3mm-level micro rope-driven needle forceps for minimally invasive surgery

Abstract

The invention discloses 3mm-level micro rope-driven needle forceps for minimally invasive surgery, and belongs to the technical field of medical instruments, the needle forceps are composed of an instrument tube, an instrument base, an instrument wrist part, a forceps head and a superfine rope, and precise clamping and flexible rotation are cooperatively realized; the instrument tube is a hollow titanium alloy long rod and allows the superfine rope to penetrate through. The instrument base comprises a base connecting part and a forked cavity part, and the forked cavity part is provided with a superfine rope hole, an arc-shaped guide surface and an arc-shaped lug plate and is connected with the wrist part; the instrument wrist part is provided with a lug plate structure, a main body structure and a cross structure, the lug plate structure is provided with an annular groove and a shaft hole, the main body structure is provided with a superfine rope through hole, an additional material protrusion and a limiting swing angle, and the cross structure is provided with a protruding block, a limiting end and a limiting tong head; the clamp heads are two symmetrical clamp bodies, and clamp teeth are meshed in a crossed mode to improve stability. The superfine ropes are three sets of medical stainless steel ropes or tungsten wire ropes and drive the forceps head to be opened and closed and the wrist to rotate. The needle holding forceps are optimized in structure, accurate in operation, high in space adaptability and capable of meeting fine operation requirements of minimally invasive surgery.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a 3mm-class miniature tether-driven needle holder for minimally invasive surgery. Background Technology

[0002] With the continuous development of medical technology, minimally invasive surgery has been widely used in surgical fields such as general surgery, cardiothoracic surgery, and neurosurgery due to its advantages of less trauma, faster recovery, and fewer postoperative complications. In minimally invasive surgery, the needle holder is a core operating instrument, mainly used to hold the suture needle to complete tissue suturing. Its performance directly affects the efficiency of surgery and the quality of suturing, placing extremely high demands on the miniaturization of instruments, operational precision, and spatial adaptability.

[0003] Currently, most minimally invasive surgical needle holders on the market use rigid transmission structures or traditional rope-driven methods. Among them, needle holders with rigid transmission structures are limited by their own structure, making it difficult to further reduce their overall size. They lack flexibility in confined surgical spaces (such as intracranial or deep thoracic cavities), are prone to interference with surrounding tissues, and are difficult to accurately reach the operating site. Traditional rope-driven needle holders typically have an instrument tube diameter of ≥8mm. If reduced to 3mm, the rope hole diameter is ≤0.5mm, requiring 'absolute coaxial alignment' during threading, resulting in a high threading failure rate on automated production lines.

[0004] Furthermore, existing needle holders often employ planar contact or simple toothed designs for their clamping heads, which can easily lead to slippage when gripping small suture needles. They also lack effective opening and closing mechanisms; excessive closure may damage the suture needle or tissue, while excessive opening can reduce clamping stability. Additionally, some needle holders have limited wrist rotation angle adjustment ranges, failing to meet the multi-angle operation requirements of complex surgical scenarios, further hindering the development of precision in minimally invasive surgery. Therefore, developing a needle holder that combines miniaturization, high-precision control, strong spatial adaptability, and stable clamping performance has become a key direction for overcoming the current technological bottlenecks in minimally invasive surgical instruments. Summary of the Invention

[0005] In view of this, embodiments of the present invention provide a 3mm-class miniature tether-driven needle holder for minimally invasive surgery, which at least partially solves the problems in the prior art.

[0006] This invention provides a 3mm-class miniature cord-driven needle holder for minimally invasive surgery, comprising an instrument tube, an instrument base, an instrument wrist, a forceps head, and an ultrafine cord;

[0007] The instrument tube is a hollow TC4 titanium alloy long rod with an outer diameter of 3mm, an inner diameter of 2.6mm, and a wall thickness of 0.2mm±0.02mm, used for threading ultra-fine ropes.

[0008] The instrument base includes a base connecting part and a bifurcated cavity part. The base connecting part has an outer diameter of 2.6 mm and a length of 3.0 mm. The base connecting part is nested with the inner diameter of the instrument tube. The head of the bifurcated cavity part extends into a bifurcated arc-shaped ear plate structure. The left and right end faces of the bifurcated cavity part are provided with a first set of ultra-fine rope holes and a second set of ultra-fine rope holes. The front and rear end faces are provided with a third set of ultra-fine rope holes with a diameter of 0.6 mm. The end faces are provided with arc-shaped guide surfaces with an arc radius of 0.9 mm. The arc-shaped ear plate structure is provided with a first shaft hole with a diameter of 0.8 mm.

