Two patients experienced sensorineural hearing losses for different reasons following stapedectomy. One had an immediate severe sensorineural hearing loss following a fat-wire implant. Postmortem histologic study revealed severe cochlear degeneration, presumably caused by necrosis of the fat graft. The other patient experienced progressive fluctuating sensorineural hearing loss and vertigo several years after the introduction of the Teflon-wire prosthesis. Postmortem histologic study of this ear showed that the prosthesis had impaled the saccule, causing collapse of its wall with subsequent cochlear endolymphatic hydrops. These findings underscore the importance of atraumatic surgical technique in the performance of successful stapedectomy.