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Purpose: To investigate the age-specific normative values of whole-body sagittal alignment (WBSA) including global balance parameters in healthy adults and to clarify the correlations among parameters based on the data from three international multicenter. Methods: Three hundred and seventeen healthy subjects (range: 20–84 y.o., mean: 43.8 ± 14.7 y.o.) were included and underwent whole-body biplanar X-ray imaging system. Spinopelvic parameters and knee flexion (KF), the center of acoustic meatus (CAM)-hip axis (HA), and C2 dentiform apophyse (OD)-HA, the cranial center (Cr)-HA were evaluated radiologically. Sub-analysis for correlation analysis between age and parameters and among parameters was performed to investigate age-specific change and compensatory mechanisms. Results: For age-related change, C2-7 angle (r = .326 for male/.355 for female), KF (r = .427/.429), and SVA (r = .234/.507) increased with age in both male and female group. For global parameters related to the center of the gravity, correlations with age were not significant (r = .120/.161 for OD-HA, r = .163/.275 for Cr-HA, r = .149/.262 for CAM-HA). Knee flexion (KF) has correlation with global parameters (i.e., SVA, OD-HA, Cr-HA, CAM-HA) and does not have correlations with local spinopelvic alignment. Conclusion: While several local alignment changes with age were found, changes in global parameters related to the center of gravity were kept relatively mild by the chain of compensation mechanisms including the lower limbs. We showed the normative values for a comprehensive WBSA in standing posture from large international healthy subjects’ database.

Purpose: Spinal osteotomies performed to treat fixed spinal deformities are technically demanding and associated with a high complications rate. The main purpose of this study was to analyze complications and their risk factors in spinal osteotomies performed for fixed sagittal imbalance from multiple etiologies. Methods: The study consisted of a blinded retrospective analysis of prospectively collected data from a large multicentre cohort of patients who underwent 3-columns (3C) spinal osteotomy, between january 2010 and january 2017. Clinical and radiological datas were compared pre and post operatively. Complications and their risks factors were analyzed.Results: Two hundred eighty-six 3C osteotomies were performed in 273 patients. At 1year follow-up, both clinical (VAS pain, ODI and SRS-22 scores) and radiological (SVA, SSA, loss of lordosis and pelvic version) parameters were significantly improved (p were assessed as risk factors for overall complication (p (p=0.02).Conclusion: Spinal 3C osteotomies were efficient to improve both clinical and radiological parameters despite high rates of complication. Efforts should be made to reduce operative time which appears to be the strongest predictive risk factor for complication.

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a chronic relapsing disease of unknown aetiology. The diagnosis of this disease is still very complicated. The treatment is medical but, in some cases, a surgical decompression might be required. In rare cases it develops a radicular hypertrophy that can cause a cervical myelopathy; this pathology should be put in differential diagnosis with neurofibromatosis 1 and CharcotMarie-Tooth (CMT) syndromes. The cases of CIDP cervical myelopathy reported in the literature are rare and even more rarely a surgical decompression was described. Here we report a first and unique case of CIDP cervical myelopathy treated with an open-door laminoplasty technique with 10-year postoperative follow-up (FU). The surgical decompression revealed to be effective in stopping the progression of myelopathy without destabilizing the spine. The patient that before surgery presented a severe tetraparesis could return to walk and gain back his self-care autonomy. At 10-year FU he did not complain of neck pain and did not develop a cervical kyphosis. In case of cervical myelopathy caused by radicular hypertrophy, CIDP should be kept in mind in the differential diagnosis and an open-door laminoplasty is indicated to stop myelopathy progression.

Purpose Prospective pre-operative and post-operative comparative analysis of radiographic spino-pelvic parameters between sitting versus standing positions of patients with LS fusion, to detect adaptation mechanisms around fused spinal segments. Methods Sixteen patients aged 53.9 ± 15.9 who underwent LS fusion between L3 and S1 were extracted from the database of an ongoing prospective study. Different spino-pelvic parameters were evaluated on full spine X-rays, standing, then sitting straight. Parameters were compared pre-operative versus post-operative, and on standing versus sitting X-rays. Results Preliminary results revealed a significantly greater pre-operative pelvic tilt (PT) in sitting than standing posture, (p = 0.020) but not in post-operative (p = 0.087). After surgery, PT was lower in sitting compared to pre-operative (p = 0.034) but not in standing (p = 0.245). L4–S1 lordosis was lower in sitting than standing in pre-operative (p = 0.014) and post-operative (p = 0.021). Surgery decreased segmental lordosis above the fusion (PSL, proximal sagittal lordosis) in sitting (p = 0.039) but not in standing (p = 0.193). No significant differences in thoracic kyphosis (TK) were observed. Fusions down to L5 versus S1 showed no significant differences for PT and PSL, neither in sitting versus standing, nor pre-operative versus post-operative. Conclusion Before fusion, compared to standing, PT increases in sitting straight posture (pelvic retroversion), and the lumbar spine adapts by decreasing its lordosis, mainly at L4–S1. After fusion, the segments adjacent to the instrumented section, adapt in flexion at lumbosacral and thoracolumbar junctions, i.e. just below and above (PSL). This might have mechanical implications for the occurrence of adjacent segment disease.

The purpose of this study was to investigate the affecting factors on pelvic incidence (PI) and to test the hypothesis that PI changes even after skeletal maturity probably due to hypermobility of the sacroiliac joint using a large international multi-center database.A prospective and cross-sectional healthy adult volunteers, ages 18-80 years, across 5 countries were used. Radiographic measurements included standard whole body alignment parameters. Bivariate regression analyses between PI versus demographics and spino-pelvic anatomical parameters were performed. An effect of sex on pelvic anatomical parameters was also investigated. Multivariate logistic regression with a forward stepwise procedure was performed to identify the contributing factors to PI, and an appropriate model was obtained.PI showed a significant positive correlation with age in pooled data. Divided by sex, however, there was no correlation in men, but women showed a significant higher correlation coefficient. Pelvic thickness (PTh) had a significant negative correlation with age in pooled data. Divided by sex, no correlation was found in men, but there was a significant correlation in women with higher correlation coefficient. The stepwise multivariate analysis for the factors on PI identified four significant factors: age, sex, ethnicity, and PTh.PTh, sex, ethnicity, and age affected PI. There was a positive correlation between PI and age. The tendency was more significant in woman than in man. The results support the hypothesis that PI increases with aging, but the change seems to be small and needs to be verified in a longitudinal evaluation.

