Streptomycin Perfusion of the Labyrinth

Abstract

The combination of fluctuant hearing loss, fullness, tinnitus and dizzy spells we call Meniere's disease is thought to be caused by endolymphatic hydrops. Most patients with the clinical picture of Meniere's disease do have endolymphatic hydrops but some patients with endolymphatic hydrops do not have the clinical picture of Meniere's disease. It would appear there is an, as yet unknown, immune-mediated, cause for Meniere's disease, in addition to endolymphatic hydrops, and this immune-mediated cause may aggravate those ears with endolymphatic hydrops. While medical treatment with a low-salt diet, diuretics and steroids are of value in some patients when given early in controlling dizzy spells and improving the hearing, there is usually no real, long-term benefit. Since none of these “shunts” of the sac could remain open for more than a few hours, they could have no more direct benefit than a one-time drainage of endolymph, while doing harm to the fluid absorption, immune response and phagocytosis roles of the endolymphatic sac. The various vestibular neurectomy operations, while usually stopping the dizzy attacks, are both difficult and potentially dangerous, but more important, do nothing for the hearing loss. The one direct attack on the problem, both easy to perform and certain to relieve the dizzy attacks, is to destroy the vestibular receptors with streptomycin. This destructive action on the stereocilia and sensory cells, without damage to the rest of the vestibular system and the cochlea, has been verified by two cat experiments with streptomycin by Norris et al. and Norris & Shea and two guinea pig experiments with gentamicin by Kimura. The bony lateral semicircular canal is exposed and the bone removed with diamond burr with constant irrigation until there is a double blue line over the underlying canal. The strip of bone between the double blue lines is removed with a sharp pick so as not to damage the lateral membranous canal attached to the undersurface of the bone. A 30-gauge needle on a tuberculin syringe is then inserted into the perilymph of the lateral semicircular canal, past the lateral membranous duct, and 0.1 ml of artificial perilymph containing 25 μg of streptomycin/ml is injected slowly. In those ears in which the endolymph pressure is increased, a very small opening is made in the lateral membranous duct with a sharp pick and one or two μl of endolymph are removed with a micropipette. The opening in the bone of the lateral semicirculr canal is then covered with a flat chip of bone with fascia on top to seal the opening in the canal, and the wound closed. Not one patient has had a true dizzy spell from the operated ear after operation, and the caloric response has been eliminated in the operated ear in each one measured. Fullness and tinnitus, except for the ringing due to neural degeneration, are less. Hearing is the same or better in 75%, a little worse in 20% and much worse in 5%.

Key Words:

• streptomycin perfusion
• endolymphatic hydrops
• stereocilia