Progression of Sagittal Imbalance Predicts Worse Outcomes After Short-segment Lumbar Interbody Fusion

Study Design: Retrospective cohort study. Objective: The purpose of this study was to investigate how the progression of sagittal imbalance after surgery affects clinical outcomes in short-segment lumbar interbody fusion. Summary and Background Data: There are no studies investigated whether the progression of sagittal imbalance after surgery affects clinical outcomes or not. Methods: A total of 578 patients who had undergone short-segment lumbar interbody fusion were reviewed. Postoperative progression of sagittal imbalance was defined as sagittal vertebral axis (SVA) at the final follow-up—postoperative SVA in the present study. Patients were divided into the nonprogression group (ΔSVA<50 mm) and the progression group (ΔSVA ≥50 mm). Spinopelvic parameters and visual analog scale (VAS), Oswestry Disability Index (ODI), Roland-Morris Disability Questionnaire (RDQ), and satisfaction rate were measured preoperatively and at the final follow-up. Results: The nonprogression group included 475 patients, and the progression group included 103 patients. There were significant differences between the 2 groups regarding VAS of low back pain (the nonprogression group vs. the progression group: 19.1 vs. 30.7), ODI (21.3% vs. 29.4%), RDQ (4.6 vs. 6.7), and satisfaction rate (77.7 vs. 63.4) at the final follow-up. Conclusions: The current large cohort study demonstrated that postoperative progression of sagittal imbalance after surgery affects the clinical outcomes in short-segment fusion.