Comparison of manual and digital measurements in adolescent idiopathic scoliosis

Machine learning and regression analysis for age estimation from the iliac crest based on computed tomographic explorations in an Indian population

Age estimation constitutes an integral parameter of identification. In children, sub-adults, and young adults, accurate age estimation is vital on various aspects of civil, criminal, and immigration law. The iliac crest presents as a suitable age marker within these age cohorts, and the modified Risser method constitutes a relatively novel and unexplored method for iliac crest age estimation. The present study attempted to ascertain the applicability of this modified method for age estimation in the Indian population, an aspect previously unexplored, through computed tomographic examination of the iliac crest. Computed tomography scans of consenting individuals undergoing routine examinations of the pelvis/ abdomen for various clinically indicated reasons were collected and scored using the modified Risser stages. Computed tomographic examinations of the iliac crest indicate that the recalibrated method accurately depicts the temporal progression of ossification and fusion changes. Different regression and machine learning models were subsequently derived and/or trained to evaluate the accuracy and precision associated with the method. Amongst the ten regression models derived herein, compound regression exhibited the lowest inaccuracy (4.78 years) and root mean squared error values (5.46 years). Machine learning yielded further reduced error rates, with decision tree regression achieving inaccuracy and root mean squared error values of 1.88 years and 2.28 years, respectively. A comparative evaluation of error computations obtained from regression analysis and machine learning illustrates the statistical superiority of machine learning for forensic age estimation. Error computations obtained with machine learning suggest that the modified Risser method is capable of permitting reliable age estimation within criminal and civil proceedings.

The Influence of Radiographic Parameter on the S2 Alar-Iliac Screw Virtual Trajectory in Degenerative Lumbar Scoliosis Patients: A Computed Tomography Study

OBJECTIVE

S2 alar-iliac (S2AI) screw had been widely used in the pelvic fusion for degenerative lumbar scoliosis (DLS) patients. However, whether S2AI screw trajectory was influenced by sagittal profile in DLS patients had not been comprehensively investigated. The objective of this study was to evaluate the associations between the optimal S2 alar-iliac (S2AI) screw trajectory and sagittal spinopelvic parameters in DLS patients.

METHODS

Computed tomography (CT) scans of pelvis were performed in 47 DLS patients for three-dimensional reconstruction of S2AI screw trajectory from September 2019 to November 2021. Five S2AI screw trajectory parameters were measured in CT reconstruction images, including: 1) angle in the transverse plane (Tsv angle); 2) angle in the sagittal plane (Sag angle); 3) maximal screw length; 4) screw width; and 5) skin distance. The lumbar Cobb angle, lumbar apical vertebral translation (AVT); global kyphosis (GK); thoracic kyphosis (TK); lumbar lordosis (LL); sagittal vertical axis (SVA); sacral slope (SS); pelvic tilt (PT); and pelvic incidence (PI) were measured in standing X-ray films of the whole spine and pelvis.

RESULTS

Both Tsv angle and Sag angle had significant positive associations with SS (p < 0.05) but negative associations with both PT (p < 0.05) and LL (p < 0.05) in all cases. Patients with SS less than 15° had both smaller Tsv angle and Sag angle than those with SS equal to or more than 15° (p < 0.05). The decreased LL would lead to the backward rotation of the pelvis, resulting in a more cephalic and less divergent trajectory of S2AI screw in DLS patients.

CONCLUSIONS

For DLS patients with lumbar kyphosis, spine surgeons should avoid both excessive Tsv and Sag angles for S2AI screw insertion, especially when using free-hand technique.

Ponte Osteotomies in the Surgical Treatment of Adolescent Idiopathic Scoliosis: A Systematic Review of the Literature and Meta-Analysis of Comparative Studies

The purpose of the present paper is to assess if Ponte osteotomies (POs) allow for a better correction in adolescent idiopathic scoliosis (AIS) surgery and to investigate their safety profile. A systematic search of electronic databases was conducted. Inclusion criteria: comparative studies that reported the outcomes of AIS patients who underwent surgical correction through posterior-only approach with and without POs. Clinical and radiographic outcomes were extracted and summarized. Meta-analyses were performed to estimate the differences between patients treated with and without POs. p < 0.05 was considered significant. In total, 9 studies were included. No significant difference in thoracic kyphosis (TK) change between patients treated with and without POs was found (+3.8°; p = 0.06). Considering only hypokyphotic patients, a significant difference in TK change resulted in POs patients (+6.6°; p < 0.01), while a non-significant TK change resulted in normokyphotic patients (+0.2°; p = 0.96). No significant difference in coronal correction (2.5°; p = 0.10) was recorded. Significant estimated blood loss (EBL) (142.5 mL; p = 0.04) and surgical time (21.5 min; p = 0.04) differences were found with POs. Regarding complications rate, the meta-analysis showed a non-significant log odds ratio of 1.1 (p = 0.08) with POs. In conclusion, POs allow for the restoration of TK in hypokyphotic AIS, without a significantly greater TK change in normokyphotic patients, nor a significantly better coronal correction. Considering the significantly greater EBL and the trend toward a higher complications rate, the correct indication for POs is crucial.

Is the pelvic incidence a determinant factor for kyphosis curve patterns of ankylosing spondylitis patients?

To investigate the influence of pelvic incidence (PI) on the kyphosis curve patterns and clinical outcomes in ankylosing spondylitis (AS) patients with thoracolumbar kyphosis and to construct a classification of AS according to the PI value for surgical decision-making. 107 AS patients underwent single-level lumbar pedicle subtraction osteotomy (PSO) and finished a minimal of 2-year follow-up. All patients were divided into three groups: low PI (PI ≤ 40°), moderate PI (40° < PI ≤ 60°), and high PI (PI > 60°). Standing lateral radiographs were taken to evaluate the location of kyphotic apex, thoracic kyphosis (TK), lumbar lordosis (LL), C7 sagittal vertical axis (SVA), spino-sacral angle (SSA), global kyphosis (GK), PI, sacral slope (SS), and pelvic tilt (PT). Visual Analogue Scale (VAS) score, Oswestry Disability Index (ODI) and Bath Ankylosing Spondylitis Functional Index (BASFI) were used to evaluate quality of life. Before surgery, a significant difference was shown in the average LL and the mean GK in high PI group was the largest among the three groups. Correction of SVA, GK and LL in high PI group was the smallest among the three group. No significant difference in clinical outcomes was found among the three groups before surgery and at the final follow-up. Regarding the preoperative sagittal profile, the kyphosis curve pattern of moderate PI group is similar to that of low PI group. For AS patients in these two groups, harmonious sagittal alignment can be restored by a single-level PSO. However, the sagittal imbalance is insufficiently realigned by a single-level PSO in a patient with high PI.

Effectiveness of Orthotic Treatment on Clinical Outcomes of the Patients with Adolescent Idiopathic Scoliosis Under Different Wearing Compliance Levels: A Systematic Review

BACKGROUND

Wearing spinal orthosis for 16 to 23 hours a day during the teenage years could be challenging and stressful for patients with adolescent idiopathic scoliosis (AIS). The investigation of clinical outcomes under various orthosis-wearing compliances can provide helpful insight into orthotic treatment dosage. This systematic review aims to investigate actual orthosis-wearing compliance and evaluate the effectiveness of orthotic treatment in controlling scoliotic curvature and preventing surgery for patients with AIS under various levels of orthosis-wearing compliance.

METHODS

A literature search of 7 electronic databases, namely PubMed, MEDLINE, Cochrane Library, Scopus, CINAHL Complete, Web of Science, and Embase, was conducted on May 19, 2023. Participant characteristics, orthotic treatment protocols, compliance information, outcome measures, and key findings were extracted. The Newcastle-Ottawa Scales were used to evaluate the quality of included cohort and case-control studies.

RESULTS

This study systematically reviewed 17 of 1,799 identified studies, including 1,981 subjects. The actual compliance was inconsistent and ranged from 7.0 to 18.8 hours daily. The proportion of compliant subjects in each study varied from 16.0% to 78.6% due to the heterogeneity of calculation period, measurement methods, and orthosis prescription time. Thirteen studies were investigated to determine the effectiveness of orthotic treatment in controlling curve deformity under different compliance groups, and 2 studies compared the compliance under different treatment outcomes. The rate of curve progression, defined as surpassing the measurement error threshold of 5° or 6° after orthotic treatment, varied from 1.8% to 91.7% across the studies. Ten studies defined the treatment failure, surgery, or surgery indication as Cobb angle progressing to a certain degree (e.g., 40°, 45°, or 50°) and reported failure/surgery/surgery indication rates ranging from 0.0% to 91.7% among different compliance level groups.

CONCLUSION

This review found that the actual compliance with orthotic treatment was generally lower than the prescribed wearing time and exhibited wide variation among different studies. The electronic compliance monitors show promise in regular orthotic treatment practice. More importantly, the group with higher and consistent compliance has significantly less curve progression and lower surgery or failure rate than the group with lower and inconsistent compliance. Further studies are proposed to investigate the minimal orthosis-wearing compliance in patients with AIS treated with different types of orthoses.

LEVEL OF EVIDENCE

Level III, Systematic Review. See Instructions for Authors for a complete description of levels of evidence.

