Variable diameter tubular structure for a biomedical use
A plastics material variable diameter tubular structure for a biomedical use has a diameter which increases as the structure is subjected to an inner force, and returns to a starting diameter in a rest condition of the structure, the tubular structure being advantageously used for making a body of a vascular introducer device.
1 . A biomedical variable diameter tubular structure, characterized in that said structure comprises an extruded tube, which is longitudinally cut and thermoformed to define a longitudinal region having overlapping walls sliding with respect to one another in a radial direction, said walls moving away as an article having a size larger than a rest diameter of said tube passes through said tube.
2 . A tubular structure, according to claim 1 , characterized in that said tube is coupled to a resilient sheath extending through an overall length of said tube.
3 . A tubular structure, according to claim 1 , characterized in that said tube, in an extruded and thermoformed condition thereof, has a variable thickness and two perfectly overlapped open flaps or edges thereof thereby providing a precise thickness of said tube, where said tube is in a minimum diameter configuration thereof.
4 . A tubular structure, according to claim 1 , characterized in that said tube has an eccentric thickness.
5 . A tubular structure, according to claim 1 , characterized in that said tube is extruded to an even thickness, the movable flap or tube portions being overlapped, and being thermoformed to a non linear profile including rough portions either inward and/or outward directed.
6 . A tubular structure, according to claim 1 , characterized in that said tubular structure is made of a polyamide material.
7 . A tubular structure, according to claim 2 , characterized in that said sheath comprises a resilient membrane extending either through a part of a tube length or through all the tube length, and all the tube profile, said membrane being made of a polyurethane material and coated on the tube, in a rest diameter condition of said tube, by a dipping coating method.
8 . A vascular introducer device, characterized in that said device comprises an extruded tubular structure according to claim 1 , said tubular structure being longitudinally cut and thermoformed to define a longitudinal region having overlapping walls which may slide in a radial direction with respect to one another and to move away as an article having a size larger than a rest diameter of said tubular structure passes through said tubular structure, said tubular structure being coupled to a resilient outer sheath extending through a part or all a length of said tubular structure, a proximal part of said tubular structure being sealed to a valve adapted to hold said tubular structure in a maximum diameter condition thereof, a tip of said tubular structure tapering toward a dilating device therefor.
9 . An introducer device, according to claim 8 , characterized in that said tubular structure has an end portion thereof coupled to a retaining valve with a side arm and an atraumatic blunted tip, the valve being a haemostatic valve comprising a stiff fitting including a silicone diaphragm insulating the outside and inside of a body vessel while allowing a medical device to pass therethrough, said silicone diaphragm being precut in the form of a central star by cuts snugly adhering to said medical device.
10 . An introducer device, according to claim 9 , characterized in that said device comprises, near said valve, a diameter transition conical region.
11 . An introducer device, according to claim 8 , characterized in that said tubular structure is clamped by engaging therewithin a second tubular structure.
12 . An introducer device, according to claim 9 , characterized in that said introducer device has a truncated tip, Said medical device including a dilatator element having a removable tip portion adapted to protect body tissues against said introducer device truncated tip.