Trigeminal neuralgia and hemifacial spasm are caused by vascular compr
ession of the cranial nerves at the brainstem in the majority of cases
. Trigeminal neuralgia occurring in 3.3% of acoustic neurinomas is usu
ally assumed to be a sign of large tumour size; if associated with sma
ll tumour size, an additional pathology, such as typical vascular comp
ression must be suspected and has to be explored at surgery. While fac
ial paresis will usually lead to immediate radiological diagnosis of a
possible cerebellopontine angle (CPA) neoplasm, facial spasm is usual
ly not expected to be associated with a CPA tumour. We report on clini
cal presentation, operative findings, surgical treatment and results i
n 9 cases of small acoustic neurinomas associated with trigeminal neur
algia and on 4 cases associated with hemifacial spasm. The importance
of the clinical characteristics is stressed; if these are typical of a
vascular compression syndrome, further exploration at the time of tum
our surgery and specific treatment by vascular decompression are neces
sary.