{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,11]],"date-time":"2026-10-11T03:41:50Z","timestamp":1791690110390,"version":"4.3.4"},"reference-count":50,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","issue":"6","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2025,6,1]]},"abstract":"<jats:sec>\n                    <jats:title>OBJECTIVE<\/jats:title>\n                    <jats:p>Appropriate distribution of the upper and lower arcs of lordosis after adult spinal deformity (ASD) surgery is important in achieving a harmonious spinal shape. In a cohort of patients undergoing ASD surgery, the authors aimed to determine the impact of the preoperative and postoperative upper and lower arcs of lordosis on any mechanical complication, proximal junctional kyphosis (PJK) and proximal junctional failure (PJF), and reoperation for mechanical complications.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>METHODS<\/jats:title>\n                    <jats:p>A single-institution retrospective cohort study of patients who underwent ASD surgery from 2009 to 2021 was performed. Inclusion criteria were \u2265 5-level fusion, sagittal\/coronal deformity, and 2-year follow-up data. The primary exposure variables were the preoperative and postoperative upper and lower lordosis arc angles, as described by Roussouly. Postoperative outcomes included mechanical complications and reoperations, and a separate analysis was performed for PJK\/PJF. A bivariate analysis was performed, as well as a multivariable logistic regression analysis controlling for age, sex, BMI, preoperative type of malalignment, interbody fusion type, and osteoporosis.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>RESULTS<\/jats:title>\n                    <jats:p>Among the 184 patients (140 females, mean age \u00b1 SD 68.6 \u00b1 11.3 years) undergoing ASD surgery who were included, the mean number of instrumented levels was 10.6 \u00b1 3.1. While the upper lordosis arc increased from before to after surgery (11.4\u00b0 \u00b1 8.8\u00b0 to 18.5\u00b0 \u00b1 13.7\u00b0, p &lt; 0.001), the lower lordosis arc did not significantly increase (26.0\u00b0 \u00b1 14.3\u00b0 to 28.0\u00b0 \u00b1 14.5\u00b0, p = 0.285). Preoperatively, a smaller upper lordosis arc (8.9\u00b0 \u00b1 8.6\u00b0 vs 12.1\u00b0 \u00b1 8.8\u00b0, p = 0.046), lower lordosis arc (22.0\u00b0 \u00b1 12.2\u00b0 vs 27.1\u00b0 \u00b1 14.6\u00b0, p = 0.049), and total lordosis angle (30.9\u00b0 \u00b1 14.9\u00b0 vs 39.1\u00b0 \u00b1 17.3\u00b0, p = 0.008) were found in patients who had PJK\/PJF that required reoperation compared with those who did not undergo reoperation for PJK\/PJF. A smaller preoperative lower lordosis arc was found in patients with pseudarthrosis (21.7\u00b0 \u00b1 12.4\u00b0 vs 27.9\u00b0 \u00b1 14.6\u00b0, p = 0.006) and reoperation due to mechanical complications (22.7\u00b0 \u00b1 12.3\u00b0 vs 27.9\u00b0 \u00b1 15.0\u00b0, p = 0.018) compared to those without. Postoperatively, a smaller postoperative lower lordosis arc was found in patients with mechanical complications requiring reoperation (24.5\u00b0 \u00b1 16.8\u00b0 vs 30.0\u00b0 \u00b1 12.8\u00b0, p = 0.014) and pseudarthrosis (23.9\u00b0 \u00b1 17.4\u00b0 vs 29.8\u00b0 \u00b1 12.6\u00b0, p = 0.011). In the multivariable logistic regression analysis, a smaller preoperative lower lordosis arc was associated with total mechanical complications (OR 0.97, 95% CI 0.94\u20130.99; p = 0.006), PJK\/PJF requiring reoperation (OR 0.97, 95% CI 0.94\u20131.00; p = 0.021), and mechanical complication requiring reoperation (OR 0.97, 95% CI 0.95\u20130.99; p = 0.006). Postoperatively, a smaller lower lordosis arc was associated with mechanical complications requiring reoperations (OR 0.97, 95% CI 0.94\u20130.99; p = 0.014).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>CONCLUSIONS<\/jats:title>\n                    <jats:p>A smaller preoperative and postoperative lower lordosis arc increased the odds of several mechanical complications and reoperation. No such relationship was found with the upper arc. Efforts should be made to increase the lower arc of lordosis to avoid false Roussouly types, mechanical complications, and reoperation.