Electrical alternative to pulsed fiber-delivered lasers in microsurgery

Abstract

An electrical system based on a tapered microelectrode has been developed for generation of high voltage sub-microsecond discharge in physiological medium. Different types of the resulting pulses of current are investigated as well as the dynamics of the associated cavitation bubbles. A highly localized zone of power dissipation - about 20 μm in size - results in a low threshold energy of cavitation bubble generation - about 3 μJ - in comparison to laser-based intraocular microsurgical instrumentation with fiber delivery systems. Cavitation bubble dynamics resulting from the electric discharge is similar to that observed with ns-pulsed fiber-delivered lasers in strongly absorbing liquid medium. Efficiency of the pulse energy conversion to the bubble energy is about 12%, which is lower than the best results obtained with lasers. In spite of that, due to the low threshold energy, cavitation bubbles required for effective cutting of soft tissue can be generated at energies lower than that used in laser instrumentation with fiber-based delivery systems. The proposed device has a potential to become a convenient and a cost-effective alternative to such lasers in vitreoretinal microsurgery. © 1997 American Institute of Physics.