Tunnel needle and catheter assembly for preventing subcutaneous detachment

Abstract

The utility model relates to a tunnel needle for preventing subcutaneous detachment and a catheter assembly, and belongs to the technical field of tunnel needles. Comprising a needle rod, and the far end of the needle rod extends to be provided with a working head used for puncture guiding; wherein the working head part is of a reducing structure with the surface in smooth transition, and the working head part at least comprises a guide section and a retention section which are connected in sequence in the direction from far to near; the maximum outer diameter of the retention section is larger than the outer diameter of the guide section, and the guide section and the retention section jointly form a fusiform or long-strip oval structure with the smooth surface. Wherein the guide section is used for passively expanding subcutaneous tissue in the puncture process, and the retention section is used for further expanding the subcutaneous tissue and forming anti-slip interference fit when being connected with a catheter. On the premise that the inner wall of the catheter is not damaged, the axial pulling force is effectively resisted, the connection stability is further improved, and the catheter is prevented from slipping when passing through a narrow subcutaneous tunnel.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of tunnel needle, specifically relates to a tunnel needle and catheter assembly for preventing subcutaneous shedding. BACKGROUND

[0002] In clinical medical treatment, for example, when carrying out the implantation operation of peritoneal dialysis catheter, central venous catheter or implantable drug delivery device, a tunnel needle is usually used to establish a subcutaneous tunnel in the patient's subcutaneous tissue, so as to lead the catheter out of the body or bury it in a specific position.

[0003] The existing tunnel needle is usually made of metal, and its structure is mostly straight rod-shaped, with a sharp end or a blunt head at the front end for puncture, and a catheter connected at the rear end or a specific position of the front end. In use, the doctor holds the tunnel needle to puncture the subcutaneous tissue and drive the catheter through the tunnel.

[0004] However, in actual clinical application, the existing straight or simple stepped tunnel needle has the following main problems:

[0005] On the one hand, the head of the existing tunnel needle is usually simple straight or stepped with a sudden change in diameter. In the puncture process, the needle body lacks effective streamline guidance when it enters the subcutaneous tissue, mainly relying on mechanical force to hard press or tear the tissue to advance. This results in a large puncture resistance, and the doctor feels stiff and laborious when operating. At the same time, the large mechanical resistance means that the mechanical damage to the subcutaneous soft tissue is large, which not only increases the risk of bleeding during the operation, but also causes the patient to have a strong pain in the tunnel area after the operation, which is not conducive to wound healing.

[0006] On the other hand, in the process of establishing a tunnel and dragging a catheter through the subcutaneous tissue, a large frictional resistance is generated between the catheter and the subcutaneous tissue. The connection between the existing tunnel needle and the catheter usually relies on the simple friction force of the sleeve. Since there is no effective axial fixation structure, when the tissue is tightly wrapped or the dragging path is long, the catheter is prone to slip off the tunnel needle under the action of reverse resistance. Once the catheter slips off, the doctor often needs to re-puncture or perform complex remedial operations, which not only prolongs the operation time and increases the workload of the doctor, but also may increase the risk of infection of the patient. CONTENT OF THE UTILITY MODEL

[0007] To solve the above technical problems of the prior art, the utility model provides a tunnel needle and catheter assembly for preventing subcutaneous shedding.

[0008] In order to achieve the above purpose, the utility model adopts the technical scheme of:

[0009] Provided is a tunnel needle for preventing subcutaneous shedding, comprising:

[0010] A needle shaft, a working head for puncture guidance is arranged at the distal end of the needle shaft;

[0011] The working head is a variable-diameter structure with smooth surface transition, and the working head comprises at least a guide segment and a retaining segment connected in sequence along the direction from far to near;

[0012] The maximum outer diameter of the retaining segment is greater than the outer diameter of the guide segment, and the guide segment and the retaining segment jointly form a spindle shape or an elongated ellipse shape with smooth surface;

[0013] The guide segment is used for bluntly expanding subcutaneous tissue during puncture, and the retaining segment is used for further expanding subcutaneous tissue and forming an interference fit for preventing slipping when connected with a catheter.

[0014] Preferably, the guide segment and the retaining segment are connected through smooth concave or streamline surface transition, so that the axial cross-sectional profile of the working head is wave-shaped or gourd-shaped.

