Cross-validation of ultrasound imaging in adolescent idiopathic scoliosis

Abstract Purpose Adolescent idiopathic scoliosis (AIS) patients are exposed to 9–10 times more radiation and a fivefold increased lifetime cancer risk. Radiation-free imaging alternatives are needed. Ultrasound imaging of spinal curvature was shown to be accurate, however, systematically underestimating the Cobb angle. The purpose of this study is to create and cross-validate an equation that calculates the expected Cobb angle using ultrasound spinal measurements of AIS patients. Methods Seventy AIS patients with upright radiography and spinal ultrasound were split randomly in a 4:1 ratio to the equation creation (n = 54) or validation (n = 16) group. Ultrasound angles based on the spinous processes shadows were measured automatically by the ultrasound system (Scolioscan, Telefield, Hong Kong). For thoracic and lumbar curves separately, the equation: expected Cobb angle = regression coefficient × ultrasound angle, was created and subsequently cross-validated in the validation group. Results Linear regression analysis between ultrasound angles and radiographic Cobb angles (thoracic: R2 = 0.968, lumbar: R2 = 0.923, p < 0.001) in the creation group resulted in the equations: thoracic Cobb angle = 1.43 × ultrasound angle and lumbar Cobb angle = 1.23 × ultrasound angle. With these equations, expected Cobb angles in the validation group were calculated and showed an excellent correlation with the radiographic Cobb angles (thoracic: R2 = 0.959, lumbar: R2 = 0.936, p < 0.001). The mean absolute differences were 6.5°–7.3°. Bland–Altman plots showed good accuracy and no proportional bias. Conclusion The equations from ultrasound measurements to Cobb angles were valid and accurate. This supports the implementation of ultrasound imaging, possibly leading to less frequent radiography and reducing ionizing radiation in AIS patients.

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Prediction of height increment using preoperative radiological parameters following selective thoracic fusion with alternate-level pedicle screw construct in Lenke 1 and 2 adolescent idiopathic scoliosis patients

Journal of Orthopaedic Surgery ◽

10.1177/2309499016684431 ◽

2017 ◽

Vol 25 (1) ◽

pp. 230949901668443 ◽

Cited By ~ 2

Author(s):

Kwan Mun Keong ◽

Izzuddin Aziz ◽

Chris Chan Yin Wei

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Cobb Angle ◽

Pedicle Screw ◽

Linear Regression Analysis ◽

Multivariable Analysis ◽

Height Increment ◽

Independent Observer ◽

Radiological Parameters ◽

Scoliosis Correction

Purpose: This study aims to derive a formula to predict post-operative height increment in Lenke 1 and Lenke 2 adolescent idiopathic scoliosis (AIS) patients using preoperative radiological parameters. Methods: This study involved 70 consecutive Lenke 1 and 2 AIS patients who underwent scoliosis correction with alternate-level pedicle screw instrumentation. Preoperative parameters that were measured included main thoracic (MT) Cobb angle, proximal thoracic (PT) Cobb angle, lumbar Cobb angle as well as thoracic kyphosis. Side-bending flexibility (SBF) and fulcrum-bending flexibility (FBF) were derived from the measurements. Preoperative height and post-operative height increment was measured by an independent observer using a standardized method. Results: MT Cobb angle and FB Cobb angle were significant predictors ( p < 0.001) of height increment from multiple linear regression analysis ( R = 0.784, R2 = 0.615). PT Cobb angle, lumbar, SB Cobb angle, preoperative height and number of fused segment were not significant predictors for the height increment based on the multivariable analysis. Increase in post-operative height could be calculated by the formula: Increase in height (cm) = (0.09 × preoperative MT Cobb angle) – (0.04 x FB Cobb angle) – 0.5. Conclusion: The proposed formula of increase in height (cm) = (0.09 × preoperative MT Cobb angle) − (0.04 × FB Cobb angle) – 0.5 could predict post-operative height gain to within 5 mm accuracy in 51% of patients, within 10 mm in 70% and within 15 mm in 86% of patients.

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Upper instrumented vertebra to the right of the lowest instrumented vertebra as a predictor of an increase in the main thoracic curve after selective posterior fusion for the thoracolumbar/lumbar curve in Lenke type 5C adolescent idiopathic scoliosis: multicenter study on the relationship between fusion area and surgical outcome

Journal of Neurosurgery Spine ◽

10.3171/2019.5.spine181469 ◽

2019 ◽

Vol 31 (6) ◽

pp. 857-864 ◽

Cited By ~ 1

Author(s):

Hiroki Oba ◽

Jun Takahashi ◽

Sho Kobayashi ◽

Tetsuro Ohba ◽

Shota Ikegami ◽

...