[0009] The wrist of the device includes an ear plate structure, a main body structure, and a cross structure. The ear plate structure is a cylinder with a thickness of 0.66 mm. It has a first annular groove with a 20° bevel and a 0.15 mm arc around its circumference and a second shaft hole in the center. The main body structure has a fourth and a fifth ultra-fine rope through hole symmetrically arranged on both sides. It has additive protrusions on the lower two sides. The cross structure has a protrusion on the upper part, a limiting end on the left and right ends, and a connecting shaft at the front and back.

[0010] The pliers head includes symmetrical pliers head A and pliers head B. Both pliers head A and pliers head B include a hinge end, a pliers head body and pliers teeth. The hinge end is provided with an annular groove and a third shaft hole, and the pliers teeth are cross-engaged.

[0011] The ultra-fine rope consists of three sets of six medical stainless steel ropes, each with a diameter of 0.3mm. They are threaded through corresponding rope holes and grooves to drive the opening and closing of the forceps head and the rotation of the instrument wrist.

[0012] According to a specific implementation of the present invention, the edge of the threading hole of the bifurcated cavity of the instrument base is subjected to a small amount of plastic deformation by stamping, micro-forging, riveting, spinning or laser hot deformation processes to form an arc-shaped guide surface, allowing the ultrafine rope to be inserted with an angle deviation of ±15°.

[0013] According to a specific implementation of an embodiment of the present invention, the additive protrusion of the wrist of the instrument is integrally formed with the main structure through additive manufacturing technology. When the wrist of the instrument rotates around the axis, the additive protrusion contacts and interferes with the arc-shaped ear plate structure of the instrument base, limiting the swing angle of the wrist of the instrument to ±33°, the swing angle limit error ≤1°, and the left and right swing angle symmetry error ≤0.5°.

[0014] According to a specific implementation of the present invention, the protrusion of the cross structure of the instrument wrist is used for limiting the closing of the pliers head. When pliers head A and pliers head B close to the center to a predetermined position, the protrusion blocks the pliers head from continuing to rotate, preventing excessive closing.

[0015] According to a specific implementation of the present invention, the limiting end of the cross structure of the instrument wrist is used to limit the opening of the pliers head. When pliers head A and pliers head B are opened, the limiting end limits the maximum opening angle of the pliers head to 50°, and the limiting error is ≤1°, ensuring that the opening range is within a reasonable range.

[0016] According to a specific implementation of an embodiment of the present invention, the ultrafine rope is a 0.3mm medical stainless steel rope or a 0.2mm tungsten wire rope, including a first group of ultrafine ropes, a second group of ultrafine ropes and a third group of ultrafine ropes.

[0017] The first set of ultra-fine ropes passes through the first set of ultra-fine rope holes and the fourth ultra-fine rope through hole and is inserted into the annular groove of the pliers A, which is used to drive the pliers A to open and close.

[0018] The second set of ultra-fine ropes passes through the second set of ultra-fine rope holes and the fifth ultra-fine rope through hole and is inserted into the annular groove of the pliers B, which is used to drive the pliers B to open and close.

[0019] The third set of ultra-fine ropes is wound around the first annular groove of the ear plate structure through the third set of ultra-fine rope holes, and is used to drive the rotation of the instrument wrist.

[0020] According to a specific implementation of the present invention, the jaw teeth of the pliers A and the jaw teeth of the pliers B are positioned one tooth apart, forming a "tooth tip and tooth root cross meshing" structure when closed, thereby improving clamping stability and biting force.

[0021] According to a specific implementation of the present invention, the second shaft hole of the wrist ear plate structure of the instrument is connected to the first shaft hole of the arc-shaped ear plate structure of the instrument base through a wrist pivot and a pivot cap, thereby providing a fulcrum for wrist rotation.

