{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T04:37:26Z","timestamp":1787027846302,"version":"build-2736575974"},"reference-count":29,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2023,12,26]],"date-time":"2023-12-26T00:00:00Z","timestamp":1703548800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"European Spine Study Group"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Children"],"abstract":"<jats:p>Introduction: Surgery to correct spinal deformities in scoliosis involves the use of contoured rods to reshape the spine and correct its curvatures. It is crucial to bend these rods appropriately to achieve the best possible correction. However, there is limited research on how the rod bending process relates to spinal shape in adolescent idiopathic scoliosis surgery. Methods: A retrospective study was conducted using a prospective multicenter scoliosis database. This study included adolescent idiopathic scoliosis patients from the database who underwent surgery with posterior instrumentation covering the T4 to T12 segments. Standing global spine X-rays were used in the analysis. The sagittal Cobb angles between T5 and T11 were measured on the spine. Additionally, the curvature of the rods between T5 and T11 was measured using the tangent method. To assess the relationship between these measurements, the difference between the dorsal kyphosis (TK) and the rod kyphosis (RK) was calculated (\u0394K = TK \u2212 RK). This study aimed to analyze the correlation between \u0394K and various patient characteristics. Both descriptive and statistical analyses were performed to achieve this goal. Results: This study encompassed a cohort of 99 patients, resulting in a total of 198 \u0394K measurements for analysis. A linear regression analysis was conducted, revealing a statistically significant positive correlation between the kyphosis of the rods and that of the spine (r = 0.77, p = 0.0001). On average, the disparity between spinal and rod kyphosis averaged 5.5\u00b0. However, it is noteworthy that despite this modest mean difference, there was considerable variability among the patients. In particular, in 84% of cases, the concave rod exhibited less kyphosis than the spine, whereas the convex rod displayed greater kyphosis than the spine in 64% of cases. It was determined that the primary factor contributing to the flattening of the left rod was the magnitude of the coronal Cobb angle, both before and after the surgical procedure. These findings emphasize the importance of considering individual patient characteristics when performing rod bending procedures, aiming to achieve the most favorable outcomes in corrective surgery. Conclusions: Although there is a notable and consistent correlation between the curvature of the spine and the curvature of the rods, it is important to acknowledge the substantial heterogeneity observed in this study. This heterogeneity suggests that individual patient factors play a significant role in shaping the outcome of spinal corrective surgery. Furthermore, this study highlights that more severe spinal curvatures in the frontal plane have an adverse impact on the shape of the rods in the sagittal plane. In other words, when the scoliosis curve is more pronounced in the frontal plane, it tends to influence the way the rods are shaped in the sagittal plane. This underscores the complexity of spinal deformities and the need for a tailored approach in surgical interventions to account for these variations among patients.<\/jats:p>","DOI":"10.3390\/children11010029","type":"journal-article","created":{"date-parts":[[2023,12,27]],"date-time":"2023-12-27T02:58:12Z","timestamp":1703645892000},"page":"29","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Rod Angulation Relationship with Thoracic Kyphosis after Adolescent Idiopathic Scoliosis Posterior Instrumentation"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8146-5891","authenticated-orcid":false,"given":"Louis","family":"Boissiere","sequence":"first","affiliation":[{"name":"ELSAN, Polyclinique Jean Villar, 53 Avenue Maryse Basti\u00e9, 33520 Bruges, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2852-0230","authenticated-orcid":false,"given":"Anouar","family":"Bourghli","sequence":"additional","affiliation":[{"name":"Spine Surgery Department, King Faisal Specialist Hospital and Research Center, Riyadh 11211, Saudi Arabia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8831-1767","authenticated-orcid":false,"given":"Fernando","family":"Guevara-Villazon","sequence":"additional","affiliation":[{"name":"ELSAN, Polyclinique Jean Villar, 53 Avenue Maryse Basti\u00e9, 33520 Bruges, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0644-7757","authenticated-orcid":false,"given":"Ferran","family":"Pellis\u00e9","sequence":"additional","affiliation":[{"name":"Spine Surgery Unit, Hospital Universitario Val Hebron, 08035 