Preserving the Membranous Labyrinth With a Piezoelectric Drill? Exploring Potential for Semicircular Canal Surgery

HYPOTHESIS: A piezoelectric drill can fenestrate semicircular canals while preserving the membranous labyrinth. BACKGROUND: Semicircular canal surgery carries a high risk of impairing auditory and vestibular function, limiting potential benefit to a small subset of patients. A piezoelectric drill might selectively disintegrate bone while sparing the membranous labyrinth and its endolymphatic compartment. Such selectivity could be particularly advantageous for patients who may benefit from vestibular implantation or semicircular canal plugging but have functional hearing and/or vestibular function. METHODS: Formalin-fixed human temporal bones were included after skeletonizing ('bluelining') the semicircular canals. A piezoelectric drill with an oval-shaped osteoplasty insert was then used to drill 2 fenestrations in each semicircular canal. These locations were cleaned, and the integrity of the membranous labyrinth was assessed at each fenestration site with a surgical microscope. RESULTS: In total, 60 fenestrations were made in 30 semicircular canals from 10 temporal bones. The membranous labyrinth was intact at all these fenestration sites. CONCLUSION: Piezoelectric surgery appears feasible for consistently fenestrating the semicircular canals while preserving the membranous labyrinth. It may enable safer semicircular canal procedures, such as vestibular implantation, in patients with residual inner ear function.