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3171\/2025.3.focus2576","type":"journal-article","created":{"date-parts":[[2025,6,1]],"date-time":"2025-06-01T05:55:07Z","timestamp":1748757307000},"page":"E7","source":"Crossref","is-referenced-by-count":10,"title":["Is the upper arc or lower arc of lordosis more important in avoiding mechanical complications after adult spinal deformity surgery?"],"prefix":"10.3171","volume":"58","author":[{"given":"Harsh","family":"Jain","sequence":"first","affiliation":[{"name":"Departments of Neurological Surgery and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Iyan","family":"Younus","sequence":"additional","affiliation":[{"name":"Departments of Neurological Surgery and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lakshmi Suryateja","family":"Gangavarapu","sequence":"additional","affiliation":[{"name":"Vanderbilt University, School of Medicine, Nashville, Tennessee; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hani","family":"Chanbour","sequence":"additional","affiliation":[{"name":"Departments of Neurological Surgery and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ranbir","family":"Ahluwalia","sequence":"additional","affiliation":[{"name":"Departments of Neurological Surgery and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tyler","family":"Zeoli","sequence":"additional","affiliation":[{"name":"Departments of Neurological Surgery and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Adam M.","family":"Wegner","sequence":"additional","affiliation":[{"name":"OrthoVirginia, Arlington, Virginia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Julian G.","family":"Lugo-Pico","sequence":"additional","affiliation":[{"name":"Departments of Neurological Surgery and"},{"name":"Orthopedic Surgery, Vanderbilt University Medical Center, Nashville;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Amir M.","family":"Abtahi","sequence":"additional","affiliation":[{"name":"Departments of Neurological Surgery and"},{"name":"Orthopedic Surgery, Vanderbilt University Medical Center, Nashville;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Byron F.","family":"Stephens","sequence":"additional","affiliation":[{"name":"Departments of Neurological Surgery and"},{"name":"Orthopedic Surgery, Vanderbilt University Medical Center, Nashville;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"and Scott L.","family":"Zuckerman","sequence":"additional","affiliation":[{"name":"Departments of Neurological Surgery and"},{"name":"Orthopedic Surgery, Vanderbilt University Medical Center, Nashville;"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1754","reference":[{"issue":"1 Suppl","key":"b1","series-title":"Global Spine J","first-page":"8S","article-title":"Evolution and advancement of adult spinal deformity research and clinical care: an overview of the Scoli-RISK-1 Study","volume":"9","author":"Cerpa M","year":"2019","unstructured":"Cerpa M, Lenke LG, Fehlings MG, Shaffrey CI, Cheung KMC, Carreon LY. Evolution and advancement of adult spinal deformity research and clinical care: an overview of the Scoli-RISK-1 Study. Global Spine J. 2019;9(1 Suppl):8S-14S."},{"issue":"5","key":"b2","series-title":"J Neurosurg Spine","first-page":"540","article-title":"Comprehensive study of back and leg pain improvements after adult spinal deformity surgery: analysis of 421 patients with 2-year follow-up and of the impact of the surgery on treatment satisfaction","volume":"22","author":"Scheer JK","year":"2015","unstructured":"Scheer JK, Smith JS, Clark AJ,  Comprehensive study of back and leg pain improvements after adult spinal deformity surgery: analysis of 421 patients with 2-year follow-up and of the impact of the surgery on treatment satisfaction. J Neurosurg Spine. 2015;22(5):540\u2013553."},{"issue":"4","key":"b3","series-title":"J Neurosurg Spine","first-page":"607","article-title":"International Spine Study Group Outcomes of operative treatment for adult spinal deformity: a prospective multicenter assessment with mean 4-year follow-up","volume":"37","author":"Elias E","year":"2022","unstructured":"Elias E, Bess S, Line B,  International Spine Study Group Outcomes of operative treatment for adult spinal deformity: a prospective multicenter assessment with mean 4-year follow-up. J Neurosurg Spine. 2022;37(4):607\u2013616."},{"issue":"18","key":"b4","series-title":"Spine (Phila Pa 1976)","first-page":"1414","article-title":"Radiographical and implant-related complications in adult spinal deformity surgery: incidence, patient risk factors, and impact on health-related quality of life","volume":"40","author":"Soroceanu A","year":"2015","unstructured":"Soroceanu A, Diebo BG, Burton D,  Radiographical and implant-related complications in adult spinal deformity surgery: incidence, patient risk factors, and impact on health-related quality of life. Spine (Phila Pa 1976). 