Intubation device for small animal intestinal lymph drainage and manufacturing method

Abstract

This invention relates to a cannulation device and manufacturing method for draining intestinal lymphatic fluid in small animals. The device includes a catheter and a guidewire. The catheter includes an insertion section and a drainage section, the outer and inner diameters of which are smaller than those of the drainage section. The guidewire can be inserted along the catheter, and its outer diameter is smaller than the inner diameter of the insertion section. The insertion tip of the guidewire is blunt and rounded, and the tail end of the guidewire is provided with a handle. By using the cannulation device of this invention, the problems of difficult catheter insertion and significant damage to the mesenteric lymphatic vessels during pretreatment in existing intestinal lymphatic fluid drainage cannulation techniques are solved, reducing the difficulty of surgical operation, shortening the operation time, reducing tissue damage, and improving the success rate of surgery.

Description

Technical Field

[0001] This invention belongs to the field of animal experimental technology in environmental science and environmental toxicology, specifically relating to a cannulation device for draining intestinal lymph fluid in small animals and its manufacturing method. Background Technology

[0002] In the interdisciplinary research field of biomedicine and environmental science, particularly in environmental toxicology, drug toxicology, immunology, pharmacology, and physiology, the mesenteric lymph duct, as a special functional channel connecting the intestine to the systemic circulatory system, undertakes the differentiated transport function of substances absorbed by the intestine. Its transport mechanism and function are becoming a research hotspot of common interest across multiple fields. Unlike the portal venous pathway, the intestinal lymphatic pathway is the core absorption and transport route for lipid-soluble substances (such as lipid-soluble nutrients, drugs, and environmental pollutants). Through this pathway, lipid-soluble substances can bypass the first-pass effect of the liver and directly enter the systemic circulation. The lymphatic transport process directly determines the bioavailability, in vivo distribution, and final effects of these substances. Therefore, obtaining pure and intact intestinal lymph is a key technical foundation for studying the intestinal transport mechanism of lipid-soluble substances and assessing their pharmacokinetics and pharmacological / toxicological effects. Establishing a stable and efficient intestinal lymph drainage model constitutes the core technical cornerstone of basic research and preclinical studies in environmental toxicology and pharmacology.

[0003] Currently, the establishment of intestinal lymphatic drainage models mainly relies on traditional microsurgical methods. This method typically requires meticulous manipulation under an operating microscope. The standard procedure includes: first, exposing and locating the mesenteric lymphatic vessels and their accompanying superior mesenteric artery through an abdominal incision; second, using fine microsurgical instruments under a microscope, carefully and thoroughly dissecting the connective tissue and fat surrounding the mesenteric lymphatic vessels to fully expose a section of lymphatic vessel approximately several millimeters in length. This process requires the operator to possess exceptional microsurgical skills and great patience to avoid damaging the lymphatic vessel wall or its accompanying blood vessels; next, using microsurgical scissors or other sharp tools, creating a tiny V-shaped or oblique incision on the dissected mesenteric lymphatic vessel wall; then, the operator gently lifts the lymphatic vessel wall at the edge of the incision with one micro-forceps while simultaneously holding the tip of a plastic catheter, typically with an outer diameter of 0.6-0.8 mm, with another micro-forceps, attempting to align and insert it parallel to the lymphatic vessel lumen.

[0004] This traditional technique presents a series of significant technical bottlenecks and operational difficulties. First, complete dissection of the connective tissue and fat surrounding the mesenteric lymphatic vessels is a necessary prerequisite for successful cannulation. However, this step requires extreme caution, is highly challenging, and time-consuming, as the lymphatic vessel walls are fragile, and excessive dissection can easily cause tearing, leading to cannulation failure. Second, creating an incision in the mesenteric lymphatic vessel wall is a critical and high-risk step. The size and angle of the incision must be precisely controlled; an excessively large incision or angle may cause complete rupture of the lymphatic vessel, while an excessively small incision or angle will prevent catheter insertion. Third, when using forceps to lift the mesenteric lymphatic vessel wall to assist insertion, the clamping force of the forceps tip on the vessel wall is difficult to control precisely, easily causing injury, compression, or even secondary tearing of the vessel wall. Fourth, and most importantly, lies the contradiction between the flexible nature of the catheter and the requirements of micromanipulation. Because the catheter is soft and the lymphatic vessels are thin, when the operator grasps and advances a very short section of the catheter, the tip is prone to bending, deformation, lateral deviation, or upward tilting, making precise placement into the lymphatic lumen difficult. The procedure requires repeated adjustments to the gripping force and insertion angle, which not only significantly prolongs the time of each insertion surgery and increases the risk of anesthesia and physiological fluctuations in experimental animals, but also further exacerbates the risk of lymphatic vessel damage due to repeated manipulation, ultimately leading to a low overall surgical success rate. These limitations restrict the efficiency and scale of related research and raise concerns about the welfare of laboratory animals.

