Presumably, the intervals between sessions allow the nerve to repair some of the damage it incurred from the radiation, Golby said. The team reported its findings in the December issue of Neurosurgery. Though benign, vestibular schwannomas can sprawl until they cause paralysis, breathing problems and even death. The tumors start within a pinhole-sized canal just inside the inner ear, but they can expand to involve the junction of the brain stem and cerebellum. Early symptoms like hearing loss and vertigo result when the tumor squeezes the nerve that relays impulses from the inner ear to the brain.
Larger tumors can compress the brain itself.
Surgery and a single, focused dose of radiation, the two standard treatments for vestibular schwannoma, both have drawbacks. Removing the tumor demands hours of painstaking and difficult work, a challenge for even the most dexterous neurosurgeons, said Golby. This kind of brain surgery, in which the skull is sawed open, is also grueling for patients. What's more, Golby added, hearing loss resulting from the surgery is almost universal because disentangling the tumor from the nerves running nearby is extremely difficult. And some patients have suffered facial paralysis or loss of sensation because the nerves that serve the face were harmed during the procedure.