2015;40(18):1414\u20131421."},{"issue":"2","key":"b5","series-title":"Spine J","first-page":"337","article-title":"Long term mechanical failure in well aligned adult spinal deformity patients","volume":"25","author":"Haddad S","year":"2025","unstructured":"Haddad S, Yilgor C, Jacobs E,  Long term mechanical failure in well aligned adult spinal deformity patients. 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Eur Spine J. 2024;33(2):610\u2013619."},{"issue":"17","key":"b13","series-title":"Spine (Phila Pa 1976)","first-page":"1187","article-title":"Lumbar lordosis redistribution and segmental correction in adult spinal deformity: does it matter?","volume":"49","author":"Diebo BG","year":"2024","unstructured":"Diebo BG, Balmaceno-Criss M, Lafage R,  Lumbar lordosis redistribution and segmental correction in adult spinal deformity: does it matter? Spine (Phila Pa 1976). 2024;49(17):1187\u20131194."},{"issue":"5","key":"b14","series-title":"Spine Deform","first-page":"1027","article-title":"Surgical correction of adult spinal deformity in accordance to the Roussouly classification: effect on postoperative mechanical complications","volume":"8","author":"Bari TJ","year":"2020","unstructured":"Bari TJ, Hansen LV, Gehrchen M. Surgical correction of adult spinal deformity in accordance to the Roussouly classification: effect on postoperative mechanical complications. Spine Deform. 2020;8(5):1027\u20131037."},{"issue":"2","key":"b15","series-title":"Eur Spine J","first-page":"741","article-title":"The predictive power of the Roussouly classification on mechanical complications after surgery for adult spinal deformity: systematic review and meta-analysis","volume":"34","author":"Aoun M","year":"2025","unstructured":"Aoun M, Daher M, Daniels AH, Kreichati G, Kharrat K, Sebaaly A. The predictive power of the Roussouly classification on mechanical complications after surgery for adult spinal deformity: systematic review and meta-analysis. Eur Spine J. 2025;34(2):741\u2013747."},{"issue":"9","key":"b16","series-title":"Eur Spine J","first-page":"1459","article-title":"Sagittal balance of the pelvis-spine complex and lumbar degenerative diseases. A comparative study about 85 cases","volume":"16","author":"Barrey C","year":"2007","unstructured":"Barrey C, Jund J, Noseda O, Roussouly P. Sagittal balance of the pelvis-spine complex and lumbar degenerative diseases. A comparative study about 85 cases. Eur Spine J. 2007;16(9):1459\u20131467."},{"issue":"2","key":"b17","series-title":"Neurosurg Clin N Am","first-page":"213","article-title":"Proximal junctional kyphosis and proximal junctional failure","volume":"24","author":"Hart RA","year":"2013","unstructured":"Hart RA, McCarthy I, Ames CP, Shaffrey CI, Hamilton DK, Hostin R. Proximal junctional kyphosis and proximal junctional failure. Neurosurg Clin N Am. 2013;24(2):213\u2013218."},{"issue":"17","key":"b18","series-title":"Spine (Phila Pa 1976)","first-page":"2017","article-title":"Altered patterns of superficial trunk muscle activation during sitting in nonspecific chronic low back pain patients: importance of subclassification","volume":"31","author":"Dankaerts W","year":"2006","unstructured":"Dankaerts W, O\u2019Sullivan P, Burnett A, Straker L. Altered patterns of superficial trunk muscle activation during sitting in nonspecific chronic low back pain patients: importance of subclassification. Spine (Phila Pa 1976). 2006;31(17):2017\u20132023."},{"issue":"Suppl 3","key":"b19","series-title":"Eur Spine J","first-page":"S324","article-title":"Ageing and degenerative changes of the intervertebral disc and their impact on spinal flexibility","volume":"23","author":"Galbusera F","year":"2014","unstructured":"Galbusera F, van Rijsbergen M, Ito K, Huyghe JM, Brayda-Bruno M, Wilke HJ. Ageing and degenerative changes of the intervertebral disc and their impact on spinal flexibility. Eur Spine J. 2014;23Suppl 3:S324-332."},{"issue":"11","key":"b20","series-title":"Spine J","first-page":"1913","article-title":"Even mild intervertebral disc degeneration reduces the flexibility of the thoracic spine: an experimental study on 95 human specimens","volume":"22","author":"Liebsch C","year":"2022","unstructured":"Liebsch C, Wilke HJ. Even mild intervertebral disc degeneration reduces the flexibility of the thoracic spine: an experimental study on 95 human specimens. Spine J. 2022;22(11):1913\u20131921."