What are the significant factors associated with adjacent segment disease in short-segment lumbar spinal fusion? A retrospective cohort analysis of cases with at least 2 years of follow-up at a single center, 2005–2015

go short-level lumbar spinal fusion surgery through a retrospective cohort analysis focused on spinopelvic parameters. Methods: A retrospective cohort study was conducted of 117 patients who underwent short-level lumbar spinal fusion surgery from January 2005 to December 2015. The patients were divided into 2 groups (control [non-ASD] and ASD) at a 1:1 ratio, with 28 patients per group. Spinopelvic parameters were analyzed on radiographs. Risk factors, such as Pfirrmann grade, age, and osteoporosis were also used to compare the 2 groups. Results: No significant difference was found between the ASD group and the control group in baseline demographic characteristics. The Pfirrmann grade was higher in the ASD group (P=0.022). The spinopelvic parameters with statistically significant differences between the 2 groups were lumbar lordosis (LL) and pelvic incidence (PI)-LL. The LL of the control group was higher than that of the ASD group (preoperation, P=0.022; postoperation, P=0.012). The PI-LL value was smaller in the control group than in the ASD group (preoperation, P=0.043; postoperation, P=0.042). Conclusion: LL, PI-LL, and the Pfirrmann grade were correlated with the incidence of ASD. Therefore, it is important for spinal surgeons to consider patients’ image profiles related to sagittal imbalance and lumbar disc status when planning short-level lumbar spinal fusion.