en ستون فقرات Spine surgery پژوهشی Research Article <strong>Background</strong>: Revision long-segment posterior spinal fusion (PSF) for complex degenerative spinal deformity is technically demanding and associated with significant perioperative risks. Whether a one-stage or two-stage strategy yields superior outcomes remains controversial. Objectives: In this study, we aimed to compare radiologic outcomes, perioperative parameters, and complication rates between one-stage and two-stage revision of long-segment PSF.<br> <strong>Methods</strong>: We retrospectively reviewed 45 patients who underwent revision long-segment PSF at our tertiary center between 2021 and 2023. Patients were divided into one-stage (n=29) and two-stage (n=16) groups. Demographic, perioperative, and imaging parameters, as well as complication rates, were compared between groups.&nbsp;<br> <strong>Results</strong>: Both groups demonstrated significant improvement in sagittal and coronal alignment, with no statistically significant differences in radiologic outcomes. Operative time (P=0.038) and hemoglobin drop (P=0.001) were significantly greater in the two-stage group. Hospital stay tended to be longer in staged procedures, though the difference was not statistically significant. Overall complication rates were comparable between the groups (48.3% vs 37.5%, P=0.544), with infection being the most common complication in both groups (17.2% vs 18.7%).<br> <strong>Conclusion</strong>: One-stage and two-stage revision long-segment PSF achieved comparable radiologic outcomes and complication rates. However, the one-stage approach was associated with shorter operative time and reduced hemoglobin drop. These findings suggest that single-stage revision surgery may provide favorable perioperative outcomes without compromising safety. Revision surgery, Long-segment, Posterior spinal fusion (PSF), Spinal deformity, One stage, Two stage, Complications, Outcomes 57 64 http://jros.iums.ac.ir/browse.php?a_code=A-10-2704-1&slc_lang=en&sid=1 Mohammadreza Chehrassan morchehrasan@yahoo.com 10031947532846008337 10031947532846008337 No Department of Orthopedics, Bone and Joint Reconstruction Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. Farshad Nikouei nikouei.f@iums.ac.ir 10031947532846008338 10031947532846008338 No Department of Orthopedics, Bone and Joint Reconstruction Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. Mohammadreza Shakeri mshakeri3116@gmail.com 10031947532846008339 10031947532846008339 No Department of Orthopedics, Bone and Joint Reconstruction Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. Gholamreza Azarnia razarnia65@gmail.com 10031947532846008340 10031947532846008340 No Department of Orthopedics, Bone and Joint Reconstruction Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. Reza Ahmadi Reza3732@gmail.com 10031947532846008341 10031947532846008341 Yes Department of Orthopedics, Bone and Joint Reconstruction Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. Ehsan Ghavidel ghavidele@gmail.com 10031947532846008342 10031947532846008342 No Department of Orthopedics, Bone and Joint Reconstruction Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. Ebrahim Ameri Mahabadi ameri.e@iums.ac.ir 10031947532846008343 10031947532846008343 No Department of Orthopedics, Bone and Joint Reconstruction Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran. Hasan Ghandhari ghandhari.h@iums.ac.ir 10031947532846008344 10031947532846008344 No Department of Orthopedics, Bone and Joint Reconstruction Research Center, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.