Could self-locking stand-alone cage reduce adjacent-level ossification development after aneterior cervical discectomy and fusion?

Numerous studies have shown that cervical arthrodesis is associated with the adjacent-segment pathology (ASP), such as adjacent-level ossification development (ALOD). However, it still remains largely unclear whether the self-locking stand-alone implant system can reduce the incidence of ALOD. In the present study, we prospectively recruited 120 patients with cervical degenerative disc disease (CDDD) who were treated by anterior cervical discectomy and fusion (ACDF). These patients were randomly and evenly divided into the ROI-C group and plate group. Clinical and radiologic follow-up was performed at 3, 6, 12, 24 and 36 months after surgery. Clinical evaluation included preoperative and postoperative assessments of Japanese Orthopaedic Association (JOA) score and Neck Disability Index (NDI) score. The presence and severity of ALOD, as well as the C2-7 Cobb angle, were assessed on the lateral cervical films during follow-up. There were no significant differences in JOA and NDI scores at each time point during the follow-up period between the two groups. ALOD occurred in 8.8% of 58 patients and 6.7% of 104 levels in the cage group. Moreover, ALOD occurred in 20.1% of 57 patients and 17.8% of 101 levels in the plate group. The ALOD was more serious in the plate group compared with the cage group. The C2-7 Cobb angle was significantly improved compared with that before the operation and could be maintained during the follow-up in both groups. The self-locking stand-alone cage was efficacious for ACDF, and it could reduce the incidence of ALOD compared with anterior plate and cage.