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Purpose: Clinicians monitor scoliosis progression using radiographs during growth. Three standing positions were assessed because the arms must be elevated to visualize all vertebrae on radiographs, possibly affecting sagittal parameters. 3D Ultrasound (3DUS) is safe to assess positions without radiation, but its test-retest reliability has not been established for common radiograph positions. The aim was to determine the test-retest reliability of frontal, sagittal, and transverse measurements obtained from three positions using 3DUS imaging., Methods: Participants with AIS were recruited from a clinic in Alberta. Participants underwent 3DUS scans in habitual standing, fingers to clavicle, and hands on wall. Participants were re-scanned in the same positions 20-min following first scans. Custom software obtained measurements. Test-retest reliability (ICC 3,1 ) with standard error of measurement (SEM) was assessed by one evaluator who was blinded to the test measurement when completing retest., Results: Forty-three participants with AIS had an age, height, and weight of 15 ± 2 years, 164 ± 10 cm, and 54 ± 11 kg, respectively. Standing curve angle was 23 ± 11°. Habitual standing max curve angle, T4/T5 kyphosis, and AVR twist satisfied criteria for individual use (ICC 2,1  > 0.90). Fingers to clavicle AVR twist satisfied criteria for individual use, and all hands on wall measurements satisfied criteria for individual use (ICC > 0.90). All other parameters satisfied criteria for research use (ICC > 0.70). Range of SEM for curve angle, whole kyphosis, T4/T5 kyphosis, lordosis, and AVR twist were 3.0-4.8°, 4.0-5.1°, 3.6-5.3°, 3.9-5.6°, and 1.6-2.2°, respectively., Conclusion: 3DUS produces reliable frontal, sagittal, and transverse measurements for research use in three standing positions. Hands on wall produces reliable measurements for clinical practice., Competing Interests: Declarations. Conflict of interest: The authors declare that they have no conflict of interest. Consent to participate: Written assent was obtained from all individual participants under the age of 18 included in this study. Written parental consent was obtained from the parents of participants under the age of 18. Written consent was obtained from all individual participants 18 years old. Ethical approval: This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Health Research Ethics Board of the University of Alberta PRO00111881., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: To report the accuracy and reliability of Cobb angle (CA), axial vertebral rotation (AVR), kyphotic and lordotic angles (KA and LA) measurements on using a new 3D ultrasound (US) system., Methods: Forty participants (34 F, 6 M, aged 14.0 ± 2.3 years) were recruited. The first 20 participants were scanned by the validated US system and the new US system. The other 20 participants were scanned with the new US system only. Two raters (R1 and R2) performed the measurements: R1 has 10 years of experience in radiology but is new in ultrasound scoliosis, while R2 has 30 years of scoliosis experience. All US images were measured twice by R1, and once by R2. Forty posteroanterior and 30 lateral standing radiographs were obtained and measured once by R1. Statistical analysis consisted of mean absolute difference (MAD), intraclass correlation coefficient (ICC (2,1)), and Bland-Altman plots., Results: R1 showed excellent intra-rater and inter-rater reliability for US measurements with ICCs(2,1) ≥ 0.91. The inter-method reliability was good between the two US systems for all parameters with ICCs(2,1) ≥ 0.85 and maximum MAD of 3.4°. The new US showed good reliability and accuracy compared to radiographs for CA, AVR and KA with ICCs(2,1) ≥ 0.81 and maximum MAD of 5.8°, but poor results for LA with ICCs(2,1) of 0.27-0.35 and MADs of 14.0°-15.4°., Conclusion: The new 3D US system showed good reliability and accuracy for CA, AVR and KA measurements, but a large measurement discrepancy on LA. A new measurement method for US LA may need to investigate., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Ultrasonography for scoliosis is a novel imaging method that does not expose children with adolescent idiopathic scoliosis (AIS) to radiation. A single ultrasound scan provides 3D spinal views directly. However, measuring ultrasonograph parameters is challenging, time-consuming, and requires considerable training. This study aimed to validate a machine learning method to measure the coronal curve angle on ultrasonographs automatically., Methods: A total of 144 3D spinal ultrasonographs were extracted to train and validate a machine learning model. Among the 144 images, 70 were used for training, and 74 consisted of 144 curves for testing. Automatic coronal curve angle measurements were validated by comparing them with manual measurements performed by an experienced rater. The inter-method intraclass correlation coefficient (ICC 2,1 ), standard error of measurement (SEM), and percentage of measurements within clinical acceptance (≤ 5°) were analyzed., Results: The automatic method detected 125/144 manually measured curves. The averages of the 125 manual and automatic coronal curve angle measurements were 22.4 ± 8.0° and 22.9 ± 8.7°, respectively. Good reliability was achieved with ICC 2,1  = 0.81 and SEM = 1.4°. A total of 75% (94/125) of the measurements were within clinical acceptance. The average measurement time per ultrasonograph was 36 ± 7 s. Additionally, the algorithm displayed the predicted centers of laminae to illustrate the measurement., Conclusion: The automatic algorithm measured the coronal curve angle with moderate accuracy but good reliability. The algorithm's quick measurement time and interpretability can make ultrasound a more accessible imaging method for children with AIS. However, further improvements are needed to bring the method to clinical use., (© 2024. The Author(s).)