[0015] Preferably, the proximal end of the retaining segment is inwardly contracted and smoothly connected with the needle rod, and the outer diameter of the needle rod is smaller than the maximum outer diameter of the retaining segment.

[0016] Preferably, the ratio of the maximum outer diameter of the retaining segment to the outer diameter of the guide segment is 1.2-1.5:1.

[0017] Preferably, the distal end of the guide segment is in a hemispherical, conical frustum or circular arc blunt head structure.

[0018] Preferably, the length of the transition region between the guide segment and the retaining segment along the axial direction is greater than 2 times the maximum outer diameter of the retaining segment, so as to form a gradual expansion structure with a gentle slope.

[0019] Preferably, the outer surface of the retaining segment is formed with at least one circumferentially protruding annular ridge, and the axial cross-section of the annular ridge is in a smooth transition circular arc shape, which is used for embedding the inner wall of the catheter to enhance the axial retaining force.

[0020] Preferably, a plurality of annular ridges are continuously arranged on the retaining segment along the axial direction, and a smooth transition groove is formed between adjacent two annular ridges, so that the retaining segment as a whole presents a multi-segment gourd string structure.

[0021] Preferably, the outer diameter of the guide segment is 1.0 mm, and the maximum outer diameter of the retaining segment is 1.33 mm.

[0022] The utility model also provides a catheter assembly, comprising:

[0023] The tunnel needle for preventing subcutaneous shedding according to any one of the above technical solutions;

[0024] A catheter is connected to the retaining section of the tunnel needle for preventing subcutaneous shedding.

[0025] The utility model provides a tunnel needle and catheter assembly for preventing subcutaneous shedding, and the utility model has the beneficial effects of:

[0026] On the one hand, the effective contact area of the working head and the inner wall of the catheter is increased, and the friction is increased; on the other hand, the undulating geometric feature can form a certain degree of embedded cooperation, effectively resisting the axial pulling force without damaging the inner wall of the catheter, further improving the stability of the connection, and preventing the catheter from slipping off when passing through the narrow subcutaneous tunnel. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 One of the front views of the tunnel needle for preventing subcutaneous shedding is provided for the utility model;

[0028] Figure 2 One of the front views of the tunnel needle for preventing subcutaneous shedding is provided for the utility model;

[0029] Figure 3 One of the front views of the tunnel needle for preventing subcutaneous shedding is provided for the utility model;

[0030] Figure 4 The structure schematic diagram of the catheter assembly is provided for the utility model.

[0031] MARKS OF THE DRAWINGS:

[0032] 1, needle stem; 2, working head; 201, guide section; 202, retaining section; 203, annular ridge; 3, catheter. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the utility model.

[0034] Please refer to Figures 1-4 The specific embodiments provided by the utility model are as follows:

[0035] As Figure 1 The embodiment of the utility model provides a tunnel needle for preventing subcutaneous shedding, which mainly consists of a needle stem 1 and a working head 2 arranged at the distal end of the needle stem 1. The needle stem 1 serves as the main part for transmitting the operating thrust; the working head 2 is the core component for performing puncture guidance and connecting the catheter 3.

[0036] In this embodiment, the working head 2 does not adopt the traditional equal-diameter straight cylindrical structure, but a smooth-transition variable-diameter structure. Specifically in terms of structural distribution, along the direction from the distal end to the proximal end (i.e. from the needle tip to the needle shaft 1), the working head 2 at least comprises a guide segment 201 and a retention segment 202 connected in sequence.

[0037] From the geometric aspect, the maximum outer diameter of the retention segment 202 is larger than that of the guide segment 201. The two are connected through a smooth curved surface, so that the guide segment 201 and the retention segment 202 together constitute an overall profile similar to a spindle or an elongated oval shape. This streamlined appearance with a thick middle and thin ends or a thin front end and a raised rear end eliminates the sharp corners or steps present on the surface.

[0038] Based on this, in one aspect, in the process of establishing a subcutaneous tunnel through puncture, the thinner guide segment 201 first enters the human tissue. With its smaller cross-sectional area and smooth surface, the guide segment 201 can easily squeeze into the tissue gap and preliminarily and gently bluntly expand the subcutaneous tissue, avoiding sharp cutting of nerves and blood vessels. Subsequently, as the depth of needle insertion increases, the larger-diameter retention segment 202 naturally follows, using its gradually raised spindle profile to further enlarge the preliminarily opened tissue channel. This gradual expansion from small to large reduces the frictional resistance during puncture advancement, making the operation feel smoother, and also reducing the patient's tissue damage and pain.

