Factors Associated with the Incidence of Adjacent Segment Disease after Lumbar Spine Fusion.

BACKGROUND: Adjacent segment disease (ASD) refers to the degeneration that occurs in spinal segments adjacent to a previously fused site, leading to new or recurring symptoms that can affect a patient's quality of life and may require extending fusion to adjacent levels. Understanding ASD risk factors and prevention strategies can enhance patient counseling, risk assessment, and surgical planning, ultimately leading to improved outcomes.OBJECTIVE: This study aims to analyze factors contributing to adjacent segment disease after lumbar spine fusion surgery.METHODS: A retrospective study was conducted on 100 patients: 50 with ASD after lumbar spine fusion (between January 2016 and January 2019) and 50 age-matched controls without ASD. The control group shared the same history of lumbar spine fusion and was followed for at least five years.RESULTS: The ASD group exhibited a significantly greater mean age compared to their non-ASD counterparts (p<0.001). Moreover, the ASD cohort demonstrated a significantly higher body mass index (BMI) (p=0.019). Additionally, data indicated that smoking status correlated with an increased prevalence of ASD (p=0.043). Diabetes was significantly associated with ASD (p=0.005). The fusion of multiple motion segments was significantly associated with ASD (p=0.016). The use of autogenous bone graft in lumbar interbody fusion was associated with higher ASD rates compared to cage insertion (p=0.001).CONCLUSION: Age, obesity, smoking, diabetes, multiple motion segment fusion, and lumbar interbody fusion with autogenous bone graft are potential risk factors for adjacent segment disease after lumbar spine fusion. Reducing these risks may enhance patient outcomes.