Surface topography asymmetry maps categorizing external deformity in scoliosis

The application of machine learning methods for predicting the progression of adolescent idiopathic scoliosis: a systematic review

Predicting curve progression during the initial visit is pivotal in the disease management of patients with adolescent idiopathic scoliosis (AIS)-identifying patients at high risk of progression is essential for timely and proactive interventions. Both radiological and clinical factors have been investigated as predictors of curve progression. With the evolution of machine learning technologies, the integration of multidimensional information now enables precise predictions of curve progression. This review focuses on the application of machine learning methods to predict AIS curve progression, analyzing 15 selected studies that utilize various machine learning models and the risk factors employed for predictions. Key findings indicate that machine learning models can provide higher precision in predictions compared to traditional methods, and their implementation could lead to more personalized patient management. However, due to the model interpretability and data complexity, more comprehensive and multi-center studies are needed to transition from research to clinical practice.

A Review of 3D Modalities Used for the Diagnosis of Scoliosis

Spine radiographs in the standing position are the recommended standard for diagnosing idiopathic scoliosis. Though the deformity exists in 3D, its diagnosis is currently carried out with the help of 2D radiographs due to the unavailability of an efficient, low-cost 3D alternative. Computed tomography (CT) and magnetic resonance imaging (MRI) are not suitable in this case, as they are obtained in the supine position. Research on 3D modelling of scoliotic spine began with multiplanar radiographs and later moved on to biplanar radiographs and finally a single radiograph. Nonetheless, modern advances in diagnostic imaging have the potential to preserve image quality and decrease radiation exposure. They include the DIERS formetric scanner system, the EOS imaging system, and ultrasonography. This review article briefly explains the technology behind each of these methods. They are compared with the standard imaging techniques. The DIERS system and ultrasonography are radiation free but have limitations with respect to the quality of the 3D model obtained. There is a need for 3D imaging technology with less or zero radiation exposure and that can produce a quality 3D model for diseases like adolescent idiopathic scoliosis. Accurate 3D models are crucial in clinical practice for diagnosis, planning surgery, patient follow-up examinations, biomechanical applications, and computer-assisted surgery.

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.

Effect of adding Schroth physiotherapeutic scoliosis specific exercises to standard care in adolescents with idiopathic scoliosis on posture assessed using surface topography: A secondary analysis of a Randomized Controlled Trial (RCT)

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is a three-dimensional structural asymmetry of the spine and trunk affecting 2-4% of adolescents. Standard treatment is observation, bracing, and surgery for small, moderate, and large curves, respectively. Schroth exercises aim to correct posture and reduce curve progression.

PURPOSE

This study aimed to determine the effect of Schroth exercises added to the standard care compared to standard care alone on torso asymmetry in AIS.

METHODS

In a randomized controlled trial (NCT01610908), 124 participants with AIS (age: 10-18, Cobb: 10°-45°, Risser: ≤3) were randomly assigned to the control (Standard care only) or Schroth (Standard care + Schroth treatment) group. Schroth treatment consisted of 1-hour weekly supervised sessions and 30-45 minutes of daily home exercises for six months. The control group received Schroth exercises in the last six months of the 1-year monitoring period. Markerless 3D surface topography assessed torso asymmetry measured by maximum deviation (MaxDev) and root mean square (RMS). Intention to treat linear mixed effects model analysis was compared to the per protocol analysis.

RESULTS

In the intention to treat analysis, the Schroth group (n = 63) had significantly larger decreased RMS (-1.2 mm, 95%CI [-1.5,-0.9]mm, p = 0.012) and MaxDev (-1.9mm, 95%CI [-2.4,-1.5]mm, p = 0.025) measurements compared to controls (n = 57) after six months of intervention. In the per protocol analysis (Schroth n = 39, control n = 36), the Schroth group also had a significantly larger decrease compared to the control in both the RMS (-1.0mm, 95%CI [-1.9, -0.2]mm, p = 0.013) and MaxDev measurements (-2.0mm, 95%CI [-3.3,-0.5]mm, p = 0.037). For the control group, both the intention to treat and per protocol analysis showed no difference in RMS and MaxDev in the last six months of Schroth intervention (p>0.5).

CONCLUSION

Schroth Exercise treatment added to standard care (observation or bracing) reduced asymmetry measurements in AIS. As expected, a greater effect was observed for participants who followed the prescribed exercise treatment per protocol.

Reliability of a New Digital Tool for Photographic Analysis in Quantifying Body Asymmetry in Scoliosis

Background: Advancements in non-ionizing methods for quantifying spinal deformities are crucial for assessing and monitoring scoliosis. In this study, we analyzed the observer variability of a newly developed digital tool for quantifying body asymmetry from clinical photographs. Methods: Prospective observational multicenter study. Initially, a digital tool was developed using image analysis software, calculating quantitative measures of body asymmetry. This tool was integrated into an online platform that exports data to a database. The tool calculated 10 parameters, including angles (shoulder height, axilla height, waist height, right and left waistline angles, and their difference) and surfaces of the left and right hemitrunks (shoulders, waists, pelvises, and total). Subsequently, an online training course on the tool was conducted for twelve observers not involved in its development (six research coordinators and six spine surgeons). Finally, 15 standardized back photographs of adolescent idiopathic scoliosis patients were selected from a multicenter image bank, representing various clinical scenarios (different age, gender, curve type, BMI, and pre- and postoperative images). The 12 observers measured the photographs at two different times with a three-week interval. For the second round, the images were randomly mixed. Inter- and intra-observer variabilities of the measurements were analyzed using intraclass correlation coefficients (ICCs), and reliability was measured by the standard error of measurement (SEM). Group comparisons were made using Student's t-test. Results: The mean inter-observer ICC for the ten measurements was 0.981, the mean intra-observer ICC was 0.937, and SEM was 0.3-1.3°. The parameter with the strongest inter- and intra-observer validity was the difference in waistline angles 0.994 and 0.974, respectively, while the highest variability was found with the waist height angle 0.963 and 0.845, respectively. No test-retest differences (p > 0.05) were observed between researchers (0.948 ± 0.04) and surgeons (0.925 ± 0.05). Conclusion: We developed a new digital tool integrated into an online platform demonstrating excellent reliability and inter- and intra-observer variabilities for quantifying body asymmetry in scoliosis patients from a simple clinical photograph. The method could be used for assessing and monitoring scoliosis and body asymmetry without radiation.

Automatic assessment of scoliosis surgery outcome on trunk shape using left-right trunk asymmetry

PURPOSE

To present a novel set of Left-Right Trunk Asymmetry (LRTA) indices and use them to assess the postoperative appearance of the trunk in Adolescent Idiopathic Scoliosis (AIS) patients.

