Researchers conducted retrospective radiologic and clinical comparative research at Level III. For a study, they sought to examine the outcomes of pedicle subtraction osteotomy (PSO) in adults with fixed versus flexible sagittal imbalance. About 61 patients who had PSO were enrolled in the study, with a minimum follow-up of 2 years. Ankylosing spondylitis and iatrogenic flatback deformity caused a permanent imbalance in 21 patients, while degenerative spinal deformity and posttraumatic kyphosis caused a flexible imbalance in 40 patients. The fixed group’s mean age was somewhere between 54.9 and 9.2 years, while the flexible group’s mean age was somewhere between 65.9 and 10.5 years (P<0.01). PSO corrected the kyphotic angle by roughly 35 degrees in both groups, but the flexible group’s loss of correction (LOC) was more significant. Lumbar Lordosis correction was similar in both groups, at somewhere between 31.7 and 15.4 degrees in the fixed group and somewhere between 32.3 and 20.8 degrees in the flexible group. However, the LOC was also more significant in the elastic group, somewhere between 9.8 and 12.4 and somewhere between 2.7 and 3.5 degrees, respectively (P<0.01). In addition, the fixed group had significantly better sagittal vertical axis restoration than the flexible group (P=0.002). Postoperative sequelae included neurological impairment and screw loosening in 4 patients in the fixed group and proximal junctional kyphosis, screw pullout, rod fracture, and pseudarthrosis in 15 patients in the flexible group. Compared to the fixed deformity, PSO for flexible sagittal imbalance resulted in a larger LOC of the osteotomy angle, Lumbar Lordosis, and sagittal vertical axis. Furthermore, the loose group experienced more significant problems, such as implant failure.