[0022] According to a specific implementation of the present invention, the jaw A and jaw B of the clamps are connected by a hinge shaft, and the third shaft hole at the hinge end is hinged to the connecting shaft of the cross structure of the instrument wrist, so that the jaws can rotate flexibly around the shaft to open and close.

[0023] According to a specific implementation of an embodiment of the present invention, when the first set of ultrafine ropes and the second set of ultrafine ropes are tightened simultaneously, the tension is converted into torque, which drives the clamp heads A and B to close towards the center; when they are relaxed simultaneously, the clamp heads A and B open, and precise positioning is achieved through the protrusions and the limiting end, ensuring operational safety.

[0024] The present invention has the following beneficial effects:

[0025] This invention adopts a 3mm-level miniaturized design, with the instrument tube being a hollow titanium alloy long rod. The overall structure is compact, allowing it to easily penetrate into narrow surgical spaces such as the intracranial cavity and deep thoracic cavity, effectively avoiding interference with surrounding tissues. It solves the problem that traditional rigid transmission needle holders are difficult to adapt to complex minimally invasive scenarios due to size limitations, thus assisting in precise surgical operations.

[0026] The bifurcated cavity section features an arc-shaped guide surface design, providing a stable threading channel with a ±15° tolerance angle for the ultra-fine cord, significantly reducing the failure rate of automated threading and cord wear. Simultaneously, three sets of ultra-fine cords drive the opening and closing of the clamp head and the rotation of the wrist, resulting in a clear transmission path and sensitive response. This solves the problem of low control precision in traditional cord-driven needle forceps, ensuring precise and controllable clamp head movement and wrist rotation, and reducing the difficulty of surgical operations.

[0027] The forceps head adopts a forceps tooth structure with cross-meshing of tooth tips and teeth, which greatly improves the clamping stability of small suture needles and prevents slippage; and the cross structure of the instrument wrist is equipped with a protrusion and a limiting end, which respectively realizes the clamp head closing and opening 50° limiting, avoiding the problems of excessive closure damaging suture needles or tissues, and excessive opening reducing clamping stability, thus providing a strong guarantee for the quality and safety of surgical suturing.

[0028] The wrist of the instrument is connected to the instrument base through the ear plate structure to form a precision shaft. With the addition of the protrusion, the swing angle (±33°) is reasonably limited, which ensures that the wrist can rotate flexibly and the rotation angle can be controlled. It can meet the multi-angle operation needs in complex surgical scenarios, break through the limitation of the limited adjustment range of some needle forceps wrists, and further promote the development of precision in minimally invasive surgery. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, 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.

[0030] Figure 1 is a schematic diagram of the overall structure of a 3mm-class miniature cord-driven needle holder;

[0031] Figure 2 is a schematic diagram of the assembly structure of the instrument base, instrument wrist and clamp head in a 3mm-class miniature cord-driven needle forceps.

[0032] Figure 3 is a three-dimensional structural diagram of the base of a 3mm-class miniature cord-driven needle clamp instrument;

[0033] Figure 4 is a three-dimensional structural diagram of the wrist of a 3mm-class miniature cord-driven needle clamp instrument;

[0034] Figure 5 is a schematic diagram of the assembly structure of the wrist and the head of the 3mm-class miniature cord-driven needle forceps.

[0035] Figure 6 is a schematic diagram of the mating structure between the 3mm-class miniature cord-driven needle holder head and the wrist limiting structure of the instrument;

[0036] Figure 7 is a schematic diagram of the 3mm-class miniature cord-driven needle clamp with the clamp head closed.

[0037] Figure 8 is a schematic diagram of the cooperation structure between the additive protrusion at the wrist of the 3mm-class miniature cord-driven needle forceps and the arc-shaped ear plate structure of the instrument base.