METHODS

We hypothesize that LRTA measurements provide complementary information to existing trunk asymmetry indices when documenting the outcome of scoliosis surgery. Forty-nine AIS patients with thoracic curves who underwent posterior spinal fusion were included. All had surface topography scans taken preoperatively and at least 6 months postoperatively. We documented spinal curvature using Radiographic Cobb angles, scoliometer readings and coronal balance. To evaluate Global Trunk Asymmetry (GTA), we used the standard measures of Back Surface Rotation (BSR) and Trunk Lateral Shift (TLS). To measure LRTA, we identified asymmetry areas as regions of significant deviation between the left and right sides of the 3D back surface. New parameters called Deformation Rate (DR) and Maximum Asymmetry (MA) were measured in different regions based on the asymmetry areas. We compared the GTA and LRTA changes with those in spinal curvature before and after surgery.

RESULTS

The GTA indices, mainly TLS, showed improvement for more than 75% of patients. There was significant improvement of LRTA in the shoulder blades and waist regions (95% and 80% of patients respectively).

CONCLUSION

We report positive outcomes for LRTA in the majority of patients, specifically in the shoulder blades and waist, even when no reduction of BSR is observed. The proposed indices can evaluate local trunk asymmetries and the degree to which they are improved or worsened after scoliosis surgery.

3D Back Contour Metrics in Predicting Idiopathic Scoliosis Progression: Retrospective Cohort Analysis, Case Series Report and Proof of Concept

Adolescent Idiopathic Scoliosis is a 3D spinal deformity commonly characterized by serial radiographs. Patients with AIS may have increased average radiation exposure compared to unaffected patients and thus may be implicated with a modest increase in cancer risk. To minimize lifetime radiation exposure, alternative imaging modalities such as surface topography are being explored. Surface topography (ST) uses a camera to map anatomic landmarks of the spine and contours of the back to create software-generated spine models. ST has previously shown good correlation to radiographic measures. In this study, we sought to use ST in the creation of a risk stratification model. A total of 38 patients met the inclusion criteria for curve progression prediction. Scoliotic curves were classified as progressing, stabilized, or improving, and a predictive model was created using the proportional odds logistic modeling. The results showed that surface topography was able to moderately appraise scoliosis curvatures when compared to radiographs. The predictive model, using demographic and surface topography measurements, was able to account for 86.9% of the variability in the future Cobb angle. Additionally, attempts at classification of curve progression, stabilization, or improvement were accurately predicted 27/38 times, 71%. These results provide a basis for the creation of a clinical tool in the tracking and prediction of scoliosis progression in order to reduce the number of X-rays required.

Exploring Correlations Between Pain and Deformity in Idiopathic Scoliosis With Validated Self-reported Pain Scores, Radiographic Measurements, and Trunk Surface Topographic Measurements

BACKGROUND

Up to 75% of patients with idiopathic scoliosis (IS) report back pain, but the exact contributors are unclear. This study seeks to assess how pain correlates with demographics, radiographic and surface topographic (ST) measurements, and patient-reported outcome measures (PROMs) in patients with IS.

METHODS

Patient-Reported Outcome Measurement Information System (PROMIS) Pain Interference (PI) and Scoliosis Research Society revised (SRS-22r) pain domain from an IRB approved prospectively collected registry containing patients 11 to 21 years old with IS were correlated (Spearman coefficients) with measurements from whole-body EOS radiography and ST scanning, PROMIS 1.0 PROMs, Trunk Appearance Perception Scale (TAPS), and SRS-22r domains. SRS-22r and PROMIS-PI were also compared between different sex, scoliosis severities, and primary curve locations with Mann-Whitney U or Kruskal-Wallis tests, and if significant differences were found, included with the 5 highest univariate correlated variables into stepwise multivariate linear regression models ( P <0.05 to enter, P >0.1 to remove) predicting SRS-22r pain and PROMIS-PI.

RESULTS

One hundred and forty-nine patients (14.5 ± 2.0 y, body mass index 20.6 ± 4.1 kg/m 2 , 96 (64%) female, mean major coronal curve 40 ± 19 deg, range: 10 deg, 83 deg) reported mean PROMIS-PI of 42.2 ± 10.0 and SRS-22r pain of 4.4 ± 0.6. SRS-22r self-image was the most correlated variable with both SRS-22r pain (rho=0.519) and PROMIS-PI (rho=-0.594). Five variables, none of which were ST or radiographic measures, strongly predicted SRS pain domain (R=0.711, R2=0.505, N=138). Two variables (SRS-22r self-image and SRS-22r function) were utilized by a model correlated with PROMIS-PI (R=0.687, R2=0.463, N=124).

CONCLUSIONS

SRS-22r function and self-image domains were more strongly correlated with SRS-22r pain and PROMIS-PI than any radiographic or ST measurements.

LEVEL OF EVIDENCE

Level II-retrospective study.

Non-Invasive Assessment of Back Surface Topography: Technologies, Techniques and Clinical Utility

(1) Background: Frequent exposure to ionising radiation is often used to determine the diagnosis of adolescent idiopathic scoliosis (AIS), a lateral curvature of the spine in those aged between 10 and 18 years, and a treatment plan according to Cobb angle. This narrative review outlines the clinical utility of surface topography (ST), a radiation-free imaging modality. (2) Methods: Publicly available databases were searched to yield literature related to ST. Identified articles were classified based on the equipment used and in order of how it was developed, i.e., historical, recent developments, and state-of-the-art developments. (3) Conclusions: ST is a reliable cost-effective non-invasive technique that provides an alternative to radiation-based imaging to aid with the diagnosis and potential screening of AIS. Several scanning methods are available, which allows ST to be used in several clinical environments. Limitations of inter-reliability and differences of apparatus resulting in variations of data have been noted through this narrative review.

Analysis of the mechanism and clinical classification of thoracolumbar scoliosis using three-dimensional EOS and surface electromyography

To analyze a thoracolumbar scoliosis group, we analyzed data from the acquired database by groups: the sEMG group (n = 16) and 3D-EOS group (n = 55). The asymmetric hyper/hypoactivation ratio of muscle and LLD (>3 mm) were measured in the sEMG group. In the 3D-EOS group, we recorded the values of parameters including LLD, pelvis rotation, and kyphosis/lordosis. In the sEMG study, sEMG examinations were conducted individually in patients with idiopathic scoliosis to analyze hyper/hypoactivation of the paraspinal muscle. In the three-dimensional EOS study, the Cobb angle, femoral height difference, and thoracic kyphosis and lumbar lordosis angles were measured using 2D images and 3D reconstructed images. Sixteen patients with thoracolumbar scoliosis were classified into asymmetric hyperactivation (A-Hyper) and asymmetric hypoactivation (A-Hypo) groups. The Cobb angle of the A-Hyper subtype was significantly higher than that of the A-Hypo subtype (22.41 versus 15.2, p = 0.023). Coronal deviation (p = 0.028) and the pelvis rotation angle (p = 0.001) were significantly higher in the LLD (+) subtype than in the LLD (-) subtype. When we classified patients cross-sectionally along with A-Hyper/Hypo and LLD (±), A-Hyper elevated the Cobb angle, and LLD (+) was significantly correlated with coronal deviation and pelvis rotation. In the 3D-EOS evaluation, the pelvic height difference (p = 0.043) and coronal deviation (p = 0.001) were significantly higher in the LLD (+) subtype than in the LLD (-) subtype. In conclusions, paraspinal muscular asymmetry and LLD can be strong factors in inducing or progressing thoracolumbar scoliosis.

