Artificial Vertebral Body Versus Titanium Mesh Cage for Single-Level Anterior Cervical Corpectomy and Fusion (ACCF): A Propensity Score Matching Analysis of Fusion, Implant Subsidence and Clinical Outcomes

Background 3D printed artificial vertebral bodies (AVBs) have emerged as a viable alternative to traditional titanium mesh cages (TMCs) for spinal reconstruction following ACCF. However, existing comparative studies evaluating mid-term clinical and radiographic outcomes - particularly those incorporating quantitative assessments of fusion efficacy - remain inconclusive. This study aims to compare clinical and radiological outcomes between AVB and TMC in patients undergoing single-level ACCF with matched baseline characteristics. Methods Patients who underwent single-level ACCF for degenerative cervical myelopathy (DCM) between January 2012 and December 2022, with a minimum of 2-year clinical and radiological follow-up, were included. Patients were grouped by implant type (AVB or TMC), and propensity score matching (PSM) was used to balance baseline characteristics. Outcomes were assessed at 3 months and final follow-up (more than 2 years). Radiological assessments comprised: (1) fusion status evaluated via extra graft bridging bone (ExGBB) on computed tomography (CT) scans and interspinous motion (ISM) parameters; (2) implant subsidence; and (3) cervical alignment changes. Clinical parameters included neck pain (using Visual Analogue Scale), modified Japanese Association (mJOA) score and Neck Disability Index (NDI). Results A total of 93 patients were included (49 in AVB and 44 in TMC group). After 1:1 PSM, 36 patients were matched for each group, and intergroup comparisons revealed comparable baseline conditions. At 3 months, the AVB group exhibited significantly smaller ISM distance (p = 0.019) and less subsidence (p = 0.027) compared to the TMC group. The final follow-up duration was 3.57 ± 1.58 years. At final follow-up, no significant differences in subsidence and cervical alignment maintenance were observed. Furthermore, in fusion status, no significant intergroup differences were found, either in ExGBB or ISM criteria. The two group showed similar neurological recovery and pain alleviation, while the AVB group demonstrated significantly greater 3-month (p = 0.002) and final follow-up (p = 0.011) NDI improvement. However, no significant differences were observed in the proportion of patients achieving the minimal clinically important difference (MCID) for NDI. Conclusions The usage of AVB and TMC resulted in similar fusion outcomes, subsidence and neurological recovery at mid-term. However, AVB might have superior short-term implant stability with less 3-month subsidence and better fusion.