Resume Introduction La necessite d’une arthrodese associee a une decompression chez les patients ayant un canal lombaire etroit reste conversee. Le but de cette etude est de montrer qu’une decompression isolee avait un resultat equivalent a une decompression associee a une arthrodese chez un patient ayant un equilibre sagittal global conserve. Materiel et methodes Une cohorte retrospective et monocentrique de 110 patients operes d’un canal lombaire etroit sur un niveau a ete divisee en deux groupes equivalents en fonction du traitement : decompression isolee ou fusion-decompression. Les patients inclus avaient un ODHA (angle odontoide-axe des hanches et ligne verticale) normal (−5°a + 2°) et ne presentaient pas de spondylolisthesis ni de deformation frontale. Nous avons compare les scores cliniques et les parametres pelvirachidiens en preoperatoire et a un an. Nous avons evalue le MCID (Minimal Clinically Important Difference) correspondant a une difference d’ODI (Owestry disability index) de 12,8 points. Dans chaque groupe, une analyse en fonction du MCID a ete realisee. Resultats Une augmentation significative des scores cliniques dans chaque groupe a ete mise en evidence. Les 2 groupes ont 77 % de diminution de l’ODI > 12,8 points sans difference significative entre les 2 groupes. Enfin, l’analyse en fonction du MCID montre que les patients avec un mauvais resultat clinique a 1 an dans le groupe decompression isolee etaient plus lombalgiques alors qu’ils etaient plus radiculaires dans le groupe decompression-fusion. Conclusion La fusion decompression n’a pas montre de superiorite a un an sur les resultats cliniques et radiologiques en comparaison a la decompression isolee pour la prise en charge d’un canal lombaire etroit monosegmentaire chez des patients ayant un equilibre compense. L’interet de l’imagerie rachis entier en charge est de determiner l’equilibre sagittal du patient et de s’assurer de l’absence de facteurs d’instabilites radiologiques qui pourraient justifier un geste stabilisateur. Niveau de preuve IV ; etude retrospective sur une collection prospective de donnees.

Resume Dans la chirurgie rachidienne degenerative de l’adulte, la cyphose jonctionnelle pourrait etre un mecanisme de compensation d’une hyperlordose lombaire pathologique, associee a une courbure spinale disharmonieuse. Nous presentons un cas qui a beneficie d’une decompression lombaire avec fusion thoraco-lombaire et des cages par abord posterieur et lateral. La patiente a developpe une cyphose jonctionnelle proximale et malgre plusieurs reprises chirurgicales, elle a continue de presenter des complications mecaniques en raison d’un exces de lordose lombaire. Nous avons finalement effectue une osteotomie posterieure d’ouverture (OPO ou Posterior Opening Wedge Osteotomy POWO) au niveau de L3 pour corriger l’hyperlordose lombaire. A 24 mois de suivi postoperatoire, aucune autre complication mecanique n’a ete mise en evidence. A travers cet article, nous exposons le raisonnement de ce type de traitement, ainsi que la procedure chirurgicale de l’OPO. Nous analysons egalement le risque lie a une correction excessive de la lordose lombaire entrainant une modification de la courbure harmonieuse de la colonne vertebrale degenerative chez l’adulte.

Objective: In this study, we investigate about relationship between postoperative global sagittal imbalance and occurrence of mechanical complications after adult spinal deformity (ASD) surgery. In global sagittal balance parameters, odontoid-hip axis (OD-HA) angle and T1 pelvic angle (TPA) were analyzed.Methods: Between January 2009 and December 2016, 199 consecutive patients (26 males and 173 females) with ASD underwent corrective fusion of more than 4 levels and were followed up for more than 2 years. Immediate postoperative and postoperative 2 years whole spine x-rays were checked for evaluating immediate postoperative OD-HA, TPA, and other parameters. In clinical outcomes, back and leg pain visual analogue scale, Scoliosis Research Society-22 spinal deformity questionnaire (SRS-22), Oswestry Disability Index (ODI), 36- item Short Form Health Survey (SF-36) were evaluated.Results: Based on the occurrence of mechanical complications, a comparative analysis was performed for each parameter. In univariable analysis, mechanical complications were significantly much more occurred in OD-HA abnormal group (odds ratio [OR], 3.296; p < 0.001; area under the curve [AUC] = 0.645). In multivariable analysis, the result was much more related (OR, 2.924; p = 0.001; AUC = 0.727). In contrast, there was no significant difference between normal and the occurrence of mechanical complications in TPA. In clinical outcomes (normal vs. abnormal), the differences of SRS-22 (0.88 ± 0.73 vs. 0.68 ± 0.64, p = 0.042), ODI (-24.72 ± 20.16 vs. -19.01 ± 19.95, p = 0.046), SF-36 physical composite score (19.33 ± 18.55 vs. 12.90 ± 16.73, p = 0.011) were significantly improved in OD-HA normal group.Conclusion: The goal of ASD surgery is to improve patient life quality through correction. In our study, TPA was associated with spinopelvic parameter and OD-HA angle was associated with health-related quality of life and complications. OD-HA angle is predictable factor for mechanical complications after ASD surgery.

Study design National cross-sectional study. Background Thoracic kyphosis (TK) is related to sagittal parameters as pelvic tilt (PT), lumbar lordosis (LL) and pelvic incidence (PI). The equation TK =2 (PT+LL–PI) was validated for adolescents. Objective: to investigate if this equation correctly predicts TK regardless of age. Methods Sagittal alignment parameters were assessed on full spine radiographs of 2599 individuals without spine pathology (1488 females, 1111 males). Calculated TK (CTK) = 2 (PT+LL–PI) and measured TK (MTK) were compared by calculating the gap and using a linear regression between both parameters. Subgroup analyses were performed for gender, age, TK groups (≤20°, 21°-40°, 41°-60°, >60°), and PI groups (60°). Results Average values in the total population were: MTK 45.0°, CTK 36.9°. Average TK gap was 8.1°, 5.2° in females (intercept 11.7, slope .61) and 11.9° in males (intercept 7.1, slope .58). The mean gap was 3.6° for 15-34 years, 5.7° under 15 years and it increased progressively after 35 years with a maximum of 19.9° over 80 years. The gap also increased with the amount of MTK: -3.5° for TK60°. Differences in gaps were minor between PI groups. The intercept was smallest and slopes >.6 for PI Conclusion The formula TK=2 (PT+LL-PI) yielded moderate accuracy for adolescents and young adults, but did not fit for over 35 years and under 15. The amount and variance in TK increased in elderly subjects, which made the formula less accurate.