Purpose: To validate a fast 3D biplanar spinal radiograph reconstruction method with automatic extract curvature parameters using artificial intelligence (AI)., Methods: Three-hundred eighty paired, posteroanterior and lateral, radiographs from the EOS X-ray system of children with adolescent idiopathic scoliosis were randomly selected from the database. For the AI model development, 304 paired images were used for training; 76 pairs were employed for testing. The validation was evaluated by comparing curvature parameters, including Cobb angles (CA), apical axial vertebral rotation (AVR), kyphotic angle (T1-T12 KA), and lordotic angle (L1-L5 LA), to manual measurements from a rater with 8 years of scoliosis experience. The mean absolute differences ± standard deviation (MAD ± SD), the percentage of measurements within the clinically acceptable errors, the standard error of measurement (SEM), and the inter-method intraclass correlation coefficient ICC [2,1] were calculated. The average reconstruction speed of the 76 test images was recorded., Results: Among the 76 test images, 134 and 128 CA were exported automatically and measured manually, respectively. The MAD ± SD for CA, AVR at apex, KA, and LA were 3.3° ± 3.5°, 1.5° ± 1.5°, 3.3° ± 2.6° and 3.5° ± 2.5°, respectively, and 98% of these measurements were within the clinical acceptance errors. The SEMs and the ICC [2,1] for the compared parameters were all less than 0.7° and > 0.94, respectively. The average time to display the 3D spine and report the measurements was 5.2 ± 1.3 s., Conclusion: The developed AI algorithm could reconstruct a 3D scoliotic spine within 6 s, and the automatic curvature parameters were accurately and reliably extracted from the reconstructed images., (© 2024. The Author(s).)

Purpose: To investigate the test-retest, intra- and inter-rater reliabilities of an ultrasound (US) reflection coefficient (RC) index measured in a lumbar vertebra to reflect bone strength on children with AIS., Methods: Fifty-eight participants (47F; 11M) were scanned by an US imager in standing position. Twenty-four were scanned twice for a test-retest study. The RC index measures the US signal reflected from L5 to indicate bone strength. Five measurements were obtained using three different methods: (i) the maximum RC (MRC) values on the left and right sides, (ii) the average RC (ARC) values on left and right sides, and (iii) the combined average RC (CARC) from both sides. Only rater 1 measured the 24 repeated US scans once. Raters 1 and 2 measured the RC index twice on all 58 images in 1 week apart. The intraclass correlation coefficient ICC [3, 1] for test-retest and ICC [2, 1] for intra- and inter-rater reliabilities as well as the standard error of measurements (SEM) were reported., Results: The means of scan 1 versus scan 2 were 0.16 ± 0.08 versus 0.16 ± 0.07 for left-MRC, 0.17 ± 0.11 versus 0.18 ± 0.11 for right-MRC, 0.08 ± 0.04 versus 0.09 ± 0.04 for left-ARC, 0.09 ± 0.04 versus 0.09 ± 0.05 for right-ARC and 0.08 ± 0.04 versus 0.09 ± 0.03 for CARC and all ICC[3, 1] ≥ 0.77. Among these 5 approaches, the CARC provided the best intra-rater and inter-rater reliabilities with ICC [2, 1] ≥ 0.84 and SEM ≤ 0.01., Conclusions: The RC index could be measured repeatably and reliably. The high RC value may reduce the risk of progression of scoliosis., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Surgical treatment of severe adolescent idiopathic scoliosis (AIS) with posterior spinal instrumentation and fusion with pedicle screws is common, requiring careful screw insertion to prevent pedicle breaches and neurologic complications. Image guidance has been suggested to improve breach rates, though the radiation risk for AIS precludes its common usage. The purpose of this systematic review and meta-analysis was to compare the breach rates and screw-related complications for AIS patients undergoing spine surgery with pedicle screws between freehand screw insertion and image guidance methods., Methods: A comprehensive search of MEDLINE, EMBASE, CINAHL, CENTRAL and Web of Science databases was conducted. Two reviewers independently screened abstracts, full-texts, extracted data and performed risk of bias assessment using the QUIPS quality appraisal tool. Level of evidence summary statements were formulated based on consistency and quality of reporting., Results: Ninety-four studies were found, with 18 studies of moderate risk of bias or better. Moderate evidence from two head-to-head studies shows CT guidance has lower breach rates than freehand methods (OR 0.28 [0.20-0.40, I 2  = 1%]), with no complications in either study. From individual studies, moderate evidence showed lower breach rates for image guidance versus freehand methods (13%, I 2  = 98% vs. 20%, I 2  = 95%). Complication rates were conflicting (0-1.6% for image guidance, 0-1.7% for freehand). Moderate evidence showed increased surgical time for image guidance versus freehand (257.7 min vs. 226.8 min)., Conclusions: Meta-analyzed breach rates show moderate evidence of decreased breaches with CT navigation compared with freehand methods. Complication rates remain unknown due to the low complication rates from small sample sizes. These slides can be retrieved under Electronic Supplementary Material.

