FLEXIBLE FIBEROPTIC ENDOSCOPY AND LASER-SURGERY IN OBLITERATED COCHLEAS - HUMAN TEMPORAL BONE STUDIES

Background and Objective: The use of conventional drilling procedures in cochlear implant surgery of ossified cochleae poses special risks t o the facial nerve and the carotid artery. This study evaluated the al ternate use of flexible fiberoptic endoscopy and mid-infrared laser su rgery for recanalization of partially and artificially obliterated coc hleae in freshly dissected human cadavers. Study Design/Materials and Methods: A pulsed Holmium:YAG-laser (lambda = 2120 nm) was used in the free-running mode (1180 mJ, 250 mu s pulse, 5 Hz). A 660 mu m optic q uartz fiber was positioned in the center of the round window niche and slowly-endoscopically guided-advanced in contact shooting over 1.5 cm , creating by vaporization and photoablation a passage through the art ificial bony occlusion in the basal segment of the cochlea. Results: I n all experiments, laser application (110-130 pulses) resulted in comp lete recanalization of the bony occlusions without damaging surroundin g structures, The microendoscopy proved capable of guiding the laser f iber through the curved segment of the basal turn allowing identificat ion of normal bone, bone cement, and laser-treated bone cement. Conclu sion: If partial ossification of the basal turn is present, this techn ique could give access to place analog as well as digital implants dee p within the cochlea. (C) 1996 Wiley-Liss, Inc.