Research in context
Evidence before this study
We searched PubMed for all reports in English with available abstracts published until Jan 1, 2021, using the search terms “cerebellar mutism”, “posterior fossa syndrome”, “telovelar”, “transvermian”, and revealed 297 references of interest. All abstracts were read for content of surgical approach and cerebellar mutism, cerebellar mutism syndrome, or posterior fossa syndrome. No further inclusion or exclusion criteria were used. Postoperative speech impairment (POSI) is described as a complication of surgical removal of mainly midline tumours in the posterior fossa in children (aged <18 years). POSI occurs within days of surgery and improves within months, but the terminology for speech impairment differs between studies. Route of surgical access to the tumour is thought to influence this functional outcome; however, previous studies had few patients or a retrospective design, and their conclusions are divergent.
Added value of this study
This study presents new prospectively collected data about speech impairment after posterior fossa tumour resection in children, using different surgical approaches. Our study suggests a new framework for categorising POSI and provides prognostic models to estimate the time to improvement. The data did not suggest a difference in risk of POSI between telovelar or transvermian surgical approaches. Mutually adjusted analyses indicated that the risk of developing POSI was higher in younger children, in children with tumours in the fourth ventricle and brainstem, and in children with medulloblastoma and atypical teratoid rhabdoid tumour.
Implications of all the available evidence
Our study does not implicate a preference for surgical approach in posterior fossa tumour management in children. Our findings suggest that the biology and location of the tumour influence the risk of POSI. Risk stratification for POSI by age and tumour location should be applied when informing patients and parents before surgery, and the prognostic models on recovery of speech will provide new information for patients with POSI and their families.