Academic Journal
Evidence-based safe stimulation thresholds in subcortical mapping during glioma surgery: a systematic review and meta-analysis.
| Τίτλος: | Evidence-based safe stimulation thresholds in subcortical mapping during glioma surgery: a systematic review and meta-analysis. |
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| Συγγραφείς: | Alsaleh OI; Department of Neurosurgery, Schön Klinik Rendsburg, Rendsburg, Germany. Electronic address: dr.osamaalsaleh@gmail.com., Al Habal SN; Independent Researcher, Rendsburg, Germany., Alomari AML; Department of Neurosurgery, Johannes Wesling Klinikum Minden, Minden, Germany. |
| Πηγή: | Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia [J Clin Neurosci] 2026 Sep; Vol. 151, pp. 112083. Date of Electronic Publication: 2026 May 15. |
| Τύπος έκδοσης: | Journal Article; Systematic Review; Meta-Analysis; Review |
| Γλώσσα: | English |
| Στοιχεία περιοδικού: | Publisher: Churchill Livingstone Country of Publication: Scotland NLM ID: 9433352 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1532-2653 (Electronic) Linking ISSN: 09675868 NLM ISO Abbreviation: J Clin Neurosci Subsets: MEDLINE |
| Imprint Name(s): | Publication: <2000->: Edinburgh : Churchill Livingstone Original Publication: Melbourne, Vic., Australia : Churchill Livingstone, c1994- |
| Ιατρικοί όροι (MeSH): | Glioma*/surgery , Brain Neoplasms*/surgery , Electric Stimulation*/methods , Brain Mapping*/methods , Intraoperative Neurophysiological Monitoring*/methods , Neurosurgical Procedures*/methods, Evoked Potentials, Motor/physiology ; Evidence-Based Medicine/methods ; Humans |
| Περίληψη: | Objective: Intraoperative subcortical electrical stimulation is essential for safe glioma resection near motor pathways, yet minimum safe current thresholds remain controversial, with published recommendations ranging from 1 to 7 mA. This systematic review synthesizes evidence on safe stimulation thresholds in monopolar subcortical mapping during glioma surgery to provide evidence-based recommendations. Methods: Following PRISMA 2020 guidelines, we systematically searched PubMed, Scopus, Web of Science, and Cochrane Library through November 2025 for studies reporting specific threshold values and motor outcomes in glioma surgery with monopolar subcortical monitoring. Study quality was assessed using the Newcastle-Ottawa Scale. Evidence was synthesized narratively and graded using GRADE methodology. Statistical pooling of proportions used random-effects models with Freeman-Tukey double arcsine transformation. Results: Sixteen studies comprising 1,146 patients were included. Safe threshold recommendations ranged from 1 to 7 mA, with 3 mA applied across the largest patient cohort (seven studies, 728 patients, 63.5%). A clear dose-response relationship emerged: pooled permanent motor deficits increased from 2.1% (95% CI 1.3-3.2%) at thresholds ≥5 mA to 17.8% (95% CI 12.4-24.5%) at thresholds <2 mA. Motor evoked potential (MEP) monitoring significantly reduced permanent deficits from 8.7% to 4.0% (pooled OR 0.43, 95% CI 0.26-0.72, p < 0.001). The threshold-distance relationship approximated 1 mA per 1 mm from the corticospinal tract (r = 0.87, p < 0.001). Low-grade gliomas tolerated lower thresholds better than high-grade gliomas (0-2% vs 7-14% permanent deficits at 2-3 mA, p < 0.01). Importantly, 78% of permanent deficits resulted from ischemic injury rather than direct tract damage, predominantly confirmed on postoperative diffusion-weighted MRI. Conclusion: Based on moderate-quality evidence (GRADE: ⊕⊕⊕◯), 3 mA represents a clinically important decision threshold for the general glioma population, supported by the largest evidence base. However, 4-5 mA is an equally valid and preferred stopping threshold for high-grade gliomas and patients with preoperative deficits (2.1% permanent deficit rate). Continuation below 3 mA should be reserved for carefully selected low-grade glioma patients with intact preoperative function, stable continuous MEP monitoring, and tractography guidance. Thresholds below 2 mA carry markedly elevated risk (17.8%) based on limited single-study evidence and should generally prompt cessation. Stimulation thresholds are protocol-dependent and should not be compared across institutions using different pulse widths or frequencies. Vascular preservation is paramount given that most permanent deficits arise from ischemia. (Copyright © 2026 Elsevier Ltd. All rights reserved.) |
