Radiation-free measurement tools to evaluate sagittal parameters in AIS patients: a reliability and validity study

Noninvasive estimation of internal spinal alignment in patients with adolescent idiopathic scoliosis using PCdare and back shape asymmetry

Optical 3D surface scanning is used increasingly to assess spinal deformity in patients with adolescent idiopathic scoliosis (AIS), largely because it avoids additional radiation burden. However, such approaches generally underestimate the extent of the abnormality. Improving the accuracy of such estimates requires a deeper understanding of AIS and its effect on back shape. We present a unique platform with publicly available code that contains noninvasive and nonionizing approaches to estimating the Cobb angle of the primary curve, called primary Cobb angle (pCA) and internal spinal alignment (ISL) in patients with AIS. Our approaches use asymmetries of the back shape during upright standing, the Adam's forward bending test, bending forward, and lateral bending. The results have revealed strong (0.75 [0.53, 0.87]) to excellent (0.91 [0.81, 0.96]) correlations [95% confidence interval] and a median pairwise absolute error (IQR) of 3.4° (6.8°) between the estimated pCAs and clinical gold-standard assessments in 30 patients. The correlations (IQR) between estimated shape of ISLs and their references were very strong (0.87 (0.24)) to excellent (0.94 (0.03)), and the median root mean square error (IQR) between estimated and reference ISL was 6.9 mm (3.3 mm). These results indicate confidence both in the use of 3D scanning using a "back-shape-to-spine" approach and in the establishment of optical 3D surface scanning approaches for scoliosis screening and monitoring in clinical practice.

Using Surface Topography to Visualize Spinal Motion During Gait-Examples of Possible Applications and All Tools for Open Science

Precise segmental spinal analysis during gait has various implications for clinical use and basic research. Here, we report the use of Surface Topography (ST) to analyze three-dimensional spinal segment movements, in combination with foot pressure measuring, to describe individual vertebral bodies' motion relative to specific phases of gait. Using Statistical Analysis System (SAS) scripts, single files were merged into one raw data table and were used to generate a standardized gait cycle (SGC) for each measurement, including all measured gait cycles for each individual patient, with a spline function to obtain smooth curve progressions. Graph templates from Statistical Package for the Social Sciences create detailed visualizations of the SGCs. Previously obtained measurements from healthy participants were used to demonstrate possible applications of our method. An impressive inter-individual variability as well as intra-individual consistency of spinal motion is shown. The transformation into an SGC facilitates intra- and inter-individual comparisons for qualitative and quantitative analyses. In future studies, we want to use this method to distinguish between physiologic and pathologic spinal motion. Artificial intelligence-based analysis can facilitate this process. All tools and visualizations used are freely available in repositories to enable the replication and validation of our findings.

Validating rasterstereography to evaluate thoracic kyphosis in patients with Scheuermann's disease

PURPOSE

Evaluate the validity of rasterstereography compared to low-dose, biplanar spine radiography for assessing thoracic kyphosis (TK) angles in Scheuermann's disease patients.

METHODS

This prospective study included all the Scheuermann's disease patients consulting our clinic from 2016 to 2018. Recruited patients underwent two-dimensional low-dose biplanar anteroposterior full-length spine radiography and rasterstereography on the same day. Relationships between the TK angles measured were evaluated using Pearson correlation coefficients. Agreement between radiographic and rasterstereographic TK angles was evaluated using two-way intraclass correlation coefficients (ICCs) and Bland-Altman plots. Proportional biases were assessed using the slope regression lines fitted to Bland-Altman plots.

RESULTS

The mean demographic and radiological characteristics of the 52 patients (20 girls; 39%) included were: age 13.1 ± 2 years; BMI 17.3 ± 2.8; and TK max. 50.4° ± 10°. Rasterstereographic TK angles were strongly correlated with radiographic TK angles evaluated from T2-T12 (r = 0.677) and from C7-Max (r = 0.704), with 'good' agreement (ICC > 0.75). A proportional bias was revealed in the slope regression line fitted to the Bland-Altman plot from the C7-Max radiography and the rasterstereography measurements (p = 0.034) but not from the T2-T12 and rasterstereographic TK angles (p = 0.997).

CONCLUSION

Rasterstereography is a reliable means of quantifying TK angles in Scheuermann's disease patients. It could directly reduce the number of radiographic scans patients need over time, minimising their radiation exposure.

