A flexible outer sleeve 70, 170 (partially shown in FIGS. 2 and 7) may be disposed on the outside of the articulation mechanism 10 to provide a smooth exterior surface. The outer sleeve 70, 170 can be made from soft, thin polyurethane, LLDPE, silicon, pellethane, polyurethane, or other approved biocompatible materials such as polyethylene, polypropylene or polyvinyl alcohol. Additionally, the outer sleeve 70, 170 can be coated with a hydrophilic, lubricious coating such as HYDROPASS™ hydrophilic coating available from Boston Scientific Corporation, of Natick, Mass., and described in U.S. Pat. Nos. 5,702,754 and 6,048,620, which are herein incorporated by reference. Additionally, the outer sleeve 70, 170 can be coated with a drug agent to treat internal body tissues.
