Modified Facet Joint Fusion for Lumbar Degenerative Disease: Case Series of a Fusion Technique, Clinical Outcomes, and Fusion Rate in 491 Patients

BACKGROUND: Controversy still exists regarding the optimal fusion technique for the treatment of unstable lumbar spondylolisthesis. OBJECTIVE: To evaluate the safety and efficacy of modified facet joint fusion (MFF). METHODS: A total of 491 patients with unstable lumbar spondylolisthesis who underwent MFF were retrospectively reviewed. Computed tomography was used to evaluate the fusion rate of MFF at 6- and 12-mo follow-up postoperatively. Clinical outcomes included visual analog scale pain scores for low back pain (VAS-LBP) and leg pain (VAS-LP), Japanese Orthopedic Association scores (JOA), and Oswestry Disability Index (ODI), all of which were obtained preoperatively and postoperatively at 1-, 3-, 6-, and 12-mo follow-up times. The clinical outcomes were determined to be excellent, good, fair, or poor according to the MacNab classification at the last follow-up time. RESULTS: Of the 491 patients, the fusion rates at the 6-mo and 1-yr follow-up were 56.8% and 96.1%, respectively. Between baseline and 1-yr follow-up time, VAS-LP and VAS-LBP improved from 5.6 +/- 0.9 to 0.4 +/- 0.5 and 5.1 +/- 1.2 to 1.5 +/- 0.9, respectively (P < .001). JOA improved from 9.0 +/- 2.0 to 27.7 +/- 1.0, and ODI decreased from 64.0 +/- 2.0 to 19 +/- 1.0 (P < .001). At the final evaluation, 93.6% patients showed excellent or good results, and 32% showed fair results. There were no MFF technique-related complications. CONCLUSION: MFF technique achieved satisfactory clinical outcomes and fusion rate and appears to be a promising alternative fusion technique for the treatment of unstable lumbar spondylolisthesis.