Hydrophilic graft copolymers: a new concept in urological surgery.

Hydrophilic graft copolymers are derived from hydrophobic polymers which have been copolymerized and then grafted by radiation initiation so that they become hydrophilic. Tubes of such material expand in diameter by 60% when wet and become slippery. The first medical applications of these materials are described: they have been used as an access conduit for percutaneous renal surgery and endoscopic access to the ureter.