[0005] Therefore, there is an urgent need to develop a new intestinal lymphatic drainage device that can simplify the operation steps, shorten the operation time, reduce the technical difficulty and improve the success rate. Summary of the Invention

[0006] To address at least one of the problems in the prior art, the present invention aims to provide a cannulation device and manufacturing method for draining intestinal lymphatic fluid in small animals. This invention solves the problems of difficulty in catheter insertion and significant damage to mesenteric lymphatic vessels during pretreatment in existing intestinal lymphatic fluid drainage cannulation techniques. By using this device, the difficulty of surgical operation is reduced, the operation time is shortened, tissue damage is reduced, and the success rate of surgery is improved.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A cannulation device for draining intestinal lymph fluid in small animals, comprising: The catheter includes an insertion section and a drainage section, wherein the outer diameter and inner diameter of the insertion section are both smaller than the outer diameter and inner diameter of the drainage section; A guidewire is inserted along the catheter, the outer diameter of the guidewire being smaller than the inner diameter of the insertion section; the insertion tip of the guidewire is blunt and rounded, and the tail end of the guidewire is provided with a handle.

[0008] Preferably, the outer wall of the catheter is provided with multiple fixing buckles at intervals.

[0009] Preferably, the fixing buckle includes a first fixing buckle, a second fixing buckle, a third fixing buckle, and a fourth fixing buckle, the length of the first fixing buckle, the second fixing buckle, the third fixing buckle, and the fourth fixing buckle are all 0.2cm; the distances of the first fixing buckle, the second fixing buckle, the third fixing buckle, and the fourth fixing buckle to the end point of the insertion segment are 0.8cm, 3cm, 5.5cm, and 7cm, respectively. The first fixing buckle is used to fix the catheter to the mesenteric lymphatic vessel, and the second fixing buckle, the third fixing buckle, and the fourth fixing buckle are used to suture and fix the catheter to the abdominal wall in segments and at multiple points.

[0010] Preferably, the fixing buckle is a short tube, which is sleeved on the outer wall of the conduit.

[0011] Preferably, the outer wall of the catheter is provided with a pressure-resistant protective tube, the pressure-resistant protective tube is 0.5cm long and the distance between it and the end point of the insertion section is 1.5cm.

[0012] Preferably, the end of the guidewire is wound around the handle, and the guidewire and the handle form a T-shaped structure.

[0013] Preferably, after the guidewire is inserted into the catheter, the insertion tip of the guidewire protrudes 1 mm beyond the catheter, forming a composite catheter tip guided by the insertion tip of the guidewire.

[0014] A method for manufacturing a catheter device for draining intestinal lymph fluid in small animals, the manufacturing of which includes the following steps: Take a plastic catheter and mark a 1cm section on it with a marker. This section will be used as the insertion section. The marked section is subjected to controlled heating. When the catheter is heated, the marked section is slowly stretched to a length of 2cm, reducing its outer and inner diameters. The stretched section is then cut off, leaving a 1cm section at the end, thus completing the fabrication of the insertion section. The section adjacent to the insertion section is the drainage section. Four short tubes, each 0.2 cm long, are cut as fixing buckles. The four fixing buckles are fixed at preset positions 0.8 cm, 3 cm, 5.5 cm, and 7 cm away from the end of the insertion section of the conduit, respectively. Cut a silicone tube to a length of 0.5cm, and fit and fix the silicone tube 1.5cm away from the insertion end of the conduit to complete the fabrication of the pressure-resistant protective tube.

[0015] Preferably, the fabrication of the guidewire includes the following steps: A section of rigid solid metal wire of a predetermined length is cut as the built-in guide wire, and the entire section of guide wire is polished with fine sandpaper. The tail end of the guidewire is heated to soften it, and then tightly wound around an aluminum rod, which serves as the handle of the guidewire. The handle and the guide wire are fixed together by crossing and wrapping copper wire around each other, so that the two form a T-shaped structure.

[0016] Preferably, during the polishing process of the guidewire, the insertion tip of the guidewire is ground into a smooth, blunt round shape.

[0017] The present invention has the following advantages due to the adoption of the above technical solutions: 1. The catheterization device and manufacturing method for draining intestinal lymphatic fluid in small animals provided by the present invention have an optimized design for the catheter insertion end, which has a smaller diameter, thinner wall, and better fit with the guidewire. Combined with the optimized blunt dissection and guided insertion method, the mesenteric lymphatic cannulation operation is fundamentally simplified. The built-in guidewire provides rigid guidance for the soft catheter during insertion, solving the core problem of easy bending of the catheter tip and difficulty in accurate insertion in traditional methods. This greatly reduces the dependence on the operator's microsurgical skills, allowing even novices to master the technique more quickly.