Prediction of future curve angle using prior radiographs in previously untreated idiopathic scoliosis: natural history from age 6 to after the end of growth (SOSORT 2022 award winner)

PURPOSE

Treatment selection for idiopathic scoliosis is informed by the risk of curve progression. Previous models predicting curve progression lacked validation, did not include the full growth/severity spectrum or included treated patients. The objective was to develop and validate models to predict future curve angles using clinical data collected only at, or both at and prior to, an initial specialist consultation in idiopathic scoliosis.

METHODS

This is an analysis of 2317 patients with idiopathic scoliosis between 6 and 25 years old. Patients were previously untreated and provided at least one prior radiograph prospectively collected at first consult. Radiographs were re-measured blinded to the predicted outcome: the maximum Cobb angle on the last radiograph while untreated. Linear mixed-effect models were used to examine the effect of data from the first available visit (age, sex, maximum Cobb angle, Risser, and curve type) and from other visits while untreated (maximum Cobb angle) and time (from the first available radiograph to prediction) on the Cobb angle outcome. Interactions of the first available angle with time, of time with sex, and time with Risser were also tested.

RESULTS

We included 2317 patients (83% of females) with 3255 prior X-rays where 71% had 1, 21.1% had 2, and 7.5% had 3 or more. Mean age was 13.9 ± 2.2yrs and 81% had AIS. Curve types were: 50% double, 26% lumbar/thoracolumbar-lumbar, 16% thoracic, and 8% other. Cobb angle at the first available X-ray was 20 ± 10° (0-80) vs 29 ± 13° (6-122) at the outcome visit separated by 28 ± 22mths. In the model using data at and prior to the specialist consult, larger values of the following variables predicted larger future curves: first available Cobb angle, Cobb angle on other previous X-ray, and time (with Time2 and Time3) to the target prediction. Larger values on the following variables predicted a smaller future Cobb angle: Risser and age at the first available X-ray, time*Risser and time*female sex interactions. Cross-validation found a median error of 4.5o with 84% predicted within 10°. Similarly, the model using only data from the first specialist consult had a median error of 5.5o with 80% of cases within 10° and included: maximum Cobb angle at first specialist consult, Time, Time2, age, curve type, and both interactions.

CONCLUSIONS

The models can help clinicians predict how much curves would progress without treatment at future timepoints of their choice using simple variables. Predictions can inform treatment prescription or show families why no treatment is recommended. The nonlinear effects of time account for the rapid increase in curve angle at the beginning of growth and the slowed progression after maturity. These validated models predicted future Cobb angle with good accuracy in untreated idiopathic scoliosis over the full growth spectrum.

Spino-pelvic radiological parameters: Comparison of measurements obtained by radiologists using the traditional method versus spine surgeons using a semi-automated software (Surgimap)

Background

Spinopelvic balance measurement is a key point to get an appropriate diagnosis and treatment in a group of spine pathologies; thus, it seems necessary the evaluation of different methods for obtaining the most reliable values. For that reason, different automatic and semi-automatic computer-assisted tools have been developed, and one example of them is Surgimap.

Purpose

To demonstrate that the sagittal balance measurements with Surgimap are equal and more time-efficient than with Agfa-Enterprise.

Material and Methods

Retrospective-prospective study. Biased comparative analysis of radiographic measurements performed on two different occasions (96 h interval), between two spine surgeons using Surgimap and two radiologists using the traditional Cobb method (TCM) with the Agfa-Enterprise program in 36 full spine lateral X-ray, determining inter- and intra-observer reliability and the mean time required to obtain the measurements.

Results

Measurements with both methods demonstrated an excellent intra-observer correlation (Surgimap: PCC 0.95 [0.85-0.99]; TCM: PCC 0.90 [0.81-0.99]). Inter-observer correlation also demonstrated an excellent relationship (PCC >0.95). Thoracic kyphosis (TK) demonstrated the lowest levels of inter-observer correlation (PCC: 0.75). The average time in seconds with TCM was 154.6, while with the Surgimap it was 41.8 s.

Conclusion

Surgimap proved to be equally reliable and 3.5 times faster. Therefore, in consistency with the available literature, our results would allow us to promote the use of Surgimap as a clinical diagnostic tool considering precision and efficiency.

Radiographic patterns and characteristics of sagittal profiles in normal spinopelvic curvatures: An explicit depiction of the distribution of lumbar vertebral bodies and discs

The current study aimed to investigate the sagittal morphology of the spinopelvic complex and the components of the lumbar spine in the normal population. In total, 132 adult volunteers were retrospectively evaluated and divided into four groups according to the Roussouly classification. Statistical analysis of radiological parameters, including lumbar lordosis (LL), thoracic kyphosis (TK), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), PI-LL, LL-TK, lumbar vertebral lordosis from L1 to L5 (L1L-L5L), the intervertebral angle from L1-L2 to L5-S1 (IVA1-2-IVA5-1), segmental lordosis from L1 to L5 (S1L-S5L), the proportion of L1-L5 (L1%-L5%), the proportion of the intervertebral angle from L1-L2 to L5-S1 (IVA1-2%-IVA5-1%), and proportion of segmental lordosis from L1 to L5 (S1L%-S5L%), was performed. Based on the classification, type II (n = 46) was the most common, followed by type I (n = 39), type III (n = 36), and type IV (n = 11). The quantitative values of the sagittal parameters of the four groups were obtained. Results showed a significant difference in terms of LL, PI, SS, and LL-TK. Further, L1%, L2%, L3%, IVA1-2%, IVA2-3%, S1L%, S2L%, and S3L% had an increasing trend. PI was positively correlated with LL, S1L, S2L, S3L, S4L, S1L%, and S2L%, but not with S5L%. In conclusion, pelvic parameters had a significant effect on lumbar curvature and lordosis distribution. Further, the abovementioned results were beneficial for individual surgical decision-making regarding targeted intervertebral angle, screw-insertion dimension, and rod contouring.

Does the Level of Pedicle Subtraction Osteotomy Affect the Surgical Outcomes in Ankylosing Spondylitis-Related Thoracolumbar Kyphosis With the Same Curve Pattern?

STUDY DESIGN

A retrospective study.

OBJECTIVE

To investigate the effect of pedicle subtraction osteotomy (PSO) level on the surgical outcomes in ankylosing spondylitis-related thoracolumbar kyphosis with the same curve pattern.

METHODS

ankylosing spondylitis (AS) patients with thoracolumbar kyphosis, who underwent 1-level lumbar PSO between March 2006 and June 2017, were retrospectively reviewed. Criteria for curve-matched thoracolumbar kyphosis were: (1) have same level of preoperative apex (pre-apex); (2) have similar global kyphosis (GK, the angle between the superior/inferior endplate of the maximally tilted upper and lower end vertebra) (the difference of GK less than 15˚). The radiographic parameters measured were sagittal vertical axis (SVA, the horizontal distance between the C7 plumb line and the posterosuperior corner of the S1), GK, thoracic kyphosis (TK, the angle between the T5 superior endplate and the T12 inferior endplate), lumbar lordosis (LL, the angle between the L1 and S1 superior endplate), sacral slope (SS, the angle between the sacral endplate and the horizontal line), pelvic tilt (PT, the angle between the vertical and the line joining the midpoint of the sacral plate and hip axis), and pelvic incidence (PI, the angle between the line vertical to the superior margin of S1 and the line connecting the sacral plate midpoint with the hip joint axis). All of these parameters and health-related quality of life (HRQoL, evaluated by preoperative and the last follow-up questionnaires including ODI and VAS) scores were collected before surgery and at the last follow-up. According to their osteotomy level, patients were devided into 2 sub-groups (L1 group and L2 group), and differences of these mentioned parameters between 2 groups were compared.

RESULTS

26 curve-matched patients were recruited with a mean follow-up of 37.2 months. All patients improved significantly after surgery in HRQoL scores (VAS 1.6 vs 5.4, P < 0.001; ODI 11.9 vs 26.4, P < 0.001). Except for TK and PI, those radiographic parameters were also observed to be significantly changed after surgery. Compared to L2 group, PSO at L1 may have larger correction of TK (ΔTK -6.8 vs -0.3°, P = 0.164), PI (ΔPI -7.4 vs -0.7°, P = 0.364) and smaller correction of SVA (ΔSVA -105.3 vs -128.5 mm, P = 0.096), LL (ΔLL -31.1 vs -43.0°, P = 0.307) and SS (ΔSS 6.9 vs 12.2°, P = 0.279) but had no statistical significance.

CONCLUSION

The results of this investigation showed that in AS-related thoracolumbar kyphosis patients with the same curve pattern, the different levels of osteotomy had little effect on the improvement of surgical outcomes. However, osteotomy at L2 is more likely to obtain a larger correction of SVA compared to osteotomy at L1.

Postoperative shoulder balance in Lenke type 1 adolescent idiopathic scoliosis patients with large thoracic curve (Cobb angle ≥ 70 degrees): a radiographic study

Background

Large amounts of thoracic curve correction had been considered as a risk factor for postoperative shoulder imbalance (PSI) in adolescent idiopathic scoliosis (AIS) patients. This study aims to evaluate postoperative shoulder balance in Lenke type 1 AIS patients with large thoracic curve (Cobb angle ≥ 70 degrees) and compared it with those with moderate thoracic curve (Cobb angle < 70 degrees).

Methods

A total of 47 Lenke type 1 AIS patients underwent posterior correction surgery between Sept. 2016 to Nov. 2018 in our institution were included. All these patient were divided into 2 groups based on the severity of main thoracic (MT) curve. Group A consisted of 25 cases with MT curve equal to or more than 70 degree while Group B consisted of 22 cases with MT curve less than 70 degree. Proximal thoracic (PT) Cobb angle, MT Cobb angle, MT apical vertebral translation (AVT), T2-T5 kyphosis, T5-T12 kyphosis, and radiographic shoulder height (RSH) were compared between these 2 groups preoperatively, immediately after surgery, and at a minimum of two-year follow-up.