A new scoliosis brace padding method based on trunk asymmetry for scoliosis treatment

BACKGROUND

Pressure pads are used with scoliosis braces to adjust the magnitude and location of corrective forces that mechanically support the torso to correct the spine deformity. In the conventional brace (C.B.) design approaches, the location and shape of pads are determined based on the visual assessment of the clinician. The accuracy of this approach could be improved because it is limited to the clinician's expertise. The present study aimed to develop a new brace (N.B.) padding method based on trunk asymmetry for adolescents with idiopathic scoliosis and compare the efficacy of the developed method with C.B. in improving the Cobb angle and body posture symmetricity.

METHODS

The trunk surface geometry was scanned using a 3-dimensional scanner. The best plane of symmetry was determined, and the original trunk was reflected in the plane of symmetry, creating the reflected trunk. The difference between the reflected and original trunks was computed and color-coded using deviation contour maps. The boundary of deformed regions, with a minimum of 6-mm deviation contour maps, was identified as the trim lines for brace pads. Eight participants were recruited and divided into conventional and new padding groups. The variation of Cobb angle and torso asymmetry parameters, including the trunk rotation and back surface rotation, as well as the brace satisfaction and trunk appearance perception of the 2 groups, were compared after 3 months of treatment.

RESULTS

Cobb angle improved equally in the N.B. and C.B. groups. However, back surface rotation improved in the N.B. group (+49.6%) and worsened in the C.B. group (-6.8%). The mean trunk rotation was improved by 30% in the N.B. and further exacerbated by -2.2% in the C.B. group. The brace satisfaction and trunk appearance perception scores were higher in the N.B. than in the C.B. group, however not statistically significant.

CONCLUSIONS

The present study showed that the proposed brace padding system improved the trunk appearance without negatively affecting the Cobb angle correction.

Classification of spinal curvature types using radiography images: deep learning versus classical methods

Scoliosis is a spinal abnormality that has two types of curves (C-shaped or S-shaped). The vertebrae of the spine reach an equilibrium at different times, which makes it challenging to detect the type of curves. In addition, it may be challenging to detect curvatures due to observer bias and image quality. This paper aims to evaluate spinal deformity by automatically classifying the type of spine curvature. Automatic spinal curvature classification is performed using SVM and KNN algorithms, and pre-trained Xception and MobileNetV2 networks with SVM as the final activation function to avoid vanishing gradient. Different feature extraction methods should be used to investigate the SVM and KNN machine learning methods in detecting the curvature type. Features are extracted through the representation of radiographic images. These representations are of two groups: (i) Low-level image representation techniques such as texture features and (ii) local patch-based representations such as Bag of Words (BoW). Such features are utilized by various algorithms for classification by SVM and KNN. The feature extraction process is automated in pre-trained deep networks. In this study, 1000 anterior-posterior (AP) radiographic images of the spine were collected as a private dataset from Shafa Hospital, Tehran, Iran. The transfer learning was used due to the relatively small private dataset of anterior-posterior radiology images of the spine. Based on the results of these experiments, pre-trained deep networks were found to be approximately 10% more accurate than classical methods in classifying whether the spinal curvature is C-shaped or S-shaped. As a result of automatic feature extraction, it has been found that the pre-trained Xception and mobilenetV2 networks with SVM as the final activation function for controlling the vanishing gradient perform better than the classical machine learning methods of classification of spinal curvature types.

Development and validation of a semi-automated measurement tool for calculating consistent and reliable surface metrics describing cosmesis in Adolescent Idiopathic Scoliosis

Adolescent Idiopathic Scoliosis (AIS) is a 3D spine deformity that also causes ribcage and torso distortion. While clinical metrics are important for monitoring disorder progression, patients are often most concerned about their cosmesis. The aim of this study was to automate the quantification of AIS cosmesis metrics, which can be measured reliably from patient-specific 3D surface scans (3DSS). An existing database of 3DSS for pre-operative AIS patients treated at the Queensland Children's Hospital was used to create 30 calibrated 3D virtual models. A modular generative design algorithm was developed on the Rhino-Grasshopper software to measure five key AIS cosmesis metrics from these models-shoulder, scapula and hip asymmetry, torso rotation and head-pelvis shift. Repeat cosmetic measurements were calculated from user-selected input on the Grasshopper graphical interface. InterClass-correlation (ICC) was used to determine intra- and inter-user reliability. Torso rotation and head-pelvis shift measurements showed excellent reliability (> 0.9), shoulder asymmetry measurements showed good to excellent reliability (> 0.7) and scapula and hip asymmetry measurements showed good to moderate reliability (> 0.5). The ICC results indicated that experience with AIS was not required to reliably measure shoulder asymmetry, torso rotation and head-pelvis shift, but was necessary for the other metrics. This new semi-automated workflow reliably characterises external torso deformity, reduces the dependence on manual anatomical landmarking, and does not require bulky/expensive equipment.

A survey of the clinical practice followed by Korean medicine doctors for scoliosis: Preliminary data for clinical practice guidelines

Scoliosis is a spinal disease in which the Cobb angle is >10°. Scoliosis treatment can be surgical or conservative, and clinical practice guidelines (CPGs) for conservative treatments have been updated since 2006. There have been several articles regarding the efficacy and safety of Korean medicine (KM) in treating scoliosis, but there are no CPGs. Our study investigated the current clinical practice using a survey for the future establishment of KM-CPGs. The survey mainly comprised clinical practice status, diagnosis, treatment, progress and prognosis, and perception of KM on scoliosis, with reference to existing surveys of other musculoskeletal disorders and scoliosis-related articles. A web-based survey was conducted from February 16, 2021 to February 28, 2021. We found that 60% of KM doctors (KMDs) respondents treated patients with scoliosis, and they valued radiographical measurements and scoliosis-related factors in the diagnosis. KMDs used multiple KM treatments, including acupuncture, Chuna, cupping, pharmacopuncture, and herbal medicine, and they emphasized the importance of KM more in nonstructural scoliosis than in structural scoliosis. Although the perception of the prognosis of scoliosis was in agreement with that suggested by previous guidelines, KMDs showed outstanding focus on reduction of symptoms of scoliosis and improvement of quality of life. Despite some limitations, including low participation and the need for consulting other medical practitioners, our study may be helpful for the development of KM-CPGs because it is the first to analyze the perceptions of KMDs on scoliosis and to collect preliminary data that are of significance for preparing clinical guidelines.

Obtaining patient torso geometry for the design of scoliosis braces. A study of the accuracy and repeatability of handheld 3D scanners

OBJECTIVE

Obtaining patient geometry is crucial in scoliosis brace design for patients with adolescent idiopathic scoliosis. Advances in 3D scanning technologies provide the opportunity to obtain patient geometries quickly with fewer resources during the design process compared with the plaster-cast method. This study assesses the accuracy and repeatability of such technologies for this application.

