I have acoustic neuroma treated with radiation in 2003 that has shrunk tumor 40 per cent. still have balance problems. it was suggested i consider having a shot of gentomycin in affected ear to kill nerve. any experience?

Complex decision: Whether or not ablation of your vestibular nerve (8th cranial nerve) will help with your balance problem depends on the cause (EG, size and location of the original tumor). Need a repeat CT/MRI to ensure no regrowth. Additional radiation may help if the tumor has grown. If the cerebellum isn't affected, and if you have no hearing, nerve ablation may a reasonable option. Try Semmes-Murphey neurosrg

Not a panacea: Most patients with acoustic neuroma do well with treatment; unfortunately, that doesn't seem to be the case here. More details need to be outlined here - radiation fields, history of neurofibromatosis, degree of vertigo (assuming this is the cause of the balance problems) etc. Your treatment team should include an radiation oncologist, ENT surgeon, neurologist and neurosurgeon to help recommend.