Effect of Shoulder Flexion Range of Motion and Trunk Muscle Activity on Lumbar Lordosis in the Streamlined Posture in Healthy Young Men

Objective This study aimed to compare the lumbar spine, pelvic alignment, and trunk muscle activity in healthy participants with and without shoulder flexion restriction in a streamlined posture. Methods The lumbar lordosis angle, pelvic anteversion angle, and trunk muscle activity were measured in 31 young, healthy men in the resting standing position. The streamlined (SL) posture and correlation analysis were performed. Multiple regression analysis was performed to analyze variables that affect the lumbar lordosis angle in the SL posture. Results Correlation analysis revealed that the lumbar lordosis angle in the SL posture had a significant negative correlation with the muscle activity of the internal oblique/transversus abdominis muscle (IO/TrA) during the SL posture (r=-0.37, p<0.045). Multiple regression analysis revealed that lumbar lordosis angle in the SL posture was associated with lumbar lordosis angle in the upright position (β=0.46), IO/TrA activity (β=-0.37), shoulder joint flexion range of motion (β=-0.37), and longissimus dorsi muscle activity during the SL posture (β=-0.28), with a Durbin-Watson statistic adjusted coefficient of determination R2 of 0.67 (p<0.001). Conclusion The lumbar lordosis angle in the SL posture was likely to be high when the range of motion of shoulder joint flexion was small, the activity of the longissimus dorsi muscle in the SL posture was high, and the activity of the IO/TrA was low. This suggests that limited shoulder flexion causes excessive lumbar lordosis, which may be a mechanism of low back pain in swimmers.

The Vehicle Seating Intervention Trial: Cross-Over Randomized Controlled Trial to Evaluate the Impact of 2 Car Seat Configurations on Spinal Posture

Driving posture can lead to musculoskeletal pain. Most work focuses on the lower back; therefore, we know little about automobile seat design and neck posture. This study evaluated an automobile driver seat that individualized upper back support to improve head and neck posture. Specifically, we examined the system's impact on anterior head translation with secondary outcomes of spine posture and perceptions of comfort/well-being compared with a control. Forty participants were block randomized to experience either the activated or deactivated version of the same seating system first. Participants completed two 30-minute simulated driving trials, separated by washout, with continuous measures of anterior head translation, spine posture, and pelvis orientation. Perceptions of comfort/well-being were assessed by survey and open-ended questions immediately following each condition. Small, but statistically significant decreases in anterior head translation and posterior pelvic tilt occurred with the activated seat system. Participants reported lower satisfaction with the activated seat system. Order of the 2 seat conditions affected differences in pelvis orientation and participant perceptions of comfort/well-being. An anthropometric-based seat system targeting upper back support can significantly affect head and pelvic posture but not satisfaction during simulated driving. Future work should examine long-term impacts of these posture changes on health outcomes.

Torsobarography: Intra-Observer Reliability Study of a Novel Posture Analysis Based on Pressure Distribution

Postural deformities often manifest themselves in a sagittal imbalance and an asymmetric morphology of the torso. As a novel topographic method, torsobarography assesses the morphology of the back by analysing pressure distribution along the torso in a lying position. At torsobarography's core is a capacitive pressure sensor array. To evaluate its feasibility as a diagnostic tool, the reproducibility of the system and extracted anatomical associated parameters were evaluated on 40 subjects. Landmarks and reference distances were identified within the pressure images. The examined parameters describe the shape of the spine, various structures of the trunk symmetry, such as the scapulae, and the pelvic posture. The results showed that the localisation of the different structures performs with a good (ICC > 0.75) to excellent (ICC > 0.90) reliability. In particular, parameters for approximating the sagittal spine shape were reliably reproduced (ICC > 0.83). Lower reliability was observed for asymmetry parameters, which can be related to the low variability within the subject group. Nonetheless, the reliability levels of selected parameters are comparable to commercial systems. This study demonstrates the substantial potential of torsobarography at its current stage for reliable posture analysis and may pave the way as an early detection system for postural deformities.

Reference Values for 3D Spinal Posture Based on Videorasterstereographic Analyses of Healthy Adults

Visual examinations are commonly used to analyze spinal posture. Even though they are simple and fast, their interrater reliability is poor. Suitable alternatives should be objective, non-invasive, valid and reliable. Videorasterstereography (VRS) is a corresponding method that is increasingly becoming established. However, there is a lack of reference data based on adequate numbers of participants and structured subgroup analyses according to sex and age. We used VRS to capture the spinal posture of 201 healthy participants (aged 18-70 years) divided into three age cohorts. Three-dimensional reference data are presented for the global spine parameters and for every vertebral body individually (C7-L4) (here called the specific spine parameters). The vertebral column was found to be systematically asymmetric in the transverse and the coronal planes. Graphical presentations of the vertebral body posture revealed systematic differences between the subgroups; however, large standard deviations meant that these differences were not significant. In contrast, several global parameters (e.g., thoracic kyphosis and lumbar lordosis) indicated differences between the analyzed subgroups. The findings confirm the importance of presenting reference data not only according to sex but also according to age in order to map physiological posture changes over the life span. The question also arises as to whether therapeutic approximations to an almost symmetrical spine are biomechanically desirable.

