Posterior fossa decompression in patients with Chiari malformation type 1: effect on sleep apnea and follow-up outcomes.

Purpose: Sleep apnea, posing significant health risks, is frequently associated with Chiari malformation (CM), characterized by cerebellar tonsil herniation through the foramen magnum. Central sleep apnea (CSA) in CM results from impaired brain-to-muscle signaling and requires treatment. Conversely, obstructive sleep apnea (OSA), arising from throat muscle relaxation, typically unrelated to CM, often coexists. This study evaluates the effectiveness of posterior fossa decompression (PFD) on sleep apnea.

Methods: A retrospective chart review was conducted of pediatric patients with CM-1 and sleep apnea who underwent PFD between April 1, 2004, and September 30, 2022. Data collected included demographics, clinical characteristics, adenotonsillectomy status, PFD details, and sleep study parameters like the apnea-hypopnea index and respiratory disturbance index. Statistical analysis assessed the surgery's impact on sleep apnea severity.

Results: The study included eleven patients, predominantly male (63.6%). All had OSA (100%), with 63.6% also having CSA. Preoperative sleep studies classified OSA severity as 36.4% mild, 18.2% moderate, and 45.5% severe, with no change post-surgery. CSA severity initially included seven mild cases, which became three mild, one moderate, and three resolved cases post-surgery. Among seven patients who had adenotonsillectomy before decompression, five showed no improvement in OSA severity post-surgery.

Conclusion: This study elucidates the complex relationship between CM-1, sleep apnea, and PFD. The findings show the persistence of sleep apnea in some patients and highlight the need for continuous monitoring of these patients in order to optimize their care after surgery.