Addressing connectomic constraints in early practice of awake-guided neurosurgery: a four-year prospective case-matched analysis
Abstract
Purpose: Awake functional-guided resection (AFGR) is the gold-standard approach in glioma surgery. The learning curve associated with mastering white matter tracts (WMT) identification using direct electrostimulation (DES) mapping remains poorly characterized. The goal of this study was to compare subcortical DES mapping performance between early-career and expert neurosurgeons. Methods: In this prospective, monocentric, case-matched study, patients undergoing AFGR (2022-2025) were operated on either by an early-career neurosurgeon during the first four years of independent practice (cohortA) or by a senior expert neurosurgeon with extensive experience in awake mapping procedures (cohortB). DES-elicited responses were compared using multivariable multinomial regression, adjusting for histology and anatomical location. WMT identification rates were analyzed using a benchmark-normalized Relative Detection Efficiency (RDE). Results: Overall, 352 AFGR procedures were analyzed, including 101 in cohortA. Histology differed between cohorts, with fewer IDH-mutant grade 2 gliomas (46.5% vs 65.3%) and more glioblastomas (27.7% vs 6.4%) in cohortA. Postoperative tumor volume and functional outcomes were comparable. A total of 1,158 DES responses were recorded. Negative motor responses were more frequent in cohortA (+ 11.3%[95%CI:3.3-18.9], P = 0.006), whereas semantic paraphasia tended to be less frequent (- 15.4%[95%CI: - 32.3-0.6], P = 0.079). Identification of the inferior fronto-occipital fasciculus was reduced in cohortA, particularly in left frontal approaches (RDE:0.53[95%CI:0.31-0.81], P = 0.002), consistent with comparable overall extents of resection (EOR) except in frontal tumors. Conclusion: Benchmarking early-career practice of AFGR against expert practice reveals selective, tract- and functional system-specific differences in DES mapping strategies, with minimal impact on EOR and similar functional outcomes. These findings suggest that AFGR is reliably implementable during early independent practice and support a dynamic connectomic constraint framework to guide training.
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BibTeX
@article{ng2026addressing,
title = {{Addressing connectomic constraints in early practice of awake-guided neurosurgery: a four-year prospective case-matched analysis}},
author = {Sam Ng and Andrea Otamendi-Lopez and Basile Martin and Kevin Chalard and Vivien Szabo and Sylvie Moritz-Gasser and Guillaume Herbet and Hugues Duffau},
journal = {Acta Neurochirurgica},
year = {2026},
month = oct,
doi = {10.1007/s00701-026-06978-1},
url = {https://hal.science/hal-05701423v1},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Addressing connectomic constraints in early practice of awake-guided neurosurgery: a four-year prospective case-matched analysis
AU - Sam Ng
AU - Andrea Otamendi-Lopez
AU - Basile Martin
AU - Kevin Chalard
AU - Vivien Szabo
AU - Sylvie Moritz-Gasser
AU - Guillaume Herbet
AU - Hugues Duffau
PY - 2026
DA - 2026/10/12
JO - Acta Neurochirurgica
DO - 10.1007/s00701-026-06978-1
UR - https://hal.science/hal-05701423v1
AB - Purpose: Awake functional-guided resection (AFGR) is the gold-standard approach in glioma surgery. The learning curve associated with mastering white matter tracts (WMT) identification using direct electrostimulation (DES) mapping remains poorly characterized. The goal of this study was to compare subcortical DES mapping performance between early-career and expert neurosurgeons. Methods: In this prospective, monocentric, case-matched study, patients undergoing AFGR (2022-2025) were operated on either by an early-career neurosurgeon during the first four years of independent practice (cohortA) or by a senior expert neurosurgeon with extensive experience in awake mapping procedures (cohortB). DES-elicited responses were compared using multivariable multinomial regression, adjusting for histology and anatomical location. WMT identification rates were analyzed using a benchmark-normalized Relative Detection Efficiency (RDE). Results: Overall, 352 AFGR procedures were analyzed, including 101 in cohortA. Histology differed between cohorts, with fewer IDH-mutant grade 2 gliomas (46.5% vs 65.3%) and more glioblastomas (27.7% vs 6.4%) in cohortA. Postoperative tumor volume and functional outcomes were comparable. A total of 1,158 DES responses were recorded. Negative motor responses were more frequent in cohortA (+ 11.3%[95%CI:3.3-18.9], P = 0.006), whereas semantic paraphasia tended to be less frequent (- 15.4%[95%CI: - 32.3-0.6], P = 0.079). Identification of the inferior fronto-occipital fasciculus was reduced in cohortA, particularly in left frontal approaches (RDE:0.53[95%CI:0.31-0.81], P = 0.002), consistent with comparable overall extents of resection (EOR) except in frontal tumors. Conclusion: Benchmarking early-career practice of AFGR against expert practice reveals selective, tract- and functional system-specific differences in DES mapping strategies, with minimal impact on EOR and similar functional outcomes. These findings suggest that AFGR is reliably implementable during early independent practice and support a dynamic connectomic constraint framework to guide training.
SN - 0001-6268
SN - 0942-0940
ER -