P12.01 * SURGERY WITH INTRA-OPERATIVE NEUROPHYSIOLOGICAL MONITORING IN THE MANAGEMENT OF THALAMIC ASTROCYTOMAS

Abstract

INTRODUCTION: The thalamus is a deep-seated and crucial structure for the sensory-motor system. It has been longly considered a surgically inaccessible area due to themorbidity associated with surgical resections. In fact, astrocytomas of the thalamus usually undergo bioptic procedures followed by adjuvant treatments (if indicated). Intra-operative neurophysiological monitoring (IONM) allows safe and satisfactory resections of lobar gliomas. Considering the need of reliable specimens for the pathological diagnosis and that the extent of resection is positively associated with overall survival, aim of this study was to review the feasibility and outcome of a small series of patients with thalamic astrocytomas operated with the aid of IONM. PATIENTS AND METHODS: Five patients with thalamic astrocytomas (1 grade I, 3 grade III, 1 grade IV) underwent surgical resection with IONM. Two astrocytomas were in the dominant hemisphere. All patients performed pre-operative and post-operative neuropsychological assessment.IONMconsisted in transcranial MEP monitoring (4 patients), cortical MEP monitoring (2 patients), direct electrical stimulation (5 patients), EEG (5 patients) and ECoG monitoring (2 patients). Anesthesia was totally intra-venous (propofol + remifentanyl) for all patients; 1 patients was operated following an asleep-awake protocol, 4 following an asleep-asleep protocol. RESULTS: Noneof patients suffered from permanentmotor deficits; 2patients had a transient hemiparesis requiring rehabilitation; 1 patient suffered a transient aphasia, and 1 patient had permanent aphasia. None of the patients had intraoperative seizures, but 1 patient had a post-operative transient status epilepticus. Resection was total or subtotal in 3 cases and partial (with resection between 50 and 80% of the tumor volume) in the other 2 cases. CONCLUSIONS:Surgical resection of thalamic astrocytomas could be meaningful and relatively safe when guided by IONM. Larger series of patients are required to confirm this preliminary data.