Results

Although all the correction of PT Cobb angle (15.8° ± 6.0° vs 12.5° ± 3.6°, P = 0.028), that of MT Cobb angle 47.3° ± 9.1° vs 30.9° ± 6.7°, P < 0.001) and that of MT AVT (35.1 mm ± 16.0 mm vs 24.1 mm ± 8.9 mm, P = 0.007) were significantly larger in Group A when compared with Group B, RSH was comparable between these 2 groups at last follow up (7.5 mm ± 7.4 mm vs 9.2 mm ± 4.2 mm P = 0.363). Most of the patients gained satisfactory shoulder balance with only 7 cases with minimal PSI in group A (28%) and only 6 cases with minimal PSI in group B (27.3%) at last follow-up (P > 0.05).

Conclusions

Although Lenke type 1 AIS patients with large thoracic curve had more amounts of MT curve correction when compared with those with moderate thoracic curve, it did not lead to higher incidence of PSI if the correction rate is proper.

Validity and Absolute Reliability of the Cobb Angle in Idiopathic Scoliosis with TraumaMeter Software

The Cobb angle value is a critical parameter for evaluating adolescent idiopathic scoliosis (AIS) patients. This study aimed to evaluate a software’s validity and absolute reliability to determine the Cobb angle in AIS digital X-rays, with two different degrees of experienced observers. Four experts and four novice evaluators measured 35 scoliotic curves with the software on three separate occasions, one month apart. The observers re-measured the same radiographic studies on three separate occasions three months later but on conventional X-ray films. The differences between the mean bias errors (MBE) within the experience groups were statistically significant between the experts (software) and novices (manual) (p < 0.001) and between the novices (software) and novices (manual) (p = 0.005). When measured with the software, the intra-group error in the expert group was MBE = 1.71 ± 0.61° and the intraclass correlation coefficient (ICC (2,1)) = 0.986, and in the novice group, MBE = 1.9 ± 0.67° and ICC (2,1) = 0.97. There was almost a perfect concordance among the two measurement methods, ICC (2,1) = 0.998 and minimum detectable change (MCD95) < 0.4°. Control of the intrinsic error sources enabled obtaining inter- and intra-observer MDC95 < 0.5° in the two experience groups and with the two measurement methods. The computer-aided software TraumaMeter increases the validity and reliability of Cobb angle measurements concerning manual measurement.

Validity and reliability of a computer-assisted system method to measure axial vertebral rotation

BACKGROUND

Axial vertebral rotation and Cobb's angle are essential parameters for analysing adolescent idiopathic scoliosis. This study's scope evaluates the validity and absolute reliability of application software based on a new mathematical equation to determine the axial vertebral rotation in digital X-rays according to Raimondi's method in evaluators with different degrees of experience.

METHODS

Twelve independent evaluators with different experience levels measured 33 scoliotic curves in 21 X-rays with the software on three separate occasions, separated one month. Using the same methodology, the observers re-measured the same radiographic studies three months later but on X-ray films and in a conventional way.

RESULTS

Both methods show good validity and reliability, and the intraclass correlation coefficients are almost perfect. According to our results, the software increases 1.7 times the validity and 1.9 times the absolute reliability of axial vertebral rotation on digital X-rays according to Raimondi's method, compared to the conventional manual measurement.

CONCLUSIONS

The intra-group and inter-group agreement of the measurements with the software shows equal or minor variations than with the manual method, among the different measurement sessions and in the three experience groups. There is almost perfect agreement between the two measurement methods, so the equation and the software may be helpful to increase the accuracy in the axial vertebral rotation assessment.

Radiophobia Overreaction: College of Chiropractors of British Columbia Revoke Full X-Ray Rights Based on Flawed Study and Radiation Fear-Mongering

Fears over radiation have created irrational pressures to dissuade radiography use within chiropractic. Recently, the regulatory body for chiropractors practicing in British Columbia, Canada, the College of Chiropractors of British Columbia (CCBC), contracted Pierre Côté to review the clinical use of X-rays within the chiropractic profession. A "rapid review" was performed and published quickly and included only 9 papers, the most recent dating from 2005; they concluded, "Given the inherent risks of radiation, we recommend that chiropractors do not use radiographs for the routine and repeat evaluation of the structure and function of the spine." The CCBC then launched an immediate review of the use of X-rays by chiropractors in their jurisdiction. Member and public opinion were gathered but not presented to their members. On February 4, 2021, the College announced amendments to their Professional Conduct Handbook that revoked X-ray rights for routine/repeat assessment and management of patients with spine disorders. Here, we highlight current and historical evidence that substantiates that X-rays are not a public health threat. We also point out critical and insurmountable flaws in the single paper used to support irrational and unscientific policy that discriminates against chiropractors who practice certain forms of evidence-based X-ray-guided methods.

Computerized image understanding system for reliable estimation of spinal curvature in idiopathic scoliosis

Analysis of scoliosis requires thorough radiographic evaluation by spinal curvature estimation to completely assess the spinal deformity. Spinal curvature estimation gives orthopaedic surgeons an idea of severity of spinal deformity for therapeutic purposes. Manual intervention has always been an issue to ensure accuracy and repeatability. Computer assisted systems are semi-automatic and is still influenced by surgeon’s expertise. Spinal curvature estimation completely relies on accurate identification of required end vertebrae like superior end-vertebra, inferior end-vertebra and apical vertebra. In the present work, automatic extraction of spinal information central sacral line and medial axis by computerized image understanding system has been proposed. The inter-observer variability in the anatomical landmark identification is quantified using Kappa statistic. The resultant Kappa value computed between proposed algorithm and observer lies in the range 0.7 and 0.9, which shows good accuracy. Identification of the required end vertebra is automated by the extracted spinal information. Difference in inter and intra-observer variability for the state of the art computer assisted and proposed system are quantified in terms of mean absolute difference for the various types (Type-I, Type-II, Type-III, Type-IV, and Type-V) of scoliosis.

Reliability of 2 Smartphone Applications for Cobb Angle Measurement in Scoliosis

Background

As mobile technology has evolved, smartphone applications have been used for radiographic angle measurements in daily clinical practice. This study aimed to assess the reliability of 2 smartphone applications (iPinPoint and Cobbmeter) in measuring scoliosis Cobb angles compared with picture archiving and communication system (PACS) tools.

Methods

Anteroposterior whole spinal digital radiographs of 50 patients were retrospectively analyzed. Four observers measured Cobb angles of predetermined major structural curves using the tools in the PACS software and 2 smartphone applications. The inter- and intraobserver reliabilty were measured using intraclass correlation coefficients (ICC).

Results

Very good interobserver agreement was seen with PACS, iPinPoint, and Cobbmeter measurements (ICC, 0.991, 0.980, and 0.991, respectively). Intraobserver reliability of the 4 observers was also very good for all techniques (ICC > 0.9 for all observers).

Conclusions

Both smartphone applications were reliable in measuring scoliosis Cobb angles, with reference to PACS tools. They may be useful when digital or manual mesurement tools are not available.

Image Distortion in Biplanar Slot Scanning: Part 2 Technology-specific Factors

BACKGROUND

Biplanar digital slot scanning technology has become the standard of care in the treatment of scoliosis. Yet, the amount of distortion and reproducibility of this type of imaging modality has yet to be fully investigated. In our paper "Image distortion in biplanar slot scanning: part 1 patient-specific factors" we found that there was potentially clinically impactful interimage distortion. The purpose of this study was to evaluate the degree to which this image distortion was secondary to the image acquisition process.

METHODS

Four 25 mm radio-opaque markers were placed at C3, T1, T12, and L5 on a full-length skeleton model. The skeleton was imaged in 10 different positions within the scanner. Five posteroanterior and 5 lateral images were obtained in each position. Two orthopaedic attending physicians and 3 orthopaedic resident physicians measured the markers for a total of 3200 measurements. Intraclass correlation coefficients (ICCs) and 95% confidence intervals were used to examine image distortion.

RESULTS

Average marker size was 24.77, with a standard error of measurement of 0.00493. Image distortion and standard error of measurement accounted for ∼0.5% to 1.5% of total the measurement. Overall, there was good reliability and consistency when looking at markers in different views (ICC 0.790), planes, and locations within the image. Horizontal measurements were found to be more consistent and have better reliability (ICC 0.881) than vertical measurements (ICC 0.386). Position within the scanner had minimal impact on the accuracy of the measurements.

CONCLUSIONS

This study demonstrates that there is minimal error due to image acquisition and measurement when using a biplanar slot scanner. Biplanar slot scanning technology tended to underestimate the size of the marker; however, the least accurate measurements only erred by 1.5% from the true length. This indicates that unlike traditional radiographs the sources of error in biplanar slot scanning images are not due to parallax and are likely due to patient-specific factors and rather than the technology itself.

