Archive | 2019
Adjacent-Level Disease: Fact and Fiction
Abstract
The topics of adjacent segment (AS) degeneration and disease have been increasingly discussed with the development and adoption of motion preserving devices. AS degeneration is defined as new degenerative radiographic changes at a spinal level immediately above or below surgically treated levels. When this degeneration is associated with clinical symptoms, including radiculopathy, myelopathy, or mechanical instability, then the appropriate terminology is AS disease. Controversy exists as to whether AS disease is primarily due to the natural progression of an underlying degenerative process or an accelerated process due to increased forces placed on adjacent segments following fusion surgery. In theory, motion preserving devices would eliminate or significantly decrease any accelerated degeneration related to fusion and increased biomechanical stress. Both clinical and laboratory studies have addressed AS degeneration and disease as well as the factors leading to their development. In this chapter, we will review these studies as well as examine the evidence basis regarding the effect of motion preservation technology on the incidence of AS disease. J. Parish (*) ยท D. Coric Department of Neurological Surgery, Carolinas Medical Center, Charlotte, NC, USA