Trigeminal neurinomas. A series of 111 surgical cases from a single institution.

Neurinomas arising from the trigeminal nerve are rare (0.1-0.4% of intracranial tumours: 1-8% of all intracranial neurinomas). A series of 111 trigeminal neurinomas operated on at the Institute of Neurosurgery "N. N. Burdenko" of Moscow, Russia, during the period 1961-1994 is presented. Clinical features, diagnostic radiology, surgery and results of treatment are discussed. We distinguished four groups of trigeminal neurinomas: a) Posterior fossa tumours; b) Tumours of the Gasserian ganglion; c) "Dumb-bell" supra-subtentorial tumours; d) Neurinomas of the peripheral branches. The complex clinical symptomatology is related to the actual location of the lesion. Surgery of trigeminal neurinomas may be very difficult, particularly in cases of dump-bell supra-subtentorial lesions. In this series, 3 cases died postoperatively. Out of the 108 patients surviving surgery, long-term follow-up (min. 13 months, max. 33 years, average 13.5 years) was available in 98 cases. 84 patients (86.7%) showed good-to excellent results, with partial trigeminal deficit as the only surgical sequela. 13 patients (11.7%) had a symptomatic recurrence following incomplete tumour removal. Second surgery, ranging from 1.4 to 9 years (average 3.8 years) following the first operation, was judged radical in 9 cases (69.2), however, the rate of complications of repeated surgery was higher than that occurring after the first operation. The advent of microsurgery, together with the introduction of the techniques of skull base surgery and of modern diagnostic imaging tools, have improved surgical results in terms of increased radicality and reduced complications.