![]() ![]() ![]() Accordingly, in the study of Romstöck et al. If the waveform was inverted, the central groove sits between those two locations.Īlthough SSEP has now been a routinely used technique with high accuracy to locate the central trench, SSEP phase reversal technology has some unresolved issues in the resection of glioma with particular structures and features. Afterward, in order to determine the structural position according to the direction of waveform, the electrode of N20 is set representing the position of postcentral gyrus and that of P22 representing the precentral gyrus. Stimulating electrodes are deployed near the median nerve or posterior tibial nerve on the opposite side of the tumor to obtain a stable SSEP. Here is the operational procedure of SSEP.Īfter opening the dura mater, a strip electrode is placed vertically in the central sulcus as the recording electrode. Nowadays, phase reversal of SSEP acts as one of the valid parameters for central sulcus positioning throughout the tumor resections ( 10). In the 1970s, SSEP was also a new tool to determine the location of the central sulcus in epilepsy treatment ( 9). With the development of technology and equipment, SSEP is now applicable for majority of neurological and vascular surgeries that may cause neurological injury. Since last century, SSEP has been widely used to predict brain injury in the process of spinal cord surgery, such as regional ischemia ( 8). Intraoperative Neuromonitoring Techniques in the Resection of Gliomas Involving Eloquent Areas Somatosensory Evoked Potential The brief description of intraoperative neuromonitoring techniques are shown in Table 1. Among them, DES has been regarded as the gold standard for real-time detection of the brain function in glioma resection. The IONM technologies currently adopted for gliomas involving eloquent areas include somatosensory evoked potential (SSEP), direct electrical stimulation (DES), motor evoked potentials (MEP), electromyography (EMG), and electrocorticography (ECoG). Therefore, as a unique intuitive technique, intraoperative neuromonitoring (IONM) has become a valid tool for maintaining indispensable neurological function in glioma resection. The brief description of intraoperative imaging techniques is shown in Table 1. Moreover, functional MRI does not distinguish between essential but compensable structures and those having to be retained for functional preservation ( 7). However, DTI cannot display the entire cortico-subcortical circuits, and the accuracy for exhibiting the anatomic regions depends on the fiber tracking software packages employed ( 5, 6). Regarding the technologies for achieving brain mapping, intraoperative functional neuronavigations are commonly applied in glioma resection, which combine with preoperative functional MRI ( 3, 4) to determine the brain functional localization. As a result, for surgery of gliomas involving eloquent areas, tumor boundary identification is not enough accurate brain mapping is also highly recommended. However, iMRI failed to lower the incidence of postoperative neurological dysfunction (PND) in this study ( 2). showed that 96% patients receiving iMRI got 100% tumor EOR compared with the 68% in the control group. Moreover, a clinical trial by Senft et al. In a previous study, the results showed that the combination of 5-ALA and contrast-enhanced ultrasound significantly improved the EOR compared with conventional strategy (median EOR%, 100 vs. Over the past few decades, intraoperative neuronavigation using magnetic resonance imaging (MRI), fluorescence imaging, and ultrasonography have been demonstrated as effective techniques in detecting tumor boundaries. For this reason, relevant assistive technologies have been introduced. As surgical operations are often accompanied by the risk of instant acute partial injuries to eloquent areas, the balance between maximal extent of resection (EOR) and neurological protection is always unmanageable. Surgical resection of gliomas involving eloquent areas has been a real challenge in glioma treatment. Gliomas involving eloquent areas present a specific subtype of gliomas, invading the cortex or subcortical structures associated with sensory, motor, language, and cognitive functions. For gliomas involving eloquent areas, the latter may be particularly important. Among these treatments, a generally accepted goal of glioma surgery is to achieve maximal safe resection, which reflects the need for both prolonging life and protecting neurological function. Currently, an optimal management of glioma requires a multidisciplinary approach including surgery, radiotherapy, chemotherapy, and supportive care. It generally originates from glial or precursor cells and can be characterized by complex genetic background and dismal prognosis. Glioma is the most common type of primary intracranial tumors and accounts for ~30% of them. ![]()
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