METHODS

The accuracy and repeatability of three different handheld scanners and phone-photogrammetry was assessed using different mesh generation software. Twenty-four scans of a single subject's torso were analyzed for accuracy and repeatability based on anatomical landmark distances and surface deviation maps.

RESULTS

Mark II and Structure ST01 scanners showed maximum mean surface deviations of 1.74 ± 3.63 mm and 1.64 ± 3.06 mm, respectively. Deviations were lower for the Peel 1 scanner (maximum of -0.35 ± 2.8 mm) but higher with the use of phone-photogrammetry (maximum of -5.1 ± 4.8 mm). The mean absolute errors of anatomical landmark distance measurements from torso meshes obtained with the Peel 1, Mark II, and ST01 scanners were all within 9.3 mm (3.6%), whereas phone-photogrammetry errors were as high as 18 mm (7%).

CONCLUSIONS

Low-cost Mark II and ST01 scanners are recommended for obtaining torso geometries because of their accuracy and repeatability. Subject's breathing/movement affects the resultant geometry around the abdominal and anterolateral regions.

A Survey of Methods and Technologies Used for Diagnosis of Scoliosis

The purpose of this article is to present diagnostic methods used in the diagnosis of scoliosis in the form of a brief review. This article aims to point out the advantages of select methods. This article focuses on general issues without elaborating on problems strictly related to physiotherapy and treatment methods, which may be the subject of further discussions. By outlining and categorizing each method, we summarize relevant publications that may not only help introduce other researchers to the field but also be a valuable source for studying existing methods, developing new ones or choosing evaluation strategies.

Assessment of the reliability of hand-held surface scanner in the evaluation of adolescent idiopathic scoliosis

PURPOSE

Spinal deformities due to adolescent idiopathic scoliosis (AIS) result in impairment in the back surface topography. Sophisticated interventions are needed that address different aspects of deformity. The purpose of our study is to test the reliability of hand-held 3D scanners on the assessment of AIS.

METHODS

Forty-two AIS patients were included in our study. The back surfaces of the patients were scanned with the hand-held 3D scanner, while the patients were in the standing position with the arms hanging at the sides (P1), with the arms extended (P2), and forward bending position (P3). The acquired original image was superimposed with the mirror image. Root mean square (RMS) of the point-to-point distance was calculated, and the differences between the surfaces were determined. Correlation between RMS, Cobb, POTSI, scoliometer, radiographic rotations, TRACE results was calculated.

RESULTS

A significant correlation coefficency (r) was found between the RMS and Cobb values in the thoracic (P1 = 0.80, P2 = 0.76, P3 = 0.71) and lumbal region (P1 = 0.56, P2 = 0.65, P3 = 0.63); between RMS and Raimondi in the thoracic (r, P1 = 0.80, P2 = 0.81, P3 = 0.78) and lumbar regions (P1 = 0.54, P2 = 0.64, P3 = 0.59); between RMS and scoliometer measurements in the thoracic (r, P1 = 0.58, P2 = 0.50, P3 = 0.41) and lumbar regions (P1 = 0.35, P2 = 0.41, P3 = 0.59); in thoracolumbar region between RMS and POTSI (P1 = 0.50, P2 = 0.25, P3= 0.36), between RMS and TRACE (P1 = 0.68, P2 = 0.5, P3 = 0.52), CONCLUSION: The hand-held scanners may contribute to gaining new insight into diagnosis and follow-up of AIS by its mobility that enables the acquisition of data in desired body position and place such as bedside or our patient clinics.

LEVEL OF EVIDENCE IV

Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

Evaluation of facial symmetry after jaw reconstruction surgery

The current study proposes a 3D objective method of evaluating facial symmetry after reconstructive surgery of orofacial structures. 3D models of the craniofacial and soft tissue surfaces were reflected about the mid-sagittal plane. The original model was aligned with the reflection and the best plane of symmetry was found. A deviation contour map quantified the areas of asymmetry and gave a global score of the asymmetry. The asymmetry scores were successfully obtained for 18 patients who had underwent reconstruction of lower face. The asymmetry values at craniofacial and soft tissue levels were moderately correlated (R2=0.39). Overall, the developed method effectively highlights areas of asymmetry and can help evaluate aesthetic outcomes of facial reconstruction surgery.

Clinical classification of scoliosis patients using machine learning and markerless 3D surface trunk data

Markerless 3D surface topography for scoliosis diagnosis and brace treatment can avoid repeated radiation known from standard X-ray analysis and possible side effects. Combined with the method of torso asymmetry analysis, curve severity and progression can be evaluated with high reliability. In the current study, a machine learning approach was utilised to classify scoliosis patients based on their trunk surface asymmetry pattern. Frontal X-ray and 3D scanning analysis with a clinical classification based on Cobb angle and spinal curve pattern were performed with 50 patients. Similar as in a previous study, each patient's trunk 3D reconstruction was used for an elastic registration of a reference surface mesh with fixed number of vertices. Subsequently, an asymmetry distance map between original and reflected torso was calculated. A fully connected neural network was then utilised to classify patients regarding their Cobb angle (mild, moderate, severe) and an Augmented Lehnert-Schroth (ALS) classification based on their full torso asymmetry distance map. The results reveal a classification success rate of 90% (SE: 80%, SP: 100%) regarding the curve severity (mild vs moderate-severe) and 50-72% regarding the ALS group. Identifying patient curve severity and treatment group was reasonably possible allowing for a decision support during diagnosis and treatment planning. Graphical abstract.

Analysis of four methods of measuring three-dimensional pelvic tilt in the lateral decubitus position

Proper alignment of acetabular implantation is necessary for good patient outcomes and preventing complications or additional surgeries in total hip arthroplasty (THA). Rotation of the pelvis in lateral decubitus (LD) is typically not accounted for as surgeons use the surgery table as a reference plane to align implants. This study compared four techniques to measure 3D pelvic rotations in LD position using computer models. CT scans of 19 subjects in LD position were used to create 3D pelvis models. Pelvic rotations were measured by three users using four techniques: landmark (LM), defined plane (DP), anterior pelvic plane (APP), and plane of best symmetry (POBS) methods. Measurements were analysed for intra-user reliability and relationships between methods were assessed using intraclass correlation coefficient, standard error of measurement, and coefficient of determination. The POBS method exhibited the highest inter-observer reliability and is recommended as a new measurement technique to measure pelvic rotations before THA surgery. The LM method exhibited low reliability but may be suitable for expert users familiar with pelvic landmarks. The APP method should only be used when the patients' APP planes are known in neutral standing and side-lying postures. The DP method is not recommended due to substantial individual variability. Graphical abstract.

