Assessing progressive changes in axial plane vertebral deformity in adolescent idiopathic scoliosis using sequential magnetic resonance imaging.

PURPOSE: To understand how the axial plane deformity contributes to progression of the three-dimensional spinal deformity of Adolescent Idiopathic Scoliosis (AIS), with a main thoracic curve type, using a series of sequential magnetic resonance images (MRI). METHODS: Twenty-seven AIS patients (at scan 1: mean 12.4 years (± 1.5), mean Cobb angle 29.1°(± 8.8°)) had 3 MRI scans (T4-L1) performed at intervals of mean 0.7 years (± 0.4). The outer profile of the superior and inferior endplates were traced on a reformatted axial image using ImageJ (NIH). Endplate AVR, and intravertebral rotation (IVR), defined as the difference between superior and inferior endplate AVR, was calculated for each vertebral level. RESULTS: For all patients and scans, the mean AVR was greatest at the curve apex, with AVR diminishing in a caudal and cephalic direction from the apex. At scan 3 the mean apical AVR was 15.1°(± 4.6°) with a mean change in apical AVR between MRI 1 and 3 of 2.7°(± 2.9°). The increase in standing height between MRI 1 and 3 was mean 7.4 cm (± 4.6). Linear regression showed a positive correlation between apical AVR and Cobb angle (R2 = 0.57, P < 0.001), and a positive correlation between apical AVR and rib hump (R2 = 0.54, p < 0.001). The mean change in IVR was greater 3 vertebral levels cephalic and caudal to the apex (1.4°(± 4.1°) and 1.2°(± 2.0°), respectively), compared to the apex (0.4°(± 3.1°)). CONCLUSIONS: AVR increased, during curve progression, most markedly at the curve apex. The greatest IVR was observed at the periapical levels, with the apex by contrast having only a modest degree of rotation, suggesting the periapical vertebral levels of the scoliosis deformity may be a significant driver in the progression of AIS.

Reliability of the axial vertebral rotation measurements of adolescent idiopathic scoliosis using the center of lamina method on ultrasound images: in vitro and in vivo study.

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.

Correlation of transverse rotation of the spine using surface topography and 3D reconstructive radiography in children with idiopathic scoliosis.

PURPOSE: The relationship between axial surface rotation (ASR) measured by surface topography (ST) and axial vertebral rotation (AVR) measured by radiography in the transverse plane is not well defined. This study aimed to: (1) quantify ASR and AVR patterns and their magnitudes from T1 to L5; (2) determine the correlation or agreement between the ASR and AVR; and (3) investigate the relationship between axial rotation differences (ASR-AVR) and major Cobb angle. METHODS: This is a retrospective study evaluating patients (age 8-18) with IS or spinal asymmetry with both radiographic and ST measurements. Demographics, descriptive analysis, and correlations and agreements between ASR and AVR were evaluated. A piecewise linear regression model was further created to relate rotational differences to Cobb angle. RESULTS: Fifty-two subjects met inclusion criteria. Mean age was 14.1 ± 1.7 and 39 (75%) were female. Looking at patterns, AVR had maximal rotation at T8, while ASR had maximal rotation at T11 (r = 0.35, P = .006). Cobb angle was 24.1° ± 13.3° with AVR of - 1° ± 4.6° and scoliotic angle was 20.9° ± 11.5° with ASR of - 2.3° ± 6.6°. (ASR-AVR) vs Cobb angle was found to be very weakly correlated with a curve of less than 38.8° (r = 0.15, P = .001). CONCLUSION: Our preliminary findings support that ASR measured by ST has a weak correlation with estimation of AVR by 3D radiographic reconstruction. This correlation may further help us to understand the application of transverse rotation in some clinical scenarios such as specific casting manipulation, padding mechanism in brace, and surgical correction of rib deformity.

Initial evaluation of the relationship between maximal axial vertebra rotation and the rotation deformity in adolescent idiopathic scoliosis.

