Sagittal Profile Research Articles

Sagittal Spinopelvic Alignment After Posterior Spinal Fusion in Adolescent Idiopathic Scoliosis: A Systematic Review and Meta-analysis.

A systematic review and meta-analysis. The aim of this study was to determine the differences in the sagittal spinopelvic parameters between the nonscoliotic controls, preoperative, and different time points postoperative in Lenke 1 and 5 adolescent idiopathic scoliosis (AIS). The postoperative changes in the sagittal profile of Lenke 1 and 5 AIS at varying time points after posterior spinal fusion (PSF) has not been rigorously demonstrated; studies performed have had conflicting results. Sagittal spinal and pelvic parameters, T5-T12 thoracic kyphosis (TK), L1-S1 lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), and sagittal vertical axis (SVA), for Lenke 1 and 5 preoperatively, at immediate, less than 2-year, and more than 2-year postoperatively, and for nonscoliotic adolescents were searched. Differences in the sagittal spinopelvic parameters between preoperative and the follow-ups and between the nonscoliotic and pre- and postoperative AIS subtypes were calculated through meta-analysis. A total of 22 studies on Lenke1 (1229 patients), 13 studies on Lenke5 (437 patients), and 18 studies on controls (1636 patients) were reviewed. Among all the measured variables, only PI in Lenke1 was significantly different between the final follow-up and controls, P < 0.05. In Lenke 1, SVA was significantly more anterior at the immediate postoperative than preoperative, but continued moving posteriorly up to 2-year postoperative resulting in no significant difference in the SVA position between the final follow-up and preoperative, P > 0.05. In Lenke 5, SVA was significantly more posterior at the immediate postoperative and more anterior at the final follow-up than the preoperative measurements, p < 0.05. Continuous changes in the sagittal spinal parameters should be expected after PSF. Normalization of the sagittal spinal parameters appears to be the rule after PSF, and watchful waiting appears to be appropriate in this population when viewing the lateral X-ray postoperatively. 4.

Spinopelvic parameters in patients with lumbar degenerative disc disease, spondylolisthesis, and failed back syndrome: Comparison vis-à-vis normal asymptomatic population and treatment implications.

Background:Most of the literature on role of spinopelvic parameters in various lumbar spine pathologies has been based on studies done on Caucasian population.Aims and Objectives:The present study attempts to establish a database of measurements of the sagittal profile of spine in asymptomatic Indian population and their comparison with subjects having various lumbar spine pathologies.Materials and Methods:We performed a prospective case control study at All India Institute of Medical Sciences, New Delhi in which we enrolled 109 patients and 22 healthy asymptomatic subjects in 2 years from 2015 to 2017. All patients underwent standing lateral radiographs of the pelvis and the entire spine and various spino-pelvic parameters were measured using Surgimap software.Results:The mean Pelvic incidence (PI) in the asymptomatic individuals was 49.29 ± 5.95° which was significantly lower when compared with patients of chronic low backache (53.96 ± 9.47, P-<0.001), lumbar listhesis (59.4 ± 21.33, P-<0.001) and failed back surgery syndrome (56.7 ± 8.21, P-<0.001). The mean Pelvic Tilt (PT) in healthy subjects was 14.3±4.08° which was significantly lower when compared with patients of lumbar listhesis (23.35 ± 14.03, P-<0.001) and failed back surgery syndrome (22.8 ± 8.09, P-<0.001). Sacral slope (SS) and sagittal vertical axis (SVA) offset did not show any statistically significant difference. The mean Lumbar lordosis (LL) measured in healthy individuals was 42.5 ± 7.89° which was significantly lower when compared with patients of lumbar listhesis (46.24 ± 19.24, P-0.04) and failed back surgery syndrome (45.12 ± 6.87, P-0.05).Conclusion:PT and PI showed statistically significant difference in subjects having lumbar spondylolisthesis and failed back surgery syndrome as compared to healthy asymptomatic subjects.

