In 2005, it was estimated that nearly 12,800 deaths were associated with malignant tumors of the brain and other parts of the central nervous system.

High-grade gliomas are the most frequent primary brain tumors in adult patients, accounting for 40 percent of all tumors and 78 percent of malignant tumors. In brain tumor surgery, the aim is always to maximize the resection while minimizing the loss of neurological function.

Because of the infiltrating nature of gliomas, it is likely that a portion of the tumor will occupy, or be continuous with, functional brain tissue. Therefore, the need to preserve functions like language function must be balanced with the necessity for maximal tumor resection. Intraoperative language mapping is considered by some as a critically important technique for patients with tumors affecting language function.

One neurosurgeon’s experience with 250 consecutive patients with large, dominant-hemisphere gliomas requiring language mapping was recently analyzed.

The results of this study, the largest patient pool studied to date, "Functional Outcome Following Intraoperative Cortical Stimulation Mapping of Language Sites in 250 Patients with Dominant Hemisphere Gliomas," was presented by Nader Sanai, MD, during the 74th Annual Meeting of the American Association of Neurological Surgeons in San Francisco. Co-authors are G. Evren Keles, MD, Zaman Mirzadeh, BS, and Mitchel S. Berger, MD, FACS.

Intraoperative language mapping involves operating on an awake patient and mapping the anatomy of his or her language function during the operation, are helping surgeons identify which portions of the tumor are safe to resect.

“Despite considerable evidence supporting the use of intraoperative cortical stimulation to map language function, the efficacy of this technique in preserving functional neurological outcome following aggressive glioma resection remains poorly understood,” says Sanai.

In the study of 250 glioma patients undergoing this procedure, the following outcomes were noted:

• Overall, 159 patients, or 63.6 percent, had intact speech preoperatively.
• At one week postoperatively, 194 (77.6 percent) remained at their baseline language function, while 21 (8.4 percent) worsened and 35 (14.0 percent) had new speech deficits.
• By six months, 52 (92.8 percent) of 56 patients with new or worsened language deficits returned to baseline or better, and the remaining four (7.1 percent) had permanent deficits.
• Thus, 1.6 percent of all patients developed permanent postoperative language deficits.

“This series of patients represents the largest study to date examining intraoperative language mapping for gliomas, and supports the use of language mapping as the rule, rather than the exception, for dominant hemisphere gliomas,” says Sanai. “The findings support the conclusion that cortical language mapping may be used as a safe and efficient adjunct to optimize glioma resection while preserving essential language sites."

Source: American Association of Neurological Surgeons (AANS)