gms | German Medical Science

Objective: Tumours in the opercular area of the dominant hemisphere demand special treatment due to the proximity to motor and speech areas. The purpose of this study was to determine the morbidity and to correlate the results with inraoperative monitoring data.

Methods: Eighteen patients with gliomas (WHO II° 7, WHO III°6, WHO IV° 5) in the opercular region treated by surgery were included in this study. The degree of the perioperative speech disturbances was evaluated according to the Aachener Aphasia Test (AAT). Awake craniotomy and intraoperative speech mapping by direct electrical cortical stimulation was performed in all cases. The cortex was stimulated with a bipolar stimulus of 60 Hz with a duration of 2 - 3 sec and maximal intensity of 18 mA. For the intraoperative mapping a modified AAT was applied.

Results: Before operation 9 patients had mild to middle grade speech disturbances. In the first 48 postoperative hours, a deterioration of speech function was observed in 10 of the cases. This however, improved within the first week. At this point speech dysfunction was observed only in 3 of the patients. In 7 patients functionally important stimulation points were overlaying the tumour. Single functional points within the tumour were resected. No statistically significant difference in terms of functional outcome was observed in these patients. Whenever a group of functional cortical points was found, the resection distance was more than 0,5 mm to each point.

Conclusions: Surgery of gliomas within the left opercular area can result in permanent speech dysfunctions. However, intraoperative speech mapping increases the safety and allows a safer “tailored” resection of the tumours. The true functional relevance of single stimulation points remains unclear. In the present study, the resection of these points did not result in permanent postoperative functional deficit.