Adjacent segment disease after lumbar spinal fusion: A systematic review of the current literature

The objectives are to comprehensively define adjacent segment disease; highlight advances in the approach to spinal disorders, present the identified risk factors; examine outcomes; and summarize current recommendations. The literature supports previous degeneration and altered biomechanics of the spine as causes of adjacent segment disease. Excessive facet degeneration is a risk factor. Clinical outcome scores show improvement irrespective of procedure type. The number of spinal segments fused, fusion level, and age yield conflicting reports regarding their contribution to adjacent segment disease. Arthroplasty, dynamic stabilization, and interspinous process implants are effective in decreasing incidence.