Summary of findings 3. Neuronavigation image‐guided surgery compared to standard surgery for high‐grade glioma.

Neuronavigation image‐guided surgery compared to standard surgery for high‐grade glioma
Patient or population: high‐grade glioma Settings: specialist centres Intervention: neuronavigation image‐guided surgery (based on post‐operative MRI) Comparison: standard surgery
Outcomes	Illustrative comparative risk* (95% CI)		Relative effect (95% CI)	No. of participants (studies)	Quality of the evidence (GRADE)	Comments
	Assumed risk	Corresponding risk
	Control	Image‐guided surgery
Extent of resection: complete resection	Not estimable	Not estimable	Not reported	45 participants (1 study)	⊕⊝⊝⊝1,2,4 verylow	Small study of highly selected participants at very high risk of allocation bias.Complete resection was achieved in three participants in the control group and five participants in the neuronavigation group. However, there was significant attrition, with not all participants completing imaging, and the denominators for these figures were not stated, precluding formal analysis
Adverse events	Inadequately and inconsistently reported in the trial				⊕⊝⊝⊝2 verylow	Adverse events were reported in an inconsistent manner and not according to the manner prespecified in our protocol. Additionally, we were mainly interested in identifying serious adverse events, which were inadequately reported
Overall survival	Not estimable				⊕⊝⊝⊝3 verylow	Not reported by trial authors so graded as very low quality evidence
Progression‐free survival	Not estimable				⊕⊝⊝⊝2 verylow	Progression‐free survival or time to progression was not reported in the trial
Quality of life	Inadequately reported or not assessed at all in the included trials				⊕⊝⊝⊝3 verylow	Quality of life was reported in the trial but only 19 participants (8 in the neuronavigation arm and 11 in the standard surgery arm) completed questionnaires postoperatively at 3 months', constituting only 64.5% of all eligible participants, and no statistical analysis was presented
*The basis for the assumed risk is only based on individual trials as only single trial reports were available. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval
GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate.

¹Small trial so quality of the evidence downgraded by one level.
²Highly selected participants with potential bias in allocation and performance as well as in other 'Risk of bias' domains, thus downgraded by two levels.
³Outcome was not reported (or inadequately reported for meaningful conclusions to be drawn), therefore giving lowest quality of evidence judgement.