Adjacent Segment Degeneration (ASD) Following Lumber Arthrodesis; Risk Factors and Management.

Abstract

Background Data: Spinal bony fusion is considered to be a good method for treating deformity, trauma, and degenerative lesions. Fusion rates have a good outcome due to improvements in instrumented fixation and bone graft sources. In contrast, numerous complications of fusion surgery may occur and are considered as the predisposing factors for clinical failure after instrumented lumbar fusion. Adjacent segment disease after lumbar spine fusion has been found to occur nowadays with a variable incidence. The risk factors for ASD have not been precisely documented.Purpose: To identify the possible risk factors responsible for adjacent segment affection following lumbosacral fixation and review the literature about their most suitable management. Study Design: A retrospective descriptive clinical case study.Patients and Methods: seventeen patients with lumbosacral fixation for spondylolisthesis or disc degeneration were identified to have de novo adjacent segment degeneration one to four years following fusion surgery. They werestudied as regard age, primary pathology, number of levels and type of fusion and the duration of the lucid interval between the primary surgery and the revision management. Patients were studied radiologically by whole imaging techniques. They were followed up both clinically and radiologically for at least one and half years after revision management. Results: the risk factors include fixation of more than one level, overweight and preexisting facet degeneration in the adjacent segment. The incidence of distal ASD was much lower than that of proximal ASD.Conclusion: longer periods of follow up are needed to determine which of the accused risk factors are responsible for increasing the incidence of ASD and until solid conclusions are established, we should try to minimize the number of riskfactors. (2013ESJ037