Assessment Of Adolescent Idiopathic Scoliosis Research Articles

The Prevalence of Hip Dysplasia on Radiographs for Adolescent Idiopathic Scoliosis.

During radiographic assessment of adolescent idiopathic scoliosis (AIS), upright images frequently capture the hip. The purpose of this study was to assess the prevalence of radiographic hip dysplasia on postero-anterior (PA) scoliosis radiographs, as defined as a lateral center edge angle (LCEA) ≤25 degrees. All patients with upright PA scoliosis radiographs over a one-year study period at a single tertiary academic medical center (2020 to 2021) were included in the study. Radiographs containing the hip joints were annotated by 3 reviewers for left and right LCEA, and triradiate cartilage (TRC) status. Inter-rater reliability was determined among the 3 reviewers. Two hundred fifty patients {500 hips, 75.6% female, median age 14 [interquartile range (IQR)=3]} had PA scoliosis radiographs that captured the hip, which qualified for analysis. Seventy-four hips (14.8%) demonstrated evidence of dysplasia (LCEA ≤25 deg) in 55/250 patients (22%). The median LCEA was significantly lower in the dysplastic hip cohort (23.9 deg, IQR=4.8 deg), compared with those without dysplasia (33 deg IQR=7.3 deg; P =0.001). A higher percentage of dysplastic hip patients were female than male (72.7% vs. 27.3%). Patients with bilateral dysplasia had a similar LCEA ( 22.9 deg) [to those with unilateral dysplasia (22.9 deg left, 23.9 deg right, P =0.689)]. In a cohort of 250 AIS patients, 22% demonstrated evidence of hip dysplasia, as defined as an LCEA ≤2 degrees. The dysplastic patients were more likely to be female. Screening for hip symptomatology in AIS patients may be of benefit, considering the frequency of radiographic hip dysplasia in this population. III. Type of Evidence: diagnostic.

Don't forget the pelvis: accounting for pelvic rotation in the preoperative assessment of adolescent idiopathic scoliosis.

Accurate radiographic assessment of adolescent idiopathic scoliosis (AIS) is crucial to achieving surgical correction, yet pelvic rotation may alter measurements. In Lenke Type 1/2 AIS patients, we conducted a pilot study to assess how pelvic rotation (i.e., the patient's position in the X-ray scanner) affected sagittal, coronal, and rotational measurements. A retrospective, pilot study of Type 1/2 AIS patients was undertaken. Demographics and three-dimensional (3D) SterEOS imaging were obtained. Measurements were compared between two scenarios: (I) radio plane-patient's natural position in the scanner; and (II) patient plane-patient's position after correcting to the transverse plane. Sagittal, coronal, and rotational measurements were compared, including: thoracic kyphosis (TK), lumbar lordosis (LL), main thoracic (MT) and thoracolumbar/lumbar (TL-L) Cobb, and apical vertebral rotation (AVR) in the proximal thoracic (PT), MT, and TL/L regions. Of 15 patients, average age was 15.7 years and 67% were female. Average baseline pelvic obliquity was 4.0 mm and pelvis rotation was 5.1°. Significant differences were seen between the radio vs. patient plane, respectively, in the following three measurements: TK, LL, and AVR: (I) TK (T1-12: 36.5° vs. 32.8°, P=0.003; T4-12: 28.4° vs. 22.7°, P<0.001); (II) LL (L1-5: 46.6° vs. 42.8°, P=0.002; L1-S1: 58.2° vs. 55.1°, P=0.003); (III) AVR (PT-AVR: 4.0° vs. 8.2°, P=0.003; MT-AVR: -14.8° vs. -10.5°, P=0.004; TL/L-AVR: (4.5° vs. 8.7°, P=0.003). No significant differences were seen in coronal cobb angles. After accounting for pelvic rotation, sagittal and rotational measurements were significantly altered. These results have implications for measurement accuracy, surgical decision-making, and postoperative monitoring.

Assessment of adolescent idiopathic scoliosis from body scanner image by finite element simulations.

