Postoperative Coronal Imbalance Predicts Late Mechanical Failure and Revision Surgery After Adult Spinal Deformity Correction With Pelvic Fixation: A 5-Year Follow-Up Study in Elderly Patients

Postoperative Coronal Imbalance Predicts Late Mechanical Failure and Revision Surgery After Adult Spinal Deformity Correction With Pelvic Fixation: A 5-Year Follow-Up Study in Elderly Patients | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Postoperative Coronal Imbalance Predicts Late Mechanical Failure and Revision Surgery After Adult Spinal Deformity Correction With Pelvic Fixation: A 5-Year Follow-Up Study in Elderly Patients Tomohiro Yamada, Yu Yamato, Tomohiko Hasegawa, Go Yoshida, Tomohiro Banno, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8102655/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 11 You are reading this latest preprint version Abstract Purpose Postoperative coronal imbalance (CIB) is a persistent concern following adult spinal deformity (ASD) surgery. This study aimed to determine whether postoperative CIB independently increases the risk of mechanical complications and revision surgery, and to investigate whether the side of rod fracture correlates with the direction of coronal shift. Methods We retrospectively reviewed 241 patients aged ≥ 65 years who underwent long-segment ASD correction with pelvic fixation between 2010 and 2020. A total of 169 patients (70.1%) completed a minimum 5-year follow-up. Postoperative CIB was defined as C7CSVL > 3 cm. Mechanical complications included proximal junctional kyphosis (PJK), proximal junctional failure (PJF), and rod fracture. Revision surgery was recorded when reoperation was required for painful PJF or rod fracture. Survival analysis was performed using Kaplan–Meier and Cox proportional-hazard models. Results Thirty-four patients (20.1%) exhibited postoperative CIB. Compared with patients without CIB, these patients had greater preoperative coronal deviation (p < 0.001) and longer fusion constructs (9.9 ± 2.3 vs 9.2 ± 2.2 levels; p = 0.007), whereas sagittal vertical axis was comparable (p = 0.876). The incidence of rod fracture (35.3% vs 17.0%; p = 0.034) and revision surgery (35.3% vs 17.8%; p = 0.035) was significantly higher in the CIB group. Kaplan–Meier analysis showed reduced 5-year revision-free survival (HR = 2.0; 95% CI 1.0–4.0; log-rank p = 0.046), with divergence of survival curves evident after 2 years. Rod fractures occurred more frequently on the contralateral side to the direction of coronal shift (61.0%). Conclusions Postoperative coronal imbalance is an independent predictor of late mechanical failure and revision after ASD correction with pelvic fixation in elderly patients. The novel association between coronal shift direction and rod-fracture laterality provides clinical validation of asymmetric mechanical loading, underscoring the importance of precise coronal alignment and side-specific reinforcement to improve long-term construct durability. Level of Evidence: Ⅲ Coronal imbalance Rod fracture Mechanical complications Adult spinal deformity surgery Figures Figure 1 Figure 2 Figure 3 Introduction Adult spinal deformity (ASD) surgery has advanced with the aim of restoring spinopelvic alignment and improving quality of life in elderly patients [1] [2]. While sagittal alignment has been extensively investigated and its restoration is known to correlate with clinical outcomes [3] [4], coronal alignment has received comparatively less attention. Postoperative coronal imbalance (CIB), most commonly defined as a coronal vertical axis (C7CSVL) deviation greater than 3 cm, remains a frequent concern in long fusion surgery for ASD [5]. Several studies have reported associations between postoperative CIB and mechanical complications such as rod fracture (RF), proximal junctional kyphosis (PJK), and proximal junctional failure (PJF) [6] [7]. However, these investigations have included heterogeneous populations across a wide age range, variable fusion levels, and inconsistent use of pelvic fixation [8]. Most reports are also limited to short- or mid-term follow-up (typically two years), leaving uncertainty about whether CIB influences long-term outcomes [9], particularly revision surgery [10]. Furthermore, the independent role of CIB in the development of mechanical complications remains unclear, as many prior analyses did not adequately separate coronal malalignment from sagittal malalignment [5] [11]. From a clinical standpoint, clarification of these issues is important. Revision surgery for mechanical complications places a substantial burden on elderly patients, in whom physiological reserve, bone quality, and tolerance for reoperation are limited [7]. Understanding whether postoperative CIB independently increases the risk of mechanical complications and late revision is critical for surgical planning, risk stratification, and long-term patient counseling. The present study aimed to evaluate the impact of postoperative CIB on the incidence of mechanical complications and revision surgery in elderly patients undergoing ASD surgery with pelvic fixation. With a minimum follow-up of 5 years, this study specifically investigated whether residual CIB influences long-term revision burden independent of sagittal alignment parameters and whether the effect becomes more evident with extended follow-up. We hypothesized that postoperative CIB would be associated with an increased risk of mechanical complications and revision surgery, particularly during long-term follow-up. In addition, we hypothesized that in patients with rod fracture, the fracture would occur more frequently on the side of the coronal shift, reflecting asymmetric load distribution related to residual imbalance. Material and Methods This was a retrospective, single-center study. Patients aged ≥ 65 years who underwent corrective fusion surgery for adult spinal deformity (ASD) with pelvic fixation between 2010 and 2020 were reviewed. Inclusion criteria were availability of whole-spine standing radiographs at baseline and a minimum follow-up duration of 5 years. Postoperative CIB was defined and classified using the first standing whole-spine radiograph obtained within one week after surgery. Patients with incomplete radiographic data or follow-up < 5 years were excluded. The study size was determined by the number of eligible patients available in our institutional database during the study period; no a priori sample size calculation was performed. This study was approved by our local institutional review board (#20–289), which waived the requirement for informed consent due to the retrospective nature of the study. Mechanical complications and revision surgery Mechanical complications of interest included PJK, PJF, and RF. Revision surgery was defined as surgical intervention for PJF or rod fracture in patients who experienced associated pain or functional disturbance. PJK was defined as showing > 20 degrees of kyphosis angle at two levels above the upper instrumented vertebrae [12]. PJF was defined as symptomatic PJK that required surgery. In addition to evaluating overall incidence, we investigated the laterality of rod fracture in relation to the direction of coronal imbalance. For each patient with rod fracture, the fracture side was recorded and compared with the side of the trunk shift measured by C7CSVL Surgical procedure Correction of spinal deformity was performed with the goal of restoring sagittal alignment in accordance with each patient’s intrinsic pelvic incidence, which dictates the optimal target for lumbar lordosis [13]. Rod selection was a 6.0 mm diameter pure titanium rod in all cases. In all cases requiring pelvic fixation, iliac screws were employed as reliable anchors to provide distal stability. Using these anchors, lumbar lordosis was restored through a cantilever technique, which allowed for controlled correction of sagittal malalignment. Concurrently, coronal deformities were addressed using rod translation and rod rotation maneuvers to achieve three-dimensional realignment. This strategy ensured that both sagittal and coronal parameters were corrected in a manner consistent with the patient’s individual spinopelvic morphology, thereby promoting durable mechanical stability and improved clinical outcomes. Intraoperative strategy for coronal balance After completion of corrective maneuvers, intraoperative long-cassette anteroposterior radiographs including the entire spine and pelvis were obtained with the patient in the prone position. The coronal alignment of the C7 plumb line relative to the central sacral vertical line and the leveling of the pelvis were evaluated on these images. Additional rod contouring, compression–distraction adjustment were performed as needed to minimize coronal offset before final tightening. This process was applied systematically to all cases to achieve optimal coronal alignment at the time of fixation. Radiographic assessment and patient reported outcomes Postoperative CIB was defined as C7CSVL > 3 cm in first standing radiograph within postoperative 1 week. Pre- and postoperative sagittal parameters using whole-spine radiographs (anteroposterior and lateral) were collected from patients in the standing position. Lateral radiographs were obtained with the patients gazing horizontally in a natural free-standing posture with their fingers on the clavicles. The following radiograph parameters were assessed: (1) lumbar lordosis (LL), the angle between the upper endplate of the L1 vertebra and the upper endplate of the S1 vertebra; (2) thoracic kyphosis (TK), the angle between the upper endplate of T5 and the lower endplate of T12; (3) sacral slope (SS); (4) pelvic tilt (PT); (5) pelvic incidence (PI); and (6) C7 SVA (the distance between a plum line from the center of the C7 vertebra and the posterior superior center of the sacrum). C7CSVL was defined as the horizontal distance between a vertical plumb line dropped from the center of the C7 vertebral body and the central sacral vertical line. Pre and postoperative patients reported outcomes (PROs), including the Scoliosis Research Society-22 (SRS-22) and Oswestry Disability Index (ODI), were evaluated. Statistical analysis Descriptive statistics are depicted as means and standard deviations and were calculated for the demographic data. Differences in individual parameters were assessed using unpaired t- test, chi-square test, and Fisher’s exact test. Continuous variables were expressed as means ± standard deviations and categorical variables as counts and percentages. Intergroup comparisons (CIB vs. no-CIB) were performed using unpaired t tests, and Fisher’s exact tests for categorical variables. For longitudinal analyses of radiographic parameters and patient-reported outcomes (PROs; SRS-22r and ODI), data obtained after revision surgery were excluded because revision procedures can directly influence spinal alignment and symptom scores. Each patient contributed data to the 1-, 2-, and 5-year evaluations only if they had not undergone revision before that time point. Patients who underwent revision remained included in analyses of mechanical complication incidence, survival analysis, and baseline characteristics. Revision-free survival was assessed using Kaplan–Meier analysis, and differences between groups were evaluated with the log-rank test. Cox proportional-hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for revision surgery associated with postoperative CIB. All statistical analyses were conducted using SPSS software (version 26.0; IBM Corp., Armonk, NY, USA), and statistical significance was set at p < 0.05. Results Among 241 patients who underwent adult spinal deformity surgery with pelvic fixation, 169 (70.1%) had a minimum follow-up of 5 years. Of these, 34 patients (20.1%) demonstrated postoperative CIB, and 135 patients (79.9%) did not (Fig. 1). Baseline demographic characteristics, including age, sex, and body mass index, did not differ significantly between groups. The mean number of fused levels was significantly higher in the CIB group compared with the no-CIB group (9.9 ± 2.3 vs 9.2 ± 2.2, p = 0.007). Preoperative C7CSVL was also greater in the CIB group (p < 0.05) (Table 1). Preoperative spinal alignments showed significantly higher in C7CSVL (p = 0.024) and Cobb angle in the CIB group (p < 0.01) (table 2). Postoperative spinal alignments were comparable between the two groups (table 3). In the CIB group, postoperative C7CSVL was significantly higher compared to in the no-CIB group. Postoperative CIB over time was persistent in the CIB group (Fig. 3). PROs, including SRS-22r total score and ODI, improved significantly from baseline in both groups. However, there were no statistically significant differences between the CIB and no-CIB groups at any postoperative time point (table 4). Mechanical complications Mechanical complication rates were greater in the CIB group (Table 5). PJK occurred in 10 of 34 patients with CIB (29.4%) and 21 of 135 patients without CIB (15.6%, p = 0.082). PJF developed in 4 of 34 patients with CIB (8.9%) and 8 of 135 patients without CIB (5.9%, p = 0.263). RF was identified in of 12 patients with CIB (35.3%) and 23 of 135 patients without CIB (17.0%), with a significant difference between groups (p = 0.034). Revision surgery, was performed in 12 of 34 patients with CIB (35.3%) and 24 of 135 patients without CIB (17.8%, p = 0.035). Kaplan–Meier analysis demonstrated significantly reduced revision-free survival in the CIB group (log-rank p = 0.007). The hazard of revision surgery was higher in patients with CIB compared with those without CIB (HR = 2.5, 95% CI 1.26–5.15). The divergence of survival curves became apparent after 2 years of follow-up, indicating that the increased revision burden in patients with CIB primarily occurred beyond the early postoperative period (Fig. 3). Laterality of Rod Fracture in Relation to Coronal Imbalance A subanalysis was conducted to examine the relationship between the direction of postoperative coronal imbalance and the side of rod fracture. Among the 36 patients who experienced rod fracture during the follow-up period, 22 cases (61.0%) occurred on the contralateral side to the direction of C7CSVL deviation, 10 cases (27.8%) occurred on the ipsilateral side, and 4 cases (11.1%) involved bilateral fractures. Although the difference did not reach statistical significance (p = 0.108), the tendency toward a higher frequency of rod fracture on the contralateral side suggests asymmetric mechanical loading across the construct in the presence of residual coronal imbalance. Discussion In this study, we evaluated the impact of CIB on mechanical complications and revision surgery in elderly patients who underwent long fusion surgery with pelvic fixation for ASD surgery. Patients who exhibited postoperative CIB demonstrated significantly higher rates of rod fracture and revision surgery compared with those who achieved coronal balance, whereas the incidences of PJK and PJF were not statistically different. Kaplan–Meier survival analysis revealed that revision-free survival declined markedly in the CIB group after two years postoperatively, indicating that the detrimental influence of CIB becomes evident in the mid- to long-term period. These findings suggest that even when sagittal alignment parameters such as C7SVA are comparable, residual coronal malalignment independently contributes to increased mechanical stress within the construct, predisposing patients to rod fracture and subsequent revision surgery. The present results underscore the importance of achieving adequate coronal balance at the initial standing position after surgery to prevent delayed mechanical failure in elderly ASD patients undergoing pelvic fixation. Previous studies have described the association between postoperative CIB and mechanical complications following ASD surgery [14], yet most included heterogeneous populations and short-term evaluations. Park et al. demonstrated that postoperative coronal malalignment, defined as C7CSVL > 3 cm, increased the incidence of revision for rod fracture in long-segment fusions extending to the sacrum [15]. Similarly, Zuckerman et al. reported that patients with coronal malalignment had higher rates of major complications, although reoperation rates were not statistically different [16]. These milestone investigations established the clinical relevance of coronal alignment; however, their study populations were primarily middle-aged, the use of pelvic fixation was inconsistent, and the follow-up period was generally limited to two years. Consequently, the long-term impact of postoperative coronal imbalance and its behavior in elderly patients with uniform pelvic fixation have remained uncertain. The present study builds on these earlier findings by focusing specifically on an elderly cohort (≥ 65 years) undergoing ASD correction with pelvic fixation and long-term follow-up of at least five years. This design minimized heterogeneity in distal construct configuration and captured mechanical complications that developed beyond the early postoperative phase. Importantly, the rate of satellite-rod use was comparable between groups, allowing coronal alignment itself to be evaluated independently of construct reinforcement [17], [18]. Despite these modern technical measures, patients with postoperative coronal imbalance exhibited a significantly higher incidence of rod fracture and revision surgery, with a clear divergence in revision-free survival observed after two years. This temporal pattern indicates that the adverse influence of coronal imbalance persists even in stable, multi-rod constructs and becomes more evident over time. Collectively, these findings extend previous knowledge by demonstrating that residual coronal malalignment remains a critical mechanical risk factor in contemporary ASD surgery, particularly in elderly patients whose reduced bone quality and physiological reserve heighten the consequences of late mechanical failure [9]. Despite the higher incidence of mechanical complications and revision surgery in patients with postoperative CIB, PROs, including the SRS-22r and ODI, did not differ significantly between groups. This apparent discrepancy may be partly attributable to the timing of outcome assessment. PROs were collected at predetermined intervals, whereas many revision surgeries occurred beyond two years postoperatively, often between scheduled evaluations. As a result, patients who experienced pain or functional decline preceding revision may not have been captured in the corresponding assessment window, leading to potential underestimation of the true clinical impact of late mechanical failure. Moreover, elderly patients often demonstrate adaptive behavior to progressive imbalance or discomfort, which can attenuate perceived functional decline and diminish sensitivity of questionnaire-based evaluations [19]. Therefore, the absence of a significant difference in PROs should not be interpreted as evidence of equivalent clinical recovery, but rather as a reflection of temporal and reporting bias inherent to long-term follow-up in elderly populations with progressive mechanical complications. Preoperative coronal alignment and fusion length [18] have been recognized as major risk factors for postoperative coronal imbalance. In the present study, patients who developed postoperative CIB showed greater preoperative C7CSVL and longer fusion constructs compared with those who remained balanced. These findings are consistent with previous reports which identified large preoperative coronal offset and lumbosacral fractional-curve rigidity as key predictors of residual malalignment [16, 20]. Likewise, Lewis et al. emphasized the importance of controlling distal coronal tilt, particularly at L4 and L5, to prevent postoperative trunk shift in long pelvic-fixation constructs. [21] Taken together, both our results and prior evidence suggest that the magnitude of preoperative coronal deviation and the complexity inherent to longer fusion spans increase the risk of residual CIB, underscoring the importance of meticulous preoperative planning and intraoperative coronal leveling to optimize global alignment. To our knowledge, this study is the first to analyze the laterality of rod fracture in relation to postoperative coronal imbalance. Among 36 rod fracture cases, fractures occurred more frequently on the contralateral side to the C7CSVL deviation, suggesting that residual coronal malalignment induces asymmetric mechanical loading across the construct. This finding provides clinical evidence supporting the biomechanical concept proposed in prior modeling and technical reports, in which coronal trunk shift generates increased tensile and shear stress on the rod opposite to the direction of deviation, while the ipsilateral rod is primarily subjected to compressive stress [22], [23]. Although previous studies have identified postoperative coronal malalignment as a risk factor for rod fracture and revision surgery, none have quantified side-specific fracture patterns relative to coronal shift direction. The present findings therefore expand current understanding of how residual coronal imbalance contributes not only to the overall risk of mechanical failure but also to its spatial distribution within the construct. Clinically, this insight underscores the need to achieve symmetrical coronal alignment at the time of fixation and to consider targeted reinforcement—such as additional satellite rods or stiffer rod material—on the side anticipated to experience greater tensile stress when a minor residual coronal offset cannot be fully corrected. This study has several limitations that should be acknowledged. First, it was conducted at a single institution, which may limit the generalizability of the findings due to institutional differences in surgical strategy, implant selection, and postoperative management. Second, although the follow-up rate of 70.1% at 5 years was acceptable for a long-term surgical cohort, loss to follow-up may have introduced selection bias. Third, the retrospective design inherently limits causal inference, and unmeasured confounders such as subtle differences in bone quality, muscle mass, or rod contouring technique may have influenced outcomes. Despite these limitations, the uniform surgical indication, consistent use of pelvic fixation, and extended 5-year follow-up strengthen the reliability of the present findings. In conclusion, postoperative CIB as an independent risk factor for long-term mechanical failure and revision surgery in elderly patients undergoing ASD correction with pelvic fixation. Although early postoperative outcomes were comparable between groups, divergence in revision-free survival emerged beyond two years, indicating that the adverse effects of residual coronal malalignment manifest primarily in the mid- to late-term period. A novel subanalysis further revealed that rod fractures occurred predominantly on the contralateral side to the direction of coronal shift, providing clinical validation of asymmetric mechanical loading across the construct. Together, these findings demonstrate that even subtle postoperative coronal imbalance can impose sustained, asymmetric stress on spinal instrumentation, predisposing to late rod fracture and the need for revision. Achieving symmetrical coronal alignment at the time of fixation and considering targeted reinforcement on the tension side may therefore be essential strategies to improve long-term construct durability and reduce revision burden in elderly patients undergoing extensive spinal deformity correction. Declarations Author Contribution Tomohiro Yamada wrote the main manuscript text and prepared all figures ant table. All authors collected data and reviewed the manuscript. References McDowell M, Tempel Z, Gandhoke G, Khattar N, Hamilton D, Kanter A, Okonkwo D (2017) Evolution of Sagittal Imbalance Following Corrective Surgery for Sagittal Plane Deformity. Neurosurgery 81:129. doi: 10.1093/neuros/nyx145 Lee C, Park J-S, Nam Y, Choi Y-T, Park S (2020) Long-term benefits of appropriately corrected sagittal alignment in reconstructive surgery for adult spinal deformity: evaluation of clinical outcomes and mechanical failures. Journal of neurosurgery Spine:1-9. doi: 10.3171/2020.7.SPINE201108 Greenberg J, Whiting B, Martinez O, Butt B, Badhiwala J, Clifton W (2023) Age-Adjusted Alignment Goals in Adult Spinal Deformity Surgery. Seminars in Spine Surgery. doi: 10.1016/j.semss.2023.101027 Ye J-C, Yin T-C, Gupta S, Farooqi A, Wan W, Yilgor C, Sides B, Gupta M (2022) Use of the Global Alignment and Proportion score to predict postoperative health-related quality of life in adult spinal deformity surgery. Journal of neurosurgery Spine:1-8. doi: 10.3171/2022.9.spine22809 Barile F, Ruffilli A, Paolucci A, Viroli G, Manzetti M, Traversari M, Ialuna M, Faldini C (2023) Risk factors for postoperative coronal imbalance after surgical correction of adult spinal deformities: a systematic review with pooled analysis. Journal of neurosurgery Spine:1-15. doi: 10.3171/2023.1.SPINE22669 Tanaka N, Ebata S, Oda K, Oba H, Haro H, Ohba T (2020) Predictors and Clinical Importance of Postoperative Coronal Malalignment After Surgery to Correct Adult Spinal Deformity. Clinical Spine Surgery 33. doi: 10.1097/BSD.0000000000000947 Buell T, Smith J, Shaffrey C, Kim H-J, Klineberg E, Lafage V, Lafage R, Protopsaltis T, Passias P, Mundis G, Eastlack R, Deviren V, Kelly M, Daniels A, Gum J, Soroceanu A, Hamilton D, Gupta M, Burton D, Hostin R, Kebaish K, Hart R, Schwab F, Bess S, Ames C (2020) Multicenter assessment of surgical outcomes in adult spinal deformity patients with severe global coronal malalignment: determination of target coronal realignment threshold. Journal of neurosurgery Spine:1-14. doi: 10.3171/2020.7.SPINE20606 Ploumis A, Simpson A, Cha T, Herzog J, Wood K (2015) Coronal Spinal Balance in Adult Spine Deformity Patients With Long Spinal Fusions: A Minimum 2- to 5-Year Follow-up Study. Journal of Spinal Disorders and Techniques 28:341. doi: 10.1097/BSD.0b013e3182aab2ff Bae J (2021) Commentary