Internal drainage end-by-end reducer pipe

Abstract

The invention belongs to the field of biomedical materials, and particularly relates to an inner drainage end-by-end reducer tube based on the electrostatic spinning technology and a preparation method thereof.The inner drainage end-by-end reducer tube comprises an end-by-end reducing drainage tube, the whole drainage tube is of a hollow conical tubular structure, and the surface of the drainage tube is provided with regularly-arranged thread structures; the invention further provides a preparation method of the inner drainage end-by-end reducer pipe. The defects of existing internal drainage are overcome, and the natural anatomical form of the pancreatic duct is complied with by means of the drainage tube with the diameter changed end by end; the drainage tube is provided with a surface thread structure, and by matching with the swelling characteristic of a biodegradable material, the friction force between the drainage tube and the pancreatic duct wall is increased, and the probability of displacement of the drainage tube due to intestinal tract movement or pancreatic juice scouring is reduced.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials, specifically relating to an internally draining, end-to-end variable diameter tube based on electrospinning technology and its preparation method. Background Technology

[0002] Pancreaticoduodenectomy is the standard surgical procedure for treating tumors of the pancreatic head and periampullary region. It is also one of the most challenging and complex surgical procedures, with pancreaticojejunostomy being a key and challenging aspect. Pancreatic fistula is a serious and potentially dangerous postoperative complication. To reduce the incidence of postoperative pancreatic fistula, pancreaticojejunostomy techniques have been continuously improved. Currently, the placement of a pancreatic drainage tube in the pancreaticojejunostomy site (pancreatic duct to mucosa) is widely used clinically. This is a safe and effective method for reconstructing the digestive tract at the pancreatic stump. The drainage tube removes pancreatic juice from the anastomosis area, reducing the incidence of clinical pancreatic fistula and serious complications. Depending on whether the distal end of the drainage tube is located in the intestinal lumen or the abdominal wall, it is classified as an internal drainage tube or an external drainage tube.

[0003] Internal drainage offers advantages such as shorter hospital stays, simpler procedures, lower costs, reduced postoperative pain, and avoidance of complications associated with external drainage, gradually becoming the mainstream drainage method. However, clinically, there is still a lack of practical and effective internal pancreatic duct drainage tubes specifically designed for anastomosis between the main pancreatic duct and the digestive tract. Most surgeons still use silicone tubes or polyvinyl chloride (PVC) drainage tubes as substitutes. However, the use of these drainage tubes has significant limitations. For example, the main pancreatic duct often has morphological changes such as being too thin, narrow, or twisted, resulting in a mismatch in tube size and inability to fully adhere to the pancreatic duct wall, leading to poor drainage. Furthermore, the smooth surface of silicone or PVC drainage tubes lacks anti-slip properties; although sutures can be used for fixation during surgery, the rate of dislodgement remains high. In addition, these materials are non-degradable; short placement may lead to displacement, while long placement results in a low probability and long dislodgement time. Prolonged retention of the drainage tube in the pancreatic duct may induce serious complications such as postoperative pancreatic duct stones and pancreatitis, severely impacting patient prognosis and long-term quality of life, and increasing the risk of secondary surgery.

[0004] Therefore, researching a biodegradable pancreatic drainage tube that conforms to the physiological morphology of the pancreatic duct, gradually changes diameter at each end, and is resistant to dislodgement has become an urgent technical problem to be solved. Summary of the Invention

[0005] To address the problems in the existing technology, this invention provides an internal drainage tube with progressively variable diameter at each end, which solves the defects of existing internal drainage. By utilizing the surface thread structure of the progressively variable diameter drainage tube, combined with the swelling properties of biodegradable materials, the friction between the drainage tube and the pancreatic duct wall is increased, reducing the probability of the drainage tube shifting due to intestinal peristalsis or pancreatic fluid flushing.

[0006] To achieve the above technical objectives, the technical solution of the present invention is as follows: An internal drainage tube with progressively changing diameter at each end includes: a drainage tube with progressively changing diameter at each end, wherein the drainage tube is a hollow conical tubular structure and the surface of the drainage tube has a regularly arranged thread structure.

