The effects of scoliosis and subsequent surgery on the shape of the torso

How Accurate Are Anatomical Surface Topography Parameters in Indicating the Presence of a Scoliosis?

STUDY DESIGN

Retrospective analysis of a longitudinal cohort.

OBJECTIVE

To identify the presence of scoliosis from surface data.

SUMMARY OF BACKGROUND DATA

Identifying AIS can be difficult. Screening is not universal for reasons including high false positive and negative rates. These difficulties can lead to some adolescents missing out on bracing.

METHODS

Logistic regression analysis of ISIS2 surface topography images only was performed. The x,y positions of the shoulders (Sh), axillae (Ax), waist (waist) and the x,y,z positions of the most prominent points over the posterior torso (scap) were used for the thoracic, thoracolumbar/lumbar and whole spine. The models were used to identify the presence of a 20-degree or larger scoliosis. Differences in the position of the landmarks were analyzed comparing left and right, with the suffix "Ht" representing a difference in the y coordinate, "Off" the x coordinate, and "Depth," the z coordinate. Model accuracy was assessed as both percentages and ROC curves with the coefficients as odds ratios.

RESULTS

There were 1283 images (1015 females and 268 males) all with a diagnosis of AIS. The models identified scoliosis in the thoracic spine with an 83% accuracy (AUC 0.91), thoracolumbar/lumbar spine with 74% accuracy (AUC 0.76), and whole spine with 80% accuracy (AUC 0.88). Significant parameters were AxDiffHt, AxDiffOff, WaistDiffHt, ScapDiffOff, and ScapDiffHt for the thoracic curves, AxDiffHt, AxDiffOff, WaistDiffHt for the thoracolumbar/lumbar curves, and AxDiffHt, AxDiffOff, WaistDiffHt and ScapDiffHt for the whole spine.

CONCLUSIONS

The use of fixed anatomical points around the torso, analyzed using logistic regression, has a high accuracy for identifying curves in the thoracic, thoracolumbar/lumbar, and whole spines. While coming from surface topography images, the results raise the future use of digital photography as a tool for the identification of small scoliosis without using other imaging techniques.

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.

Model-Based Radiation-Free Assessment of Scoliosis: A Principle Validation Study

Purpose

Adolescent scoliosis is one of the common pediatric spinal diseases which has a high risk of progression due to the rapid growth of the skeleton during the growing stage therefore needs regular clinical monitoring including X-rays. Because X-rays could lead to ionizing radiation-related health problems, an ionizing radiation-free, non-invasive method is presented here to estimate the degree of scoliosis and to potentially support the medical assessment.

Methods

The radiation-free body scanner provides a 3D surface scan of the torso. A basic 3D structure of the human ribcage and vertebral column was modeled and simulated with computer-aided design software and finite element method calculation. For comparison with X-rays, courses of vertebral columns derived from 3D torso images and 3D models were analyzed with respect to their apex positions and angles.

Results

The methods show good results in the estimation of the apex positions of scoliosis. Strong correlations (R = 0.8924) were found between the apex and Cobb angle from X-rays. Similar correlations (R = 0.8087) was obtained between the apex angles extracted from X-rays and the combination of torso scan images with 3D model simulations. Promising agreement was obtained between the spinal trajectories extracted from X-ray and 3D torso images.

Conclusions

Very strong correlations suggest that the apex angle could potentially be used for scoliosis assessment in follow-up examinations in complement to the Cobb angle. However, further improvements of the methods and tests on a larger number of data set are necessary before their introduction into the clinical application.

The use of statistical modelling to identify important parameters for the shape of the torso following surgery for adolescent idiopathic scoliosis

The surgical strategy in adolescent idiopathic scoliosis (AIS) aims to recreate the symmetry of the torso. This requires the minimisation of both the size of the scoliosis and the angulation between the sides of the torso, along with the recreation of a normal thoracic kyphosis. This study uses predictive modelling to identify the significance of the value of the pre-operative parameters, and the change in the magnitude of the parameters as a result of an operation on the shape of the torso using the 'most prominent points'; two areas of maximum prominence on either side of the spine with x, y and z coordinates. The pre-operative values, and the change in magnitude between the pre and post-operative values, for scoliosis, kyphosis and skin angulation from a group of Lenke 1 convex to the right AIS were analysed with measures collected using Integrated Spine Imaging System 2 surface topography and compared with those without visible spinal deformity. The models best explained the z coordinate and least well explained the x coordinate, although there was a contribution to all of the models that remained unexplained. The parameters that affected the position of the coordinates in the model differed between the models. This confirms that surgically altering the shape of the spine and torso whilst correcting an AIS does not lead to a symmetrical torso. There are as yet, undefined factors which contribute to the shape of the torso and which if identified and corrected surgically would lead to greater symmetry post-operatively.

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.