[0038] Figure 9 is a schematic diagram of the arc-shaped guide surface of the base of the 3mm-class miniature cord-driven needle clamp instrument;

[0039] Figure 10 is a schematic diagram of the arc-shaped guide surface of the base of the 3mm-class miniature cord-driven needle clamp instrument from another perspective. Detailed Implementation

[0040] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0041] Conventional lanyard-driven surgical instruments employ a modular drive design, with the drive components concentrated in the base. Motion is transmitted to the distal actuator (forceps) via lanyards. The instrument tube is typically a metal tubular structure with an internal traction rope channel. Under current mature processes, the instrument tube diameter is mostly 8mm, enabling single-degree-of-freedom end-effector manipulation. Further miniaturization of the instrument tube presents three core challenges: Firstly, reduced tube diameter leads to insufficient space for traction rope placement, easily causing motion interference or tension loss, hindering multi-degree-of-freedom manipulation. Secondly, when the rope hole diameter is ≤0.5mm, the drive rope requires "absolute coaxial alignment" for insertion, but in practice, due to instrument vibration and human error (especially on automated production lines), the threading failure rate increases significantly, limiting mass production feasibility. Thirdly, multi-degree-of-freedom manipulation requires precise alignment of the limiting structure; miniaturized traditional limiting designs are difficult to adapt, easily leading to overtravel or functional failure.

[0042] To overcome this technological bottleneck, see [link / reference]. Figures 1-10 This invention proposes a 3mm-level ultra-fine rope-driven multi-degree-of-freedom needle holder. Through structural design innovation and process optimization, the instrument tube diameter is reduced from 4mm to 3mm while maintaining performance without degradation. It also achieves multi-degree-of-freedom operation and simultaneously solves the problems of spatial constraints, wire threading, and limit alignment. This provides a key solution for the miniaturization breakthrough of rope-driven surgical instruments.

[0043] See Figure 1 The present invention discloses a 3mm-level multi-degree-of-freedom needle holder based on ultra-fine rope transmission, comprising: instrument tube (1), instrument base (2), instrument wrist (3), pliers head (4), and ultra-fine rope (5).

[0044] Instrument tube (1) Hollow tube, used for threading and guiding ultra-fine ropes to the operating end. The main body is a long rod-shaped tube with a special opening structure on the left end. It is made of titanium alloy and has a length of 100mm, an outer diameter of 3mm, an inner diameter of 2.6mm, and a wall thickness of 0.2mm.

[0045] The instrument base (2), with an overall length of 8.5 mm, is a key component connecting the instrument tube (1) and the instrument wrist (3). It includes a base connection part (21) for nesting with the instrument tube (1) and a bifurcated cavity part (22) for guiding the ultra-fine rope and realizing the axial connection of the instrument wrist (3).

[0046] The base connection part (21) is 3.0 mm long and 2.6 mm in outer diameter, which is perfectly matched with the inner diameter (2.6 mm) of the instrument tube (1), forming a precise nested fit to ensure the overall concentricity and structural stability of the two after connection.

[0047] The main body of the bifurcated cavity (22) is cylindrical concave cavity, with a main body length of 4.5 mm and a diameter of 3.0 mm. A pair of bifurcated arc-shaped ear plate structures (226) extend from its head, with a radius of 1.0 mm.

[0048] The main body of the bifurcated cavity (22) is provided with a first set of ultra-fine rope holes (221) on the left and right end faces, a second set of ultra-fine rope holes (222) and a third set of ultra-fine rope holes (223) on the front and rear end faces, all with a diameter of 0.6 mm, for the precise insertion of ultra-fine ropes.

[0049] The main end face of the bifurcated cavity (22) is also provided with an arc-shaped guide surface (224) with an arc radius of 0.9 mm, which provides a smooth transition guide within a certain angle range for the ultra-fine rope and reduces wear on the ultra-fine rope.

[0050] The arc-shaped ear plate structure (226) of the bifurcated cavity part (22) is provided with a first shaft hole (225) with a diameter of 0.8mm, which is used to achieve shaft connection with the wrist part (3) of the instrument to ensure rotational freedom.

[0051] The wrist of the instrument (3) connects the instrument base (2) and the clamp head (4), transmits the driving force of the ultra-fine rope, and is also used for clamp closing limit and opening angle limit. It also drives the clamp head (4) to achieve rotation within a range of ±33°. It includes an ear plate structure (31), a main body structure (32) and a cross structure (33).

[0052] The ear plate structure (31) is cylindrical with a thickness of 0.66 mm and is located on the lower surface of the main structure (32). Its circumferential surface has a first annular groove (311) with a 20° inclined surface and a radius of 0.15 mm. It is designed specifically for the transmission of ultra-fine ropes, which can both ensure the positioning of ultra-fine ropes and reduce friction loss. The center of the cylinder is the second shaft hole (312), which forms a precision shaft connection with the first shaft hole (225) of the instrument base (2) through the wrist pivot and pivot cap, providing a fulcrum for the overall rotation.