Developing of a Mathematical Model to Perform Measurements of Axial Vertebral Rotation on Computer-Aided and Automated Diagnosis Systems, Using Raimondi's Method

Introduction

Axial vertebral rotation (AVR) is a basic parameter in the study of idiopathic scoliosis and on physical two-dimensional images. Raimondi's tables are the most used method in the quantification of AVR. The development of computing technologies has enabled the creation of computer-aided or automated diagnosis systems (CADx) with which measurement on medical images can be carried out more quickly, simply, and with less intra and interobserver variabilities than manual methods. Although there are several publications dealing with the measurement of AVR in CADx systems, none of them provides information on the equation or algorithm used for the measurement applying Raimondi's method. Goal. The aim of this work is to perform a mathematical modelling of the data contained in Raimondi's tables that enable the Raimondi method to be used in digital medical images more precisely and in a more exact manner.

Methods

Data from Raimondi's tables were tabulated on a first step. After this, each column of Raimondi's tables containing values corresponding to vertebral body width (D) were adjusted to a curve determined by AVR = f (d). Third, representative values of each rotation divided by D were obtained through the equation of each column D. In a fourth step, a regression line was fitted to the data in each row, and from its equation, the mean value of the D/d distribution is calculated (value corresponding to the central column, D = 45). Finally, a curve was adjusted to the obtained data using the least squares method. Summary and Conclusion. Our mathematical equation allows the Raimondi method to be used in digital images of any format in a more accurate and simplified approach. This equation can be easily and freely implemented in any CADx system to quantify AVR, providing a more precise use of Raimondi's method, as well as being used in traditional manual measurement as it is performed with Raimondi tables.

Predictors for long-term curve progression after Boston brace treatment of idiopathic scoliosis

BACKGROUND

Identifying factors that predict successful bracing in patients with idiopathic scoliosis may help planning treatment.

AIM

To assess predictors for long-term curve progression and health-related quality of life after Boston brace treatment.

DESIGN

Observational retrospective cohort study with analysis of brace treated patients followed from start until at least 10 years after treatment.

SETTING

Patients recruited from the country's entire population consecutively treated at the National Hospital.

POPULATION

365 patients (339 girls/26 boys) with idiopathic scoliosis. Mean (SD) chronological age/bone age at start bracing was 13.2 (1.9)/12.6 (1.9) years. The primary major curve measured 33.2 (7.4°), and the major levels were thoracic (N.=248), thoracolumbar (N.=78) and lumbar (N.=39). Mean bracing time was 2.8 (1.5) years. Long-term follow-up was in average 23.3 (4.1) years after weaning with a mean major curve of 33.0 (13.1°). Successful treatment was defined as a stable primary curve with progression ≤5°, and secondary the SRS-22 questionnaire assessed quality of life.

METHODS

We applied linear or logistic regression with backward elimination. Internal validation was assessed by bootstrapping. Twelve variables were included in the prediction models: age, bone age, scoliosis in close family, major curve size, level, shape, flexibility and in-brace redressement, compliance, curve magnitude after 1 year, treatment time and quality of life (SRS-22).

RESULTS

290 patients (79%) had rated good compliance using the brace >20 hours daily. Treatment failure was observed in 65 patients (18%), and 27 of them were operated. The best baseline predictors were age and brace redressement. During treatment compliance, major curve after 1 year, and treatment time were the best predictors, while thoracic major curve, curve size at start bracing and scoliosis in close family also contributed to the final model. The model's ability to predict quality of life was low.

CONCLUSIONS

The best predictors for a long-term success were good redressement and compliance, unchanged or reduced major curve after one year and short treatment time.

CLINICAL REHABILITATION IMPACT

Predictors at baseline and during early treatment can help identifying patients who benefit from bracing.

A Nano-Dose Protocol For Cobb Angle Assessment in Children With Scoliosis: Results of a Phantom-based and Clinically Validated Study

STUDY DESIGN

This was a prospective validation study with technical notes.

OBJECTIVE

This study aimed to validate a new ultra-low-dose full-spine protocol for reproducible Cobb angle measurements-the "nano-dose" protocol.

SUMMARY OF BACKGROUND DATA

Scoliosis is a 3-dimensional (3D) deformity of the spine characterized by 3D clinical parameters. Nevertheless, 2D Cobb angle remains an essential and widely used radiologic measure in clinical practice. Repeated imaging is required for the assessment and follow-up of scoliosis patients. The resultant high dose of absorbed radiation increases the potential risk of developing radiation-induced cancer in such patients. Micro-dose radiographic imaging is already available in clinical practice, but the radiation dose delivered to the patient could be further reduced.

METHODS

An anthropomorphic child phantom was used to establish an ultra-low-dose protocol in the EOS Imaging System still allowing Cobb angle measurements, defined as nano-dose. A group of 23 consecutive children presenting for scoliosis assessment, 12 years of age or younger, were assessed with standard-dose or micro-dose and additional nano-dose full-spine imaging modalities. Intraobserver and interobserver reliability of determining the reliability of 2D Cobb angle measurements was performed. The dosimetry was performed in the anthropomorphic phantom to confirm theoretical radiation dose reduction.

RESULTS

A nano-dose protocol was established for reliable Cobb angle measurements. Dose area product with this new nano-dose protocol was reduced to 5 mGy×cm, corresponding to one sixth of the micro-dose protocol (30 mGy×cm) and <1/40th of the standard-dose protocol (222 mGy×cm). Theoretical dose reduction, for posteroanterolateral positioning was confirmed using phantom dosimetry. Our study showed good reliability and repeatability between the 2 groups. Cobb variability was <5 degrees from the mean using 95% confidence intervals.

CONCLUSIONS

We propose a new clinically validated nano-dose protocol for routine follow-up of scoliosis patients before surgery, keeping the radiation dose at a bare minimum, while allowing for reproducible Cobb angle measurements.

Transpedicular Wedge Resection Osteotomy of the Apical Vertebrae for the Treatment of Severe and Rigid Thoracic Kyphoscoliosis: A Retrospective Study of 26 Cases

STUDY DESIGN

Retrospective analysis of clinical records.

OBJECTIVE

To determine the efficacy of transpedicular wedge resection osteotomy (TWRO) of the apical vertebrae to treat severe and rigid thoracic kyphoscoliosis in 26 adults.

SUMMARY OF BACKGROUND DATA

Although posterior vertebral column resection has traditionally been used to correct severe and rigid kyphoscoliosis, TWRO may achieve the same correction with a shorter operative time and lower rate of complications.

METHODS

Between May 2011 and December 2014, 29 adults underwent a TWRO of the apical vertebrae for severe and rigid thoracic kyphoscoliosis, and 26 adults completed the 24-month follow-up. Radiologic measurements, including coronal plane major curve, kyphotic curve, coronal offset, and sagittal offset, were measured and compared. The following patient-reported health-related quality of life outcomes, including Oswestry Disability Index score, visual analog scale score for back pain, and SRS-22 questionnaire, were used to evaluate the clinical outcomes.

RESULTS

For the 26 patients followed over 24 months, the mean coronal plane major curve improved from 107.6° to 37.5° immediately after surgery and to 40.0° at 24 months postoperatively. The mean kyphotic curve improved from 90.6° to 30.5° immediately after surgery and to 33.3° at 24 months postoperatively. The mean coronal offset and sagittal offset were also improved. Improved self-reported quality of life scores were achieved postoperatively and at 24 months postoperatively, including all domains of the SRS-22 questionnaire. Bony fusion was achieved at 6 or 12 months in all patients. Unilateral leg paresis occurred in one case and recovered after three months, with a neurologic complication rate of 3.8%.

CONCLUSIONS

TWRO of the apical vertebrae as a treatment for severe and rigid thoracic kyphoscoliosis in adult patients provided excellent clinical outcomes. However, the procedure remains technically demanding and exhausting, with a potential risk for complications.

LEVEL OF EVIDENCE

Level IV.

Correlation of cervical and thoracic inlet sagittal parameters by MRI and radiography in patients with cervical spondylosis

To investigate the relationship between cervical and thoracic sagittal alignment parameters measured by magnetic resonance imaging (MRI) and x-ray in patients with cervical spondylosisData from 120 symptomatic patients who presented with cervical spondylosis between April 2015 and January 2016 were retrospectively analyzed. Patients received both a cervical MRI and a cervical radiograph during a single visit. The thoracic inlet angle (TIA), T1 slope (T1S), neck tilt (NT), C2-C7 angle (C2-C7), and C2-C7 sagittal vertical axis (C2-7 SVA) were assessed. Pearson correlation coefficient, paired t test, and linear regression models were used to analyze parameters obtained by cervical MRI and radiography.The difference in mean thoracic inlet angle x-ray (TIAX) and thoracic inlet angle MRI (TIAM) (TIAM-TIAX) (0.72 ± 5.82°) was not significant (P > .05). There were significant differences in mean T1 slope x-ray (T1SX) and T1 slope MRI (T1SM) (T1SM-T1SX) (-2.55 ± 6.14°), mean neck tilt x-ray (NTX) and neck tilt MRI (NTM) (NTM-NTX) (3.26 ± 6.01°), mean C2-C7 angle x-ray (C2-7X) and C2-C7 angle MRI (C2-7 M) (C2-7M-C2-7X) (-3.57 ± 10.00°), and mean C2-C7 sagittal vertical axis X ray (C2-7 SVAX) and C2-C7 sagittal vertical axis MRI (C2-7 SVAM) (C2-7 SVAM-C2-7 SVAX) (-4.50 ± 1.26 mm) (all P ≤ .001). There were positive correlations between TIAM and TIAX (r = 0.807), T1SM and T1SX (r = 0.581), NTM and NTX (r = 0.759), cervical loidosis MRI and cervical loidosis x-ray (r = 0.666), and SVAM and SVAX (r = 0.226).MRI may be useful to evaluate thoracic inlet and sagittal alignment parameters in patients with cervical spondylosis. Patients with cervical spondylosis may have a relatively low capacity for compensation in the cervical region.

