Atlantoaxial instability associated with pan cervical vertebral fusion: Report on management of 4 cases.

We report a series of four patients aged 4, 5, 14, and 27 years (1 male and 3 female patients) with severe shortening of the neck and torticollis since early childhood who presented with complaint of pain in the nape of neck as the primary symptom. All four patients had relatively well preserved neurological functions. One patient had vertical mobile and reducible atlantoaxial dislocation, and 3 patients had anteroposterior mobile and reducible dislocation. There was assimilation of atlas in 1 patient. The arch of atlas was bifid in 3 patients. Two patients underwent atlantoaxial fixation. Both the patients were relieved of neck pain after their surgery. The potential surgical difficulties due to the presence of severe shortening of neck height and marginal presenting symptoms favored conservative observation in the other 2 patients. Follow-up ranged from 6 to 84 months. All patients are functionally and socially active.