Objective: The role of the craniocervical complex in spinal sagittal alignment has rarely been analyzed but it may play a fundamental role in postoperative mechanical complications. The aim of the study is to analyze the normative value of the cervical inclination angle (CIA) in an adult asymptomatic multiethnic population.Methods: Standing full-spine EOS of adult asymptomatic volunteers from 5 different countries were analyzed. The CIA was analyzed globally and then in each decade of life. Different ethnicities were compared. Comparisons between different groups was performed using a t-test and statistical significance was considered with a p-value < 0.05.Results: EOS of 468 volunteers were analyzed. The global mean CIA was 80.2° with a maximum difference of 9° between T1 and T12 (p < 0.001). The CIA remains constant until 60 years old then decreases significantly passing from a mean value before 20 years old of 82.25° to 73.65° after 70 years old. A statistically significant difference was found between the Arabics and other ethnicities with the formers having an inferior CIA: this was related to a mean older age (p < 0.05) and higher body mass index (p < 0.05) in the Arabics.Conclusion: The CIA remains constant until 60 years old and then reduces slightly but never under 70°. This angle is helpful to evaluate the lever arm at the upper instrumented vertebra after an adult spinal deformity surgery and could predict the occurrence of a proximal junctional kyphosis when its value is lower than normal. Further clinical studies must confirm this theory.

In a population of asymptomatic volunteers across 5 countries, we sought to: (a) establish normative values of the Odontoid-Central Sacral Vertical Line (OD-CSVL) across patient factors, and (b) assess correlations of OD-CSVL with other radiographic parameters. A prospective, cross-sectional study of asymptomatic adult volunteers, ages 18–80 years, were enrolled across 5 countries (France, Japan, Singapore, Tunisia, United States) forming the Multi-Ethnic Alignment Normative Study (MEANS) cohort. Included volunteers had no known spinal disorder(s), no significant neck/back pain (VAS ≤ 2; ODI ≤ 20), and no significant scoliosis (Cobb ≤ 20°). Radiographic measurements included commonly used coronal alignment parameters (mm) and angles (°). OD-CSVL was defined as the difference between the odontoid plumb line (line from the tip of the odontoid vertically down) and the CSVL (vertical line from the center of the sacrum). Chi-square, student’s t tests, Kruskal–Wallis, Wilcoxon rank-sum, linear regression, and Pearson’s correlation were used with significance at p

Highlight risk factors for pseudarthrosis in long-segment spinal fusions, collect the approaches carried to address this complication. Patients with ASD and fusion of ≥ 4 levels with minimum follow-up (FU) of ≥ 2 years were included. Full-body X-rays were done preoperatively

Background Transforaminal lumbar interbody fusion (TLIF) represents a commonly performed spinal procedure that poses a significant financial burden on patients, hospitals and insurers. Reducing these costs, while maintaining efficacy, may be assisted by a new powered endplate preparation device, designed to shorten procedural time while offering positive impacts on other elements that contribute to the cost of care. Objective The aim of the study was to assess and compare the individual cost elements of TLIF procedures with and without the use of the device, to determine whether application of this technology translated into any material procedural savings. Methods The records of 208 single-level TLIF procedures in a single hospital were reviewed. Surgical time, length of hospital stay, blood loss, infection rate, and other parameters were compared for the cases where the device was used (device group; n = 143) and cases which used standard tools (control group; n = 65). The cost per unit of each element was derived from the literature, online resources, and the hospital’s financial department. Results The analysis revealed a shorter surgery duration in the device group (23 min, after controlling for procedure year and patient characteristics; statistically significant at p

The objective is to analyse peri-operative blood loss (BL) and hidden blood loss (HBL) rates in spinal deformity complex cases surgery, with a focus on the strategies to prevent major bleeding.We retrospectively analysed surgical and anaesthesiologic data of patients who had been operated for adolescent idiopathic scoliosis (AIS) or adult spinal deformities (ASD) with a minimum of five levels fused. A statistical comparison among AIS, ASD without a pedicle subtraction osteotomy (PSO) (ASD-PSO( -)) and ASD with PSO (ASD-PSO( +)) procedures was performed with a view to identifying patient- and/or surgical-related factors affecting peri-operative BL and HBL.One-hundred patients were included with a mean 9.9 ± 2.8 fused vertebrae and a mean 264.2 ± 68.3 minutes operative time (OT) (28.3 ± 9 min per level). The mean perioperative BL was 641.2 ± 313.8 ml (68.9 ± 39.5 ml per level) and the mean HBL was 556.6 ± 381.8 ml (60.6 ± 42.8 ml per level), with the latter accounting for 51.5% of the estimated blood loss (EBL). On multivariate regression analysis, a longer OT (p 0.05; OR 3.38) and performing a PSO (p 0.05; OR 3.37) were related to higher peri-operative BL, while older age (p 0.05; OR 2.48) and higher BMI (p 0.05; OR 2.15) were associated to a more significant post-operative HBL.With the correct use of modern technologies and patient management, BL in major spinal deformity surgery can be dramatically reduced. Nevertheless, it should be kept in mind that 50% of patients estimated losses are hidden and not directly controllable. Knowing the per-level BL allows anticipating global losses and, possibly, the need of allogenic transfusions.

A non-comparative multi-centre and international pilot study have been carried on Y-STRUT® (Hyprevention, France), an implantable medical device meant to reinforce the hip to reduce the risk of a contralateral hip fracture. Objectives of the study were to determine the feasibility and tolerance of the procedure. Methods Patients older than 60 years were recruited when presenting at the emergency departments with a low-energy pertrochanteric fracture on one side and with a fracture risk assessed for the contralateral side with BMD, T-Score or other bone quality evaluation tool, FRAX index, or fall risk assessment. Pain and functional ability were assessed at the different follow-up visits using VAS, WOMAC and OHS-12 scores. Results Twelve patients were included and reached a one-year follow-up. Mean age was 82 years old (65 – 91). The average hospital stay was 13 days (3 – 29). The prophylactic surgery did not delay the hospital discharge for any patient. The procedure did not lead to unresolvable serious adverse events. At 3 weeks, all patients were able to walk 6 meters, half of them in less of 30 seconds. Minimal pain was reported all along the follow-up visits, except at 3 years when one patient presented high pain in both hips. WOMAC and OHS-12 scores showed a moderate to mild hip impairment. Conclusion The good short and medium-term outcomes of this pilot study demonstrate the feasibility and the tolerability of the device. Further studies should focus on the efficacy of this immediate and lasting bone reinforcement technique.