[0018] 2. The catheterization device and manufacturing method for draining intestinal lymph fluid in small animals provided by the present invention have an inner diameter of the catheter insertion section that is close to the outer diameter of the guide wire. After the insertion section is thinned, the tube wall is thinner, which effectively reduces the resistance brought by the mesenteric lymphatic vessel wall during catheterization.

[0019] 3. The catheterization device and manufacturing method for draining intestinal lymph fluid in small animals provided by the present invention, with optimized blunt puncture technique, avoids excessive sharp dissection of the mesenteric lymphatic vessel wall, reducing the risk of vessel wall damage and bleeding.

[0020] 4. The catheterization device and manufacturing method for draining intestinal lymph fluid in small animals provided by the present invention have a special anti-pressure protective tube that protects the catheter from being damaged by the needle holder during the advancement process, ensuring unobstructed lumen.

[0021] 5. The catheterization device and manufacturing method for small animal intestinal lymphatic drainage provided by this invention, with its multiple fixing buckle design and different spacing, effectively prevents postoperative catheter displacement or dislodgement, ensuring the long-term stability of lymphatic drainage. These improvements work synergistically to effectively increase the success rate of surgery, enhance the repeatability and stability of the technique, thereby strongly promoting the efficiency and scale of related research and meeting the ethical requirements of laboratory animal welfare. Although this device is specifically implemented on rats, it can be adapted to other small laboratory animals such as mice for lymphatic and blood drainage by adjusting the specifications of the catheter and guidewire, thus having a wide range of applications. Attached Figure Description

[0022] Figure 1This is a schematic diagram of the cannulation device for draining intestinal lymph fluid in small animals provided in Embodiment 1 of the present invention.

[0023] Figure 2 This is a schematic diagram of the catheter provided in this embodiment of the present invention.

[0024] Figure 3 This is a schematic diagram of the AA cross-section of the catheter insertion segment provided in this embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram of the BB cross-section of the catheter drainage section provided in this embodiment of the present invention.

[0026] Figure 5 This is a schematic diagram of the guidewire provided in this embodiment of the present invention.

[0027] Figure 6 This is a schematic diagram of the front end structure of the cannulation device for draining intestinal lymph fluid in small animals provided in this embodiment of the present invention.

[0028] Figure 7 This is a flowchart of the method for manufacturing a catheter for draining intestinal lymph fluid in small animals, as provided in Embodiment 2 of the present invention.

[0029] Figure 8 This is a flowchart of the method for fabricating the guide wire of the cannulation device for draining intestinal lymph fluid in small animals, as provided in Embodiment 2 of the present invention.

[0030] Marked in the attached diagram: 1 is the catheter, 101 is the insertion section, 102 is the drainage section, 2 is the guidewire, 3 is the handle, 4 is the fixing buckle, 401 is the first fixing buckle, 402 is the second fixing buckle, 403 is the third fixing buckle, 404 is the fourth fixing buckle, and 5 is the pressure-resistant protective tube. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0032] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the system or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0033] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "assembly," "setup," and "connection" 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.

[0034] This invention provides a cannulation device and manufacturing method for draining intestinal lymph fluid in small animals, which solves the problems of difficult catheter insertion and large damage to mesenteric lymphatic vessels in existing intestinal lymph fluid drainage cannulation techniques. By using this device, the difficulty of surgical operation is reduced, the operation time is shortened, tissue damage is reduced, and the success rate of surgery is improved.

[0035] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0036] Example 1 Please refer to Figures 1 to 6 This embodiment provides a cannulation device for draining intestinal lymph fluid in small animals, comprising a catheter 1 and a guidewire 2: The catheter 1 includes an insertion section 101 and a drainage section 102, the outer diameter and inner diameter of the insertion section 102 being smaller than the outer diameter and inner diameter of the drainage section 102; The guidewire 2 can be inserted along the catheter 1. The outer diameter of the guidewire 2 is smaller than the inner diameter of the insertion section 101. The insertion head of the guidewire 2 is blunt and rounded, and the tail end of the guidewire 2 is provided with a handle 3.