Postoperative Lumbar Curve Progression Deteriorates Shoulder Imbalance in Patients with Lenke Type 2B/C Adolescent Idiopathic Scoliosis Who Underwent Selective Thoracic Fusion

OBJECTIVE

To evaluate the association between postoperative lumbar curve progression and the shoulder height in patients with Lenke type 2B/C adolescent idiopathic scoliosis (AIS).

METHODS

A total of 25 patients with Lenke type 2B/C AIS underwent posterior correction surgery in our institution from 2005-2014 were included. Standing x-ray films of the whole spine obtained before surgery, immediately after surgery, and at the last follow-up were analyzed with respect to the following parameters: proximal thoracic Cobb angle, main thoracic (MT) Cobb angle, lumbar Cobb angle, lumbar apical vertebral translation, distance between C7 plumb line and the central sacral vertical line, and radiographic shoulder height (RSH). Correlations between the change of RSH and the changes of other parameters were analyzed both immediately after surgery and at the last follow-up.

RESULTS

The change of RSH was significantly negatively correlated with both the change of MT Cobb angle (P < 0.05) and that of lumbar Cobb angle (P < 0.05) immediately after surgery, whereas the interval-time change of RSH was significantly positively correlated with the interval-time change of lumbar Cobb angle (P < 0.05) and that of lumbar apical vertebral translation (P < 0.05) at the last follow-up. The change of MT Cobb angle was an independent predictor for the change of RSH immediately after surgery, whereas the interval-time change of lumbar Cobb angle was an independent predictor for the interval-time change of RSH at the last follow-up.

CONCLUSIONS

Postoperative lumbar curve progression is a risk factor for deterioration of shoulder imbalance in patients with Lenke 2B/C AIS during the follow-up period.

Assessment of Inter- and Intraobserver Reliability and Accuracy to Evaluate Apical Vertebral Rotation Using Four Methods: An Experimental Study Using a Saw Bone Model

STUDY DESIGN

After placing a thoracic three-vertebra segment saw bones model on a standardized turntable, a series of anteroposterior (AP) radiographs were obtained and then set in increments to 90° rotation. Then the specimen was instrumented with 35-mm pedicle screws bilaterally and the rotation process and image acquisition were repeated.

OBJECTIVE

Assess reliability and accuracy of spine surgeons evaluating apical vertebral rotation (AVR) through surgeon's visual x-ray estimation, Nash-Moe system, Upasani trigonometric method, and Upasani grading system.

BACKGROUND CONTEXT

Accurate assessment of AVR is one measure surgeons can evaluate the success of intervention and potential loss of correction in scoliotic deformities.

METHODS

Eighty-four representative images of uninstrumented and instrumented vertebral segments were blinded. AVR was estimated by five experienced spinal deformity surgeons using the four techniques. The surgeons' grading, estimates, and errors compared to actual rotation were calculated. Inter- and intraobserver reliability were calculated using interclass correlation (ICC).

RESULTS

Each surgeon's error for simple visual estimation for uninstrumented segments was 8.7° to 17.4° (average error = 12.4°), and for instrumented segments it was 7.7° to 11.3° (average error = 9.5°). Error for the Upasani trigonometric method was -6.7° to 11.6° (average error = 0.9°). There was relatively poor accuracy for Nash-Moe system (38.2%-53.9%) compared with the Upasani grading system (76.74%-80.23%). Interobserver reliability using the Nash-Moe method was good (0.844), with intraobserver reliability from fair to excellent (0.684-0.949). Interobserver reliability for the Upasani grading method was good (0.829), with intraobserver reliability from fair to good (0.751-0.869). We found excellent interobserver reliability for Upasani trigonometric classification (0.935) with fair to excellent intraobserver reliability (0.775-0.991). The interobserver reliability of surgeons' visual estimates was good (0.898) and the intraobserver reliability from good to excellent (0.866-0.99) without pedicle screws, and interobserver reliability was excellent (0.948) and intraobserver reliability also excellent (0.959-0.986) with pedicle screws.

CONCLUSIONS

We confirm that both techniques described by Upasani have good reliability and accuracy, appearing more accurate than surgeon's visual estimates or Nash-Moe system.

LEVEL OF EVIDENCE

Level III.

Chimera of digital radiography in spine surgery: False diagnosis of implant failure

BACKGROUND

Digital radiographs of the whole spine are made using marginally superimposed imaging plates exposed simultaneously to be combined by interpolation of the overlapping area. Post-processing artefacts in these radiographs leading to the misdiagnosis of implant breakage have not yet been described in the literature.

METHODS

An erroneous fusion of a digital spine x-ray after scoliosis surgery created an image showing two broken rods, whereas both rods proved complete continuity intraoperatively. Following an interdisciplinary error analysis, the chain of errors was systematically reconstructed. Using the digital imaging material of patients operatively treated the same way; the reproducibility of the error was analyzed. Erroneous image fusions were produced by slight displacement of existing, not yet combined x-ray images of these patients.

RESULTS

Under certain requirements, the false impression of implant breakage could be reproduced. Especially in the case of missing or malpositioned radiopaque markers, the hazard to overlook an erroneous image fusion is present. Within the post-processing step performed by qualified staff, control is indispensable and manual correction can be crucial.

CONCLUSIONS

This experimental study and causal analysis show the clinical relevance of post-processing artefacts in digital radiography. To prevent false diagnosis and maltreatment, the knowledge of possible sources of error is indispensable.

Difference of Dynamic Morphometric Changes Between in Patients with Ossification of Posterior Longitudinal Ligament and Patients with Cervical Spondylosis: Assessment by Cervical Dynamic Magnetic Resonance Imaging

PURPOSE

To evaluate differences between thicknesses of the ligamentum flavum (LF) and diameter of the spinal canal in different neck positions in patients with ossification of the posterior longitudinal ligament (OPLL) and patients with cervical degenerative spondylosis (CDS) using cervical dynamic magnetic resonance imaging (MRI).

METHODS

Eighty-eight patients (66 CDS and 22 OPLL) who underwent neutral and dynamic MRI at our institute from February 2014 to July 2017 were the subjects of this retrospective study. Canal diameters and LF thicknesses were measured and Muhle's grades were determined in neutral and dynamic MRI from C2-C3 to C7-T1. Patients with CDS and OPLL were compared with respect to changes in morphometric parameters. Statistical analysis was performed using SPSS software and statistical significance was accepted for P values < 0.05.

RESULTS

Mean ages in the CDS and OPLL groups were 68.2 ± 12.27 and 63.1 ± 9.36 years, respectively. Mean canal diameters were smaller in extension than in neutral at all measured levels, especially between C3-C4 and C6-C7 in patients with CDS. LF thickness in extension was significantly greater than in neutral and flexion positions in the CDS group, but not in the OPLL group. In addition, positional changes in Muhle's grades in the CDS group were significantly greater than in the OPLL group (P = 0.042).

CONCLUSIONS

Dynamic morphometric changes were found to be significantly greater in the CDS group than in the OPLL group. The study shows dynamic MRI may provide additional information in CDS patients.

Standard reference values of the upper body posture in healthy young female adults in Germany: an observational study

OBJECTIVE

Classifications of posture deviations are only possible compared with standard values. However, standard values have been published for healthy male adults but not for female adults.

DESIGN

Observational study.

SETTING

Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe-University Frankfurt/Main.

PARTICIPANTS

106healthy female volunteers (21-30 years old; 25.1±2.7 years) were included. Their body weight ranged from 46 to 106 kg (60.3±7.9 kg), the heights from 1.53 to 1.82 m (1.69±0.06 m) and the body mass index from 16.9 kg/m² to 37.6 kg/m² (21.1±2.6 kg/m²).

OUTCOME MEASURES

A three-dimensional back scan was performed to measure the upper back posture in habitual standing. The tolerance ranges and CI were calculated. Group differences were tested by the Wilcoxon Mann-Whitney U test.

RESULTS

In normal posture, the spinal column was marginally twisted to the left, and the vertebrae were marginally rotated to the right. The kyphosis angle is larger than the lumbar angle. Consequently, a more kyphotic posture is observed in the sagittal plane. The habitual posture is slightly scoliotic with a rotational component (scapular depression right, right scapula marginally more dorsally, high state of pelvic right, iliac right further rotated anteriorly).

CONCLUSIONS

Healthy young women have an almost ideally balanced posture with minimal ventral body inclination and a marginal scoliotic deviation. Compared with young males, women show only marginal differences in the upper body posture. These values allow a comparison to other studies, both for control and patient data, and may serve as guideline in both clinical practice and scientific studies.

Cobb angle measurements on digital radiographs using Bunnell scoliometer: Validation of the method

BACKGROUND

Electronic rulers on computer screen are used to measure the Cobb angle (CA) instead of traditional methods with rulers, protractors and pens. The variety of software used to assess radiographs might make the CA measurements cumbersome in everyday clinical practice.

OBJECTIVE

The aim of the study was to verify the method of CA measurements on digital radiographs using Bunnell scoliometer (BS).

METHODS

Eighty patients with idiopathic scoliosis were enrolled into the study. CA of each curve was measured by use of Centricity software and BS. CA on 30 randomly chosen patients were measured 3 times by one researcher using only scoliometer. Three researchers measured CA on the same 30 radiographs using BS.

