[Microsurgery, laser-assisted cranial nerve anastomosis. An experimental study].

Recently the milliwatt-CO2-laser has been introduced into the armentarium of experimental microsurgery for performing coaptation in peripheral nerves using the thermal effect of laser energy in order to achieve an atraumatic and reliable tissue bond. Experimental studies have shown that laser-assisted nerve coaptation are equal if not superior to conventional techniques in the reduced incidence of neuroma formation as well as the regenerative capacity. In this experimental study we have investigated if the CO2-laser working in the milliwatt range can be successfully applied for performing anastomosis of cranial nerves. The right oculomotor nerve in cats was microsurgically explored along the lateral temporal fossa from its exit at the brain stem to its entrance into the rudimentary cavernous sinus. Following division of the nerve with microscissors the nerve ends were loosely approximated. Thereafter welding of the cut nerves was performed with the CO2-laser (Cooper Laser Sonics, Model 860) using a power of 80-90 milliwatts, a spot-size of 150 microns and single bursts of laser energy. Complete welding of the cut nerve ends took about one to two minutes after which the surgical wound was closed. All experimental animals were observed for a period of 12 weeks after which they were sacrificed and the welded oculomotor nerve was removed for histological examination. Functional recovery of the III. nerve during the observation period was demonstrated by examination of the resting diameter of the pupil as well as by its reaction to direct stimulation with light. Morphological regeneration of the operated nerves could be demonstrated by histological studies.(ABSTRACT TRUNCATED AT 250 WORDS)