Back Surface Topography Research Articles

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.

Comparison between radiographic and ultrasound angle measurements in the assessment of idiopathic scoliosis

<p>Introduction. Radiological assessment is still being considered a golden standard when it comes to detection, follow-up and treatment of idiopathic scoliosis. However, it has universally been proven that radiation is cumulative and that it has oncogenic effects. For this reason, nowadays it is becoming increasingly popular to perform spinal ultrasounds using the Scolioscan® device. Relevant research has shown diagnostic potential of the device and its application in the assessment and monitoring of idiopathic scoliosis. The aim of our study has been to compare angle measurements in ultrasound and radiological spinal images and to determine the role of ultrasound in the assessment process and follow-up of patients with idiopathic scoliosis. Methods. This cross-sectional study has been conducted on a sample of 172 patients. Its participants are boys and girls, patients of the Team for Scoliosis that operates within the Department for Habilitation and Rehabilitation of Children in the Institute for Physical Medicine and Rehabilitation ''Dr Miroslav Zotović'', Banja Luka, the Republic of Srpska. Radiography and ultrasound of the spine have been performed on every patient on the same day. Three specially trained operators administrated the ultrasound scanning, while four raters (i.e. doctors) measured the radiographic Cobb angle and the ultrasound Scolio angle. Patients have been divided into groups according to gender, curve location and curve severity. Results. In general, ultrasound angles are shown to be smaller compared to Cobb angles, which has been confirmed in previous studies as well. The mean difference between Cobb and Scolio angle is statistically, but not clinically significant (3.62±4.39°, p<0.001). There is a statistically significant good positive correlation between the Cobb and the Scolio angle (r=0.675, p<0.001). According to groups, our results indicate a better correlation in the girls group (r=0.688, p<0.001) as opposed to the boys group (r=0.632, p<0.001). The same holds true for the thoracic group (r=0.736, p<0.001), compared to the (thoraco) lumbar group (r=0.654, p<0,001). A stronger correlation can also be seen in the group with a Cobb angle that is equal to or higher than 20° (r=0.518, p<0.05) than in the group with a Cobb angle lower than 20° (r=0.462, p<0.001). Conclusion. The results of our study confirmed a good validity of the ultrasound method using the Scolioscan® device, compared to conventional radiography, taking into account clinically insignificant differences in angle measurements. Using only B-mode ultrasound images - with no additional software analysis, nor 3D reconstruction of spinal deformities - proved to be sufficient for a follow-up of scoliosis, with respect to other parameters, such as clinical assessment, back surface topography, etc.</p>

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

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

Coronal plane trunk asymmetry is associated with whole-body sagittal alignment in healthy young adolescents before pubertal peak growth.

To investigate coronal plane trunk asymmetry (TA) and its association with sagittal postural alignment in healthy subjects before pubertal peak growth. In this cross-sectional baseline study, 1190 healthy pre-peak growth velocity subjects were included. Coronal plane TA was evaluated using back surface topography. Whole-body sagittal alignment (previously validated and objectively classified as neutral, sway-back or leaning-forward) and sagittal spinopelvic profile (trunk lean, lumbar lordosis, thoracic kyphosis, sacral inclination and length of the posteriorly inclined thoracolumbar segment) were determined, as were height, proportion of trunk to body length, body mass index, generalized joint laxity, and handedness. Logistic regression analysis yielded overall sagittal posture class to be independently associated with coronal plane TA: having a leaning-forward posture associated with a nearly three times higher odds of coronal TA (p<0.001) compared to neutrals. A sway-back was 2.2 times more likely to show TA (p=0.016) than a neutral, yet only in boys. Significant associations with coronal TA were also found for trunk lean, thoracic kyphosis and body mass index. These correlations, however, were gender and posture class specific. The spinal region where asymmetry is seen, varies according to the whole-body sagittal alignment type: primary thoracic curves were the most frequent in leaning-forwards, whereas primary curves in the lumbar or declive thoracolumbar segment were the most common in sway-backs. In immature spines without known scoliosis, coronal plane TA is associated with whole-body sagittal alignment. It is more often seen in non-neutral than neutral sagittal posture types. Whether adolescent idiopathic scoliosis is related with postural characteristics before pubertal growth peak, should be addressed in future prospective studies.

Correlation between Topographic Parameters Obtained by Back Surface Topography Based on Structured Light and Radiographic Variables in the Assessment of Back Morphology in Young Patients with Idiopathic Scoliosis.

