Adjacent Segment Pathology in Spinal Fusion Surgery

Abstract

Study Design: Literature review Objectives: To present up-to-date evidence on adjacent segment pathology (ASP) in spinal fusion surgery Summary of Literature Review: Several prior studies have been conducted on the definition, pathology, etiology, risk factors, and treatment of ASP in spinal fusion surgery. Materials and Methods: Review of the associated literature and latest research. Results: ASP shows various pathologies, including disc degeneration, spondylolisthesis, and instability. Important risk factors are patient-related factors such as high body mass index and a pre-existing degenerated disc at the adjacent level, and surgical-related factors such as facet joint violation due to pedicle screws and changes in sagittal alignment before and after surgery. ASP often cannot be prevented because it is part of the natural history of degeneration. However, to reduce the occurrence after initial surgery, the surgeon should try to reconstruct the spine in a way that maintains balance and avoid injuring adjacent disc, facet joints. Conclusions: ASP should be accurately defined and its pathology and etiology should be accurately identified. Risk factors should also be recognized and avoided during spinal fusion surgery.