[0007] The inner diameter of the small-diameter end of the drainage tube is 0.8-3mm, the inner diameter of the large-diameter end is 1-5mm, and the length is 3-20cm.

[0008] The thread pitch of the threaded structure on the surface of the drainage tube is 0.2-2mm.

[0009] The drainage tubes are all made of biodegradable materials, and each drainage tube includes at least two electrospun layers composed of biodegradable materials and at least one monofilament support layer from the inside out, forming a composite membrane, which is then prepared through tube winding, shaping and demolding processes.

[0010] Furthermore, the inner layer of the drainage tube is composed of a biodegradable electrospun layer, and the biodegradable material of the electrospun layer is one or more of polyester polymers, polyether polymers, other polymers, and natural auxiliary spinning polymers. The polyester polymers are one or more of polylactic acid (PLA), polycaprolactone (PCL), polylactic-glycolic acid (PGLA), polylactic-polycaprolactone (PLCL), polydioxanone (PDO), polyglycolic acid-trimethylene carbonate (PGATMC), polylactic acid (PLA), PLA-b-PEG, and PLA-PEG-PLA; the polyether polymers are one or more of polyvinyl alcohol (PVA), polyethylene glycol (PEG), and polyethylene oxide (PEO); the other polymers are one or more of polyacrylonitrile (PAN), polyurethane (PU), and polyvinylidene fluoride (PVDF); and the natural auxiliary spinning polymers are one or more of silk fibroin, egg white protein, chitosan, and cellulose derivatives.

[0011] Furthermore, the middle layer of the drainage tube is composed of a biodegradable monofilament layer, and the biodegradable material of the monofilament layer is one or more of the following: polydioxanone (PDO), polyglycolic acid (PGA), polyglycolic acid-caprolactone (PGCL), polylactic acid (PLA), polybutylene adipate / terephthalate (PBAT), polycaprolactone (PCL), and polylactic acid-glycolic acid copolymer (PLGA).

[0012] Furthermore, the outer layer of the drainage tube is composed of a biodegradable electrospun layer, and the biodegradable material of the electrospun layer is one or more of polyester polymers, polyether polymers, other polymers, and natural auxiliary spinning polymers. The polyester polymers are one or more of polylactic acid (PLA), polycaprolactone (PCL), polylactic-glycolic acid (PGLA), polylactic-polycaprolactone (PLCL), polydioxanone (PDO), polyglycolic acid-trimethylene carbonate (PGATMC), polylactic acid (PLA), PLA-b-PEG, and PLA-PEG-PLA; the polyether polymers are one or more of polyvinyl alcohol (PVA), polyethylene glycol (PEG), and polyethylene oxide (PEO); the other polymers are one or more of polyacrylonitrile (PAN), polyurethane (PU), and polyvinylidene fluoride (PVDF); and the natural auxiliary spinning polymers are one or more of silk fibroin, egg white protein, chitosan, and cellulose derivatives.

[0013] Furthermore, the biodegradable material in the inner and outer layers of the drainage tube has a mass concentration of 10-50% W / V, and the monofilament layer of the drainage tube uses one or more of the following monofilament types: 2, 1, 0, 2-0, 3-0, 4-0, 5-0, 6-0, 7-0, 8-0, 9-0, and 10-0.

[0014] The tapered rod in the tube rolling process has a size range of 0.5-8mm and a length of 3-30cm. The release and anti-sticking layer material is polytetrafluoroethylene and its derivatives.

[0015] Furthermore, the solvent in the setting process is one or two of hexafluoroisopropanol, acetone, dichloromethane, ethanol, N,N-dimethylformamide (DMF), formic acid (FA), and tetrahydrofuran (THF), with a ratio ranging from 1-9:9-1; the setting temperature of the setting process is 25-65℃.