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Cobb Angle ◽

Posterior Fusion ◽

Main Thoracic ◽

Lowest Instrumented Vertebra ◽

Line Tilt ◽

The Right ◽

Upper Instrumented Vertebra

OBJECTIVEUnfused main thoracic (MT) curvatures occasionally increase after selective thoracolumbar/lumbar (TL/L) fusion. This study sought to identify the predictors of an unacceptable increase in MT curve (UIMT) after selective posterior fusion (SPF) of the TL/L curve in patients with Lenke type 5C adolescent idiopathic scoliosis (AIS).METHODSForty-eight consecutive patients (44 females and 4 males, mean age 15.7 ± 2.5 years, range 13–24 years) with Lenke type 5C AIS who underwent SPF of the TL/L curve were analyzed. The novel “Shinshu line” (S-line) was defined as a line connecting the centers of the concave-side pedicles of the upper instrumented vertebra (UIV) and lowest instrumented vertebra (LIV) on preoperative radiographs. The authors established an S-line tilt to the right as S-line positive (S-line+, i.e., the UIV being to the right of the LIV) and compared S-line+ and S-line− groups for thoracic apical vertebral translation (T-AVT) and MT Cobb angle preoperatively, early postoperatively, and at final follow-up. The predictors for T-AVT > 20 mm at final follow-up were evaluated as well. T-AVT > 20 mm was defined as a UIMT.RESULTSAmong the 48 consecutively treated patients, 26 were S-line+ and 22 were S-line−. At preoperative, early postoperative, and final follow-up a minimum of 2 years later, the mean T-AVT was 12.8 mm (range −9.3 to 32.8 mm), 19.6 mm (range −13.0 to 41.0 mm), and 22.8 mm (range −1.9 to 68.7 mm) in the S-line+ group, and 10.8 mm (range −5.1 to 27.3 mm), 16.2 mm (range −11.7 to 42.1 mm), and 11.0 mm (range −6.3 to 26.9 mm) in the S-line− group, respectively. T-AVT in S-line+ patients was significantly larger than that in S-line− patients at the final follow-up. Multivariate analysis revealed S-line+ (odds ratio [OR] 23.8, p = 0.003) and preoperative MT Cobb angle (OR 7.9, p = 0.001) to be predictors of a UIMT.CONCLUSIONSS-line+ was defined as the UIV being to the right of the LIV. T-AVT in the S-line+ group was significantly larger than in the S-line− group at the final follow-up. S-line+ status and larger preoperative MT Cobb angle were independent predictors of a UIMT after SPF for the TL/L curve in patients with Lenke type 5C AIS. Surgeons should consider changing the UIV and/or LIV in patients exhibiting S-line+ during preoperative planning to avoid a possible increase in MT curve and revision surgery.

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Clinical predictive model of lumbar curve Cobb angle below selective fusion for thoracic adolescent idiopathic scoliosis: a longitudinal multicenter descriptive study

European Journal of Orthopaedic Surgery & Traumatology ◽

10.1007/s00590-021-03054-5 ◽

2021 ◽

Author(s):

Federico Solla ◽

Walid Lakhal ◽

Christian Morin ◽

Jerome Sales de Gauzy ◽

Gaby Kreichati ◽

...

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Cobb Angle ◽

Predictive Model ◽

Descriptive Study ◽

Lumbar Curve ◽

Selective Fusion ◽

Clinical Predictive Model

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Sagittal profile modifications in hybrid versus all screw technique in adolescent idiopathic scoliosis

Scientific Reports ◽

10.1038/s41598-020-79523-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Laura Scaramuzzo ◽

Antonino Zagra ◽

Giuseppe Barone ◽

Stefano Muzzi ◽

Leone Minoia ◽

...

