Sleep-disordered breathing in patients with Chiari malformation type II: a case-control study and review of the literature

Study Objectives: The main aim was to evaluate the prevalence of sleep-disordered breathing (SDB) in patients with Chiari II malformation (CM-II). The secondary objectives were to evaluate the association between SDB, morphological abnormalities, and neurological symptoms and to review the literature on patients with SDB and CM-II.Methods: The study has a cross-sectional, case-control design. Patients with CM-II (patients) were compared to control patients referred for clinical polysomnography in the Sleep Medicine Unit, matched for age and sex. All patients underwent brain and spinal cord magnetic resonance imaging, and polysomnography was conducted for all participants. A review of the literature about SDB in patients with CM-II was performed.Results: Forty patients were included (20 patients vs 20 control patients). SDB was identified in 45% of patients, a significantly higher prevalence compared to control patients. Three patients presented with purely obstructive SDB, 3 patients with purely central SDB, and 3 patients with both obstructive and central SDB. Compared with control patients, patients with CM-II showed a higher oxygen desaturation index (median: CM-II, 3.7; interquartile range, 1.6-19.5; control patients: 1.1; interquartile range, 0.3-3.2) and obstructive apnea-hypopnea index (median: CM-II, 1.5; interquartile range, 0.5-5.1; control patients, 0.1; interquartile range, 0.0-0.7). A logistic regression showed that the risk of developing SDB in patients affected by CM-II was 14.7 times higher than in the control population.Conclusions: Our study and literature review showed a high prevalence of SDB in patients with CM-II. These patients are often asymptomatic at diagnosis, suggesting that PSG should be routinely provided in this population.