes, ultimately forming a spiral or S-shaped spatial path, which greatly enhances the compliance with complex anatomical structures (such as the sacroiliac joint, pubic ramus angle, etc.).

[0049] Another implementation method is to use a "parallel arrangement" for all beads, that is, the groove axis and the convex bead axis are collinear. This is suitable for applications where the bends are mainly in one plane, and the structure is simpler and the manufacturing cost is lower.

[0050] The bead joint structure 300 includes: a first component 301, a second component 302, and a connecting block 303; the first component 301 and the connecting block 303 are hinged around a first pin, the second component 302 and the connecting block 303 are hinged around a second pin, the first pin and the second pin are perpendicular, and the axis of the first arc groove 310 is parallel to the first pin or the second pin.

[0051] In one advanced embodiment, the bead joint structure 300 is not a single integral part, but a Hooke's joint type composite structure composed of three independent components. Specifically: the connecting block 303 is a central transition member with mutually perpendicular pin holes on both sides; the first component 301 passes through the pin hole on one side of the connecting block 303 through a first pin shaft, realizing the rotational degree of freedom in the pitch direction; the second component 302 passes through the pin hole on the other side of the connecting block 303 through a second pin shaft, realizing the rotational degree of freedom in the yaw direction; the two rotational degrees of freedom are orthogonally superimposed to form a typical universal joint motion mechanism, significantly improving the range of motion of a single node.

[0052] The first superior arc groove 310 is provided on the first component 301, and its axis is parallel to the first pin; while the first protruding bead 320 is provided on the second component 302, and its axis is parallel to the second pin. This arrangement enables each bead segment structure 300 to have two degrees of freedom of movement, further enhancing the path adaptability of the entire flexible shaft.

[0053] Although the structure has a large number of parts, its overall compactness is still maintained through miniaturization (the length of a single bead section is ≤6mm). The connecting pins adopt anti-loosening structures (such as elastic retaining rings or welded caps) to prevent them from falling off during surgery.

[0054] One of the first component 301 and the second component 302 is provided with a protrusion 305, and the other is provided with a slot 304 that fits with the protrusion with a clearance. In an improved embodiment, in order to enhance the torsional stiffness between the first component 301 and the second component 302 and limit excessive swaying, an auxiliary guide structure is added between them: specifically, the second component 302 is provided with a pair of symmetrically distributed protrusions 305 (such as rectangular bosses), and the first component 301 is provided with a matching slot 304 at the corresponding position.

[0055] A clearance of 0.05–0.15 mm is maintained between the protrusion 305 and the groove 304, which allows relative rotation while serving as circumferential positioning and shear force transmission. When the flexible shaft transmits large torques, this structure can share part of the load, reduce the pressure at the ball-groove connection, and extend service life.

[0056] Furthermore, the opening direction of the notch 304 determines the maximum permissible bending plane, which can be used to directionally control the bending tendency of the flexible shaft and assist doctors in predicting the path. For example, if the notch extends along the Y-axis, the flexible shaft will preferentially bend in the XZ plane, which is beneficial for preoperative planning and intraoperative manipulation.

[0057] The intramedullary reaming drill has a guide wire hole that extends axially through the drill tail 100, the flexible shaft mechanism, and the drill bit 200. In a key embodiment, the guide wire hole is a through hole that starts from the tail end inlet of the drill tail 100, continuously passes through the first protruding bead 320 of each bead joint structure 300, the connecting area of ​​the first superior arc groove 310, the center of the connecting block 303, and the axis of the drill bit 200, and finally exits from the tip of the drill bit to form a complete guide wire channel.

[0058] The inner diameter of the guide wire hole is uniformly φ0.8~1.2mm, compatible with commonly used guide wires (guide wire diameter is usually 0.9~1.0mm). Throughout the bending process, the guide wire hole remains unobstructed; even when the flexible shaft is at maximum deflection, no folding or blockage occurs. This is thanks to the optimized spatial design of the connecting section and the orifice in the bead joint structure, ensuring a continuous and smooth internal passage.

[0059] The guidewire not only provides a precise navigation reference for the reamer but also serves as a safety traction line to assist in retrieval in case of instrument breakage or jamming. More importantly, the entire process is guided by the guidewire, which conforms to existing clinical operating practices without requiring changes to the physician's existing skill set, thus facilitating its widespread use.

[0060] An assembly method for an intramedullary reamer includes: sequentially connecting multiple beaded structures 300 and connecting the multiple beaded structures 300 in series to form a flexible shaft mechanism; connecting the drill tail 100 to one end of the flexible shaft mechanism and connecting the drill bit 200 to the other end of the flexible shaft mechanism.

