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Transoral approach for revision surgery of os odontoideum with atlantoaxial dislocation.

Revision surgery for os odontoideum with irreducible atlantoaxial dislocation with a transoral approach is not commonly seen. Typically, management of this type of atlantoaxial dislocation is through posterior fixation and fusion or transoral decompression and posterior fusion. This report describes revision surgery in a patient with os odontoideum who was treated with a transoral approach. A 50-year-old man was diagnosed with os odontoideum and atlantoaxial dislocation in 2007 and was treated surgically with posterior occipitocervical internal fixation and fusion. In 2012, he had recurrence of neck pain and numbness of the limbs. Neurologic function was grade D according to the standard neurologic classification of spinal cord injury from the American Spinal Injury Association. Because this was a revision surgery, the internal fixation implant was removed through a posterior approach and a transoral approach was used for release, reduction, internal fixation, and fusion. Two 6-mm cages filled with autogenous bone were introduced into the lateral mass spaces for bony fusion and distraction, and 2 cervical compressive mini-frames were used for fixation. Complete atlantoaxial reduction and decompression of the spinal cord were achieved. The patient reported improvement of symptoms after surgery. Movement of the extremities increased from grade III force to grade V, and neurologic status improved from American Spinal Injury Association grade D to grade E. A transoral approach for release, reduction, bony fusion, and fixation could be an effective procedure for the treatment of os odontoideum with irreducible atlantoaxial dislocation. It provides a new option for bony fusion and internal fixation of the atlantoaxial joint.