Background
Cerebellar mutism (CM) is characterized by a significant loss of speech in children following posterior fossa (PF) surgery. The biological origin of CM remains unclear and is the subject of ongoing debate. Significant recovery from CM is less likely than previously described despite rigorous multidisciplinary neuro-rehabilitational efforts.
Methods
A national multi-centered retrospective review of all children undergoing PF resection in 4 midsized Canadian academic pediatric institutions was undertaken. Patient, tumor, and surgical factors associated with the post-operative development of CM were reviewed. Retrospective identification of PF surgery patients including those developing and those that did not (internal control).
Results
The study identified 258 patients across the 4 centers between 2010–2020 (mean age 6.73 years; 42.2 female). Overall, CM was experienced in 19.5% of patients (N = 50). Amongst children who developed CM histopathology included medulloblastoma (35.7%), pilocytic astrocytoma (32.6%), and ependymoma (17.1%). Intraoperative impression of adherence to the floor of the 4th ventricle was positive in 36.8%. Intraoperative abrupt changes in blood pressure and/or heart rate were identified in 19.4% and 17.8% of cases. The clinical resolution of CM was rated to be complete, significant resolution, slight improvement, no improvement, and deterioration in 56.0%, 8.0%, 20.0%, 14.0%, 2.0%, respectively. In the cohort of children who experienced post-operative CM as compared to their no-CM counterpart, proportionally more tumors were felt to be adherent to the floor of the 4th ventricle (56.0% vs 49.5%), intraoperative extent of resection was a GTR (74% vs 68.8%), and changes in heart rate were noted (≥ 20% from baseline) (26.0% vs 15.9%). However, a logistic regression for experiencing CM identified only intraoperative impression of adherence to the floor of the 4th ventricle (OR 2.32, p = 0.011), abrupt changes in intraoperative HR (> 20% from baseline) (OR 2.34, p = 0.028), and medulloblastoma histology (OR 3.77, p = 0.001) to significantly associated with development of post-operative CM.
Conclusion
As a devastating surgical complication, identifying and understanding the biological origin of CM is the first step to complication avoidance. Maximal safe resection irrespective of intraoperative pathology remains the strategy to minimize the devastating post-operative development of CM.