[0053] The main structure (32) is cylindrical, with the cross structure (33) and ear plate structure (31) connected to the upper and lower surfaces respectively. The fourth ultra-fine rope through hole (321) and the fifth ultra-fine rope through hole (322) are symmetrically arranged on both sides of the cross structure (33) and ear plate structure (31) to serve as channels for the ultra-fine rope to pass through, ensuring the straightness of power transmission.

[0054] On the lower sides of the fourth ultra-fine rope through hole (321) and the fifth ultra-fine rope through hole (322), additive protrusions (323) are designed for the swing angle limit of the wrist of the instrument (3).

[0055] The cross structure (33) has a semi-circular body integrated on the upper part of the cuboid structure to form a "cross" feature. A protrusion (331) is provided on the top of the semi-circular body to achieve precise positioning when the pliers (4) are closed, preventing over-closing. The limiting ends (332) at the left and right ends of the connection between the semi-circle and the cuboid limit the maximum opening angle of the pliers head to ensure operational safety. A connecting shaft (333) is provided at the front and back of the connection between the semi-circle and the cuboid, which is connected to the second shaft hole (4112, 4212) of the hinge end (411, 421) of the pliers head A (41) and the pliers head B (42) to provide a rotation fulcrum for opening and closing the pliers head.

[0056] The clamp head (4) is the execution end of the needle holder and adopts a split design. It consists of symmetrical clamp head A (41) and clamp head B (42). The two are linked to the wrist of the instrument (3) through the hinge shaft (43) to complete the precise clamping action together.

[0057] Both clamp head A (41) and clamp head B (42) include hinged ends (411, 421) for connecting with the wrist of the instrument (3) and transmitting force through the ultra-fine rope; clamp head body (412, 422) for bearing the clamping function and having a serrated biting surface; clamp teeth (413, 423) for providing anti-slip clamping and ensuring that the object being operated does not slip.

[0058] The position of the jaw teeth (423) of jaw head B (42) differs from that of the jaw teeth (413) of jaw head A (41) by one tooth position. When the hinge ends are aligned, a structure of "tooth tip and tooth root cross meshing" is formed. This design can significantly improve the stability of clamping and the biting force.

[0059] The hinge end (411, 421) is a ring structure with an annular groove (4111, 4211) on its circumferential surface for threading a fine rope. The opening and closing action of the clamp head is achieved by the traction of the fine rope. The center of the ring has a third shaft hole (4112, 4212) that forms a hinge with the connecting shaft (333) of the cross structure (33) of the wrist of the instrument (3). This structure allows the clamp head to rotate flexibly around the shaft.

[0060] The ultra-fine rope can be composed of three groups of six ultra-fine ropes, made of medical-grade stainless steel with a diameter of 0.3mm, or medical-grade tungsten wire rope with a diameter of 0.2mm.

[0061] After the first set of ultra-fine ropes is inserted into the instrument tube (1), it is guided by the first ultra-fine rope hole (221) of the bifurcated cavity part (22) of the instrument base (2), and finally passes through the fourth ultra-fine rope through hole (321) of the instrument wrist part (3) and passes through the annular groove (4111) of the hinge end (411) of the pliers head A (41) to drive the opening and closing of the pliers head A (41).

[0062] By pulling and releasing the two ends of the ultra-fine rope, a closed-loop transmission is formed:

[0063] (A) When tightening, the tension is converted into torque through the annular groove (4111), driving the pliers A (41) to rotate around the hinge axis (43) in the closing direction.

[0064] (B) When relaxing, the force of the clamp head B (42) or the reset mechanism will cause the clamp head A (41) to move in the opening direction.

[0065] After the second set of ultra-fine ropes enters from the instrument tube (1), it is guided by the second ultra-fine rope hole (222) of the bifurcated cavity part (22) of the instrument base (2), and finally passes through the fifth ultra-fine rope through hole (322) of the instrument wrist part (3) and passes through the annular groove (4211) of the hinge end (421) of the pliers head B (42) to drive the opening and closing of the pliers head B (42).

