Adjacent Level Degeneration in the Cervical Spine

Cervical arthrodesis is a common and effective procedure for treating cervical disc herniation and spondylosis causing myelopathy and/or radiculopathy. Patients undergoing cervical arthrodesis often have excellent outcomes, although approximately 25% will develop new or recurrent symptoms within 10 years after their index procedures. Whether these recurrent symptoms represent a progression of the initial disease process destined to occur with time or are a consequence of the increased stress associated with the index surgical fusion is still a matter of debate. However, risk factors have been identified that are associated with the development of new disease at adjacent levels, including (1) a single-level index surgical arthrodesis, (2) the presence of adjacent level degeneration at the time of the index surgery, and (3) fusions ending adjacent to the most common levels of cervical degeneration (C5–C6 and C6–C7). Once adjacent level disease has occurred, many patients will require a second surgical procedure either through an anterior, posterior, or combined anterior–posterior approach.