Gamma Knife Radiosurgery of Paracentral Epilepsy

Abstract

Background: In pharmacoresistant focal epilepsies involving the central region, risk of motor deficit generally contraindicates cortical resection. Gamma knife radiosurgery (GK) is an established treatment for mesial temporal epilepsy and epilepsy associated with hypothalamic hamartoma. Objectives: To explore the safety profile and efficacy of GK in motor cortex epilepsies. Methods: Four patients (18-31 years) with intractable focal sensorimotor epilepsy seizures arising from the paracentral lobule, demonstrated by stereoelectroencephalography, in whom conventional surgery was contraindicated because of motor deficit risk underwent GK. A marginal dose of 24 Gy was delivered to a focal zone involving the paracentral lobule. Results Volume of treatment ranged from 1.6 to 3.18 cm³ (median: 2.34). No motor deficit or other adverse effect occurred. Follow-up was available for at least 3 years (range: 36-78 months; median: 49). No complication of GK, including motor deficit, occurred. Two patients achieved an Engel class 1B outcome and 2 were unchanged. Both of the patients who improved had gradual disappearance of objective motor ictal semiology (6-12 months after GK), preceding reduced seizure frequency (12-18 months onwards). Cerebral MRI showed no change. Conclusions: GK is a potentially useful treatment for focal paracentral epilepsies where conventional surgery would carry an unacceptable risk of motor deficit.