The residual exposed endplate ratio is predictive of posterior heterotopic ossification after cervical Bryan disc arthroplasty

• Published in: Journal of clinical neuroscience 2023-08, Vol.114, p.97-103
• Main Authors: Huang, Chih-Wei, Tsou, Hsi-Kai, Chen, Wen-Hsien, Tsai, Jen-Chieh, Chung, Kai-Chen, Lin, Ruei-Hong, Chen, Tse-Yu, Tzeng, Chung-Yuh
• Format: Article
• Language: English
• Subjects: Adult; Arthroplasty - adverse effects; Bryan CDA; Cervical disc arthroplasty; Cervical Vertebrae - diagnostic imaging; Cervical Vertebrae - surgery; Dysfunction; Heterotopic ossification; Humans; Intervertebral Disc - diagnostic imaging; Intervertebral Disc - surgery; Intervertebral Disc Degeneration - surgery; McAfee classification; Ossification, Heterotopic - diagnostic imaging; Ossification, Heterotopic - etiology; Postoperative Complications - diagnostic imaging; Postoperative Complications - etiology; Postoperative Complications - surgery; Residual exposed endplate; Retrospective Studies; Treatment Outcome
• ISSN: 0967-5868; 1532-2653
• DOI: 10.1016/j.jocn.2023.06.005

•Heterotopic ossification following cervical total disc replacement is an emerging issue in cervical spine surgery.•We analyzed 384 surgical levels of cervical total disc replacement with the same implant by the same surgeon.•This retrospective study investigated the relationship between the REE ratio and posterior HO formation after Bryan CDA.•Residual endplate ratio highly correlated with the development of postoperative HO. Heterotopic ossification (HO), a major cause of dysfunction after disc arthroplasty (CDA). The aim of this study was to determine the cut value of the residual exposed endplate (REE) ratio and to predict the development of posterior HO after Bryan CDA. This retrospective study investigated the relationship between the REE ratio and posterior HO formation after Bryan CDA. Consecutive adult patients who underwent 1- or 2-level Bryan CDA by a single neurosurgeon between 2006 and 2016 with at least two years follow-up were included. Postoperative radiographic analysis and measurement were performed to obtain the REE ratio and the HO grade. Of 249 patients with 384 surgical levels who underwent Bryan CDA during the study period, 114 (45.8 %) received 1-level CDA and 135 (54.2 %) received 2-level CDA. Lateral radiographs showed that 169 implants (44 %) had posterior HOs in all grades after two years or more of follow up and 14 implants (3.64 %) had severe HO (McAfee grades 3 and 4). In 329 implants (85.7 %), a comparison of radiographs to CT examination of HO grading showed a substantial relationship. Using area under the curve (AUC) analysis, a REE ratio >9 %, with 65.1 % sensitivity and 86.5 % specificity, was the cut point for posterior HO formation. REE is highly correlated with the development of postoperative posterior HO after Bryan CDA, regardless of the level of implantation. An undersized implant causing a REE ratio >9 % is a predictor of postoperative posterior HO formation after cervical Bryan CDA.