Does Facet Tropism Influence the Clinical Outcomes of Posterior Lumbar Interbody Fusion for Degenerative Lumbar Spondylolisthesis?

Introduction: Patients with degenerative lumbar spondylolisthesis (DLS) have poor postoperative satisfaction, which may be related to the anatomical structure, in which facet joints may be an important link. This study was to investigate the influence of facet tropism (FT) on spinal parameters and clinical symptoms of DLS after posterior lumbar intervertebral fusion (PLIF).

Methods: A total of 150 patients with DLS who received PLIF surgery were retrospectively analyzed and divided into non-facet tropism (NFT) group and FT group according to bilateral facet joint angle (FJA) difference of more than 10°. Changes in clinical data before and after surgery were compared between the two groups. Correlation analysis was performed between imaging parameter changes and symptom score changes. Groups were divided according to different segments of preoperative FT to compare imaging parameters and symptom score changes between each group and the control group.

Results: 62 patients completed the follow-up with an average follow-up time of 22.60 months. The lumbar range of motion (ROM) in FT was lower than that in NFT, and the other preoperative clinical data were similar. The imaging parameters and clinical symptom scores for both groups improved after PLIF compared to their preoperative levels. The ROM in FT was lower than those in NFT. The symptom scores of the two groups were improved equally, but the VAS score and ODI score at follow-up in FT were significantly higher than those in NFT. Changes in imaging parameters and range of motion were significantly correlated with improvements in VAS and ODI in both groups.

Conclusion : PLIF can improve the symptoms of DLS and restore the physiological curvature of the lumbar spine, but the ROM is obviously limited after operation. Facet tropism can weaken the shape correction of the lumbar spine, which is an important reason for the poor efficacy of PLIF surgery. PLIF may not be an appropriate treatment for patients with FT. FT should be considered before operation to make a more appropriate surgical plan.