Abstract
Pre-operatively, it is frequently difficult to differentiate between the various types of abnormal tone in hemiparetic patients. In a series of four hundred patients suffering from hemiparesis secondary to cerebrovascular disease and traumatic encephalopathy, the possibility of using surgery under local anesthesia to augment the pre-operative evaluation was explored. The use of local anesthesia permitted a continuing intra-operative neurological evaluation of residual reflex and motor function after each overactive tendon was lengthened. The value of such examination was further augmented by careful observation of the patient's ability to activate the paretic agonists after each procedure. It became apparent that the individual abnormal components of spasticity, focal or unilateral dystonia, mixed spasticity/dystonia, and rigidity could be more readily identified by this kinetic approach, thus providing a more appropriate surgical means of correction. Clearly, this method produced a better functional outcome in these patients than had been reported in our earlier patients whose surgery had been performed under general anesthesia, and based solely on pre-operative evaluation. Diagnostic methods found to be most reliable in prognosis before and during surgery were those of careful grading of reflexes and the use of associated movements to augment "occult" active power in paretic agonists after selective tendon lengthening.