[0016] The method for preparing the internal drainage tapered tube includes the following steps: Step 1: Prepare the inner layer spinning solution using biodegradable materials and perform inner layer spinning to obtain the inner layer membrane; Step 2: After the inner layer spinning is completed, the monofilaments are wound onto the surface of the inner layer membrane at the same interval using a winding device; Step 3: After the winding is completed, the outer layer is spun on its surface, and after the spinning is completed, the film is demolded and hot-pressed at 25-65℃ for 5-60 minutes to obtain the composite film. Step 4: Cut the composite membrane and prepare a reducing tube using a tube rolling machine. Solvent is used to fix the shape during the tube rolling process. Finally, heat-dry and demold to obtain the drainage tube.

[0017] As can be seen from the above description, the present invention has the following advantages: 1. This invention addresses the shortcomings of existing internal drainage methods. It utilizes a drainage tube with a progressively variable diameter and a surface thread structure, combined with the swelling properties of a biodegradable material, to increase the friction between the drainage tube and the pancreatic duct wall, reducing the probability of displacement due to intestinal peristalsis or pancreatic fluid flushing. Specifically, the thread pitch and height are determined by the winding spacing and the diameter of different types of monofilaments. The thread structure increases the contact surface area, forming a mechanical interlock with the pancreatic duct wall tissue at the microscopic level. Compared to the smooth surface of PVC or silicone tubes, it is more effective in resisting the displacement forces generated by regular intestinal peristalsis and continuous pancreatic fluid flushing. Simultaneously, the variable diameter tube uses biodegradable biomaterials; after implantation, the material undergoes controlled swelling upon contact with pancreatic fluid, increasing the fit between the thread structure and the tube wall over time.

[0018] 2. The internal drainage tube with progressively variable diameter prepared in this invention achieves controllability of length and outer diameter through adjustment of the spun yarn membrane. Furthermore, its bendable diameter-variable characteristic allows the drainage tube to conform to the gradually tapering shape of the pancreatic duct, avoiding mucosal damage caused by localized stress concentration. By controlling the size of the conical rod, different materials, and the type of monofilament, the drainage tube of this invention achieves adjustable diameter and flexibility, conforming to the natural anatomical shape of the pancreatic duct. In comparison, traditional straight or single-curvature stents, after implantation into a curved pancreatic duct, can cause continuous point pressure on the local mucosa due to the mismatch between their rigidity and the lumen, leading to a relatively high probability of complications such as mucosal ischemia and erosion with long-term implantation. Simultaneously, the bendable diameter-variable characteristic of this invention ensures a large-area, uniform surface contact between the drainage tube and the pancreatic duct wall, efficiently dispersing concentrated point stress into gentle surface stress, reducing the probability of iatrogenic mucosal damage caused by mechanical compression.

[0019] 3. The drainage tube prepared by this invention is made from different degradable materials. By selecting different biodegradable materials, the degradation rate of the drainage tube can be controlled, achieving layered degradation. When the polymer material with a fast degradation rate becomes brittle and breaks into fragments, the polymer filaments or mesh with a slower degradation rate can act as a connector, preventing large fragments from clogging the tube. This invention allows the degradation cycle to be adjusted according to needs, matching the degradation curve with the treatment cycle to ensure that significant degradation only begins after the treatment mission is completed. Traditional non-degradable stents require automatic dislodgement, which generally takes a long time, or if they cannot dislodge automatically, a second surgery is required for removal.

[0020] 4. This invention's internal drainage tube with progressively varying diameter is fabricated using an electrospinning process. The spun membrane possesses an ECM-like structure, which is more conducive to cell growth. The microporous structure reduces the probability of drainage tube blockage due to protein deposition. The three-dimensional nanofiber network constructed by the electrospinning process is highly similar to the human body's natural extracellular matrix (ECM) in structure, scale, and topology. This biomimetic structure provides a familiar growth environment for pancreatic duct wall epithelial cells, greatly reducing foreign body reactions and actively guiding cells to adhere, spread, and proliferate normally. Unlike traditional materials (such as silicone and polyurethane) that may induce fiber encapsulation or inflammatory reactions, this type of ECM structure promotes physiological repair rather than pathological scar formation, while minimizing the risk of tube end blockage due to excessive tissue proliferation. Attached Figure Description

[0021] Figure 1 These are images of the internal drainage tapered tubes prepared in Examples 1-5. Detailed Implementation

[0022] Combination Figure 1 This article describes a specific embodiment of the present invention in detail, but does not limit the scope of the claims of the present invention in any way.

