ID #956 Investigating distinct patterns of surgical damage associated with Posterior Fossa Syndrome/Cerebellar Mutism Syndrome using multivariate lesion symptom mapping
Mina Langhein, Sarah Elsayed, Peter Selhausen, Lisa Bußenius, Julia Forisch, Jan Feldheim, Matthias Wagner, Marthe Sönksen, Christian Fiedler, Denise Obrecht-Sturm, Brigitte Bison, Michael Bockmayr, Robert Schulz, Stefan Rutkowski, Martin Mynarek, Lasse DührsenAbstract
Background
Posterior Fossa Syndrome/Cerebellar Mutism Syndrome (PFS/CMS) is a serious surgical complication that causes severely debilitating long-term deficits in communication, motor function and cognition in affected children. Despite emerging evidence that injury to efferent cerebellar pathways may account for the wide variety of symptoms observed in PFS/CMS, the underlying pathophysiology remains poorly understood. Here, we aim to identify critical structures that are frequently affected in PFS/CMS using multivariate lesion symptom mapping.
Methods
Early postoperative cerebellar lesions were analyzed in 154 children with midline intraventricular medulloblastoma from a German medulloblastoma series. 52 children developed postoperative PFS/CMS (34%) defined as complete mutism (PFS1, 41/52) or the inability to string 3-word sentences (PFS2, 11/52). Lesions were manually segmented and defined as new T2-FLAIR hyperintensities surrounding the surgical cavity, reflecting surgery-related tissue damage. Lesion maps were transformed into MNI-152 space using a customized pipeline. Sparse canonical correlation analysis for neuroimaging (SCCAN) was conducted to identify patterns of surgical damage associated with PFS/CMS. 47/154 patients underwent follow-up neuropsychological testing. The surgical approach to tumor resection was evaluated from surgical reports.
Results
SCCAN identified a pattern of surgical damage significantly associated with PFS/CMS (r=.35, p<.001) with peak voxel weights in the right superior cerebellar peduncle, vermal lobule VI and left lobule IX. PFS/CMS was associated with reduced processing speed (β = −.42, p=.006) and fine motor skills (Purdue Pegboard dominant hand: β = −.42, p=.011; non-dominant hand: β = −.48, p=.004). Vermian incision was not associated with an increased risk for PFS/CMS (OR = 1.78, p=.204).
Conclusion
Our findings suggest that surgical damage to the cerebellar outflow pathways and superior vermis is associated with PFS/CMS, potentially implicating disrupted cerebello-cortical communication. Surgical techniques that minimize damage to these structures may reduce the incidence and severity of PFS/CMS in the future.