RESULTS

The mean CA of 224 curves measured by Centricity and BS were 29° ± 12.2° and 28° ± 11.7°, respectively. The ICC for agreement for 2 methods was 0.96 with SEM of 1.7°. Excellent intra- and interobserver reliability of CA measurements with scoliometer was noted: ICC of 0.96 with SEM of 1.4° and ICC of 0.93 with SEM of 1.9°, respectively.

CONCLUSIONS

The study revealed excellent reliability of CA measurements on digital radiographs using the BS. The proposed method of using the Bunnell scoliometer for CA measurements may be clinically useful.

Full fusion of proximal thoracic curve helps to prevent postoperative cervical tilt in Lenke type 2 adolescent idiopathic scoliosis patients with right-elevated shoulder

BACKGROUND

To date, no study had reported the phenomenon of deteriorated postoperative cervical tilt in Lenke type 2 adolescent idiopathic scoliosis patients. The purpose of this study is to evaluate the cervical tilt in Lenke type 2 adolescent idiopathic scoliosis patients with right-elevated shoulder treated by either full fusion or partial/non fusion of the proximal thoracic curve.

METHODS

A total of 30 Lenke type 2 AIS patients with preoperative right-elevated shoulder underwent posterior spinal instrumentation from 2009 to 2011 were included in this study. All the subjects were divided into 2 groups according to the selection of upper instrumented vertebra. There were 14 cases proximally fused to T1 or T2 (Group A) and 16 cases proximally fused to T3 or below (Group B). Both standing anteroposterior and sagittal X-ray films of the spine obtained preoperatively, one week after the operation, and at a minimum of two-year follow-up were analyzed with respect to the following parameters: cervical tilt, T1 tilt, proximal thoracic Cobb angle, main thoracic Cobb angle, apical vertebral translation of proximal thoracic curve, apical vertebral translation of main thoracic curve, radiographic shoulder height, cervical lordosis, proximal thoracic kyphosis and main thoracic kyphosis.

RESULTS

Most (83.3%) of the patients in these two groups gained satisfactory shoulder balance after surgery. However, the cervical tilt significantly improved in group A (p < 0.001) but deteriorated in group B (p < 0.001). In group A, the decrease of cervical tilt significantly positively correlated with that of T1 tilt (p < 0.001). In group B, the increase of cervical tilt significantly positively correlated with both the increase of T1 tilt (p < 0.001) and the increase of apical vertebral translation of proximal thoracic curve (p < 0.05).

CONCLUSIONS

Lenke type 2 AIS patients with right-elevated shoulder gain improved shoulder but deteriorated cervical tilt after partial/non fusion of proximal thoracic curve. Full fusion of proximal thoracic curve helps to prevent the residual cervical tilt in these patients.

Computer Assisted Cobb Angle Measurements: A novel algorithm

BACKGROUND

The standard for evaluating scoliosis is PA radiographs using Cobb angle to measure curve magnitude. Newer PACS systems allow easier Cobb angle calculations, but have not improved inter/intra observer precision of measurement. Cobb angle and its progression are important to determine treatment; therefore, angle variability is not optimal. This study seeks to demonstrate that a performance equivalent to that achieved in the manual method is possible using a novel computer algorithm with limited user input. The authors compared Cobb angles from predetermined spinal levels in the average attending score versus the computer assisted approach.

METHODS

Retrospective analysis of PA radiographs from 58 patients previously evaluated for scoliosis was collected. Predesignated spinal levels (e.g., T2-T10) were assigned for different curves and calculated by Cobb method. Four spine surgeons evaluated these Cobb angles. Their average scores were measured and compared to formulated values using the novel computer-based algorithm. Literature reports inter-observer reliability is 6.3-7.2degrees. Limits of accuracy were set at 5 degrees of average orthopedic surgeons' score.

RESULTS

The computer-based algorithm calculated Cobb angles within 5 degrees of orthopedic surgeons' average with a standard deviation of 3.2 degrees. This result was based on a 95% confidence interval with p values <0.001. The computer algorithm was plotted against average angle determined by the surgeons, with individual determinations and linear regression (r² =0.90). The average difference between surgeons' measures and computer algorithm was 0.4 degrees(SD= 3.2degrees, n=79). There was a tendency for the computer algorithm program to overestimate the angle at larger angles, but difference was small with r² = 0.09.

CONCLUSIONS

Our study showed the novel computer based algorithm was an efficient and reliable method to assess scoliotic curvature in the coronal plane with the possibility of expediting clinic visits, ensuring reliability of calculation and decreasing patient exposure to radiation. Level of Evidence: III.

A Comparative Study of Sagittal Balance in Patients with Neuromuscular Scoliosis

OBJECTIVES:

Spinopelvic alignment has been associated with improved quality of life in patients with vertebral deformities, and it helps to compensate for imbalances in gait. Although surgical treatment of scoliosis in patients with neuromuscular spinal deformities promotes correction of coronal scoliotic deformities, it remains poorly established whether this results in large changes in sagittal balance parameters in this specific population. The objective of this study is to compare these parameters before and after the current procedure under the hypothesis is that there is no significant modification.

METHODS:

Sampling included all records of patients with neuromuscular scoliosis with adequate radiographic records treated at Institute of Orthopedics and Traumatology of Clinics Hospital of University of São Paulo (IOT-HCFMUSP) from January 2009 to December 2013. Parameters analyzed were incidence, sacral inclination, pelvic tilt, lumbar lordosis, thoracic kyphosis, spinosacral angle, spinal inclination and spinopelvic inclination obtained using the iSite-Philips digital display system with Surgimap and a validated method for digital measurements of scoliosis radiographs. Comparison between the pre- and post-operative conditions involved means and standard deviations and the t-test.

RESULTS:

Based on 101 medical records only, 16 patients met the inclusion criteria for this study, including 7 males and 9 females, with an age range of 9-20 and a mean age of 12.9±3.06; 14 were diagnosed with cerebral palsy. No significant differences were found between pre and postoperative parameters.

CONCLUSIONS:

Despite correction of coronal scoliotic deformity in patients with neuromuscular deformities, there were no changes in spinopelvic alignment parameters in the group studied.

Analysis of Sagittal Parameters in Patients Undergoing One- or Two-Level Closing Wedge Osteotomy for Correcting Thoracolumbar Kyphosis Secondary to Ankylosing Spondylitis

STUDY DESIGN

Retrospective analysis of clinical records.

OBJECTIVE

To assess and compare the improvement in sagittal balance after one- or two-level closing wedge osteotomy for correcting thoracolumbar kyphosis secondary to ankylosing spondylitis (AS).

SUMMARY OF BACKGROUND DATA

Closing wedge osteotomy represents a common approach to correct kyphosis in AS. Although several reports have described the outcomes of one- or two-level closing wedge osteotomy in terms of sagittal parameters, data comparing the outcomes of these procedures are scarce.

METHODS

Between January 2010 and December 2014, 22 patients with AS underwent closing wedge osteotomy (one-level, 12 patients; two-level, 10 patients) for correcting thoracolumbar kyphosis (mean follow-up, 24.8 months; range, 12-60 months). Preoperative and postoperative chin-brow vertical angle, and the sagittal parameters of the vertebral osteotomy segment were documented and compared. Perioperative and postoperative complications were also recorded.

RESULTS

The chin-brow vertical angle improved significantly, from 55.0° ± 27.3° to 4.7° ± 4.9° and from 38.2° ± 14.9° to 3.2° ± 5.4° in the one-level and two-level groups, respectively. The total correction (thoracic kyphosis and lumbar lordosis) was 32.8° ± 18.2° and 53.7° ± 9.4° in the one-level and two-level groups, respectively. No death, complete paralysis, or vascular complications occurred during the procedure, but cerebrospinal fluid leak was noted in one and two patients from the one-level and two-level groups, respectively. A distal pedicle screw adjacent to the osteotomy segment became loose during surgery in one patient (one-level group). Postoperatively, no transient neurological deficit, infection, delay union, or loosening or breaking of the internal fixation devices was observed. Osteotomy site fusion was achieved in all patients, and the Oswestry Disability Index scores improved significantly.

CONCLUSION

Closing wedge osteotomy is effective and safe for correcting thoracolumbar kyphosis in patients with AS. Significant correction and improvement in all sagittal parameters were noted in both groups, but two-level closing wedge osteotomy provided better correction.

LEVEL OF EVIDENCE

3.

Reliability analysis of Cobb measurement in degenerative lumbar scoliosis using endplate versus pedicle as bony landmarks

OBJECTIVES

Degenerative changes of endplates in older patients and tilting of vertebral body in lumbosacral lordosis could make an accurate identification of endplates for the Cobb measurement difficult. Pedicles have been proposed as alternative landmarks because they are usually better visualized, and offer similar clinical validity to the endplates. The objective of this study was to investigate the reliability of the pedicle method of Cobb measurement in degenerative lumbar scoliosis and compare it with the traditional endplate method.

METHODS

Two hundred and eighty-four radiographs of degenerative lumbar scoliosis were evaluated. The radiographs were classified into groups based on the patient's age (< 60 years, 60 to 80 years, and > 80 years), level of lower end vertebra (LEV) (LEV at L5, and LEV at or above L4), and curve severity (< 20°, 20° to 40°, and > 40°). Three observers independently measured the radiographs using the endplate and pedicle methods twice with an interval of 1 week. The intra- and interobserver reliabilities were calculated using intraclass correlation coefficients (ICC).

