Speech Disturbance during Subcortical Mapping in Surgery for Right Superior Frontal Gyrus Glioma in Awake Patient

• Published in: Journal of Neurological Surgery Part A: Central European Neurosurgery
• Main Authors: Šumonja, I., Sajko, T., Rotim, K., Zmajević, M., Mladić-Batinica, I.
• Format: Conference Proceeding
• Language: English
• Published: 19.10.2015
• ISSN: 2193-6315; 2193-6323
• DOI: 10.1055/s-0035-1566438

Introduction Preservation of functional cortex and subcortical tracts is of most importance in resection of low-grade gliomas located in the eloquent regions of the brain. Recently, tractography and fiber dissection confirmed a connection between supplementary motor area (SMA) of superior frontal gyrus and posterior Broca region, called the frontal aslant tract, which is found left lateralized. Injury to the subcortical structures in the area can cause aphasia similar to damage to supplementary motor area. Case Presentation Case report of a right handed patient undergoing awake surgery for a low-grade glioma located in right superior frontal gyrus is presented. Owing to technical reasons (lack of fMRI and tractography), preoperative evaluation of language dominant hemisphere and fiber visualization could not be performed. During the surgery, cortical mapping was performed to find precentral, postcentral, and superior frontal gyrus. After tumor removal in superior frontal gyrus, subcortical stimulation of the lateral wall of tumor resection cavity was performed, during which speech disturbance as motor dysphasia and low speech initiation were noticed. The tumor was removed successfully without postoperative language disturbances. Conclusion Direct subcortical mapping during awake brain surgery provides an essential tool to investigate the complex language network of the brain and to preserve language function during tumor removal. We must point out that in our case, speech disturbance was noticed during subcortical stimulation of the SMA of the nondominant hemisphere, which furthermore emphasizes the need for intraoperative stimulation during brain surgery. Keywords Low-grade glioma; superior frontal gyrus; awake surgery