Penfield could develop many types of stimulators to safely stimulate the motor, sensory, auditory, visual, and speech centers. Later, Broadmann and Von Economo could make maps of the cerebral cortex. Bartholow used Faradic current over the cortex and noticed contralateral movement but unfortunately his patient died from seizures. The idea of intraoperative cortical mapping started when Dr. However, surgery depending on preoperative localization of eloquent areas alone carries significant morbidity. New MRI modalities like DTI (diffusion tensor imaging) tractography, BOLD (blood oxygen level dependent) signal changes, and magnetoencephalography can be used preoperatively to determine eloquent brain areas and their relation to brain tumors. This augmented the need of determining these eloquent areas and their relation to brain tumors case by case in order to have safe and effective surgery. Also, the functional brain areas are not anatomically the same in all people and can be displaced by tumors or surrounding edema. The idea to operate on brain tumors under local anesthesia came from knowing that the brain is a nonsensitive structure in spite of controlling the whole process of pain sensation. Surgery of brain tumors near eloquent areas may carry risk of neurological deficit or at least may limit the amount of tumor resection with bad prognostic effect in both situations. Operating on tumors near eloquent brain areas under scalp block and continuous neurological examination during tumor resection proved to be effective in early detection and prevention of permanent major deficits especially in the developing countries with limited resources. Two patients suffered from intraoperative seizures and conversion to general anesthesia was required in one patient. Gross or near total resection was achieved in 15cases, four cases had subtotal resection and biopsy only was done in 1 case. Tumors were related to motor cortex in 11 patients and to language areas in 9 patients. Forty percent of patients were presented by motor weakness. There were 12 males and 8 females with mean age 36.8 years. This work aims to evaluate safety, feasibility, and outcome of operating on patients with space occupying lesions near eloquent areas under scalp block being continuously examined by a neurologist through retrospective study of 20 cases with supratentorial lesions related to language or sensorimotor cortex. However, it requires certain anesthetic drugs, advanced techniques, and trained teams that are not available in every neurosurgical institute. Awake surgery is the gold standard procedure for such lesions. All rights reserved.Surgery of the brain tumors near eloquent areas carries the risk of either disabling neurological deficit or inadequate resection with bad prognosis in both situations. The aim of this review article is not only to pinpoint the major limitations of these methods in order to avoid erroneous conclusions, but also to detail practical aspects associated with the main paradigms routinely used in functional magnetic resonance imaging, and to discuss recent validation of functional magnetic resonance imaging and diffusion tensor imaging results with direct electrical stimulation during awake surgery.ĭiffusion tensor imaging Direct electrostimulation Functional MRI Language cortex Presurgical planning Sensorimotor cortex Visual pathway.Ĭopyright © 2017 Elsevier Masson SAS. Functional magnetic resonance imaging and diffusion tensor imaging are robust methods with increasing indications in neurosurgery for past decade.
Therefore, the precise spatial relationship between the lesion and eloquent brain areas needs to be established. Surgical resection of gliomas involving eloquent brain areas must be maximal in order to improve patients' survival, and safe to prevent postoperative impairments.
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