scholarly journals The correlations between the anchor density and the curve correction of adolescent idiopathic scoliosis surgery

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Yu-Cheng Yeh ◽  
Chi-Chien Niu ◽  
Lih-Huei Chen ◽  
Wen-Jer Chen ◽  
Po-Liang Lai
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Thoracic Kyphosis ◽  
Three Dimensional ◽  
High Density ◽  
Scoliosis Surgery ◽  
Low Density ◽  
Curve Correction ◽  
Kyphosis Correction ◽  
Positive Correlations

Abstract Background The optimal anchor density in adolescent idiopathic scoliosis (AIS) surgery to achieve good curve correction remains unclear. The purpose of the study is to analyze the correlations between three-dimensional curve correction and anchor density in the pedicle screw-based posterior fusion of AIS. Methods One hundred and twenty-seven AIS patients receiving primary posterior fusion with pedicle screw instrumentation were retrospectively reviewed. Anchor density (AD) was defined as the screws number per fused spinal segment. The correlations between three-dimensional curve correction radiographic parameters and anchor density were analyzed with subgroup analysis based on different curve types, curve magnitudes, and curve flexibilities. The differences of curve correction parameters between the low-density (AD ≤1.4), middle-density (1.4 < AD ≤1.7) and high-density (AD > 1.7) groups were also calculated. Independent t-test, analysis of variance (ANOVA), and Pearson’s correlation coefficient were used for statistical analysis. Results There were no correlations between the anchor density and the coronal curve correction or apical vertebral rotation (AVR) correction. In the sagittal plane, mild positive correlations existed between anchor density and thoracic kyphosis correction in all patients (r = 0.27, p = 0.002). Subgroup analysis revealed similar mild positive correlations in Lenke 1 (r = 0.31, p = 0.02), Lenke 1–3 (r = 0.27, p = 0.01), small curves (40°-60°, r = 0.38, p <  0.001), and flexible curves (flexibility > 40%, r = 0.34, p = 0.01). There were no differences between low-density (mean 1.31), middle-density (mean 1.55), and high-density (mean 1.83) in terms of coronal or axial curve correction parameters. Low-density group has longer fused level (mean difference 2.14, p = 0.001) and smaller thoracic kyphosis correction (mean difference 9.25°, p = 0.004) than high-density group. Conclusion In our study, the anchor density was not related to coronal or axial curve corrections. Mild positive correlations with anchor density were found in thoracic kyphosis correction, especially in patients with smaller and flexible curves. Low anchor density with longer fusion level achieves similar curve corrections with middle or high anchor density in adolescent idiopathic scoliosis surgery.

scholarly journals Patient-specific rods for thoracic kyphosis correction in adolescent idiopathic scoliosis surgery: Preliminary results

2020 ◽  
Vol 106 (1) ◽  
pp. 159-165 ◽  
Author(s):  
Federico Solla ◽  
Jean-Luc Clément ◽  
Vincent Cunin ◽  
Carlo M. Bertoncelli ◽  
Vincent Fière ◽  
...  
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Thoracic Kyphosis ◽  
Patient Specific ◽  
Scoliosis Surgery ◽  
Preliminary Results ◽  
Kyphosis Correction

scholarly journals Specific sagittal alignment patterns are already present in mild adolescent idiopathic scoliosis

2021 ◽  
Author(s):  
Tom P. C. Schlösser ◽  
René M. Castelein ◽  
Pierre Grobost ◽  
Suken A. Shah ◽  
Kariman Abelin-Genevois
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Inflection Point ◽  
Thoracic Kyphosis ◽  
Sagittal Alignment ◽  
Three Dimensional ◽  
Sagittal Profile ◽  
Thoracolumbar Kyphosis ◽  
C7 Slope ◽  
Sagittal Malalignment