[0066] After the third set of ultra-fine ropes passes through the instrument tube (1), it passes through the third ultra-fine rope hole (223) of the bifurcated cavity (22) of the instrument base (2) and enters the first annular groove (311) on the circumferential surface of the ear plate structure (31) of the instrument wrist (3), forming a circumferential insertion. This arrangement allows the tension of the ultra-fine ropes to be converted into torque through the annular groove, driving the wrist to rotate around the connecting shaft between the second shaft hole (312) and the first shaft hole (225).

[0067] The first set of ultrafine ropes and the second set of ultrafine ropes are respectively connected to clamp head A (41) and clamp head B (42). By synchronously "tightening" or "relaxing", the clamp head (4) is driven to rotate in opposite directions (opening and closing) around the hinge axis:

[0068] (A) When clamping, the tension is converted into torque. The first set of ultra-fine ropes and the second set of ultra-fine ropes tighten synchronously. When the clamp head A (41) and clamp head B (42) close around the hinge axis, they cannot continue to rotate inward due to the "blocking" of the central protrusion (331), and are forced to stop rotating. This achieves precise positioning when the clamp head (4) closes, preventing excessive closure from damaging tissues or instruments, while ensuring stable clamping force.

[0069] (B) When released, the torque disappears, and the first set of ultra-fine ropes and the second set of ultra-fine ropes relax synchronously, causing the clamp head A (41) and clamp head B (42) to open. Due to the "restriction" of the limiting end (332) of the cross structure (33) of the wrist of the instrument (3), it cannot continue to rotate. The maximum opening angle is clearly 50°. By limiting the rotation range, it prevents the opening from being too large and causing unstable clamping.

[0070] The limiting structure protrusion (331), the limiting end (332) and the cross structure (33) of the wrist of the instrument (3) are integrally formed without increasing the volume, perfectly adapting to the spatial constraints of 3mm-level micro instruments.

[0071] The lower sides of the fourth ultrafine rope through hole (321) and the fifth ultrafine rope through hole (322) of the wrist of the device (3) are provided with additive protrusions (323) formed in one step by additive manufacturing (3D printing) technology, which are used to limit the swing angle of the wrist of the device (3).

[0072] The additive protrusion (323) acts as a "physical limiting block" and is integrally formed with the main body of the instrument wrist (3) through 3D printing. Its rigid structure intervenes in the rotation path of the connecting shaft: when the ear plate structure (31) drives the instrument wrist (3) to rotate around the axis, the additive protrusion (323) will contact the arc-shaped ear plate structure (226) of the instrument base (2), forcibly terminating the rotation and limiting the swing angle to the range of ±33°.

[0073] The edge structure of the threading hole of the instrument base (2) is slightly deformed. Through stamping, its edge structure is transformed into an arc, forming a guide slope (224), which allows the ultrafine rope to be inserted with a slightly smaller angle deviation, reducing the stringent requirements for "coaxiality" and improving the threading efficiency.

[0074] Furthermore, plastic deformation can also be achieved using processes such as micro-forging, riveting, spinning, or laser hot deformation to form a smooth transition guide surface.

[0075] Furthermore, the guide slope (224) has an arc radius of 0.9 mm, which provides a smooth transition guide for the ultrafine rope within a certain angle range, reducing wear on the ultrafine rope.

[0076] Furthermore, the permissible angular deviation is ±15°.

[0077] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A 3mm-class miniature tether-driven needle holder for minimally invasive surgery, characterized in that, Includes instrument tubes, instrument bases, instrument wrists, forceps heads, and ultrafine cords; The instrument tube is a hollow TC4 titanium alloy long rod with an outer diameter of 3mm, used to thread ultrafine ropes. The instrument base includes a base connecting part and a bifurcated cavity part. The base connecting part is precisely nested and fitted with the inner diameter of the instrument tube. The head of the bifurcated cavity part extends into a bifurcated arc-shaped ear plate structure. The left and right end faces of the bifurcated cavity part are provided with a first set of ultra-fine rope holes and a second set of ultra-fine rope holes, and the front and rear end faces are provided with a third set of ultra-fine rope holes. The end faces are provided with arc-shaped guide surfaces, and the arc-shaped ear plate structure is provided with a first shaft hole. The wrist of the device includes an ear plate structure, a main body structure and a cross structure. The ear plate structure is a cylinder with a first annular groove with a bevel and an arc around its circumference and a second shaft hole in the center. The main body structure has a fourth and a fifth ultra-fine rope through hole symmetrically arranged on both sides and an additive protrusion on the lower two sides. The cross structure has a protrusion on the upper part, a limiting end on the left and right ends, and a connecting shaft at the front and back. The pliers head includes symmetrical pliers head A and pliers head B. Both pliers head A and pliers head B include a hinge end, a pliers head body and pliers teeth. The hinge end is provided with an annular groove and a third shaft hole, and the pliers teeth are cross-engaged. The ultra-fine rope consists of three sets of six medical-grade 0.3mm stainless steel ropes or 0.2mm tungsten wire ropes, each threaded through a corresponding hole to drive the opening and closing of the forceps head and the rotation of the instrument wrist.

