A comparison of long-term outcomes of nanohydroxyapatite/polyamide-66 cage and titanium mesh cage in anterior cervical corpectomy and fusion: A clinical follow-up study of least 8 years

Objectives: The nanohydroxyapatite/polyamide-66 (n-HA/PA66) cage is a novel biomimetic nonmetal cage device that is now used in some medical centers, while the titanium mesh cage (TMC) is a typical metal cage device that has been widely used for decades. This study was performed to compare the long-term outcomes of these two different cages in patients undergoing anterior cervical corpectomy. Patients and methods: This retrospective study involved 107 patients who underwent single-level anterior corpectomy using either a TMC (n = 52) or an n-HA/PA66 cage (n = 55) for treatment of cervical degenerative disease with a minimum follow-up of 8 years. Their radiographic data (cage subsidence, fusion status, segmental sagittal alignment, and cervical spine degeneration) and clinical data [visual analog scale (VAS) and Japanese Orthopedic Association (JOA) scores] were evaluated preoperatively, postoperatively, and at the final follow-up. Results: The mean duration of follow-up was 103.6 +/- 6.3 months in the n-HA/PA66 group and 102.4 +/- 4.6 months in the TMC group. The n-HA/PA66 group and the TMC group had similar final fusion rates (97% vs. 94%, respectively). The final n-HA/PA66 cage subsidence was 2.4 +/- 1.0 mm with 18.2% subsidence of > 3 mm, which was significantly lower than the respective 3.0 +/- 0.7 mm and 40.4% for the TMC (p < 0.01). The n-HA/PA66 group also had better JOA scores than the TMC group (p < 0.01). No significant difference in the segmental sagittal alignment, cervical lordosis, or VAS score was observed between the two groups (p = 0.18, 0.42, and 0.17, respectively). Conclusions: The n-HA/PA66 cage is associated with excellent radiographic fusion, lower subsidence and better clinical outcomes than the TMC within 8 years after single-level anterior cervical corpectomy. With the addtional benefit of radiolucency, the n-HA/PA66 cage could be superior to the TMC in anterior cervical construction.