[0037] Specifically, catheter 1 is a flexible plastic tube, comprising an insertion section 101 and a drainage section 102. The insertion section 101 is used for insertion into the mesenteric lymphatic vessels, and the drainage section 102 is used for lymphatic drainage. Notably, catheter 1 is a complete continuous tube; the inner diameter of the insertion section 101 is slightly larger than the outer diameter of the guidewire 2, allowing for better fit between the two. Furthermore, the insertion section 101 is thinned, with an outer diameter smaller than the drainage section 102, effectively reducing the resistance from the tube wall when the guidewire tip punctures the mesenteric lymphatic vessels and is inserted into catheter 1. Catheter 1 is provided with multiple fixing buckles 4 at intervals along its length to secure catheter 1 within the mesenteric lymphatic vessels and abdominal cavity after insertion, preventing displacement within the abdominal cavity. Specifically, the catheter 1 is provided with a pressure-resistant protective tube 5 near the insertion end. This pressure-resistant protective tube is made of elastic materials such as silicone and can be used as a dedicated clamping point for the microsurgical needle holder. When inserting the catheter, the operator clamps the pressure-resistant protective tube 5 to push the catheter 1 forward, avoiding the needle holder from directly clamping the catheter 1 and causing damage or deformation.

[0038] Guidewire 2 is a rigid guidewire used in conjunction with catheter 1. After guidewire 2 is inserted into the lumen of catheter 1, its tip protrudes approximately 1 mm beyond the insertion end of the catheter, forming a composite catheter tip with sufficient axial rigidity, guided by a rigid, blunt, rounded tip. During insertion, guidewire 2 provides internal support for the flexible catheter while guiding the catheter tip to maintain a straight path, ensuring smooth insertion into the lumen. Its rigid, blunt, rounded tip can pierce the wall of the mesenteric lymphatic vessels without fully dissecting (or without dissecting) the connective tissue and fat surrounding the mesenteric lymphatic vessels. Guidewire 2 and handle 3 are designed with a T-shaped structure for easy gripping and rotational retraction of guidewire 2 by the operator.

[0039] In this embodiment, the outer wall of the catheter 1 is provided with multiple fixing buckles 4 at intervals.

[0040] Specifically, the fixing buckle 4 includes a first fixing buckle 401, a second fixing buckle 402, a third fixing buckle 403, and a fourth fixing buckle 404. The lengths of the first fixing buckle 401, the second fixing buckle 402, the third fixing buckle 403, and the fourth fixing buckle 404 are all 0.2 cm. The distances between the first fixing buckle 401, the second fixing buckle 402, the third fixing buckle 403, and the fourth fixing buckle 404 and the endpoint of the insertion segment 101 are 0.8 cm, 3 cm, 5.5 cm, and 7 cm, respectively. The first fixing buckle 401 is used to fix the catheter to the wall of the mesenteric lymphatic vessel. The second fixing buckle 402, the third fixing buckle 403, and the fourth fixing buckle 404 are used to suture and fix the catheter 1 in segments and at multiple points in the abdominal cavity.

[0041] In this embodiment, the fixing buckle 4 is a short tube that is sleeved on the outer wall of the conduit 1.

[0042] In this embodiment, the outer wall of the catheter 1 is provided with a pressure-resistant protective tube 5, which is 0.5cm long and 1.5cm away from the end point of the insertion section 101.

[0043] In this embodiment, the tail end of the guidewire 2 is wrapped around the handle 3, and the guidewire 2 and the handle 3 form a T-shaped structure.

[0044] In this embodiment, after the guidewire 2 is inserted into the catheter 1, the insertion tip of the guidewire 1 protrudes 1 mm from the catheter, forming a composite catheter tip guided by the insertion tip of the guidewire 2.

[0045] Example 2 Please refer to the reference. Figure 7 The method for manufacturing a catheter device for draining intestinal lymph fluid in small animals provided in this embodiment includes the following steps in the fabrication of the catheter 1: S01. Take a plastic catheter and mark a 1cm long area on the catheter with a marker. This area will be made into the insertion section 101. Perform controlled heating on the marked area. When the catheter is heated, the marked area of ​​the catheter is slowly stretched to a length of 2cm, reducing its outer and inner diameters. Cut off the stretched area, leaving a 1cm length at the end, to complete the fabrication of the insertion section 101 of the catheter. The drainage section 102 is adjacent to the insertion section 101. S02. Cut four short tubes with a length of 0.2cm as fixing buckles 4, and fix the four fixing buckles 4 at preset positions 0.8cm, 3cm, 5.5cm and 7cm away from the end of the insertion section of the tube, respectively. S03. Cut a silicone tube with a length of 0.5cm, put the silicone tube on and fix it 1.5cm away from the end of the insertion section of the conduit 1 to complete the fabrication of the anti-pressure protective tube.

[0046] In the specific fabrication process of catheter 1, firstly, a flexible plastic catheter with an inner diameter of 0.42 mm and an outer diameter of 0.69 mm is prepared. A 1 cm long area is marked on the catheter using a marker; this area will be used as the insertion segment 101. Subsequently, the marked segment is subjected to controlled heating, during which the catheter segment is slowly stretched to approximately 2 cm in length. This heating and stretching process thins the wall of the catheter segment, altering its mechanical properties and increasing its flexibility and compliance, facilitating its subsequent smooth entry into the delicate mesenteric lymphatic vessels. At the center of the stretched segment, a blade is used to cut it at the corresponding catheter location, ensuring a smooth, burr-free, or deformed cut surface. Thus, the catheter insertion segment 101, approximately 1.0 cm long, with thinned walls and good compliance, is completed. The outer diameter of the insertion segment 101 is 0.52 mm, and the inner diameter is 0.32 mm.