PURPOSE: This study evaluated the relationship between maximal axial vertebra rotation (maxAVR) and other clinical and radiological indexes, compared to apical vertebra rotation (AVR) in idiopathic adolescent scoliosis (AIS). METHODS: Forty consecutive patients of AIS with Cobb angle of major curve > 40° were included. They were scanned by an EOS imaging system and had trunk rotational angle (TRA) measured by scoliometer. The correlation between variables was assessed using Pearson's correlation coefficient and loaded onto a meta-analysis model. RESULTS: There were (34 girls and 6 boys) with an average age of 13.8 ± 1.6 years. AVR was maxAVR in only 47.5% (19/40) cases of the major curves and 42.3% (11/26) cases of the minor curves. The correlation between maxAVR and TRA was significantly higher than the correlation between AVR and TRA for the MT curves (p = 0.0001) and TL/L curves (p = 0.0001). On multivariate regression analysis, the magnitude of maxAVR showed a significant correlation with TRA (p = 0.0002), Cobb angle (p = 0.001), and coronal deformity angular ratio (C-DAR) (p = 0.027). CONCLUSIONS: The apical vertebra was not the most rotated in most cases. The correlation between maxAVR and TRA was significantly higher than the correlation between AVR and TRA. Moreover, the maxAVR was multivariately related to TRA, Cobb angle, and C-DAR. LEVEL OF EVIDENCE: Level II, diagnostic.

Scoliosis Management through Apps and Software Tools.

Background: Scoliosis is curvature of the spine, often found in adolescents, which can impact on quality of life. Generally, scoliosis is diagnosed by measuring the Cobb angle, which represents the gold standard for scoliosis grade quantification. Commonly, scoliosis evaluation is conducted in person by medical professionals using traditional methods (i.e., involving a scoliometer and/or X-ray radiographs). In recent years, as has happened in various medicine disciplines, it is possible also in orthopedics to observe the spread of Information and Communications Technology (ICT) solutions (i.e., software-based approaches). As an example, smartphone applications (apps) and web-based applications may help the doctors in screening and monitoring scoliosis, thereby reducing the number of in-person visits. Objectives: This paper aims to provide an overview of the main features of the most popular scoliosis ICT tools, i.e., apps and web-based applications for scoliosis diagnosis, screening, and monitoring. Several apps are assessed and compared with the aim of providing a valid starting point for doctors and patients in their choice of software-based tools. Benefits for the patients may be: reducing the number of visits to the doctor, self-monitoring of scoliosis. Benefits for the doctors may be: monitoring the scoliosis progression over time, managing several patients in a remote way, mining the data of several patients for evaluating different therapeutic or exercise prescriptions. Materials and Methods: We first propose a methodology for the evaluation of scoliosis apps in which five macro-categories are considered: (i) technological aspects (e.g., available sensors, how angles are measured); (ii) the type of measurements (e.g., Cobb angle, angle of trunk rotation, axial vertebral rotation); (iii) availability (e.g., app store and eventual fee to pay); (iv) the functions offered to the user (e.g., posture monitoring, exercise prescription); (v) overall evaluation (e.g., pros and cons, usability). Then, six apps and one web-based application are described and evaluated using this methodology. Results: The results for assessment of scoliosis apps are shown in a tabular format for ease of understanding and intuitive comparison, which can help the doctors, specialists, and families in their choice of scoliosis apps. Conclusions: The use of ICT solutions for spinal curvature assessment and monitoring brings several advantages to both patients and orthopedics specialists. Six scoliosis apps and one web-based application are evaluated, and a guideline for their selection is provided.

Posterior Multisegment Apical Convex plus Concave Intervertebral Release Combined with Posterior Column Osteotomy for the Treatment of Rigid Thoracic/Thoracolumbar Scoliosis.

BACKGROUND: Intervertebral release (IVR) in the apical region is critical for full release of a rigid spine. Previous studies have mainly reported IVR techniques using an anterior approach or posterior apical convex IVR. We first report the surgical procedure of posterior multisegment apical convex plus concave IVR combined with posterior column osteotomy (PCO) for treating rigid thoracic/thoracolumbar scoliosis. METHODS: This study retrospectively analyzed clinical, radiologic outcomes and technique notes of 18 patients with rigid scoliosis treated with posterior multisegment convex plus concave IVR combined with PCO. RESULTS: The preoperative, postoperative, and final follow-up mean sagittal Cobb angles of the main curve were 75.2° (58.7°-110.2°), 18.4° (9°-35.1°), and 19.0° (8.2°-36.3°), respectively. The mean correction rate was 75.3% (66.7%-86.7%). In cases of thoracolumbar kyphosis, the preoperative, postoperative, and final follow-up mean sagittal Cobb angles were 45.7° (40.5°-52.6°), 18.8° (10.2°-27.5°), and 19.8° (11.1°-29°), respectively. The mean correction rate was 57% (42.1%-72.6%). The mean axial vertebral rotation (AVR) in the IVR region was 24.4° (14.3°-46.3°) preoperatively and was corrected to 10.9° (10.9°-26.6°) postoperatively. The mean correction rate for AVR was 55.9% (41.1%-78.6%). The coronal and sagittal Cobb angles and AVR postoperatively were significantly lower than those preoperatively (P < 0.001). This case series reported 2 cases of pleural effusion and 1 case of wound infection. CONCLUSIONS: Single posterior multilevel apical convex plus concave IVR combined with PCO is a safe and effective surgical method for treating rigid thoracic/thoracolumbar scoliosis that does not need 3-column osteotomy.

