The Effect of Experimental Endolymphatic Hydrops (ELH) on the Endolymphatic Sac (ELS) in the Lemon Shark: An SEM Study

Abstract

The role of the endolymphatic sac (ELS) in the pathogenesis of endolymphatic hydrops (ELH) or Meniere's disease is considered of great importance. An experimental model of ELH, the histopathologic correlate of Meniere's disease, has been utilized to study the effect of excess endolymph and endolymphatic hypertension on the inner ear of the lemon shark (Negation brevirostris). This study investigates the changes which occur to the ELS when the ELH is produced either by cautery of the external endolymphatic duct (ELD) orifice or by ligature of the external ELD after 6 weeks to 6 months postoperatively. All specimens (n = 4 normal n = 6 cautery hydrops, n = 4 ligature hydrops) were routinely prepared for SEM by the critical point method of Smith and Finke and photographed at 20 KV on a Cambridge Stereoscan Mark II. The normal intermediate portion of the ELS shows multiple rugae or folds and true villi (Fig. 1) to increase surface area for the resorbtion of endolymph.