Banno T, et al. - This retrospective study investigated the prevalence of as well as risk factors for iliac screw loosening following adult spinal deformity surgery. In patients who underwent the operation, iliac screw loosening suggested instability of the lumbosacral junction, causing sagittal malalignment and poor outcomes. The necessary prophylactic steps against complications included accurate screw insertion and restoration of optimal lumbar lordosis [LL].