title: Is there a correlation between sleep disordered breathing and foramen magnum stenosis in children with achondroplasia?
abstract: Children with achondroplasia have midface hypoplasia, frontal bossing, spinal stenosis, rhizomelia, and a small foramen magnum. Central sleep apnea, with potential resultant sudden death, is thought to be related to compression of the spinal cord at the cervicomedullary junction in these patients. Screening polysomnography and/or cervical spine MRI are often performed for infants with achondroplasia. Decompressive suboccipital craniectomy has been performed in selected cases. We aim to better delineate the relationship between polysomnography, cervical spine MRI, and indications for surgical decompression in achondroplasia.We retrospectively review electronic medical records of all children with achondroplasia in our IRB-approved skeletal dysplasia registry who had received screening polysomnography and cervical spine MRI examination was performed. We explored correlations of polysomnography, MRI parameters, and need for decompressive surgery. Seventeen patients with both polysomnography and MRI of the cervical spine met inclusion criteria. The average age at time of the sleep study was 2.4 ± 3.6 years. An abnormal apnea-hypopnea index was found in all patients, with central sleep apnea found in 6/17. Five patients (29%) required foramen magnum decompression. We found no statistically significant correlation between central sleep apnea and abnormal MRI findings suggestive of foramen magnum stenosis. Screening polysomnography is an important tool but does not appear to correlate with MRI findings of foramen magnum stenosis. Cord compression, with either associated T2 cord signal abnormality or clinical findings of clonus, was most predictive of subsequent surgical decompression.
authors.affiliation: Department of Orthopedics and Sports Medicine, Seattle Children's Hospital, University of Washington, Seattle, Washington.
authors.forename: Klane K
authors.initials: KK
authors.lastname: White
authors.affiliation: Department of Radiology, Seattle Children's Hospital, University of Washington, Seattle, Washington.
authors.forename: Shawn E
authors.initials: SE
authors.lastname: Parnell
authors.affiliation: Department of Pediatrics, Division of Pulmonary and Sleep Medicine, Seattle Children's Hospital, University of Washington, Seattle, Washington.
authors.forename: Yemiserach
authors.initials: Y
authors.lastname: Kifle
authors.affiliation: Department of Pediatrics, Division of Pulmonary and Sleep Medicine, Seattle Children's Hospital, University of Washington, Seattle, Washington.
authors.forename: Marcella
authors.initials: M
authors.lastname: Blackledge
authors.affiliation: Department of Orthopedics and Sports Medicine, Seattle Children's Hospital, University of Washington, Seattle, Washington.
authors.forename: Viviana
authors.initials: V
authors.lastname: Bompadre
mesh_terms: D000130:Achondroplasia / Q000150:complications / Q000503:physiopathology*; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003251:Constriction, Pathologic; D005260:Female; D005539:Foramen Magnum / Q000503:physiopathology*; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D017286:Polysomnography; D011379:Prognosis; D012189:Retrospective Studies; D012891:Sleep Apnea Syndromes / Q000209:etiology / Q000503:physiopathology*
keywords: achondroplasia; foramen magnum stenosis; magnetic resonance imaging; sleep disorders