RESULTS

The intra- and interobserver ICC values were better for all observers in the > 80 years age group using the pedicle method. The intraobserver ICC values of pedicle method were also better in the LEV at L5 group, and the interobserver ICC values showed a slightly better consistency with the pedicle method. For patients with > 40° curves, the intraobserver ICC values for all observers as well as interobserver ICC values were better using the endplate method.

CONCLUSION

The reliabilities of the endplate and pedicle methods for degenerative lumbar scoliosis were both excellent. The pedicle method might be better in older patients (> 80 years) and those with LEV at L5; while the endplate method could have some strength in severe cases (> 40°).

The mechanisms underlying the variety of preoperative directionalities of shoulder tilting in adolescent idiopathic scoliosis patients with double thoracic curve

PURPOSE

Preoperative directionality of shoulder tilting seems to be independent of the radiographic features of proximal thoracic (PT) curve in adolescent idiopathic scoliosis (AIS) patients. To date, no study had investigated the mechanisms underlying the variety of preoperative directionalities of shoulder tilting in AIS patients. The purpose of this study was to evaluate the differences of radiographic features between Lenke type 2 (double thoracic curve) AIS patients with different preoperative directionalities of shoulder tilting.

METHODS

A total of 130 Lenke type 2 AIS patients were included in this study and were divided into two groups according to the value of radiographic shoulder height (RSH). There were 78 cases (71 females and 7 males) with RSH less than 0 cm in Group A and 52 cases (44 females and 8 males) with RSH equal to or more than 0 cm in Group B. Preoperative standing anteroposterior X-ray films of the spine were obtained in all these subjects and were analyzed with respect to the following parameters: T1 tilt, PT Cobb angle, main thoracic (MT) Cobb angle, the apical level of PT curve, the apical level of MT curve, and RSH. These parameters were compared between these two groups and the correlations between RSH and the other parameters were analyzed in all of these subjects.

RESULTS

No significant difference was found between these two groups with respect to PT Cobb angle or the apical level of PT curve (P > 0.05). The apical level of MT curve was significantly more proximal in Group A compared with Group B (P < 0.05). The MT Cobb angle was significantly larger in Group A compared with Group B (P < 0.05). Both the T1 tilt and the PT Cobb angle/MT Cobb angle ratio in Group A were significantly smaller than those in Group B (P < 0.05). The RSH was positively associated with T1 tilt, the apical level of MT curve, and the PT Cobb angle/MT Cobb angle ratio, but was negatively associated with MT Cobb angle (P < 0.05).

CONCLUSION

The directionality of shoulder tilting is diverse in Lenke type 2 AIS patients. The preoperative directionality of shoulder mainly depends on the profile of MT curve rather than that of PT curve. The RSH should be carefully evaluated before making a surgical plan in these patients.

MRI May Serve as a Valid Alternative to Standing Radiography in Evaluating the Sagittal Alignment of the Upper Thoracic Spine

STUDY DESIGN

This study is of a retrospective radiographic design.

OBJECTIVE

The objective of the study was to compare supine magnetic resonance images (MRI) with standing x-ray scanning in the evaluation of the sagittal alignment of the upper thoracic spine.

SUMMARY OF BACKGROUND DATA

X-ray films have been reported to be inaccurate in evaluating the proximal thoracic sagittal alignment because of poor visibility of the upper thoracic region. Previous studies have demonstrated the feasibility of supine MRI in evaluating spinal deformities in the coronal plane. However, no study has addressed the use of MRI for evaluating the sagittal alignment of the upper thoracic region.

METHODS

Ninety-six adolescents with idiopathic thoracolumbar/lumbar scoliosis were enrolled. The visibility of the upper thoracic spine landmarks from C7 to T6 in the lateral standing x-ray films was first graded. For patients with moderate or good clarity of the landmarks of each vertebra from C7 to T6 on x-ray films, the vertebral sagittal angles from T1 to T5 and the angle of T2-T5 kyphosis were measured by 3 observers on standing x-ray films and supine MRI images, respectively. Intraclass correlation coefficients were used to determine the intraobserver, interobserver, and method reliability. The paired t test was performed to compare the measurements between the 2 methods.

RESULTS

The visibility of the upper thoracic region in x-ray films was generally unsatisfactory, especially for T1 and T2, whereas all the vertebrae were clear in MRI images. Only 50 patients' x-ray films were graded as moderate or good visibility in the upper thoracic spine. Measurements on MRI images gave excellent intraobserver and interobserver reliability (0.914-0.924 and 0.838-0.920, respectively), which were better than that on x-ray films (0.767-0.891 and 0.713-0.883, respectively). No significant difference was found between the 2 modalities in terms of sagittal angles of T3, T4, and T5 (P=0.680, 0.595, and 0.239, respectively) and T2-T5 kyphosis (P=0.105).

CONCLUSIONS

With excellent measurement reproducibility, a supine MRI image may serve as a valid alternative to a standing x-ray film for the measurement for T3, T4, and T5 sagittal angles and for the evaluation of upper thoracic kyphosis.

Assessment of Vertebral Curves Using the Manual Post-It Technique

STUDY DESIGN

A prospective study of a new technique.

OBJECTIVE

The aims of this study were to report a manual technique for measuring vertebral curves on digital spine radiographs, and to assess the agreement of this technique with that of digital software for measuring vertebral curves.

SUMMARY OF BACKGROUND DATA

Modern picture archiving and communication systems (PACS) typically include software for evaluating radiographic measurements. However, in the outpatient spine setting, patients may present with radiographs stored on a physical disc, which may not include software for measuring vertebral curves. Certain smartphone applications may be used to determine curve magnitude; however, the need exists for an accurate manual technique to measure vertebral curves on digital radiographs in the absence of available analytic software or smartphone technology.

METHODS

We prospectively reviewed anteroposterior and lateral spine radiographs of 24 spinal deformity patients. Two independent observers measured Cobb angles for: (1) the major coronal curve; (2) the thoracic kyphosis (T2-T12); and (3) the lumbar lordosis (T12-S1). Measurements were made: (1) digitally using our institution's PACS; and (2) by a manual technique, which involves placement of an adhesive Post-It note directly on the computer screen, transcribing the angle onto the Post-It note with a pencil, and measuring the angle with a handheld goniometer. Intraclass correlation coefficients (ICCs) were calculated to determine the agreement between the 2 methods.

RESULTS

For both observers, the agreement between the digital PACS and manual Post-It techniques was graded as excellent for both coronal and sagittal plane curves (all ICCs>0.9). Interobserver reliability between the 2 observers was also graded as excellent for both the PACS and Post-It techniques (all ICCs>0.9).

CONCLUSIONS

The Post-It technique for measuring Cobb angles demonstrated excellent agreement with the PACS system in our series of spinal deformity patients. Curves on digital radiographs can be accurately measured using a convenient manual technique.

The influence of body image on surgical decisions in adolescent idiopathic scoliosis patients

OBJECTIVES:

The objective of this study was to evaluate whether the severity of deformities in patients with adolescent idiopathic scoliosis contributes to patients' decision regarding whether to undergo an operation.

METHODS:

We evaluated body image factors in adolescent idiopathic scoliosis patients. We evaluated the magnitude of the main scoliotic curve, gibbosity (magnitude and location), shoulder height asymmetry and patient's age. We analyzed the correlation of these data with the number of years the patient was willing to trade for surgery, as measured by the time-trade-off method.

RESULTS:

A total of 52 patients were studied. We did not find a correlation between any of the parameters that were studied and the number of years that the patient would trade for the surgery.

CONCLUSIONS:

The magnitude of body deformities in patients with adolescent idiopathic scoliosis does not interfere with the decision to undertake surgical treatment.

Use of the smartphone for end vertebra selection in scoliosis

Objectives

The aim of our study was to develop a smartphone-aided end vertebra selection method and to investigate its effectiveness in Cobb angle measurement.

Methods

Twenty-nine adolescent idiopathic scoliosis patients' pre-operative posteroanterior scoliosis radiographs were used for end vertebra selection and Cobb angle measurement by standard method and smartphone-aided method. Measurements were performed by 7 examiners. The intraclass correlation coefficient was used to analyze selection and measurement reliability. Summary statistics of variance calculations were used to provide 95% prediction limits for the error in Cobb angle measurements. A paired 2-tailed t test was used to analyze end vertebra selection differences.

Results

Mean absolute Cobb angle difference was 3.6° for the manual method and 1.9° for the smartphone-aided method. Both intraobserver and interobserver reliability were found excellent in manual and smartphone set for Cobb angle measurement. Both intraobserver and interobserver reliability were found excellent in manual and smartphone set for end vertebra selection. But reliability values of manual set were lower than smartphone. Two observers selected significantly different end vertebra in their repeated selections for manual method.

Conclusion

Smartphone-aided method for end vertebra selection and Cobb angle measurement showed excellent reliability. We can expect a reduction in measurement error rates with the widespread use of this method in clinical practice.

Level of evidence

Level III, Diagnostic study

Reproducibility of thoracic kyphosis measurements in patients with adolescent idiopathic scoliosis

Background

Current surgical treatment for adolescent idiopathic scoliosis (AIS) involves correction in both the coronal and sagittal plane, and thorough assessment of these parameters is essential for evaluation of surgical results. However, various definitions of thoracic kyphosis (TK) have been proposed, and the intra- and inter-rater reproducibility of these measures has not been determined. As such, the purpose of the current study was to determine the intra- and inter-rater reproducibility of several TK measurements used in the assessment of AIS.

