Principles of Supplemental Motor Area and Cingulate Tumor Resection With Asleep Trimodal Motor Mapping: 2-Dimensional...

Resection of intra-axial tumors adjacent to the motor pathways can lead to devastating deficits; however, with an appropriate mapping technique, it can be performed safely. We present the case of a 63-yr-old woman with a diffuse glioma centered in the left supplemental motor area (SMA) and extending throughout the cingulate gyrus. In the video, we demonstrate the principles developed by the senior author for trimodal motor mapping under general anesthesia. Trimodal motor mapping includes direct stimulation of the cortex with a strip electrode, use of the bipolar stimulator for cortical and subcortical mapping, and use of the monopolar stimulator for subcortical motor mapping. We highlight technical principles required to safely resect these tumors, including the key anatomic landmarks and approach to SMA/cingulate lesions, techniques for subpial dissection, and preservation of en passage vessels. Patients with SMA tumors will almost always have a deficit after SMA resection, but if motor pathways are preserved and can be stimulated to produce movement at the end of the case, then the deficit will almost always improve, as was the case with this patient. Initially, postoperatively, she was nonverbal and hemiplegic, but by postoperative day 7 she recovered her speech significantly, was naming three of three objects, and was moving her right side. By 6 wk postoperative, she was ambulating independently and had normal speech. This case demonstrates the principles and techniques necessary for achieving maximal safe resection of tumors adjacent to the motor pathways with the patient under general anesthesia. The patient gave written informed consent for the surgical resection of her tumor and for the publication of this video.