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.

Automatic measurement of axial vertebral rotation in 3D vertebral models.

Axial Vertebral Rotation (AVR) is a significant indicator of adolescent idiopathic scoliosis (AIS). A host of methods are provided to measure AVR on coronal plane radiographs or 3D vertebral model. This paper provides a method of automatic AVR measurement in 3D vertebral model that is based on point cloud segmentation neural network and the tip of the spinous process searching algorithm. An improved PointNet using multi-input and attention mechanism named Multi-Input PointNet is proposed, which can segment the upper and lower endplates of the vertebral model accurately to determine the transverse plane of vertebral model. An algorithm is developed to search the tip of the spinous process according to the special structure of vertebrae. AVR angle is measured automatically using the midline of vertebral model and projection ofy-axis on the transverse plane of vertebral model based on points obtained above. We compare automatic measurement results with manual measurement results on different vertebral models. The experiment shows that automatic results can achieve accuracy of manual measurement results and the correlation coefficient of them is 0.986, proving our automatic AVR measurement method performs well.

Evaluating the Change in Axial Vertebral Rotation Following Thoracoscopic Anterior Scoliosis Surgery Using Low-Dose Computed Tomography.

BACKGROUND CONTEXT: In recent years, there has been increasing appreciation of the need to treat scoliosis as a three-dimensional deformity. PURPOSE: Assessment of surgical strategies and outcomes should consider not only the coronal plane correction but also derotation of the transverse plane deformity that can affect trunk appearance. STUDY DESIGN: This study included a cohort of 29 female adolescent idiopathic scoliosis patients who received thoracoscopic single rod anterior fusion (TASF) surgery. This study used pre- and postoperative low-dose computed tomographic (CT) scans to accurately measure apical axial vertebral rotation (AVR). METHODS: The pre- and postoperative values for clinically measured coronal Cobb correction and rib hump correction as well as AVR were compared to determine whether these values improved postoperatively. There are no conflicts of interest to report for authors of this investigation. RESULTS: As expected, statistically significant reductions in coronal Cobb angle (mean preoperative Cobb 51°, reducing to 24° at the two-year follow-up) and rib hump (mean preoperative rib hump 15°, reducing to 7° at two-year follow-up) were achieved. The mean reduction in apical AVR measured using CT was only 3° (mean preoperative AVR 16°, reducing to 13° at two-year follow-up), which was statistically but not clinically significant. Significant correlations were found between Cobb angle and rib hump, between Cobb angle and AVR, and between AVR and rib hump, suggesting that patients with greater coronal Cobb correction also achieve better derotation with this surgical procedure. CONCLUSIONS: The historical low-dose CT data set permitted detailed three-dimensional assessment of the deformity correction that is achieved using thoracoscopic anterior spinal fusion for progressive adolescent idiopathic scoliosis.

The radiographic method for evaluation of axial vertebral rotation - presentation of the new method.

The objective of this study is to present a new radiographic method for the assessment of vertebral rotation from an antero-posterior view of conventional X-rays which is sufficiently precise in comparison with radiographic methods presently used in clinical practice (methods of Nash-Moe and Perdriolle). This method is based on the properties of the geometric shape of vertebrae and their shared dimensional proportions. It means that the relation between vertebral body width and height doesn't change significantly within the entire thoracic and lumbar sections of the spine. In order to verify the method, we have constructed a special device for vertebral fixation. Subsequently, the X-ray pictures of individual human vertebrae with predefined rotation values (ranging from 0 degrees to 45 degrees by steps of 3 degrees) were radio-graphically measured and then compared with their actual axial rotation on the vertebral rotation device. All arithmetic averages correlate very closely with the actual values. The verification of axial vertebral rotation with the assistance of CT and MRI pictures of six scoliotic patients (in supine position) and the evaluation of axial vertebral rotation by both the new radiographic method and with the Perdriolle method proved the satisfactory accuracy of our method. The main advantage of the newly presented radiographic method is the uncomplicated measurement of vertebral rotation from AP projection of conventional X-ray pictures or from its printed copies. The gold standard of the new radiographic method is the evaluation of axial rotation of vertebrae to 30 degrees approximately and the shape of vertebral bodies without severe structural deformities. The new radiographic method seems to be suitable for use in clinical practice.