The Link Between the 3D Spino-pelvic Alignment and Vertebral Body morphology in Adolescent Idiopathic Scoliosis

BackgroundVertebral anterior overgrowth has been suggested as part of the etio-pathogenesis of adolescent idiopathic scoliosis (AIS). However, the link between 3D spinopelvic alignment and the vertebral anteroposterior height asymmetry in different scoliotic curves types and whether it deviates from the non-scoliotic controls, has not been studied. PurposeWe aimed to retrospectively describe the link between the anteroposterior vertebral height differences (ΔAPVH) measured in the true sagittal plane of each vertebra and the spinopelvic parameters in three anatomical planes. Methods30 AIS cases with primary thoracic curves, 28 with thoracolumbar/lumbar curves, and 20 non-scoliotic controls were included. All subjects had 3D reconstruction of the spine, generated from low-dose upright stereoradiography images. Pelvic incidence (PI), thoracic and lumbar coronal and sagittal curve measurements, and vertebral axial rotation were measured. The association between the spinopelvic parameters and ΔAPVH were compared between the two AIS and control groups. ResultsΔAPVH at the apex of the curve was significantly different between the two AIS groups, as well as between both AIS groups and the controls and was related to the vertebral apical rotation (p < 0.05). Kyphosis and lordosis measurements were significantly related to the sum of the ΔAPVH in thoracic and lumbar regions respectively in AIS group but not in non-scoliotic controls (p < 0.05). ConclusionsThe ΔAPVH depended on the scoliotic curve type and was significantly different from the controls only at the apical levels. Morphological changes in the scoliotic vertebrae, measured as anterior-posterior differences in the vertebral height, are related to the sagittal spinal profile suggesting the morphology of the vertebra contributes to the sagittal curvatures of the spine in AIS; nonetheless, such relationship between the vertebral morphology and the sagittal profile was not evident in non-scoliotic controls.

The 3D Sagittal Profile of Thoracic Versus Lumbar Major Curves in Adolescent Idiopathic Scoliosis

Study DesignRetrospective. ObjectiveTo compare the 3D sagittal profile of patients with main thoracic or thoracolumbar/lumbar adolescent idiopathic scoliosis (AIS) to a normal cohort. Summary of Background InformationThoracic AIS is often associated with a loss of kyphosis. Classically, this measure has been made in 2D, which may underestimate the true sagittal deformity. MethodsBiplanar upright radiographs were obtained on 152 primary thoracic (TH: Lenke 1–4), 50 primary thoracolumbar/lumbar (TL/L: Lenke 5–6) curves, and 89 normal controls (NC). 3D spinal reconstructions were created using sterEOS software. MATLAB code was used to create segmental measurements of kyphosis/lordosis for each vertebral and disc segment from T1 to S1 in the local coordinate system of each motion segment. Comparisons were made between groups for the 3D summed segmental measures (T1–T5, T5–T12, T12–S1), pelvic incidence, sacral slope, and pelvic tilt. ResultsMean 2D Cobb was 57°±12° (range 40°–115°) for TH curves and 52°±9° (range 37°–75°) for TL/L curves. Significant differences in 3D sagittal measures were found between the 3 groups. Post hoc tests revealed significant differences at T1–T5, TH<NC, and TL/L<NC. All groups differed from each other from T5–T12, with the least kyphosis in TH curves. T12–S1 lordosis was significantly greater in TH and TL/L curves compared with NC. Lumbar lordosis extended proximally an average of one segment in AIS compared to normal spines (T11 vs T12). Pelvic incidence, sacral slope, and pelvic tilt were significantly greater for TH curves compared to NC. ConclusionsThere is a substantial average loss of thoracic kyphosis (∼15°–25°) for both primary thoracic and primary thoracolumbar/lumbar AIS curves compared to normal adolescents. Three-dimensional assessment of scoliosis allows the “true” deformity to be measured by correcting for error due to out-of-plane measurement associated with conventional 2D measurements. Level of EvidenceLevel II, prognostic.

Nonsurgical and surgical management of osteoporotic vertebral body fractures : Recommendations of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU)

Prospective clinical cohort study (data collection); expert opinion (recommendation development). Treatment options for nonsurgical and surgical management of osteoporotic vertebral body fractures differ widely. Based on the current literature, the knowledge of the experts, and their classification for osteoporotic fractures (OF classification), the Spine Section of the German Society for Orthopaedics and Trauma has now introduced general treatment recommendations. Atotal of 707 clinical cases from 16hospitals were evaluated. An OF classification-based score was developed for guidance in the option of nonsurgical versus surgical management. For every classification type, differentiated treatment recommendations were deduced. Diagnostic prerequisites for reproducible treatment recommendations were defined: conventional X‑rays with consecutive follow-up images (standing position whenever possible), magnetic resonance imaging, and computed tomography scans. OF classification allows for upgrading of fracture severity during the course of radiographic follow-up. The actual classification type is decisive for the score. Ascore of less than 6points advocates nonsurgical management; in cases with more than 6points, surgical management is recommended. The primary goal of treatment is fast and painless mobilization. Because of the expected comorbidities in this age group, minimally invasive procedures are preferred. As ageneral rule, stability is more important than motion preservation. It is mandatory to restore the physiological loading capacity of the spine. If the patient was in acompensated unbalanced state at the time of fracture, reconstruction of the individual prefracture sagittal profile is sufficient. The instrumentation technique has to account for compromised bone quality. We recommend the use of cement augmentation or high purchase screws. The particular situations of injuries with neurological impairment, the necessity to fuse, multiple level fractures, consecutive and adjacent fractures and fractures in ankylosing spondylitis are addressed separately. The therapeutic recommendations presented here provide areliable and reproducible basis to decide for the treatment choices available. However, intermediate clinical situations with ascore of 6points remain, allowing for both nonsurgical and surgical options. As aresult, individualized treatment decisions may still be necessary. In the subsequent step, the recommendations presented will be further evaluated in amulticentre controlled clinical trial.