[0047] Starting from the initial end of the insertion segment 101, measure a 15cm long section of the catheter and cut it with a blade to obtain the complete catheter body length. The catheter 1 consists of a 1cm insertion segment 101 for mesenteric lymphatic vessel insertion and a subsequent 14cm drainage segment 102 for intestinal lymphatic drainage. To ensure long-term stable fixation of the catheter 1 within the small animal, a fixation structure needs to be prepared and installed. Take another catheter with an outer diameter of 1.02mm and an inner diameter of 0.61mm, and cut four short sections approximately 0.2cm long as fixing clips 4. Securely fix these four clips 4 at predetermined positions 0.8cm, 3cm, 5.5cm, and 7cm from the end of the insertion segment. The first fixing buckle 401, located 0.8 cm from the end of the insertion segment, is specifically used to fix the catheter 1 to the wall of the mesenteric lymphatic vessel. The remaining fixing buckles, located at 3 cm, 5.5 cm, and 7 cm, are used to suture and fix the catheter 1 in segments and at multiple points within the abdominal cavity, thereby effectively preventing the catheter from shifting, twisting, or accidentally dislodging within the abdominal cavity due to animal activity or visceral peristalsis. The specific position of the fixing buckles 4 can also be adaptively adjusted according to individual anatomical differences in experimental animals (such as rats), but the core layout principle is to ensure that the catheter 1 can form a tension-free "C"-shaped course within the abdominal cavity, avoiding sharp bends or traction.

[0048] In addition, to protect catheter 1 from being crushed or damaged by the jaws of the microsurgical needle holder during insertion, a dedicated pressure-resistant sheath needs to be fabricated. Take a section of silicone tubing with an outer diameter of 2.0 mm and an inner diameter of 0.50 mm, and cut it to a length of 0.5 cm. Tightly fit and fix this silicone tubing section 1.5 cm from the end of the catheter insertion section. This silicone sheath is soft and elastic, capable of dispersing the clamping force applied by the needle holder, providing the operator with a safe and reliable point of force application. This effectively prevents the catheter body (especially its thin-walled insertion section) from being indented, damaged, or blocked due to mechanical pressure when pushing the catheter. Finally, install and fix all the aforementioned fixing clips 4 and pressure-resistant sheath 5 to catheter 1 according to the set positions, thus completing the fabrication of the dedicated catheter.

[0049] Please refer to the reference. Figure 8 The fabrication of guidewire 2 includes the following steps: S04. Cut a section of hard solid metal wire of a set length as the built-in guide wire 2, and polish the entire section of guide wire 2 with fine sandpaper. S05. Heat the tail end of the guidewire 2 to soften it, and then tightly wrap it around the aluminum rod. The aluminum rod serves as the handle 3 of the guidewire 2. S06. Use copper wire to cross and wrap around the fixing point of the handle 3 and the guide wire 2 to fix them again, so that the two form a T-shaped structure.

[0050] In this example, during the polishing process of guidewire 2, the insertion tip of guidewire 2 is ground into a smooth, blunt round shape.

[0051] In the fabrication of guidewire 2, a section of solid metal wire approximately 20cm long and 0.3mm in diameter is cut as the internal guidewire 2. The entire guidewire is thoroughly polished with fine sandpaper to remove any burrs or rough spots, ensuring a smooth surface and reducing frictional resistance with the inner wall of catheter 1. The tail end of guidewire 2 requires special treatment for easy gripping and force application. The tail end is heated over an alcohol lamp flame to soften it locally, and then quickly and tightly wound around a 2cm long, 1.5mm diameter aluminum rod, which serves as the handle 3. Copper wire is used to cross and secure the handle, forming a stable T-shaped handle structure. A 16cm section of guidewire is cut, with its tip (insertion end) serving as the guide portion into the lumen. This tip is carefully polished into a smooth, blunt round shape using a fine grinding wheel or whetstone. This blunt rounded tip design minimizes the risk of puncturing or damaging the mesenteric lymphatic vessel wall during insertion. Thus, a special guidewire 2 with a blunt, rounded front end, a T-shaped handle at the rear end, and sufficient rigidity and ease of operation has been manufactured.