[0023] Example 1 A method for preparing an internal drainage tapered tube includes the following steps: 15g of PLCL was dissolved in 100mL of a mixed solvent of hexafluoroisopropanol and dichloromethane in a ratio of 4:6. The spinning parameters were adjusted to a voltage of 25kV, a feed rate of 25uL / min, a height of 28cm, and a humidity of 45%RH. Spinning was carried out for 2 hours to obtain a PLCL membrane. Then, 4-0PDO monofilaments were wound onto the surface of the PLCL membrane using a winding machine at a set spacing of 0.5mm to obtain a PDO monofilament layer. Spinning was then carried out on the surface of the PDO monofilament layer for another 2 hours to obtain a PLCL / PDO / PLCL composite membrane.

[0024] The composite membrane was cut into rectangles of 8*10cm. Using a tube rolling device, the composite membrane was prepared into a reducing tube with an outer diameter of 1mm at the small diameter end and 3.5mm at the large diameter end. The tube was then fixed using a 6:4 mixture of acetone and ethanol. After that, it was baked at 45℃ for 25 minutes. After demolding, it was cut into reducing tubes with an outer diameter of 1mm at the small diameter end, 3mm at the large diameter end, and a length of 5cm.

[0025] Example 2 A method for preparing an internal drainage tapered tube includes the following steps: 15g of PLCL was dissolved in 100mL of a mixed solvent of hexafluoroisopropanol and dichloromethane in a ratio of 4:6. The spinning parameters were adjusted to a voltage of 25kV, a feed rate of 25uL / min, a height of 28cm, and a humidity of 45%RH. Spinning was carried out for 2 hours to obtain a PLCL membrane. Then, 4-0PGCL monofilaments were wound onto the surface of the PLCL membrane using a winding machine at a set spacing of 0.5 mm to obtain a PGCL monofilament layer. Spinning was then carried out on the surface of the PGCL monofilament layer for another 2 hours to obtain a PLCL / PGCL / PLCL composite membrane.

[0026] The composite membrane was cut into rectangles of 8*10cm. Using a tube-winding device, the composite membrane was prepared into a reducing tube with an outer diameter of 1mm at the small diameter end and 3.5mm at the large diameter end. The tube was then fixed using a mixture of acetone and ethanol in a ratio of 6:4. After that, it was baked at 45℃ for 25 minutes. After demolding, it was cut into reducing tubes with an outer diameter of 1mm at the small diameter end, 3mm at the large diameter end, and a length of 5cm.

[0027] Example 3 A method for preparing an internal drainage tapered tube includes the following steps: 15g of PLCL was dissolved in 100mL of a mixed solvent of hexafluoroisopropanol and dichloromethane in a ratio of 4:6. The spinning parameters were adjusted to a voltage of 25kV, a feed rate of 25uL / min, a height of 28cm, and a humidity of 45%RH. Spinning was carried out for 2 hours to obtain a PLCL membrane. Then, 6-0PGCL monofilaments were wound onto the surface of the PLCL membrane using a winding machine at a set spacing of 0.8 mm to obtain a PGCL monofilament layer. Spinning was then carried out on the surface of the PGCL monofilament layer for another 2 hours to obtain a PLCL / PGCL / PLCL composite membrane.

[0028] The composite membrane was cut into 8*10cm rectangles and then rolled into a reducing tube with a small diameter of 1mm and a large diameter of 3.5mm using a tube rolling device. The tube was then fixed using a 6:4 mixture of acetone and ethanol, and then baked at 45℃ for 25 minutes. After demolding, the tube was cut into a reducing tube with a small diameter of 1mm, a large diameter of 3mm, and a length of 5cm.