Retrospective cross-sectional study.The aim was to describe spinopelvic alignment types by pelvic incidence (PI) and age to compare the Roussouly classification between pediatric and adult populations.The Roussouly classification was validated for adults. Alignment types may vary during growth.Radiographs of 1706 non pathologic individuals (5-49 yr) were analyzed. Individuals ≤19 years were stratified by chronological age and skeletal maturity (triradiate cartilage, Risser), and compared with adults. Global and spinopelvic alignment parameters were assessed. Roussouly Types 1, 2, 3, 3A (anteverted pelvis), and 4 were determined. The distribution of parameters was analyzed by Bayesian inference. The relationship between PI and age by Roussouly type was modeled by linear regression.The Sagittal Vertical Axis C7 decreased during growth and was significantly smaller in adults (20-34 yr) (Pr0.99). Thoracic kyphosis and lumbar lordosis increased during growth and were larger in adults (Pr0.025). Lordosis increased mainly in the cranial arch (Pr0.025). PI and pelvic tilt increased during growth and were larger in adults (Pr0.025). In children and adolescents, PI45° represented the largest proportion, significantly larger compared with adults (Pr0.99). Proportions of Roussouly Types 1 and 2 were similar throughout ages. Types 3 and 4 were rarer during the prepubertal period (Pr0.025). The proportion of Type 3A was significantly higher in children and adolescents (Pr0.99). Linear regression showed that Type 4 had the largest PI increase with age, with significantly higher curve slope compared with other types (Pr0.9999). Types 3, 3A and 2 had similar slopes and lowest PI increase with age.Global and spinopelvic alignment changed during childhood and adolescence, leading to different kyphosis and lordosis distribution compared with adults. Growth-related PI increase influenced Roussouly types with typical predominance of Type 3A in the pediatric population and larger PI increase in Type 4.Level III.

The sacroiliac joint (SIJ) is a complex anatomical structure located near the centre of gravity of the body. Micro-traumatic SIJ disorders are very difficult to diagnose and require a complete clinical and radiological examination. To diagnose micro-trauma SIJ pain it is recommended to have at least three positive provocative specific manoeuvres and then a radiologically controlled infiltration test. Conservative treatment combining physiotherapy and steroid injections is the most common therapy but has a low level of efficiency. SIJ thermolysis is the most efficient non-invasive therapy. SIJ fusion using a percutaneous technique is a solution that has yet to be confirmed on a large cohort of patients resistant to other therapies. Cite this article: EFORT Open Rev 2020;5:691-698. DOI: 10.1302/2058-5241.5.190081

Although cervical spinal deformity (CSD) can have a profoundly negative impact on an individual’s quality of life and there have been many advances in surgical treatment of CSD in recent years, there exists no comprehensive classification system of surgical treatment that categorizes anterior and posterior surgery separately according to the grade of surgery. The objective of this study is to introduce the new classification system of various surgical treatments for CSD. We developed a new classification system (SOF system) for CSD surgery that describes the sequence of surgical approach (S), the grade of osteotomy (O), and the information of fixation (F) using alphanumeric codes. This new classification system can provide a consistent description of the various osteotomies performed in CSD surgery. Especially, regarding research, there has been a clear benefit to this classification. Having a standardized classification that allows for common frame for cervical deformity correction surgery, communication between surgeons and the evaluation of the CSD surgeries make it possible to conduct global comparative research about surgical outcome.

Since the outbreak of coronavirus disease 2019 (COVID-19) in December 2019 in China, various measures have been adopted in order to attenuate the impact of the virus on the population. With regard to spine surgery, French physicians are devoted to take place in the national plan against COVID-19, the French Spine Surgery Society therefore decided to elaborate specific guidelines for management of spinal disorders during COVID-19 pandemic in order to prioritize management of patients. A three levels stratification was elaborated with Level I: Urgent surgical indications, Level II: Surgical indications associated to a potential loss of chance for the patient and Level III: Non-urgent surgical indications. We also report French experience in a COVID-19 cluster region illustrated by two clinical cases. We hope that the guidelines formulated by the French Spine Surgery Society and the experience of spine surgeons from a cluster region will be helpful in order optimizing the management of patients with urgent spinal conditions during the pandemic.

Spine is a complex and long structure in the human body. Visualization of the spine is essential to treat and manage spine disease and commonly requires further imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI). In most clinical fields, spine CT and MRI examinations are focused on the region of interest. However, spine is composed of cervical, thoracic, lumbar, sacrum and coccyx and sometimes demands examination of entire structure as well as regional spine depending on disease, patient’s state and physician’s decision. This review considers the available literature to describe when and how full length spine evaluation by CT and MRI is applied according to each spinal disease such as spinal trauma, deformity, infection, axial spondyloarthropathy and metastatic tumor.

Multicenter Cohort.Assess normative values of sagittal spinal and lower extremity alignment in asymptomatic volunteers stratified by age and gender.Our understanding of ideal sagittal alignment is still evolving. The Multiethnic Alignment Normative Study (MEANS) investigated skeletal alignment of the largest multiethnic cohort of asymptomatic adult volunteers. We aim to assess normative values of sagittal spinal and lower extremity alignment in asymptomatic volunteers stratified by age and gender.Asymptomatic volunteers between the ages of 18-80 years were enrolled prospectively and then analyzed retrospectively from six different centers. Volunteers included reported no significant neck or back pain, nor any known spinal disorder(s). All volunteers underwent a standing full-body or full-spine low-dose stereoradiograph.MEANS consisted of 468 volunteers with a mean age of 40.4±14.8 years. Thoracic kyphosis (TK) from T4 to T12 showed a mean of 37.4±10.9°. The average L1-S1 lumbar lordosis (LL) was -57.4±11.3°. LL did not show significant differences across the five age groups. TK showed a significant difference based on age ( P0.0001). Sagittal vertical axis increased across age groups from -14.2 mm in young adults to 17.0 mm in patients64. Similar trend was seen for T1 pelvic angle with a mean of 5.0° in young adults and 13.7° in those older than age 64. Knee flexion increased across age groups without a significant change in odontoid-knee distance which is a surrogate for the center of the head aligned over the knees.In asymptomatic volunteers, sagittal alignment parameters showed a slow and steady change across age groups exemplified by an increase in TK. However, LL did not show a significant decrease across age groups. Volunteers used compensatory mechanisms such as slight pelvis retroversion, knee flexion, and neck extension to maintain an aligned sagittal posture with their head centered over their knees (odontoid-knee).3.

