Early and late histologic effects of stereotactic neurosurgery.

The histologic lesions produced in the brain by stereotactic chemosurgery and cryosurgery are reviewed in four patients who died from 25 days to 15 years postoperatively. Three of four patients had damage to the internal capsule and died of pulmonary emboli. The early lesions are histologically nonspecific, but the old lesions of chemopallidectomy and chemothalamectomy in one patient contained metaplastic bone. Lesions produced by freezing are more discrete than those made by chemical means.