Method of producing vascular prostheses from synthetic fibrous materials

摘要

A vascular prosthesis comprising a knitted fibrous thermoplastic tube is helically crimped by drawing the tube over a helical former having spaced convolutions, constraining the tube into the spaces between the convolutions and heat setting and stress relieving the crimps. The knitted tube is drawn on to a tension or compression spring which is then extended or compressed to impart corrugations to the tube. The corrugations are then fixed by treating with dry heat, saturated steam or hot water. The tube may be drawn on to a spring with a solid core, a thread of synthetic material then being wound on the tube between the spring coils, the diameter of the core thus determining the depth of the corrugations formed. The tube may be treated to fix the corrugations before withdrawal from the spring or after transferring it to a solid rod and adjusting the corrugations to desired width and height.ALSO:A knitted fibrous thermoplastic tube is helically crimped by drawing it over a helical former having spaced convolutions, constraining the tube into the spaces between the convolutions and heat setting and stress relieving the tube. The knitted tube is drawn on to a tension or compression spring which is then extended or compressed to impart corrugations to the tube. The corrugations are fixed by treating with dry heat, saturated steam or hot water. The tube may be drawn on to a spring with a solid core, a thread of synthetic material then being wound on the tube between the spring coils, the diameter of the core thus determining the depth of the corrugations formed. The tube may be treated to fix the corrugations before withdrawal from the spring or after transfering it to a solid rod and adjusting the corrugations to desired width and height. The tube may be made of polyester fibrous material and may be knitted partly from fully or highly stretched threads and partly from slightly stretched or unstretched threads. Two threads may be knitted together, one thread being fully or highly stretched and the other being slightly stretched or unstretched.