Full-length spine CT and MRI play a significant role in diagnosis and management of spinal trauma and disease. Full-length spine CT helps diagnose unforeseen injuries to the spine that may be missed due to concomitant or patient conditions in high-energy and multiple trauma patients. In the patient with complex or severe deformity, full-length spine CT facilitates analysis of the deformed anatomy and establishes a preoperative plan. Neurological structures and intraspinal anomalies can be visualized by full-length MRI, thereby preventing neurological complications after deformity surgery. In multifocal spinal infections, the entire spine should be evaluated through MRI to evaluate the extension of infection and plan for treatment. Spondyloarthropathy can be detected early in its disease course with the help of full-length spine MR imaging, including SI joints. Metastasis to the spine is probably the most common indication for full-length imaging as it allows evaluation of bone marrow change through whole spine MRI, especially in the setting of metastasis from prostate cancer and multiple myeloma. Due to the development of technology, taking time for CT and MRI of entire spine is becoming a more efficient process and the resolution is increasing. Specifically, in the case of CT, the radiation exposure is gradually reducing. These changes will expand the indications for examining full-length spine imaging and help diagnose, treat, and follow up with patients presenting with spine trauma and disease.

This is a cross-sectional cohort.The aim was to describe sagittal plane alignment and balance in a multinational cohort of nondegenerated, asymptomatic adults.Current sagittal alignment targets were developed using correlations between radiographic and quality-of-life measures in spinal deformity patients, rather than disease-free samples leading to relatively poor accounting for variance within a population.Sagittal balance was defined using vertebral body tilt and spinopelvic alignment was defined as the vertebral pelvic angles from C2 to L5 (vertebral pelvic angle=vertebral tilt+pelvic tilt). Associations with pelvic incidence (PI) were assessed using linear regression. Multivariable linear regression was used to estimate a normal L1-S1 lordosis, adjusting for PI and the L1 pelvic angle (L1PA). Correlation between the L1 and T4 pelvic angles was assessed to define a normal thoracic alignment conditioned on lumbar alignment.Among 320 volunteers from 4 continents, median age was 37% and 60% were female. C2 tilt was independent of PI with minimal variation. PI was inadequate for estimating a normal lumbar lordosis (L1-S1, r2 =0.3), but was strongly associated with the lumbar pelvic angles (L1PA, r2 =0.58). Defining lumbar lordosis as a function of PI and L1PA resulted in high explained variance ( R2 =0.74) and the T4 pelvic angle had near perfect correlation with the L1PA ( r =0.9).We defined normal sagittal balance and spinopelvic alignment in a disease-free international volunteer cohort. Four parameters are either fixed or directly modifiable in surgery and can define a normal thoracic and lumbar alignment: the L1-S1 lordosis defined as a function of PI and the L1PA; and the T4 pelvic angle is nearly equivalent to the L1PA, aligning the T4-L1-hip axis.

Sagittal balance (SB) plays an important role in the surgical treatment of spinal disorders. The aim of this research study is to provide a detailed evaluation of a new, fully automated algorithm based on artificial intelligence (AI) for the determination of SB parameters on a large number of patients with and without instrumentation.Pre- and postoperative sagittal full body radiographs of 170 patients were measured by two human raters, twice by one rater and by the AI algorithm which determined: pelvic incidence, pelvic tilt, sacral slope, L1-S1 lordosis, T4-T12 thoracic kyphosis (TK) and the spino-sacral angle (SSA). To evaluate the agreement between human raters and AI, the mean error (95% confidence interval (CI)), standard deviation and an intra- and inter-rater reliability was conducted using intra-class correlation (ICC) coefficients.ICC values for the assessment of the intra- (range: 0.88-0.97) and inter-rater (0.86-0.97) reliability of human raters are excellent. The algorithm is able to determine all parameters in 95% of all pre- and in 91% of all postoperative images with excellent ICC values (PreOP-range: 0.83-0.91, PostOP: 0.72-0.89). Mean errors are smallest for the SSA (PreOP: -0.1° (95%-CI: -0.9°-0.6°); PostOP: -0.5° (-1.4°-0.4°)) and largest for TK (7.0° (6.1°-7.8°); 7.1° (6.1°-8.1°)).A new, fully automated algorithm that determines SB parameters has excellent reliability and agreement with human raters, particularly on preoperative full spine images. The presented solution will relieve physicians from time-consuming routine work of measuring SB parameters and allow the analysis of large databases efficiently.

Retrospective cross-sectional study.The aim was to describe existing global sagittal alignment parameters across ages and to analyze differences according to gender and pelvic incidence (PI).Variability with age has been reported. It remains unclear how gender and spinopelvic morphology could additionally influence global alignment parameters.Radiographs of 2599 individuals (5-93 y) were analyzed. Translation parameters were: Sagittal Vertical Axis (SVA)-C7, SVA-C2, SVA-Center Acoustic Meatus (CAM), C7/Sacrofemoral Distance (SFD) ratio. Inclination parameters were: C7-Vertical Tilt (VT), T1-VT and T9-VT, Odontoid-Hip Axis (OD-HA), OD-CAM. Pelvic compensation parameters were: T1-Pelvic Angle (TPA), Global Tilt (GT), Spino-Sacral Angle (SSA). Global sagittal alignment (GSA) was considered among formulae. The distribution of parameters was analyzed using a Bayesian inference. Correlations with spinopelvic parameters were investigated.SVA-C7, SVA-C2, SVA-CAM were larger in males and high PI, and increased significantly after 50 years (Pr0.9999). C7/SFD decreased during growth and was larger in low PI (Pr=0.951). There was no correlation with spinopelvic parameters. Age-related variations of inclination parameters were nonsignificant. T1-VT and T9-VT increased with PI and were significantly larger in high PI (Pr0.95). C7-VT was significantly larger in low PI (Pr0.9999). OD-HA and OD-CAM were constant and increased after 80 years. TPA and GT increased with PI (Pr0.9999) and age after 35 years (Pr0.9999). SSA decreased nonsignificantly after 50 years. TPA correlated with PI (ρ=0.6130) and pelvic tilt (PT) (ρ=0.8375). GT correlated with PI (ρ=0.5961) and PT (ρ=0.8996). SSA correlated with sacral slope (ρ=0.9026). GSA was larger in high PI (Pr0.9999) and increased after 35 years (Pr0.9999). GSA correlated with PT (ρ=0.7732).Translation parameters increase with age, more prominently in males and high PI. Variations of inclination parameters are smaller. Pelvic compensation parameters and GSA increase with age and are closely related to PT and spinopelvic morphology.Level III.

