The Effect of Rod Bending on Long-term Lumbar Sagittal Parameters in Spondylolisthesis Patients Treated With Short Segment Posterior Fusion: A Randomized Clinical Trial

Background and Aim: Although rod bending is a universal method for maintaining lumbar lordosis (LL), its long-term efficacy in short-segment posterior fusion is still a challenge. This study aimed at evaluating the long-term effect of rod bending in patients with grade one L4/L5 spondylolisthesis with a short segment fusion. Methods and Materials/Patients: A double-blind prospective randomized clinical trial was conducted from 2016 to 2018 and patients who met the inclusion criteria were enrolled in the study. The participants were randomized into two treatment arms: open posterior fusion with rod bending and without rod bending. The baseline data, including leg and back pain scores, were evaluated before surgery. Lumbar, focal, and segmental lordosis were measured before surgery. After surgery and a one-year follow-up, pain scores and lordosis measurements were re-evaluated and compared between and within groups. Results: A total of 60 patients were analyzed. Leg and back pain scores improved significantly after the follow-up in both groups (P<0.0001). However, there was no significant difference between the two groups before and after the surgery. LL did not change in either group after surgery. Focal and segmental lordosis significantly increased in both groups but showed no difference between the groups at either time. Complications were not significantly different in either group. Conclusion: In this study, no significant difference concerning the radiological and pain outcomes was observed in either group; therefore, rod bending to reach the desired LL may be an unnecessary spend of time.