Biomechanical aspects of preoperative planning: What is really important?

Sagittal balance is dependent on acomplex interplay of the spinal curves, shape and setting of the pelvis, but also the position of the joints of the lower limb. Degenerative processes such as stiffening of the spine, aging of musculature, or reduction of the range of motion of the joints lead to imbalance of the spine after all compensatory mechanisms have been exhausted. Based on standardized imaging, compensation mechanisms must be identified within abiomechanical analysis of the spine, the original sagittal spine profile anticipated and included in the planning of the corrective intervention. This review presents the most important global and spinopelvic parameters for the biomechanical analysis of the spine. In addition, normal variations of the sagittal alignment are discussed, compensation mechanisms are shown, and the planning of the rebalancing of the sagittal alignment is shown according to the full balance integrated model.

BIOMECHANICAL MODELING IN SURGICAL TREATMENT OF A PATIENT WITH TRUE LUMBAR SPONDYLOLISTHESIS

Objective. To assess the results of clinical approbation of individual finite-element biomechanical model of a patient’s spino-pelvic complex with subsequent modeling of the best option of surgical treatment. Material and Methods. A biomechanical modeling of changes in the sagittal profile of a patient with degenerative disease of the lumbosacral spine, bilateral spondylolysis, and unstable grade 2 spondylolisthesis of the L4 vertebra was performed. The developed biomechanical model made it possible to assess the characteristics of the stress-strain state of the spinal motion segments aroused due to development of the disease. Within the built biomechanical model of the patient’s spino-pelvic complex, a corrective operation was further modeled that assumed a preservation of harmonious profile of sagittal spino-pelvic relationships. Post-correction characteristics of the stress-strain state of spinal motion segments were studied and compared with preoperative parameters of the biomechanical model. Results. Using methods of biomechanics and computer modeling allowed to calculate the stress-strain state of the lumbosacral spine under static load for two options of fixation and intervertebral cage implantation at the L4–L5 level: four transpedicular screws (L4–L5 vertebrae) and six transpedicular screws (L3–L4–L5 vertebrae). The simulation results showed that neither metal implants, nor elements of the lumbosacral spine experienced critical stresses and deformations that could lead to the destruction and instability of the implant. Conclusion. The developed individual biomechanical finite-element solid model of the spine and pelvis allowed for biomechanical justification of prerequisites for the formation and further progression of degenerative changes in spinal motion segments associated with violations of the sagittal profile due to grade 2 spondylolisthesis of the L4 vertebra. The model built on the results of radiological examination biomechanically substantiated the best option of corrective spine surgery allowing to minimize stresses and deformations by choosing reasonable magnitude of correction of sagittal spino-pelvic parameters and configuration of transpedicular system.

Development of New-Onset Cervical Deformity in Nonoperative Adult Spinal Deformity Patients With 2-Year Follow-Up.

Evaluate the presence of new-onset cervical deformity (CD) in nonoperative adult spinal deformity (ASD) patients with extended follow-up, with consideration for predictors, prevalence, and impact on patient-reported outcomes. Retrospective review of a prospective nonoperative ASD cohort. New onset CD patients at 1- (CD-1Y) and 2-year (CD-2Y) follow-up were defined as displaying baseline cervical alignment. Univariate analyses determined differences in radiographic parameters and outcome scores of CD and maintained-cervical-alignment patients. Multivariate binary logistic regression models determined new-onset CD predictors. A total of 143 patients were included (mean age 54 years, mean body mass index 25.6 kg/m2, 86% female). Cervical deformity rate was 38.5% at baseline. New-onset CD incidence at 1- and 2-year follow-up was 30.0% and 41.7%, respectively. Global sagittal profile comparison of CD-1Y/CD-2Y versus maintained cervical alignment cases revealed no differences (P > .05) at any interval. Baseline C2-C7 sagittal vertical axis (SVA) was associated with increased new-onset CD risk at 1 (odds ratio [OR] 1.14, P = .025) and 2 years (OR 1.04, P = .032); prior spine surgical history was associated with CD risk at 1-year follow-up (OR 6.75, P = .047); baseline C2 slope was associated with increased CD risk at 2-year follow-up (OR 1.12, P = .041). CD development did not significantly impact health-related quality of life (P > .05). Cervical deformity can manifest in nonoperative ASD patients: 30.0% at 1-year follow-up, and 41.7% at 2-year follow-up. Progressive CD manifested independently of thoracolumbar profile changes. Increased baseline C2-C7 SVA, C2 slope, and prior surgical history increased new-onset CD odds at 1 and 2 years.