Barcelona, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2252-6647","authenticated-orcid":false,"given":"Ahmet","family":"Alanay","sequence":"additional","affiliation":[{"name":"Department of Orthopaedics and Traumatology, Acibadem University School of Medicine, Istanbul 34750, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2057-2201","authenticated-orcid":false,"given":"Frank","family":"Kleinst\u00fcck","sequence":"additional","affiliation":[{"name":"Research and Development, Schulthess Klinik, 8008 Zurich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7394-9637","authenticated-orcid":false,"given":"Javier","family":"Pizones","sequence":"additional","affiliation":[{"name":"Spine Surgery Unit, Hospital Universitario La Paz, 28046 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9248-3502","authenticated-orcid":false,"given":"C\u00e9cile","family":"Roscop","sequence":"additional","affiliation":[{"name":"Spine Surgery Unit, CHU Pellegrin, 33076 Bordeaux, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9123-1466","authenticated-orcid":false,"given":"Daniel","family":"Larrieu","sequence":"additional","affiliation":[{"name":"ELSAN, Polyclinique Jean Villar, 53 Avenue Maryse Basti\u00e9, 33520 Bruges, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5602-0508","authenticated-orcid":false,"given":"Ibrahim","family":"Obeid","sequence":"additional","affiliation":[{"name":"ELSAN, Polyclinique Jean Villar, 53 Avenue Maryse Basti\u00e9, 33520 Bruges, France"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,12,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"363","DOI":"10.1007\/s00586-015-3968-0","article-title":"Comparison of combined anterior\u2013posterior approach versus posterior-only approach in treating adolescent idiopathic scoliosis: A meta-analysis","volume":"25","author":"Chen","year":"2016","journal-title":"Eur. 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Am."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"e24","DOI":"10.1016\/j.wneu.2018.07.054","article-title":"Fifteen Years and 2530 Patients: The Evolution of Instrumentation, Surgical Strategies, and Outcomes in Adolescent Idiopathic Scoliosis in a Single Institution","volume":"120","author":"Bao","year":"2018","journal-title":"World Neurosurg."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1028","DOI":"10.1007\/s00586-022-07145-7","article-title":"Comparison of four correction techniques for posterior spinal fusion in adolescent idiopathic scoliosis","volume":"31","author":"Pesenti","year":"2022","journal-title":"Eur. Spine J."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"676","DOI":"10.2106\/JBJS.22.00977","article-title":"Spinal Sagittal Alignment Changes during Childhood: Results of a National Cohort Analysis of 1,059 Healthy Children","volume":"105","author":"Pesenti","year":"2023","journal-title":"J. Bone Jt. Surg."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2414","DOI":"10.1007\/s00586-013-2852-z","article-title":"Relationship between thoracic hypokyphosis, lumbar lordosis and sagittal pelvic parameters in adolescent idiopathic scoliosis","volume":"22","author":"Geoffray","year":"2013","journal-title":"Eur. Spine J."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"190","DOI":"10.1007\/s00586-022-07437-y","article-title":"Restoration of thoracic kyphosis in adolescent idiopathic scoliosis with patient-specific rods: Did the preoperative plan match postoperative sagittal alignment?","volume":"32","author":"Thomas","year":"2023","journal-title":"Eur. Spine J."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Schlager, B., Gro\u00dfkinsky, M., Ruf, M., Wiedenh\u00f6fer, B., Akbar, M., and Wilke, H.-J. (2023). Range of surgical strategies for individual adolescent idiopathic scoliosis cases: Evaluation of a multi-centre survey. Spine Deform., Ahead of print.","DOI":"10.1007\/s43390-023-00756-0"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1007\/s00586-006-0063-6","article-title":"Variability of spinal instrumentation configurations in adolescent idiopathic scoliosis","volume":"16","author":"Aubin","year":"2007","journal-title":"Eur. Spine J."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1097\/BSD.0000000000000721","article-title":"Patient-specific Rods for Surgical Correction of Sagittal Imbalance in Adults: Technical Aspects and Preliminary Results","volume":"32","author":"Solla","year":"2019","journal-title":"Clin. Spine Surg. Spine Publ."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1143","DOI":"10.1016\/j.otsr.2019.03.003","article-title":"Mismatch between rod bending and actual post-operative lordosis in lumbar arthrodesis with poly axial screws","volume":"105","author":"Moufid","year":"2019","journal-title":"Orthop. Traumatol. Surg. Res."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"574","DOI":"10.1186\/s13018-020-02115-5","article-title":"Use of the sagittal Cobb* angle to guide the rod bending in the treatment of thoracolumbar fractures: A retrospective clinical study","volume":"15","author":"Shi","year":"2020","journal-title":"J. Orthop. Surg. Res."