Comparison of Titanium Mesh Cage, Nano-Hydroxyapatite/Polyamide Cage, and Three-Dimensional-Printed Vertebral Body for Anterior Cervical Corpectomy and Fusion

Study design: A prospective nonrandomized controlled study.

Objective: To compare the clinical and radiographic outcomes of anterior cervical corpectomy and fusion (ACCF) using titanium mesh cages (TMCs), nano-hydroxyapatite/polyamide 66 (n-HA/PA66) cages, and three-dimensional-printed vertebral bodies (3d-VBs).

Background: Postoperative subsidence of TMCs in ACCF has been widely reported. Newer implants such as n-HA/PA66 cages and 3d-VBs using biocompatible titanium alloy powder (Ti6Al4V) have been introduced to address this issue, but their outcomes remain controversial.

Patients and methods: We enrolled 60 patients undergoing ACCF using TMCs, n-HA/PA66 cages, or 3d-VBs from January 2020 to November 2021. For each group, there were 20 patients. Follow-up was conducted for a minimum of 2 years. Clinical outcomes, including Japanese Orthopedic Association (JOA) scores, Neck Disability Index, and Visual Analog Scale scores, and radiographic outcomes, including function of spinal unit (FSU) height, fusion rate, and cervical alignment, were collected preoperatively and at each follow-up. A loss of FSU height ≥3mm was deemed implant subsidence. One-way analysis of variance was used for comparisons of mean values at different time points within the same group, with pairwise comparisons performed using the least significance difference method. The Mann-Whitney test was used for comparisons between groups. Categorical data such as sex, smoking status, implant subsidence, and pathology level were analyzed using the χ 2 test.

Results: Postoperative FSU height loss at 2 years differed significantly among the TMC, n-HA/PA66, and 3d-VB groups, measuring 3.07 ± 1.25mm, 2.11 ± 0.73mm, and 1.46 ± 0.71mm, respectively ( P < 0.001). The rates of implant subsidence were 45%, 20%, and 10%, respectively ( P = 0.031). All patients obtained solid fusion at a 2-year follow-up. We observed statistically significant differences in Visual Analog Scale and JOA scores at 3 months postoperatively, and JOA scores at 2 years postoperatively among the 3 groups. At a 2-year follow-up, the n-HA/PA66 and the 3d-VBs groups exhibited less FSU height loss, lower subsidence rates, and demonstrated better cervical lordosis than the TMC group. No severe postoperative complications were observed in any of the patients, and no patient required reoperation.

Conclusion: At a 2-year follow-up after ACCF, the n-HA/PA66 and the 3d-VBs groups exhibited less FSU height loss, lower subsidence rates, and demonstrated better cervical lordosis than the TMC group. Longer-term observation of implant subsidence in ACCF using TMC, n-HA/PA66, and 3d-VB is necessary.

Level of evidence: Level III-therapeutic.