[0029] Example 4 A method for preparing an internal drainage tapered tube includes the following steps: 7.5g of PLCL was dissolved in a mixed solvent of hexafluoroisopropanol and dichloromethane in a ratio of 4:6. The spinning parameters were adjusted to a voltage of 25kV, a feed rate of 25uL / min, a height of 28cm, and a humidity of 45%RH. Spinning was carried out for 2 hours to obtain a PLCL film. Then, 6-0PGCL monofilaments were wound onto the surface of the PLCL film using a winding machine at a set spacing of 0.8mm to obtain a PGCL monofilament layer. 7.5g of PGLA was dissolved in a mixed solvent of hexafluoroisopropanol and dichloromethane in a ratio of 3:1. The spinning parameters were adjusted to a voltage of 28kV, a feed rate of 30uL / min, a height of 28cm, and a humidity of 55%RH. Spinning was carried out on the PGCL surface for 2 hours to obtain a PLCL / PGCL / PGLA composite film.

[0030] The composite membrane was cut into rectangles of 8*10cm. Using a tube-winding device, the composite membrane was prepared into a reducing tube with an outer diameter of 1mm at the small end and 3.5mm at the large end. The tube was then shaped using a 1:1 mixture of hexafluoroisopropanol and ethanol. After that, it was baked at 45℃ for 25 minutes. After demolding, it was cut into reducing tubes with an outer diameter of 1mm at the small end, 3mm at the large end, and a length of 5cm.

[0031] Example 5 A method for preparing an internal drainage tapered tube includes the following steps: 7.5g of PCL was dissolved in a mixed solvent of hexafluoroisopropanol and dichloromethane in a ratio of 4:6. The spinning parameters were adjusted to a voltage of 30kV, a feed rate of 30uL / min, a height of 28cm, and a humidity of 45%RH. Spinning was carried out for 2 hours to obtain a PCL membrane. Then, 6-0 PGCL monofilaments were wound onto the surface of the PCL membrane using a winding machine at a set spacing of 0.8mm to obtain a PGCL monofilament layer. Spinning was carried out on the PCL surface for 2 hours to obtain a PCL / PGCL / PCL composite membrane.

[0032] The composite membrane was cut into rectangles of 8*10cm. Using a tube rolling device, the composite membrane was prepared into a reducing tube with an outer diameter of 1mm at the small diameter end and 3.5mm at the large diameter end. The tube was then fixed using a 1:1 mixture of acetone and ethanol. After that, it was baked at 45℃ for 15 minutes. After demolding, it was cut into a reducing tube with an outer diameter of 1mm at the small diameter end, 3mm at the large diameter end, and a length of 5cm.

[0033] Performance testing 1. Appearance of the reducing pipe The internal drainage tapered tubes prepared in Examples 1-5 are as follows: Figure 1As shown, in Examples 1, 2, and 3, both the inner and outer spinning layers are PLCL, with smooth and relatively soft outer surfaces. Example 1 uses a 4-0 PDO monofilament layer, which has strong resilience. Examples 2 and 3 use 4-0 PGCL and 6-0 PGCL monofilament layers, respectively, both exhibiting good flexibility. Example 4 uses a PGLA spinning layer for the outer layer, resulting in a stiffer drainage tube compared to other examples. Example 5 uses PCL for both inner and outer layers, with PGCL monofilaments, making it relatively soft. The above examples use different types of monofilaments, adjusting the spacing to form threaded layers of varying depths and intervals; the length is 5cm, the outer diameter at the small diameter end is 1mm, and the outer diameter at the large diameter end is 3mm.

[0034] 2. Bending performance Using the internal drainage tapered tubes prepared in Examples 3-5 as test samples, the bending performance test was conducted according to the standard YY / T 1282-2022 "Disposable Indwelling Intravenous Catheters". The drainage tube was inserted into the bending resistance test channel, and the bending resistance of the drainage tube was evaluated by observing whether the drainage tube kinked. The test results showed that the internal drainage tapered tube of Example 3 passed through normally without kinking; the internal drainage tapered tube of Example 4 passed through normally without kinking; and the internal drainage tapered tube of Example 5 passed through normally without kinking.