Spine’s Sagittal Plane Curves’ Coherence with Anthropometric Parameters in Schoolchildren

The aim of this study — to identify how anthropometric measurements are connected with spine sagittal curves inschoolchildren.Anthropometric and sagittal body posture measurements were performed for 405 schoolchildren, age range 10—13years. Such anthropometric measurements as body height, weight, fat mass and fat free mass were assessed. Degreesof thoracic kyphosis and lumbar lordosis as sagittal profile features were evaluated.According to the data analysis could be concluded, that coherence between anthropometric parameters and spine’ssagittal profile differs according to gender. The number of statistically significant connections between these twoparameters’ groups was greater in boys. Anthropometric measurements had greater coherence with thoracic kyphosisin comparison with lumbar lordosis. Body weight and fat mass were statistically significantly different according tokyphosis and lordosis values in boys, although fat-free body mass had no significant difference with sagittal curves’expression. Body weight, fat mass and fat-free body mass among girls were associated only with thoracic kyphosis.Keywords: thoracic kyphosis, lumbar lordosis, height, weight, fat mass.

CLINICAL AND ROENTGENOLOGICAL CRITERIA OF SPINE-PELVIS RATIOS IN CHILDREN WITH DYSPLASTIC FEMUR SUBLUXATION

Aim of the study — to identify clinical and roentgenological criteria of the sagittal profile status of spine-pelvis segment in children with dysplastic femur subluxation.Material and Methods. The present study included 40 female patients (50 hip joints) aged from 12 to 17 years (14.7±1.58) with unilateral and bilateral hip joint instability due to dysplasia. Children were divided into two groups – the first group included 30 patients (30 hip joints) with unilateral femur subluxation, the second group – 10 patients (20 hip joints) with bilateral femur subluxation. All patients underwent a standard orthopaedic clinical examination using a specialized scale to objectify complaints. All patients underwent X-ray examination of hip joints in AP and Lauenstein projections, CT scanning as well as lateral panoramic roentgenography of C1-S1 including femoral bones in standing position of the patient.Results. The authors observed a strong positive correlation between sacrum inclination and lumbar lordosis curvature, antetorsion angle of proximal femur and sacrum inclination angle, severity of pain syndrome during impingement test and sacrum tilt: Pearson correlation coefficient was 0.71, 0.81 and 0.88 respectively. The authors reported in all patients a thoracic normokyphosis and lumbar hyperlordosis with excessive pelvis anteversion. Global sagittal disbalance was observed in all patients.Conclusion. Apart from typical anatomical and roentgenological changes in pelvic and femoral componentsof the joint the children with dysplastic femur subluxation are characterized by excessive pelvic anteversion. Criteria of above parameters are identical and do not depend on the number of joints involved into the pathological process. Cranial dislocation of femoral head results to abnormalities of sagittal spine-pelvis ratios. Pathological process in hip joints and abnormality of spine-pelvis ratios results in negative changes of sagittal spine profile in the form of hyperlordosis, of physiological criteria of thoracic kyphosis and of the global sagittal disbalance. All of the above leads to overload of spinal motion segments and development of spine degenerative and dystrophic changes at early age.

Efficacy of three-dimensionally integrated exercise for scoliosis in patients with adolescent idiopathic scoliosis: study protocol for a randomized controlled trial

BackgroundAdolescent idiopathic scoliosis (AIS) is one of the most prevalent spinal deformities that may progress sharply during growth. The aim of this study will be to evaluate the efficacy of three-dimensionally integrated exercise on the Cobb angle, angle of trunk rotation, sagittal profile, and quality of life in patients with AIS.Methods/designThe study is designed as a randomized controlled trial. Participants include 42 patients with AIS aged 10–16 years. Randomly assigned patients will follow a 6-month treatment, either in a control group with standard care of observation following the Scoliosis Research Society criteria or in an experimental group with three-dimensionally integrated exercise for scoliosis. Blinded assessments at baseline and immediately after intervention will include the change of Cobb angle, angle of trunk rotation, sagittal index, and quality of life.DiscussionIf we find that the intervention is effective in improving Cobb angle, angle of trunk rotation, sagittal profile, and quality of life in patients with AIS, this trial will have a positive impact and warrant a change in clinical practice.Trial registrationClinicalTrials.gov, NCT03427970. Registered on February 9, 2018, and revised on July 24, 2018.