Purpose: This study aimed to determine the intra- and inter-rater reliabilities of spinal flexibility measurements using ultrasound imaging on non-surgical candidates with adolescent idiopathic scoliosis (AIS)., Methods: Twenty-eight consecutive consented AIS subjects (25 F; 3 M) were recruited; 24 subjects' data were used for analysis. This study explored curve magnitude differences between standing, prone and voluntary maximum side-bending postures to assess the reliability of spinal flexibility (SF). Two raters were included in this study. Four flexibility indices, PRSI, BRPI, B-PRSI, BRSI, based on the postural changes from standing to prone and from prone to bending position were defined. The reliability analysis was evaluated using the intra-class correlation coefficient (ICC) [1, 2] and the standard error of measurements (SEM)., Results: The ICC [1, 2] values of the intra-rater (R2 only) and inter-rater (R1 vs R2) reliabilities of the measurements (PRSI, BRPI, B-PRSI, BRSI) were (0.82, 0.64, 0.78, 0.91) and (0.78, 0.76, 0.84, 0.94), respectively. Among the four indices, the BRPI had the highest SEM values 1.42, and 0.73 for intra- and inter-raters results, respectively, while BRSI had the lowest SEM 0.04 and 0.02 for intra- and inter-rater, respectively., Conclusions: The BRPI, BRSI and B-PRSI could be measured reliably on US images when the Cobb angle at prone position was not close to zero. Using these three indices, information may provide more comprehensive information about the SF. Validity of spinal flexibility measurements still needed to be confirmed with a clinical study with more subjects. These slides can be retrieved under Electronic Supplementary Material.

Purpose: To investigate the threshold of the curve difference on ultrasound measurement relative to the previous radiographic measurements to detect curves progression in children who have idiopathic scoliosis (IS)., Methods: Two hundred children with IS (F:170, M:30; mean age: 14.6 ± 1.9) were recruited from a single center. A retrospective study on comparing the current ultrasound measurements with the previous radiographic measurements with threshold values from 3° to 8° to detect curve progression was conducted. The receiver operating characteristic (ROC) analysis, accuracy (ACC), and odd ratio (OR) were calculated to determine the optimal threshold value of the curve differences between ultrasound and previous radiographic measurement., Results: Both thresholds of 4° and 5° for curve difference from ultrasound scans presented the sensitivities ≥ 0.90 and specificities ≥ 0.85, and can reduce by 73 and 79% of radiographs on the studied subjects, respectively. Especially, for 4° threshold, the negative likelihood ratio (LR-) was only 0.08, which indicated that there is only 8% probability that the subject has progressed if the US measurement detected non-progression., Conclusions: The ultrasound imaging method can be applied to identify curve progression in children with IS. Four degree is the preferred threshold value to detect the curve which had progressed, since it also had the lower rate of undetected progressed cases (false negatives).

Purpose: This study aimed to investigate the intra- and inter-observer reliability of the axial vertebral rotation (AVR) measurements of adolescent idiopathic scoliosis (AIS) using the center of lamina (COL) method on ultrasound transverse images., Methods: Three cadaver vertebrae were scanned with 42 AVR configurations by both ultrasound and radiograph. In this in vitro study, four observers measured the AVR using the COL method on ultrasound transverse images and three observers measured the AVR using the Stokes' method on radiographs. In the in vivo study, 13 AIS subjects were recruited. Eighteen spinal curvatures were identified and 48 vertebrae were selected for the AVR measurements. Two observers performed the AVR measurements on both the ultrasound images and radiographs. All measurements were performed twice with 1 week interval apart to reduce memory bias. The intraclass correlation coefficient (ICC), mean absolute differences (MAD), and standard deviation (SD) were used to analyze the intra- and inter-observer reliability of the AVR measurements. The Bland-Altman plot was used to analyze the 95 % limit of the differences between the two methods., Results: The proposed COL method had high intra- and inter-observer reliability on both the in vitro and in vivo studies (ICCs > 0.91, MADs < 1.4°) and agreed well with the experimental setup (ICCs > 0.96, MADs < 2.3°). The COL method showed good agreement with the Stokes' method for the in vitro study (ICC 0.84-0.85, MAD 4.5°-5.0°), while poor agreement for the in vivo study (ICC 0.49-0.54, MAD 2.7°-3.5°)., Conclusions: The pilot study indicated the proposed COL method was a simple and reliable method to evaluate the AVR on ultrasound images. Standardization of the posture during ultrasound scan and taking radiograph is important.

