Background: Although patients with myelomeningocele and the Chiari II
malformation are known to have sleep apnea and respiratory control def
icits, the prevalence, types, severities, and associations of sleep-di
sordered breathing (SDB) have not been adequately defined. Methods: A
cross-sectional study of our myelomeningocele clinic population was un
dertaken to correlate polysomnographic results with historical data an
d findings from magnetic resonance imaging of the Chiari malformation,
pulmonary function results, and nocturnal pulse oximetry. Results: A
questionnaire survey of symptoms was available for 107 of 109 children
(98% of the clinic population), and 85 patients agreed to undergo ove
rnight polysomnography. Breathing during sleep was classified as norma
l in 31 cases (37%), mildly abnormal in 35 cases (42%), and moderately
/severely abnormal in 17 cases (20%). Among the 17 patients with moder
ately/severely abnormal SDB, 12 patients had predominantly central apn
eas and 5 had predominantly obstructive apnea. Patients with a thoraci
c or thoracolumbar myelomeningocele, those who had previously had a po
sterior fossa decompression operation, those with more severe brain-st
em malformations, and those with pulmonary function abnormalities were
more likely, to have moderately/severely abnormal SDB, relative risks
(95% confidence intervals) 9.2 (2.9 to 29.3), 3.5 (1.3 to 8.9), 3.0 (
0.9 to 10.5), and 11.6 (1.6 to 81.3), respectively, Failure of obstruc
tive SDB to resolve after adenotonsillectomy in four patients suggeste
d abnormal control of pharyngeal airway patency during sleep. Nocturna
l pulse oximetry accurately predicted moderately/severely abnormal SDB
with a sensitivity of 100% and a specificity of 67%. Conclusions: The
pathogenesis of SDB in patients with myelomeningocele involves the fu
nctional level of the spinal lesions, congenital and acquired brain-st
em abnormalities, pulmonary function abnormalities, disorders of upper
airway maintenance, and sleep state. Polysomnography and nocturnal pu
lse oximetry should be performed in high-risk patients to detect and c
lassify SDB.