[Diagnosis and treatment of congenital atlantoaxial dislocation]

23 patients, aged from 10 to 52 years (24 years on the average), with congenital dislocation of atlanto-axial joint were treated. Symptoms were chiefly functional disturbance of motion; diagnosis was based on malformation of cranio-vertebral junction shown on radiograms; and operation of transoral decompression or/and posterior decompression and fusion was performed on each patient. Such operation did benefited 19 patients, a rate of 82.6%, evaluated in 0.2 to 8.7 years (1.9 years on the average) after operation. Skull traction tried on several patients failed to reduce the dislocation because of dense fibrous tissues in the joint space, hindering reduction. Posterior decompression alone was seldom effective and even dangerous. For this condition, transoral decompression and anterior or posterior fusion is a good choice of treatment. Mechanism of developing symptoms, key points of making diagnosis and surgical procedures were described in detail.