Minimally Invasive Anterior Cervical Discectomy Without Fusion to Treat Cervical Disc Herniations in Patients with Previous Cervical Fusions.

Adjacent level cervical disc disease and secondarily progressive disc space degeneration that develops years after previously successful anterior cervical fusion at one or more levels is a common, but potentially complex problem to manage. The patient is faced with the option of further open surgery which involves adding another level of disc removal with fusion, posterior decompression, and stabilization, or possibly replacing the degenerated disc with an artificial disc construct. These three cases demonstrate that some patients, especially after minor trauma, may have small herniated discs as the cause for their new symptoms rather than progressive segmental degeneration. Each patient became symptomatic after minor trauma three to six years after the original fusion and had no or minimal radiologic changes of narrowing of the disc or spur formation commonly seen in adjacent level disease, but rather had magnetic resonance imaging (MRI) findings typical of small herniated discs. After failing multiple months of conservative treatment they were offered surgery as an option. Subsequently, all three were successfully treated with minimal anterior discectomy without fusion. There are no reports in the literature of using minimal anterior cervical discectomy without fusion in previous fused patients. This report reviews the background of adjacent level cervical disease, the various biomechanical explanations for developing a new disc herniation rather than progressive segmental degeneration, and how anterior cervical discectomy without fusion can be an option in these patients.