Surgical observations on the endolymphatic sac in Meniere's disease.

OBJECTIVE: This study aimed to clarify the pathoanatomic characteristics of the endolymphatic sac in Meniere's disease by surgical observations.

STUDY DESIGN: The study design was a retrospective case study conducted in the setting of University Hospital at Shiga University of Medical Science.

PATIENTS: Studied were 101 patients with Meniere's disease who underwent endolymphatic sac drainage surgery at the university hospital by the same surgical team between 1984 and 1995. Control group consisted of 23 patients with non-Meniere's disease.

MAIN OUTCOME MEASURES: Photographs were taken of the sac in 101 patients with Meniere's disease during endolymphatic sac drainage surgery, and the pathoanatomic findings of the sacs were classified into three grades regarding position (types I, II, III), size (large, intermediate, small), color (red, intermediate, white), and vascularity (fair, intermediate, poor). Statistical difference was studied between Meniere's group and non-Meniere's group by chi-square test.

RESULTS: The patients with Meniere's disease were found to have endolymphatic sacs located inferiorly to the posterior semicircular canal, very close to the jugular bulb (type III) (p < 0.001). The sacs also were smaller in size (p = 0.068), whiter in surface color (p = 0.0036, 0.01), and of less vascularity (p = 0.051) than those of the patients with non-Meniere's disease. The comparisons showed significant differences only in position and color.

CONCLUSION: The patients with Meniere's disease were found to have endolymphatic sacs located inferiorly to the posterior semicircular canal, very close to the jugular bulb. The sacs also were whiter in surface color.