Reliability and Validity of Scoliosis Measurements Obtained with Surface Topography Techniques: A Systematic Review

BACKGROUND

Surface topography (ST) is one of the methods in scoliosis assessment. This study aimed to systematically review the reliability and validity of the ST measurements for assessing scoliosis.

METHODS

A literature search of four databases was performed and is reported following PRISMA guidelines. The methodological quality was evaluated using Brink and Louw appraisal tool and data extraction was performed. The results were analyzed and synthesized qualitatively using the level of evidence method.

RESULTS

Eighteen studies were included and analyzed. Four were evaluated for reliability, six for validity, and eight for reliability and validity. The methodological quality of fourteen studies was high. Good to excellent intra-investigator reliability was shown on asymmetry, sagittal, horizontal, and most frontal ST measurements (evidence level: strong). Asymmetry and most frontal, sagittal, horizontal ST measurements showed good to excellent inter-investigator reliability (evidence level: moderate). When comparing corresponding ST and radiological measurements, good to strong validity was shown on most frontal, sagittal, and asymmetry measurements (evidence level: strong). Formetric measurements had good intra-investigator reliability and validity (evidence level: strong).

CONCLUSIONS

Most asymmetry, sagittal, and frontal ST measurements showed satisfactory reliability and validity. Horizontal ST measurements showed good reliability and poor validity. The ST technique may have great potential in assessing scoliosis, especially in reducing radiation exposure and performing cosmetic assessments.

The Sagittal Integral Morphotype in Male and Female Rowers

The goal of this study was to describe the integrated spinal assessment of the sagittal morphotype in rowers to determine whether the intense practice of rowing causes a modification of the sagittal curvatures of the spine, its relationship with the rowing technique, and training background. The second goal was to analyse how the dorsal and lumbar curves behave in the three phases of the rowing gesture, and to determine which phases can be detrimental to the correct development of the spine during growth. We analysed the spine curvatures in the sagittal plane of 29 females and 82 males, which were measured with an inclinometer in standing, slump sitting, maximal trunk flexion and during rowing performance. The average value of thoracic kyphosis in the rowers was 30° (mean, 30 + 8.27°). Thoracic hyperkyphosis was found in only two rowers (1.8%). Lumbar lordosis was within normal range in 84.1% of the males (mean, 27 + 9.57°) and 75.9% of female rowers (mean, 33°). Functional thoracic hyperkyphosis was observed in 57.4% of the males and 17.1% of the females. Functional lumbar hyperkyphosis was observed in 28 of the 69 males (40.5%) and five of 22 females (17.2%). Rowing seems to provide adequate spine alignment in the sagittal plane on standing. The integrated spinal assessment of the sagittal morphotype showed that half or our rowers presented with functional thoracic hyperkyphosis, and 43.2% presented with functional lumbar hyperkyphosis. Spine behaviour during the rowing technique shows that the thoracic kyphosis (98.2%) and lumbar spine (91%) perform within normative ranges and could explain the adequate positioning of the spine in the sagittal plane on standing. Years of rowing training tend to reduce thoracic kyphosis in males.

Spinal mobility in radiographic axial spondyloarthritis: criterion concurrent validity of classic and novel measurements

Background

Limitations in spinal mobility are a characteristic feature of Axial Spondyloarthritis. Current clinical measurements of spinal mobility have shown low criterion-concurrent validity. This study sought to evaluate criterion-concurrent validity for a clinically feasible measurement method of measuring spine mobility using tri-axial accelerometers.

Methods

Fifteen radiographic-Spondyloarthritis patients were recruited for this study. Two postural reference radiographs, followed by three trials in forward, left and right lateral bending were taken. For all trials, three measurements were collected: tape (Original Schober’s, Modified Schober’s, Modified-Modified Schober’s, Lateral Spinal Flexion Test and Domjan Test), followed immediately by synchronized radiograph and accelerometer measurements at end range of forward and bilateral lateral flexion. The criterion-concurrent validity of all measurement methods was compared to the radiographic measures using Pearson’s correlation coefficients. A Bland-Altman analysis was conducted to assess agreement.

Results

In forward bending, the accelerometer method (r = 0.590, p = 0.010) had a stronger correlation to the radiographic measures than all tape measures. In lateral bending, the Lateral Spinal Flexion tape measure (r = 0.743, p = 0.001) correlated stronger than the accelerometer method (r = 0.556, p = 0.016). The Domjan test of bilateral bending (r = 0.708, p = 0.002) had a stronger correlation to the radiographic measure than the accelerometer method.