Abstract Purpose The complex three-dimensional spinal deformity in AIS consists of rotated, lordotic apical areas and neutral junctional zones that modify the spine’s sagittal profile. Recently, three specific patterns of thoracic sagittal ‘malalignment’ were described for severe AIS. The aim of this study is to define whether specific patterns of pathological sagittal alignment are already present in mild AIS. Methods Lateral spinal radiographs of 192 mild (10°–20°) and 253 severe (> 45°) AIS patients and 156 controls were derived from an international consortium. Kyphosis characteristics (T4–T12 thoracic kyphosis, T10–L2 angle, C7 slope, location of the apex of kyphosis and of the inflection point) and sagittal curve types according to Abelin-Genevois were systematically compared between the three cohorts. Results Even in mild thoracic AIS, already 49% of the curves presented sagittal malalignment, mostly thoracic hypokyphosis, whereas only 13% of the (thoraco) lumbar curves and 6% of the nonscoliosis adolescents were hypokyphotic. In severe AIS, 63% had a sagittal malalignment. Hypokyphosis + thoracolumbar kyphosis occurred more frequently in high-PI and primary lumbar curves, whereas cervicothoracic kyphosis occurred more in double thoracic curves. Conclusions Pathological sagittal patterns are often already present in curves 10°–20°, whereas those are rare in non-scoliotic adolescents. This suggests that sagittal ‘malalignment’ patterns are an integral part of the early pathogenesis of AIS.

scholarly journals Predictability of Coronal Curve Flexibility in Postoperative Curve Correction in Adolescent Idiopathic Scoliosis: The Effect of the Sagittal Profile

2019 ◽  
Vol 10 (3) ◽  
pp. 303-311 ◽  
Author(s):  
Søren Ohrt-Nissen ◽  
Hideki Shigematsu ◽  
Jason Pui Yin Cheung ◽  
Keith D. K. Luk ◽  
Dino Samartzis
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Cobb Angle ◽  
Thoracic Kyphosis ◽  
Clinical Decision Making ◽  
Sagittal Profile ◽  
Curve Correction ◽  
Sagittal Vertical Axis ◽  
Flexibility Index

Study Design: Retrospective cohort study. Objectives: To assess how the thoracic kyphosis affects the ability of the fulcrum bending radiograph (FBR) to predict the coronal thoracic curve correction. Methods: A retrospective study of prospectively collected data was conducted of 107 consecutive patients with thoracic adolescent idiopathic scoliosis (AIS) treated with a standard screw-fixation protocol. Radiographic variables were assessed preoperatively and at 2-year follow-up. Curve flexibility was determined based on the FBR and the Fulcrum Bending Flexibility Index (FBCI). Radiographic variables included preoperative Cobb angle, T5-T12 kyphosis, T12-S1 lordosis, sagittal vertical axis, list, T1-T12 length, truncal shift, and radiographic shoulder height. Patients were also categorized as hypo-, normo-, or hyperkyphotic. Results: Based on multivariate modeling, an increase in FBR Cobb angle and thoracic kyphosis were significantly associated with an increase in FBCI (increased mismatch between the FBR and postoperative Cobb angles) at 2-year follow-up ( P < 0.001). In patients with hyperkyphosis, a longer instrumented length existed despite similar curve size and shorter curve length than the hypo- and normokyphotic groups. Based on these findings, we developed a new predictive postoperative curve correction index, known as the Multiprofile Flexibility Index (MFI). Conclusions: Our results show that an increase in preoperative thoracic kyphosis is associated with an increased difference between the preoperative coronal curve flexibility and the postoperative coronal curve correction. Our findings broaden the understanding of curve flexibility and indicate that selection of fusion levels may need to take into consideration the sagittal profile to improve clinical decision making and optimize outcome.

scholarly journals Higher pedicle screw density does not improve curve correction in Lenke 2 adolescent idiopathic scoliosis

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Timothy J. Skalak ◽  
Joel Gagnier ◽  
Michelle S. Caird ◽  
Frances A. Farley ◽  
Ying Li
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Thoracic Kyphosis ◽  
Curve Correction ◽  
Major Curve ◽  
Curve Magnitude ◽  
Screw Density ◽  
Implant Density ◽  
Lenke 2