on “Characteristics and Risk Factors of Rod Fracture Following Adult Spinal Deformity Surgery: A Systematic Review and Meta-Analysis”. Neurospine 18:455-456. doi: 10.14245/ns.2142816.408 Ishihara M, Taniguchi S, Ono N, Adachi T, Tani Y, Paku M, Kawashima K, Ando M, Saito T (2023) New Effective Intraoperative Techniques for the Prevention of Coronal Imbalance after Circumferential Minimally Invasive Correction Surgery for Adult Spinal Deformity. Journal of Clinical Medicine 12. doi: 10.3390/jcm12175670 Ruffilli A, Barile F, Paolucci A, Manzetti M, Viroli G, Ialuna M, Vita F, Cerasoli T, Faldini C (2023) Independent Risk Factors of Postoperative Coronal Imbalance after Adult Spinal Deformity Surgery. Journal of Clinical Medicine 12. doi: 10.3390/jcm12103559 Bridwell KH, Lenke LG, Cho SK, Pahys JM, Zebala LP, Dorward IG, Cho W, Baldus C, Hill BW, Kang MM (2013) Proximal junctional kyphosis in primary adult deformity surgery: evaluation of 20 degrees as a critical angle. Neurosurgery 72:899-906 Yamato Y, Hasegawa T, Kobayashi S, Yasuda T, Togawa D, Arima H, Oe S, Iida T, Matsumura A, Hosogane N, Matsumoto M, Matsuyama Y (2016) Calculation of the Target Lumbar Lordosis Angle for Restoring an Optimal Pelvic Tilt in Elderly Patients With Adult Spinal Deformity. Spine (Phila Pa 1976) 41:E211-217. doi: 10.1097/brs.0000000000001209 Barone G, Giudici F, Martinelli N, Ravier D, Muzzi S, Minoia L, Zagra A, Scaramuzzo L (2021) Mechanical Complications in Adult Spine Deformity Surgery: Retrospective Evaluation of Incidence, Clinical Impact and Risk Factors in a Single-Center Large Series. J Clin Med 10. doi: 10.3390/jcm10091811 Park JS, Kang DH, Park SJ, Lee CS, Kim HJ (2025) Influence of postoperative coronal malalignment following long-instrumented fusion in patients with adult spinal deformity: evaluation of clinical outcomes and mechanical complications. Spine J. doi: 10.1016/j.spinee.2025.05.010 Zuckerman SL, Lai CS, Shen Y, Lee NJ, Kerolus MG, Ha AS, Buchanan IA, Leung E, Cerpa M, Lehman RA, Lenke LG (2023) Postoperative coronal malalignment after adult spinal deformity surgery: incidence, risk factors, and impact on 2-year outcomes. Spine Deform 11:187-196. doi: 10.1007/s43390-022-00583-9 Yamato Y, Hasegawa T, Yoshida G, Banno T, Oe S, Arima H, Mihara Y, Ushirozako H, Yamada T, Watanabe Y, Ide K, Nakai K, Kurosu K, Matsuyama Y (2022) Revision Surgery for a Rod Fracture with Multirod Constructs Using a Posterior-Only Approach Following Surgery for Adult Spinal Deformity. Asian Spine Journal 16:740-748. doi: 10.31616/asj.2021.0244 Rabinovich E, Buell T, Wang T, Shaffrey C, Smith J (2021) Reduced occurrence of primary rod fracture after adult spinal deformity surgery with accessory supplemental rods: retrospective analysis of 114 patients with minimum 2-year follow-up. Journal of neurosurgery Spine:1-12. doi: 10.3171/2020.12.spine201527 Suijker J, Buurman B, Van Rijn M, Van Dalen M, Ter Riet G, Van Geloven N, De Haan R, Van Charante M, De Rooij S (2014) A simple validated questionnaire predicted functional decline in community-dwelling older persons: prospective cohort studies. Journal of clinical epidemiology 67 10:1121-1130. doi: 10.1016/j.jclinepi.2014.05.014 Ruffilli A, Barile F, Paolucci A, Manzetti M, Viroli G, Ialuna M, Vita F, Cerasoli T, Faldini C (2023) Independent Risk Factors of Postoperative Coronal Imbalance after Adult Spinal Deformity Surgery. J Clin Med 12. doi: 10.3390/jcm12103559 Lewis SJ, Keshen SG, Kato S, Dear TE, Gazendam AM (2018) Risk Factors for Postoperative Coronal Balance in Adult Spinal Deformity Surgery. Global Spine J 8:690-697. doi: 10.1177/2192568218764904 Proietti L, Perna A, Velluto C, Smakaj A, Bocchi MB, Fumo C, Fresta L, Tamburrelli FC (2021) Correction of a severe coronal malalignment in adult spinal deformity using the "kickstand rod" technique as primary surgery. J Orthop 25:252-258. doi: 10.1016/j.jor.2021.05.028 Makhni MC, Cerpa M, Lin JD, Park PJ, Lenke LG (2018) The “Kickstand Rod” technique for correction of coronal imbalance in patients with adult spinal deformity: theory and technical considerations. Journal of Spine Surgery 4:798-802 Tables Table 1 Variable NCIB (135) CIB (34) p-value Age 70.9 ± 5.0 71.2 ± 5.7 0.751 Female, N(%) 123 (91.1) 29 (85.3) 0.491 Body mass index 22. 8 ± 3.3 23.5 ± 4.4 0.353 ASA-PS 1.9 ± 0.4 2.1 ± 0.3 0.066 T-score -1.6 ± 0.9 -1.7 ± 0.7 0.634 LLIF, N(%) 59 (43.7) 17 (50.0) 0.641 Fusion segment 9.2 ± 2.2 9.9 ± 2.3 0.007* Satellite rod, n(%) 77 (57.0) 19 (55.9) 1.000 NCIB: Non coronal imbalance, CIB: Coronal imbalance, ASA-PS: American Society of anesthesiologists performance status, LLIF: Lateral lumbar interbody fusion, * A significant difference. Table 2 Variable NCIB (135) CIB (34) p-value C7-CSVL (mm) 28.3 ± 29.0 43.9 ± 36.2 0.024* LL (°) 8.2 ± 22.6 14.4 ± 21.2 0.142 TK (°) 22.6 ± 19.0 24.6 ± 18.1 0.589 SS (°) 16.1 ± 12.2 17.9 ± 10.3 0.365 PI (°) 51.5 ± 12.9 54.7 ± 9.8 0.114 PT (°) 35.6 ± 12.7 36.8 ± 10.9 0.593 SVA (mm) 126.5 ± 84.8 139.6 ± 72.0 0.364 Cobb angle (°) 26.2 ± 18.8 41.1 ± 20.4 0.000* NCIB: Non coronal imbalance, CIB: Coronal imbalance, CSVL: central sacral vertical line, LL: lumbar lordosis, TK: thoracic kyphosis, SS: sacral slope, PI: pelvic incidence, PT: pelvic tilt, SVA: sagittal vertical axis. * A significant difference. Table 3 Postoperative 1 year Postoperative 2 year Postoperative 5 year Variable NCIB (135) CIB (34) p-value NCIB (135) CIB (34) p-value NCIB (135) CIB (34) p-value C7-CSVL (mm) 14.4 ± 12.6 39.1 ± 12.9 0.000* 17.2 ± 17.1 37.5 ± 15.9 0.000* 18.1 ± 15.4 41.4 ± 15.6 0.000* LL (°) 41.7 ± 12.3 40.7 ± 14.9 0.74 41.2 ± 12.6 39.8 ± 13.5 0.612 40.3 ± 11.1 38.6 ± 13.4 0.514 TK (°) 41.1 ± 14.0 38.4 ± 13.7 0.31 42.4 ± 14.1 39.4 ± 11.0 0.18 43.7 ± 13.8 41.8 ± 14.1 0.494 SS (°) 27.6 ± 9.8 28.8 ± 7.8 0.456 27.2 ± 8.9 27.1 ± 6.9 0.937 26.8 ± 8.1 26.3 ± 7.6 0.753 PI (°) 52.6 ± 11.8 53.9 ± 9.6 0.484 52.1 ± 11.4 52.8 ± 8.3 0.675 52.1 ± 10.1 55.0 ± 8.7 0.102 PT (°) 25.0 ± 9.8 25.2 ± 7.6 0.913 25.4 ± 9.3 25.4 ± 7.4 0.963 25.7 ± 9.4 28.6 ± 7.8 0.065 C7SVA (mm) 50.0 ± 49.5 50.1 ± 62.1 0.991 60.1 ± 57.1 60.1 ± 63.0 1.000 73.6 ± 53.6 67.3 ± 71.3 0.631 Cobb angle (°) 8.2 ± 6.8 11.3 ± 7.4 0.034 9.0 ± 7.8 11.4 ± 7.6 0.106 9.9 ± 8.2 14.3 ± 10.1 0.024* NCIB: Non coronal imbalance, CIB: Coronal imbalance, CSVL: central sacral vertical line, LL: lumbar lordosis, TK: thoracic kyphosis, SS: sacral slope, PI: pelvic incidence, PT: pelvic tilt, SVA: sagittal vertical axis. * A significant difference. Table 4 Before surgery After 1 year After 2 years After 5 years Variable NCIB (135) CIB (34) p NCIB (135) CIB (34) p NCIB (135) CIB (34) p NCIB (135) CIB (34) p Function 2.6 ± 0.7 2.4 ± 0.6 0.304 3.2 ± 0.8 3.2 ± 0.9 0.769 3.3 ± 0.8 3.1 ± 0.8 0.358 3.2 ± 0.8 3.3 ± 0.7 0.51 Pain 2.9 ± 0.8 3.1 ± 1.1 0.349 3.8 ± 0.7 3.9 ± 0.9 0.825 3.8 ± 0.8 3.9 ± 0.9 0.616 3.8 ± 0.9 4.1 ± 0.8 0.05 Self image 2.0 ± 0.7 1.8 ± 0.6 0.164 3.4 ± 0.8 3.5 ± 0.8 0.731 3.4 ± 0.8 3.3 ± 0.7 0.479 3.2 ± 0.8 3.0 ± 0.7 0.374 Mental health 2.6 ± 0.9 2.5 ± 1.0 0.612 3.4 ± 0.9 3.3 ± 1.1 0.502 3.5 ± 0.8 3.4 ± 0.9 0.788 3.3 ± 0.9 3.3 ± 0.9 0.847 Satisfaction 3.1 ± 0.6 3.0 ± 0.6 0.473 3.6 ± 0.8 3.6 ± 0.6 0.928 3.6 ± 0.9 3.6 ± 0.6 0.935 3.5 ± 0.8 3.5 ± 0.8 1.000 ODI 45±14 42±18 0.381 31±18 30±23 0.869 30±18 30±21 0.971 31 19 27±19 0.289 NCIB: Non coronal imbalance, CIB: Coronal imbalance, ODI: Oswestry disability index. Table 5 NCIB (135) CIB (34) p-value PJK, n(%) 21 (15.6) 10 (29.4) 0.082 PJF, n(%) 8 (5.9) 4 (11.8) 0.263 Rod fracture, n(%) 23 (17.0) 12 (35.3) 0.034* Revision, n(%) 24 (17.8) 12 (35.3) 0.035* NCIB: Non coronal imbalance, CIB: Coronal imbalance, PJK: proximal junctional kyphosis, PJF: proximal junctional failure, * A significant difference. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 25 Dec, 2025 Reviews received at journal 25 Dec, 2025 Reviews received at journal 06 Dec, 2025 Reviews received at journal 05 Dec, 2025 Reviewers agreed at journal 01 Dec, 2025 Reviewers agreed at journal 27 Nov, 2025 Reviewers agreed at journal 25 Nov, 2025 Reviewers invited by journal 25 Nov, 2025 Editor assigned by journal 19 Nov, 2025 Submission checks completed at journal 19 Nov, 2025 First submitted to journal 13 Nov, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8102655","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":551783079,"identity":"3e0e3d72-0a45-4f2c-a195-efe18e0c8a47","order_by":0,"name":"Tomohiro Yamada","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0ElEQVRIiWNgGAWjYJACiQQGCzn74w1ApoEF0VokjBnOHABpkSBSCxAlNtxIgLIJAf723oc3HtRIMDbOfH51w48CCaBIdwJ+G84cN7ZIOCbBzCydU3azB+gwiTNnN+DVYiCRxiaRwCbBxiadk3aDB6jFQCKXGC3/JHh4JM+k3fxDtJbENgkgYD92myhbJM4cY7ZI7JMwMODJYbstYyDBQ9Av/O1tjDd/fLOp38B+/NnNN39s5IBhiF8LEuAxAJPEKgcB9gekqB4Fo2AUjIIRBABGWUD3gGfh/AAAAABJRU5ErkJggg==","orcid":"","institution":"Hamamatsu University School of Medicine","correspondingAuthor":true,"prefix":"","firstName":"Tomohiro","middleName":"","lastName":"Yamada","suffix":""},{"id":551783080,"identity":"0ffd6d5f-c736-45b5-8784-e52cfd61520e","order_by":1,"name":"Yu Yamato","email":"","orcid":"","institution":"Hamamatsu University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Yu","middleName":"","lastName":"Yamato","suffix":""},{"id":551783081,"identity":"9872b9a1-28d2-4103-86e9-b43bb750d095","order_by":2,"name":"Tomohiko Hasegawa","email":"","orcid":"","institution":"JA Shizuoka Koseiren ENSHU hospital","correspondingAuthor":false,"prefix":"","firstName":"Tomohiko","middleName":"","lastName":"Hasegawa","suffix":""},{"id":551783082,"identity":"5d276aad-670d-40ac-b1b8-3396fe69ebb3","order_by":3,"name":"Go Yoshida","email":"","orcid":"","institution":"Hamamatsu University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Go","middleName":"","lastName":"Yoshida","suffix":""},{"id":551783083,"identity":"f10b506f-faa1-41d0-aeb1-801f75d88a73","order_by":4,"name":"Tomohiro Banno","email":"","orcid":"","institution":"Hamamatsu University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Tomohiro","middleName":"","lastName":"Banno","suffix":""},{"id":551783084,"identity":"55e2b23f-5ae2-4f9c-be00-95aed8374693","order_by":5,"name":"Hideyuki Arima","email":"","orcid":"","institution":"Hamamatsu University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Hideyuki","middleName":"","lastName":"Arima","suffix":""},{"id":551783085,"identity":"3486e0ff-3b21-43f4-99c4-f8bbac26ee11","order_by":6,"name":"Shin Oe","email":"","orcid":"","institution":"Hamamatsu University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Shin","middleName":"","lastName":"Oe","suffix":""},{"id":551783088,"identity":"feeb4f64-787d-4e79-94f8-90205e727c9f","order_by":7,"name":"Hiroki Ushirozako","email":"","orcid":"","institution":"Hamamatsu University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Hiroki","middleName":"","lastName":"Ushirozako","suffix":""},{"id":551783091,"identity":"1e79ca5d-a6de-4075-b826-b5115794913f","order_by":8,"name":"Koichiro Ide","email":"","orcid":"","institution":"Hamamatsu University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Koichiro","middleName":"","lastName":"Ide","suffix":""},{"id":551783092,"identity":"07bf3953-d157-4f2e-8ec1-40d32ff95d55","order_by":9,"name":"Yusuke Murakami","email":"","orcid":"","institution":"Ehime University","correspondingAuthor":false,"prefix":"","firstName":"Yusuke","middleName":"","lastName":"Murakami","suffix":""},{"id":551783094,"identity":"df7ed298-9e89-4706-b70b-cec846671eea","order_by":10,"name":"Yukihiro Matsuyama","email":"","orcid":"","institution":"Hamamatsu University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Yukihiro","middleName":"","lastName":"Matsuyama","suffix":""}],"badges":[],"createdAt":"2025-11-13 07:23:20","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8102655/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8102655/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":97128092,"identity":"deb13f9a-c22f-4d7d-a075-b0fca7a8b965","added_by":"auto","created_at":"2025-12-01 08:33:25","extension":"jpg","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":72798,"visible":true,"origin":"","legend":"","description":"","filename":"figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/140fc59520bc8f2ddd40e755.jpg"},{"id":97128097,"identity":"014da0df-36c8-485a-b93a-e62eff3d59ee","added_by":"auto","created_at":"2025-12-01 08:33:25","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":63307,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.docx","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/638d3af05ea91436d3d51878.docx"},{"id":97128093,"identity":"e070a729-b1c0-432b-ada9-1e3e258782f2","added_by":"auto","created_at":"2025-12-01 08:33:25","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":14088,"visible":true,"origin":"","legend":"","description":"","filename":"table1.docx","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/4a666c4162458ed821f67373.docx"},{"id":97142514,"identity":"6ec72d55-133d-4991-bf12-854d318ca4e3","added_by":"auto","created_at":"2025-12-01 