Nonsurgical and Surgical Management of Osteoporotic Vertebral Body Fractures: Recommendations of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU).

Study Design:Prospective clinical cohort study (data collection); expert opinion (recommendation development).Objectives:Treatment options for nonsurgical and surgical management of osteoporotic vertebral body fractures are widely differing. Based on current literature, the knowledge of the experts, and their classification for osteoporotic fractures (OF classification) the Spine Section of the German Society for Orthopaedics and Trauma has now introduced general treatment recommendations.Methods:a total of 707 clinical cases from 16 hospitals were evaluated. An OF classification–based score was developed to guide in the option of nonsurgical versus surgical management. For every classification type, differentiated treatment recommendations were deduced. Diagnostic prerequisites for reproducible treatment recommendations were defined: conventional X-rays with consecutive follow-up images (standing position whenever possible), magnetic resonance imaging, and computed tomography scan. OF classification allows for upgrading of fracture severity during the course of radiographic follow-up. The actual classification type is decisive for the score.Results:A score of less than 6 points advocates nonsurgical management; more than 6 points recommend surgical management. The primary goal of treatment is fast and painless mobilization. Because of expected comorbidities in this age group, minimally invasive procedures are being preferred. As a general rule, stability is more important than motion preservation. It is mandatory to restore the physiological loading capacity of the spine. If the patient was in a compensated unbalanced state at the time of fracture, reconstruction of the individual prefracture sagittal profile is sufficient. Instrumentation technique has to account for compromised bone quality. We recommend the use of cement augmentation or high purchase screws. The particular situations of injuries with neurological impairment; necessity to fuse; multiple level fractures; consecutive and adjacent fractures; fractures in ankylosing spondylitis are being addressed separately.Conclusions:The therapeutic recommendations presented here provide a reliable and reproducible basis to decide for treatment choices available. However, intermediate clinical situations remain with a score of 6 points allowing for both nonsurgical and surgical options. As a result, individualized treatment decisions may still be necessary. In the next step, the recommendations presented will be further evaluated in a multicenter controlled clinical trial.

Sagittal Profile Response of Cervical Spine After Posterior Correction in Thoracic and Lumbar Adolescent Idiopathic Scoliosis: Correlation with Thoracic Kyphosis?

To analyze postoperative changes in cervical alignment in patients with adolescent idiopathic scoliosis (AIS) with different curve patterns. Radiographic data were retrospectively reviewed in 43 patients with AIS with right thoracic major curve versus 39 with major lumbar curve with a minimum of 2 years' follow-up. Radiographic parameters analyzed in this study included cervical sagittal parameters (cervical lordosis [CL], T1 slope, T1 slope minus C2-C7 lordosis, T1-spine, T1 pelvic angle, and C2-C7 sagittal vertical axis) and spinopelvic sagittal parameters obtained from radiographs. Paired t tests were used for comparison with 0.05 as a statistically significant threshold. At baseline, larger CL (5.69° vs.-5.12°, P= 0.002) and smaller T1 slope minus C2-C7 lordosis (9.26° vs. 17.09°, P= 0.001) was noted in patients with lumbar-curve adolescent idiopathic scoliosis (L-AIS), whereas preoperative thoracic kyphosis (TK) was not different between the 2 groups. When the immediate postoperative sagittal profiles were compared between the 2 groups, larger TK (23.72° vs. 18.86°, P= 0.009) and more obvious CL (7.26° vs.-2.60°, P= 0.001) were noticed in the L-AIS group. During the follow-up, larger TK and CL were still maintained in the L-AIS group. In addition, a significant correlation was found between the improvement of CL and TK restoration in patients with L-AIS (r=-0.473, P= 0.002). Correlations between the improvement of CL and TK highlight the importance of restoration of patients with normal TK or AIS. Reciprocal changes in cervical alignment may happen if the TK was also simultaneously restored in patients with AIS. For patients with different curve patterns, the cervical sagittal parameters tend to be similar during follow-up.