[0052] Example 3 In this embodiment, the cannulation device for draining intestinal lymph fluid in small animals is used as an experimental subject by selecting healthy adult rats weighing 250g to 300g. The specific steps include: Step 1: Preoperative assembly and pretreatment of the intubation device; All catheters are made of medical-grade materials. Before the experiment begins, the catheter 1 and T-shaped guidewire 2 fabricated in Example 2 must be sterilized to ensure the aseptic requirements of the procedure. After sterilization, to prevent potential thrombosis on the surfaces of catheter 1 and guidewire 2 within the body, a layer of heparin sodium anticoagulant coating is applied to their surfaces. Specifically, heparin sodium solution is injected into the lumen of catheter 1 to fully wet the inner wall, while simultaneously coating the surface of guidewire 2, and then allowed to air dry for later use.

[0053] Assembly before surgical experiment: Slowly and steadily insert the T-shaped guidewire 2 into the lumen of the prepared catheter 1 until the blunt rounded tip of the guidewire 2 protrudes about 1 mm from the insertion end of the catheter, forming a composite cannula head guided by the tip of the rigid guidewire. Place the assembled cannula device properly on the sterile operating table for easy access at any time.

[0054] The second step is the preoperative preparation of experimental animals and the exposure of the surgical area. Rats were fasted for 12 hours prior to surgery (with free access to water) to reduce food residue and contents in the gastrointestinal tract, thus providing a clearer surgical field after laparotomy. 30-60 minutes before surgery, rats were administered a dose of fat emulsion via gavage. The fat emulsion significantly promoted the production and flow of intestinal lymph fluid, causing the mesenteric lymphatic vessels to appear distinctly milky white due to the filling of chyle, contrasting sharply with the surrounding red arteries, facilitating intraoperative identification of the mesenteric lymphatic vessels and localization of the surgical area. Subsequently, the surgical site (e.g., abdomen) was shaved, and the rats were given analgesia and general anesthesia. The anesthetized rats were securely fixed in a supine position on a temperature-controlled operating table to maintain their body temperature. The abdominal surgical area was alternately disinfected with povidone-iodine and 75% alcohol, then covered with a sterile surgical drape with a central opening to establish a sterile surgical field. The surgical approach was chosen approximately 1 cm below the xiphoid process, with a longitudinal midline incision of about 3-4 cm along the linea alba. The skin, subcutaneous tissue, and linea alba were incised layer by layer to enter the peritoneal cavity. Using sterile gauze soaked in warm saline, the stomach, intestines, and other abdominal organs were gently pushed towards the left ventral side of the rat's body, fully exposing the target surgical area—the mesenteric root region near the confluence of the left renal vein and inferior vena cava. In this area, the operator could clearly observe the milky-white mesenteric lymphatic vessels running parallel to the pulsating, bright red superior mesenteric artery.

[0055] Step 3: Blunt dissection and ligation of the mesenteric lymphatic vessels; Adjust the surgical microscope to the appropriate magnification to obtain a detailed operating field. First, gently dissect the connective tissue and fat surrounding the mesenteric lymphatic vessels using fine microforceps. The separation of the mesenteric lymphatic vessels and the superior mesenteric artery employs a blunt dissection technique: the operator carefully observes the natural anatomical gap between the milky-white mesenteric lymphatic vessels and their accompanying bright red superior mesenteric artery. Using a blunt-tipped, curved microforceps, carefully insert it into this gap from below (the bottom) of the mesenteric lymphatic vessels. Then, by continuously and gently opening and closing the arms of the forceps, the blunt forceps tip is used to perform a "grinding" separation at the junction between the mesenteric lymphatic vessels and the superior mesenteric artery. This process relies primarily on the gentle pressure generated by the opening and closing of the instruments to separate the tissues, rather than sharp cutting. After obtaining a free segment of mesenteric lymphatic vessel through blunt dissection, a medical suture is passed underneath the freed mesenteric lymphatic vessel and ligated at the distal end (i.e., the distal end) where the lymph fluid flows. This ligation has a dual purpose: first, to block the continued flow of lymph fluid in that direction; and second, to allow the lymphatic vessel between the ligation point and the intended insertion point to further fill and expand due to fluid accumulation, moderately increasing the intraluminal pressure and making the vessel wall more rigid, thus creating favorable conditions for subsequent catheter insertion.

