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CN-122005949-A - Manufacturing method and application of minimally invasive stent for chronic appendicitis

CN122005949ACN 122005949 ACN122005949 ACN 122005949ACN-122005949-A

Abstract

The invention discloses a manufacturing method and application of a minimally invasive stent for chronic appendicitis, and relates to the technical field of medical appliances. The preparation method and application of the minimally invasive stent for the chronic appendicitis are characterized in that the stent takes nickel-titanium shape memory alloy as a base material, and the preparation steps comprise S1, preparing the nickel-titanium alloy base material, namely selecting nickel-titanium shape memory alloy wires with the nickel content of 54-56at% and the titanium content of 44-46at%, removing internal stress through vacuum annealing treatment, wherein the annealing temperature is 500-550 ℃, preserving the heat for 1-2h, and cooling to room temperature for later use. The manufacturing method and the application of the minimally invasive stent for the chronic appendicitis adopt nickel-titanium shape memory alloy, realize accurate switching of the diameter of the stent between 3.5mm (supporting state) and 0.8mm (shrinking state) through temperature response, adapt to the aperture tail tube cavities with different narrow degrees, and the stent has flexibility, can adapt to the appendiceal bending structure, and solve the problems of fixed size and poor adaptability of the existing alternative stent.

Inventors

  • GUO XIANBIN
  • ZHENG JINHUI

Assignees

  • 福州大学附属省立医院

Dates

Publication Date
20260512
Application Date
20260226

Claims (7)

  1. 1. A method for manufacturing a minimally invasive stent for chronic appendicitis is characterized in that the stent uses nickel-titanium shape memory alloy as a base material, and the manufacturing steps comprise: S1, preparing a nickel-titanium alloy substrate, namely selecting a nickel-titanium shape memory alloy wire with the nickel content of 54-56at% and the titanium content of 44-46at%, removing internal stress through vacuum annealing treatment, keeping the annealing temperature at 500-550 ℃, keeping the temperature for 1-2h, and cooling to room temperature for later use; s2, pipe machining and forming, namely machining the nickel-titanium alloy wire treated in the step S1 into a hollow pipe through a precise drawing process, and then cutting and trimming the hollow pipe into a pipe blank with the length of 60mm through laser, so that the initial outer diameter of the pipe blank is 3.5mm, and the inner diameter of the pipe blank is 3.3mm; S3, full-film coating treatment, namely, carrying out full-outer-surface film coating treatment on the tubular product blank by adopting a medical-grade biocompatible film coating material, wherein the film coating thickness is 0.05-0.1mm, and tightly attaching the film coating to the tubular product blank through a hot-pressing composite process, so that no peeling risk is ensured, and the adhesion between a bracket and appendiceal tissue is prevented; S4, shape memory shaping, namely placing the tube blank subjected to film coating in a shaping die, heating to 500-550 ℃ and preserving heat for 30-60min, and setting an initial shape; cooling to 40-45 ℃, applying radial pressure to shrink the pipe to the outside diameter of 1mm and the inside diameter of 0.8mm, preserving heat for 20-30min, and cooling to room temperature to complete the setting of the two-way shape memory effect; S5, assembling a support lining, namely selecting a medical-grade hard plastic or stainless steel lining rod, wherein the outer diameter of the lining rod is matched with the inner diameter of the pipe in the initial form in the step S4, and the lining rod is inserted into the formed pipe and used for maintaining the initial form of the support in the transportation and storage processes so as to prevent deformation; s6, sterilizing and packaging, namely sterilizing the bracket provided with the lining rod by using ethylene oxide for 6-8 hours, and sealing by adopting sterile packaging after sterilization to obtain a finished product.
  2. 2. The method for manufacturing a minimally invasive stent for chronic appendicitis according to claim 1, wherein the medical grade biocompatible coating material in the step S3 is polytetrafluoroethylene, the thickness of the medical grade biocompatible coating material is 0.08mm, the hot-pressing compounding temperature is 120-150 ℃, the pressure is 0.3-0.5MPa, and the compounding time is 10-15min.
  3. 3. The method for manufacturing a minimally invasive stent for chronic appendicitis according to claim 1, wherein the shaping mold in the step S4 is made of high-temperature-resistant stainless steel, the inner wall of the mold is smooth, the tolerance range is +/-0.01 mm, and the dimensional accuracy of the stent is ensured.
  4. 4. The method of claim 1, wherein the length of the support lining rod in the step S5 is 65mm, the two ends of the support lining rod are rounded, and the radius of the rounded corner is 0.5-1mm.
  5. 5. The use of a minimally invasive stent for chronic appendicitis according to any of claims 1-4, in the context of endoscopic retrograde appendicitis treatment, comprising the steps of: Step one, preoperative evaluation, namely checking and determining whether the appendiceal cavity of the patient has stenosis or obstruction by ERAT, and determining the indication of the stent to be placed; Step two, preparing the bracket, namely dismantling sterile package of the finished bracket, taking out the bracket, and removing an inner supporting lining rod for standby; Step three, stent placement, namely placing the stent into the appendiceal cavity through the insertion tube of the appendiceal opening by the guidance of an endoscope in ERAT operation, wherein the stent is in an initial form in the placement process, so that the stent is tightly attached to the inner wall of the cavity of the stop tail tube, and radial supporting force of not less than 0.5N is provided to resist the collapse of the appendiceal tube; Step four, flushing in operation, namely injecting normal saline into the appendiceal cavity through an endoscope channel for full flushing after the stent is placed, removing pus and fecaluria residues, and realizing drainage by utilizing the hollow structure of the stent; step five, retention and maintenance, namely, the stent is retained in the body for 1 week, the stent is prevented from adhering to the appendiceal tissue by virtue of a full-covered structure during the retention period, and the drainage effect is continuously ensured through a hollow channel, so that blockage is avoided; Step six, stent taking out/discharging, namely after the retention is expired, normal saline at 42-43 ℃ is injected into the appendiceal cavity through an endoscope channel, flushing is continuously performed for 3-5min, the stent is triggered to shrink to a contracted form, and then the stent is taken out through an endoscope instrument or is allowed to be discharged out of the body along with intestinal peristalsis.
  6. 6. The method according to claim 5, wherein when the stent is placed in the third step, if the cavity of the stop tail tube is curved, the flexibility of the nickel-titanium alloy is utilized to enable the stent to adapt to the curved structure of the appendix without adjusting the angle of the insertion tube additionally.
  7. 7. The method according to claim 5, wherein the flushing flow of the normal saline in the sixth step is 5-10ml/min, so as to ensure that the stent is sufficiently contracted and then taken out.

