Intraoperative direct electrocortical stimulation for glioma surgery [Neurosurgery Wiki]

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====== Intraoperative direct electrocortical stimulation for glioma surgery ======

see also [[Awake surgery for glioma]].

see also [[Resting-state functional magnetic resonance for glioma surgery]].
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[[Stimulation]]-induced [[seizure]]s (SISs) are rare but serious events during [[electrocortical stimulation]] (ECS) [[mapping]]. SISs are most common when [[mapping]] the [[frontal lobe]]. Greater [[stimulation current]] is not associated with the identification of more cortical functional sites during [[glioma surgery]]
((Muster RH, Young JS, Woo PYM, Morshed RA, Warrier G, Kakaizada S, Molinaro AM, Berger MS, Hervey-Jumper SL. The Relationship Between [[Stimulation Current]] and [[Functional]] Site [[Localization]] During [[Brain Mapping]]. Neurosurgery. 2021 May 13;88(6):1043-1050. doi: 10.1093/neuros/nyaa364. PMID: 33289525; PMCID: PMC8117445.)).
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[[Glioma surgery]] represents a significant advance with respect to improving [[resection]] rates using new surgical techniques, including intraoperative [[functional mapping]], [[monitoring]], and [[imaging]]. Functional mapping under [[awake craniotomy]] can be used to detect individual [[eloquent]] tissues of [[speech]] and/or [[motor]] functions in order to prevent unexpected [[deficit]]s and promote extensive [[resection]]. In addition, monitoring the patient’s neurological findings during resection is also very useful for maximizing the removal rate and minimizing deficits by alarming that the touched area is close to eloquent regions and fibers. Assessing several types of [[evoked potential]]s, including [[motor evoked potential]]s (MEPs), [[sensory evoked potentials]] (SEPs), and [[visual evoked potentials]] (VEPs), is also helpful for performing surgical monitoring in patients under [[general anesthesia]] (GA)
((Saito T, Muragaki Y, Maruyama T, Tamura M, Nitta M, Okada Y. Intraoperative Functional Mapping and Monitoring during Glioma Surgery. Neurol Med Chir (Tokyo). 2015;55 Suppl 1:1-13. PMID: 26236798.)).
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The greater [[extent of resection]] (EOR) of [[low-grade glioma]]s is associated with improved [[survival]]. Proximity to [[eloquent]] cortical regions often limits resectability and elevates the risk of surgery-related deficits. Therefore, functional localization of eloquent cortex or subcortical [[fiber tract]]s can enhance the [[EOR]] and [[functional outcome]]. [[Imaging]] techniques such as [[functional MRI]] and [[diffusion tensor imaging]] [[fiber tracking]], and neurophysiological methods like navigated [[transcranial magnetic stimulation]] and [[magnetoencephalography]], make it possible to identify eloquent areas prior to resective surgery and to tailor indication and surgical [[approach]] but also to assess the surgical [[risk]]. Intraoperative monitoring with [[direct cortical stimulation]] and subcortical stimulation enables surgeons to preserve essential functional tissue during surgery. Through tailored, pre-and intraoperative mapping and monitoring the EOR can be maximized, with reduced rates of surgery-related deficits
((Ottenhausen M, Krieg SM, Meyer B, Ringel F. Functional preoperative and intraoperative mapping and monitoring: increasing safety and efficacy in [[glioma surgery]]. Neurosurg Focus. 2015 Jan;38(1):E3. doi: 10.3171/2014.10.FOCUS14611. PMID: 25552283.)).
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As the most accurate and reliable method of brain functional area positioning, [[Intraoperative direct electrocortical stimulation]] is able to determine in real-time the parts of the brain necessary for such functions as [[movement]], [[sensation]], [[language]], and even [[memory]]. A [[meta-analysis]] suggested that it could also improve the degree of [[resection]] of [[glioma]] while reducing the incidence of permanent neurological dysfunction
((De Witt Hamer PC, Robles SG, Zwinderman AH, Duffau H, Berger MS. Impact of intraoperative stimulation brain mapping on glioma surgery outcome: a meta-analysis. J Clin Oncol. 2012;30:2559–2565. doi: 10.1200/JCO.2011.38.4818.)).
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Findings suggest that surgeons using Intraoperative direct electrocortical stimulation and awake craniotomy during their resections of [[high-grade glioma]] in [[eloquent area]]s experienced better surgical [[outcome]]s: a significantly longer overall postoperative survival, a lower rate of postoperative complications, and a higher percentage of GTR
((Gerritsen JKW, Arends L, Klimek M, Dirven CMF, Vincent AJE. Impact of intraoperative stimulation mapping on high-grade glioma surgery outcome: a meta-analysis. Acta Neurochir (Wien). 2019 Jan;161(1):99-107. doi: 10.1007/s00701-018-3732-4. Epub 2018 Nov 21. PMID: 30465276; PMCID: PMC6331492.)).
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[[Resting-state functional magnetic resonance imaging]] likely reflects similar neural information as detected with [[intraoperative direct electrocortical stimulation]] (DES), but in its current form does not reach the [[spatial resolution]] of DES.
((van Lieshout J, Debaene W, Rapp M, Noordmans HJ, Rutten GJ. fMRI Resting-State Connectivity between Language and Nonlanguage Areas as Defined by Intraoperative Electrocortical Stimulation in Low-Grade Glioma Patients. J Neurol Surg A Cent Eur Neurosurg. 2021 Feb 22. doi: 10.1055/s-0040-1721757. Epub ahead of print. PMID: 33618418.)).

===== References =====