Awake craniotomy for aggressive resection of primary gliomas located in eloquent brain

Objective: To determine with intraoperative neurologic and language examina tions the maximal tumor resection achievable with acceptable postoperative neurologic dysfunction in patients undergoing awake stereotactic glial tumo r resection in eloquent regions of the brain. Patients and Methods: Between October 1995 and December 2000, 65 patients u nderwent frameless stereotactic resection of glial tumors located in functi oning tissue. During the resection, continuous examinations by a neurologis t and speech pathologist were performed. The goal of surgery was to resect the maximum neurologically permissible tumor volume defined on preoperative T2 imaging. Tumor resection was stopped at the onset of neurologic dysfunc tion, Novel segmentation software was used to measure tumor cytoreduction b ased on pre- and postoperative magnetic resonance imaging. All patients und erwent 3-month postoperative neurologic examinations to determine functiona l outcomes. Results: The cortical and subcortical white matter tracts at risk for injur y were the left frontal operculum in 15 patients, the central lobule in 38, the insula in 11, and the left angular gyrus in 1, Thirty-four (52%) had a greater than 90% reduction in T2 signal postoperatively. In 26 patients th ought to have low-grade tumors based on preoperative imaging, 12 proved to have grade 3 gliomas, Forty-eight patients (74%) developed intraoperative d eficits; 34 (71%) recovered to a modified Rankin grade of 0 or 1 at 3 month s postoperatively, 11 (23%) achieved a modified Rankin grade of 2, and 3 pa tients (6%) achieved a modified Rankin grade of 3 or 4 at 3-month follow-up . There was no operative mortality; 17 patients (26%) died from tumor progr ession during the follow-up period. Conclusions: Combining frameless computer-guided stereotaxis with cortical stimulation and repetitive neurologic and language assessments facilitates tumor resection in functioning brain regions. Resecting tumor until the ons et of neurologic deficits allows for a good functional recovery. Imaging so ftware can objectively and accurately measure preoperative and postoperativ e tumor volumes.