[0039] On the other hand, when connecting the catheter 3 for dragging, this structure plays a role in preventing detachment. When one end of the catheter 3 is sleeved on the working head 2, due to the larger outer diameter of the retention segment 202, the catheter 3 wall will be supported from the inside. Using the elasticity of the catheter 3 material itself, the catheter 3 inner wall will tightly wrap around the raised surface of the retention segment 202, forming a tight interference fit. This fit enhances the axial connection force between the catheter 3 and the needle. Therefore, when the doctor drags the catheter 3 through the tight subcutaneous tissue through the tunnel needle, even if it is subjected to a reverse resistance, the catheter 3 is not easy to slip off the working head 2, thereby ensuring the reliability of the catheter placement process.

[0040] In a preferred embodiment, the guide segment 201 and the retention segment 202 are connected through a smooth concave curve or a streamlined curve.

[0041] From the overall appearance, this curved transition makes the working head 2 present a wave-like or calabash-like shape in the axial cross-section.

[0042] Firstly, the transition mode of streamline or concave surface conforms to the principle of fluid mechanics. During the puncture process, when the working head 2 travels in the subcutaneous tissue, the soft tissue can smoothly slip and expand from the thinner guide section 201 to the thicker retention section 202 along the smooth curved surface. Compared with linear transition, this curved surface can more evenly disperse the radial extrusion force on the tissue, eliminate stress concentration points, further reduce the frictional resistance during puncture travel, and make the doctor's operation feel more delicate and smooth.

[0043] Secondly, when the catheter 3 is sleeved thereon, the material of the catheter 3 will deform in response to the undulating curved surface. This non-simple cylindrical contact mode, on the one hand, increases the effective contact area between the working head 2 and the inner wall of the catheter 3, increasing the friction; on the other hand, the undulating geometric characteristics can form a certain degree of embedded cooperation, effectively resisting the axial pulling force without damaging the inner wall of the catheter 3, further improving the stability of the connection and preventing the catheter 3 from slipping off when passing through the narrow subcutaneous tunnel.

[0044] In a preferred embodiment, the proximal end (i.e. the side towards the needle shaft 1) of the retention section 202 presents a gradually inwardly tapered shape and finally realizes a smooth transition connection with the needle shaft 1.

[0045] At the same time, the outer diameter of the needle shaft 1 is strictly limited to be smaller than the maximum outer diameter of the retention section 202. In the process of establishing a subcutaneous tunnel, when it is necessary to connect the catheter 3, the front end of the catheter 3 will be pushed through the maximum diameter of the retention section 202. Since the needle shaft 1 is thin and the proximal end of the retention section 202 is tapered inwardly, after the catheter 3 passes over the raised part of the retention section 202, the tube opening part will be contracted due to the elastic recovery force of the material itself and tightly wrap around the tapered slope of the needle shaft 1 or the retention section 202.

[0046] At this time, the back of the raised part (i.e. the proximal tapered part) of the retention section 202 actually forms a physical blocking structure inside the catheter 3. When the doctor pulls the tunnel needle outward to pull the catheter 3, this raised structure can effectively resist the pulling force in the direction of the catheter 3 falling off, forming a firm mechanical anchor. Even in the case of greater resistance of the subcutaneous tissue, the catheter 3 can be firmly hooked and will not easily slip off the needle shaft 1. At the same time, the smooth connection ensures that this part will not cause unnecessary scraping or cutting damage to the surrounding tissue when necessary (such as separation after completing the catheterization) or during the puncture process.

[0047] In a preferred embodiment, the ratio of the maximum outer diameter of the retention section 202 to the outer diameter of the guide section 201 is set to be in the range of 1.2-1.5:1.

