• This study describes the technique and instrumentation necessary to perform a double-wall biopsy of the endolymphatic sac (ELS). Since this technique protects the lumen of the ELS, which is within the center of the biopsy sample surrounded by the lateral and medial wall, the ultrastructure of the ELS epithelium, luminal contents, and perisaccular connective tissue tends to represent the in vivo status. The biopsy specimen can be analyzed by electron microscopy for clinical-pathologic correlation. Ultrastructural analysis (1) provides definite identification of the ELS and epithelium, (2) may provide insight into a possible role of the ELS in the pathogenesis of endolymphatic hydrops, and (3) can provide much improved clinical-pathologic correlation over only light microscopic studies.
(Arch Otolaryngol 1982;108:292-298)