Authors’ reply to the letter to the editor of P.M. Foye et al. concerning “CT Morphology and Morphometry of the normal adult coccyx” by Woon JT et al. (2013); Eur Spine J 22(4):863–870

Abstract

We thank the correspondents for their kind comments about our recently published study [1]. We agree with their statement that certain bony features present in normal adults could nevertheless be a potential source of pain in some patients with coccydynia. Indeed, this prompted us to complete a further study comparing the bony morphology of the coccyx in normal adults with that in patients with coccydynia, which we have recently published [2]. In this study, women with coccydynia were found to have a significantly higher frequency of bony spicule formation than normal women (44 vs. 19 %; P < 0.01). Affected women also had a significantly more ventrally curved coccyx and a lower prevalence of sacrococcygeal joint fusion. These data will hopefully provide a better understanding of the static bony changes present on cross-sectional imaging in patients with coccydynia.