Innovative decision support for scoliosis brace therapy based on statistical modelling of markerless 3D trunk surface data

Recently markerless 3D scanning methods receive an increased interest for therapy planning and brace treatment of patients with scoliosis. This avoids repeated radiation known from standard X-Ray analysis. Several authors introduced the method of asymmetry distance maps in order to classify curve severity and progression. The current work extends this approach by statistical mean shape 3D models of the human trunk in order to classify patients. 50 patients were included in this study performing frontal X-ray and 3D scanning analysis. All patients were classified by a clinician according to their Cobb angle and spinal curve pattern (Augmented-Lehnert-Schroth ALS). 3D reconstructions of each patient trunk were processed in a way to elastically register a reference surface mesh with fixed number of data points. Mean 3D shape models were generated for each curve pattern. An asymmetry distance map was then calculated for each patient and mean shape model. Single patient 3D reconstructions were classified according to severity and ALS treatment group. Optimal sensitivity and specificity was 97%/39% thoracic and 87%/42% lumbar respectively for detecting mild and moderate-severe patients. Identifying a treatment group was possible for three combined groups allowing to support decisions during diagnosis and therapy planning.

Understanding breast asymmetry and its relation to AIS

STUDY DESIGN

Literature Review.

OBJECTIVE

Review the pathophysiology, causes, and treatment of breast asymmetry in patients with adolescent idiopathic scoliosis (AIS), as well as postoperative patient assessment and health-related quality of life.

BACKGROUND DATA

Female breast development begins at 35-day gestation and continues 2-4-year post-thelarche to achieve final volume and shape. During the post-pubertal period, errors in growth and development may result in breast asymmetry. Breast asymmetry typically attenuates with time, but can be pronounced in individuals with AIS. During adolescence, there is rapid development and, thus AIS patients are increasingly sensitive, physically and emotionally, to breast changes. While breast asymmetry can be monitored through radiographic measures and surface topography, pre- and postoperative patient assessment is also critical in determination of optimal patient treatment.

METHODS

A comprehensive literature review was performed on the pathophysiology, causes, and treatment of breast asymmetry. The advantages and limitations of various treatment options based on patient satisfaction were also investigated.

RESULTS

Various treatment options exist for breast asymmetry correction in AIS patients. Surgical correction involves an aesthetic outcome, as well as social, physical, and psychological impact on the patient. Despite the benefit of correction surgery, in terms of function and self-image, patient-reported outcomes still appear lower postoperatively in the domains of pain and mental health.

CONCLUSION

Breast asymmetry is very common, especially among AIS patients, and is often corrected with surgical augmentation. AIS correction surgery has been shown to aggravate breast asymmetry and negatively affect patient-reported outcomes. Other treatment modalities should thus be considered when presented with an adolescent patient. Understanding patient concerns and their relation to quality of life will help guide surgical and medical interventions in correction of AIS deformities. Long-term follow-up studies are necessary to determine whether such interventions are successful and if patients remain healthy.

LEVEL OF EVIDENCE

N/A.

Construct validity of the Trunk Aesthetic Clinical Evaluation (TRACE) in young people with idiopathic scoliosis

BACKGROUND

Aesthetics is recognized as a main outcome in idiopathic scoliosis (IS) treatment, but to date, there is no criterion standard for physicians' evaluation. Trunk Aesthetic Clinical Evaluation (TRACE) is a simple 12-point ordinal scale to quantify symmetry as a proxy of aesthetics. TRACE is already diffused worldwide and has been used in clinical research.

OBJECTIVE

We aimed to validate TRACE and improve it with Rasch analysis.

MATERIAL AND METHODS

This study involved an observational Rasch analysis validation of an evaluation tool in outpatient rehabilitation centres. From a clinical database, we randomly selected patients who had IS, were age 10 to 18, had brace prescription at first evaluation, and had at least 2 consultations. Rasch analysis (partial credit model) was used. Differential item functioning (DIF) was assessed for age, sex, disease severity, bracing and treatment. The median was chosen to dichotomize disease severity and bracing. We removed 64 outlier participants (4%).

RESULTS

We included 1553 participants (1334 females; mean [SD] age 13 [1.7] years old). TRACE items showed ordered thresholds and proper fit to the Rasch model. The score-to-measure conversion table showed proper length (range -4.55 to 4.79 logit) with a mean (SE) measure of -0.52 (0.04) logit. The principal component analysis supported the TRACE unidimensionality. The TRACE was free from DIF for age, sex and bracing.

CONCLUSIONS

The TRACE ordinal scale has been converted into a Rasch-consistent, interval-level measure of trunk aesthetics in IS patients and can be used to compare different populations. Its main flaw is low reliability, likely because of the small number of items. TRACE can be used as an outcome measure and in everyday clinical evaluation of IS, even if new developments of the scale are advised.

Investigation of pelvic symmetry using CAD software

Severe pelvic fractures often prove difficult for surgeons as they require patient-specific surgical treatment plans and customized equipment. Developing virtual patient-specific 3D pelvis models would ease the surgical planning process and enable development of custom fixation plates. This paper aims to examine pelvic symmetry to conclude whether the contralateral side may be used as a reference model for the fractured side of the pelvis. Fourteen subjects with intact pelvises were involved in this study. CT scans of the pelvises were converted to 3D models and the right sides of the pelvises were reflected and aligned with the left sides. A deviation analysis was then performed for each set of models and results showed that the average root mean square (RMS) of values was 1.14 ± 0.26 mm and the average percentage of points below a deviation threshold of ± 2 mm was 91.9 ± 5.55%. The deviation color maps (DCMs) showed that the largest deviations were on the non-articular surfaces. The volume and surface area of each model were also examined and showed no significant differences between left and right sides. These results indicate that the pelvis displays bilateral symmetry and this concept can be used to develop fully intact patient-specific 3D pelvis models for fracture reconstruction using the unfractured contralateral side. Graphical Abstract.

Three-dimensional depth sensor imaging to identify adolescent idiopathic scoliosis: a prospective multicenter cohort study

Adolescent idiopathic scoliosis is the most ordinary pediatric spinal disease that causes a three-dimensional deformity. Early detection of this potentially progressive deformity is considered crucial. The purpose of the present study was to report the potential for accurately diagnosis of adolescent idiopathic scoliosis using a newly developed, automated, noninvasive asymmetry-recognition system for the surface of the human back using a three-dimensional depth sensor. We included 170 subjects with suspected adolescent idiopathic scoliosis in this study. Outcomes measured included patient demographics, Cobbe angles from radiographic measurements, and asymmetry indexes. The coefficient of correlation between the asymmetry index and the Cobb angle was 0.85. For the prediction of scoliosis >10°, the area under the curve was 0.98, sensitivity was 0.97, specificity was 0.93, positive predictive value was 0.99, negative predictive value was 0.72, accuracy was 0.97, positive likelihood ratio was 13.55, and negative likelihood ratio was 0.04. The posterior test probability for the positive screen >10° was 98.9% if the asymmetry index was >1.268, three times in a row. This novel system automatically evaluated the back asymmetry. Therefore, this study demonstrates the outstanding discriminative ability of this newly developed system for deciding whether an examinee should undergo additional radiography to define scoliosis. This system can be used as an alternative to the forward bend test and scoliometer measurement in clinics. Future studies should seek to confirm these findings in a larger group and involve mass school scoliosis screening programs within the context of a multicenter trial.