Study DesignOptical cross-sectional study.PurposeTo study the correlation between asymmetry of the back (measured by means of surface topography) and deformity of the spine (quantified by the Cobb angle).Overview of LiteratureThe Cobb angle is considered the gold standard in diagnosis and follow-up of scoliosis but does not correctly characterize the three-dimensional deformity of scoliosis. Furthermore, the exposure to ionizing radiation may cause harmful effects particularly during the growth stage, including breast cancer and other tumors.MethodsPatients aged 13.15±1.96 years (range, 7–17 years; n=88) with Cobb angle greater than 10° were evaluated with X-rays and our back surface topography method through three variables: axial plane (DHOPI), coronal plane (POTSI), and profile plane (PC). Pearson's correlation was applied to determine the correlation between topographic and radiographic variables. One-way analysis of variance and Bonferroni correction were used to compare groups with different grades of scoliosis. Significance was set at p<0.01 and, in some cases, at p<0.05.ResultsWe detected a positive, statistically significant correlation between Cobb angle with DHOPI (r=0.810) and POTSI (r=0.629) and between PC variables with thoracic kyphosis angle (r=0.453) and lordosis lumbar angle (r=0.275). In addition, we found statistically significant differences for DHOPI and POTSI variables according to the grade of scoliosis.ConclusionsAlthough the back surface topography method cannot substitute for radiographs in the diagnosis of scoliosis, correlations between radiographic and topographic parameters suggest that it offers additional quantitative data that may complement radiologic study.

Clinical application of back surface topography by means of structured light in the screening of idiopathic scoliosis.

We present the results of the clinical validity in the screening of idiopathic scoliosis with a nonharming method of back surface topography by means of structured light projection. A total of 155 patients were evaluated (mean age 13.3 years). They were divided into two groups: pathologic patients (scoliosis) and nonpathologic patients (control and asymmetries). An analytical case-control study was carried out. Our topographic method obtained 92% sensitivity and 74% specificity as a screening test in identifying patients with scoliosis (P=0.05). We could quantify the vertebral deformity of scoliosis in the three spatial planes by means of three topographic variables, Horizontal Plane Deformity Index, Posterior Trunk Symmetry Index and Columnar Profile, and to elaborate a combined screening algorithm with good reliability parameters.

Quantification of topographic changes in the surface of back of young patients monitored for idiopathic scoliosis: correlation with radiographic variables.

Idiopathic scoliosis requires a close follow-up while the patient is skeletally immature to detect early progression. Patients who are monitored by radiographs are exposed to high doses of ionizing radiation. The purpose of this study is to evaluate if an optic noninvasive method of back surface topography based on structured light would be clinically useful in the follow-up of young patients with idiopathic scoliosis. This could reduce the number of radiographs made on these children. Thirty-one patients with idiopathic scoliosis were submitted twice to radiograph and our topographic method at intervals of 6 months to 1 year. Three topographical variables were applied horizontal plane deformity index (DHOPI), posterior trunk symmetry index (POTSI), and columnar profile (PC). A statistically significant correlation was found between variations of Cobb angle with DHOPI (r=0.720, p<0.01) and POTSI (r=0.753, p<0.01) during the monitoring period. Hence, this topographic method could be useful in clinical practice as an objective adjuvant tool in routine follow-up of scoliosis.

Monitoring of progressive idiopathic scoliosis by BIOMOD TM-L, back surface topography device, during plaster treatment and progressive felting

No irradiant techniques of analysis of deformations of the spine, by surface topography, have been developed with a view to detecting scoliosis and monitoring its progression during growth. The objective of our work was to study the evolution of back surface topography parameters by BIOMOD TM-L in adolescents with idiopathic scoliosis treated with plaster and progressive felting. Children with severe idiopathic scoliosis, for which a plaster more felting treatment before a brace was indicated, and has received a topographic and radiological acquisition before and after the realization of plaster, and up to one year after the start of treatment, were included. The main endpoint was the change of thoraco-lumbar variable in the transverse plane measured by BIOMOD TM-L at T0 (before felting), T1 (after felting) and T2 (one year before the beginning of treatment). Twenty-one children (mean age: 13) were included. There is a significant decrease of the thoraco-lumbar gibbosity measure by BIOMOD TM-L in adolescent with scoliosis treated with plaster more felting, at T0, T1 and T2 ( P = 0.0007). The medians of these gibbosity were of 8,0° (IC 95% [6,15–8,73]), 4,0° (IC 95% [3,37–5,88], rank sum diff = 20) ( P adjusted = 0.0008), and 4,0° (IC 95% [3,64–5,98], rank sum diff = 16) ( P adjusted = 0.0094), respectively at T0, T1 and T2. These results are also checked for gibbosity measured clinically by scoliometer, with a significant decrease up to one year after the start of treatment. However, there is no significant difference at one year for the Cobb angle. The treatment with plaster more felting in the adolescent idiopathic scoliosis enables a significant reduction of the clinical rib hump and measured by back surface topography, and up to one year after the start of treatment.