Pyogenic Spondylodiscitis of the Thoracic Spine: Outcome of 1-Stage Posterior Versus 2-Stage Posterior and Anterior Spinal Reconstruction in Adults

The aim of this study was to compare the clinical, radiologic, and functional outcomes of a 1-stage posterior treatment versus a 2-stage posterior-anterior treatment in patients with pyogenic thoracic spondylodiscitis. A 1-stage posterior debridement, stabilization, and fusion with titanium-coated polyetheretherketone (PEEK) or mesh cage through a dorsolateral approach was performed in group A. A 2-stage procedure with initial posterior stabilization and debridement and second-stage fusion with a PEEK cage or mesh cage was performed with an anterior approach in group B. Clinical outcomes included Oswestry Low Back Pain Disability Questionnaire and visual analog scale score. Radiologic outcomes included fusion rate and kyphotic angle correction. Secondary variables included pathogens, complications, blood loss, and operative time. One-level spondylodiscitis was treated surgically in the thoracic spine of 47 patients: 25 patients in group A and 22 patients in group B. The most frequent segment was T12-L1 (27%). There was a significantly longer operative time and greater blood loss (P > 0.001) in group B. At last follow-up, sagittal profile reconstruction was significantly better (P > 0.05) in group B. Both groups showed similar radiologic results with fusion in 92% of cases. Improved clinical outcomes, pain, and quality of life were achieved in both groups with no significant differences between the 2 groups. Better reconstruction of the sagittal profile was achieved in the posterior-anterior-treated group, but this did not affect the clinical outcome. No significant differences were found in the clinical and functional outcomes between the 2 groups. Posterior-anterior combined treatment should be considered in cases of large anterior defects if a posterior reconstruction is inadequate.

Sagittal Alignment After Surgical Treatment of Adolescent Idiopathic Scoliosis—Application of the Roussouly Classification

Study DesignRetrospective cohort study. ObjectivesTo investigate spinopelvic alignment and spine shape in patients surgically treated for adolescent idiopathic scoliosis (AIS) and to assess the distribution and clinical applicability of the Roussouly classification. Summary of Background DataHow spinopelvic alignment is affected in AIS patients is not well established. Roussouly et al. proposed a classification based on the sagittal spinal profile and spinopelvic alignment that may have clinical utility in these patients. MethodsA consecutive cohort of 134 surgically treated AIS patients were included. Whole-spine standing lateral radiographs were analyzed preoperatively, one-week postoperatively and at two-year follow-up. Patients were categorized using the modified Roussouly classification and analyzed for sagittal alignment. ResultsPostoperatively, global thoracic kyphosis (TK) decreased by 2.6° and lumbar lordosis (LL) decreased by 6.2°(p ≤ .012) while Pelvic tilt (PT) increased 1.4° (p = .024). At two-year follow-up, TK and LL had returned to preoperative values (p ≥ .346) while PT had decreased from preoperative 9.7 ± 7.6° to 7.0 ± 7.5° (p > .001). Proximal junctional angle increased from 8.4 ± 5.0° preoperatively to 12.8 ± 8.9 (p < .001). Preoperatively, Roussouly curve types were distributed equally apart from a lower rate of type 1 (12%). At final follow-up, 30% were categorised as type 3 with pelvic anteversion which is considerably higher than the normal adolescent population. Only three patients were type 1 at the final follow-up. Overall, we found a high rate of proximal junctional kyphosis (16%), PI-LL mismatch (60%) and pelvic anteversion (38%). In preoperative type 1 patients, the rate was 50%, 82% and 64%, respectively. ConclusionWe found that immediate postoperative changes in lordosis and kyphosis were reversed at final follow-up and found evidence of proximal junctional kyphosation and pelvic anteversion as the main compensatory mechanisms. Poor sagittal alignment was frequent in type 1 curves, and surgical treatment may need to be individualized according to the sagittal profile. Level of EvidenceIII

Fifteen Years and 2530 Patients: The Evolution of Instrumentation, Surgical Strategies, and Outcomes in Adolescent Idiopathic Scoliosis in a Single Institution