Anatomical reference marks, evaluation parameters and reproducibility of surface topography for evaluating the adolescent idiopathic scoliosis: a systematic review with meta-analysis

BACKGROUND

Surface topography is a radiation-free examination that provides relevant information for the evaluation of patients with Adolescent Idiopathic Scoliosis (AIS). However, its usage is not standardized, which restricts the applicability of this instrument.

RESEARCH QUESTIONS

(a) To identify the anatomical reference markers used on surface topography; (b) to identify the parameters used on surface topography; and (c) to pool correlation and reproducibility results.

METHODS

Systematic searches were conducted following MOOSE (Meta-analysis of Observational Studies in Epidemiology) guidelines. The methodological quality was assessed according to Brink & Louw appraisal tool.

RESULTS

Twenty-three studies were included for the qualitative synthesis. The most commonly used anatomical reference markers were: the prominent vertebra (C7 or T1), the posterior superior iliac spines (PSISs) and the sacrum (S1). The parameters for the evaluation of the AIS by surface topography are: spinal inclination angle (analogous to Cobb), gibbosity, thoracic kyphosis angle, lumbar lordosis angle, pelvic obliquity, spine length, apex of the curve, C7-S1 distance (frontal plane), and C7-S1 displacement (sagittal plane). Data from eleven studies were metanalyzed and evidenced the correlation of the surface topography with X-ray exams and the reproducibility of the surface topography in the sagittal and frontal planes.

SIGNIFICANCE

The findings of this study recommend the use of a protocol for the application of the equipment. The analyzed studies predict the use of only four markers for anatomical reference. The evaluation of the AIS can be carried out observing nine parameters. Surface topography correlates with radiography when the spinal inclination angle (Cobb angle), thoracic kyphosis angle and lumbar lordosis angle are compared. Also, surface topography presents inter and intra-rater reproducibility in the sagittal plane and intra-rater reproducibility in the frontal plane.

Non-ionizing method of screening adolescent idiopathic scoliosis in schoolchildren

Adolescent idiopathic scoliosis (AIS) affects 2% to 4% of young people in Brazil. Repeated exposures to radiation used in the monitoring of the deformity can be harmful to the health. This study aimed to present a photogrammetry protocol as a non-ionizing method to quantify scoliosis and relate it to the Cobb radiological method. Sixteen individuals with idiopathic scoliosis (age: 21.4 ± 6.1 years, body mass index: 19.8 ± 0.2 kg/m2) underwent standing posteroanterior X-ray examination of the trunk. Additionally, markers were placed on the spinal processes of the C7 to L5 vertebrae, and posterior trunk photographs were taken. All images were sent for independent analysis by two examiners who were trained in the quantification of scoliosis. The average of the thoracic curvature evaluated through the photogrammetry and Cobb methods were 36.43° and 36.14°, respectively. With an average difference of 4.1°, the methods were not statistically different (p < 0.05). As a non-ionizing method that is low cost and portable, photogrammetry may represent a suitable alternative to the radiological method. Further studies are needed for the improvement of non-ionizing techniques in AIS screening.

Automated noninvasive detection of idiopathic scoliosis in children and adolescents: A principle validation study

Idiopathic scoliosis is the most common pediatric musculoskeletal disorder that causes a three-dimensional deformity of the spine. Early detection of this progressive aliment is essential. The aim of this study is to determine outcomes using a newly developed automated asymmetry-evaluation system for the surface of the human back using a three-dimensional depth sensor. Seventy-six human subjects suspected to have idiopathic scoliosis were included in this study. Outcome measures include patient demographics, radiographic measurements, and asymmetry indexes defined in the automated asymmetry-recognition system. The mean time from scanning to analysis was 1.5 seconds. For predicting idiopathic scoliosis of greater than 25°, the area under the curve was 0.96, sensitivity was 0.97, and specificity was 0.88. The coefficient of variation for repeatability analyses using phantom models was 1–4%. The intraclass correlation coefficient obtained for intra-observer repeatability for human subjects was 0.995. The system three-dimensionally scans multiple points on the back, enabling an automated evaluation of the back’s asymmetry in a few seconds. This study demonstrated discriminative ability in determining whether an examinee requires an additional x-ray to confirm diagnosis.

Accuracy of 3D surface scanners for clinical torso and spinal deformity assessment

Externally visible deformities are cosmetic features of great concern for Adolescent Idiopathic Scoliosis (AIS) patients. Current assessment techniques for AIS do not fully encompass the external deformity. A non-invasive method capable of capturing superficial anatomy, such as 3D scanning, would enable better qualitative and quantitative evaluation of cosmesis. This study aimed to quantify the accuracy of commonly available scanners, in assessing posterior asymmetry in AIS. The technique of 3D surface deviation analysis was proposed as a suitable method for comparing the models created by each scanner. Eight plaster cast moulds manufactured to create braces for AIS patients were used as test samples. Four 3D scanners were selected: Solutionix RexScan CS+; Artec Eva; Microsoft Kinect V1; iPhone with 123D Catch App. These scanners were selected from those available as representative of a range of scanning technologies. Each cast was scanned and 3D models created. A simulated rib hump measurement was obtained and the surface-to-surface deviations between the Solutionix scan and all other scans were determined. The Solutionix scanner is a metrology scanner of very high quality and so it was selected as the reference. Surface-to-surface deviations were calculated in the positive and negative directions separately to specifically identify size and volume inaccuracies created by the scans. Surface deviations showed excellent agreement between the Solutionix and the Eva with deviations of +0.17 ± 0.17 mm (Eva regions larger) and -0.20 ± 0.32 mm (Eva regions smaller) (mean±SD). The Kinect showed lower agreement (+1.58 ± 1.50 mm and -0.58 ± 0.58 mm). The iPhone scans were not able to be scaled to the correct size, so were excluded. Rib hump measurements with all scanners were within clinical measurement variability (±4.9 deg) of the known values. These commercially available 3D scanners are capable of imaging torso shape in 3D and deriving clinically relevant external deformity measures. The non-invasive 3D topographic information provided can be used to improve assessment of torso shape in spinal deformity patients.

Automatic extraction of the 3D symmetry line of back surface: application on scoliotic adolescents

We propose a new method to extract automatically the symmetry line of the 3D back surface of patients affected by scoliosis. Our method is based on the detection of local symmetry planes computed on thick layers of the back. Results have been obtained on a sample of 112 scoliotic adolescents and we compare the symmetry line obtained by our method with a reference line defined by clinicians. We also study the influence of the scoliosis severity and of the Body Mass Index on the results.

3D Markerless asymmetry analysis in the management of adolescent idiopathic scoliosis

BACKGROUND

Three dimensional (3D) markerless asymmetry analysis was developed to assess and monitor the scoliotic curve. While the developed surface topography (ST) indices demonstrated a strong correlation with the Cobb angle and its change over time, it was reported that the method requires an expert for monitoring the procedure to prevent misclassification for some patients. Therefore, this study aimed at improving the user-independence level of the previously developed 3D markerless asymmetry analysis implementing a new asymmetry threshold without compromising its accuracy in identifying the progressive scoliotic curves.