| Competing Interests: | Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. |
| Contributed Indexing: | Keywords: Charge density; Corticospinal tract; Glioma surgery; Intraoperative neurophysiological monitoring; Motor evoked potentials; Motor threshold; Stimulation parameters; Subcortical stimulation |
| Entry Date(s): | Date Created: 20260515 Date Completed: 20260612 Latest Revision: 20260616 |
| Update Code: | 20260617 |
| DOI: | 10.1016/j.jocn.2026.112083 |
| PMID: | 42140116 |
| Βάση Δεδομένων: | MEDLINE |
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| Items | – Name: Title Label: Title Group: Ti Data: Evidence-based safe stimulation thresholds in subcortical mapping during glioma surgery: a systematic review and meta-analysis. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AU" term="%22Alsaleh+OI%22">Alsaleh OI</searchLink>; Department of Neurosurgery, Schön Klinik Rendsburg, Rendsburg, Germany. Electronic address: dr.osamaalsaleh@gmail.com.<br /><searchLink fieldCode="AU" term="%22Al+Habal+SN%22">Al Habal SN</searchLink>; Independent Researcher, Rendsburg, Germany.<br /><searchLink fieldCode="AU" term="%22Alomari+AML%22">Alomari AML</searchLink>; Department of Neurosurgery, Johannes Wesling Klinikum Minden, Minden, Germany. – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%229433352%22">Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia</searchLink> [J Clin Neurosci] 2026 Sep; Vol. 151, pp. 112083. <i>Date of Electronic Publication: </i>2026 May 15. – Name: TypePub Label: Publication Type Group: TypPub Data: Journal Article; Systematic Review; Meta-Analysis; Review – Name: Language Label: Language Group: Lang Data: English – Name: TitleSource Label: Journal Info Group: Src Data: <i>Publisher: </i><searchLink fieldCode="PB" term="%22Churchill+Livingstone%22">Churchill Livingstone </searchLink><i>Country of Publication: </i>Scotland <i>NLM ID: </i>9433352 <i>Publication Model: </i>Print-Electronic <i>Cited Medium: </i>Internet <i>ISSN: </i>1532-2653 (Electronic) <i>Linking ISSN: </i><searchLink fieldCode="IS" term="%2209675868%22">09675868 </searchLink><i>NLM ISO Abbreviation: </i>J Clin Neurosci <i>Subsets: </i>MEDLINE – Name: PublisherInfo Label: Imprint Name(s) Group: PubInfo Data: <i>Publication</i>: <2000->: Edinburgh : Churchill Livingstone<br /><i>Original Publication</i>: Melbourne, Vic., Australia : Churchill Livingstone, c1994- – Name: SubjectMESH Label: MeSH Terms Group: Su Data: <searchLink fieldCode="MM" term="%22Glioma%22">Glioma*</searchLink>/<searchLink fieldCode="MM" term="%22Glioma+surgery%22">surgery</searchLink> <br /><searchLink fieldCode="MM" term="%22Brain+Neoplasms%22">Brain Neoplasms*</searchLink>/<searchLink fieldCode="MM" term="%22Brain+Neoplasms+surgery%22">surgery</searchLink> <br /><searchLink fieldCode="MM" term="%22Electric+Stimulation%22">Electric Stimulation*</searchLink>/<searchLink fieldCode="MM" term="%22Electric+Stimulation+methods%22">methods</searchLink> <br /><searchLink fieldCode="MM" term="%22Brain+Mapping%22">Brain Mapping*</searchLink>/<searchLink fieldCode="MM" term="%22Brain+Mapping+methods%22">methods</searchLink> <br /><searchLink fieldCode="MM" term="%22Intraoperative+Neurophysiological+Monitoring%22">Intraoperative Neurophysiological Monitoring*</searchLink>/<searchLink fieldCode="MM" term="%22Intraoperative+Neurophysiological+Monitoring+methods%22">methods</searchLink> <br /><searchLink fieldCode="MM" term="%22Neurosurgical+Procedures%22">Neurosurgical Procedures*</searchLink>/<searchLink fieldCode="MM" term="%22Neurosurgical+Procedures+methods%22">methods</searchLink><br /><searchLink fieldCode="MH" term="%22Evoked+Potentials%2C+Motor%22">Evoked Potentials, Motor</searchLink>/<searchLink fieldCode="MH" term="%22Evoked+Potentials%2C+Motor+physiology%22">physiology</searchLink> ; <searchLink fieldCode="MH" term="%22Evidence-Based+Medicine%22">Evidence-Based Medicine</searchLink>/<searchLink fieldCode="MH" term="%22Evidence-Based+Medicine+methods%22">methods</searchLink> ; <searchLink fieldCode="MH" term="%22Humans%22">Humans</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Objective: Intraoperative subcortical electrical stimulation is essential for safe glioma resection near motor pathways, yet minimum safe current thresholds remain controversial, with published recommendations ranging from 1 to 7 mA. This systematic review synthesizes evidence on safe stimulation thresholds in monopolar subcortical mapping during glioma surgery to provide evidence-based recommendations.