The aim was to describe radiographic cervical sagittal alignment variations according to age, gender and pelvic incidence (PI) and to investigate relationships with thoracic alignment.A total of 2599 individuals (5-93 years) without spinal deformity were studied. Cranial cervical parameters were: McGregor slope, occipita-C2 angle, McGregor-C2 lordosis and C1-C2 lordosis. Caudal cervical parameters were: C2-C7, cranial arch and caudal arch lordosis and C7- and T1-slope. A Bayesian inference compared parameter distributions. Correlations with spinopelvic and global alignment parameters were investigated.Among cranial cervical parameters, variations of McGregor slope were non-significant. McGregor-C2 lordosis and C1-C2 lordosis were smaller in males and increased significantly during growth, whereas the occipito-C2 angle decreased (Pr 0.95). The occipito-C2 angle was larger and McGregor-C2 lordosis was smaller in low PI (Pr 0.95). Among caudal cervical parameters, C2-C7 lordosis and C7- and T1-slope were larger in males and increased after 50 years (Pr 0.95). Lordosis changes were non-significant in the cranial arch, whereas values increased in the caudal arch after 35 years (Pr 0.95). Caudal parameter differences were non-significant between PI groups. Strong correlations existed between C2-C7, caudal arch lordosis, C7-slope, T1-slope and thoracic kyphosis. The sagittal vertical axis C2 correlated with caudal arch lordosis and T1-slope (ρ 0.5; Pr 0.95).Cervical alignment parameters vary according to age, gender and PI. In the cranial cervical spine, changes occur mainly during growth. In the caudal cervical spine, lordosis increases in the caudal arch, which is related to thoracic kyphosis increase with age. The caudal cervical arch acts as a compensatory segment by progressive extension, allowing horizontal gaze.

Previous studies on adults with degenerative scoliosis (ADS) have been fixed the threshold of PI-LL mismatch less than 10° for achieving good clinical outcomes. Recent studies discussed that PI-LL mismatch should consider individual pelvic incidence (PI) and should be set first in a normal population. The purpose of this study is to assess the variability of PI-LL mismatch according to PI in an asymptomatic population.Full-body low dose stereoradiographic evaluation was done in a multi-ethnic cohort of 468 asymptomatic adult volunteers. Patients were clustered in three groups depending on individual PI values: PI 45°, 45° PI 60° and PI 60°. 3D measurements were performed using a commercially available 2D/3D modeling software to establish a correlation of PI with other spinopelvic parameters. ANOVA and Tukey's HSD for post-hoc analysis were used to determine the differences between the three groups.In our asymptomatic population, the mean value of PI-LL mismatch is - 5.4° ± 10.7°. Clusterization of the population reveals significant differences in the distribution of L1S1 lordosis, pelvic tilt and PI-LL with positive linear correlation according to PI values. As an interestingly result, PI-LL mismatch is equal to 0° when PI is around 64°.The present study demonstrated that PI-LL mismatch is negative in an asymptomatic population (- 5.4° ± 10.7°) and the value should be customized to each patient to be able to restore the appropriate lordosis in ADS. The PI-LL mismatch is given by the formula PI-LL = - 28.5 + 0.44 × PI.

Spinal alignment can have a significant impact on a patient's overall quality of life. Predicting the ideal sagittal spinal alignment of a specific individual is still a difficult task. The Multi-Ethnic Alignment Normative Study (MEANS) investigated skeletal alignment, including the spine and lower extremities, of the largest multi-ethnic cohort of asymptomatic adult volunteers. In this analysis, the authors aim to assess normative values of spinopelvic parameters and the regional cervical, thoracic, and lumbar spinal alignment in asymptomatic volunteers stratified by age and sex.Asymptomatic volunteers between ages 18 and 80 years were enrolled prospectively from centers in France, Japan, Singapore, Tunisia, and the United States. Volunteers included reported no significant neck or back pain (Visual Analog Scale ≤2), nor any known spinal disorder(s). All volunteers underwent a standing full-body or full-spine low-dose stereoradiograph.MEANS consisted of 468 volunteers with a mean age of 40.4±14.8 years. Mean cervical lordosis from C2 to C7 was -0.4±12.7°. The T1-slope averaged 23.0±7.9° and showed strong correlation ( r =0.87) with the C7-slope mean of 19.8±8.6°. Thoracic kyphosis (TK) from T4 to T12 showed a mean of 37.4±10.9°. Average L1-S1 lumbar lordosis (LL) was -57.4±11.3°. The mean pelvic incidence (PI) measured 52.0±10.7° and pelvic tilt was 12.5±7.3°. Sacral slope averaged 39.5±8.2°. The average PI-LL was -5.4±10.7°. Approximately 60% of volunteers met the PI-LL criteria within ±10°, 8.3% were ≥10°, while 32.1% were ≤-10°. LL showed moderate correlation with PI ( r =0.53) and TK ( r =0.50), while there was no correlation between TK and PI. Multiple linear regression including PI, TK, and age resulted in the following equation LL=14.6+0.57 (PI)+0.57 (TK)-0.2 (age) ( r =0.75).LL did not change with increasing age in asymptomatic volunteers. However, TK did increase with age leading to an increase in T1-slope and a compensatory increase in cervical lordosis. TK did not correlate with PI and was an independent variable in the prediction of LL.Level II-prospective cohort study.

Background and Aim: Hangman’s fracture concomitant with atlantoaxial subluxation is a rare phenomenon. Herein we report the victim of a motor vehicle crash with traumatic spondylolisthesis of the axis and atlantoaxial rotary dislocation. Case Presentation: The patient was a 32 year old female with the chief complaint of severe neck pain. Her neurologic examination was normal but did reveal mild torticollis. Imaging revealed anterolisthesis of the C2 over C3 with angulation of C1/ C2 and rupture of the C2/ C3 disc while the integrity of the transverse ligament was preserved. The patient first underwent a partial close reduction for the dislocation followed by the operation focusing on the Hangman’s fracture using a 360-degree approach. An anterior discectomy of C2/ C3 with cage and plate insertion was followed by posterior fixation using C1, C3 and C4 lateral mass screws. The one-year follow-up radiography depicted proper fusion and alignment. Conclusion: Paucity of evidence regarding simultaneous atlantoaxial dislocation and Hangman’s fracture made its management challenging. The mechanism of injury is probably hyperextension and rotation. Based on our presented case, anteroposterior fixation resulted in a satisfactory long-term outcome, both clinically and radiologically.