Rasterstereographic measurement of scoliotic deformity.

BackgroundBack surface topography has gained acceptance in recent decades. At the same time, the motivation to use this technique has increased. From the view of the patient, the cosmetic aspect has played and still plays a major role as it provides a comprehensive documentation of cosmetic impairment. From the view of the medical practitioner, the aspect of reducing X-ray exposures in diagnosis and follow-up has been dominant and still prevails. Meanwhile, new aspects have emerged: due to the consequent three-dimensional view of the scoliotic condition, treatment success can be visualized convincingly. Clinical diagnosis is supported by information otherwise not supplied by X-rays, such as when functional examinations and diagnostic tests are recorded.MethodsLike rasterstereography, most techniques of actual back surface measurement refer to photogrammetry and the triangulation method. However, with respect to the particular clinical application, a wide spectrum of implementations exists. Applications in a clinic require high accuracy of measurement in a short time and comprehensive analysis providing data to be used to supplement and compare with radiographic data. This is exemplified by rasterstereography; the procedures of surface analysis and localization of landmarks using curvatures and the reconstruction of the spinal midline will be described.Orthopaedic relevanceBased on rasterstereographic analysis, different geometrical measures that characterize the back surface are given and underlying skeletal structures described. Furthermore, in analogy to radiological projection, a 3-D reconstruction of the spinal midline is visualized by a frontal and lateral projection, allowing comparison with pertinent X-rays.ConclusionsSurface topography and, in particular, rasterstereography provide reliable and consistent results that may be used to reduce X-ray exposure. Unfortunately, the correlation of shape parameters with the radiological Cobb angle is poor. However, the wealth of additional applications substantially enhances the spectrum of clinical value.

Detection of progressive idiopathic scoliosis during growth using back surface topography: A prospective study of 100 patients

The progression of adolescent idiopathic scoliosis is typically monitored via regular radiographic follow-up. The Cobb angle (as measured on whole-spine radiographs) is considered as the gold standard in scoliosis monitoring. ObjectiveTo determine the sensitivity and specificity of back surface topography parameters, with a view to detecting changes in the Cobb angle. Patient and methodOne hundred patients (mean age: 13.3) with Cobb angles greater than 10 degrees were included. Topographic parameters were measured in a standard position and in a position with hunched shoulders. Gibbosities and spinal curvatures were evaluated. ResultsAn increase of more than 2 degrees in any one gibbosity or in the sum of the gibbosities (in either of the two examination positions) enabled the detection of a five-degree increase in the Cobb angle with a sensitivity of 86% and a specificity of 50%. ConclusionIf the present results are confirmed by other studies, analysis with back surface topography parameters may reduce the number of X-ray examinations required to detect increases in the Cobb angle.

The Time Effectiveness of Three-Dimensional Telediagnostic Postural Screening of Back Curvatures and Scoliosis

Postural screening remains a powerful tool that can be used to identify children and adolescents with scoliosis or sagittal plane deformities. The aim of this study was to assess the time effectiveness of implemented telediagnostic screening procedures. Medical images (virtual objects) of acquired clouds of points of 100 subjects of both sexes were chosen at random from the database and used for parametric evaluation for this study. This study was performed using a newly developed three-dimensional (3D) back surface topography measurement system for posture and scoliosis using a structured light method. The duration of each step of therapist/nurse/physician-assisted 3D assessment was measured independently with a stopwatch. Two configurations of PC computers and Internet connections were used to test the time effectiveness. Scoliotic postures were detected using cutoff values of angle of trunk rotation, Posterior Trunk Symmetry Index, and Deformity in the Axial Plane Index indices. The overall assessment of all subjects consumed from 2 h 55 min 55 s to 3 h 18 min 59 s dependent on PC and Internet connection configuration. Average examination time per subject ranged from 2 min 43 s to 4 min 51 s, respectively. The virtual landmarking and report generation times were dependent on the PC configuration (p<0.001). Our study confirmed satisfactory time effectiveness of the implemented telediagnostic postural screening procedure. We assume that it may influence the cost-effectiveness of the screening, which is usually mentioned as an important factor for recommendations against postural school screening. Relatively fast Internet connection and a medium-level PC configuration are sufficient for achieving a reasonably short time of 3D posture assessment of a virtual object representing a real subject's back surface. The efficiency of remote assessment of exact 3D surface topography can be used in large-scale studies for posture and scoliosis epidemiology.

