Clinical Analysis Associated With Heterotopic Ossification Following Prestige Artificial Cervical Disc Replacement

Objective To analyze the effect of heterotopic ossification(HO)on the postoperative segmental range of motion(ROM)after Prestige artificial cervical disc replacement,and to explore the related factors leading to the formation of heterotopic ossification after artificial cervical disc replacement.Methods The records of 73 patients who had Prestige artificial cervical disc replacement from January 2014 to January 2018 in Department of Orthopedics,the First Affiliated Hospital of Chongqing Medical University were retrospectively reviewed.To evaluate cervical spine X-ray,sagittal alignment accuracy of prosthesis and the replacement segment ROM was measured in picture,and the occurrence of HO was defined by the McAfee's classification.The t test was used to analyze the influence between heterotopic ossification formation and replacement segment ROM.Ten clinical factors including age,gender,BMI,number of replacement segments,preoperative ligament ossification,the preoperative disc height ratio of the target level and its adjacent level,sagittal alignmentaccuracy,preoperative mobility of replacement segments,postoperative mobility of replacement segments,whether to use NSAIDs during perioperative period.The correlation between these nine clinical factors and the occurrence of postoperative HO was evaluated with logistic regression analysis.Results All 73 patients were followed up,among whom 24 patients had HO at the last follow-up(HO incidence: 32.9%).The surgical segmental ROM in the HO group was significantly lower than that in the non-HO group(P<0.001).Analysis showed that the posterior margin of the upper and lower prosthesis-endplate sagittal distance,the height of the intervertebral space,and the preoperative and postoperative surgical segmental ROM were all statistically significant for HO(P<0.05).However,multivariate logistic regression analysis showed that only the posterior margin of the upper prosthesis-endplate sagittal distance was related to HO(P=0.011),and ROC curve analysis revealed that HO was more likely to occur with a prosthesis-endplate sagittal distance error ?2.5mm.Conclusion HO after Prestige-LP cervical disc arthroplasty causes a reduction in the surgical segmental ROM,the occurrence of which is associated with the sagittal alignment accuracy of the prosthesis.HO was more likely to occur in patients with a prosthesis sagittal distance error ?2.5mm.