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Cobb Angle ◽

Thoracic Kyphosis ◽

Sagittal Alignment ◽

Vertical Axis ◽

Sagittal Profile ◽

Sacral Slope ◽

Sagittal Vertical Axis ◽

Lenke Classification

AbstractAim of the study was to evaluate sagittal parameters modifications, with particular interest in thoracic kyphosis, in patients affected by adolescent idiopathic scoliosis (AIS) comparing hybrid and all-screws technique. From June 2010 to September 2018, 145 patients were enrolled. Evaluation included: Lenke classification, Risser scale, coronal Cobb angle, thoracic kyphosis (TK), lumbar lordosis (LL), sagittal vertical axis (SVA), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS). Patients were divided in two groups (1 all-screws and 2 hybrid); a further division, in both groups, was done considering preoperative TK values. Descriptive and inferential statistical analysis was conducted. 99 patients were in group 1, 46 in group 2 (mean follow-up 3.7 years). Patients with a normo-kyphotic profile developed a little variation in TK (Δ pre–post = 2.4° versus − 2.0° respectively). Hyper-kyphotic subgroups had a tendency of restoring a good sagittal alignment. Hypo-kyphotic subgroups, patients treated with all-screw implants developed a higher increase in TK mean Cobb angle (Δ pre–post = 10°) than the hybrid subgroup (Δ pre–post = 5.4°) (p = 0.01). All-screws group showed better results in restoring sagittal alignment in all subgroups compared to hybrid groups, especially in hypo-TK subgroup, with the important advantage to give better correction on coronal plane.

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Comparison of Changes in SRS-22 Values with Improvement in Cobb Angles after Posterior Fusion Surgery in Adolescent Idiopathic Scoliosis

Zeitschrift für Orthopädie und Unfallchirurgie ◽

10.1055/a-1401-0477 ◽

2021 ◽

Author(s):

Kadir Gem ◽

Sertan Hancioglu ◽

Abdulkadir Bilgiç ◽

Serkan Erkan

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Cobb Angle ◽

Posterior Instrumentation ◽

Research Society ◽

Posterior Fusion ◽

Improvement Rate ◽

Scoliosis Research Society ◽

Correction Rate ◽

Group B

Abstract Introduction The purpose of this study was to evaluate the relationship between the correction rate in Cobb angle and the improvement in quality of life profile in terms of Scoliosis Research Society (SRS)-22 values. Patients and Methods Between January 2007 and December 2013, posterior instrumentation and fusion was performed to 30 patients with adolescent idiopathic scoliosis (AIS). Patients were grouped according to their improvement rate in Cobb angles after surgery. Patients with an improvement rate of > 80% were grouped as Group A; those with an improvement rate of > 60% and ≤ 80% as Group B and those with an improvement rate of ≤ 60% were grouped as Group C. The SRS-22 questionnaire of these three groups was calculated and their relationship with the improvement in Cobb angle was evaluated. Results No statistical difference was found among the three groups in terms of pain, appearance, function, spirit, satisfaction, and SRS-22 values (all p > 0.05). Conclusion The results of this study demonstrate that the degree of correction rate does not correlate with the degree of improvement in the SRS-22 questionnaire in patients with AIS that underwent posterior fusion and instrumentation.

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The effect of Cobb angle correction on spinal length gain in patients with adolescent idiopathic scoliosis

Journal of Pediatric Orthopaedics B ◽

10.1097/bpb.0000000000000512 ◽

2019 ◽

Vol 28 (1) ◽

pp. 22-26

Author(s):

Hassan Ghandhari ◽

Ebrahim Ameri ◽

Mir Bahram Safari ◽

Habib Kheirabadi ◽

Hadi S. Asl ◽

...

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Cobb Angle ◽

Angle Correction ◽

Length Gain

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Concave or convex rod translation first in adolescent idiopathic scoliosis instrumentation with differential rod contouring?

Studies in Health Technology and Informatics - Research into Spinal Deformities 9 ◽

10.3233/shti210455 ◽

2021 ◽

Author(s):

X Wang ◽

CE Aubin ◽

RM Schwend

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Cobb Angle ◽

Thoracic Kyphosis ◽

Deformity Correction ◽

Vertebral Rotation ◽

Convex Side ◽

Bone Screw ◽

Apical Vertebral Rotation ◽

Clinically Significant

The objective was to assess deformity correction and bone-screw force associated respectively with concave manipulation first, convex manipulation first, and different differential rod contouring configurations. Instrumentation scenarios were computationally simulated for 10 AIS cases with mean thoracic Cobb angle (MT) of 54±8°, apical vertebral rotation (AVR) of 19±2° and thoracic kyphosis of 21±9°. Instrumentations with major correction maneuvers using the concave side rod were first simulated; instrumentations with major correction maneuvers using the convex side rod were then simulated. Simulated correction maneuvers were concave/convex rod translation followed by apical vertebral derotation and then convex/concave rod translation. There were no significant differences in deformity corrections and bone-screw forces between concave rod translation first and convex rod translation first with differential rod contouring. Increasing differential rod contouring angle and concave rod diameter improved AVR correction and increased the TK and bone-screw forces; the effect on the MT Cobb angle was not clinically significant.