},{"issue":"16","key":"b21","series-title":"Spine (Phila Pa 1976)","first-page":"1145","article-title":"Upper versus lower lumbar lordosis corrections in relation to pelvic tilt \u2013 an essential element in surgical planning for sagittal plane deformity","volume":"47","author":"Kim HJ","year":"2022","unstructured":"Kim HJ, Alluri RK, Lafage R,  Upper versus lower lumbar lordosis corrections in relation to pelvic tilt \u2013 an essential element in surgical planning for sagittal plane deformity. Spine (Phila Pa 1976). 2022;47(16):1145\u20131150."},{"key":"b22","series-title":"World Neurosurg","first-page":"e219","article-title":"Restoring L4-S1 lordosis shape in severe sagittal deformity: impact of correction techniques on alignment and complication profile","volume":"189","author":"Singh M","year":"2024","unstructured":"Singh M, Balmaceno-Criss M, Daher M,  Restoring L4-S1 lordosis shape in severe sagittal deformity: impact of correction techniques on alignment and complication profile. World Neurosurg. 2024;189:e219\u2013e229."},{"issue":"9","key":"b23","series-title":"Clin Spine Surg","first-page":"E466","article-title":"Correlation between postoperative distribution of lordosis and reciprocal progression of thoracic kyphosis and occurrence of proximal junctional kyphosis following surgery for adult spinal deformity","volume":"31","author":"Ohba T","year":"2018","unstructured":"Ohba T, Ebata S, Oba H, Koyama K, Haro H. 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J Neurosurg Spine. 2019;30(1):69\u201377."},{"issue":"1","key":"b25","series-title":"Spine Deform","first-page":"121","article-title":"Sagittal age-adjusted score (SAAS) for adult spinal deformity (ASD) more effectively predicts surgical outcomes and proximal junctional kyphosis than previous classifications","volume":"10","author":"Lafage R","year":"2022","unstructured":"Lafage R, Smith JS, Elysee J,  Sagittal age-adjusted score (SAAS) for adult spinal deformity (ASD) more effectively predicts surgical outcomes and proximal junctional kyphosis than previous classifications. Spine Deform. 2022;10(1):121\u2013131."},{"issue":"1 Suppl","key":"b1","series-title":"Global Spine J","first-page":"8S","article-title":"Evolution and advancement of adult spinal deformity research and clinical care: an overview of the Scoli-RISK-1 Study","volume":"9","author":"Cerpa M","year":"2019","unstructured":"Cerpa M, Lenke LG, Fehlings MG, Shaffrey CI, Cheung KMC, Carreon LY. Evolution and advancement of adult spinal deformity research and clinical care: an overview of the Scoli-RISK-1 Study. Global Spine J. 2019;9(1 Suppl):8S-14S."},{"issue":"5","key":"b2","series-title":"J Neurosurg Spine","first-page":"540","article-title":"Comprehensive study of back and leg pain improvements after adult spinal deformity surgery: analysis of 421 patients with 2-year follow-up and of the impact of the surgery on treatment satisfaction","volume":"22","author":"Scheer JK","year":"2015","unstructured":"Scheer JK, Smith JS, Clark AJ,  Comprehensive study of back and leg pain improvements after adult spinal deformity surgery: analysis of 421 patients with 2-year follow-up and of the impact of the surgery on treatment satisfaction. 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J Neurosurg Spine. 2022;37(4):607\u2013616."},{"issue":"18","key":"b4","series-title":"Spine (Phila Pa 1976)","first-page":"1414","article-title":"Radiographical and implant-related complications in adult spinal deformity surgery: incidence, patient risk factors, and impact on health-related quality of life","volume":"40","author":"Soroceanu A","year":"2015","unstructured":"Soroceanu A, Diebo BG, Burton D,  Radiographical and implant-related complications in adult spinal deformity surgery: incidence, patient risk factors, and impact on health-related quality of life. Spine (Phila Pa 1976). 2015;40(18):1414\u20131421."},{"issue":"2","key":"b5","series-title":"Spine J","first-page":"337","article-title":"Long term mechanical failure in well aligned adult spinal deformity patients","volume":"25","author":"Haddad S","year":"2025","unstructured":"Haddad S, Yilgor C, Jacobs E,  Long term mechanical failure in well aligned adult spinal deformity patients. Spine J. 2025;25(2):337\u2013346."