Long-Term Outcomes Associated With Posterior Fossa Syndrome in Survivors of Childhood Medulloblastoma.

Importance: Posterior fossa syndrome is a debilitating surgical complication affecting communication, motor skills, mood, language, and working memory in children treated for posterior fossa tumors. Although many recover from acute symptoms, the lifetime impact of posterior fossa syndrome remains unknown. Objective: To evaluate the long-term neurological, neurocognitive, social, and quality of life outcomes associated with posterior fossa syndrome among survivors of medulloblastoma. Design, Setting, and Participants: This retrospective cohort study included survivors of childhood medulloblastoma diagnosed between 1985 and 2012, with more than 5 years from diagnosis. All participants were treated at a tertiary academic center. Data were analyzed from January 1, 2024, to December 1, 2025. Exposure: History of posterior fossa syndrome. Main Outcomes and Measures: Outcomes of interest included neurocognitive functioning (attention, cognitive flexibility, and visuomotor speed), neurological outcomes (cerebellar dysfunction, cranial nerve disorders, dysarthria, headaches, movement disorders, paralytic disorders, peripheral motor or sensory neuropathy, and seizures), physical performance, and social functioning. Statistical analysis included Mann-Whitney U, χ2, or Fisher exact tests, with multivariable linear regression used to assess the associations of posterior fossa syndrome with outcomes while adjusting for confounders. Results: A total of 158 participants (median [range] age at assessment, 25 [11-44] years; 96 [60.8%] male) were assessed, including 37 (23%) who developed posterior fossa syndrome and 121 controls who did not, with no differences in age at diagnosis, radiation dose, or age at assessment a median (range) follow-up of 14.2 (7.8-33.1) years. In adjusted models, participants with posterior fossa syndrome performed worse than those without in focused attention (β = -1.04 [95% CI, -1.62 to -0.45]; P < .001), motor-processing speed (β = -0.62 [95% CI, -1.16 to -0.09]; P = .02), cognitive flexibility (β = -0.85 [95% CI, -1.44 to -0.27]; P = .005), visuomotor processing speed (β = -0.65 [95% CI, -0.97 to -0.33]; P < .001), and physical performance test scores (β = -3.65 [95% CI, -5.36 to -1.93]; P < .001). Participants with posterior fossa syndrome were also more likely to require assistance with routine daily needs (odds ratio, 8.00 [95% CI, 2.56 to 25.04]; P < .001). Conclusions and Relevance: In this long-term cohort study of survivors of medulloblastoma, individuals with history of posterior fossa syndrome exhibited persistent neurocognitive and physical deficits compared with those without history of posterior fossa syndrome. Despite resolution of acute postoperative symptoms, posterior fossa syndrome was associated with lasting impairment, underscoring the need for improved surgical approaches, continued surveillance, and tailored interventions to optimize functional outcomes.