Methods

Twenty patients (90% females) surgically treated for AIS with alternate-level pedicle screw fixation were included in the study. Three raters independently evaluated pre- and postoperative standing lateral plain radiographs. For each radiograph, several definitions of TK were measured as well as L1–S1 and nonfixed lumbar lordosis. All variables were measured twice 14 days apart, and a mixed effects model was used to determine the repeatability coefficient (RC), which is a measure of the agreement between repeated measurements. Also, the intra- and inter-rater intra-class correlation coefficient (ICC) was determined as a measure of reliability.

Results

Preoperative median Cobb angle was 58° (range 41°–86°), and median surgical curve correction was 68% (range 49–87%). Overall intra-rater RC was highest for T2–T12 and nonfixed TK (11°) and lowest for T4–T12 and T5–T12 (8°). Inter-rater RC was highest for T1–T12, T1-nonfixed, and nonfixed TK (13°) and lowest for T5–T12 (9°). Agreement varied substantially between pre- and postoperative radiographs. Inter-rater ICC was highest for T4–T12 (0.92; 95% CI 0.88–0.95) and T5–T12 (0.92; 95% CI 0.88–0.95) and lowest for T1-nonfixed (0.80; 95% CI 0.72–0.88).

Conclusions

Considerable variation for all TK measurements was noted. Intra- and inter-rater reproducibility was best for T4–T12 and T5–T12. Future studies should consider adopting a relevant minimum difference as a limit for true change in TK.

Electronic supplementary material

The online version of this article (doi:10.1186/s13013-017-0112-4) contains supplementary material, which is available to authorized users.

CHANGES IN THE SAGITTAL BALANCE IN CONGENITAL SCOLIOSIS CORRECTION SURGERY

ABSTRACT Objective: This study aimed to determine whether surgery leads to changes in sagittal balance in patients with congenital scoliosis. Methods: We retrospectively reviewed all cases of scoliosis operated in a tertiary hospital between January 2009 and January 2013. In all cases the deformity in the coronal and sagittal planes, kyphosis, and lordosis were measured, using the Cobb method, and spinopelvic parameters: pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT). Results A hundred and eleven medical records were analyzed, but the sample resulted in 10 patients, six of whom were females (60%). The average age was 13.4 years. In the comparative analysis between pre and postoperative, only the coronal deformity (12.37; CI 95% [7.88-16.86]; p<0.001), the sagittal deformity (12.71; CI 95% [4.21-21.22]; p=0.011), and the lumbar lordosis (9.9; CI 95% [0.38-19.42]; p=0.043) showed significant change. Conclusion: There was no change in the spinopelvic parameters of patients with congenital scoliosis undergoing surgery at IOF-FMUSP between 2009 and 2013; however, it was observed decrease in lumbar lordosis, and deformity angle in the sagittal and coronal planes.

Compensatory modulation for severe global sagittal imbalance: significance of cervical compensation on quality of life in thoracolumbar kyphosis secondary to ankylosing spondylitis

PURPOSE

To investigate the cervical compensation pattern and to clarify relationships between cervical compensation and quality of life (QOL) in ankylosing spondylitis (AS) patients with thoracolumbar kyphosis.

METHODS

A cross-sectional study of consecutive AS patients with thoracolumbar kyphosis was performed. Forty-four patients with hyperlordotic cervical spine were assigned to group A and sixteen with kyphotic cervical spine in group B. Sagittal parameters were measured and compared, including T1 slope, cervical lordosis (CL), cervical sagittal vertical axis (C-SVA), global SVA and global kyphosis (GK). Independent factors for cervical compensation were identified. To exclude confounding variables while comparing QOL between patients with hyperlordotic and kyphotic cervical spine, 31 patients were selected as group A-1, similar to 13 patients in group B-1 in the distribution of matching variables such as age, gender, course of disease, GK, global SVA and radiographic progression assessment for AS. The QOL was assessed by Neck Disability Index (NDI) and other indices.

RESULTS

Mean C-SVA was significantly lower in group A than in group B, whereas mean T1 slope, global SVA and GK were significantly larger in group A. T1 slope (36.0 %) was the independent factor for CL. T1 slope was correlated with CL, GK and global SVA in group A. Group A-1 showed lower NDI score. CL (59.6 %) independently affects NDI.

CONCLUSION

Notable cervical compensation exists in AS patients with thoracolumbar kyphosis. The cervical compensation responsive to global imbalance was mediated by T1 slope. AS patients with hyperlordotic cervical spine present with better QOL than patients with kyphotic cervical spine.

Early weaning in idiopathic scoliosis

Background

Many years of bracing represent a burden to the patients. Early weaning may be the result of poor compliance, but may also be planned in patients with a long expected treatment time and a reduced stable primary curve during bracing. The aim of the present cohort study was to compare curve size, health related quality of life and surgical rates at long-term follow-up after ordinary bracing, planned and unplanned early weaning.

Methods

Three hundred eighty-one patients (353 girls/28 boys) with late-onset juvenile (n = 30) and adolescent (n = 351) idiopathic scoliosis and a mean primary major curve of 33.1 (range 20–57)° were treated with Boston brace and followed prospectively.

Results

Ordinary brace treatment was completed in 290 (76 %) patients, planned early weaning at bone age <14 years in 59 (16 %), and unplanned early weaning in 32 (8 %), while 14 (5 %), 1 (2 %), and 12 (38 %) had surgery, respectively. Forty-eight (81 %) of the patients had a primary curve ≤ 25° at planned early weaning. Six-teen (27 %) of those who had planned early weaning, resumed bracing after a mean time of 2.0 years. The mean curve size at long-term follow-up in average 23.4 years after weaning, was smaller (p < 0.001) in patients with planned early weaning (25.1°) compared with ordinary bracing (34.0°) and unplanned early weaning (34.8°). Patient satisfaction and self-image at long-term was better in the planned early weaning group (p < 0.05), but differences were small.

Conclusion

The benefit of planned early weaning was the shortened bracing time and good clinical results. This procedure may be attempted if curve reduction is stable over time and the primary curve is 25° or less in patients with several years of expected bracing. The patients should be monitored carefully and regularly at 4-6 months intervals until maturity, and a new brace should be prepared if the curve increases significantly.

The Validity of Rasterstereography: A Systematic Review

To investigate and monitor the progression of scoliosis and other spinal deformities in patients following idiopathic scoliosis (IS), non-invasive and radiation-free techniques are recommended because of the need for repeated radiographs. In a clinical setting, spine parameters can be quickly, cheaply and easily assessed using rasterstereography (RS). To assess the validity of the radiation-free technique RS based on surface topography compared with radiographs. MEDLINE, the Cochrane Library and EMBASE were systematically searched for studies which investigate the validity of rasterstereography compared with x-ray measurements. Studies published between January 1, 1990 and July 31, 2013 in English, German and French were included. Studies dealing with magnetic resonance imaging were excluded. Twelve studies with 570 patients were included; these articles were published between 1990 and 2013. The majority of studies investigated patients with IS, but other spinal pathologies included were thoracic hyperkyphosis and Scheuermann’s disease. With regard to the quality assessment criteria for the included studies, three out of twelve studies were evaluated using a twelve point scale and two used a scale with eleven points. We conclude that RS facilitates clinical practice by analysing the spinal column. It is completely radiation-free and could help to monitor scoliosis progression.

Radiological Outcomes in Adolescent Idiopathic Scoliosis Patients More Than 22 Years After Treatment

STUDY DESIGN

Longitudinal cohort.

OBJECTIVES

To evaluate the long-term radiologic outcomes in adolescent idiopathic scoliosis (AIS) patients more than 22 years after treatment.

SUMMARY OF BACKGROUND DATA

Although treatment for AIS is prophylactic and is aimed at preventing curve progression, very few studies report long-term outcomes of treatment.

METHODS

AIS patients treated with Boston brace or posterior spinal fusion (PSF) with Harrington-dorso-transverse traction (DTT) instrumentation from 1983 to 1990 were requested to return to clinic. Subsequently, 36-inch standing radiographs were obtained after patient consent. Cobb angles were compared with pretreatment and immediate posttreatment radiographs. Any evidence of adjacent-level disease or local kyphosis was also noted.

RESULTS

One hundred fifty-nine (78%) of 219 patients were available for follow-up, 66 braced and 93 surgical. There were 85 females with an average age at surgery of 14.3 years and an average age at follow-up of 37.6 years. The mean length of follow-up was 24.5 years (range, 22-30 years). There was a statistically significant curve progression of 2.9° in the PSF group. There was a greater degree of curve progression in the braced group (5.5°), but this was not statistically significant. Proximal segment degeneration was seen in 8 (5%), 2 in the brace cohort and 6 in the PSF cohort. Distal segment degeneration was seen in 26 (16%) patients, 4 treated with brace and 22 treated with PSF. No patient developed proximal junction kyphosis. Three patients in the PSF cohort required additional surgery for distal adding-on. Four patients had a noncontiguous L5-S1 fusion, three from the PSF cohort and one from the braced cohort.

CONCLUSION

In this cohort with an average follow-up of 24.5 years, with 78% available for follow-up, both the braced and surgically treated patients had a very small degree of curve progression, with a small incidence of distal segment degeneration and reoperation.

LEVEL OF EVIDENCE

III.

Reliability and accuracy of ultrasound measurements with and without the aid of previous radiographs in adolescent idiopathic scoliosis (AIS)

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.