ATLANTOAXIAL INSTABILITY IN DOWNS-SYNDROME - A 5-YEAR FOLLOW-UP-STUDY

In 1986 all 90 children aged 4-19 years with Down's syndrome attending school in the area served by the Southern Derbyshire Health Authority underwent radiography to identify atlantoaxial instability (AAI). Thi s study details repeat observations five years later. Full results wer e available on 67 (74%), information on health status was available on the remaining 19 (21%); four (4%) were untraced. There was an overall significant reduction in the atlanto-axial gap over five years. No on e developed AAI on repeat testing who had not had it earlier. One chil d who had previously had normal neck radiography developed acute sympt omatic AAI after ear, nose, and throat surgery. Radiographs were done on three occasions on the same day in 49 individuals, ensuring full fl exion of the upper neck. There were no significant differences between the radiographs, even in five subjects with AAI. Management of AAI in Down's syndrome is discussed in the light of these findings. Radiogra phy can reliably detect children with chronic AAI who may be at risk o f gradually developing symptoms; this may justify a screening programm e. This must be distinguished from those who develop symptoms after ac ute trauma or anaesthesia, for which specific precautions are needed, and previous screening radiographs are unhelpful.