Unfortunately, the affiliation of the second author (Jean Charles Le Huec) was incorrectly published in the original publication.

Background In patients with osteoarthritis (OA) and an intact rotator cuff, hemi-shoulder arthroplasty (HSA) can be a viable option as it offers the advantage of keeping the native glenoid intact. However, glenoid erosion has frequently been reported. The aim of this study was to report preliminary clinical results of HSA with a new pyrolytic carbon (pyrocarbon) humeral head. Methods This prospective multicenter study included a continuous series of 65 patients who underwent pyrocarbon HSA in 5 centers. Results At the time of analysis, 1 patient was lost to follow-up, 3 patients underwent revision, and 61 patients were evaluated at a mean follow-up of 25.9 ± 3.3 months. The mean age at index surgery was 57.9 ± 13.3 years. The indications were primary glenohumeral OA in 37 patients, osteonecrosis in 11, secondary OA in 11, and rheumatoid arthritis in 2. The mean Constant score increased from 31.0 ± 15.8 points at baseline to 74.6 ± 17 points at last follow-up. Radiographic analyses showed that 86% of glenoids remained unchanged whereas 14% evolved slightly. Conclusions Pyrocarbon HSA grants improvement in pain and function in patients with primary OA or secondary OA after instability but at a lower level in patients with post-traumatic sequelae (secondary OA or osteonecrosis). These preliminary clinical and radiologic results are encouraging, although they need to be confirmed by longer-term follow-up observations.

Study Design Electronic survey administered to Scoliosis Research Society members. Objective To determine the prevalence of minimally invasive surgery (MIS) techniques for the treatment of adult spinal deformity. Summary of Background Data There is a paucity of data available on the practice pattern, prevalence of minimally invasive spine surgery, and the preferred minimally invasive techniques in the treatment of adult spine deformity. Methods An electronic nine-question survey regarding individual usage pattern of minimally invasive spine surgery techniques was administered in 2016 to the members of the Scoliosis Research Society. Determinants included complexity in condition of patient population, prevalence of use of minimally invasive techniques in the surgeon's practice, prevalence of use of a particular MIS technique, strategy elected during surgery, adoption of staging of procedures and timing between staging of procedures. Results A total of 357 surgeons responded (61.3% response rate), and 154 (43.1%) of the respondents said that they use MIS as a part of their surgical treatment of adult spinal deformity. However, of these 154 respondents, 67 (43.5%) said that their MIS usage in deformity practice was between 1% and 20%. Only 11 (7.2%) said that they used MIS 81% to 100% of the time. The top MIS approaches that surgeons chose were MIS lateral lumbar interbody fusion 109 (70.59%) and MIS percutaneous screws 91 (58.8%). Conclusions The low rate of adoption of these techniques among the SRS members may be due to the false perception that there is not enough data to support that MIS techniques are better. This and the fact that a practitioner needs to be facile at different MIS techniques may be the true impediment to the adoption of MIS techniques in the treatment of ASD. Level of Evidence Level IV.

BACKGROUND: Enhanced Recovery After Surgery (ERAS) evidence-based protocols for perioperative care have led to improvements in outcomes in numerous surgical areas, through multimodal optimization of patient pathway, reduction of complications, improved patient experience\ud and reduction in the length of stay. ERAS represent a relatively new paradigm in spine surgery.\ud PURPOSE: This multidisciplinary consensus review summarizes the literature and proposes recommendations for the perioperative care of patients undergoing lumbar fusion surgery with an\ud ERAS program.\ud STUDY DESIGN: This is a review article.\ud METHODS: Under the impetus of the ERAS� society, a multidisciplinary guideline development\ud group was constituted by bringing together international experts involved in the practice of ERAS\ud and spine surgery. This group identified 22 ERAS items for lumbar fusion. A systematic search in\ud the English language was performed in MEDLINE, Embase, and Cochrane Central Register of\ud Controlled Trials. Systematic reviews, randomized controlled trials, and cohort studies were\ud included, and the evidence was graded according to the Grading of Recommendations, Assessment,\ud Development, and Evaluation (GRADE) system. Consensus recommendation was reached by the\ud group after a critical appraisal of the literature.\ud RESULTS: Two hundred fifty-six articles were included to develop the consensus statements for\ud 22 ERAS items; one ERAS item (prehabilitation) was excluded from the final summary due to\ud very poor quality and conflicting evidence in lumbar spinal fusion. From these remaining 21 ERAS\ud items, 28 recommendations were included. All recommendations on ERAS protocol items are\ud based on the best available evidence. These included nine preoperative, eleven intraoperative, and\ud six postoperative recommendations. They span topics from preoperative patient education and\ud nutritional evaluation, intraoperative anesthetic and surgical techniques, and postoperative multimodal analgesic strategies. The level of evidence for the use of each recommendation is presented.\ud CONCLUSION: Based on the best evidence available for each ERAS item within the multidisciplinary perioperative care pathways, the ERAS� Society presents this comprehensive consensus\ud review for perioperative care in lumbar fusion.

In a population of asymptomatic volunteers across 5 countries, we sought to: (a) establish normative values of the Odontoid-Central Sacral Vertical Line (OD-CSVL) across patient factors, and (b) assess correlations of OD-CSVL with other radiographic parameters.A prospective, cross-sectional study of asymptomatic adult volunteers, ages 18-80 years, were enrolled across 5 countries (France, Japan, Singapore, Tunisia, United States) forming the Multi-Ethnic Alignment Normative Study (MEANS) cohort. Included volunteers had no known spinal disorder(s), no significant neck/back pain (VAS ≤ 2; ODI ≤ 20), and no significant scoliosis (Cobb ≤ 20°). Radiographic measurements included commonly used coronal alignment parameters (mm) and angles (°). OD-CSVL was defined as the difference between the odontoid plumb line (line from the tip of the odontoid vertically down) and the CSVL (vertical line from the center of the sacrum). Chi-square, student's t tests, Kruskal-Wallis, Wilcoxon rank-sum, linear regression, and Pearson's correlation were used with significance at p 0.05.467 volunteers were included with normative OD-CSVL values by age decade, gender, BMI, and country. Mean ± SD OD-CSVL was 8.3 mm ± 6.5 mm and 31 (6.6%) volunteers were almost perfectly aligned (OD-CSVL 1 mm). A linear relationship was seen between OD-CSVL with both age (p 0.001) and BMI (p = 0.015). Significant variation was seen between OD-CSVL and 5 different ethnicities (p = 0.004). OD-CSVL correlated best with other coronal radiographic parameters, C7-CSVL (r = 0.743, p 0.001), OD-knee (r = 0.230, p 0.001), CAM-knee (r = 0.612, p 0.001), and regional TL cobb angle (r = 0.4214, p = 0.005).Among asymptomatic volunteers, increased OD-CSVL was significantly associated with increased age, increased BMI, and ethnicity, but not gender. OD-CSVL correlated strongest with C7-CSVL, TL cobb angle, OD-knee, and CAM-knee. OD-CSVL. These results support further study of OD-CSVL in symptomatic adult spine deformity patients.

