Experimental study of sacculotomy in endolymphatic hydrops.

Thirty-nine guinea pigs were used for four groups of experiments: 1. sacculotomy only, 2. sacculotomy and simultaneous obliteration of the endolymphatic duct, 3. sacculotomy followed by obliteration of the endolymphatic duct, and 4. obliteration of the endolymphatic duct followed by sacculotomy. Sacculotomy alone caused only minimal cochlear pathology, whereas sacculotomy on hydropic ears produced severe atrophy of the organ of Corti and cochlear neurons as well as connective cells of the limbus. There was histological evidence that Reissner's membrane in hydropic ears was ruptured by the sacculotomy procedure. The primary cause for the severe atrophic changes is thought to be the toxic effect of intermixing perilymph with a large volume of endolymph. The surgically induced saccular tears appeared to be healed in all ears, and the procedure had no significant effect on the course of endolymphatic hydrops. Although two out of eleven specimens in which sacculotomy was performed on hydropic ears showed tears and collapse of Reissner's membrane, since others with similar tears showed extensive hydrops, the possibility of artifact could not be ruled out. In one specimen with simultaneous sacculotomy and obliteration of the duct, persisting fistulae were noted at the sites of accidental fracture of the osseous spiral lamina; this ear is the only one which failed to develop hydrops following obliteration of the duct. The results of this experiment, namely sacculotomy on hydropic guinea pig ears, suggest that sacculotomy is not a rational procedure for the control of endolymphatic hydrops in Ménière's disease for the following reasons: 1. surgically induced tears in the saccular wall are followed by rapid healing and 2. intermixing of perilymph and a large volume of endolymph causes toxic atrophy of the limbus, organ of Corti and cochlear neurons.