Modified facet joint fusion for multilevel lumbar spinal stenosis: a retrospective study of 135 consecutive patients.

Objective: To evaluate the safety and efficacy of modified facet joint fusion (MFF) for the treatment of multilevel (three-level or more) lumbar spinal stenosis (LSS).
Patients and Methods: In this retrospective study, 135 consecutive patients who underwent initial MFF for multilevel LSS were included. Clinical outcomes included fusion rate, change of visual analogue scale pain scores for low back pain (VAS-LBP) and leg pain (VAS-LP), Japanese Orthopedic Association scores (JOA), Oswestry Disability Index (ODI) and MacNab classification before and after MFF. The complications were also analyzed.
Results: The fusion rates were 46.7% (63/135) at 6-month and 89.6% (121/135) at 1-year. The mean VAS-LBP, VAS-LP, and ODI significantly decreased from 5.2 ± 0.6, 5.7 ± 0.8 and 65 ± 7.9 to 1.58 ± 0.4, 0.58 ± 0.3 and 20.8 ± 5.8, respectively (all p  < 0.001). The mean JOA markedly improved from 10.0 ± 1.3 to 26.1 ± 1.5 ( p  < 0.001). Excellent/good results of MacNab classification were achieved in 88.9% (120/135) of the patients. The overall rate of complications after MFF was 5.9%, including poor wound healing (2.2%), calf muscular venous thrombosis (0.74%), deep venous thrombosis (0.74%), superficial wound infection (1.48%), transient foot drop (0.74%). All the complications were transient and improved without prolonged hospital stay and sequelae.
Conclusion: MFF may be safe and efficient for multilevel LSS with high fusion rate and significant symptom relief, which is worthy of further study.