Inter-observer reproducibility of back surface topography parameters allowing assessment of scoliotic thoracic gibbosity and comparison with two standard postures

The objective of this work was to analyze the inter-observer reproducibility of an upright posture designed to bring out the thoracic humps by folding the upper limbs. The effect of this posture on back surface parameters was also compared with two standard radiological postures. A back surface topography was performed on 46 patients (40 girls and 6 boys) with a minimum of 15° Cobb angle on coronal spinal radiographs. Inter-observer reliability was evaluated using the typical error measurement (TEM) and Intraclass Correlation Coefficient (ICC). Variations between postures were assessed using a Student's t test. The inter-observer reproducibility is good enough for the three postures. The proposed posture leads to significant changes in the sagittal plane as well as in the identification of thoracic humps. This study shows the reproducibility of the proposed posture in order to explore the thoracic humps and highlights its relevance to explore scoliosis with back surface topography systems.

Automatic recognition of surface landmarks of anatomical structures of back and posture

Faulty postures, scoliosis and sagittal plane deformities should be detected as early as possible to apply preventive and treatment measures against major clinical consequences. To support documentation of the severity of deformity and diminish x-ray exposures, several solutions utilizing analysis of back surface topography data were introduced. A novel approach to automatic recognition and localization of anatomical landmarks of the human back is presented that may provide more repeatable results and speed up the whole procedure. The algorithm was designed as a two-step process involving a statistical model built upon expert knowledge and analysis of three-dimensional back surface shape data. Voronoi diagram is used to connect mean geometric relations, which provide a first approximation of the positions, with surface curvature distribution, which further guides the recognition process and gives final locations of landmarks. Positions obtained using the developed algorithms are validated with respect to accuracy of manual landmark indication by experts. Preliminary validation proved that the landmarks were localized correctly, with accuracy depending mostly on the characteristics of a given structure. It was concluded that recognition should mainly take into account the shape of the back surface, putting as little emphasis on the statistical approximation as possible.

Effect of the back surface topography on the efficiency in silicon solar cells

Different processes are used on the back surface of silicon wafers to form cells falling into three groups: textured, planar, and sawed-off pyramid back surface. The characteristic parameters of the cells, ISC, VOC, FF, Pm, and Eff, are measured. All these parameters of the planar back surface cells are the best. The FF, Pm, and Eff of sawed-off pyramid back surface cells are superior to textured back surface cells, although ISC and VOC are lower. The parasitic resistance is analyzed to explain the higher FF of the sawed-off pyramid back surface cells. The cross-section scanning electron microscopy (SEM) pictures show the uniformity of the aluminum–silicon alloy, which has an important effect on the back surface recombination velocity and the ohmic contact. The measured value of the aluminum back surface field thickness in the SEM picture is in good agreement with the theoretical value deduced from the Al–Si phase diagram. It is shown in an external quantum efficiency (EQE) diagram that the planar back surface has the best response to a wavelength between 440 and 1000 nm and the sawed-off back surface has a better long wavelength response.

Un nuevo sistema de topografía de superficie de la espalda: fotogrametría digital. Fundamento, procedimiento y aplicación clínica cualitativa

Introduction Some of the most known back surface topography methods are based on a structured light focus. This study aims to present a new method that uses a conventional light source to obtain an image which is then analyzed by digital photogrametry. Material and method The law that defines the variations of object luminance with the distance that separates it from a focus and that explains the differences in color intensity of an image is described. Digitalization of these values makes it possible to perform a computer analysis. The sample studies was made up of 17 persons: 9 patients with scoliosis, 6 with leg-length discrepancy and 2 healthy volunteers. A comparative qualitative study was made of the normal image, photogrametry and X-ray. Results Eleven women and 6 men, mean age 21 years, were studied. the normal group was characterized by the homogeneity of the color curves on both sides of the middle line. The group with dysmetria had asymmetry of the iliac posterior region. The unequal distribution of the color curves in each hemitrunk stood out in the group with idiopathic scoliosis. Discussion This system is in a preliminary phase of development and quantitative data are still not available. However, it offers an image emphasizing asymmetries efficiently, using simple procedures. The development of this technique should be aimed at measuring the back volume and its lateral asymmetries.

Biomechanical Testing and Scoliosis

Patients with scoliosis deformity can be evaluated from a biomechanical viewpoint by measurement of spinal morphology, back surface topography, and changes in these measurements both acutely and over time. In addition, the forces acting on the spine can be estimated in vivo. Many ethical and practical challenges have been overcome, and these measurement techniques have provided information on spinal deformity and its treatment. Further insights have come from biomechanical analyses of these measurements, and complementary modeling studies. This study reviews the available methodologies and the progress that has been made toward using these methods in assessing outcomes in treatment. Possible future directions for in vivo measurements are suggested for studies of etiology, growth regulation, progression of deformity, three-dimensional assessment of treatment outcome, and monitoring of individual patients.