Strategy of Surgical Resection for Glioma Based on Intraoperative Functional Mapping and Monitoring

A growing number of papers have pointed out the relationship between aggressive resection of gliomas and survival prognosis. For maximum resection, the current concept of surgical decision-making is in “information-guided surgery” using multimodal intraoperative information. With this, anatomical information from intraoperative magnetic resonance imaging (MRI) and navigation, functional information from brain mapping and monitoring, and histopathological information must all be taken into account in the new perspective for innovative minimally invasive surgical treatment of glioma. Intraoperative neurofunctional information such as neurophysiological functional monitoring takes the most important part in the process to acquire objective visual data during tumor removal and to integrate these findings as digitized data for intraoperative surgical decision-making. Moreover, the analysis of qualitative data and threshold-setting for quantitative data raise difficult issues in the interpretation and processing of each data type, such as determination of motor evoked potential (MEP) decline, underestimation in tractography, and judgments of patient response for neurofunctional mapping and monitoring during awake craniotomy. Neurofunctional diagnosis of false-positives in these situations may affect the extent of resection, while false-negatives influence intra- and postoperative complication rates. Additionally, even though the various intraoperative visualized data from multiple sources contribute significantly to the reliability of surgical decisions when the information is integrated and provided, it is not uncommon for individual pieces of information to convey opposing suggestions. Such conflicting pieces of information facilitate higher-order decision-making that is dependent on the policies of the facility and the priorities of the patient, as well as the availability of the histopathological characteristics from resected tissue.

Selective excision of metastatic brain tumors originating in the motor cortex with preservation of function

PURPOSE

Brain metastases are common in patients with cancer and can cause considerable morbidity or death. Metastasis in eloquent areas of the brain, particularly the primary motor cortex, may present significant treatment challenges.

PATIENTS AND METHODS

Seventeen consecutive patients with metastasis within the primary motor cortex underwent selective microsurgical tumor resection. Operative, hospital, neuroimaging, and follow-up information was reviewed.

RESULTS

There were 10 women and seven men (mean age, 54.3 years) who underwent 17 operations for symptomatic brain metastases. Motor cortex was identified and tumor (mean volume, 10.2 cm(3)) was completely resected in all patients. Three patients had transient or reversible complications. Karnofsky performance scores improved in 16 of 17 patients at 4 weeks postoperatively, with a mean improvement of 1.8 grades compared with preoperative scores (P < .05). Overall survival of 16 patients with distant follow-up (> 6 months or until death) averaged 10.6 +/- 4.4 months, with nine of 16 (56%) assessable patients surviving 1 year or longer. Survival of these 16 patients, by recursive partitioning analysis (RPA), was 11.2, 13.3, and 6.7 months for RPA classes I, II, and III, respectively. The cause of death in 14 of 15 patients who have died was progressive systemic disease; in one patient it was a combination of systemic and distant CNS disease progression. There were no local CNS recurrences.

CONCLUSION

Complete microsurgical resection of metastatic tumors in the primary motor cortex is feasible and efficacious, results in a sustained improvement in performance outcomes, and permits satisfactory long-term survival.