Partitioning the labyrinth to preserve hearing during partial labyrinthectomy

Three authors have reported hearing preservation after resecting semicircular canals during the extirpation of temporal bone, cerebellopontine, and skull base tumors. The use of the CO2, KTP, and argon lasers to partition the labyrinth before and during these procedures is discussed. Laser partitioning of the membranous semicircular canal can be done during a primary surgery, after bluelining the bony semicircular canal at the point of desired transection but before opening the labyrinth. This membranous partitioning will keep the endolymphatic compartment intact. Fibrosis of the bony semicircular canal requires a higher laser energy to be applied to the area at which the semicircular canal is to be transected than the laser energy necessary for membranous partitioning. It also requires 8 to 12 weeks for fibrous occlusion of the bony semicircular canal to occur before the semicircular canal resection can be done with hearing preservation.