Over the past decade, the surgical treatment of adolescent idiopathic scoliosis (AIS) has established new techniques to reduce curve severity and shifted to include the regular use of pedicle screws. Few studies have focused on this evolving trend in AIS correction surgery. In this study, we investigated how the operative approach, instrumentation, and surgical techniques have changed over the past 15 years and to quantify the related improvements in AIS surgical treatment. This is a retrospective review of a prospective AIS registry in a single center. Patient data were reviewed from January 2001 to December 2015. The age and surgical case distribution were recorded for each year. Trends in classification use, instrumentation types, levels of fusion, and surgical approaches were analyzed by year. The major Cobb angles and correction rates were compared between different instrumentations and surgical approaches. A total of 2530 patients with AIS (83.0% female) were included, with a mean age of 15.14 years. Most patients underwent surgery at 14 years of age (473 patients, 18.7%), followed by 15 years of age (468 patients, 18.5%). In our center, the classification of patients with AIS shifted from the King classification to the Lenke classification in 2005. The major baseline Cobb angle of the entire cohort averaged 50.99° and this mean Cobb angle decreased to 14.41° after surgery. The correction rates for the first 3 years (2001-2003) were less than 70%, whereas the correction rates for the rest of the years were all greater than 70%. In addition, significantly higher correction rates were observed in patients with Cobb angles <90° (72.93% vs. 55.61%, P < 0.001). A total of 218 anterior-only surgeries and 109 combined anteroposterior surgeries were performed; the remaining 2205 surgeries were performed with a posterior-only approach. The use of anterior-only and anteroposterior approaches trended to decrease after 2005. The correction rate of anterior-only approaches was significantly greater than posterior-only and anteroposterior approaches (77.86%, 72.51%, and 59.37%, respectively). In patients corrected with a posterior-only approach, the screw-hook hybrid construct was used in 342 patients, whereas the all-pedicle-screw construct was used in 1835 patients. The shift from hybrid to all-screw construct occurred in 2006. In patients with thoracic AIS, the correction rate was significantly higher in the all-screw group (73.26% vs. 67.76%; P < 0.001). Consistent improvement of major curve correction has been achieved by the spine community over 15 years. After stabilized coronal correction and fewer fusion levels, the next steps in this evolution are the restoration of sagittal profiles, especially the hypokyphosis seen in patients with Lenke 1, the posterior minimally invasive approach, and a fast-track return to activity.

Lumbar lordosis does not correlate with pelvic incidence in the cases with the lordosis apex located at L3 or above.

To test the hypothesis that the relationship between PI and L1-S1 lumbar lordosis (LL) is always positive, even in cases with different lumbar sagittal profiles. Standing whole-spine sagittal alignment was measured with EOS system in 100 healthy adults (46 men, 54 women, mean age 40.9years). The apex of lumbar lordosis was defined as the most anterior lumbar vertebra or intervertebral disk from the gravity line determined by a force plate measurement. Subjects were stratified into three groups: the upper group with an apex between L1 and L3 (UppA, n = 19), the middle group with an apex from L3/4 to L4/5 (MidA, n = 67), and the lower group with an apex at L5 or below (LowA, n = 14). PI, PT, SS, thoracic kyphosis (TK), LL, SVA, T1 pelvic angle, and knee flexion angle were compared between the groups. The correlation between LL and PI in each group was also compared. PI and SS differed significantly between the three groups, and LL was significantly different between LowA and MidA and UppA. TK and KF did not differ significantly between groups. LL and PI were significantly positively correlated in the MidA and LowA groups, but not in the UppA group. Contrary to the hypothesis, the correlation coefficient between PI and LL was not significant in the cases with apex above L3, suggesting that the relationship between PI and LL is not always constant, and whole sagittal alignment should be taken into account. These slides can be retrieved under Electronic Supplementary Material.

Association Between Lumbar Spinal Degeneration and Anatomic Pelvic Parameters.

Retrospective cohort study. The objective was to prove the association between anatomic pelvis parameters and specific types of lumbar spinal degeneration. Different spinopelvic sagittal profile types are suggested to be associated with specific degenerative lumbar spine pathologies. Because pelvic morphology plays a key role defining the spinal shape as well as its load and function it thereby potentially predisposes the development of spinal degeneration. Patients with symptomatic lumbar spinal degeneration who were surgically treated in 2 spine departments from March 2011 until August 2016 were included in this retrospective analysis. Single-level degenerative pathologies were classified as lumbar disc herniation (LDH), degenerative disc disease (DDD), lumbar spinal stenosis (LSS), and degenerative spondylolisthesis (DSPL). The constant anatomic pelvic parameters pelvic incidence (PI), pelvic radius (PR), and sacral table angle (STA) were assessed in lateral radiographs of the lumbar spine and compared between the pathologies. In total, 249 patients were assigned to the LDH (n=73), DDD (n=67), LSS (n=42), and DSPL (n=67) groups. Group comparisons revealed significant differences in the anatomic pelvic parameters PR (LDH, 139.5±10.8 mm; DDD, 135.9±14.0 mm; LSS, 127.8±14.3 mm; DSPL, 135.8±12.7 mm; P<0.001), PI (LDH, 53.1±10.0 degrees; DDD, 50.0±9.9 degrees; LSS, 54.5±9.6 degrees; DSPL, 57.1±10.8 degrees; P=0.001), and STA (LDH, 95.3±12.7 degrees; DDD, 105.4±9.0 degrees; LSS, 105.9±11.5 degrees; DSPL, 98.6±9.5 degrees; P<0.001). Post hoc tests indicated significant differences between the PR of the LSS group and that of all other subgroups (P<0.012), the PI of the DDD group and that of DSPL (P<0.001), and the STA of the LDH/DSPL groups and that of the LSS/DDD group (P<0.005). We found all the constant anatomic parameters to be specific for distinct types of degeneration, suggesting pelvis shape is a predisposing factor for their development. Level III.

