INTRODUCTION: Many surgeons currently prefer to use transforaminal lumbar interbody fusion (TLIF) with unilateral pedicle screw (PS) fixation to treat degenerative spondylolisthesis, and have reported good clinical results. To date, no study has been performed to examine whether unilateral PS fixation improves surgical outcomes as well as bilateral PS fixation. A prospective randomized controlled study was conducted to compare surgical outcomes of TLIF using unilateral PS fixation with those of bilateral PS fixation.
METHODS: Fifty degenerative spondylolisthesis patients undergoing one‐level TLIF were randomly assigned to receive either unilateral PS fixation (unilateral group) or bilateral PS fixation (bilateral group). Forty‐seven patients followed‐up for more than two years were included in this study. Parameters compared between the two groups were severity of intermittent claudication [IMC, 0‐3: JOA score], pre‐ and postoperative visual analogue scales (VAS, 0‐10: back‐pain, lower‐extremity pain, and lower‐extremity numbness), and post‐operative disability scores for lumbar spinal disorders (JOABPEQ).
RESULTS: Intermittent claudication improved significantly after both surgeries with no significant difference observed between the two groups. Pre‐operative VAS (unilateral, bilateral) for back pain (5.0, 5.2) and lower‐extremity pain (5.9, 6.4) showed no significant difference; however, the post‐operative VAS was significantly worse in the unilateral group for back pain (3.4, 1.5) and lower extremity pain (3.7, 1.3). The unilateral group also showed significantly less improvement of VAS for lower extremity numbness: pre‐op (5.6, 7.3), post‐op (3.9, 2.9). There were no significant differences between the two groups in the post‐operative scores for all five items of the JOABPEQ.
DISCUSSION: Compared to bilateral PS fixation, unilateral PS fixation resulted in less improvement of back‐pain, lower‐extremity pain, and lower‐extremity numbness.