Are there advantages in cervical intrafacetal fusion (cIFF) with minimal posterolateral fusion (PLF) compared to conventional PLF in posterior cervical fusion?

OBJECTIVE: We propose that cervical intrafacetal fusion (cIFF) using bone chip insertion into the facetal joint space additional to minimal PLF is a supplementary fusion method to conventional posterolateral fusion (PLF).

METHODS: Patients who underwent posterior cervical fixation accompanied by cIFF with minimal PLF or conventional PLF for cervical myelopathy from 2012 to 2023 were investigated retrospectively. Radiological parameters including Cobb's angles and C2-7 sagittal vertical axis (SVA) were compared between two groups. In cIFF with minimal PLF group, cIFF location and PLF location were carefully divided, and the fusion rates of each location were analyzed by CT scan.

RESULTS: Among enrolled 46 patients, 31 patients were in cIFF group, 15 in PLF group. The postoperative change of Cobb's angle in 1-year follow-up in cIFF with minimal PLF group and conventional PLF group were 0.1˚ ± 4.0 and -9.7˚ ± 8.4 respectively which was statistically lower in cIFF with minimal PLF group (p=0.022). Regarding the fusion rate in cIFF with minimal PLF group in postoperative 6 months, the rates was achieved in 267 facets (98.1%) in cIFF location, and 244 facets (89.7%) in PLF location (p<0.001).

CONCLUSION: Postoperative sagittal alignment was more preserved in cIFF with minimal PLF group compared with conventional PLF group. Additionally, in cIFF with minimal PLF group, the bone fusion rate of cIFF location was higher than PLF location. Considering the concerns of bone chip migration onto the spinal cord and relatively low fusion rate in PLF method, applying cIFF method using minimized PLF might be a beneficial alternative for posterior cervical decompression and fixation.