Abstract Purpose Higher pedicle screw density posterior spinal fusion (PSF) constructs have not been shown to result in improved curve correction in Lenke 1 and 5 adolescent idiopathic scoliosis (AIS) but do increase cost. The purpose of this study questioned whether higher screw density constructs improved curve correction and maintenance of correction in Lenke 2 AIS. Secondary goals were to identify predictive factors for correction and postoperative magnitude of curves in Lenke 2 AIS. Methods We identified patients 11 to 17 years old who underwent primary PSF for Lenke 2 AIS between 2007 and 2017 who had minimum follow-up of 2 years. Demographic and radiographic data were collected to perform regression and elimination analysis. Results Thirty patients (21 females, 9 males) were analyzed. Average age and SD at time of surgery was 14.0 ± 1.8 years (range, 11–17 years), and median follow-up was 2.8 years (IQR 2.1–4.0 years). Implant density did not predict final postoperative curve magnitude. Predictors of final postoperative curve magnitude were sex and preoperative curve magnitude. Predictors of percentage of correction of major curve were sex and age at the time of surgery. Predictors of final postoperative thoracic kyphosis were sex and percent flexibility preop. Females had lower final postoperative major curve magnitude, a higher percent curve correction, and lower postoperative thoracic kyphosis. Conclusions Increased implant density is not predictive of postoperative curve magnitude in Lenke 2 AIS. Predictors of postoperative curve magnitude are sex and preoperative curve magnitude. Level of evidence Level III, retrospective observational

scholarly journals Changes in Thoracic Torsion in Adolescent Idiopathic Scoliosis Patients Within a 2-year Postoperative Period

2021 ◽  
Author(s):  
yonggang wang ◽  
Dongmin Wang ◽  
Xuewen Kang ◽  
Zhanjun Ma ◽  
Yingping Ma ◽  
...  
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Cobb Angle ◽  
Postoperative Period ◽  
Structural Model ◽  
Three Dimensional ◽  
Posterior Spinal Fusion ◽  
Scoliosis Surgery ◽  
Thoracic Cavity ◽  
Radiological Parameters

Abstract Background: Scoliosis can cause deformities of the rib cage. The three-dimensional (3D) shape of the rib-vertebral-sternal complex matches that of the thoracic cavity and is visualized as an elastic structural model that is approximately cubic in shape. This study was performed to evaluate the changes in thoracic torsion by measuring radiological parameters.Methods: Forty-four patients with adolescent idiopathic scoliosis (AIS) with a main right thoracic curvature underwent posterior spinal fusion (PSF), and radiological parameters of the spine and thorax were evaluated. Results: The correction of preoperative, immediately postoperative, and 2-year postoperative MT-Cobb angles were 64% and 66%. The correction of T1–T12 heights were 10% and 12%. The correction of RVAD was 59% immediately postoperatively and 52% at 2 year postoperatively. The correction of RH was 59% immediately postoperatively and 52% at 2 year postoperatively. The correction of AVB-R was 23% immediately postoperatively and 25% at 2 year postoperatively. From the above results, all radiological parameters were significantly different immediately and at 2 year postoperatively compared to preoperatively (p < 0.001). There were significant correlations between MT-Cobb angle and T1–T12 height (p < 0.001), RVAD (p < 0.001), RH (p < 0.001), and AVB-R (p < 0.001).Conclusion: Most cases of mild and moderate scoliosis surgery also includes the correction of thoracic torsion. PSF appears to be effective at correcting scoliosis, and the correction of thoracic torsion also plays an important role.

scholarly journals “Higher Pedicle Screw Density Does Not Result in Improved Curve Correction in Lenke 2 Adolescent Idiopathic Scoliosis”

2021 ◽  
Author(s):  
Timothy Skalak ◽  
Joel Gagnier ◽  
Michelle S. Caird ◽  
Frances A. Farley ◽  
Ying Li
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Thoracic Kyphosis ◽  
Curve Correction ◽  
Major Curve ◽  
Curve Magnitude ◽  
Screw Density ◽  
Implant Density ◽  
Lenke 2

Abstract Purpose: Higher pedicle screw density posterior spinal fusion (PSF) constructs have not been shown to result in improved curve correction in Lenke 1 and 5 adolescent idiopathic scoliosis (AIS) but do increase cost. The purpose of this study questioned whether higher screw density constructs improved curve correction and maintenance of correction in Lenke 2 AIS. Secondary goals were to identify predictive factors for correction and postoperative magnitude of curves in Lenke 2 AIS. Methods: We identified patients 11 to 17 years old who underwent primary PSF for Lenke 2 AIS between 2007 and 2017 who had minimum follow up of 2 years. Demographic and radiographic data were collected to perform regression and elimination analysis. Results: Thirty patients (21 Female, 9 male) were analyzed. Average age and SD at time of surgery was 14.0 ± 1.8 years (range, 11-17 years) and median follow-up was 2.8 years (IQR 2.1-4.0 years). Implant density did not predict final postoperative curve magnitude. Predictors of final postoperative curve magnitude were sex and preoperative curve magnitude. Predictors of percentage of correction of major curve were sex and age at the time of surgery. Predictors of final postoperative thoracic kyphosis were sex and percent flexibility preop. Females had lower final postoperative major curve magnitude, a higher percent curve correction, and lower postoperative thoracic kyphosis.Conclusions: Increased implant density is not predictive of postoperative curve magnitude in Lenke 2 AIS. Predictors of postoperative curve magnitude are sex and preoperative curve magnitude.Level of Evidence: Level III Retrospective Observational