<br />Methods: Following PRISMA 2020 guidelines, we systematically searched PubMed, Scopus, Web of Science, and Cochrane Library through November 2025 for studies reporting specific threshold values and motor outcomes in glioma surgery with monopolar subcortical monitoring. Study quality was assessed using the Newcastle-Ottawa Scale. Evidence was synthesized narratively and graded using GRADE methodology. Statistical pooling of proportions used random-effects models with Freeman-Tukey double arcsine transformation.<br />Results: Sixteen studies comprising 1,146 patients were included. Safe threshold recommendations ranged from 1 to 7 mA, with 3 mA applied across the largest patient cohort (seven studies, 728 patients, 63.5%). A clear dose-response relationship emerged: pooled permanent motor deficits increased from 2.1% (95% CI 1.3-3.2%) at thresholds ≥5 mA to 17.8% (95% CI 12.4-24.5%) at thresholds &lt;2 mA. Motor evoked potential (MEP) monitoring significantly reduced permanent deficits from 8.7% to 4.0% (pooled OR 0.43, 95% CI 0.26-0.72, p &lt; 0.001). The threshold-distance relationship approximated 1 mA per 1 mm from the corticospinal tract (r = 0.87, p &lt; 0.001). Low-grade gliomas tolerated lower thresholds better than high-grade gliomas (0-2% vs 7-14% permanent deficits at 2-3 mA, p &lt; 0.01). Importantly, 78% of permanent deficits resulted from ischemic injury rather than direct tract damage, predominantly confirmed on postoperative diffusion-weighted MRI.<br />Conclusion: Based on moderate-quality evidence (GRADE: ⊕⊕⊕◯), 3 mA represents a clinically important decision threshold for the general glioma population, supported by the largest evidence base. However, 4-5 mA is an equally valid and preferred stopping threshold for high-grade gliomas and patients with preoperative deficits (2.1% permanent deficit rate). Continuation below 3 mA should be reserved for carefully selected low-grade glioma patients with intact preoperative function, stable continuous MEP monitoring, and tractography guidance. Thresholds below 2 mA carry markedly elevated risk (17.8%) based on limited single-study evidence and should generally prompt cessation. Stimulation thresholds are protocol-dependent and should not be compared across institutions using different pulse widths or frequencies. Vascular preservation is paramount given that most permanent deficits arise from ischemia.<br /> (Copyright © 2026 Elsevier Ltd. All rights reserved.) – Name: Abstract Label: Competing Interests Group: Ab Data: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. – Name: SubjectMinor Label: Contributed Indexing Group: Data: <i>Keywords: </i>Charge density; Corticospinal tract; Glioma surgery; Intraoperative neurophysiological monitoring; Motor evoked potentials; Motor threshold; Stimulation parameters; Subcortical stimulation – Name: DateEntry Label: Entry Date(s) Group: Date Data: <i>Date Created: </i>20260515 <i>Date Completed: </i>20260612 <i>Latest Revision: </i>20260616 – Name: DateUpdate Label: Update Code Group: Date Data: 20260617 – Name: DOI Label: DOI Group: ID Data: 10.1016/j.jocn.2026.112083 – Name: AN Label: PMID Group: ID Data: 42140116 |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1016/j.jocn.2026.112083 Languages: – Code: eng Text: English PhysicalDescription: Pagination: StartPage: 112083 Subjects: – SubjectFull: Evoked Potentials, Motor physiology Type: general – SubjectFull: Evidence-Based Medicine methods Type: general – SubjectFull: Humans Type: general – SubjectFull: Glioma surgery Type: general – SubjectFull: Brain Neoplasms surgery Type: general – SubjectFull: Electric Stimulation methods Type: general – SubjectFull: Brain Mapping methods Type: general – SubjectFull: Intraoperative Neurophysiological Monitoring methods Type: general – SubjectFull: Neurosurgical Procedures methods Type: general Titles: – TitleFull: Evidence-based safe stimulation thresholds in subcortical mapping during glioma surgery: a systematic review and meta-analysis. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Alsaleh OI – PersonEntity: Name: NameFull: Al Habal SN – PersonEntity: Name: NameFull: Alomari AML IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 09 Text: 2026 Sep Type: published Y: 2026 Identifiers: – Type: issn-electronic Value: 1532-2653 Numbering: – Type: volume Value: 151 Titles: – TitleFull: Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia Type: main |
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