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Journal Club

Tumor/Skull Base

Awake vs. asleep motor mapping for glioma resection: a systematic review and meta-analysis

Acta Neurochirurgica | 2020

Rapid review note

Journal Club is a rapid, AI-assisted appraisal layer. It highlights study design, effect estimates, and practice relevance, but it is still a briefing, not a replacement for the paper.

For education only. Not medical advice.

Paper snapshot

Rapid study overview

Open paper

DOI

10.1007/s00701-020-04357-y

PMID

N/A

PICO

Population

2351 glioma patients from 17 studies undergoing motor-area mapping during resection near the perirolandic cortex or descending motor tracts.

Intervention

Awake craniotomy with intraoperative stimulation mapping.

Comparator

General anesthesia with motor mapping.

Outcomes

Extent of resection and postoperative neurologic morbidity, stratified by timing and severity.

Design

Type

Systematic review and random-effects meta-analysis

Randomized

No

Multicenter

N/A

Blinded

N/A

Follow-up

Study-level follow-up varied across included series

Primary endpoint

Extent of resection and postoperative neurologic morbidity after motor mapping for glioma surgery.

Secondary endpoints

  • Early neurologic deficits
  • Late neurologic deficits
  • Severe versus non-severe morbidity

Practice impact

What this means

This review is useful because it pushes back against oversimplifying awake surgery. For motor mapping specifically, both awake and asleep approaches looked workable, and the pooled data did not prove a clear universal winner. The practical choice should still be driven by tumor anatomy, mapping goals, and team experience.

Bottom line

For motor-area glioma surgery, this review supports that both awake and asleep mapping can be performed safely, and it does not prove a clear universal outcome advantage for either approach.

Strength of evidence

low

Recommendation

do not change

Why it matters

  • The extent-of-resection signal favored awake surgery only as a trend, not a clear statistical win.
  • Neurologic morbidity differences were not convincingly different across groups.
  • Case selection and team expertise probably matter more than a simple awake-versus-asleep rule.

What would change my mind

  • A prospective randomized comparison showing a clear resection or neurologic advantage for one mapping strategy in motor-area gliomas.
  • Consistent modern multicenter data demonstrating that one approach outperforms the other after controlling for tumor location and case selection.

Critical appraisal

How strong is the paper?

Methods critique

Risk of bias

The evidence base was drawn mainly from retrospective surgical series rather than randomized comparisons, so treatment selection and center expertise heavily influence the pooled estimates.

Confounding

Choice of awake versus asleep mapping is often driven by tumor location, language involvement, patient cooperation, and anesthetic preference, which makes direct group comparison vulnerable to case-mix imbalance.

Missing data

Study-level reporting varied, and deficit timing and severity were not uniform across all included series, which weakens the precision of pooled morbidity estimates.

Multiplicity

The review split neurologic deficits by timing and severity and reported several pooled comparisons, increasing the chance of overinterpreting nonprimary subgroup signals.

Notes

  • The meta-analysis included 17 studies and 2351 patients.
  • The pooled extent-of-resection difference only trended toward significance.
  • No neurologic morbidity comparison reached a clear statistically significant difference.

Stats check

NNT

N/A

Effect sizes

  • Mean extent of resection trended higher with awake mapping at 90.1% (95% CI 85.8-93.8) versus 81.7% (95% CI 72.4-89.7), p=0.06.
  • Early neurologic deficits were 20.9% versus 25.4%, p=0.74.
  • Late neurologic deficits were 17.1% versus 3.8%, p=0.06, and severe morbidity was 2.6% versus 4.5%, p=0.89.

Absolute effects

  • The pooled extent-of-resection difference was about 8.4 percentage points in favor of awake mapping.
  • Non-severe morbidity was 28.4% with awake surgery versus 20.1% with general anesthesia.
  • Severe morbidity remained uncommon in both groups at 2.6% versus 4.5%.

Concerns

  • Most pooled comparisons were not statistically significant.
  • The paradoxically higher late deficit estimate with awake surgery likely reflects study heterogeneity and case selection rather than a clean causal effect.
  • This meta-analysis cannot answer questions about language mapping, which often drives the awake decision in practice.

External validity

Who it applies to

Glioma patients with tumors in or near motor pathways where either awake or asleep stimulation mapping is technically feasible.

Who it does not

Cases driven primarily by language mapping requirements or centers that do not routinely perform both awake and asleep mapping safely.

Generalizability notes

  • The review is most useful for motor mapping rather than all awake glioma surgery.
  • Center expertise likely matters more than the pooled average difference.
  • Because both strategies appeared safe, local workflow and tumor specifics remain important.

Evidence trace

Source trace and metadata

Citations (4)

claim_id

methods_critique.risk_of_bias

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p. 1

claim_id

stats_check.effect_sizes

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p. 1

claim_id

stats_check.concerns

locator

p. 2

claim_id

practice_impact.bottom_line

locator

p. 1

Metadata

Generated at

2026-03-08T15:40:00-05:00

Version

manual-pdf-repair-v1