Purpose: To determine the reliability of a prognostic curve progression model and the role of the quantity and quality of brace wear for adolescent idiopathic scoliosis (AIS) brace treatment., Methods: To develop a curve progression model for full-time AIS brace treatment, 20 AIS subjects (Group 1) prescribed full-time thoracolumbar sacral orthosis (TLSO) were monitored and followed for 2 years beyond maturity. The developed curve progression model was: curve progression (in degrees) = 33 + 0.11 × Peterson risk (%) - 0.07 in-brace correction (%) - 0.45 × quality (%) - 0.48 × quantity (%) + 0.0062 × quantity × quality. To validate the model, 40 new (test) subjects (Group 2) who met the same inclusion criteria and used the same type of monitors, were monitored and followed for 2 years after bracing., Results: For the 40 test subjects (Group 2), the average in-brace correction was 40 ± 22 %. The average quantity and quality of the brace wear were 56 ± 19 and 55 ± 17 %, respectively. Twelve subjects (30 %) progressed of which 10 subjects (25 %) required surgery and 28 subjects (70 %) showed no progression. The accuracy of the model to determine which patients would progress was 88 % (35/40) which was better than the Peterson's risk model (68 %; 26/40) alone. Patients who had the combined quantity times the quality over a threshold 43 % had a success treatment rate of 95 %., Conclusions: This study showed the prognostic model of brace treatment outcome on AIS patients treated with full-time TLSO was reliable. Both the quantity and quality of the brace wear were important factors in achieving successful brace treatment.

Purpose: The objectives of this preliminary study were to assess the reliability and accuracy of ultrasound (US) for measuring coronal curvature with and without the aid of a previous radiograph, and to evaluate the ability of US to detect curve progression in adolescent idiopathic scoliosis (AIS) patients., Methods: Four raters measured 20 AIS US images twice at one-week intervals. Intra-rater reliability and correlation with radiograph were investigated with (rater 1) and without (raters 2-4) the aid of a previous radiograph. The center of lamina (COL) method was used to approximate the Cobb angle., Results: Thirty-six curves were identified. All raters showed high intra-rater reliability (ICC[2,1] >0.80). With the aid of a previous radiograph, rater 1 showed higher correlation with radiograph (ICC[2,1] = 0.86), better standard error of measurement (SEM = 2.2°), and improved error index of selecting end-vertebrae (EI = 1.34), but no statistical improvement of intra-rater reliability (p > 0.05). For rater 2-4, the range of the ICC[2,1] values between US and radiograph measurements, the SEM value, and the range of the EI values were 0.70°-0.72°, 3.3°, and 1.65°-2.36°, respectively. Specificity and sensitivity of US for detecting curve progression were 0.91 and 0.83, respectively., Conclusions: Using a previous radiograph as a measurement aid helped the user to measure coronal curvature from US images, and improved the accuracy of end-vertebrae selection. US showed high sensitivity and specificity for detecting curve progression, indicating that US may be a suitable, radiation-free alternative for monitoring patients with AIS who have mild or moderate curves.

Purpose: To investigate the accuracy and reliability of the Cobb angle, the spinous process angle (SPA), and apical vertebral rotation (AVR) for measuring adolescent idiopathic scoliosis (AIS), and to evaluate the correlations between these measurements., Methods: A retrospective study of two sets of standing posteroanterior radiographs of patients with AIS was performed. The first set was 59 consecutive patients with AIS with Cobb angles <45° and the second set was 25 patients with Cobb angles >45°. The Cobb angle, SPA and AVR of each curve was measured twice by three observers with varying measurement experience. The mean absolute difference, standard deviation, and intra- and inter-rater reliability coefficients for each measurement were examined. The Pearson correlation coefficients between any two parameters were reported. The association of the Cobb angle with the SPA and AVR was examined using a multiple regression model., Results: The average intra- and inter-observer reliabilities (ICC [2, 1]) of the Cobb angle, SPA, and AVR were 0.99, 0.95, 0.92 and 0.98, 0.88, 0.83, respectively. The correlation coefficients (r) between Cobb angle and SPA, Cobb angle and AVR, and SPA and AVR were 0.93, 0.68, and 0.60, respectively. Using multiple regression, the association between the Cobb angle and SPA combined with AVR was R (2) = 0.90. The resulting regression model was: [Formula: see text]., Conclusion: The SPA has high correlation with the Cobb angle. Including the AVR as an additional factor in multiple regression improves the prediction of the Cobb angle.