Does the preoperative lumbar sagittal profile affect the selection of osteotomy level in pedicle subtraction osteotomy for thoracolumbar kyphosis secondary to ankylosing spondylitis?

ObjectiveTo investigate the different preoperative lumbar sagittal profiles of ankylosing spondylitis (AS) patients and the selection of osteotomy level for one-level pedicle subtraction osteotomy (PSO) for the correction of thoracolumbar kyphosis. Patients and methodsSeventy-one consecutive AS patients with an average age of 35.3 years and a mean follow-up time of 35.9 months who underwent one-level PSO for thoracolumbar kyphosis were divided into 2 groups based on their preoperative lumbar sagittal profiles as follows: group A, lordotic lumbar sagittal profiles; and group B, kyphotic lumbar sagittal profiles. The following radiological parameters were measured and compared: chin-brow vertical angle (CBVA), global kyphosis (GK), thoracic kyphosis (TK), lumbar lordosis (LL), sagittal vertical axis (SVA), pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS). Clinical evaluation included Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS). Perioperative and mid-term complications were reviewed. ResultsThere were 28 patients in group A and 43 in group B. The preoperative LL was −21.0° in group A and 2.3° in group B (P < 0.05). The preoperative SVA was 122.5 mm in group A and 184.3 mm in group B (P < 0.05). All the patients in group A (100%) underwent PSO at L1/L2, while 90% of group B patients underwent PSO at L2/L3, with no significant difference of postoperative GK, LL and SVA between the 2 groups (P > 0.05). No obvious loss of correction was observed in either group at the final follow-up. The correction of LL and SVA showed a strong but not statistically significant increasing trend as the PSO level descended from L1 to L3 (P > 0.05). The postoperative ODI was significantly lower in patients underwent PSO at L1 or L2 (P < 0.05). ConclusionsPatients in group B had significantly worse preoperative sagittal alignments compared to group A. The distribution of osteotomy levels varied between the 2 groups due to the different lumbar profiles; however, satisfactory correction was achieved in both groups. The preoperative lumbar profiles need to be considered in selecting the optimal osteotomy level. Patients with kyphotic lumbar profiles are suitable candidates for PSO at L2/L3, while L1/L2 PSO is appropriate for patients with lordotic lumbar profiles.

Surgical Outcomes of Single-Level Transforaminal Lumbar Interbody Fusion for Degenerative Spondylolisthesis With and Without Kyphotic Alignment

We sought to investigate the impact of single-level transforaminal lumbar interbody fusion (TLIF) on lumbar sagittal profile in degenerative spondylosis (DS) patients with or without kyphotic alignment, as well as compare radiologic and clinical outcomes based on preoperative sagittal alignment. DS with a kyphotic alignment at an involved segment constitutes a distinct subgroup. However, previous studies concerning surgical outcomes often lump all patients together without focusing on this distinct subgroup. This study reviewed a consecutive series of patients who received single-level TLIF for DS between 2009 and 2016. They were assigned to Groups K and L. All patients were followed up for >2 years. Then demographics and radiographic and clinical outcomes were compared between the groups. There were 19 and 115 patients in Group K and Group L, respectively. Compared with Group L, Group K was characterized by loss of lumbar lordosis and anterior shifting of L1 axis S1 distance. After surgery, lumbar lordosis and L1 axis S1 distance was significantly improved in Group K, while no significant change occurred in group L. The mean reduction rate was significantly higher in Group K, which had less slippage after surgery, but the differences in slip angle, anterior disk height, and posterior disk height were not significant. The preoperative Oswestry Disability Index and visual analog scale for back pain scores were significantly higher in Group K, while no differences were found in postoperative evaluation. Despite effective changes radiographic parameters and clinical outcomes, our findings suggest that the 2 groups behave differently in response to single-level TLIF procedure. Reconstruction of lumbar sagittal profile can be achieved in DS with a kyphotic alignment after surgery.