[0048] Firstly, the lower limit of the ratio (1.2:1) is set to ensure sufficient retention effect and expansion allowance. If the ratio is lower than 1.2, the protrusion of the retention section 202 relative to the guide section 201 is too small, which on one hand cannot provide sufficient radial support force when connecting the catheter 3, resulting in insufficient interference fit, and the catheter 3 is easy to slip off; on the other hand, its pre-expansion effect on the subcutaneous tissue is not obvious, and the subsequent catheter 3 entering will still be resisted by a large amount of tissue contraction.

[0049] Secondly, the upper limit of the ratio (1.5:1) is set to control the puncture damage and operation resistance. If the ratio is higher than 1.5, it means that the protrusion of the retention section 202 is too large, making the slope of the transition from the guide section 201 to the retention section 202 steep. This not only significantly increases the pushing resistance during the puncture process, making it difficult for the doctor to operate, but more seriously, it will excessively expand or tear the subcutaneous soft tissue, increasing the patient's pain and postoperative healing difficulty. In addition, the excessive diameter difference may also cause the catheter 3 to be excessively expanded when sleeved and even deformed or torn.

[0050] Therefore, controlling the radial ratio within the preferred range of 1.2-1.5:1 can achieve the best balance: it can not only ensure that the catheter 3 is connected firmly and not easy to fall off, but also minimize the mechanical damage to the tissue, achieving a smooth puncture catheter experience.

[0051] In a preferred embodiment, the outer diameter of the guide section 201 is 1.0 mm, and the maximum outer diameter of the retention section 202 is 1.33 mm.

[0052] In a preferred embodiment, the distal end of the guide section 201 adopts a blunt head structure in the form of a hemisphere, a conical frustum or a circular arc.

[0053] Traditional sharp needle tips mainly rely on cutting action to break through the tissue during puncture, which easily cuts off the fine blood vessels and nerve fibers along the way, resulting in a large amount of intraoperative bleeding and postoperative hematoma. The blunt head structure used in this embodiment mainly produces a blunt separation effect when puncturing and advancing.

[0054] When the blunt head contacts the subcutaneous tissue, it tends to push the tissue fibers, blood vessels and nerves to the sides rather than cutting them directly. This pushing rather than cutting mode greatly reduces the risk of damaging important blood vessels or nerves, and reduces intraoperative bleeding and tissue damage. At the same time, for the patient, the pain caused by blunt puncture is much smaller than that caused by sharp cutting, which is beneficial to improve the recovery speed and comfort after the operation. In addition, the conical frustum or hemispherical end shape can also play a good guiding role, guiding the needle body to travel along the natural direction of the tissue gap, avoiding accidental puncture of the needle body through the skin or deep into the muscle layer.

[0055] As Figure 2As shown, in a preferred embodiment, in order to further enhance the reliability of the connection of the catheter 3 and prevent slippage in extreme stress conditions, at least one circumferential ridge 203 is formed on the outer surface of the retention section 202, and the axial cross-section of the circumferential ridge 203 is in the shape of a smooth transition circular arc.

[0056] When the catheter 3 is sleeved on the retention section 202, due to the elasticity of the material of the catheter 3 (usually silicone or PU), the slightly convex circumferential ridge 203 will locally extrude the inner wall of the catheter 3. On the basis of interference fit, the circumferential ridge 203 will further embed into the soft tissue of the inner wall of the catheter 3, causing local elastic deformation of the inner wall of the catheter 3, forming an embedded mechanical engagement structure.

[0057] When the catheter 3 is subjected to an outward axial tensile force, the circumferential ridge 203 embedded in the inner wall of the catheter 3 will generate a great resistance to prevent it from slipping. At the same time, since the cross-section of the circumferential ridge 203 is in the shape of a smooth transition circular arc, it provides strong grip while avoiding cutting or scratching the inner wall of the catheter 3, ensuring that the catheter 3 remains structurally intact during connection and subsequent separation, and there is no risk of debris or leakage due to damage to the inner wall.

[0058] As shown in the drawings, Figure 3 In a preferred embodiment, a plurality of circumferential ridges 203 are arranged in series along the axial direction of the retention section 202, and the adjacent two circumferential ridges 203 are connected by a smooth transition groove. This alternating arrangement of ridges and grooves makes the retention section 202 have a wave-like structure similar to a sugar-coated skewer or a multi-sectioned skewer in overall appearance.