[0035] 3. Traffic Using the internal drainage variable-diameter tubes prepared in Examples 3-5 as test samples, the flow rate test was conducted according to the flow rate test method in GB / T 15812.1-2005 Non-vascular Catheters Part 1: General Performance Test Methods. The equipment included a constant-level water tank equipped with a water supply pipe and a connector with a cone (or cone seat). When the drainage tube was not connected, the flow rate should be no less than 500 mL / min. Unless otherwise specified in the product standard, the constant-level water tank should preferably have a static pressure head with a height of (1000 ± 10) mm. A graduated cylinder or a collection container with a weight accuracy of ± 1% was also used. The procedure was as follows: Water was added to the constant-level water tank at (23 ± 2) °C and connected to the test drainage tube using the appropriate connector; water was injected into the drainage tube, and air was expelled; water was allowed to flow through the drainage tube, and the outflow was collected in a suitable container over a period of not less than 30 seconds. The outflow was measured using a graduated cylinder or by weighing, with the density of water being 1000 kg / m³. 3 The volume was measured using a conversion method. Each drainage tube was measured three times. The result is expressed as the average of the three measurements, in milliliters per minute. The calculated average flow rate was rounded to the nearest integer.

[0036]

[0037] The above tests show that the internal drainage variable diameter tubes prepared in Examples 3-5 can all flow normally without significant flow loss.

[0038] 4. Test for resistance to parallel plate extrusion Using the internal drainage variable-diameter catheters prepared in Examples 3-5 as test samples, the tests were conducted in accordance with YY / T 0663.2-2016 Cardiovascular Implants - Endovascular Devices - Part 2: Vascular Stents. The load / deformation characteristics of the catheter were measured when a radially uniformly distributed load was applied to its circumference. Tests were performed on the large-diameter end, small-diameter end, and transition zone of the variable-diameter catheter. The stent was fixed to the test fixture; the stent was compressed at a constant compression rate (5 mm / min); the load and corresponding diameter were recorded during stent compression until the force significantly decreased or the diameter decreased by at least 50%.

[0039]

[0040] The above data shows that Example 4 has the strongest resistance to compression, with no change before and after the channel; Example 3 has weaker resistance to compression at the middle diameter end; and Example 5 has weaker resistance to compression at the large diameter end.

[0041] 5. Fracture strength Using the internal drainage variable diameter tubes prepared in Examples 3-5 as test samples, and referring to the standard "YY / T 0489-2023 Disposable Sterile Drainage Catheters and Auxiliary Instruments", a tensile force with a gauge length of 20 mm / min per unit strain rate was applied to each sample until the tube broke or the connection separated, and the maximum breaking force was obtained.

[0042]

[0043] The above data shows that the breaking strength of Example 4 is greater than that of Example 5 and Example 3, indicating that PGLA spinning film can enhance the strength and hardness of the drainage tube, while PLCL and PCL are relatively soft.

[0044] It is understood that the above detailed description of the present invention is for illustrative purposes only and is not intended to limit the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention to achieve the same technical effects; as long as the usage requirements are met, they are all within the protection scope of the present invention.

Claims

1. An end-ducting telescoping tube for internal drainage, characterized in that: The application relates to a drainage tube with a variable diameter from one end to the other. The small-diameter end of the drainage tube has an inner diameter of 0.8-3 mm, the large-diameter end has an inner diameter of 1-5 mm, and the length is 3-20 cm.

2. The internally-draining telescoping tube of claim 1, wherein: The thread spacing of the thread structure on the surface of the drainage tube is 0.2-2 mm.

3. The internally-draining telescoping tube of claim 1, wherein: The drainage tube is made of biodegradable materials, and the drainage tube comprises at least two layers of electrostatic spinning layers and at least one layer of monofilament support layers from the inside to the outside, is prepared into a composite film, and is prepared through a pipe winding process, a shaping process and a demolding process.