10:07:41","extension":"jpg","order_by":3,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":49681,"visible":true,"origin":"","legend":"","description":"","filename":"figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/0979d647cf1d9a9cc194234d.jpg"},{"id":97142926,"identity":"ffb2b537-63a5-4096-8d27-5725a0170d4f","added_by":"auto","created_at":"2025-12-01 10:08:07","extension":"docx","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":15993,"visible":true,"origin":"","legend":"","description":"","filename":"table2.docx","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/975ed7e20dc259c8bf2c19da.docx"},{"id":97128095,"identity":"cdae887b-510e-4c68-b555-1e7746e5446d","added_by":"auto","created_at":"2025-12-01 08:33:25","extension":"jpg","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":55500,"visible":true,"origin":"","legend":"","description":"","filename":"figure3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/27eac2342e1c07a0dc5c1efc.jpg"},{"id":97128098,"identity":"6ff597a3-4fe5-43b5-a7d2-b572abbe4812","added_by":"auto","created_at":"2025-12-01 08:33:25","extension":"docx","order_by":6,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":18067,"visible":true,"origin":"","legend":"","description":"","filename":"table3.docx","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/5e5872ea5d09e86e20eba2a3.docx"},{"id":97142829,"identity":"0755f9f3-54c7-4898-96e1-88f586f6f60d","added_by":"auto","created_at":"2025-12-01 10:07:58","extension":"docx","order_by":7,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":17887,"visible":true,"origin":"","legend":"","description":"","filename":"table4.docx","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/eb8132fb4ba866e64b0667a1.docx"},{"id":97128100,"identity":"ff53aa33-7ca0-4e67-830a-163fad7907b4","added_by":"auto","created_at":"2025-12-01 08:33:25","extension":"docx","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":16210,"visible":true,"origin":"","legend":"","description":"","filename":"table5.docx","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/957818bc09aabab2fca2a5c1.docx"},{"id":97142158,"identity":"cb951bb9-e671-4a9e-9a68-624ee09231c9","added_by":"auto","created_at":"2025-12-01 10:07:23","extension":"json","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":11471,"visible":true,"origin":"","legend":"","description":"","filename":"be6fc8e30f964d7fa5e12cc5263ff410.json","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/8100ffb58c476425a0af5112.json"},{"id":97128104,"identity":"67b2fbeb-1ec9-4e09-9528-908b5b126a19","added_by":"auto","created_at":"2025-12-01 08:33:25","extension":"xml","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":78436,"visible":true,"origin":"","legend":"","description":"","filename":"be6fc8e30f964d7fa5e12cc5263ff4101enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/25c2a739e2561e02f5a315c9.xml"},{"id":97128109,"identity":"90e1d634-f260-403a-8af6-b6d4d0a091b0","added_by":"auto","created_at":"2025-12-01 08:33:26","extension":"jpg","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":72798,"visible":true,"origin":"","legend":"","description":"","filename":"figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/236c2535efaeeef519dbd4ee.jpg"},{"id":97128101,"identity":"4367ed3d-fba4-460f-940b-f7b5de0178e9","added_by":"auto","created_at":"2025-12-01 08:33:25","extension":"jpg","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":49681,"visible":true,"origin":"","legend":"","description":"","filename":"figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/f99f7baa05d3dc80f8f371a7.jpg"},{"id":97128106,"identity":"15d9b9d6-1575-47f3-91e7-94cddf7eb056","added_by":"auto","created_at":"2025-12-01 08:33:26","extension":"jpg","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":55500,"visible":true,"origin":"","legend":"","description":"","filename":"figure3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/5371d53924d9c212402cee53.jpg"},{"id":97128110,"identity":"9bc91472-b743-4801-a8e4-2857b719bd6f","added_by":"auto","created_at":"2025-12-01 08:33:26","extension":"png","order_by":14,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":17897,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefigure1.png","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/69d23146f305b5c08d428171.png"},{"id":97128107,"identity":"9825617d-2fc3-4eff-a0cf-7294ce239fdf","added_by":"auto","created_at":"2025-12-01 08:33:26","extension":"png","order_by":15,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":47335,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefigure2.png","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/651dbd3a381852f21aa28409.png"},{"id":97142173,"identity":"1b20423f-fdab-46cf-9d06-95e95deaa2da","added_by":"auto","created_at":"2025-12-01 10:07:23","extension":"png","order_by":16,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":61838,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefigure3.png","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/6dbb0f72998b6fb3fb1090d1.png"},{"id":97142788,"identity":"b36e549e-d198-4943-9fe6-76625c42d04d","added_by":"auto","created_at":"2025-12-01 10:07:56","extension":"xml","order_by":17,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":75222,"visible":true,"origin":"","legend":"","description":"","filename":"be6fc8e30f964d7fa5e12cc5263ff4101structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/7f83377b0b7b08ae9b84b72c.xml"},{"id":97128111,"identity":"450e9f26-c646-41f6-8d82-38c958ff7d49","added_by":"auto","created_at":"2025-12-01 08:33:26","extension":"html","order_by":18,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":81751,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/bce5d24d36689c2ac6d2f213.html"},{"id":97128091,"identity":"edb61e92-f515-4e95-814d-b588f0668980","added_by":"auto","created_at":"2025-12-01 08:33:25","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":80638,"visible":true,"origin":"","legend":"\u003cp\u003eFlowchart of patient selection. A total of 241 elderly patients (≥ 65 years) who underwent adult spinal deformity (ASD) surgery with pelvic fixation between 2010 and 2020 were reviewed. Among them, 169 patients (70.1%) had a minimum 5-year follow-up and were included in the final analysis. Based on postoperative coronal alignment, patients were divided into those with postoperative coronal imbalance (CIB; \u003cem\u003en\u003c/em\u003e = 34, 20.1%) and those without CIB (\u003cem\u003en\u003c/em\u003e = 135).\u003c/p\u003e","description":"","filename":"figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/a1e2c9d5a1a0ab3379e391a1.jpg"},{"id":97128090,"identity":"0a80e8bf-0d7e-46ff-8a87-ba053819300c","added_by":"auto","created_at":"2025-12-01 08:33:25","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":52088,"visible":true,"origin":"","legend":"\u003cp\u003eBar plot displays mean coronal imbalance (C7CSVL) at four time points: just after surgery, postoperative 1 year (PO1Y), 2 years (PO2Y), and 5 years (PO5Y), with error bars representing standard deviation. While coronal imbalance initially decreased by PO2Y, indicating compensation, a significant increase was observed again at PO5Y.\u003c/p\u003e","description":"","filename":"figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/2c893015d287f9ab24f7dd88.jpg"},{"id":97142850,"identity":"8b58dc9e-1820-47e4-89b1-59dd21388137","added_by":"auto","created_at":"2025-12-01 10:08:00","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":62866,"visible":true,"origin":"","legend":"\u003cp\u003eKaplan-Meier survival curves show rod fracture-free survival over a 5-year follow-up period in patients with and without postoperative coronal imbalance (CIB). The CIB group demonstrated significantly lower survival compared to the non-CIB group. The difference between the groups was statistically significant, as determined by the log-rank test (\u003cem\u003ep\u003c/em\u003e = 0.0069). The hazard ratio for rod fracture in the CIB group compared to the non-CIB group was 2.54, with a 95% confidence interval of 1.26 to 5.14.\u003c/p\u003e","description":"","filename":"figure3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/23294a72c3071c6f29429221.jpg"},{"id":97248454,"identity":"4324c0ff-229d-4382-ae10-00d11439eb4d","added_by":"auto","created_at":"2025-12-02 12:58:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":906078,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8102655/v1/55338eed-6374-4b50-a771-6616eae6fb5c.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003ePostoperative Coronal Imbalance Predicts Late Mechanical Failure and Revision Surgery After Adult Spinal Deformity Correction With Pelvic Fixation: A 5-Year Follow-Up Study in Elderly Patients\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eAdult spinal deformity (ASD) surgery has advanced with the aim of restoring spinopelvic alignment and improving quality of life in elderly patients [1] [2]. While sagittal alignment has been extensively investigated and its restoration is known to correlate with clinical outcomes [3] [4], coronal alignment has received comparatively less attention. Postoperative coronal imbalance (CIB), most commonly defined as a coronal vertical axis (C7CSVL) deviation greater than 3 cm, remains a frequent concern in long fusion surgery for ASD [5].\u003c/p\u003e\u003cp\u003eSeveral studies have reported associations between postoperative CIB and mechanical complications such as rod fracture (RF), proximal junctional kyphosis (PJK), and proximal junctional failure (PJF) [6] [7]. However, these investigations have included heterogeneous populations across a wide age range, variable fusion levels, and inconsistent use of pelvic fixation [8]. Most reports are also limited to short- or mid-term follow-up (typically two years), leaving uncertainty about whether CIB influences long-term outcomes [9], particularly revision surgery [10]. Furthermore, the independent role of CIB in the development of mechanical complications remains unclear, as many prior analyses did not adequately separate coronal malalignment from sagittal malalignment [5] [11]. From a clinical standpoint, clarification of these issues is important. Revision surgery for mechanical complications places a substantial burden on elderly patients, in whom physiological reserve, bone quality, and tolerance for reoperation are limited [7]. Understanding whether postoperative CIB independently increases the risk of mechanical complications and late revision is critical for surgical planning, risk stratification, and long-term patient counseling.\u003c/p\u003e\u003cp\u003eThe present study aimed to evaluate the impact of postoperative CIB on the incidence of mechanical complications and revision surgery in elderly patients undergoing ASD surgery with pelvic fixation. With a minimum follow-up of 5 years, this study specifically investigated whether residual CIB influences long-term revision burden independent of sagittal alignment parameters and whether the effect becomes more evident with extended follow-up. We hypothesized that postoperative CIB would be associated with an increased risk of mechanical complications and revision surgery, particularly during long-term follow-up. In addition, we hypothesized that in patients with rod fracture, the fracture would occur more frequently on the side of the coronal shift, reflecting asymmetric load distribution related to residual imbalance.\u003c/p\u003e"},{"header":"Material and Methods","content":"\u003cp\u003eThis was a retrospective, single-center study. Patients aged\u0026thinsp;\u0026ge;\u0026thinsp;65 years who underwent corrective fusion surgery for adult spinal deformity (ASD) with pelvic fixation between 2010 and 2020 were reviewed. Inclusion criteria were availability of whole-spine standing radiographs at baseline and a minimum follow-up duration of 5 years. Postoperative CIB was defined and classified using the first standing whole-spine radiograph obtained within one week after surgery. Patients with incomplete radiographic data or follow-up \u0026lt;\u0026thinsp;5 years were excluded. The study size was determined by the number of eligible patients available in our institutional database during the study period; no a priori sample size calculation was performed. This study was approved by our local institutional review board (#20\u0026ndash;289), which waived the requirement for informed consent due to the retrospective nature of the study.