Long-term effectiveness of stand-alone anchored spacer in multilevel anterior cervical discectomy and fusion compared with cage-plate system: a systematic review and meta-analysis.

Objective: For anterior cervical discectomy and fusion (ACDF), stand-alone anchored spacers (SAAS) and cage-plate system (CPS) are currently employed. However, controversy remains over the effectiveness and security of these two apparatuses in multilevel ACDF. The aim of this study was to demonstrate the global long-term effectiveness and safety of SAAS versus CPS with multilevel ACDF.

Methods: We conducted a systematic review of studies comparing SAAS with CPS for multilevel ACDF using four electronic databases. Data from this meta-analysis were analyzed with Stata MP 17.0.

Results: A total of nine trials comprising 584 patients were selected for inclusion. SAAS significantly reduced operative time, intraoperative bleeding and the incidence of postoperative dysphagia compared with CPS. The SAAS group exhibited significantly smaller cervical sagittal angle (CSA) and fusion segmental height (FSH) compared to CPS group. At final follow-up, the rate of cage sinking was higher in SAAS group compared to CPS group. At the endpoint, there was no difference in JOA score, NDI score, fusion rate or the incidence of adjacent segment degeneration (ASD).

Conclusions: SAAS provided comparable long-term effectiveness and safeness for multilevel ACDF regarding JOA scores, NDI scores, fusion rates and ASD rates at endpoint compared to CPS. In comparison to CPS, SAAS demonstrated significant advancement in the reduction of operative time, intraoperative blood loss and the incidence of postoperative dysphagia. As a consequence, SAAS appeared more desirable than CPS among people who needed multilevel ACDF. Yet in long-term observation, SAAS was inferior to CPS in maintaining CSA and FSH and in preventing cage descent. However, whether or not radiographic abnormality has an impact on clinical presentation awaits confirmation from research with more longitudinal follow-up.