How is superior migration of the odontoid treated in patients with rheumatoid arthritis (RA) of the cervical spine?

Updated: Aug 13, 2019
  • Author: Steven R Garfin, MD; Chief Editor: Jeffrey A Goldstein, MD  more...
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Even in the absence of neurologic deficit, patients with any degree of basilar invagination should have an MRI study in flexion to evaluate spinal cord compression. Surgical treatment should be considered in any patient with cord compression or neurologic deficit. Preoperatively, cervical traction can be used to attempt a gradual reduction.

Occipitocervical fusion is the procedure of choice in patients with SMO. Several devices have been described, ranging from wire loops securing tricortical bone graft supplemented with cement or metal mesh, contoured rods, and more recently, plates and screws (see the image below). [64, 65]

Rheumatoid spondylitis. Occipitocervical fusion co Rheumatoid spondylitis. Occipitocervical fusion combined with lateral mass plating for a patient with combined superior migration of the odontoid and subaxial subluxation. Courtesy of Steven R. Garfin.

The more rigid fixation afforded by plating has been associated with a lower pseudarthrosis rate when compared with wiring techniques. [66]  Occipitocervical fusion with plating generally involves screw placement into the C2 pedicles under fluoroscopic guidance through a precontoured plate. This allows easier subsequent placement of subaxial screws in the lateral masses and in the occiput. Screws are usually not placed above the inion to avoid the intracranial venous sinuses.

Although the inner table can be thin in places, holes drilled 2-3 cm from the midline, halfway between the foramen magnum and the transverse sinus, are generally safe. No matter which implant technique is used, autologous bone grafting should always be performed. If the deformity is irreducible in traction, decompression either posteriorly or anteriorly (based on the location of the compression) should be considered as an adjunct to the fusion, as discussed above. Anterior compression in these patients is predominantly osseous, not from synovial pannus. Therefore, a ventral route provides more reliable decompression.

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