Endolymphatic subarachnoid shunt failure caused by Silastic allergy.

During the period from 1964 through 1994, the endolymphatic subarachnoid shunt operation was initially successful in eliminating endolymphatic hydrops and the symptoms and findings it produces in 76% of 645 ears of patients with Meniere's disease. After initial success, lasting from five weeks to nine years, endolymphatic hydrops suddenly returned due to obstruction of the Silastic shunt tube in 11% of patients. In these cases, prompt revision can often restore an initial good result. Histologic and immunologic examination of the material surrounding and occluding the tubes showed an allergic response to the Silastic material in most instances. Efforts to eliminate this cause of failure using a tube of new design and different plastic material are described.