[0061] In a typical assembly process, assembly is completed using the following steps: 1. Prepare several beaded structures of the same specification 300 (or prepare beads of different orientations in a predetermined order). 2. Align the first protruding bead 320 of the first bead section with the first superior arc groove 310 of the second bead section, and use radial extrusion to make the connecting section 321 pass through the diameter portion 311 until the bead 322 is completely embedded in the groove cavity. 3. Repeat the above steps to connect the remaining bead structures 300 one by one to form a complete flexible shaft chain; 4. Insert the second protruding bead 101 of the drill shank 100 into the first superior arc groove 310 of the first bead section to complete the proximal connection; 5. Fit the second superior arc groove 201 of the drill bit 200 onto the first protruding ball 320 of the last ball joint to complete the remote connection; 6. Check that each connection node rotates freely without jamming, and confirm that the guidewire can pass smoothly throughout the entire length; 7. Conduct torque loading tests and simulated bending tests, and sterilize and package the products after they pass the tests.

[0062] This assembly method is simple and efficient, and suitable for mass production on automated production lines. For composite bead joints using a Hooke hinge structure, the pin hinges of the three internal components must be completed before they are assembled into a whole.

[0063] In summary, this invention, through its innovative bead-joint flexible shaft structure, successfully solves the problems of multiple access routes, high radiation, and low flexibility faced by traditional rigid reamers when treating complex pelvic fractures. The proposed various bead-joint configurations (integral and Hooke hinge type), connection methods (convex bead-groove + orifice), arrangement strategies (orthogonal / parallel axes), and guidewire penetration design collectively constitute a highly integrated, safe, reliable, and clinically practical novel intramedullary reamer system.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An intramedullary reaming drill, characterized in that, include: The drill tail (100), the drill bit (200), and multiple sequentially connected beaded structures (300). Multiple beaded structures (300) are connected in series to form a flexible shaft mechanism, the drill shank (100) is connected to one end of the flexible shaft mechanism, and the drill bit (200) is connected to the other end of the flexible shaft mechanism; Each of the bead joint structures (300) has a first superior arc groove (310) at one axial end and a first protruding bead (320) adapted to the first superior arc groove (310) at the other end; multiple bead joint structures (300) are connected in series through the first protruding bead (320) and the first superior arc groove (310), and there is a gap between the opposite end faces of any two adjacent bead joint structures (300); The bead joint structure (300) includes: a first component (301), a second component (302), and a connecting block (303); the first component (301) and the connecting block (303) are hinged around a first pin, the second component (302) and the connecting block (303) are hinged around a second pin, and the first pin is perpendicular to the second pin; The first superior arc groove (310) is provided on the first component (301), and its axis is parallel to the first pin; the first protruding ball (320) is provided on the second component (302), and its axis is parallel to the second pin.

2. The intramedullary reamer according to claim 1, characterized in that, The drill bit (200) is provided with a second arc groove (201) adapted to the first protruding ball (320); With the first protruding bead (320) engaged with the second superior arc groove (201), there is a gap between the drill bit (200) and the opposite end face of the adjacent bead structure (300).

3. The intramedullary reamer according to claim 2, characterized in that, The drill nut (100) is provided with a second protruding ball (101) adapted to the first superior arc groove (310). With the second protruding bead (101) engaged with the first superior arc groove (310), there is a gap between the drill tail (100) and the opposite end face of the adjacent bead section structure (300).

4. The intramedullary reamer according to claim 3, characterized in that, The first protruding bead (320) and the second protruding bead (101) each include: a connecting segment (321) and a bead body (322) connecting the connecting segment (321); The first superior arc groove (310) and the second superior arc groove (201) are both adapted to the bead (322), and the first superior arc groove (310) and the second superior arc groove (201) are both provided with a diameter portion (311) for accommodating the connecting section (321).

5. The intramedullary reamer according to claim 4, characterized in that, The axis of the first superior arc groove (310) on any of the bead structure (300) is parallel to or spatially perpendicular to the axis of the bead body (322).

6. The intramedullary reamer according to claim 1, characterized in that, One of the first component (301) and the second component (302) is provided with a protrusion (305), and the other is provided with a groove (304) that is clearance-fitted with the protrusion.

7. The intramedullary reamer according to claim 1, characterized in that, The intramedullary reaming drill has a guide wire hole that extends axially through the drill tail (100), the flexible shaft mechanism, and the drill bit (200).

8. A method for assembling an intramedullary reamer, characterized in that, include: Multiple beaded structures (300) are connected in sequence, and the multiple beaded structures (300) are connected in series to form a flexible shaft mechanism; Connect the drill shank (100) to one end of the flexible shaft mechanism and connect the drill bit (200) to the other end of the flexible shaft mechanism; Each of the bead joint structures (300) has a first superior arc groove (310) at one axial end and a first protruding bead (320) adapted to the first superior arc groove (310) at the other end; multiple bead joint structures (300) are connected in series through the first protruding bead (320) and the first superior arc groove (310), and there is a gap between the opposite end faces of any two adjacent bead joint structures (300); The bead joint structure (300) includes: a first component (301), a second component (302), and a connecting block (303); the first component (301) and the connecting block (303) are hinged around a first pin, the second component (302) and the connecting block (303) are hinged around a second pin, and the first pin is perpendicular to the second pin; The first superior arc groove (310) is provided on the first component (301), and its axis is parallel to the first pin; the first protruding ball (320) is provided on the second component (302), and its axis is parallel to the second pin.

Images