| Objective: This study aims to analyse the function of endplate on fusion and the cage subsidence by the patients after anterior cervical discectomy and fusion(ACDF).Furthermore,we explored risk factors for the cage subsidence and whether the cage subsidence had an effect on recovery so that providing the evidence for surgical decision-making.Methods: A total of 77 patients with ossification of posterior longitudinal ligament(OPLL)underwent one/two-level ACDF from January 2013 to December 2015.All patients in our Department were recommended to be reviewed at 6 weeks and 6 months after surgery and then annually in outpatient clinic.Meanwhile,clinical and radiological outcomes were assessed.The decrease of the interbody height at the final follow-up compared to that measured on the first postoperative day.Interbody height(IH)decrease in ? 2 mm,which was defined the implant subsidence.Intervertebral fusion was evaluated onthebasis of no motion across the fusion site and the presence of trabeculae between bone and implant in the X-rays.Multivariate logistic regression analysis identified the predictors for implant subsidence.Results: Comparison of two groups which included endplate removal group and endplate preservation group,the fusion rate(35.9%)and the change of IH(P=0.011)were significant differences at the first 6 weeks after surgery.Advanced age(OR=1.34,95% CI=1.04-1.24,P=0.004)and end-plate removed(OR=11.84,95% CI=2.91-48.28,P=0.001)and nonunion within 6 weeks after surgery(OR=22.67,95% CI=2.36-217.67,P=0.007)had good accuracy to predict implant subsidence.Conclusions: The endplate removal led to the cage subsidence in the early postoperative period.Advanced age,endplate removal and nonunion within 6 weeks after surgery were risk factors for implant subsidence.As the cage subsidence may trigger a few complications,even the failure of hardware,a better understanding about the significance of risk factors can help surgeons make more reasonable surgical scheme. |
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