Prevelance Of Atlantoaxial Instability In Individuals With Down Syndrome

Atlantoaxial instability denotes increased mobility at the articulation of the first and the second cervical vertebrae ’’atlantoaxial joint’’.Instability of the atlantoaxial joint in Down syndrome has a variety of predisposing causes.Laxity of the transverse ligament is only one of the several causes of atlantoaxial instability. Hypoplasia, malformation and complete absence of the odontoid process are other anomalies that predispose the cervical spine to instability.In the mildest form,atlantoaxial instability is asymptomatic and is diagnosed during radiography.Symptomatic atlantoaxial instability results from subluxation that is severe enough to injure the spinal cord or from dislocation at the atlantoaxial joint.The aim of our work was to detect the prevalence of AAI in individuals with Down syndrome to avoid complications during activities.The study included 30 patients with Down syndrome 23 male and 7 females who were attending to the pediatric Department of Zagazig University Hospital,Intellectual Education Schools and Rehabilitation Centers.Control group consisted of 20 healthy children of matched age and sex taken from relatives of the cases.Twenty one cases (70%) had no atlantoaxial instability ,four cases had borderline AAI(13.33%) ,three cases(10%) had positive AAI:2 cases were asymptomatic(6.67%) and one case was symptomatic(3.33 %),2 cases were excluded(6.67%) ,were irritable and moved during radiography.We had no cases with neural tube width less than 14mm which is the cut-off point for atlantoaxial instability as mentioned by Brockmeyer (1999).