Conclusions

Accelerometer measures demonstrated superior criterion-concurrent validity compared to current tape measures of spinal mobility in forward bending. While a moderate correlation exists between accelerometer and radiographs in lateral bending, the Lateral Spinal Flexion Test and Domjan Test were found to have the best criterion-concurrent validity of all tests examined in this study.

Using a dedicated spine radiology technologist is associated with reduced fluoroscopy time, radiation dose, and surgical time in pediatric spinal deformity surgery

STUDY DESIGN

Retrospective comparative study OBJECTIVES: The goal of this study was to investigate fluoroscopy time and radiation exposure during pediatric spine surgery using a dedicated radiology technologist with extensive experience in spine operating rooms. Repetitive use of intraoperative fluoroscopy during posterior spinal fusion (PSF) exposes the patient, surgeon, and staff to radiation.

METHODS

Retrospective review was conducted on patients with posterior spinal fusion (PSF) of ≥ 7 levels for adolescent idiopathic scoliosis (AIS) at a pediatric hospital from 2015 to 2019. Cases covered by the dedicated radiology technologist (dedicated group) were compared to all other cases (non-dedicated group). Surgical and radiologic variables were compared between groups.

RESULTS

230 patients were included. 112/230 (49%) were in the dedicated group and 118/230 (51%) were in the non-dedicated group. Total fluoroscopy time was significantly reduced in cases with the dedicated technologist (46 s) compared to those without (69 s) (p = 0.001). Radiation dose area product (DAP) and air kerma (AK) were reduced by 43% (p < 0.001) and 42% (p < 0.001) in the dedicated group, respectively. The dedicated group also had reduced total surgical time (4.1 vs. 3.5 h; p < 0.001) and estimated blood loss (447 vs. 378 cc (; p = 0.02). Multivariate regression revealed that using a dedicated radiology technologist was independently associated with decreased fluoroscopy time (p = 0.001), DAP (p < 0.001), AK (p < 0.001), surgical time (p < 0.001), and EBL (p = 0.02).

CONCLUSIONS

In AIS patients undergoing PSF, using a dedicated radiology technologist was independently associated with significant reductions in fluoroscopy time, radiation exposure, surgical time, and EBL. This adds to the growing body of research demonstrating that the experience level of the team-not just that of the surgeon-is necessary for optimal outcomes.

LEVEL OF EVIDENCE

III.

Meta-analysis of the validity and reliability of rasterstereographic measurements of spinal posture

OBJECTIVE

We provide a meta-analysis for clinicians and researchers regarding reliability and validity of rasterstereographic measurement of the spinal posture.

METHOD

A comprehensive PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) literature search identified 19 eligible studies evaluating reliability and validity of static rasterstereographic measurements in healthy subjects and patients with different spinal pathologies.

RESULTS

Our meta-analysis suggests that rasterstereography is a reliable and valid instrument to assess spinal posture parameters, especially thoracic kyphosis, lumbar lordosis, and scoliosis, reliability overall effect sizes rs > .91, ps < .001, validity overall effect sizes rs > 70, ps < .001, when compared to traditional radiological imaging techniques. Validity is higher in scoliosis patients compared with healthy controls. Limitations are a lack of reported statistics of the included studies and small sample sizes.

CONCLUSION

The first meta-analysis on reliability and validity of rasterstereography shows satisfactory results. Rasterstereography thus presents a reliable and valid alternative to classic radiological imaging technique to assess and evaluate spinal posture in patients with spinal pathologies. Further studies are needed, focusing on the measurement properties of both static and dynamic rasterstereographic measurements.

Decreased Vertical Trunk Inclination Angle and Pelvic Inclination as the Result of Mid-High-Heeled Footwear on Static Posture Parameters in Asymptomatic Young Adult Women

The influence of high-heel footwear on the lumbar lordosis angle, anterior pelvic tilt, and sacral tilt are inconsistently described in the literature. This study aimed to investigate the impact of medium-height heeled footwear on the static posture parameters of homogeneous young adult standing women. Heel geometry, data acquisition process, as well as data analysis and parameter extraction stage, were controlled. Seventy-six healthy young adult women with experience in wearing high-heeled shoes were enrolled. Data of fifty-three subjects were used for analysis due to exclusion criteria (scoliotic posture or missing measurement data). A custom structured light surface topography measurement system was used for posture parameters assessment. Three barefoot measurements were taken as a reference and tested for the reliability of the posture parameters. Two 30-degree wedges were used to imitate high-heel shoes to achieve a repeatable foot position. Our study confirmed the significant (p < 0.001) reduced vertical balance angle and pelvis inclination angle with large and medium-to-large effects, respectively, due to high-heel shoes. No significant differences were found in the kyphosis or lordosis angles. High-heeled shoes of medium height in young asymptomatic women can lead to a straightening effect associated with a reduced vertical balance angle and decreased pelvic inclination.