Unidirectional inner ear valve implant for endolymphatic sac surgery in Meniere's disease.

Abstract

In five patients with long-standing Meniere's disease, a unidirectional inner ear valve was implanted into the endolymphatic sac (ELS) to facilitate removal of excess endolymph in the hydropic state. These patients were all candidates for ablative surgery. They all had intractable vertigo and severe hearing losses. Four out of five patients had positive preoperative glycerol tests. In the patients with positive glycerol tests, the group averages before surgery were as follows: pure-tone average (PTA), 63 dB; speech reception threshold (SRT), 79 dB; and discrimination score, 27%. All of the patients, except a patient with a negative glycerol test, benefited from the surgery, including exceptional hearing improvements, averages of 21 dB in PTA, 30.5 dB in SRT, and 48% in discrimination, which remained so for at least a one-year minimum follow-up. All patients with preoperative positive glycerol tests had a class A result according to the criteria set forth by the American Academy of Ophthalmology and Otolaryngology. The cumulative follow-up exceeded the minimal requirements by a factor of 39 times. The only failure was in a patient with a negative glycerol test, which was predictable. Results of tomography confirmed the correct position of the valve without evidence of migration or extrusion even in the failure. This new valve appears to be a safe and more effective implant than Silastic sheeting alone or any other ELS implant in patients with a positive glycerol test.