Table 3

Non-prognostic features (NPF)

NPF featuresNon-prognostic evidence base
FeaturePopulation(s) or Subgroup(s)CommentsIndividual
Individual studies*Meta-analytical
Publication years
(first, last)
GRADE score
Clinical features
Sex: male vs femaleAdults and children with FLE, TLE, ET, tuberous sclerosis, MRI neg TLE, repeat surgery, hemispherectomies, low grade gliomasAll were non-significant, a large proportion even on weighted univariate tests, which otherwise tend to overestimate significance.
Individual unweighted effect sizes ranged from OR 0.83 (0.42, 1.64)c in repeat surgery for focal DRE14 to OR 1.44 (0.86, 2.41) in MRI negative TLE.25
5974148Englot, Wang; Englot, Rolston; Zhang, Hu; Fallah, Guyatt; Ibrahim, Morgan; Wang, Zhang; Krucoff, Chan; Englot, Breshears; Hu, Zhang; Shan, Fan; Cao, Liu2012–2018+++
Epilepsia partialis continua (EPC)Children undergoing hemispherectomiesNot significant on unweighted univariate testing and result is from only one meta-analysis.1277Cao, Liu2016++
Imaging features
Number of cortical tubersTuberous sclerosisNumbers of tubers did not predict outcomes. See online supplemental table 5 for observations on methodology, sample sizes, adjustments and heterogeneity.28624Zhang, Hu; Fallah, Guyatt; Ibrahim, Morgan2013–2015++
Magnetic 1H spectroscopyTLE adults and childrenProbably no more valuable than conventional MRI abnormality (online supplemental table 5).12122Willmann, Wennberg2006+
Very low
EncephalomalaciaAdults and childrenEncephalomalacia was NS in the Cochrane meta-analysis, it was also not significant on subgroup analyses.22 3175West, Nevitt2019+
Very Low
Enhancement, oedema, and/or mass effectLow grade gliomas in adultsThese combined features are not clinically prognostic of low-grade glioma resection for seizure freedom. Although NS, the point estimate and CI are unavailable.264123Shan, Fan2018+
Very low
Vascular lesionsAdults and children with TL and ETOnly one meta-analysis investigated this in 2004, comprising only three individual studies, its pathological counterpart was also NS.22 <<35113Tonini, Beghi2004+
Very low
Neurophysiological features
Intraoperative invasive EEGChildren and adults with FLEElectrico-corticography did not effect outcomes102421Englot, Wang2012+++
Video telemetry and long-term monitoringChildren and adults with FLE, lesional and non-lesional TLE and ETLesional TLE cases do well, and this was the only subgroup in which long-term monitoring had a point effect size estimate greater than 1.173865Englot, Wang; Kobulashvili, Kuchukhidze2012, 2018+
Very low
Surgical technique or anatomic features
Mesial vs lateral TL focusMRI neg TLEMesial or lateral TLE, as determined by sEEG, subdural grids, or ATL/SAH vs neocortectomy, are not significant.928Wang, Zhang2016+
Very low
Side of resection (left vs right)Children and adults,
Non-lesional, TLE, FLE, ET, MRI negative TLE, repeat surgery, hemispherectomies
This feature is unlikely to be prognostic—see online supplemental table 5.6550188Tonini, Beghi; West, Nevitt; Willmann, Wennberg; Ansari, Tubbs; Englot, Wang Englot; Rolston; Wang, Zhang; Krucoff, Chan; Englot, Breshears; Hu, Zhang; Ansari, Maher2004–2019+++
Frontal, central, or posterior resections vs otherET, adults, non-lesionalNot prognostic81?Ansari, Tubbs2010+
Very low
Geographical location of surgeryTuberous sclerosis in childrenOnly one meta-analysis investigated North America vs Elsewhere, and the GRADE score is from this meta-analysis alone.18620Ibrahim, Morgan2015+++
Pathological features
Neuro-migrational defectsTL and ET
children and adults
There was a trend whereby neuromigrational deficits were negative prognostic factors, but the number of participants in this analysis was unclear.?6Tonini, Beghi2004+
Very Low
Astrocytoma vs non-astrocytomaLow grade gliomas in adultsThe exact numbers of patients were not provided for this particular analysis.<2641<23Shan, Fan2018+
Very Low
  • See online supplemental table 5 for more details and online supplemental materials for full list of references.

  • *Upper bound of estimate, not including subgroup analyses.

  • m, multivariate; u, univariate; c, calculated (usually unweighted) effect size; ET, extratemporal; FLE, frontal lobe epilepsy; MCD, malformations of cortical development; NS, not significant; PLS, projection to latent space; TL, temporal lobe.