\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eMechanical complications and revision surgery\u003c/h2\u003e\u003cp\u003eMechanical complications of interest included PJK, PJF, and RF. Revision surgery was defined as surgical intervention for PJF or rod fracture in patients who experienced associated pain or functional disturbance. PJK was defined as showing\u0026thinsp;\u0026gt;\u0026thinsp;20 degrees of kyphosis angle at two levels above the upper instrumented vertebrae [12]. PJF was defined as symptomatic PJK that required surgery. In addition to evaluating overall incidence, we investigated the laterality of rod fracture in relation to the direction of coronal imbalance. For each patient with rod fracture, the fracture side was recorded and compared with the side of the trunk shift measured by C7CSVL\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eSurgical procedure\u003c/h3\u003e\n\u003cp\u003eCorrection of spinal deformity was performed with the goal of restoring sagittal alignment in accordance with each patient\u0026rsquo;s intrinsic pelvic incidence, which dictates the optimal target for lumbar lordosis [13]. Rod selection was a 6.0 mm diameter pure titanium rod in all cases. In all cases requiring pelvic fixation, iliac screws were employed as reliable anchors to provide distal stability. Using these anchors, lumbar lordosis was restored through a cantilever technique, which allowed for controlled correction of sagittal malalignment. Concurrently, coronal deformities were addressed using rod translation and rod rotation maneuvers to achieve three-dimensional realignment. This strategy ensured that both sagittal and coronal parameters were corrected in a manner consistent with the patient\u0026rsquo;s individual spinopelvic morphology, thereby promoting durable mechanical stability and improved clinical outcomes.\u003c/p\u003e\n\u003ch3\u003eIntraoperative strategy for coronal balance\u003c/h3\u003e\n\u003cp\u003eAfter completion of corrective maneuvers, intraoperative long-cassette anteroposterior radiographs including the entire spine and pelvis were obtained with the patient in the prone position. The coronal alignment of the C7 plumb line relative to the central sacral vertical line and the leveling of the pelvis were evaluated on these images. Additional rod contouring, compression\u0026ndash;distraction adjustment were performed as needed to minimize coronal offset before final tightening. This process was applied systematically to all cases to achieve optimal coronal alignment at the time of fixation.\u003c/p\u003e\n\u003ch3\u003eRadiographic assessment and patient reported outcomes\u003c/h3\u003e\n\u003cp\u003ePostoperative CIB was defined as C7CSVL\u0026thinsp;\u0026gt;\u0026thinsp;3 cm in first standing radiograph within postoperative 1 week. Pre- and postoperative sagittal parameters using whole-spine radiographs (anteroposterior and lateral) were collected from patients in the standing position. Lateral radiographs were obtained with the patients gazing horizontally in a natural free-standing posture with their fingers on the clavicles. The following radiograph parameters were assessed: (1) lumbar lordosis (LL), the angle between the upper endplate of the L1 vertebra and the upper endplate of the S1 vertebra; (2) thoracic kyphosis (TK), the angle between the upper endplate of T5 and the lower endplate of T12; (3) sacral slope (SS); (4) pelvic tilt (PT); (5) pelvic incidence (PI); and (6) C7 SVA (the distance between a plum line from the center of the C7 vertebra and the posterior superior center of the sacrum). C7CSVL was defined as the horizontal distance between a vertical plumb line dropped from the center of the C7 vertebral body and the central sacral vertical line. Pre and postoperative patients reported outcomes (PROs), including the Scoliosis Research Society-22 (SRS-22) and Oswestry Disability Index (ODI), were evaluated.\u003c/p\u003e\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003eStatistical analysis\u003c/h2\u003e\u003cp\u003eDescriptive statistics are depicted as means and standard deviations and were calculated for the demographic data. Differences in individual parameters were assessed using unpaired \u003cem\u003et-\u003c/em\u003etest, chi-square test, and Fisher\u0026rsquo;s exact test. Continuous variables were expressed as means\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviations and categorical variables as counts and percentages. Intergroup comparisons (CIB vs. no-CIB) were performed using unpaired \u003cem\u003et\u003c/em\u003e tests, and Fisher\u0026rsquo;s exact tests for categorical variables. For longitudinal analyses of radiographic parameters and patient-reported outcomes (PROs; SRS-22r and ODI), data obtained after revision surgery were excluded because revision procedures can directly influence spinal alignment and symptom scores. Each patient contributed data to the 1-, 2-, and 5-year evaluations only if they had not undergone revision before that time point. Patients who underwent revision remained included in analyses of mechanical complication incidence, survival analysis, and baseline characteristics.\u003c/p\u003e\u003cp\u003eRevision-free survival was assessed using Kaplan\u0026ndash;Meier analysis, and differences between groups were evaluated with the log-rank test. Cox proportional-hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for revision surgery associated with postoperative CIB. All statistical analyses were conducted using SPSS software (version 26.0; IBM Corp., Armonk, NY, USA), and statistical significance was set at \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eAmong 241 patients who underwent adult spinal deformity surgery with pelvic fixation, 169 (70.1%) had a minimum follow-up of 5 years. Of these, 34 patients (20.1%) demonstrated postoperative CIB, and 135 patients (79.9%) did not (Fig.\u0026nbsp;1). Baseline demographic characteristics, including age, sex, and body mass index, did not differ significantly between groups. The mean number of fused levels was significantly higher in the CIB group compared with the no-CIB group (9.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.3 vs 9.2\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2, p\u0026thinsp;=\u0026thinsp;0.007). Preoperative C7CSVL was also greater in the CIB group (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05) (Table\u0026nbsp;1).\u003c/p\u003e\u003cp\u003ePreoperative spinal alignments showed significantly higher in C7CSVL (p\u0026thinsp;=\u0026thinsp;0.024) and Cobb angle in the CIB group (p\u0026thinsp;\u0026lt;\u0026thinsp;0.01) (table 2). Postoperative spinal alignments were comparable between the two groups (table 3). In the CIB group, postoperative C7CSVL was significantly higher compared to in the no-CIB group. Postoperative CIB over time was persistent in the CIB group (Fig.\u0026nbsp;3). PROs, including SRS-22r total score and ODI, improved significantly from baseline in both groups. However, there were no statistically significant differences between the CIB and no-CIB groups at any postoperative time point (table 4).\u003c/p\u003e\n\u003ch3\u003eMechanical complications\u003c/h3\u003e\n\u003cp\u003eMechanical complication rates were greater in the CIB group (Table\u0026nbsp;5). PJK occurred in 10 of 34 patients with CIB (29.4%) and 21 of 135 patients without CIB (15.6%, p\u0026thinsp;=\u0026thinsp;0.082). PJF developed in 4 of 34 patients with CIB (8.9%) and 8 of 135 patients without CIB (5.9%, p\u0026thinsp;=\u0026thinsp;0.263). RF was identified in of 12 patients with CIB (35.3%) and 23 of 135 patients without CIB (17.0%), with a significant difference between groups (p\u0026thinsp;=\u0026thinsp;0.034). Revision surgery, was performed in 12 of 34 patients with CIB (35.3%) and 24 of 135 patients without CIB (17.8%, p\u0026thinsp;=\u0026thinsp;0.035). Kaplan\u0026ndash;Meier analysis demonstrated significantly reduced revision-free survival in the CIB group (log-rank p\u0026thinsp;=\u0026thinsp;0.007). The hazard of revision surgery was higher in patients with CIB compared with those without CIB (HR\u0026thinsp;=\u0026thinsp;2.5, 95% CI 1.26\u0026ndash;5.15). The divergence of survival curves became apparent after 2 years of follow-up, indicating that the increased revision burden in patients with CIB primarily occurred beyond the early postoperative period (Fig.\u0026nbsp;3).\u003c/p\u003e\n\u003ch3\u003eLaterality of Rod Fracture in Relation to Coronal Imbalance\u003c/h3\u003e\n\u003cp\u003eA subanalysis was conducted to examine the relationship between the direction of postoperative coronal imbalance and the side of rod fracture. Among the 36 patients who experienced rod fracture during the follow-up period, 22 cases (61.0%) occurred on the contralateral side to the direction of C7CSVL deviation, 10 cases (27.8%) occurred on the ipsilateral side, and 4 cases (11.1%) involved bilateral fractures. Although the difference did not reach statistical significance (p\u0026thinsp;=\u0026thinsp;0.108), the tendency toward a higher frequency of rod fracture on the contralateral side suggests asymmetric mechanical loading across the construct in the presence of residual coronal imbalance.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this study, we evaluated the impact of CIB on mechanical complications and revision surgery in elderly patients who underwent long fusion surgery with pelvic fixation for ASD surgery. Patients who exhibited postoperative CIB demonstrated significantly higher rates of rod fracture and revision surgery compared with those who achieved coronal balance, whereas the incidences of PJK and PJF were not statistically different. Kaplan\u0026ndash;Meier survival analysis revealed that revision-free survival declined markedly in the CIB group after two years postoperatively, indicating that the detrimental influence of CIB becomes evident in the mid- to long-term period. These findings suggest that even when sagittal alignment parameters such as C7SVA are comparable, residual coronal malalignment independently contributes to increased mechanical stress within the construct, predisposing patients to rod fracture and subsequent revision surgery. The present results underscore the importance of achieving adequate coronal balance at the initial standing position after surgery to prevent delayed mechanical failure in elderly ASD patients undergoing pelvic fixation.\u003c/p\u003e\u003cp\u003ePrevious studies have described the association between postoperative CIB and mechanical complications following ASD surgery [14], yet most included heterogeneous populations and short-term evaluations. Park et al. demonstrated that postoperative coronal malalignment, defined as C7CSVL\u0026thinsp;\u0026gt;\u0026thinsp;3 cm, increased the incidence of revision for rod fracture in long-segment fusions extending to the sacrum [15]. Similarly, Zuckerman et al. reported that patients with coronal malalignment had higher rates of major complications, although reoperation rates were not statistically different [16]. These milestone investigations established the clinical relevance of coronal alignment; however, their study populations were primarily middle-aged, the use of pelvic fixation was inconsistent, and the follow-up period was generally limited to two years. Consequently, the long-term impact of postoperative coronal imbalance and its behavior in elderly patients with uniform pelvic fixation have remained uncertain.\u003c/p\u003e\u003cp\u003eThe present study builds on these earlier findings by focusing specifically on an elderly cohort (\u0026ge;\u0026thinsp;65 years) undergoing ASD correction with pelvic fixation and long-term follow-up of at least five years. This design minimized heterogeneity in distal construct configuration and captured mechanical complications that developed beyond the early postoperative phase. Importantly, the rate of satellite-rod use was comparable between groups, allowing coronal alignment itself to be evaluated independently of construct reinforcement [17], [18]. Despite these modern technical measures, patients with postoperative coronal imbalance exhibited a significantly higher incidence of rod fracture and revision surgery, with a clear divergence in revision-free survival observed after two years. This temporal pattern indicates that the adverse influence of coronal imbalance persists even in stable, multi-rod constructs and becomes more evident over time. Collectively, these findings extend previous knowledge by demonstrating that residual coronal malalignment remains a critical mechanical risk factor in contemporary ASD surgery, particularly in elderly patients whose reduced bone quality and physiological reserve heighten the consequences of late mechanical failure [9].\u003c/p\u003e\u003cp\u003eDespite the higher incidence of mechanical complications and revision surgery in patients with postoperative CIB, PROs, including the SRS-22r and ODI, did not differ significantly between groups. This apparent discrepancy may be partly attributable to the timing of outcome assessment. PROs were collected at predetermined intervals, whereas many revision surgeries occurred beyond two years postoperatively, often between scheduled evaluations. As a result, patients who experienced pain or functional decline preceding revision may not have been captured in the corresponding assessment window, leading to potential underestimation of the true clinical impact of late mechanical failure. Moreover, elderly patients often demonstrate adaptive behavior to progressive imbalance or discomfort, which can attenuate perceived functional decline and diminish sensitivity of questionnaire-based evaluations [19]. Therefore, the absence of a significant difference in PROs should not be interpreted as evidence of equivalent clinical recovery, but rather as a reflection of temporal and reporting bias inherent to long-term follow-up in elderly populations with progressive mechanical complications.