RÉSUMÉ
OBJECTIVE: To evaluate the neurological complications after stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT). MATERIAL AND METHOD: The Ramathibodi Radiosurgery Unit started its service in August 1997, using the linear-accelerator based system. There were 144 patients treated from August 1997 to October 1999. Single fraction SRS was performed in 56 cases consisting of 46 arteriovenous malformations (AVMs), 4 cranial nerve (CN) schwannomas, 3 pituitary adenomas, 2 meningiomas, and 1 multiple hemangioblastomas. Eighty eight patients received multifractionated SRT, including 27 meningiomas, 17 pituitary adenomas, 13 benign and malignant gliomas, 8 brain metastasi(e)s, 5 CA nasopharynx, 5 craniopharyngiomas, 5 CN schwannomas, 2 AVMs, 2 chordomas, and 4 others. After treatment the patients were clinically evaluated every 1-6 months and MRI was scheduled at 6 or 12-month interval or when there were abnormal clinical signs/symptoms. The complications included any new neurological complaints or findings during and after treatment. RESULTS: Median follow-up time was 9.5 (0-20) months. Of 138 patients with available follow-up data, there were 23 (13 SRS and 10 SRT) cases who experienced new neurological symptoms at 3 weeks - 20 months (median = 3 months) from the time treatment started. Symptoms included headache, seizure, weakness, decreased vision, vertigo with/without ataxia, diplopia, dizziness, impaired memory, hemifacial spasm, decreased sensation and facial palsy. Three AVM patients had intraventricular hemorrhage from the patent nidi. After symptomatic treatment there were 15 cases with complete recovery (including seizure control) and 6 with partial recovery. There were 2 deaths from ruptured AVM and progressive metastatic brain lesion. There were 79 patients who had at least 1 follow-up MRI, and changes were detected in T2-weighted images in 19 cases at 3-18 months after treatment. Ten cases had symptoms corresponding to the image changes, the other 9 patients were asymptomatic. CONCLUSIONS: Longer follow-up time is needed to fully evaluate the complications after SRS/SRT, however, preliminary results showed that most of the complications were mild and transient. There was a tendency of a higher complication rate in the SRS group. Not all patients with post treatment image changes developed symptoms.