The radiographs and clinical evaluations of 90 children with Down’s syndrome were reassessed after an interval of 5 years in a study of atlantoaxial instability (AAI) at the Derbyshire Children’s Hospital and Infirmary, Derby, UK. Only one child had symptoms of AAI over 5 years. A 9 year old developed acute torticollis after ENT surgery; radiographs showed a rotatary dislocation and a AA gap of 7 mm (>4 mm is abnormal). Of 7 with AAI at initial exam in 1986, 5 were abnormal in 1991, but none had symptoms. No additional cases of AAI were found at 5 years. In fact, a significant reduction of the mean AA gap from 2.95 mm to 2.45 mm occurred over 5 years. (A 1 mm difference in AA gap can occur between 2 of 3 radiographs taken 10 minutes apart). Radiographs were taken with maximal flexion of the upper neck. 
COMMENT. Chapman S, of the Radiology Department, Children’s Hospital, Birmingham, cautions that 1) the use of a single flexion view is diagnostic of subluxation - not AA instability: 2) the apparent lessening of the gap with age may be difficult to distinguish from observed variations in repeat measurements; 3) the spine radiograph is not a good clinical predictor in Down’s syndrome and, in the presence of symptoms or neurological signs, should probably be replaced by MRI or CT; and 4) films in flexion and extension should be obtained before anesthesia or before engaging in high risk sports. 
To avoid possible exacerbation of AAI and symptoms following recurrent trauma and hyperflexion of the neck, the authors restricted sports activities of the seven children who initially were found to have AAI on radiographic examination. Diving, trampolining, gymnastics, judo, and rugby were forbidden, and running, jumping, and swimming were encouraged. None developed symptoms. However, other reports suggest that restriction of activities is unnecessary, and radiographs prior to sporting activities are unjustified. The clinical examination and history of symptoms appear to be more important than radiographic screening tests. The management of this complication of Down’s syndrome remains controversial. Parents should be made aware of potential cervical spine problems in a child with Down’s syndrome.
NON-TRAUMATIC ATLANTO-AXIAL SUBLUXATION is reported from Mater Private Hospital, Dublin, Ireland, in an 8-year-old child with a previous history of neonatal retropharyngeal abscess . Limitation of neck movement was followed by cord compression and progressive quadriparesis in a period of 6 months. Function improved after anterior decompression and occipito-cervical fusion.