\u003c/p\u003e\u003cp\u003ePreoperative coronal alignment and fusion length [18] have been recognized as major risk factors for postoperative coronal imbalance. In the present study, patients who developed postoperative CIB showed greater preoperative C7CSVL and longer fusion constructs compared with those who remained balanced. These findings are consistent with previous reports which identified large preoperative coronal offset and lumbosacral fractional-curve rigidity as key predictors of residual malalignment [16, 20]. Likewise, Lewis et al. emphasized the importance of controlling distal coronal tilt, particularly at L4 and L5, to prevent postoperative trunk shift in long pelvic-fixation constructs. [21] Taken together, both our results and prior evidence suggest that the magnitude of preoperative coronal deviation and the complexity inherent to longer fusion spans increase the risk of residual CIB, underscoring the importance of meticulous preoperative planning and intraoperative coronal leveling to optimize global alignment.\u003c/p\u003e\u003cp\u003eTo our knowledge, this study is the first to analyze the laterality of rod fracture in relation to postoperative coronal imbalance. Among 36 rod fracture cases, fractures occurred more frequently on the contralateral side to the C7CSVL deviation, suggesting that residual coronal malalignment induces asymmetric mechanical loading across the construct. This finding provides clinical evidence supporting the biomechanical concept proposed in prior modeling and technical reports, in which coronal trunk shift generates increased tensile and shear stress on the rod opposite to the direction of deviation, while the ipsilateral rod is primarily subjected to compressive stress [22], [23]. Although previous studies have identified postoperative coronal malalignment as a risk factor for rod fracture and revision surgery, none have quantified side-specific fracture patterns relative to coronal shift direction. The present findings therefore expand current understanding of how residual coronal imbalance contributes not only to the overall risk of mechanical failure but also to its spatial distribution within the construct. Clinically, this insight underscores the need to achieve symmetrical coronal alignment at the time of fixation and to consider targeted reinforcement\u0026mdash;such as additional satellite rods or stiffer rod material\u0026mdash;on the side anticipated to experience greater tensile stress when a minor residual coronal offset cannot be fully corrected.\u003c/p\u003e\u003cp\u003eThis study has several limitations that should be acknowledged. First, it was conducted at a single institution, which may limit the generalizability of the findings due to institutional differences in surgical strategy, implant selection, and postoperative management. Second, although the follow-up rate of 70.1% at 5 years was acceptable for a long-term surgical cohort, loss to follow-up may have introduced selection bias. Third, the retrospective design inherently limits causal inference, and unmeasured confounders such as subtle differences in bone quality, muscle mass, or rod contouring technique may have influenced outcomes. Despite these limitations, the uniform surgical indication, consistent use of pelvic fixation, and extended 5-year follow-up strengthen the reliability of the present findings.\u003c/p\u003e\u003cp\u003eIn conclusion, postoperative CIB as an independent risk factor for long-term mechanical failure and revision surgery in elderly patients undergoing ASD correction with pelvic fixation. Although early postoperative outcomes were comparable between groups, divergence in revision-free survival emerged beyond two years, indicating that the adverse effects of residual coronal malalignment manifest primarily in the mid- to late-term period. A novel subanalysis further revealed that rod fractures occurred predominantly on the contralateral side to the direction of coronal shift, providing clinical validation of asymmetric mechanical loading across the construct. Together, these findings demonstrate that even subtle postoperative coronal imbalance can impose sustained, asymmetric stress on spinal instrumentation, predisposing to late rod fracture and the need for revision. Achieving symmetrical coronal alignment at the time of fixation and considering targeted reinforcement on the tension side may therefore be essential strategies to improve long-term construct durability and reduce revision burden in elderly patients undergoing extensive spinal deformity correction.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eTomohiro Yamada wrote the main manuscript text and prepared all figures ant table. All authors collected data and reviewed the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eMcDowell M, Tempel Z, Gandhoke G, Khattar N, Hamilton D, Kanter A, Okonkwo D (2017) Evolution of Sagittal Imbalance Following Corrective Surgery for Sagittal Plane Deformity. Neurosurgery 81:129. doi: 10.1093/neuros/nyx145\u003c/li\u003e\n\u003cli\u003eLee C, Park J-S, Nam Y, Choi Y-T, Park S (2020) Long-term benefits of appropriately corrected sagittal alignment in reconstructive surgery for adult spinal deformity: evaluation of clinical outcomes and mechanical failures. Journal of neurosurgery Spine:1-9. doi: 10.3171/2020.7.SPINE201108\u003c/li\u003e\n\u003cli\u003eGreenberg J, Whiting B, Martinez O, Butt B, Badhiwala J, Clifton W (2023) Age-Adjusted Alignment Goals in Adult Spinal Deformity Surgery. Seminars in Spine Surgery. doi: 10.1016/j.semss.2023.101027\u003c/li\u003e\n\u003cli\u003eYe J-C, Yin T-C, Gupta S, Farooqi A, Wan W, Yilgor C, Sides B, Gupta M (2022) Use of the Global Alignment and Proportion score to predict postoperative health-related quality of life in adult spinal deformity surgery. Journal of neurosurgery Spine:1-8. doi: 10.3171/2022.9.spine22809\u003c/li\u003e\n\u003cli\u003eBarile F, Ruffilli A, Paolucci A, Viroli G, Manzetti M, Traversari M, Ialuna M, Faldini C (2023) Risk factors for postoperative coronal imbalance after surgical correction of adult spinal deformities: a systematic review with pooled analysis. Journal of neurosurgery Spine:1-15. doi: 10.3171/2023.1.SPINE22669\u003c/li\u003e\n\u003cli\u003eTanaka N, Ebata S, Oda K, Oba H, Haro H, Ohba T (2020) Predictors and Clinical Importance of Postoperative Coronal Malalignment After Surgery to Correct Adult Spinal Deformity. Clinical Spine Surgery 33. doi: 10.1097/BSD.0000000000000947\u003c/li\u003e\n\u003cli\u003eBuell T, Smith J, Shaffrey C, Kim H-J, Klineberg E, Lafage V, Lafage R, Protopsaltis T, Passias P, Mundis G, Eastlack R, Deviren V, Kelly M, Daniels A, Gum J, Soroceanu A, Hamilton D, Gupta M, Burton D, Hostin R, Kebaish K, Hart R, Schwab F, Bess S, Ames C (2020) Multicenter assessment of surgical outcomes in adult spinal deformity patients with severe global coronal malalignment: determination of target coronal realignment threshold. Journal of neurosurgery Spine:1-14. doi: 10.3171/2020.7.SPINE20606\u003c/li\u003e\n\u003cli\u003ePloumis A, Simpson A, Cha T, Herzog J, Wood K (2015) Coronal Spinal Balance in Adult Spine Deformity Patients With Long Spinal Fusions: A Minimum 2- to 5-Year Follow-up Study. Journal of Spinal Disorders and Techniques 28:341. doi: 10.1097/BSD.0b013e3182aab2ff\u003c/li\u003e\n\u003cli\u003eBae J (2021) Commentary on \u0026ldquo;Characteristics and Risk Factors of Rod Fracture Following Adult Spinal Deformity Surgery: A Systematic Review and Meta-Analysis\u0026rdquo;. Neurospine 18:455-456. doi: 10.14245/ns.2142816.408\u003c/li\u003e\n\u003cli\u003eIshihara M, Taniguchi S, Ono N, Adachi T, Tani Y, Paku M, Kawashima K, Ando M, Saito T (2023) New Effective Intraoperative Techniques for the Prevention of Coronal Imbalance after Circumferential Minimally Invasive Correction Surgery for Adult Spinal Deformity. Journal of Clinical Medicine 12. doi: 10.3390/jcm12175670\u003c/li\u003e\n\u003cli\u003eRuffilli A, Barile F, Paolucci A, Manzetti M, Viroli G, Ialuna M, Vita F, Cerasoli T, Faldini C (2023) Independent Risk Factors of Postoperative Coronal Imbalance after Adult Spinal Deformity Surgery. Journal of Clinical Medicine 12. doi: 10.3390/jcm12103559\u003c/li\u003e\n\u003cli\u003eBridwell KH, Lenke LG, Cho SK, Pahys JM, Zebala LP, Dorward IG, Cho W, Baldus C, Hill BW, Kang MM (2013) Proximal junctional kyphosis in primary adult deformity surgery: evaluation of 20 degrees as a critical angle. Neurosurgery 72:899-906\u003c/li\u003e\n\u003cli\u003eYamato Y, Hasegawa T, Kobayashi S, Yasuda T, Togawa D, Arima H, Oe S, Iida T, Matsumura A, Hosogane N, Matsumoto M, Matsuyama Y (2016) Calculation of the Target Lumbar Lordosis Angle for Restoring an Optimal Pelvic Tilt in Elderly Patients With Adult Spinal Deformity. Spine (Phila Pa 1976) 41:E211-217. doi: 10.1097/brs.0000000000001209\u003c/li\u003e\n\u003cli\u003eBarone G, Giudici F, Martinelli N, Ravier D, Muzzi S, Minoia L, Zagra A, Scaramuzzo L (2021) Mechanical Complications in Adult Spine Deformity Surgery: Retrospective Evaluation of Incidence, Clinical Impact and Risk Factors in a Single-Center Large Series. J Clin Med 10. doi: 10.3390/jcm10091811\u003c/li\u003e\n\u003cli\u003ePark JS, Kang DH, Park SJ, Lee CS, Kim HJ (2025) Influence of postoperative coronal malalignment following long-instrumented fusion in patients with adult spinal deformity: evaluation of clinical outcomes and mechanical complications. Spine J. doi: 10.1016/j.spinee.2025.05.010\u003c/li\u003e\n\u003cli\u003eZuckerman SL, Lai CS, Shen Y, Lee NJ, Kerolus MG, Ha AS, Buchanan IA, Leung E, Cerpa M, Lehman RA, Lenke LG (2023) Postoperative coronal malalignment after adult spinal deformity surgery: incidence, risk factors, and impact on 2-year outcomes. Spine Deform 11:187-196. doi: 10.1007/s43390-022-00583-9\u003c/li\u003e\n\u003cli\u003eYamato Y, Hasegawa T, Yoshida G, Banno T, Oe S, Arima H, Mihara Y, Ushirozako H, Yamada T, Watanabe Y, Ide K, Nakai K, Kurosu K, Matsuyama Y (2022) Revision Surgery for a Rod Fracture with Multirod Constructs Using a Posterior-Only Approach Following Surgery for Adult Spinal Deformity. Asian Spine Journal 16:740-748. doi: 10.31616/asj.2021.0244\u003c/li\u003e\n\u003cli\u003eRabinovich E, Buell T, Wang T, Shaffrey C, Smith J (2021) Reduced occurrence of primary rod fracture after adult spinal deformity surgery with accessory supplemental rods: retrospective analysis of 114 patients with minimum 2-year follow-up. Journal of neurosurgery Spine:1-12. doi: 10.3171/2020.12.spine201527\u003c/li\u003e\n\u003cli\u003eSuijker J, Buurman B, Van Rijn M, Van Dalen M, Ter Riet G, Van Geloven N, De Haan R, Van Charante M, De Rooij S (2014) A simple validated questionnaire predicted functional decline in community-dwelling older persons: prospective cohort studies. Journal of clinical epidemiology 67 10:1121-1130. doi: 10.1016/j.jclinepi.2014.05.014\u003c/li\u003e\n\u003cli\u003eRuffilli A, Barile F, Paolucci A, Manzetti M, Viroli G, Ialuna M, Vita F, Cerasoli T, Faldini C (2023) Independent Risk Factors of Postoperative Coronal Imbalance after Adult Spinal Deformity Surgery. J Clin Med 12. doi: 10.3390/jcm12103559\u003c/li\u003e\n\u003cli\u003eLewis SJ, Keshen SG, Kato S, Dear TE, Gazendam AM (2018) Risk Factors for Postoperative Coronal Balance in Adult Spinal Deformity Surgery. Global Spine J 8:690-697. doi: 10.1177/2192568218764904\u003c/li\u003e\n\u003cli\u003eProietti L, Perna A, Velluto C, Smakaj A, Bocchi MB, Fumo C, Fresta L, Tamburrelli FC (2021) Correction of a severe coronal malalignment in adult spinal deformity using the \u0026quot;kickstand rod\u0026quot; technique as primary surgery. J Orthop 25:252-258. doi: 10.1016/j.jor.2021.05.028\u003c/li\u003e\n\u003cli\u003eMakhni MC, Cerpa M, Lin JD, Park PJ, Lenke LG (2018) The \u0026ldquo;Kickstand Rod\u0026rdquo; technique for correction of coronal imbalance in patients with adult spinal deformity: theory and technical considerations. Journal of Spine Surgery 4:798-802\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 31px;\"\u003e\n \u003cp\u003eVariable\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003eNCIB (135)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003eCIB (34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003ep-value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 31px;\"\u003e\n \u003cp\u003eAge\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e70.9 \u0026plusmn; 5.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e71.2 \u0026plusmn; 5.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e0.751\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 31px;\"\u003e\n \u003cp\u003eFemale, N(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e123 (91.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e29 (85.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e0.491\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 31px;\"\u003e\n \u003cp\u003eBody mass index\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e22. 