Résumé
Despite the use of somatosensory evoked potentials during surgery for spinal cord tumors or vascular lesions, postoperative neurological disorders, particularly motor deficits, frequently occur after aggressive surgery with an attempt of gross total resection. We report the use of peroperative direct spinal cord electrical stimulation to decrease morbidity while improving the quality of resection. Three patients with intramedullary lesions (1 ependymoma and 2 cavernomas), initially revealed by pain and followed by neurological deficit, were operated at our institution using peroperative direct medullary electrical stimulations (60 Hz, biphasic square wave pulses with 1 ms/phase, 0.9 mA) under general anesthesia without curare. In all cases, gross total resection was performed until motor responses to stimulation, which indicated anterior and lateral boundaries between the lesion and the functional tissue, were obtained. There was no postoperative neurological worsening, but an immediate partial improvement of sensory and bladder disorders in the patient with ependymoma. Postoperative MRI confirmed total resection in the 3 patients. These cases demonstrate that direct medullary electrical stimulation is a safe, easy, precise and reliable method to reduce morbidity during spinal cord surgery.