Endolymphatic hydrops in guinea pigs after cauterizing the sac with silver nitrate

There have been several reports of perisaccular fibrosis of the endolymphatic sac in some autopsied cases of Meniere's disease. We attempted to initiate perisaccular fibrosis of the sac in guinea pigs by injecting a small amount of 10% silver nitrate solution that cauterizes the tissue readily to produce scar, ie, fibrosis. Ninety-nine guinea pigs out of 108 (92%) that were treated with silver nitrate showed the endolymphatic hydrops in varied extent, from slight to profound. The extent of hydrops might depend on the extent of destruction of the sac following the cauterization. The lumen of the sac was sometimes occupied with dense fibrous connective tissue with deposition of black-silver particles in it. The silver nitrate injection method is an easy way to produce endolymphatic hydrops in guinea pigs.