8 \u0026plusmn; 3.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e23.5 \u0026plusmn; 4.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e0.353\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 31px;\"\u003e\n \u003cp\u003eASA-PS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e1.9 \u0026plusmn; 0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e2.1 \u0026plusmn; 0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e0.066\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 31px;\"\u003e\n \u003cp\u003eT-score\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e-1.6 \u0026plusmn; 0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e-1.7 \u0026plusmn; 0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e0.634\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 31px;\"\u003e\n \u003cp\u003eLLIF, N(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e59 (43.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e17 (50.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e0.641\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 31px;\"\u003e\n \u003cp\u003eFusion segment\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e9.2 \u0026plusmn; 2.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e9.9 \u0026plusmn; 2.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e0.007*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 31px;\"\u003e\n \u003cp\u003eSatellite rod, n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e77 (57.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 24px;\"\u003e\n \u003cp\u003e19 (55.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 19px;\"\u003e\n \u003cp\u003e1.000\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 100px;\"\u003e\n \u003cp\u003eNCIB: Non coronal imbalance, CIB: Coronal imbalance, ASA-PS: American Society of anesthesiologists performance status,\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eLLIF: Lateral lumbar interbody fusion, * A significant difference.\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;Table 2\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eVariable\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eNCIB (135)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eCIB (34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003ep-value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eC7-CSVL (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e28.3 \u0026plusmn; 29.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e43.9 \u0026plusmn; 36.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.024*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eLL (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e8.2 \u0026plusmn; 22.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e14.4 \u0026plusmn; 21.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.142\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eTK (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e22.6 \u0026plusmn; 19.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e24.6 \u0026plusmn; 18.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.589\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eSS (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e16.1 \u0026plusmn; 12.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e17.9 \u0026plusmn; 10.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.365\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003ePI (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e51.5 \u0026plusmn; 12.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e54.7 \u0026plusmn; 9.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.114\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003ePT (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e35.6 \u0026plusmn; 12.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e36.8 \u0026plusmn; 10.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.593\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eSVA (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e126.5 \u0026plusmn; 84.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e139.6 \u0026plusmn; 72.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.364\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eCobb angle (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e26.2 \u0026plusmn; 18.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e41.1 \u0026plusmn; 20.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e0.000*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" rowspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003eNCIB: Non coronal imbalance, CIB: Coronal imbalance, CSVL: central sacral vertical line, LL: lumbar lordosis, TK: thoracic kyphosis,\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eSS: sacral slope, PI: pelvic incidence, PT: pelvic tilt,\u003cbr\u003e\u0026nbsp;SVA: sagittal vertical axis. * A significant difference.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"48\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;Table 3\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 12px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"bottom\" style=\"width: 29px;\"\u003e\n \u003cp\u003ePostoperative 1 year\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"bottom\" style=\"width: 29px;\"\u003e\n \u003cp\u003ePostoperative 2 year\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"bottom\" style=\"width: 29px;\"\u003e\n \u003cp\u003ePostoperative 5 year\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003eVariable\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003eNCIB (135)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003eCIB (34)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003ep-value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003eNCIB (135)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003eCIB (34)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003ep-value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003eNCIB (135)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003eCIB (34)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003ep-value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003eC7-CSVL (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e14.4 \u0026plusmn; 12.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e39.1 \u0026plusmn;\u0026nbsp;12.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.000*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e17.2 \u0026plusmn; 17.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e37.5 \u0026plusmn; 15.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.000*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e18.1 \u0026plusmn; 15.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e41.4 \u0026plusmn;\u0026nbsp;15.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.000*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003eLL (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e41.7 \u0026plusmn; 12.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e40.7 \u0026plusmn; 14.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e41.2 \u0026plusmn; 12.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e39.8 \u0026plusmn; 13.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.612\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e40.3 \u0026plusmn; 11.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e38.6 \u0026plusmn; 13.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.514\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003eTK (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e41.1 \u0026plusmn; 14.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e38.4 \u0026plusmn; 13.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e42.4 \u0026plusmn; 14.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e39.4 \u0026plusmn; 11.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e43.7 \u0026plusmn; 13.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e41.8 \u0026plusmn; 14.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.494\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003eSS (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e27.6 \u0026plusmn; 9.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e28.8 \u0026plusmn; 7.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.456\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e27.2 \u0026plusmn; 8.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e27.1 \u0026plusmn; 6.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.937\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e26.8 \u0026plusmn; 8.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e26.3 \u0026plusmn; 7.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.753\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003ePI (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e52.6 \u0026plusmn; 11.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e53.9 \u0026plusmn; 9.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.484\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e52.1 \u0026plusmn; 11.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e52.8 \u0026plusmn; 8.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.675\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e52.1 \u0026plusmn; 10.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e55.0 \u0026plusmn; 8.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.102\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003ePT (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e25.0 \u0026plusmn; 9.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e25.2 \u0026plusmn; 7.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.913\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e25.4 \u0026plusmn; 9.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e25.4 \u0026plusmn; 7.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.963\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e25.7 \u0026plusmn; 9.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e28.6 \u0026plusmn; 7.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.065\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003eC7SVA (mm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e50.0 \u0026plusmn; 49.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e50.1 \u0026plusmn; 62.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.991\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e60.1 \u0026plusmn; 57.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e60.1 \u0026plusmn; 63.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e1.000\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e73.6 \u0026plusmn; 53.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e67.3 \u0026plusmn; 71.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.631\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 12px;\"\u003e\n \u003cp\u003eCobb angle (\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e8.2 \u0026plusmn; 6.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e11.3 \u0026plusmn; 7.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.034\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e9.0 \u0026plusmn; 7.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e11.4 \u0026plusmn; 7.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.106\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e9.9 \u0026plusmn; 8.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 11px;\"\u003e\n \u003cp\u003e14.3 \u0026plusmn; 10.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6px;\"\u003e\n \u003cp\u003e0.024*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"10\" rowspan=\"2\" valign=\"top\" style=\"width: 100px;\"\u003e\n \u003cp\u003eNCIB: Non coronal imbalance, CIB: Coronal imbalance, CSVL: central sacral vertical line, LL: lumbar lordosis, TK: thoracic kyphosis,\u0026nbsp;\u003c/p\u003e\n \u003cp\u003eSS: sacral slope, PI: pelvic incidence, PT: pelvic tilt, SVA: sagittal vertical axis. * A significant difference.