Assessment of reliability and validity of a handheld surface spine scanner for measuring trunk rotation in adolescent idiopathic scoliosis

PURPOSE

To assess the reliability and validity of a handheld scanner (SpineScan3D) for trunk rotation measurement in adolescent idiopathic scoliosis (AIS) subjects, as compared with Scoliometer.

METHODS

This was a cross-sectional study with AIS subjects recruited. Biplanar spine radiographs were performed using an EOS imaging system with coronal Cobb angle (CCA) determined. The angle of trunk rotation (ATR) was measured using Scoliometer. SpineScan3D was employed to assess the axial rotation of subjects' back at forward bending, recorded as surface tilt angle (STA). Intra- and inter-examiner repeats were conducted to evaluate the reliability of SpineScan3D.

RESULTS

97 AIS patients were recruited. Intra- and inter-examiner reliability of STA measures were good to excellent in major thoracic and lumbar curves (p < 0.001). A strong correlation was found between STA and ATR measures in both curve types (p < 0.001) with a standard error of the ATR estimate of between 1 and 2 degrees from linear regression models (R squared: 0.8-0.9, p < 0.001). A similar correlation with CCA was found for STA and ATR measures (r: 0.5-0.6, p < 0.002), which also demonstrated a similar sensitivity (72%-74%) and specificity (62%-77%) for diagnosing moderate to severe curves.

CONCLUSION

SpineScan3D is a handheld surface scanner with a potential of wide applications in subjects with AIS. The current study indicated that SpineScan3D is reliable and valid for measuring trunk rotation in AIS subjects, comparable to Scoliometer. Further studies are planned to investigate its measurements in coronal and sagittal planes and the potential of this device as a screening and monitoring tool.

TRIAL REGISTRATION NUMBER (DATE OF REGISTRATION)

HKUCTR-2288 (06 Dec 2017).

LEVEL OF EVIDENCE

Level III.

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.

Application of two-parameter scoliometer values for predicting scoliotic Cobb angle

BACKGROUND

Adolescent idiopathic scoliosis, in which obvious curves are visible in radiographic images, is also seen in combination with lumps in the back. These lumps contribute to inclination, which can be measured by a scoliometer. To the authors' knowledge, there are no previous formulas combining thoracic and lumbar scoliometer values simultaneously to predict thoracic and lumbar Cobb angles, respectively. This study aimed to create more accurate two-parameter mathematical formulas for predicting thoracic and lumbar Cobb angles.

METHODS

Between Dec. 2012 and Jan. 2013, patients diagnosed with idiopathic scoliosis in an outpatient clinic were enrolled. The maximal trunk rotations at the thoracic and lumbar regions were recorded with a scoliometer. Right asymmetry hump was deemed positive (+), and left asymmetry hump was deemed negative (-). The Cobb angles were measured with a Picture Archiving and Communication System. Statistical analysis included Pearson's correlation coefficient, multivariate regression and Bland-Atman analysis.

RESULTS

One-hundred and one patients were enrolled in our study. The average thoracic curve (TC) was 23.3 ± 1.8°, while the average lumbar curve (LC) was - 23.3 ± 1.4°. The thoracic inclination (TI) and lumbar inclination (LI) were 4.5 ± 0.7 and - 5.9 ± 0.6, respectively. The one-parameter formula for the thoracic curve was TC = 2.0 TI + 14.3 (r = 0.813); for the lumbar curve, it was LC = 0.9 LI - 16.9 (r = 0.409). By multivariate regression, the two-parameter formulas for the thoracic and lumbar curves were TC = 2.6 TI - 1.4 LI (r = 0.931) and LC = - 1.5 TI + 2.0 LI (r = 0.874), respectively. The two-parameter formulas were more accurate than the one-parameter formulas.

CONCLUSIONS

Based on the results of these two-parameter formulas for thoracic and lumbar curves, the Cobb angles can be predicted more accurately by the readings of the scoliometer. Physicians and other healthcare practitioners can thus evaluate patients with scoliosis more precisely than before with a scoliometer.

The effect of sublaminar wires on the rib hump deformity during scoliosis correction manoeuvres

INTRODUCTION

During thoracic curve correction, the tightening of the sublaminar wires through concavity creates a medial and a dorsal translation of the spine. However, little is known about the effect of the sublaminar wires on the axial plane.

METHODS

This is prospective case series analysis of 30 consecutive surgical patients with main thoracic adolescent idiopathic scoliosis. All of the patients were fused with hybrid instrumentation (apical concavity-sublaminar wires) and differential rod contouring (over-kyphosis concavity/under-kyphosis convexity). The degrees of the rib hump were measured with a scoliometer placed at the apex of the deformity at five different times: (1) preoperatively through the Adam's test, and during surgery (sterilised scoliometer), (2) with the patient lying prone, (3) after the Ponte osteotomies, (4) after the apical sublaminar tightening, and (5) after convexity apical derotation and compression manoeuvres.

RESULTS

(1) Preoperatively, the Adam's test was 16.3° ± 4.6. (2) Lying prone and under general anaesthesia, it decreased to 11.4° ± 3.9. (3) After exposure and Ponte osteotomies, it was 7.1° ± 4. (4) After the wire tightening, it was 10.8° ± 4.7. (5) After the convexity manoeuvres, it was 4.8° ± 3.7. The degrees of the rib hump final correction were 11.6° ± 4 (70 % correction). The tightening of the sublaminar wires increased the rib hump by 3.5°.

CONCLUSIONS

The sublaminar wire tightening towards the concave rod seemed to create an effect opposite of the desired effect, increasing the apical rotation and the thoracic rib hump deformity. Convexity manoeuvres (apical screw derotation and compression) are necessary and must be coupled with an under-bending of the convex rod to neutralise this effect.

Idiopathic Scoliosis Prevalence Is 5 Times Less in Roma Than Greek Children and Adolescents

STUDY DESIGN

Serial screening of Roma children for idiopathic scoliosis.

OBJECTIVE

To confirm or reject the observation that the prevalence of scoliosis is reduced in the Roma population and possibly to explain it.

MATERIALS AND METHODS

The authors conducted serial screening for idiopathic scoliosis of 1,034 indigenous Roma children (542 boys and 492 girls), aged 4-18 years (857 children were aged 8-18 years) from 1997 to 2011. Age, height, weight, body mass index, years of schooling, and menarche for girls were recorded. Children were clinically examined for body asymmetries and a standing posteroanterior spinal radiograph was obtained in selected cases.

RESULTS

Sixty Roma children (6%) had clinical humps. Single humps, according to location, were mostly benign and not related to progressive scoliotic curves. In children with right thoracic humps a left lumbar component could be overlooked. Of 60 children, only 4 (3 girls and 1 boy) with right thoracic and left lumbar or thoracolumbar humps had true progressive scoliotic curves with greater than 10° Cobb angle (prevalence rate, 0.35%). This is 5 times less than the rate of 1.5% in Greek children. One of these 4 children was young and had possible congenital scoliosis; the other 3 were early adolescents.

CONCLUSIONS

A substantial difference in the prevalence of scoliosis between Roma and Greek children was documented. The usual percentage of adolescent scoliosis found in the Greek population (approximately 15-17 cases/1,000 children) was not seen in this sample of Roma children.