Effects of cochlear drilling with Piezosurgery Medical device in rats 1

Objectives/Hypothesis: Drilling on the otic capsule for cochleostomy should be less traumatic to the cochlea with the Piezosurgery Medical device (PZ) than with a standard diamond drill (DD). "Soft" cochleostomy is used for preservation of residual hearing in cochlear implant patients. PZ drilling can be used for accurate cochleostomy placement with minimal soft-tissue damage and may be superior for atraumatic drilling on the cochlea, as compared with a DD. This study compared inner ear effects after drilling the rat otic capsule with the PZ versus the DD. Study Design: Prospective animal study using rats. Methods: Otic capsule drilling was performed on the left ear with the DD (n = 5) or the PZ (n = 5), while otic capsule temperature was monitored. Contralateral ears served as controls. The animals were sacrificed after 1 week. Organ of Corti damage was morphologically evaluated and compared between groups. Results: Basal turn hair cell loss was observed in all ears in the PZ group, regardless of drilling depth. However, no cochlear damage was found in any ears in the DD group. Conclusions: Otic capsule drilling with the PZ results in greater trauma to the rat inner ear than drilling using conventional methods. Laryngoscope, 2011