\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"48\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;Table 4\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" align=\"left\" width=\"1059\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 125px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" style=\"width: 233px;\"\u003e\n \u003cp\u003eBefore surgery\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" style=\"width: 233px;\"\u003e\n \u003cp\u003eAfter 1 year\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" style=\"width: 233px;\"\u003e\n \u003cp\u003eAfter 2 years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" style=\"width: 233px;\"\u003e\n \u003cp\u003eAfter 5 years\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 125px;\"\u003e\n \u003cp\u003eVariable\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003eNCIB (135)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003eCIB (34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003eNCIB (135)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003eCIB (34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003eNCIB (135)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003eCIB (34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003eNCIB (135)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003eCIB (34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 125px;\"\u003e\n \u003cp\u003eFunction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e2.6 \u0026plusmn; 0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e2.4 \u0026plusmn; 0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.304\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.2 \u0026plusmn; 0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.2 \u0026plusmn; 0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.769\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.3 \u0026plusmn; 0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.1 \u0026plusmn; 0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.358\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.2 \u0026plusmn; 0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.3 \u0026plusmn; 0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.51\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 125px;\"\u003e\n \u003cp\u003ePain\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e2.9 \u0026plusmn; 0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.1 \u0026plusmn; 1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.349\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.8 \u0026plusmn; 0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.9 \u0026plusmn; 0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.825\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.8 \u0026plusmn; 0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.9 \u0026plusmn; 0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.616\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.8 \u0026plusmn; 0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e4.1 \u0026plusmn; 0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 125px;\"\u003e\n \u003cp\u003eSelf image\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e2.0 \u0026plusmn; 0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e1.8 \u0026plusmn; 0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.164\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.4 \u0026plusmn; 0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.5 \u0026plusmn; 0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.731\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.4 \u0026plusmn; 0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.3 \u0026plusmn; 0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.479\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.2 \u0026plusmn; 0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.0 \u0026plusmn; 0.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.374\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 125px;\"\u003e\n \u003cp\u003eMental health\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e2.6 \u0026plusmn; 0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e2.5 \u0026plusmn; 1.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.612\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.4 \u0026plusmn; 0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.3 \u0026plusmn; 1.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.502\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.5 \u0026plusmn; 0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.4 \u0026plusmn; 0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.788\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.3 \u0026plusmn; 0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.3 \u0026plusmn; 0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.847\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 125px;\"\u003e\n \u003cp\u003eSatisfaction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.1 \u0026plusmn; 0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.0 \u0026plusmn; 0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.473\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.6 \u0026plusmn; 0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.6 \u0026plusmn; 0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.928\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.6 \u0026plusmn; 0.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.6 \u0026plusmn; 0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.935\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.5 \u0026plusmn; 0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e3.5 \u0026plusmn; 0.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e1.000\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 125px;\"\u003e\n \u003cp\u003eODI\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e45\u0026plusmn;14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e42\u0026plusmn;18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.381\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e31\u0026plusmn;18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e30\u0026plusmn;23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.869\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e30\u0026plusmn;18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e30\u0026plusmn;21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.971\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e31 19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 92px;\"\u003e\n \u003cp\u003e27\u0026plusmn;19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 50px;\"\u003e\n \u003cp\u003e0.289\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"13\" style=\"width: 1059px;\"\u003e\n \u003cp\u003eNCIB: Non coronal imbalance, CIB: Coronal imbalance, ODI: Oswestry disability index.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;Table\u0026nbsp; 5\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 28px;\"\u003e\n \u003cp\u003e \u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 26px;\"\u003e\n \u003cp\u003eNCIB (135)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 26px;\"\u003e\n \u003cp\u003eCIB (34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003ep-value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 28px;\"\u003e\n \u003cp\u003ePJK, n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 26px;\"\u003e\n \u003cp\u003e21 (15.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 26px;\"\u003e\n \u003cp\u003e10 (29.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.082\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 28px;\"\u003e\n \u003cp\u003ePJF, n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 26px;\"\u003e\n \u003cp\u003e8 (5.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 26px;\"\u003e\n \u003cp\u003e4 (11.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.263\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 28px;\"\u003e\n \u003cp\u003eRod fracture, n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 26px;\"\u003e\n \u003cp\u003e23 (17.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 26px;\"\u003e\n \u003cp\u003e12 (35.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.034*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 28px;\"\u003e\n \u003cp\u003eRevision, n(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 26px;\"\u003e\n \u003cp\u003e24 (17.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 26px;\"\u003e\n \u003cp\u003e12 (35.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 17px;\"\u003e\n \u003cp\u003e0.035*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" rowspan=\"2\" valign=\"top\" style=\"width: 100px;\"\u003e\n \u003cp\u003eNCIB: Non coronal imbalance, CIB: Coronal imbalance, PJK: proximal junctional kyphosis, PJF: proximal junctional failure,\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e* A significant difference.\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd height=\"48\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd height=\"25\" style=\"width: 0px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"european-spine-journal","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"esjo","sideBox":"Learn more about [European Spine Journal](http://link.springer.com/journal/586)","snPcode":"586","submissionUrl":"https://submission.springernature.com/new-submission/586/3","title":"European Spine Journal","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Coronal imbalance, Rod fracture, Mechanical complications, Adult spinal deformity surgery","lastPublishedDoi":"10.21203/rs.3.rs-8102655/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8102655/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePostoperative coronal imbalance (CIB) is a persistent concern following adult spinal deformity (ASD) surgery. This study aimed to determine whether postoperative CIB independently increases the risk of mechanical complications and revision surgery, and to investigate whether the side of rod fracture correlates with the direction of coronal shift.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe retrospectively reviewed 241 patients aged ≥ 65 years who underwent long-segment ASD correction with pelvic fixation between 2010 and 2020. A total of 169 patients (70.1%) completed a minimum 5-year follow-up. Postoperative CIB was defined as C7CSVL \u0026gt; 3 cm. Mechanical complications included proximal junctional kyphosis (PJK), proximal junctional failure (PJF), and rod fracture. Revision surgery was recorded when reoperation was required for painful PJF or rod fracture. Survival analysis was performed using Kaplan–Meier and Cox proportional-hazard models.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThirty-four patients (20.1%) exhibited postoperative CIB. Compared with patients without CIB, these patients had greater preoperative coronal deviation (p \u0026lt; 0.001) and longer fusion constructs (9.9 ± 2.3 vs 9.2 ± 2.2 levels; p = 0.007), whereas sagittal vertical axis was comparable (p = 0.876). The incidence of rod fracture (35.3% vs 17.0%; p = 0.034) and revision surgery (35.3% vs 17.8%; p = 0.035) was significantly higher in the CIB group. Kaplan–Meier analysis showed reduced 5-year revision-free survival (HR = 2.0; 95% CI 1.0–4.0; log-rank p = 0.046), with divergence of survival curves evident after 2 years. Rod fractures occurred more frequently on the contralateral side to the direction of coronal shift (61.0%).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePostoperative coronal imbalance is an independent predictor of late mechanical failure and revision after ASD correction with pelvic fixation in elderly patients. The novel association between coronal shift direction and rod-fracture laterality provides clinical validation of asymmetric mechanical loading, underscoring the importance of precise coronal alignment and side-specific reinforcement to improve long-term construct durability.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLevel of Evidence: Ⅲ\u003c/strong\u003e\u003c/p\u003e","manuscriptTitle":"Postoperative Coronal Imbalance Predicts Late Mechanical Failure and Revision Surgery After Adult Spinal Deformity Correction With Pelvic Fixation: A 5-Year Follow-Up Study in Elderly Patients","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-01 08:33:21","doi":"10.21203/rs.3.rs-8102655/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-25T10:39:12+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-25T09:31:18+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-07T04:12:25+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-06T01:30:38+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"11099492498735655647754918473595362271","date":"2025-12-02T00:14:10+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"285151307404906180464333653790211977917","date":"2025-11-27T13:19:38+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"130678427760672018432966614014147162052","date":"2025-11-25T09:33:56+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-11-25T09:28:07+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-20T02:24:54+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-11-20T02:24:26+00:00","index":"","fulltext":""},{"type":"submitted","content":"European Spine Journal","date":"2025-11-13T07:09:46+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"european-spine-journal","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"esjo","sideBox":"Learn more about [European Spine Journal](http://link.springer.com/journal/586)","snPcode":"586","submissionUrl":"https://submission.springernature.com/new-submission/586/3","title":"European Spine Journal","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"971dee05-41c2-4f3b-b40d-2a2b1fd0b00f","owner":[],"postedDate":"December 1st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-03-24T16:53:25+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-01 08:33:21","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8102655","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8102655","identity":"rs-8102655","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}