Präoperatives Mapping der Sprachfunktion bei Kindern - eine systematische Übersichtsarbeit

In pediatric brain tumor/epilepsy surgery, preserving eloquent areas is essential beside sufficient resection margins. Electrical stimulation mapping (ESM) and the Wada-procedure are accepted as gold standarts for the assessment of language function. However, both methods are invasive with varying degrees of feasibility. The aim of this review was to summarize preoperative language mapping data in children for identification of hemipsheric language dominance (HD) or localization of language-eloquent regions, highlighting the feasibility, strengths and limitations of invasive methods and noninvasive alternatives.

A systematic review was conducted using PubMed and registered in PROSPERO. The following keywords were used to identify articles eligible for review: children, brain mapping, children".

38 articles examining invasive (ESM, Wada, electrocorticography (ECOG)) and noninvasive methods (task-based and resting-state fMRI, repetitive navigated TMS (rnTMS), magnetoencephalography and tractography) were included. Most studies (n=23) were feasibility analyses, whereas 16 validation studies were identified. Invasive methods require extensive compliance resulting in success rates of 19% (3/19) for children below 10 years, and seizures in up to 35% (43/122) of patients undergoing ESM. Non-invasive alternatives proved to be safe and could be integrated into clinical routine, with MEG and tb-fMRI mostly utilized for determination of HD and rnTMS and tractography analyzed for identification of language-eloquent areas. For determination of HD, tb-fMRI and MEG displayed concordance rates with invasive mapping from 0.29-0.89. rnTMS and tractography identified eloquent areas with sensitivities between 0.20-0.97. Postoperative outcomes were reported in 13 studies (174/1075 patients) whereby language outcome predicition was aimed only in two cohorts (ECOG and tractography). Resection of ECOG hotspots was not assciated with (worse) postoperative language outcome. In contrast, injury of subcortical language tracts significantly correlated with postoperative language deficit (R=0.7, p<0.001).

The challenges in pediatric neurosurgery are mirrored in the limited literature where postoperative outcomes are rarely reported. However, there are suitable alternatives to invasive methods, each with specific strenghts and weaknesses for determining HD or location analysis of language areas. Prospective, multicenter studies should be initiated to further validate these methods.