Abstract
BACKGROUND
Cerebellar mutism syndrome (CMS) complicates posterior fossa surgery in up to 30% of cases leading to prolonged rehabilitation and most often incomplete recovery and life long disability. This project seeks to develop and validate predictive scoring system based upon imaging characteristics from pre-operative scans to inform the surgical consent procedure.
METHODS
International workshop involving neuroradiologists, neurosurgeons and neuro-oncologists from 11 European and North American centres. During the workshop, experts reviewed pre-operative scans blinded to mutism status. Imaging data were recoded in to binary variables to test a previous preliminary risk assessment tool which based on data from two UK centres.
RESULTS
The cohort consists of 245 posterior fossa tumour cases (mean age 8.23 ± 4.45 years) of whom 40 developed post-operative CMS (latency 0-8 days, duration 1 day-3 months). Inter-rater agreement of imaging predictors ranged from moderate (primary location k=0.6, dentate nucleus invasion k=0.41) to fair (cerebellar hemisphere invasion k=0.38, middle cerebellar peduncle invasion and/or compression k=0.20). The preliminary model demonstrated the ability to identify low risk patients (CMS rate 1%, 1/83). Further mathematical modelling to identify patients with higher risks is in process based upon prediction accuracy, inter-rater reliability of predictors and usefulness in clinical setting.
CONCLUSIONS
This is the largest multi-centre cohort to be studied in this way. We identified low risk cases from all participating centres, accounting for 83/245 (34%) cases. We propose extending access to this scoring system to additional centres via a web based module offering training and scoring validation for each centre.