Craniovertebral Junction Anomaly with Atlas Assimilation and Reducible Atlantoaxial Dislocation: A Rare Constellation of Bony Abnormalities

A rare case of craniovertebral junction anomaly with associated reducible C 1 -C 2 dislocation and assimilation of the atlas is reported. The patient presented with neck pain with spastic quadriparesis. A posterior stabilization utilizing a contour rod, sublaminar wire fixation and onlay bone grafts between the occiput, and C 3 and C 4 vertebrae was performed followed by symptomatic improvement.