The resting coronal and sagittal stance position of the torso in adolescents with and without spinal deformity

The purpose of this work is to identify the resting stance of the torso, defined as the position of the C7 vertebral body relative to the sacrum in a ‘birds eye view’, as the coronal and sagittal offset, in those without spinal deformity, those with pre and post-operative AIS, and those with Scheuermann's kyphosis (SK). Using ISIS2 surface topography, the coronal and sagittal offset were measured in a prospective manner in all groups. With bivariate ellipses, a mean and 95% confidence ellipse of the data was developed. Statistical analyses was performed to examine the distribution of the data from the groups. A graphical representation of the data was developed. There were 829 without spinal deformity, 289 in both the pre and post-operative with AIS and 59 with SK. The results showed that the mean coronal offset for all groups was between 2 and 6 mm and the sagittal offset was 12 and 26 mm. Statistically significance was seen for both measures between the non-scoliotic and both AIS groups, along with the pre-operative AIS coronal offset and post-operative AIS sagittal offset and the SK measures. However, all mean values were within the 95% confidence ellipse for all of the groups. Regardless of the size or type of spinal deformity, the position of the C7 vertebral body and sacrum remain within the 95% confidence ellipse of that seen in those without spinal deformity. This work defines the Minimally Clinically Important Difference for all of the groups.

The variability in location of the most prominent points on the posterior torso of those without abnormal surface topography, those with Adolescent Idiopathic Scoliosis and those with Scheuermann's Kyphosis: a seven year longitudinal analysis

The correction of adolescent scoliosis involves the recreation of torso symmetry. A symmetrical torso has equivalent areas of shape on either side of the midline. The posterior torso has two areas of prominence, known as the 'most prominent points' on either side of the midline which can be used as reference points to measure symmetry of the posterior torso. This study used the three-dimensional (3D) coordinates of the most prominent points, measured using ISIS2 surface topography and standardised by torso size, in children without abnormal surface topography, with adolescent idiopathic scoliosis (AIS) (right thoracic curves) and with Scheuermann's kyphosis (SK). The purpose was to demonstrate the variability of the position of the points in these three groups. The variability of the 3D coordinates was calculated for each group (mean, standard deviation and range in millimetres) and the standardised data were illustrated using 3D 95% confidence interval ellipsoids. In those without deformity, the position of the left and right point was mirrored with little difference. The AIS group showed a difference between the left and right points, with the right becoming further from the midline and more prominent than the left but with the left becoming more superior than the right. For the SK cohort, both left and right points moved inwards towards the midline and became more prominent. Linear mixed effect modelling was used to examine the contribution of age, kyphosis and scoliosis to the position of the most prominent points. In the cohort without abnormal surface topography, the x parameter increases with the covariates of age and kyphosis, with the covariate of age likely reflecting torso growth. The left side becomes more prominent and inferior compared to the right. In the AIS cohort, age follows the cohort without abnormal surface topography. This is added to by the scoliosis which is observed to make the right side more lateral, less inferior and more prominent, whereas the left becomes more medial, less inferior and less prominent. Kyphosis in the AIS cohort leads to the right point becoming more lateral, less inferior and less prominent whereas in the left becomes more lateral, more inferior and more prominent. In the SK cohort, the effects of the covariates of age and kyphosis are not clear reflecting the small number of cases with more than one surface topography image over time.

A report of the number of adolescents screened as warranting further investigation for depression and social anxiety in a pre-operative cohort with idiopathic scoliosis

INTRODUCTION

Adolescent Idiopathic Scoliosis (AIS) is a common form of scoliosis, causing rotational deformity of the torso in a teenage population. In AIS this happens at a time of particular psychological development and vulnerability and a link between AIS and mental health problems has been observed.

MATERIALS AND METHODS

Over a 6 month period, all patients with AIS aged 10-18 referred to a single spinal deformity centre in the UK were screened for symptoms suggestive of a potential diagnosis of depression and social anxiety.

RESULTS

Of the 33 patients surveyed, 6 (18%) had scores worthy of further assessment for a potential diagnosis of depression and 19 (59%) worthy of further assessment for a potential diagnosis of social anxiety.

DISCUSSION AND CONCLUSION

This small study supports the notion that there is an association between AIS and mental health issues. These initial findings support the practice of routine mental health screening in AIS.

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.

Self-Experienced Trunk Appearance in Individuals With and Without Idiopathic Scoliosis

STUDY DESIGN

Cross-sectional.

OBJECTIVE

The aim of this study was to describe the self-experienced trunk appearance in individuals with and without idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

Idiopathic scoliosis is the most common spinal deformity. A large scoliotic deformity increases the risk of back pain and pulmonary dysfunction. The deformity has also a psychological impact.

METHODS

The pictorial part of the spinal appearance questionnaire (pSAQ) was administered to 1416 individuals with idiopathic scoliosis (386 untreated, 529 brace treated, 501 surgically treated) and 272 individuals without scoliosis from the general population. Comparisons were made between individuals with and without scoliosis, between treatment groups and sex in the scoliosis group.

