Preop Spine Degeneration Influences Adjacent Segment Degeneration

What sort of degenerative radiographic changes occur at segments adjacent to the site of an anterior cervical fusion? Researchers from George Washington University and the Medical College of Wisconsin set out to determine that and more. For their study, the team followed 136 patients who underwent anterior cervical discectomy and fusion for symptomatic cervical spondylosis or disc herniation.

Raj Rao, M.D. is professor of Orthopaedic Surgery and Neurosurgery and chairman of the Department of Orthopaedic Surgery at George Washington University. He told OTW, “There are several studies that have looked into degeneration of adjacent segments following anterior cervical fusion, bur only a few that have looked solely at the nature of the long term radiographic consequences of anterior cervical fusion. Our investigation of a large number of patients over a 5-30 year period (average 12.7 year follow up) provides outstanding insight into the types of radiographic changes we may expect at motion segments adjacent to a fusion in the cervical spine. We know that some of these radiographic changes will be symptomatic, so our study also provides some insight into the history of degenerative progression at these spinal segments and what our patients may expect, over time, following anterior cervical fusion.”

“Degenerative changes at levels adjacent to a fusion can be influenced by multiple factors, including the extent of preoperative degeneration at the level, how close a level is to the fusion, and the time elapsed since the fusion. It is interesting to learn that the age of the patient did not affect adjacent segment disease, nor did the number of segments fused or the sagittal alignment of the fusion.”

“Spine surgeons have traditionally included an adjacent segment in the fusion when it shows degenerative changes. Our study shows that we may need to revisit this thinking. Adjacent segments that show significant degeneration (and do not appear to be clinically symptomatic) may be relatively stable, and do not necessarily undergo more rapid degeneration because of the fusion.”

“Anterior cervical fusion remains one of the most effective operations I do for my patients, and I will continue to offer this as the primary option for patients who have intractable cervical radiculopathy or myelopathy. This investigation helps me in selecting levels that ought to be included in the fusion, and allows me to better inform my patients about the long-term consequences of these operations.”