Artifical Graft Tubing

Abstract

A method of making artificial graft tubing includes providing a helical mandrel having a centre line following a substantially helical path, and providing a generally tubular wall having a longitudinally extending cavity. The helical mandrel is positioned inside the tubular wall so that the longitudinally extending cavity has a centre line following a substantially helical path. The tubular wall is caused to retain, at least partly, the shape with the longitudinally extending helical cavity. Another method includes providing a mandrel having a substantially helical groove, and providing a generally tubular wall having a longitudinally extending cavity. The tubular wall is positioned at least partly in the groove so that the longitudinally extending cavity has a centre line following a substantially helical path, and the tubular wall is caused to retain, at least partly, the shape with the longitudinally extending helical cavity.

1 . A method of making artificial graft tubing, comprising providing a helical mandrel having a centre line following a substantially helical path, providing a generally tubular wall having a longitudinally extending cavity, positioning the helical mandrel inside the tubular wall so that the longitudinally extending cavity has a centre line following a substantially helical path, and causing the tubular wall to retain, at least partly, the shape with the longitudinally extending helical cavity. 
   
   
       2 . A method as claimed in  claim 1 , wherein the tubular wall is initially substantially cylindrical. 
   
   
       3 . A method as claimed in  claim 1 , wherein the tubular wall is thermoset so as to retain, at least partially, the shape with the longitudinally extending cavity. 
   
   
       4 . A method as claimed in  claim 1 , wherein the tubular wall comprises a helically wound support. 
   
   
       5 . A method as claimed in  claim 1 , comprising applying an elongate member to the tubular wall so as to extend longitudinally thereof, when the tubular wall is supported by the mandrel. 
   
   
       6 . A method as claimed in  claim 5 , wherein the elongate member is applied to extend both circumferentially and longitudinally of the tubular wall. 
   
   
       7 . A method as claimed in  claim 6 , comprising securing the elongate member at one end and subjecting it to longitudinal tension whilst applying it to the tubular wall. 
   
   
       8 . A method as claimed in  claim 6 , wherein the elongate member is applied to extend helically along the tubular wall with a pitch substantially equal to the pitch of the helical centre line. 
   
   
       9 . A method as claimed in  claim 5 , wherein the elongate member is bonded to the tubular wall by a heating step. 
   
   
       10 . A method as claimed in  claim 9 , wherein the heating step is a single heating step serving both to bond the elongate member to the tubular wall and to thermoset the tubular wall to retain, at least partly, the shape with the longitudinally extending cavity. 
   
   
       11 . A method of making artificial graft tubing, the method comprising providing a generally tubular wall having a longitudinally extending cavity, shaping the tubular wall so that the longitudinally extending cavity has a centre line following a substantially helical path, causing the tubular wall to retain, at least partly, the shape with the longitudinally extending helical cavity, and thereafter applying to the tubular wall an elongate member so as to extend longitudinally thereof. 
   
   
       12 . A method as claimed in  claim 11 , wherein the elongate member is applied to extend both circumferentially and longitudinally of the tubular wall. 
   
   
       13 . A method as claimed in  claim 12 , wherein the elongate member is applied to extend helically along the tubular wall with a pitch substantially equal to the pitch of the helical centre line. 
   
   
       14 . A method as claimed in  claim 11 , wherein the step of causing the tubular wall to retain, at least partly, the helical shape comprises thermosetting the tubular wall. 
   
   
       15 . A method as claimed in  claim 11 , wherein the elongate member is bonded to the tubular wall by a heating step. 
   
   
       16 . A method as claimed in  claim 11 , wherein the tubular wall is shaped by being wound round a mandrel. 
   
   
       17 . A method as claimed in  claim 16 , wherein the mandrel has a substantially helical groove in which the tubular wall is at least partly received. 
   
   
       18 . A method as claimed in  claim 11 , wherein the tubular wall is shaped by positioning a substantially helical mandrel inside the tubular wall. 
   
   
       19 . A method as claimed in  claim 16 , wherein the elongate member is applied to the tubular wall when it is supported by the mandrel. 
   
   
       20 . A method as claimed in  claim 11 , wherein the elongate member is applied to the tubular wall externally thereof. 
   
   
       21 . A method of making artificial graft tubing, the method comprising providing a mandrel having a substantially helical groove, providing a generally tubular wall having a longitudinally extending cavity, positioning the tubular wall at least partly in the groove so that the longitudinally extending cavity has a centre line following a substantially helical path, and causing the tubular wall to retain, at least partly, the shape with the longitudinally extending helical cavity.