Adolescent idiopathic scoliosis, is a three-dimensional spinal deformity characterized by lateral curvature and axial rotation around the vertical body axis of the spine, the cause of which is yet unknown. The fast progression entails regular clinical monitoring, including X-rays. Here we present an approach to evaluate scoliosis from the three-dimensional image of a patient’s torso, captured by an ionizing radiation free body scanner, in combination with a model of the ribcage and spine. A skeletal structure of the ribcage and vertebral column was modelled with computer aided designed software and was used as an initial structure for macroscopic finite element method simulations. The basic vertebral column model was created for an adult female in an upright position. The model was then used to simulate the patient specific scoliotic spine configurations. The simulations showed that a lateral translation of a vertebral body results in an effective axial rotation and could reproduce the spinal curvatures. The combined method of three-dimensional body scan and finite element model simulations thus provide quantitative anatomical information about the position, rotation and inclination of the thoracic and lumbar vertebrae within a three-dimensional torso. Furthermore, the simulations showed unequal distributions of stress and strain profiles across the intervertebral discs, due to their distortions, which might help to further understand the pathogenesis of scoliosis.

Automated vertebral landmarks and spinal curvature estimation using non-directional part affinity fields

Vertebral landmarks of posterior-anterior X-ray images can be used to determine the curvature of the spine, which is essential for the assessment of Adolescent Idiopathic Scoliosis. Recently, automatic methods are presented to assist the annotation process of vertebral landmarks. However, previous methods expect a fixed number of landmark outputs regardless of the occlusion and diversity in the X-ray images, which may result in inaccurate predictions in practical cases. The use of dense layers and fractional numbers with respect to image dimensions as landmark outputs also limited the accuracy of the prediction. In this paper, we propose a novel method based on fully convolutional architecture and non-directional part affinity fields to label arbitrary number of vertebral landmarks and keep track of the connection relations between them to compute the Cobb angles. Comparing with conventional methods which predict each landmark by dense layers directly, our method use image segmentation to predict the landmarks and their connection relationships with seven heatmap channels: four for corner landmarks and two for vertical center landmarks of each vertebra, and one for non-directional part affinity fields to express the pairing relations between left and right center landmarks. This design allows arbitrary number of landmarks as output, and reduces the impact of occluded landmark and malformed vertebrae on Cobb angles prediction. To evaluate our methods, mean squared error for landmarks and absolute percentage error for Cobb angles are tested. The results show that our method outperforms other methods on both metrics.

Preoperative assessment of idiopathic scoliosis in adolescent and young adult with three-dimensional T2-weighted spin-echo MRI.

To compare tridimensional (3D) T2-weighted spin-echo MRI and CT for minimal pedicle width measurements in the preoperative assessment of adolescent idiopathic scoliosis (AIS) in adolescent and young patients. A total of 22 adolescents/young patients suffering from AIS were retrospectively included. There were 18 females and 4 males with a mean age of 15.3±2.3 (SD) years (range: 11-21years). Preoperative lumbar spine MRI and CT examinations of the 22 patients were reviewed by two independent readers who measured the minimal width of 259 pedicles. Inter-reader agreement for CT and MRI was assessed using intra-class correlation coefficient (ICC). Intra-reader agreement and relative differences in measurements between MRI and CT were also assessed for each reader. Inter-reader agreement was excellent (ICC≥0.8) for both CT and MRI. Relative differences in measurements between CT and MRI was 10.3% for reader 1 and 9.4% for reader 2. 3D T2-weighted spin-echo MRI underestimates minimal pedicle width by only 9.4 - 10.3% compared to CT. 3D T2-weighted MRI appears as a valuable alternative to CT for preoperative measurements of vertebral pedicles in AIS.