[0059] Based on this, first of all, each circumferential ridge 203 constitutes an independent blocking node. When the catheter 3 is sleeved thereon, the inner wall of the catheter 3 will deform elastically in multiple places in response to this undulating structure: the tube wall is lifted by the circumferential ridge 203 and then rebounds to fill into the adjacent groove.

[0060] This matching mode has two gains: first, it increases the effective contact area between the catheter 3 and the needle, thereby greatly increasing the static friction; second, when the catheter 3 is subjected to accidental drag force, even if the front end of the tube wall has a slight slip, the subsequent circumferential ridges 203 will immediately play a blocking role, and the catheter 3 material filled in the groove will form a shear-resistant resistance. This cumulative resistance makes it more difficult for the catheter 3 to slip, thereby ensuring that the catheter 3 can always maintain a highly reliable connection state with the tunnel needle in complex surgical environments or long-distance subcutaneous dragging operations, completely eliminating the safety hazards of single-point retention failure.

[0061] As shown in the drawings, Figure 4 The present embodiment also provides a catheter 3 assembly, comprising:

[0062] The tunnel needle for preventing subcutaneous exfoliation as claimed in any one of the preceding embodiments;

[0063] The catheter 3, one end of which is sleeved to the retaining section 202 of the tunnel needle for preventing subcutaneous exfoliation, has all the beneficial effects as described above, which will not be repeated here.

[0064] Although the embodiments of the present application have been shown and described, it should be understood by those ordinary skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A tunneling needle for preventing subcutaneous sloughing, characterized by, Comprising: a needle rod, a working head for puncture guidance is provided at a distal end of the needle rod; wherein the working head is a variable diameter structure with smooth surface transition, the working head at least includes a guide segment and a retaining segment connected in sequence along the direction from distal to proximal; the maximum outer diameter of the retaining segment is greater than the outer diameter of the guide segment, and the guide segment and the retaining segment together constitute a spindle-shaped or long elliptical structure with smooth surface; wherein the guide segment is used to bluntly expand subcutaneous tissue during puncture, and the retaining segment is used to further expand subcutaneous tissue and form an interference fit with the catheter to prevent slipping.

2. The tunneling needle for preventing subcutaneous peeling according to claim 1, wherein The guide segment and the retaining segment are connected by a smooth concave surface or a streamline surface, so that the axial cross-sectional profile of the working head is wave-shaped or gourd-shaped.

3. The tunnel needle for preventing subcutaneous shedding according to claim 1, wherein: the proximal end of the retaining segment is inwardly retracted and smoothly connected with the needle rod, and the outer diameter of the needle rod is smaller than the maximum outer diameter of the retaining segment.

4. The tunnel needle for preventing subcutaneous shedding according to claim 1, wherein: the ratio of the maximum outer diameter of the retaining segment to the outer diameter of the guide segment is 1.2-1.5:

1.

5. The tunnel needle for preventing subcutaneous shedding according to claim 1, wherein: the distal end of the guide segment is a blunt structure in the form of a hemisphere, a conical frustum or a circular arc.

6. The tunnel needle for preventing subcutaneous shedding according to claim 1, wherein: the length of the transition region between the guide segment and the retaining segment in the axial direction is greater than 2 times the maximum outer diameter of the retaining segment, forming a gradual expansion structure in the form of a gentle slope.

7. The tunneling needle for preventing subcutaneous lift-off according to claim 1, wherein An outer surface of the retaining segment is formed with at least one circumferentially protruding annular ridge, the axial cross-section of the annular ridge is a smooth transition circular arc, which is used to embed the inner wall of the catheter to enhance the axial retention force.

8. The tunneling needle for preventing subcutaneous lift-off according to claim 7, characterized by, A plurality of annular ridges are provided on the retaining segment in the axial direction, and a smooth transition groove is formed between adjacent two annular ridges, so that the retaining segment as a whole presents a multi-segment gourd string structure.

9. The tunneling needle for preventing subcutaneous lift-off according to claim 1, wherein The outer diameter of the guide segment is 1.0 mm, and the maximum outer diameter of the retaining segment is 1.33 mm.

10. A catheter assembly comprising: Comprising: the tunnel needle for preventing subcutaneous shedding according to any one of claims 1 to 9; a catheter, one end of which is connected to the retaining segment of the tunnel needle for preventing subcutaneous shedding.

Images