2. The 3mm-class miniature cord-driven needle holder according to claim 1, characterized in that, The edge of the wire-threading hole in the bifurcated cavity of the instrument base is subjected to micro-plastic deformation through stamping, micro-forging, riveting, spinning, or laser thermal deformation processes to form an arc-shaped guide surface, allowing the ultra-fine rope to be inserted with an angle deviation of ±15°.

3. The 3mm-class miniature cord-driven needle holder according to claim 2, characterized in that, The additive protrusion of the wrist of the device is integrally formed with the main structure through selective laser melting (SLM) additive manufacturing technology. When the wrist of the device rotates around the axis, the additive protrusion interferes with the arc-shaped ear plate structure of the device base, limiting the swing angle of the wrist of the device to ±33°, and the symmetry error of the left and right swing angle is ≤1°.

4. The 3mm-class miniature cord-driven needle holder according to claim 3, characterized in that, The protrusion of the cross structure on the wrist of the instrument is used to limit the closing of the pliers. When pliers A and pliers B close to the center to the predetermined position, the protrusion blocks the pliers from continuing to rotate, preventing over-closing.

5. The 3mm-class miniature cord-driven needle holder according to claim 4, characterized in that, The limiting end of the cross structure at the wrist of the instrument is used to limit the opening of the pliers. When pliers A and pliers B are opened, the limiting end restricts the maximum opening angle of the pliers to 50±1°, ensuring that the opening range is within a reasonable range.

6. The 3mm-class miniature cord-driven needle holder according to claim 5, characterized in that, The ultrafine rope includes a first group of ultrafine ropes, a second group of ultrafine ropes, and a third group of ultrafine ropes; The first set of ultra-fine ropes passes through the first set of ultra-fine rope holes and the fourth ultra-fine rope through hole and is inserted into the annular groove of the pliers A, which is used to drive the pliers A to open and close. The second set of ultra-fine ropes passes through the second set of ultra-fine rope holes and the fifth ultra-fine rope through hole and is inserted into the annular groove of the pliers B, which is used to drive the pliers B to open and close. The third set of ultra-fine ropes is wound around the first annular groove of the ear plate structure through the third set of ultra-fine rope holes, and is used to drive the rotation of the instrument wrist.

7. The 3mm-class miniature cord-driven needle holder according to claim 6, characterized in that, The teeth of pliers A and pliers B are positioned one tooth apart, forming a "tooth tip and tooth root cross meshing" structure when closed, which improves clamping stability and biting force.

8. The 3mm-class miniature cord-driven needle holder according to claim 7, characterized in that, The second shaft hole of the wrist of the instrument forms a transition fit with the first shaft hole of the instrument base through the wrist pivot and pivot cap, with a gap of ≤0.01mm, providing a fulcrum for wrist rotation.

9. The 3mm-class miniature cord-driven needle holder according to claim 8, characterized in that, The clamp head A and clamp head B are connected by a hinge shaft. The third shaft hole at the hinge end forms a hinge with the connecting shaft of the cross structure of the instrument wrist, allowing the clamp head to rotate flexibly around the shaft to open and close.

10. The 3mm-class miniature cord-driven needle holder according to claim 9, characterized in that, When the first set of ultra-fine ropes and the second set of ultra-fine ropes are tightened simultaneously, the tension is converted into torque, which drives the clamp heads A and B to close towards the center; when they are relaxed simultaneously, the clamp heads A and B open, and precise positioning is achieved through the protrusions and the limiting end, ensuring operational safety.

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