We endeavored to determine the prevalence of occipitoatlantal hypermobility in individuals with Down syndrome, to establish objective radiographic criteria for this entity, and to correlate this with neurologic abnormality. In a retrospective analysis, upper cervical spine radiographs of 210 patients with Down syndrome were compared with those of 102 normal individuals. Radiographs were evaluated using the Powers ratio. Patients identified with radiographic evidence of posterior occipitoatlantal hypermobility were then examined clinically and compared with a matched group of patients with Down syndrome and normal Powers ratios. Of the patients with Down syndrome, 8.5% had a Powers ratio of < 0.55, which was indicative of posterior occipitoatlantal hypermobility (POAH). Furthermore, 66% of those with an abnormal Powers ratio had positive neurologic findings upon physical exam, a finding that was statistically significant when compared to a matched group of patients with Down syndrome and normal Powers ratio.
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http://dx.doi.org/10.1097/01241398-199405000-00006 | DOI Listing |
J Neurosurg Pediatr
January 2020
6Department of Pediatric Neurosurgery, Primary Children's Hospital, University of Utah, Salt Lake City, Utah.
Objective: Hypermobility of the craniocervical junction (CCJ) in patients with Down syndrome (DS) is common. Whereas atlantoaxial (C1-2) hypermobility is well characterized, occipitoatlantal (Oc-C1) laxity is recognized but poorly defined. A clear understanding of the risks associated with DS-related hypermobility is lacking.
View Article and Find Full Text PDFJ Neurosurg Spine
December 2007
Department of Neurosurgery, The Chiari Institute, Harvey Cushing Institute of Neuroscience, North Shore-Long Island Jewish Health System, Manhasset, New York 11030, USA.
Object: Chiari malformation Type I (CM-I) is generally regarded as a disorder of the paraxial mesoderm. The authors report an association between CM-I and hereditary disorders of connective tissue (HDCT) that can present with lower brainstem symptoms attributable to occipitoatlantoaxial hypermobility and cranial settling.
Methods: The prevalence of HDCT was determined in a prospectively accrued cohort of 2813 patients with CM-I.
J Neurosurg
January 1999
Spinal Biomechanics Research Laboratory, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona 85013-4496, USA.
Object: The authors sought to determine the biomechanics of the occipitoatlantal (occiput [Oc]-C1) and atlantoaxial (C1-2) motion segments after unilateral gradient condylectomy.
Methods: Six human cadaveric specimens (skull with attached upper cervical spine) underwent nondestructive biomechanical testing (physiological loads) during flexion-extension, lateral bending, and axial rotation. Axial translation from tension to compression was also studied across Oc-C2.
Spine (Phila Pa 1976)
June 1996
Department of Orthopaedic Surgery, Hyogo Nojigiku Hospital for Disabled Children, Kobe, Japan.
Study Design: In this study, the authors evaluated upper cervical spine in 75 children and adolescents with Down syndrome on the basis of lateral flexion-extension radiographs.
Objective: To assess occipitoatlantal motion and occipitoaxial motion in children and adolescents with Down syndrome compared with age-matched control subjects.
Summary Of Background Data: Although previous studies have described a high prevalence of occipitoatlantal hypermobility in Down syndrome, there have been no comparisons with age-matched control subjects.
J Pediatr Orthop
July 1994
Section of Orthopaedics, Medical College of Georgia, Augusta 30912-4030.
We endeavored to determine the prevalence of occipitoatlantal hypermobility in individuals with Down syndrome, to establish objective radiographic criteria for this entity, and to correlate this with neurologic abnormality. In a retrospective analysis, upper cervical spine radiographs of 210 patients with Down syndrome were compared with those of 102 normal individuals. Radiographs were evaluated using the Powers ratio.
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