METHODS

A retrospective study was conducted on 128 patients with Adolescent Idiopathic Scoliosis (AIS), with baseline and follow-up radiograph and surface topography assessments. The suggested "cut point" which was used to separate the deformed surfaces of the torso from the undeformed regions, automatically generated deviation patches corresponding to scoliotic curves for all analyzed surface topography scans.

RESULTS

By changing the "cut point" in the asymmetry analysis for monitoring scoliotic curves progression, the sensitivity for identifying curve progression was increased from 68 to 75%, while the specificity was decreased from 74 to 59%, compared with the original method with different "cut point".

CONCLUSIONS

These results lead to a more conservative approach in monitoring of scoliotic curves in clinical applications; smaller number of radiographs would be saved, however the risk of having non-measured curves with progression would be decreased.

2016 SOSORT guidelines: orthopaedic and rehabilitation treatment of idiopathic scoliosis during growth

BACKGROUND

The International Scientific Society on Scoliosis Orthopaedic and Rehabilitation Treatment (SOSORT) produced its first guidelines in 2005 and renewed them in 2011. Recently published high-quality clinical trials on the effect of conservative treatment approaches (braces and exercises) for idiopathic scoliosis prompted us to update the last guidelines' version. The objective was to align the guidelines with the new scientific evidence to assure faster knowledge transfer into clinical practice of conservative treatment for idiopathic scoliosis (CTIS).

METHODS

Physicians, researchers and allied health practitioners working in the area of CTIS were involved in the development of the 2016 guidelines. Multiple literature reviews reviewing the evidence on CTIS (assessment, bracing, physiotherapy, physiotherapeutic scoliosis-specific exercises (PSSE) and other CTIS) were conducted. Documents, recommendations and practical approach flow charts were developed using a Delphi procedure. The process was completed with the Consensus Session held during the first combined SOSORT/IRSSD Meeting held in Banff, Canada, in May 2016.

RESULTS

The contents of the new 2016 guidelines include the following: background on idiopathic scoliosis, description of CTIS approaches for various populations with flow-charts for clinical practice, as well as literature reviews and recommendations on assessment, bracing, PSSE and other CTIS. The present guidelines include a total of 68 recommendations divided into following topics: bracing (n = 25), PSSE to prevent scoliosis progression during growth (n = 12), PSSE during brace treatment and surgical therapy (n = 6), other conservative treatments (n = 2), respiratory function and exercises (n = 3), general sport activities (n = 6); and assessment (n = 14). According to the agreed strength and level of evidence rating scale, there were 2 recommendations on bracing and 1 recommendation on PSSE that reached level of recommendation "I" and level of evidence "II". Three recommendations reached strength of recommendation A based on the level of evidence I (2 for bracing and one for assessment); 39 recommendations reached strength of recommendation B (20 for bracing, 13 for PSSE, and 6 for assessment).The number of paper for each level of evidence for each treatment is shown in Table 8.

CONCLUSION

The 2016 SOSORT guidelines were developed based on the current evidence on CTIS. Over the last 5 years, high-quality evidence has started to emerge, particularly in the areas of efficacy of bracing (one large multicentre trial) and PSSE (three single-centre randomized controlled trials). Several grade A recommendations were presented. Despite the growing high-quality evidence, the heterogeneity of the study protocols limits generalizability of the recommendations. There is a need for standardization of research methods of conservative treatment effectiveness, as recognized by SOSORT and the Scoliosis Research Society (SRS) non-operative management Committee.

Assessment of Vert-3D repeatability and reproducibility for evaluating the scoliosis of children with different nutritional profiles

Abstract Introduction: The Vert-3D is a radiation-free system which offers a three-dimensional view of the back’s surface, providing a quantitative assessment of spinal curvatures. Objective: To verify the repeatability, inter-rater reproducibility, and correlation between Cobb angles and the results of the Vert-3D system version 1 in the evaluation of the front curvatures of the spine in children with different nutritional profiles. Methods: The sample was composed of 115 children who underwent posterior-anterior panoramic digital radiography of the spine and five evaluations with the Vert-3D system by three trained raters. Results: Version 1 of the Vert-3D system showed: (1) significant and moderate correlations of repeatability for arrows on the left (ICC between .54 to .83) and significant and moderate correlations for arrows on the right (ICC between .55 to .60) for only normal BMI; (2) significant correlations of inter-rater reproducibility for left arrows (ICC between .47 to .65), weak to moderate correlations for right arrows (ICC between .29 to .60), and no significance for obese samples; and (3) significant correlations ranging between .31 and .60 on the left side and non-significant correlations to the right side between Cobb angles and scoliosis arrows. Conclusion: High correlation levels solely on the left side decrease the possibility of system-use for the assessment of scoliosis.

Surface Topography Classification Trees for Assessing Severity and Monitoring Progression in Adolescent Idiopathic Scoliosis

STUDY DESIGN

A validation study.

OBJECTIVE

The aim of this study was to independently validate the diagnostic accuracy of surface topography (ST) classification trees to identify curve severity and progression using a new sample of data in participants with adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Radiographs for diagnosing and monitoring AIS involve harmful radiation exposure repeated at successive clinical visits. Classification trees using a novel ST technique have been proposed to determine curve severity and progression noninvasively that could be used to monitor scoliosis.

METHODS

Forty-five adolescents with AIS treated nonoperatively, with ST scans and radiographs at baseline and follow-up (1 year later), were recruited from a scoliosis clinic. The Cobb angle (CA) from radiographs determined curve severity as mild (10° < CA < 25°) or moderate/severe (CA ≥ 25°) and progression as an increase >5°.ST scans were analyzed to calculate the best plane of symmetry and associated deviation color map. Root mean squares and maximum deviation were calculated for each area of asymmetry. ST measurements were analyzed using two published decision trees developed to maximize sensitivity and negative predictive value. Curves were classified as mild or moderate/severe and curve progression was predicted. Accuracy statistics were calculated to evaluate performance.

RESULTS

For curve severity, sensitivity and specificity were 95% and 35%, respectively. Negative and positive predictive values were 90% and 53%, respectively, with an accuracy of 61%. For curve progression, sensitivity and specificity were 73% and 44%, respectively. Negative and positive predictive values were 83% and 30%, respectively, with an accuracy of 51%. Assuming that mild and nonprogressive curves would not require an x-ray, the use of ST decision trees could eliminate 31% of x-rays.

CONCLUSION

Decision trees showed strong negative predictive values and sensitivity suggesting it may be possible to safely use ST asymmetry analysis with validated decision trees to reduce x-rays in patients with mild and nonprogressive curves.

LEVEL OF EVIDENCE

2.

