Comparison of two ultrasound methods from Scolioscan^® for measuring spinal curvature: spinous processes (SP) versus...

The current gold standard in scoliosis diagnostics remains the measurement of the curvature angle using X-ray imaging. Several studies have already shown that children and adolescents with scoliosis suffer from health consequences due to cumulative radiation exposure from frequent radiological follow-ups. Ultrasound diagnostics offers a radiation-free alternative for imaging scoliosis. Various studies have already shown good reliability and validity of different ultrasound devices and various ultrasound methods for measuring the curvature angle in patients with scoliosis. The aim of this study - investigating secondary hypotheses of our main study on "Assessment of the Efficacy of physiotherapeutic scoliosis-specific exercises (PSSE) for Scoliosis through Ultrasound-Based Imaging Techniques" - was to compare two different ultrasound diagnostic methods for scoliosis with the gold standard, X-ray, and to assess their validity and reliability. The curvature angle can be determined using ultrasound based on either the spinous processes (SP) or the transverse processes (TP). The goal was to find out whether one of the two methods is more valid and should therefore be preferred in clinical practice.

Seventy-one patients with AIS (= adolescent idiopathic scoliosis) (60 females, 11 males, average age 14,79) underwent both an anterior-posterior X-ray of and an ultrasound measurement of the spine by one or two different examiners. The Cobb angle was determined in the X-rays and the ultrasound data were automatically measured by the Scolioscan^® software using both methods SP and TP.

The SP ultrasound method results are in the range of moderate to excellent reliability with ICC values between 0,702 and 0,900. For the TP ultrasound method results show good reliability with ICC values between 0,888 and 0,893. The different Bland Altman Plot diagrams indicate good agreement between both ultrasound measurements and the X-ray. The scatterplot diagrams also show a very good correlation of the values.

It was shown that both the ultrasound methods TP and SP are valid. Particularly for patients requiring frequent follow-up examinations, ultrasound should be used as a diagnostic tool. The TP method is especially in the lumbar region more accurate, has smaller spread in the confidence intervals, is easier to handle and easier for patients to understand and should therefore be preferred over the SP method.