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Supine flexibility predicts curve progression for patients with adolescent idiopathic scoliosis undergoing underarm bracing

The Bone & Joint Journal ◽

10.1302/0301-620x.102b2.bjj-2019-0916.r1 ◽

2020 ◽

Vol 102-B (2) ◽

pp. 254-260 ◽

Cited By ~ 4

Author(s):

Jason P. Y. Cheung ◽

Prudence W. H. Cheung

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Regression Model ◽

Cobb Angle ◽

Characteristic Curve ◽

Absolute Error ◽

Curve Progression ◽

Curve Magnitude ◽

Spine Radiograph ◽

Whole Spine

Aims The aim of this study was to assess whether supine flexibility predicts the likelihood of curve progression in patients with adolescent idiopathic scoliosis (AIS) undergoing brace treatment. Methods This was a retrospective analysis of patients with AIS prescribed with an underarm brace between September 2008 to April 2013 and followed up until 18 years of age or required surgery. Patients with structural proximal curves that preclude underarm bracing, those who were lost to follow-up, and those who had poor compliance to bracing (<16 hours a day) were excluded. The major curve Cobb angle, curve type, and location were measured on the pre-brace standing posteroanterior (PA) radiograph, supine whole spine radiograph, initial in-brace standing PA radiograph, and the post-brace weaning standing PA radiograph. Validation of the previous in-brace Cobb angle regression model was performed. The outcome of curve progression post-bracing was tested using a logistic regression model. The supine flexibility cut-off for curve progression was analyzed with receiver operating characteristic curve. Results A total of 586 patients with mean age of 12.6 years (SD 1.2) remained for analysis after exclusion. The baseline Cobb angle was similar for thoracic major curves (31.6° (SD 3.8°)) and lumbar major curves (30.3° (SD 3.7°)). Curve progression was more common in the thoracic curves than lumbar curves with mean final Cobb angles of 40.5° (SD 12.5°) and 31.8° (SD 9.8°) respectively. This dataset matched the prediction model for in-brace Cobb angle with less mean absolute error in thoracic curves (0.61) as compared to lumbar curves (1.04). Reduced age and Risser stage, thoracic curves, increased pre-brace Cobb angle, and reduced correction and flexibility rates predicted increased likelihood of curve progression. Flexibility rate of more than 28% has likelihood of preventing curve progression with bracing. Conclusion Supine radiographs provide satisfactory prediction for in-brace correction and post-bracing curve magnitude. The flexibility of the curve is a guide to determine the likelihood for brace success. Cite this article: Bone Joint J 2020;102-B(2):254–260.

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PHOTOGRAMMETRY: A PROPOSAL OF OBJECTIVE ASSESSMENT OF CHEST WALL IN ADOLESCENT IDIOPATHIC SCOLIOSIS

Revista Paulista de Pediatria ◽

10.1590/1984-0462/;2019;37;2;00001 ◽

2019 ◽

Vol 37 (2) ◽

pp. 225-233

Author(s):

Anderson Sales Alexandre ◽

Evandro Fornias Sperandio ◽

Liu Chiao Yi ◽

Josy Davidson ◽

Patrícia Rios Poletto ◽

...

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Lung Function ◽

Idiopathic Scoliosis ◽

Cobb Angle ◽

Chest Wall ◽

Healthy Subjects ◽

Objective Assessment ◽

Spine Deformity ◽

Xiphoid Process ◽

Cross Sectional

ABSTRACT Objective: To evaluate the chest wall shape in patients with adolescent idiopathic scoliosis (AIS) in comparison to healthy subjects and the association between the chest wall shape with the spine deformity and lung function in patients with AIS. Methods: This cross-sectional study enrolled 30 AIS patients and 20 healthy subjects aged 11-18 years old. The Cobb angle evaluation was performed in AIS patients. The chest wall shape was assessed by the photogrammetry method, using the Postural Assessment Software (PAS). We created thoracic markers shaped as angles (A) and distances (D), as follows: A2 (right acromion/xiphoid/left acromion), A4L (angle formed between the outer point of the smallest waist circumference and its upper and lower edges on the left side), A7 (angle formed by the intersection of the tangent segments of the upper and lower scapulae angles), D1R/D1L [distance between the xiphoid process and the last false rib on the right (R) and left (L) sides], and D3 (distance between xiphoid process and anterior superior iliac spine). Results: The thoracic markers A2 and A7 were significantly higher, while the A4L and D1R/D1L were significantly reduced in the AIS group compared to the control. Moderate correlations were found between: A2 and the main and proximal thoracic Cobb angles (r=0.50, r=0.47, respectively); D1R/D1L and the main thoracic Cobb angle (r=- 0.40); and the forced expiratory volume in the first second (FEV1) and D3R (r=0.47). Conclusions: The photogrammetry method was able to detect chest wall changes in AIS patients, besides presenting correlation between Cobb angles and lung function.

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