Aims To clarify the asymmetrical ossification of the epiphyseal ring between the convex and concave sides in patients with adolescent idiopathic scoliosis (AIS).
Patients and Methods A total of 29 female patients (mean age, 14.4 years; 11 to 18) who underwent corrective surgery for AIS (Lenke type 1 or 2) were included in our study. In all, 349 vertebrae including 68 apical vertebrae and 87 end vertebrae in the main thoracic (MT) curve and thoracolumbar/lumbar (TL/L) curve were analysed. Coronal sections (anterior, middle and posterior) of the vertebral bodies were reconstructed from pre-operative CT scans (320-row detector; slice thickness, 0.5 mm) and the appearances of the ossification centre in the epiphyseal ring at four corners were evaluated in three groups; all vertebrae excluding end vertebrae, apical vertebrae and end vertebrae. The appearance rates of the ossification centre at the concave and convex sides were calculated and compared.
Results The appearance rates of the ossification centres in all vertebrae excluding end vertebrae and apical vertebrae were significantly lower on the concave side than on the convex side in both MT and TL/L curves irrespective of curve flexibility. There was no significant difference in the rate of appearance of the ossification centres on the concave or convex sides in end vertebrae.
Conclusion The asymmetric bony growth of vertebral body came into existence at both structural and non-structural curves, and was more apparent around the apical vertebrae. Evaluation of the ossification centre in the epiphyseal ring could be a measure of the effectiveness of brace treatment.
Take home message: The ossification of the epiphyseal ring in patients with AIS was delayed or absent on the concave side particularly around the apical vertebrae.
Cite this article: Bone Joint J 2016;98-B:666–71.
T. Makino: Initial idea and design of the study, Data collection and analysis, Paper writing.
T. Kaito: Assistance with writing the paper, Review of the manuscript and feedback.
Y. Sakai: Assistance with writing the paper, Review of the manuscript and feedback.
M. Kashii: Assistance with writing the paper, Review of the manuscript and feedback.
H. Yoshikawa: Review of the manuscript and feedback.
This work was supported by JSPS Grant-in-Aid for Young Scientists (B) Grant Number 15K19994.
No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.
This article was primary edited by S. P. F. Hughes and first proof edited by G. Scott.
Supplementary material. A table showing patient demographic data and a graph showing differences of the appearance rates between the convex and concave sides is available alongside the online version of this article at www.bjj.boneandjoint.org.uk.
- Received August 20, 2015.
- Accepted January 18, 2016.
- ©2016 The British Editorial Society of Bone & Joint Surgery