Description

Manufacturing method and application of minimally invasive stent for chronic appendicitis Technical Field The invention relates to the technical field of medical appliances, in particular to a manufacturing method and application of a minimally invasive stent for chronic appendicitis. Background Endoscopic Retrograde Appendicitis (ERAT) is a minimally invasive technique for treating chronic appendicitis, and has the core requirement that the appendicitis is placed into an appendiceal cavity through a stent to realize lumen support, pus and fexid drainage so as to relieve inflammation and avoid surgical excision, however, no special stent designed aiming at the anatomical structure and physiological characteristics of the appendix exists in clinic at present, and alternative products such as a bile duct stent, a pancreatic stent and the like of Endoscopic Retrograde Cholangiography (ERCP) are commonly used; the existing alternative stent has the defects that firstly, the suitability is poor, the diameter, the length and the running direction of the cavity of the diaphragm tail tube are obviously different from those of the biliary pancreatic duct, the appendix is in a diagonal trend, the individual variation of the narrow degree of the tube cavity is large, the size of the biliary pancreatic stent is customized for the biliary pancreatic duct, the problems of unstable fixation caused by too thick damage to the appendix wall, too thin gap leakage or inconsistent length of the stent easily occur, secondly, the drainage effectiveness is insufficient, pus and fecal residues need to be drained in the appendicitis period, the drainage channel of the biliary pancreatic stent is designed aiming at bile and pancreatic juice characteristics, the aperture and pore distribution of the biliary pancreatic stent are not matched with the viscosity of the appendiceal cavity secretion and the size of impurity particles, and the stent is easy to be blocked; The nickel-titanium shape memory alloy has excellent shape memory effect, superelasticity and biocompatibility, and is widely applied to the field of medical equipment, and based on the nickel-titanium shape memory alloy, the invention designs a minimally invasive chronic appendicitis stent made of nickel-titanium materials, and the temperature response type telescopic function is realized through an accurate manufacturing process, so that the technical defects of the existing alternative stent are overcome. Disclosure of Invention The invention aims to at least solve one of the technical problems in the prior art, and provides a manufacturing method and application of a minimally invasive stent for chronic appendicitis, which can solve the problems. In order to achieve the aim, the invention provides the following technical scheme that the manufacturing method of the minimally invasive stent for the chronic appendicitis comprises the following steps of: S1, preparing a nickel-titanium alloy substrate, namely selecting a nickel-titanium shape memory alloy wire with the nickel content of 54-56at% and the titanium content of 44-46at%, removing internal stress through vacuum annealing treatment, keeping the annealing temperature at 500-550 ℃, keeping the temperature for 1-2h, and cooling to room temperature for later use; s2, pipe machining and forming, namely machining the nickel-titanium alloy wire treated in the step S1 into a hollow pipe through a precise drawing process, and then cutting and trimming the hollow pipe into a pipe blank with the length of 60mm through laser, so that the initial outer diameter of the pipe blank is 3.5mm, and the inner diameter of the pipe blank is 3.3mm; S3, full-film coating treatment, namely, carrying out full-outer-surface film coating treatment on the tubular product blank by adopting a medical-grade biocompatible film coating material, wherein the film coating thickness is 0.05-0.1mm, and tightly attaching the film coating to the tubular product blank through a hot-pressing composite process, so that no peeling risk is ensured, and the adhesion between a bracket and appendiceal tissue is prevented; S4, shape memory shaping, namely placing the tube blank subjected to film coating in a shaping die, heating to 500-550 ℃ and preserving heat for 30-60min, and setting an initial shape; cooling to 40-45 ℃, applying radial pressure to shrink the pipe to the outside diameter of 1mm and the inside diameter of 0.8mm, preserving heat for 20-30min, and cooling to room temperature to complete the setting of the two-way shape memory effect; S5, assembling a support lining, namely selecting a medical-grade hard plastic or stainless steel lining rod, wherein the outer diameter of the lining rod is matched with the inner diameter of the pipe in the initial form in the step S4, and the lining rod is inserted into the formed pipe and used for maintaining the initial form of the support in the transportation and storage processes so as to prevent deformation