Highlight risk factors for pseudarthrosis in long-segment spinal fusions, collect the approaches carried to address this complication.Patients with ASD and fusion of ≥ 4 levels with minimum follow-up (FU) of ≥ 2 years were included. Full-body X-rays were done preoperatively, 3 months and ≥ 2 years. Oswestry disability index (ODI), Scoliosis Research Society-22 and SF36 assessed pre- and postoperatively. The relationship between demographic, surgical and radiological variables with the development of pseudarthrosis was evaluated.Out of 524 patients included, 65 patients (12.4%) developed pseudarthrosis and 53 underwent revision surgery. Notably, 88% of pseudarthrosis cases are associated with fusion length (OR = 1.17, 95% CI = 1.05-1.292, p = 0.004), osteotomy requirement (OR = 0.28, 95% CI = 0.09-0.85, p = 0.025), pelvic fixation (OR = 0.34, 95% CI = 0.13-0.88, p = 0.026) and combined approaches (OR = 3.29, 95% CI = 1.09-9.91, p = 0.034). Sagittal alignment is not related to the rate of pseudarthrosis. Health related and quality of life scores were comparable at last FU between patients revised for pseudarthrosis and those that didn't require revision surgery (ODI = 28% no revision and 30% revision group).Pseudarthrosis is not related to malalignment, but with the surgical techniques employed for its treatment. Anterior approaches with anterior support decrease the rate by 30%, while long fusions, osteotomies and pelvic fixation increase its rate.

To develop and assess the reliability of new nomenclature system that systematically organizes osteotomy techniques and briefly describes the surgical approach, the surgical sequence, and the fixation technique for cervical spine deformity (CSD). We developed a new classification system (SOF system) for CSD surgery that describes the sequence of surgical approach (S), the grade of osteotomy (O), and the information of fixation (F) using alphanumeric codes. Twenty CSD osteotomies (8 anterior osteotomies, 12 posterior osteotomies) were included in this study to evaluate the inter- and intra-observer agreement based on operation records. Six observers performed independent evaluations of the operation records in random order. Each observer described 20 CSD surgeries using the SOF system twice (> 30 days between assessments) based on operation records to validate SOF system. Overall agreement (among all six observers at the initial assessment) on the anterior and posterior osteotomy was ICC = 0.96 and ICC = 0.91, respectively. Overall agreement (repeat observations after at least 30 days) on the anterior and posterior osteotomy was ICC = 0.96 and ICC = 0.91, respectively. This data showed that both inter- and intra-observer agreement revealed ‘excellent’. This study introduces the SOF system of the CSD surgery to understand the surgical sequence, the type of osteotomy and the fixation techniques. The investigation of the inter- and intra-observer agreement revealed ‘excellent agreement’ for both anterior and posterior osteotomies. Thus, SOF system can provide a consistent description of the various CSD surgeries and its use will provide a common frame for CSD surgery and help communicate between surgeons.

Introduction The need to combine fusion with decompression in patients with lumbar canal stenosis is still controversial. The aim of this study was to show that isolated decompression leads to the same outcomes as decompression plus fusion in patients who have preserved global sagittal balance. Materials and Methods A single-center retrospective cohort of 110 patients who were operated for a single-level lumbar stenosis was divided into two groups based on the treatment: isolated decompression or fusion-decompression. These patients had a normal odontoid-hip axis angle (ODHA) (−5° to +2°) and had no spondylolisthesis or frontal deformity. We compared the clinical outcome scores and spinal-pelvic parameters preoperatively and at 1 year of follow-up. We evaluated the minimal clinically important difference (MCID) corresponding to a 12.8-point difference in the Owestry Disability Index (ODI). The analysis in each group was based on the MCID. Results The clinical outcome scores improved significantly in both groups. There was a 77% decrease in the ODI > 12.8 points with no significant difference between groups. The analysis based on the MCID showed that patients with a poor clinical result at 1 year in the isolated decompression group were more likely to have lumbar pain, while the ones in the fusion-decompression group were more likely to have radicular pain. Conclusion The clinical and radiological results of fusion-decompression are not superior at 1 year relative to isolated decompression for treating single-level lumbar canal stenosis in patients with compensated sagittal balance. Full-spine weight bearing radiographs are key to determining the patient's sagittal balance and to ensuring there are no radiological instability factors that may require a stabilizing procedure. Level of evidence IV Retrospective study of data collected prospectively.

Purpose: There is insufficient information regarding axial plane characteristics of scoliosis despite its 3D nature. The posterior–anterior vertebral vector (VV) has been proposed to characterize the axial plane appearances of the thoracic scoliosis. This study aimed to highlight the importance of knowledge of axial plane features when determining fusion levels and correction techniques of thoracic curves. Methods: Altogether, 233 thoracic curves were analyzed using the VV after proving its usability instead of 3D angles to determine axial plane parameters such as apical vertebral (APV) axial rotations, APV lateral displacement, and intervertebral rotations (IVR). K-means clustering and regression analysis were used to identify axial plane curve patterns and determine the relationship between the coronal angles and axial plane characteristics, respectively. Results: A close correlation was found between 3D angles and VV projected angles. Eight axial plane clusters were distinct, exhibiting different lateral APV displacement toward the interacetabular axis with relatively small axial rotations and a simultaneous decrease in sagittal curves. The regression analysis showed that the correlation of coronal curve magnitude was significantly stronger (r = 0.78) with APV lateral translation than with APV axial rotation (r = 0.65). Conclusion: Based on these findings, the primary goal of scoliosis correction should focus on minimizing lateral translation rather than eliminating axial rotation. Knowing the IVR in the axial plane helps accurately determine the limits of the structural curves. VV-based axial views can facilitate the accurate determination of the end vertebrae and selection of the appropriate correction technique of the curve. Graphic abstract: These slides can be retrieved under Electronic Supplementary Material. [Figure not available: see fulltext.]