LASER ENERGY CONCENTRATION IN LASER POWERED SURGICAL INSTRUMENT

摘要

A surgical instrument in the form of a needle has a distal port for receiving tissue. An optical fiber extends along the length of the needle and has its distal end positioned in a distal chamber of the needle. The chamber is in communication with the port. Pulses of laser energy are delivered to the distal end of the optical fiber. A small lens at the distal end of the optical fiber concentrates the pulses of laser energy to a focal point within the chamber. The chamber is normally filled with saline. The laser energy is sufficiently great and the focal zone is sufficiently small so that the focused laser energy produces plasma at the focal point from the saline in the chamber. The generation of plasma creates shockwaves that travel through the saline in the chamber and strike and fracture tissue which is held at the tissue receiving port. The inner wall of the chamber is a spherical segment. It also receives shockwaves. The wall reflects and because of its curvature concentrates those shockwaves at the tissue receiving port thereby providing an additional shockwave for fracturing tissue held at the port. Fractured tissue together with irrigating fluid is drawn out through an aspirating passageway.