Laparoscopic ultrasonic surgical instrument and methods for manufacturing the instruments

摘要

The ultrasonic instrument includes a shaft having an integral sheath of PTFE encompassing the shaft and attached solely to the shaft. At the proximal end of the shaft, wrench flats are exposed through openings in the sheath and grooves cooperate with complementary ribs on the sheath, to prevent relative longitudinal and rotational displacement of the sheath and shaft. The sheath is in contact with the shaft at the nodes along the shaft. The diameter of the sheath is about 5 mm whereby the instrument may be used with a 5 mm trocar port. To manufacture the instrument, the sheath is initially formed to a diameter equal to or less than the diameter of the shaft and then mechanically expanded. Subsequently, the sheath is heat-shrunk about the shaft and rolled continuously along the shaft, except at regions corresponding to the nodes along the shaft, to expand the sheath to a larger diameter to space the sheath from the shaft except at the nodes of the shaft.