[0056] Step 4: Insertion of catheter 1 with guidewire 2 as support; The insertion procedure is the core step: The operator first uses a curved forceps to gently lift and support the mesenteric lymphatic vessel below the ligation line, keeping the target lymphatic segment straight and under moderate tension to facilitate alignment of the insertion device. Then, the operator uses micro-forceps in their left hand to lift the connective tissue surrounding the mesenteric lymphatic vessel to further expand its diameter, while using a micro-needle holder in their right hand to hold the silicone pressure-resistant sheath 5 on the insertion device. The assembled guidewire 2 is positioned so that approximately 1 mm of the composite insertion tip protrudes, facing the direction of lymphatic outflow, and is aligned at a slight angle of approximately 15º with the slightly swollen area near the ligation point. The operator applies steady force, using the axial thrust transmitted by the guidewire, to slowly push the insertion end of the catheter into the lumen of the mesenteric lymphatic vessel. After insertion, the catheter 1 is temporarily and simply fixed to the mesenteric lymphatic vessel near the insertion point to prevent slippage. The operator then pinches the "T"-shaped handle 3 at the end of the guidewire with their fingers and retracts the guidewire about 1-2 cm towards the end of the catheter by rotating it (rather than pulling it directly). At this time, as the tip of the guidewire 2 retracts, the temporary obstruction to the lumen is released, and milky white lymph fluid is observed flowing into the catheter. This phenomenon indicates that the drainage channel has been initially established.

[0057] Step 5: Final fixation of catheter 1 and safe removal of guidewire 2: After confirming that the lymph fluid is flowing smoothly into catheter 1, catheter 1 is further secured. Using medical tissue adhesive (such as 3M tissue adhesive), apply a dotted application around the first fixing buckle 401 on catheter 1, approximately 0.8 cm from the insertion end. Simultaneously, use the long end of the suture left during the initial ligation of the mesenteric lymphatic vessel, wrap it around the fixing buckle and tie a knot. Through the double reinforcement of tissue adhesive and suture, catheter 1 is firmly fixed to the mesenteric lymphatic vessel, ensuring that the insertion position will not move during subsequent procedures. After securing, the operator should stabilize the drainage section 102 of the catheter, which has been withdrawn from the body, with one hand, and with the other hand, hold the handle 3 again, continuing to slowly and evenly withdraw the entire guidewire 2 completely from the catheter lumen using a smooth rotating motion. After the guidewire 2 is completely withdrawn, immediately observe the drainage section 102 of the catheter to confirm that the milky white lymph fluid is flowing out continuously and smoothly. This is a key indicator for judging the final success of the insertion and the patency of the drainage tube.

[0058] Step 6: Planning the intraperitoneal route of the catheter and closing the abdomen: The catheter 1 within the abdominal cavity is positioned and shaped into a "C" shape to conform to the anatomical form of the right posterolateral abdominal wall and adhere closely to the medial abdominal wall. Then, using pre-installed second, third, and fourth fixation buckles 402, 403, and 404 on catheter 1, each buckle is sequentially sutured and fixed to the medial abdominal wall with fine sutures, achieving multi-point, segmented fixation of the catheter within the abdominal cavity. This systematic fixation method enhances the stability of catheter 1, effectively resisting the forces generated by postoperative animal awakening, activity, or intestinal peristalsis, preventing catheter 1 from shifting, twisting, or dislodging from the mesenteric lymphatic vessels. Finally, the sterile gauze placed in the abdominal cavity during the surgery is removed, and displaced organs such as the stomach and intestines are gently repositioned to their normal anatomical positions. The peritoneum, muscle layer, and skin are sutured layer by layer, and the abdominal incision is closed, completing the entire surgical procedure.

[0059] Specifically, a simplified lymphatic fluid collection procedure for anesthetized rats is provided. This method directly omits the third step (blunt dissection and ligation of mesenteric lymphatic vessels) and the sixth step (planning the intraperitoneal course of the catheter) in the above procedure. For rats with well-filled lymphatic vessels, the procedure can proceed directly from the second step to the fourth step, i.e., inserting the catheter 1 into the lymphatic vessel lumen under the support of guidewire 2. After insertion, the catheter is fixed to the lymphatic vessel only with tissue glue; subsequently, using microsurgical instruments (such as microforceps), the lumen is directly transcribed at the distal end of the intestinal lymphatic vessel (towards the rat's right kidney) to block lymphatic flow, and the transcribed section is sealed with tissue glue, with the sealing standard being the absence of white lymphatic fluid leakage. It should be noted that the operation of directly transing the distal end of the lymphatic vessel can be flexibly adjusted according to the experimental purpose: if it is necessary to prevent lymphatic fluid from entering the systemic circulation, this step is necessary; if it is only for collecting lymphatic fluid, it can be omitted. This improved method eliminates the need to dissect the connective tissue and fat surrounding the intestinal lymphatic vessels, as well as the need to separate the mesenteric lymphatic vessels and superior mesenteric artery. It also avoids the need for intraperitoneal catheter planning and fixation (step six). This method is simpler to operate and has significant practical value and application for rapidly obtaining rat intestinal lymph fluid or conducting related research under anesthesia.