Prediction of spinal curve progression in Adolescent Idiopathic Scoliosis using Random Forest regression

BackgroundThe progression of the spinal curve represents one of the major concerns in the assessment of Adolescent Idiopathic Scoliosis (AIS). The prediction of the shape of the spine from the first visit could guide the management of AIS and provide the right treatment to prevent curve progression. MethodIn this work, we propose a novel approach based on a statistical generative model to predict the shape variation of the spinal curve from the first visit. A spinal curve progression approach is learned using 3D spine models generated from retrospective biplanar X-rays. The prediction is performed every three months from the first visit, for a time lapse of one year and a half. An Independent Component Analysis (ICA) was computed to obtain Independent Components (ICs), which are used to describe the main directions of shape variations. A dataset of 3D shapes of 150 patients with AIS was employed to extract the ICs, which were used to train our approach. ResultsThe approach generated an estimation of the shape of the spine through time. The estimated shape differs from the real curvature by 1.83, 5.18, and 4.79° of Cobb angles in the proximal thoracic, main thoracic, and thoraco-lumbar lumbar sections, respectively. ConclusionsThe results obtained from our approach indicate that predictions based on ICs are very promising. ICA offers the means to identify the variation in the 3D space of the evolution of the shape of the spine. Another advantage of using ICs is that they can be visualized for interpretation.

Radiographic Resource Utilization in the Initial Referral and Evaluation of Patients With Adolescent Idiopathic Scoliosis.

The dangers of radiation exposure in children have been well studied, with assessment of adolescent idiopathic scoliosis (AIS) documented as having the potential for notable patient exposure. The purposes of this study were to evaluate a consecutive series of patients referred to a tertiary care pediatric hospital for AIS and to assess the type and quality of imaging obtained before referral for specialist evaluation. We performed a prospective study of consecutive patients referred over a 6-month period to a pediatric orthopaedic practice at a large, free-standing, urban children's hospital for evaluation of AIS. We assessed prereferral radiographic exposure, evaluating the utilization and adequacy of these radiographs. Of a total of 131 patients enrolled in the study, 79 had received radiographs before the visit; of these, only 59 patients (75%) brought the previously obtained radiographs to the specialist consultation, and 45 patients (76%) of this subset were found to be adequate for evaluation of AIS. Of the total cohort, 56 patients (43%) required repeat radiographs because of missing or inadequate radiographs. We found a large number of missing or inadequate radiographs, leading to repeat radiation exposure in this cohort. Improvements in the utilization of radiographs before orthopaedic referral could decrease unnecessary patient radiation exposure.

Key-Vertebral Screws Strategy for Main Thoracic Curve Correction in Patients With Adolescent Idiopathic Scoliosis.

The following study was a prospective radiographic and retrospective clinical data assessment of adolescent idiopathic scoliosis (AIS) patients who had undergone a key-vertebral screws strategy (KVSS) at a single institution, with a minimum of 2 years' follow-up. The aim of the study was to introduce the KVSS for the operative treatment of AIS of the main thoracic curve, and to address the role of the fulcrum-bending radiograph (FBR) in predicting the outcome of surgical management by this method. The application of multilevel pedicle screws for the main thoracic curve in AIS patients is popular in an effort to provide spinal stability, enhance fusion outcome, and provide optimal curve correction. However, with the application of pedicle screw also comes a potential risk for soft tissue and neural injury and increased health care costs. It remains unknown whether limited screw placement can provide proper curve correction without compromising patient outcome. A total of 17 consecutive patients with AIS extending to the main thoracic spine, who had undergone posterior fusion and fixation by the KVSS, a procedure in which screws are placed at important strategic points in the spine (ie, bilaterally at the upper and lower end segments of the fusion block, apical vertebra on the convex side, adjacent cephalad, and caudal screw placement on the concave side), at a single institution, with a minimum of 2 year' follow-up, were included. The assessment of preoperative standing posteroanterior and sagittal, FBR, and postoperative standing posteroanterior and sagittal plain radiographs were assessed in all patients. The flexibility of the curve as well as the fulcrum-bending correction index (FBCI) were calculated for all patients. Postoperatively, radiographs were assessed at the immediate (ie, 1 wk) and last follow-up. Clinical assessment entailed evaluation of patient demographics and the presence of any intraoperative or postoperative complications. The mean age at the time of surgery was 15.6 years. The mean follow-up was 39.8 months. The average FBR flexibility was 62.2%. The mean immediate curve correction was 71.2%, which did not differ in comparison with the last follow-up assessment (P>0.05). The mean immediate and last follow-up FBCIs were 119.3% and 112.5%, respectively (P=0.079). A significant negative correlation was found between immediate FBCI to that of the FBR curve flexibility (r=-0.706; P=0.002), which remained similar on the last follow-up (r=-0.681; P=0.003). Sagittal alignment did not significantly change from the immediate to last follow-up (P=0.163) Fusion was achieved in all patients. No instrumentation-related complications were noted. Key-vertebral screws strategy is a safe and cost-effective method for the surgical treatment of the main thoracic curve in AIS patients. Moreover, in the context of this strategy, the FBR may have some predictive utility in the correction of the main thoracic curve in AIS patients.

