NCOG-11. FACTORS PREDICTING SPEECH AND GAIT RECOVERY IN CHILDREN WITH POST-OPERATIVE POSTERIOR FOSSA SYNDROME (PFS)

Abstract Posterior fossa syndrome/cerebellar mutism syndrome is a surgical complication of posterior fossa tumor resection, especially midline tumors. Initially thought to involve complete mutism, PFS is now recognized as a complex syndrome involving loss of language (complete [PFS1] and incomplete [PFS2]). Additional symptoms include apraxia, movement disorder, motor and coordination deficits, and emotional lability. The aim of this study was to identify factors that influence delayed speech and independent gait recovery in children with PFS. We prospectively studied 73 children ≥3 years of age with medulloblastoma who developed PFS (SJMB12, NCT01878617). Enrolled children received standardized neurologic examinations and serial imaging before, during and up to five years after completion of therapy. Neurological examinations included scale for assessment and rating of ataxia (SARA), CTCAE grading of neurologic deficits, and severity of injury to the superior cerebellar peduncles (SCP) on post-operative MRI. Median time to speech recovery was 1.4 months (range 0.3-14.3); 81% had return of speech at 3 months and 97% at 12 months. On multivariable Cox regression analysis, complete mutism (HR 0.17, p<0.0001) and inability to sit (HR 0.40, p=0.001) were associated with delayed speech return. Independent ambulation was regained by 80.8% at a median of 2.3 (range 0.3-71.3) months. 70% had a return of ambulation at 12 months and 77% at 24 months. On multivariable Cox regression analysis, complete mutism (HR 0.32, p=0.016), inability to sit (HR 0.30, p=0.002), SARA score (HR 0.94, p=0.002), and right SCP injury (HR 0.47, p=0.014) were significantly associated with delayed return of ambulation. Presence of mutism, inability to sit unassisted, higher SARA score, and right SCP injury at the time of PFS diagnosis are associated with time to recovery of speech/language and ambulation. Our findings have prognostic implications for families and to help identify children in need of more intensive interventions.