[0060] Through the above implementation scheme, this embodiment provides a detailed and repeatable method for using an intestinal lymphatic drainage catheterization device. This device, by preparing a specialized catheter with a special insertion section 101, a pressure-resistant sheath 5, and multi-point fixing buckles 4, combined with a rigid guidewire 2 with a blunt, rounded tip and a T-shaped handle 3 at the tail end, fundamentally solves the problems of soft catheters that are difficult to insert and easily damaged instruments in traditional techniques. Combined with optimized steps such as preoperative fat emulsion filling of the mesenteric lymphatic vessels, intraoperative avoidance of complete (or even non-exfoliation) of the connective tissue and fat surrounding the mesenteric lymphatic vessels, and precise insertion under guidewire support, the device provided in this embodiment systematically reduces the technical threshold of surgical operations and the reliance on operator experience, significantly shortens surgical time, improves the success rate of catheterization, and provides a reliable and convenient technical platform for related research.

[0061] 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 of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cannulation device for draining intestinal lymph fluid in small animals, characterized in that, include: The catheter includes an insertion section and a drainage section, wherein the outer diameter and inner diameter of the insertion section are both smaller than the outer diameter and inner diameter of the drainage section; A guidewire is inserted along the catheter, the outer diameter of the guidewire being smaller than the inner diameter of the insertion section; the insertion tip of the guidewire is blunt and rounded, and the tail end of the guidewire is provided with a handle.

2. The cannulation device for draining intestinal lymph fluid in small animals according to claim 1, characterized in that, The outer wall of the catheter is provided with multiple fixing buckles at intervals.

3. The cannulation device for draining intestinal lymph fluid in small animals according to claim 2, characterized in that, The fixing buckle includes a first fixing buckle, a second fixing buckle, a third fixing buckle, and a fourth fixing buckle. The lengths of the first fixing buckle, the second fixing buckle, the third fixing buckle, and the fourth fixing buckle are all 0.2 cm. The distances of the first fixing buckle, the second fixing buckle, the third fixing buckle, and the fourth fixing buckle from the endpoint of the insertion segment are 0.8 cm, 3 cm, 5.5 cm, and 7 cm, respectively. The first fixing buckle is used to fix the catheter to the mesenteric lymphatic vessels, and the second fixing buckle, the third fixing buckle, and the fourth fixing buckle are used to suture and fix the catheter to the abdominal wall in segments and at multiple points.

4. The cannulation device for draining intestinal lymph fluid in small animals according to claim 2, characterized in that, The fixing buckle is a short tube that is sleeved on the outer wall of the conduit.

5. The cannulation device for draining intestinal lymph fluid in small animals according to claim 1, characterized in that, The outer wall of the catheter is provided with a pressure-resistant protective tube, which is 0.5 cm long and 1.5 cm away from the end point of the insertion section.

6. The cannulation device for draining intestinal lymph fluid in small animals according to claim 1, characterized in that, The end of the guidewire is wrapped around the handle, and the guidewire and the handle form a T-shaped structure.

7. The cannulation device for draining intestinal lymph fluid in small animals according to claim 1, characterized in that, After the guidewire is inserted into the catheter, the insertion tip of the guidewire protrudes 1 mm beyond the catheter, forming a composite catheter tip guided by the insertion tip of the guidewire.

8. A method for manufacturing a cannulation device for draining intestinal lymph fluid in small animals, characterized in that, The fabrication of the catheter includes the following steps: Take a plastic catheter and mark a 1cm section on it with a marker. This section will be used as the insertion section. The marked section is subjected to controlled heating. When the catheter is heated, the marked section is slowly stretched to a length of 2cm, reducing its outer and inner diameters. The stretched section is then cut off, leaving a 1cm section at the end, thus completing the fabrication of the insertion section. The section adjacent to the insertion section is the drainage section. Four short tubes, each 0.2 cm long, are cut as fixing buckles. The four fixing buckles are fixed at preset positions 0.8 cm, 3 cm, 5.5 cm, and 7 cm away from the end of the insertion section of the conduit, respectively. Cut a silicone tube to a length of 0.5cm, and fit and fix the silicone tube 1.5cm away from the insertion end of the conduit to complete the fabrication of the pressure-resistant protective tube.

9. The method for manufacturing the cannulation device for draining intestinal lymph fluid in small animals according to claim 8, characterized in that, The fabrication of the guidewire includes the following steps: A section of rigid solid metal wire of a predetermined length is cut as the built-in guide wire, and the entire section of guide wire is polished with fine sandpaper. The tail end of the guidewire is heated to soften it, and then tightly wound around an aluminum rod, which serves as the handle of the guidewire. The handle and the guide wire are fixed together by crossing and wrapping copper wire around each other, so that the two form a T-shaped structure.

10. The method for manufacturing the cannulation device for draining intestinal lymph fluid in small animals according to claim 9, characterized in that, During the polishing process of the guidewire, the insertion tip of the guidewire is ground into a smooth, blunt round shape.

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