Effect of external cervical orthoses on clinical and radiological outcome of patients undergoing anterior cervical discectomy and fusion

Background: The current use of external cervical orthoses (ECO) after cervical discectomy is still based on a common practice than a solid scientific literature. The aim of this study is to evaluate the impact of ECO on radiological and functional outcomes in patients undergoing anterior cervical discectomy and fusion (ACDF). Methods: We compared two cohorts of consecutive patients who underwent ACDF with and without ECO after surgery. Thirty-six patients operated from January 2015 to June 2016 received an ECO whereas 36 patients, operated from July 2016 to December 2017, did not. Each patient underwent radiological and functional evaluation using plain x-ray at 1, 6, and 12 months after surgery and Neck Disability Index (NDI) at 2 weeks and 3, 6, and 12 months after surgery, respectively. Results: In the ECO group, 5 patients (13.9%) presented an incomplete fusion and 31 patients (86.1%) presented a complete fusion (CI 0.705–0.953). In the non-ECO group, 8 patients (22.2%) presented an incomplete fusion and 28 patients (77.8% [CI 0.608–0.899]) had a complete fusion, with no statistically significant differences between two groups. No statistically significant differences were also observed regarding the NDI neither at 2 weeks nor at 3-, 6-, and 12-month follow-up. At multivariate analysis, patients who underwent two-level ACDF showed a five-fold increased risk of worse NDI at 3-, 6-, 12-month (p = 0.003, CI 1.770–14.584) follow-up. Conclusions: We advise against the routine use of ECO after single- or two-level ACDF as we did not find out any significant statistical differences between the two groups.