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 3.2% 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.