Bi-planar spinal stereoradiography of adolescent idiopathic scoliosis: considerations in 3D alignment and functional balance.

A prospective, cross-sectional study to determine the impact of arm position on the 3D spine and pelvic parameters and postural balance in adolescent idiopathic scoliosis. A total number of 37 adolescent idiopathic scoliosis patients were enrolled prospectively. Three arm positions, (1) 45° shoulder flexion with knuckles on clavicles, (2) 90° shoulder and elbow flexion with forearms and palms on the front wall, and (3) arms hanging on either side, were instructed to the cohort. Bi-planar low dose X-ray images of the spine and pelvis were registered in a stereoradiography system in the first and second arm positions. A pressure mat recorded the position of the center of pressure in each arm position. Spinal and pelvic parameters were measured for the cohort. Statistical analysis was performed to determine the agreement between the spinal and pelvic parameters and standing balance in different arm positions. Thoracic kyphosis, sacral slope, sagittal vertical axis, T1 tilt, and spinal height were significantly different between the knuckles onclavicle and forearms on the wall positions p<0.05. Significant differences were observed in the pressure distribution under the feet between the wall and freestanding positions. Bland-Altman plots determined disagreements between the first and second arm positions in clinical measurements and postural assessment of adolescent idiopathic scoliosis. The knuckles on clavicles position replicates the functional standing balance in AIS. Significant differences between the spinal and pelvic parameters suggest that the wall and clavicle arm positions should not be used interchangeably in AIS postural assessment. Diagnostic level II.

Imaging and three-dimensional analysis of adolescent idiopathic scoliosis

Three-dimensional (3D) spinal assessment requires transverse plane images in addition to the posteroanterior and lateral projections provided by traditional radiography. Computed tomography has allowed 3D spine visualization as serial transverse radiographic images are acquired. New biplanar slot scanners allow patients to stand during radiograph acquisition and provide superior quality images at lower radiation than traditional x-rays. The 3D measurements, which were never before attainable from planar radiographs, are semi-automatically calculated using commercial software. These images may be further processed to allow additional 3D analyses. In this article, historic and newer innovative approaches to 3D spine assessment of adolescent idiopathic scoliosis are presented.

Magnetic resonance of adolescent idiopathic scoliosis

AbstractThe following work aims to assess the feasibility of the magnetic resonance imaging (MRI) technique in the assessment of adolescent idiopathic scoliosis (AIS). At present, three modalities have proven to be worthy in this application. These are general radiography, computerised tomography (CT) and MRI. General radiography and CT have been the traditional methods, but carry some significant disadvantages including the use of ionising radiation. MRI, given its reliability, accuracy and lack of ionising radiation, has become the modality of choice for a wide range of applications including neurological and spinal conditions. In this study, measurements of axial images of the scoliotic spine were performed and inter‐observer variations were compared. The study, using MRI techniques, demonstrated favourable and promising results. In four of the measurements performed, absolutely no variations were found. The study also demonstrated a high positive correlation between curve data obtained from general radiography, and the curve data from those same patients using 3D coronal MRI imaging.