Quasi-automatic early detection of progressive idiopathic scoliosis from biplanar radiography: a preliminary validation
To validate the predictive power and reliability of a novel quasi-automatic method to calculate the severity index of adolescent idiopathic scoliosis (AIS).
Fifty-five AIS patients were prospectively included (age 10–15, Cobb 16° ± 4°). Patients underwent low-dose biplanar X-rays, and a novel fast method for 3D reconstruction of the spine was performed. They were followed until skeletal maturity (stable patients) or brace prescription (progressive patients). The severity index was calculated at the first examination, based on 3D parameters of the scoliotic curve, and it was compared with the patient’s final outcome (progressive or stable). Three operators have repeated the 3D reconstruction twice for a subset of 30 patients to assess reproducibility (through Cohen’s kappa and intra-class correlation coefficient).
Eighty-five percentage of the patients were correctly classified as stable or progressive by the severity index, with a sensitivity of 92% and specificity of 74%. Substantial intra-operator agreement and good inter-operator agreement were observed, with 80% of the progressive patients correctly detected at the first examination. The novel severity index assessment took less than 4 min of operator time.
The fast and semiautomatic method for 3D reconstruction developed in this work allowed for a fast and reliable calculation of the severity index. The method is fast and user friendly. Once extensively validated, this severity index could allow very early initiation of conservative treatment for progressive patients, thus increasing treatment efficacy and therefore reducing the need for corrective surgery.
KeywordsAdolescent idiopathic scoliosis 3D reconstruction Reliability Feature extraction Severity index
The authors are grateful to the ParisTech BiomecAM chair program on subject-specific musculoskeletal modeling (with the support of ParisTech and Yves Cotrel Foundations, Société Générale, Proteor and Covea).
Compliance with ethical standards
Conflict of interest
Wafa Skalli holds patents related to the EOS system and associated 3D reconstruction methods, with no personal financial benefit (royalties rewarded for research and education). Raphael Vialle received consulting fees from EOS Imaging unrelated to this study.
- 3.Negrini S, Minozzi S, Bettany-Saltikov J, et al (2015) Braces for idiopathic scoliosis in adolescents. Cochrane database Syst Rev 6:CD006850. https://doi.org/10.1002/14651858.CD006850.pub3
- 11.Perdriolle R, Vidal J (1981) A study of scoliotic curve. The importance of extension and vertebral rotation (author’s transl). Rev Chir Orthop Reparatrice Appar Mot 67:25–34Google Scholar
- 12.Dubousset J (1994) Three-dimensional analysis of the scoliotic deformity. In: Weinstein SL (ed) The pediatric spine: principles and practice. Raven Press Ltd., New York, pp 479–496Google Scholar
- 15.Danielsson AJ, Hasserius R, Ohlin A, Nachemson AL (2007) A prospective study of brace treatment versus observation alone in adolescent idiopathic scoliosis: a follow-up mean of 16 years after maturity. Spine (Phila Pa 1976) 32:2198–2207. https://doi.org/10.1097/BRS.0b013e31814b851f CrossRefGoogle Scholar
- 22.Ebrahimi S, Angelini E, Gajny L, Skalli W (2016) Lumbar spine posterior corner detection in X-rays using Haar-based features. In: IEEE 13th international symposium on biomedical imaging (ISBI), pp 180–183Google Scholar