Connectome imaging to facilitate preservation of the frontal aslant tract

Supplementary motor area (SMA) syndrome is characterized by contralateral akinesia and mutism, and frequently occurs following resection of tumors involving the superior frontal gyrus. The frontal aslant tract (FAT), involved in functional connectivity of the supplementary area and other related large-scale brain networks, is implicated in the pathogenesis of, and recovery from, SMA syndrome. However, intraoperative neuromonitoring of the FAT is inconsistent and poorly reproducible, leading to a high rate of postoperative SMA syndrome. We report the cases of two patients harboring lesions of the superior frontal gyrus: one cavernoma and one low grade glioma. Connectome imaging revealed involvement of functional networks implicated in SMA syndrome, as well as displacement of the FAT. A connectome-guided awake craniotomy was performed in both cases, and a combinatorial approach using awake language mapping and connectome-imaging guidance facilitated gross total resection of both patient’s lesions without inducing SMA syndrome postoperatively. Functional and structural connectivity imaging through connectomics allows the identification of areas not traditionally considered eloquent, such as the SMA and FAT, and can help facilitate their preservation. Conserving the functional and structural connectivity of broader brain regions that are not traditionally deemed eloquent can improve patient outcomes.