},{"issue":"8","key":"b6","series-title":"Eur Spine J","first-page":"2612","article-title":"Recovery following adult spinal deformity surgery: the effect of complications and reoperation in 149 patients with 2-year follow-up","volume":"25","author":"Scheer JK","year":"2016","unstructured":"Scheer JK, Mundis GM, Klineberg E,  Recovery following adult spinal deformity surgery: the effect of complications and reoperation in 149 patients with 2-year follow-up. Eur Spine J. 2016;25(8):2612\u20132621."},{"issue":"6","key":"b7","series-title":"Spine (Phila Pa 1976)","first-page":"445","article-title":"Assessment of adult spinal deformity complication timing and impact on 2-year outcomes using a comprehensive adult spinal deformity classification system","volume":"47","author":"Wick JB","year":"2022","unstructured":"Wick JB, Le HV, Lafage R,  Assessment of adult spinal deformity complication timing and impact on 2-year outcomes using a comprehensive adult spinal deformity classification system. Spine (Phila Pa 1976). 2022;47(6):445\u2013454."},{"issue":"4","key":"b8","series-title":"Neurosurgery","first-page":"559","article-title":"The SRS-Schwab adult spinal deformity classification: assessment and clinical correlations based on a prospective operative and nonoperative cohort","volume":"73","author":"Terran J","year":"2013","unstructured":"Terran J, Schwab F, Shaffrey CI,  The SRS-Schwab adult spinal deformity classification: assessment and clinical correlations based on a prospective operative and nonoperative cohort. Neurosurgery. 2013;73(4):559\u2013568."},{"issue":"1","key":"b9","series-title":"Spine (Phila Pa 1976)","first-page":"62","article-title":"Defining spino-pelvic alignment thresholds: should operative goals in adult spinal deformity surgery account for age?","volume":"41","author":"Lafage R","year":"2016","unstructured":"Lafage R, Schwab F, Challier V,  Defining spino-pelvic alignment thresholds: should operative goals in adult spinal deformity surgery account for age? Spine (Phila Pa 1976). 2016;41(1):62\u201368."},{"issue":"19","key":"b10","series-title":"J Bone Joint Surg Am","first-page":"1661","article-title":"Global Alignment and Proportion (GAP) score: development and validation of a new method of analyzing spinopelvic alignment to predict mechanical complications after adult spinal deformity surgery","volume":"99","author":"Yilgor C","year":"2017","unstructured":"Yilgor C, Sogunmez N, Boissiere L,  Global Alignment and Proportion (GAP) score: development and validation of a new method of analyzing spinopelvic alignment to predict mechanical complications after adult spinal deformity surgery. J Bone Joint Surg Am. 2017;99(19):1661\u20131672."},{"issue":"3","key":"b11","series-title":"Spine (Phila Pa 1976)","first-page":"346","article-title":"Classification of the normal variation in the sagittal alignment of the human lumbar spine and pelvis in the standing position","volume":"30","author":"Roussouly P","year":"2005","unstructured":"Roussouly P, Gollogly S, Berthonnaud E, Dimnet J. Classification of the normal variation in the sagittal alignment of the human lumbar spine and pelvis in the standing position. Spine (Phila Pa 1976). 2005;30(3):346\u2013353."},{"issue":"2","key":"b12","series-title":"Eur Spine J","first-page":"610","article-title":"Relationships between lumbar lordosis correction and the change in global tilt (GT) in adult spinal deformity","volume":"33","author":"Pan C","year":"2024","unstructured":"Pan C, Anouar B, Yang Y,  Relationships between lumbar lordosis correction and the change in global tilt (GT) in adult spinal deformity. Eur Spine J. 2024;33(2):610\u2013619."},{"issue":"17","key":"b13","series-title":"Spine (Phila Pa 1976)","first-page":"1187","article-title":"Lumbar lordosis redistribution and segmental correction in adult spinal deformity: does it matter?","volume":"49","author":"Diebo BG","year":"2024","unstructured":"Diebo BG, Balmaceno-Criss M, Lafage R,  Lumbar lordosis redistribution and segmental correction in adult spinal deformity: does it matter? Spine (Phila Pa 1976). 2024;49(17):1187\u20131194."},{"issue":"5","key":"b14","series-title":"Spine Deform","first-page":"1027","article-title":"Surgical correction of adult spinal deformity in accordance to the Roussouly classification: effect on postoperative mechanical complications","volume":"8","author":"Bari TJ","year":"2020","unstructured":"Bari TJ, Hansen LV, Gehrchen M. Surgical correction of adult spinal deformity in accordance to the Roussouly classification: effect on postoperative mechanical complications. 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