Tumour-surgery within the central motor strip: surgical results with the aid of electrical motor cortex stimulation.

Surgery of tumours within or close to the central motor area always carries the risk of a new or increased postoperative motor deficit. One reason may be the difficulty of localizing the sensorimotor region, when it is displaced or distorted by the tumour and the perifocal oedema. Recently anatomical data of the craniocerebral topography of the central sulcus became available. We safely used under general anaesthesia the intraoperative mapping of the motor cortex by direct cortical electrical stimulation. In 21 patients tumours adjacent to or within the motor area were microsurgically resected. As a result of intraoperative localization the surgical approach had to be modified in contrast to the preoperative localization of the lesion in 5 patients. No new or increased motor deficit occurred and in some cases the preoperative weakness was reduced remarkably.