Flexible tube having a tapered diameter portion for use with endoscopic irrigation instruments

摘要

An endoscopic irrigation instrument includes a fluid chamber, a cannula coupled to a distal end of the fluid chamber, a tapered irrigation tube which couples at its proximal end to a fluid source and which couples at its distal end to an irrigation port of the fluid chamber, and a pinch valve which controls the flow of fluid from the irrigation source to the fluid chamber and hence through the cannula to the surgical site. The tapered irrigation tube is arranged so that it has a first relatively larger constant inner diameter and relatively larger wall thickness on its proximal end until it tapers down in both inner diameter and wall thickness at a location slightly proximal the pinch valve. By the time the tapered irrigation tube passes the pinch valve in the endoscopic instrument, the tapered irrigation tube is at a second relatively smaller constant inner diameter and a relatively smaller wall thickness. The tapered irrigation tube thus enables greater fluid flow, pinch valve control at the thin distal end, and tube reliability at both high and low fluid pressures.