RESULTS

Mean (95% confidence interval) age of the individuals with scoliosis was 36.2 (35.5-36.9) years and for the individuals without scoliosis 40.2 (37.9-42.4). pSAQ total was 12.3 (12.1-12.5) for individuals with scoliosis and 7.4 (7.3-7.6) for individuals without scoliosis (P < 0.001, adjusted for age and sex). pSAQ total was 11.5 (11.1-11.9) for untreated, 13.0 (12.6-13.3) for brace treated, and 12.3 (11.9-12.6) for surgically treated individuals (P < 0.001, adjusted for sex and curve size). The pSAQ total between males and females with idiopathic scoliosis did not differ (P = 0.22 adjusted for age and curve size).

CONCLUSION

This study shows that individuals with idiopathic scoliosis have more concern about their body appearance than individuals without scoliosis. Untreated individuals are not as bothered of their spinal appearance as treated individuals. Males and females with scoliosis do not differ significantly in the perception of their spinal appearance.

LEVEL OF EVIDENCE

3.

What Constitutes Shoulder Imbalance in Adolescent Idiopathic Scoliosis? Aesthetic Threshold for Surgical Correction

OBJECTIVE

To determine what constitutes clinical shoulder imbalance and the aesthetic unsightliness of the torso region in patients with scoliosis. How can it be measured? Shoulder imbalance is one of the most perplexing problems in scoliosis. There are no standard clinical or radiologic criteria for diagnosing shoulder imbalance, and hence its impact and prevention are poorly understood. This prospective cohort study aims to determine the clinical parameters in the torso region that are most aesthetically disfiguring in scoliosis, and the measures with their threshold values that can define shoulder imbalance.

METHODS

Twenty-six consecutive patients with adolescent idiopathic scoliosis formed the patient cohort. Only preoperative clinical photographs (not x-rays) of these patients were used for the study. Forty random observers were asked to rate the shoulder disfigurement in these patients as acceptable or unacceptable. An independent researcher plotted and measured 10 different deformity markers on these photographs. Three regions of the torso, the neck, shoulder, and axillary region, were studied separately. Receiver operating characteristic analysis was used to determine significance of each measure.

RESULTS

The patients with unacceptable deformation had statistically significant values in each of the 3 regions. The patients with acceptable appearance also had several measures that proved significant. Threshold values for each of these parameters were established from the analysis.

CONCLUSIONS

Shoulder imbalance in scoliosis is defined based on 3 regions: the neck, shoulder, and axillary region. Each has a specific threshold for producing cosmetically unacceptable deformation and they can be measured on clinical photographs. Measurement of the shoulder level alone is less representative.

A Noninvasive 3D Body Scanner and Software Tool towards Analysis of Scoliosis

Purpose

Children with neurological disorders, such as cerebral palsy (CP), have a high risk of developing scoliosis during growth. The fast progression of scoliosis implies in several cases frequent clinical and X-ray examinations. We present an ionizing radiation-free, noncontacting method to estimate the trajectory of the vertebral column and to potentially facilitate medical diagnosis in cases where an X-ray examination is not indicated.

Methods

A body scanner and corresponding analysis software tools have been developed to get 3D surface scans of patient torsos and to analyze their spinal curvatures. The trajectory of the vertebral column has been deduced from the body contours at different transverse sectional planes along the vertical torso axis. In order to verify the present methods, we have analyzed twenty-five torso contours, extracted from computer tomography (CT) images of patients who had a CT scan for other medical reasons, but incidentally also showed a scoliosis. The software tools therefore process data from the body scanner as well as X-ray or CT images.

Results

The methods presented show good results in the estimations of the lateral deviation of the spine for mild and moderate scoliosis. The partial mismatch for severe cases is associated with a less accurate estimation of the rotation of the vertebrae around the vertical body axis in these cases. In addition, distinct torso contour shapes, in the transverse sections, have been characterized according to the severity of the scoliosis.

Conclusion

The hardware and software tools are a first step towards an ionizing radiation-free analysis of progression of scoliosis. However, further improvements of the analysis methods and tests on a larger number of data sets with diverse types of scoliosis are necessary, before its introduction into clinical application as a supplementary tool to conventional examinations.

A Description of Three-Dimensional Shape of the Posterior Torso Comparing Those with and without Scoliosis

Scoliosis results in a 3D asymmetry of the spine and torso. It is not clear what the variability in 3D shape is in a non-scoliotic population, how much that is altered by scoliosis and what surgery does to that. This study is a 3D analysis of the shape of the torso in a cohort of non-scoliotic children that is then compared with a cohort of those with scoliosis both pre- and post-operatively. Procrustes analysis is used to examine the mean 3D shape. There is variability in shape in the non-scoliotic cohort. Scoliosis increases this asymmetry, particularly around the most prominent areas of the torso. Surgery alters the torso asymmetry but increases the difference in height between the right and the left with regard to the most prominent points on the torso. There is a degree of asymmetry seen in a non-scoliotic cohort of children. Scoliosis increases that asymmetry. Surgery alters the asymmetry but causes an increase in some of the 3D elements of the most prominent areas of the torso.