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"3666","DOI":"10.1007\/s00586-023-07791-5","article-title":"Rod angulation does not reflect sagittal curvature in adult spinal deformity surgery: Comparison of lumbar lordosis and rod contouring","volume":"32","author":"Boissiere","year":"2023","journal-title":"Eur. Spine J."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"115","DOI":"10.1016\/j.clinbiomech.2016.10.002","article-title":"How does differential rod contouring contribute to 3-dimensional correction and affect the bone-screw forces in adolescent idiopathic scoliosis instrumentation?","volume":"39","author":"Wang","year":"2016","journal-title":"Clin. Biomech."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"450","DOI":"10.22603\/ssrr.2020-0190","article-title":"Comments to \u201cUtility of Patient-Specific Rod Instrumentation in Deformity Correction: Single Institution Experience\u201d by Sadrameli et al","volume":"5","author":"Solla","year":"2021","journal-title":"Spine Surg. Relat. Res."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1676","DOI":"10.1007\/s00586-017-4958-1","article-title":"3D rod shape changes in adolescent idiopathic scoliosis instrumentation: How much does it impact correction?","volume":"26","author":"Aubin","year":"2017","journal-title":"Eur. Spine J."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1073","DOI":"10.1016\/j.otsr.2018.07.018","article-title":"Cobalt-chrome and titanium alloy rods provide similar coronal and sagittal correction in adolescent idiopathic scoliosis","volume":"104","author":"Sabah","year":"2018","journal-title":"Orthop. Traumatol. Surg. Res."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"579","DOI":"10.1097\/BRS.0000000000003795","article-title":"Machine Learning Predicts the 3D Outcomes of Adolescent Idiopathic Scoliosis Surgery Using Patient\u2013Surgeon Specific Parameters","volume":"46","author":"Pasha","year":"2021","journal-title":"Spine"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"S14","DOI":"10.1186\/1748-7161-10-S2-S14","article-title":"A new corrective technique for adolescent idiopathic scoliosis: Convex manipulation using 6.35 mm diameter pure titanium rod followed by concave fixation using 6.35 mm diameter titanium alloy","volume":"10","author":"Terai","year":"2015","journal-title":"Scoliosis"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"113","DOI":"10.1016\/S0033-8389(22)02627-6","article-title":"Measurement of spinal curvatures","volume":"13","author":"McAlister","year":"1975","journal-title":"Radiol. Clin. N. 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Am."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"376","DOI":"10.1302\/0301-620X.102B3.BJJ-2019-0993.R1","article-title":"Deformity correction in thoracic adolescent idiopathic scoliosis: A comparison of posteromedial translation using sublaminar bands and cantilever with pedicle screws","volume":"102-B","author":"Pesenti","year":"2020","journal-title":"Bone Jt. J."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"E1264","DOI":"10.1097\/BRS.0000000000003566","article-title":"A 3D Parameter Can Guide Concave Rod Contour for the Correction of Hypokyphosis in Adolescent Idiopathic Scoliosis","volume":"45","author":"Kluck","year":"2020","journal-title":"Spine"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1927","DOI":"10.1007\/s00586-023-07708-2","article-title":"Patient and surgical predictors of 3D correction in posterior spinal fusion: A systematic review","volume":"32","author":"Wan","year":"2023","journal-title":"Eur. Spine J."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"245","DOI":"10.1016\/j.jspd.2018.08.013","article-title":"How to Optimize Axial Correction without Altering Thoracic Sagittal Alignment in Hybrid Constructs with Sublaminar Bands: Description of the \u201cFrame\u201d Technique","volume":"7","author":"Ilharreborde","year":"2019","journal-title":"Spine Deform."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"335","DOI":"10.1097\/00007632-198207000-00003","article-title":"Reciprocal Angulation of Vertebral Bodies in a Sagittal Plane: Approach to References for the Evaluation of Kyphosis and Lordosis","volume":"7","author":"Stagnara","year":"1982","journal-title":"Spine"}],"container-title":["Children"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2227-9067\/11\/1\/29\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T21:42:21Z","timestamp":1760132541000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2227-9067\/11\/1\/29"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,12,26]]},"references-count":29,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2024,1]]}},"alternative-id":["children11010029"],"URL":"https:\/\/doi.org\/10.3390\/children11010029","relation":{},"ISSN":["2227-9067"],"issn-type":[{"value":"2227-9067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,12,26]]}}}