4. The internally-draining telescoping tube of claim 1, wherein: The inner layer of the drainage tube is composed of a biodegradable electrostatic spinning layer, and the biodegradable material of the electrostatic spinning layer is one or more of polyester polymers, polyether polymers, other polymers and natural spinning polymer. The polyester polymers are one or more of polylactic acid (PLA), polycaprolactone (PCL), polyglycolic acid (PGLA), polylactic acid-polycaprolactone (PLCL), poly-p-dioxanone (PDO), polyglycolic acid-trimethylene carbonate (PGATMC), polylactic acid (PLA), PLA-b-PEG and PLA-PEG-PLA; the polyether polymers are one or more of polyvinyl alcohol (PVA), polyethylene glycol (PEG) and polyethylene oxide (PEO); the other polymers are one or more of polyacrylonitrile (PAN), polyurethane (PU) and polyvinylidene fluoride (PVDF); and the natural spinning polymer is one or more of silk fibroin, egg white protein, chitosan and cellulose derivative.

5. The internally-draining telescopic tapering tube of claim 4, wherein: The middle layer of the drainage tube is composed of a biodegradable monofilament layer, and the biodegradable material of the monofilament layer is one or more of poly-p-dioxanone (PDO), polyglycolic acid (PGA), polyglycolide-caprolactone (PGCL), polylactic acid (PLA), polybutylene adipate / terephthalate (PBAT), polycaprolactone (PCL) and poly-lactic-glycolic acid copolymer (PLGA). ​ The outer layer of the drainage tube is composed of a biodegradable electrospun layer, and the biodegradable material of the electrospun layer is one or more of polyester polymers, polyether polymers, other polymers, and natural auxiliary spinning polymers. The polyester polymers are one or more of polylactic acid (PLA), polycaprolactone (PCL), polyglycolic acid (PGLA), polylactic acid-polycaprolactone (PLCL), poly-p-dioxanone (PDO), polyglycolic acid-trimethylene carbonate (PGATMC), polylactic acid (PLA), PLA-b-PEG, and PLA-PEG-PLA; the polyether polymers are one or more of polyvinyl alcohol (PVA), polyethylene glycol (PEG), and polyethylene oxide (PEO); the other polymers are one or more of polyacrylonitrile (PAN), polyurethane (PU), and polyvinylidene fluoride (PVDF); and the natural auxiliary spinning polymers are one or more of silk fibroin, egg white protein, chitosan, and cellulose derivatives.

6. The internally-draining telescopic variable diameter tube of claim 4, wherein: The mass concentration of the biodegradable material in the inner layer and the outer layer of the drainage tube is 10-50% W / V, and the monofilament type used in the monofilament layer of the drainage tube is one or more of 2, 1, 0, 2-0, 3-0, 4-0, 5-0, 6-0, 7-0, 8-0, 9-0, and 10-0.

7. The internally-draining telescopic variable diameter tube of claim 4, wherein: The size of the mandrel in the winding process ranges from 0.5 to 8 mm, and the length ranges from 3 to 30 cm. The anti-sticking layer material is polytetrafluoroethylene and its derivatives.

8. The internally-draining telescopic tapering tube of claim 4, wherein: The solvent used in the shaping process is one or two of hexafluoroisopropanol, acetone, dichloromethane, ethanol, N-N dimethylformamide (DMF), formic acid (FA), and tetrahydrofuran (THF), with a proportion ranging from 1-9 : 9-1. The shaping temperature of the shaping process is 25-65℃.

9. The internally-draining telescopic variable diameter tube of claim 4, wherein: The preparation method of the inner drainage variable-diameter tube includes the following steps: Step 1: Prepare the inner layer spinning solution with biodegradable material and perform inner layer spinning to obtain the inner layer film. Step 2: After the inner layer spinning is completed, the monofilaments are wound onto the surface of the inner layer film at the same interval by winding equipment. Step 3: After winding is completed, outer layer spinning is performed on the surface, and after spinning is completed, the mandrel is removed. Heat pressing is performed at 25-65℃ for 5-60min to obtain a composite film. Step 4: The composite film is cut and a variable-diameter tube is prepared by a tube winding machine. Solvent shaping is performed during the tube winding process, and finally the mandrel is removed by heat baking to obtain the drainage tube.

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