Correlation Between a Novel Surface Topography Asymmetry Analysis and Radiographic Data in Scoliosis

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

To investigate the correlation between parameters extracted from a three-dimensional (3D) asymmetry analysis of the torso and the internal deformities of the spine presented on radiographs, including 1) curve number, direction and location; 2) location of the apical vertebra; and 3) curve severity.

SUMMARY OF BACKGROUND DATA

Surface topography (ST) is used to assess external torso deformities and may predict important characteristics of the underlying spinal curves. ST does not expose patients to radiation and could safely be used clinically for scoliosis patients. Most ST indices rely on anatomical landmarks on the torso and 2D measurements.

METHODS

The ability of a 3D markerless asymmetry technique to predict radiographic characteristics was assessed for 100 scoliosis patients with full torso ST scans. Twenty-four additional patients were used for validation. The number, direction, and location of curves were determined by three examiners using ST deviation color maps. The inter-method percentage of agreement and Kappa coefficient were estimated for each measure. Linear regression predicted the vertical location of the apical vertebra from ST. Curve severity (mild, moderate, severe) was predicted with a decision tree analysis using ST parameters.

RESULTS

The average percentage of agreement was 62%, 66%, and 23% for single, double, and triple curves, respectively. Curve direction was always correctly identified. The average percentages of agreement for curve location were 63%, 92%, and 62% for proximal thoracic, thoracic/thoracolumbar (T-TL), and lumbar (L) curves, respectively. Apical vertebra location was predicted with R² = 0.89 for T-TL and R² = 0.58 for L curves. ST parameters classified curve severity for T-TL and L curves with 73% and 59% accuracy, respectively.

CONCLUSIONS

The method presented here improves upon current ST techniques by using the entire torso surface and both a visual and quantitative representation of the asymmetry to better capture the torso deformity.

Reliability and validity of inexpensive and easily administered anthropometric clinical evaluation methods of postural asymmetry measurement in adolescent idiopathic scoliosis: a systematic review

PURPOSE

As accurate and reproducible measurements of spinal curvature are crucial in the examination of patients with adolescent idiopathic scoliosis (AIS), this systematic review aims to report on the reliability and validity of a range of inexpensive and easily administered anthropometric methods of postural asymmetry measurement in an AIS population, to inform practice in a clinical setting.

METHODS

A systematic search of health research databases located studies assessing reliability and validity of inexpensive and easily administered anthropometric measures.

RESULTS

Fourteen studies satisfied eligibility criteria. The methodological quality of included studies ranged from low to high. Validity studies were of moderate to high quality. In total, nine clinically applicable, inexpensive and easily administered anthropometric methods were identified, for assessing AIS curvature. All methods demonstrated high to very high inter-observer and intra-observer reliability. Reported criterion validity of the scoliometer and 2D photographs, when compared to Cobb angle assessed from radiographs, ranged from low to very high. iPhone measurements correlated well with scoliometer measurements. 2D photography results had a moderate to high correlation with 3D topography results.

CONCLUSIONS

Overall, strong levels of evidence exist for iPhone and scoliometer measurements, with a high to very high reliability and moderate to very high validity. Moderate levels of evidence exist for scoliometer with mathematical formula and clinical examination with moderate and low validity, respectively. Limited evidence exists for aesthetic tools TRACE and AI and 2D photography. These results indicate there are accurate and reproducible anthropometric measures that are inexpensive and applicable in therapy settings to assess postural asymmetry; however, these only exist for measurement in the transverse plane, despite 3D characteristics of AIS. Further research is required into an inexpensive and easily administered method that can assess postural asymmetry in all anatomical planes.

Monitoring for idiopathic scoliosis curve progression using surface topography asymmetry analysis of the torso in adolescents

BACKGROUND CONTEXT

At first visit and each clinical follow-up session, patients with adolescent idiopathic scoliosis (AIS) undergo radiographic examination, from which the Cobb angle is measured. The cumulative exposure to X-ray radiation justifies efforts in developing noninvasive methods for scoliosis monitoring.

PURPOSE

To determine the capability of the three-dimensional markerless surface topography (ST) asymmetry analysis to detect ≥5° progression in the spinal curvature in patients with AIS over 1-year follow-up interval.

STUDY DESIGN/SETTING

Cross-sectional study in a specialized scoliosis clinic.

PATIENT SAMPLE

In this study, baseline and 1-year follow-up full torso ST scans of 100 patients with AIS were analyzed using three-dimensional markerless asymmetry analysis.

OUTCOME MEASURES

Patients with ΔCobb≥5° and ΔCobb<5° were categorized into progression and nonprogression groups, respectively.

METHODS

The ST scan of each full torso was analyzed to calculate the best plane of symmetry by minimizing the distances between the torso and its reflection about the plane of symmetry. Distance between the torso and its reflection was measured and displayed as deviation color maps. The difference of ST measurements between two successive acquisitions was used to determine if the scoliosis has progressed at least 5° or not. The classification tree technique was implemented using the local deformity of the torso in the thoracic-thoracolumbar (T-TL) and lumbar (L) regions to categorize curves into progression and nonprogression groups. The change in maximum deviation and root mean square of the deviations in the torso were the parameters effective in capturing the curve progression. Funding for this research is provided by the Scoliosis Research Society, and Women and Children's Health Research Institute.

RESULTS

The classification model detected 85.7% of the progression and 71.6% of the nonprogression cases. The resulting false-negative rate of 4% for T-TL curves, representing the proportion of undetected progressions, confirmed that the technique shows promise to monitor the progression of T-TL scoliosis curves. Although 100% L curves with progression were detected using the deviation color maps of the torsos, because of the small number of analyzed L curves, further research is needed before the efficiency of the method in capturing the L curves with progression is confirmed.

CONCLUSIONS

Using the developed classification tree for the patients analyzed in this study, 43% of nonprogression cases between two visits would not have to undergo an X-ray examination.

Symmetry analysis of talus bone: A Geometric morphometric approach

OBJECTIVE

The main object of this study was to use a geometric morphometric approach to quantify the left-right symmetry of talus bones.

METHODS

Analysis was carried out using CT scan images of 11 pairs of intact tali. Two important geometric parameters, volume and surface area, were quantified for left and right talus bones. The geometric shape variations between the right and left talus bones were also measured using deviation analysis. Furthermore, location of asymmetry in the geometric shapes were identified.

RESULTS

Numerical results showed that talus bones are bilaterally symmetrical in nature, and the difference between the surface area of the left and right talus bones was less than 7.5%. Similarly, the difference in the volume of both bones was less than 7.5%. Results of the three-dimensional (3D) deviation analyses demonstrated the mean deviation between left and right talus bones were in the range of -0.74 mm to 0.62 mm. It was observed that in eight of 11 subjects, the deviation in symmetry occurred in regions that are clinically less important during talus surgery.

CONCLUSIONS

We conclude that left and right talus bones of intact human ankle joints show a strong degree of symmetry. The results of this study may have significance with respect to talus surgery, and in investigating traumatic talus injury where the geometric shape of the contralateral talus can be used as control. Cite this article: Bone Joint Res 2014;3:139-45.