scholarly journals Improved restoration of thoracic kyphosis using a rod construct with differentiated rigidity in the surgical treatment of adolescent idiopathic scoliosis

2017 ◽  
Vol 43 (4) ◽  
pp. E6 ◽  
Author(s):  
Søren Ohrt-Nissen ◽  
Casper Dragsted ◽  
Benny Dahl ◽  
John A. I. Ferguson ◽  
Martin Gehrchen
Keyword(s):  
Adolescent Idiopathic Scoliosis ◽  
Idiopathic Scoliosis ◽  
Thoracic Kyphosis ◽  
Sagittal Alignment ◽  
Group Versus ◽  
Secondary Outcome ◽  
Curve Correction ◽  
Caudal Portion ◽  
Significant Difference ◽  
The Mean

OBJECTIVEThe objective of this study was to compare postoperative sagittal alignment among 3 rod constructs with different rigidity profiles.METHODSThis was a dual-center retrospective cohort study involving 2 consecutive cohorts in which patients were surgically treated for adolescent idiopathic scoliosis. Lenke Type 5 curves were excluded. Patients were operated on with all–pedicle screw instrumentation using 3 different rod constructs. The first group was operated on using a hybrid construct (HC) consisting of a normal circular rod on the convex side and a beam-like rod (BR) on the concave side. The second group was operated on with a standard construct (SC) using bilateral BRs in the full length of the fusion. The third group was operated on with a modified construct (MC). The modified rods have a beam-like shape in the caudal portion, but in the cranial 2 or 3 fusion levels the rod transitions to a circular shape with a smaller anteroposterior diameter. Radiographs were analyzed preoperatively and at the first postoperative follow-up (range 1–8 weeks). The primary outcome was pre- to postoperative change in thoracic kyphosis (TK), and the secondary outcome was the ability to achieve postoperative TK within the normal range.RESULTSThe HC, SC, and MC groups included 23, 70, and 46 patients, respectively. The 3 groups did not differ significantly in preoperative demographic or radiographic parameters. The mean ± standard deviation of the preoperative main curve was 60.7° ± 12.6°, and the mean of curve correction was 62.9% ± 10.4% with no significant difference among groups (p ≥ 0.680). The groups did not differ significantly in coronal balance or proximal or thoracolumbar curve correction (p ≥ 0.189). Mean postoperative TK was 23.1° ± 6.3°, 19.6° ± 7.6°, and 23.4° ± 6.9° in the HC, SC and MC groups, respectively (p = 0.013), and the mean change in TK was −3.5° ± 11.3°, −7.1° ± 11.6°, and 0.1° ± 10.9°, respectively (p = 0.005). The MC group had significantly higher postoperative TK and less loss of TK compared with the SC group (p ≤ 0.018). Postoperative TK ≤ 10° was found in 12 patients (17%) in the SC group, 1 patient (5%) in the HC group, and 1 patient (2%) in the MC group (p = 0.021). There were no differences in proximal alignment, thoracolumbar alignment, or sagittal vertical axis (p ≥ 0.249). Lumbar lordosis was 58.9° ± 11.2° in the HC group versus 52.0° ± 1.3° and 55.0° ± 11.0° and the SC and MC groups, respectively (p = 0.040).CONCLUSIONSIn the 3 rod constructs with different rigidity profiles, significantly better restoration of kyphosis was achieved with the use of bilateral modified rods compared with bilateral standard rods. In the MC and HC groups, the rate of severe postoperative hypokyphosis was significantly lower than in the SC group. This is the first study to describe the clinical use of a rod with a reduced proximal diameter and show marked radiographic improvement in sagittal alignment.

Sign in / Sign up

Export Citation Format

Share Document