During forward bending (Adam's test), spine shifts to either side and changes its pattern. Such a dynamic 3D change is difficult to be quantified with conventional X-ray imaging techniques due to exposure to ionized irradiation. For this reason, 3D ultrasound imaging was developed. Using a handheld ultrasound probe, we aimed to investigate measurement accuracy, detect dynamic changes during forward-bending, classify the curvatures and compare differences. Material and method: A total of 72 AIS patients, age: 15.3 ± 1.9 yrs, BMI: 18.0 ± 2.4 kg/m2were recruited. All patients received standing AP X-ray radiograph (EOS) for comparison with 3D ultrasound scanning (Scolioscan). Trunk rotation (ATR) was measured by scoliometer. Scanning was performed between L5 and C7 by a handheld probe in upright-sitting and forward-bending positions. 3D-image was reconstructed based on 2D-images, and spinal processes were used to form a spinal process angle (SPA), representing coronal plane changes. Results: Reliability of SPA measurement was found very good (ICC: 0.86) in both sitting and forward-bending positions. The SPA significantly decreased from 15.1 ± 6.3° to 11.8 ± 6.9°(P < 0.001) by forward-bending. Very low correlation was found between SPA change and ATR (r = 0.064, P = 0.62) and Cobb's angle (r = 0.17, P = 0.09). The C-shape curve remained C (n = 20), while S-shape curve changed into C (n = 17) and rest of patients (n = 35) retained S-shape during forward-bending. Conclusion: Using ultrasound to construct a 3D image of the spine revealed significant changes in the coronal plane during forward-bending, where the biggest amount of flexibility, presented by a difference between two positions, happened in S-shape curvature. C-shape displayed the smallest change. This ultrasound technique, as a reliable measurement, is expected to facilitate understanding of the functionality and/or flexibility of the scoliotic curve. Hence ultrasound provided frequent scanning can potentially bypass X-ray imaging, help to follow the progress with frequent scanning and redesign the treatment accordingly.
- Ultrasound imaging
ASJC Scopus subject areas
- Orthopedics and Sports Medicine