A surgical sleeve which includes an array of spaced apart protuberances on an interior wall surface. The spaced protuberance reduce the surface contact between the sleeve and the tip and define a network of generally uniform channels through which fluid may flow, irrespective of pressure applied to the...http://www.google.com/patents/US5984904?utm_source=gb-gplus-sharePatent US5984904 - Sleeve for a surgical instrument
