Fusion of Odontoid Nonunion Fractures
A sudden or traumatic blow to the base of the skull or upper neck can result in a shear force that fractures the odontoid process. The odontoid process is a peg-like structure of bone that's part of the C2 vertebra. It sticks up inside the C1 vertebra, which is shaped like an open ring.
When the odontoid process breaks, there's nothing to keep the C1 ring-shaped vertebra from sliding forward or back. This type of movement causes excessive load and pressure to the spinal cord. The result can be serious neurologic damage, including paralysis.
One serious complication to injury of the upper cervical spine can is a nonunion fracture of the odontoid fracture. This means that despite treatment, the fracture doesn't heal. Severe motion pain and instability of the cervical spine occur. Surgical fusion with screws, wires, and bone graft may be required.
In this study, surgeons from Vienna, Austria report the long-term results of C1-2 fusion in nine patients with nonunion odontoid fractures. Another term for fusion is arthrodesis. The authors described the surgical procedure used with each patient. The posterior approach (from behind the neck) was used in all cases.
Radiographs (X-rays) and CT scans were used to evaluate the results. Radiographs of the neck during flexion and extension movement were taken three and 12 months after the operation. Imaging like this can be used to find out how solid the fusion is. Movement at the fusion site can be seen if present.
The final results showed that all nine patients had good fusion with improved symptoms and neurologic function. There were a few problems getting good fixation with the screws but these were corrected. After one full year, patients were able to return to their preinjury level of activities and were satisfied with the results.
Patrick Platzer, MD, et al. Posterior Atlanto-Axial Arthrodesis for Fixation of Odontoid Nonunions. In Spine. March 15, 2008. Vol. 33. No. 6. Pp. 624-630.