Atlantoaxial instability (AAI) is characterized by hypermobility of C1-C2 joint due to laxity of alar ligament, being common in Down syndrome patients. The aim of this study is to verify AAI incidence and its association with generalized ligamentous laxity in Down syndrome. Eighty children were selected, 34 (42.5%) males and 46 (57.5%) females, aged from 5.6 to 15 years-old (average = 9). Patients were evaluated by questionaire and an X-ray imaging of cervical spine in a flexed lateral view. Clinical features amount to 58%, most expressed as weakness of lower limbs. 77,5% of atlanto-odontoid spaces were as small as 4.5mm; 15% were between 4.5 to 6mm; and 7.5% were greater than 6mm. Patients presenting generalized ligamentous laxity (group 1) did not show a greater incidence of AAI compared to those not presenting that condition (group 2). The authors concluded that AAI is a common disorder in Down syndrome, having no direct association to generalized ligamentous laxity.
Down syndrome; Pathology; Cervical spine
