Stereotactic neurosurgery: new aspects of an old method.

Seventy-seven patients underwent 93 stereotactic operations during a five-year period 1980-1984 at the Department of Neurosurgery, Oulu University Central Hospital, Oulu, Finland. Thirty patients were cases of general neurosurgery, consisting of 27 stereotactic biopsies of deep-seated brain tumors with a diagnostic accuracy of 89% (24/27), and three evacuation-aspiration procedures. Two-thirds of the operations (63/93) belonged to the field of functional neurosurgery, the most frequent procedure being stereotactic ventrolateral thalamotomy. In the treatment of drug resistant Parkinsonian tremor and rigidity the success rate was 70% in bilateral and over 90% in unilateral procedures. Operative mortality was 1.1% (1/93 operations) and morbidity 3.2%. Stereotactic technique is mandatory for diagnostic biopsies of deep-seated cerebral lesions. Its combination with computerized tomography ensures better resolution of the lesions and enables more radical therapeutic procedures to be undertaken. Furthermore, stereotactic operations are still indicated in selected cases of medically refractory disorders, especially in epilepsy and involuntary movement disorders.