Unprecedented complication of odontoid regeneration after transoral odontoidectomy.

Transoral odontoidectomy followed by occipitocervical fixation is a widely used approach to relieve ventral compressions at the craniovertebral junction. Despite the large amount of literature on this approach and its complications, odontoid process regeneration and causing the worsening of symptoms of brainstem dysfunction and upper cervical cord were not found in the English literature. We report the case of odontoid regeneration in a 12-year-old girl. She presented with torticollis and symptoms of brainstem dysfunction and upper cervical cord compression with syringohydromyelia and underwent transoral resection of dens and posterior occipitocervical fusion at the age of 7 years. Post surgery, clinically and radiologically, the resolution was evident till the age of 11 years when the child started to have relapse and worsening of the previous symptoms. The computed tomography/magnetic resonance imaging shows regeneration of the odontoid process compressing the brain stem with an increase in syringohydromyelia. We suggest that there is a need for the removal of the complete odontoid process with periosteum and also beyond the dentocentral synchondrosis to prevent late recurrences of odontoid regeneration.