Preventive Effect of Artificial Ligamentous Stabilization on the Upper Adjacent Segment Impairment Following Posterior Lumbar Interbody Fusion

Study Design. A retrospective, comparative study. Objective. To assess the effects of soft stabilization with artificial ligamentous bands placed on the upper segment adjacent to posterior lumbar interbody fusion (PLIF) for prevention of transition syndrome compared with patients who underwent PLIF without soft stabilization. Summary of Background Data. Spine fusion increases mechanical stress and can cause other spinal problems adjacent to the fusion level. Soft stabilization using artificial ligamentous bands has been reported to decrease the flexion instability and this iatrogenic problems. There is no report concerning the effect of soft stabilization to transition syndrome following PLIF. Methods. In 225 patients undergoing L4/5 PLIF, 70 consecutive patients who were treated concomitantly with decompression of L3/4 with minimum 2-year follow-up were included. Thirty-five patients underwent soft stabilization of L3/4 (soft stabilization [S] group) with natural neutral concept rods, and 35 patients did not (decompression [D] group). Radiographic changes in the disc height, vertebral slip, intervertebral angle, range of motion, lumbar lordosis, and L3 tilt angle were measured. On magnetic resonance imaging (MRI), postoperative progression of the disc degeneration and spinal canal stenosis were evaluated. Results. In the S group, significant posterior intervertebral expansion on radiograph was less advanced at the final follow-up (P < 0.005). MRI images demonstrated less significant aggravation of disc degeneration (P < 0.001) and progression of adjacent stenosis (P < 0.01), at L3/4 in the S group. Adjacent intervertebral changes on MRI occurred relatively early after surgery, suggesting that changes were due to transition syndrome, but not age-related changes. Conclusion. These results demonstrated an effect of soft stabilization for the prevention of transition syndrome in lumbar spine fusion. Although the postoperative follow-up periods in this study were not sufficiently long to reach a definitive conclusion, intervertebral breakdown adjacent to the rigid spine fusion could be diminished by the application of soft stabilization.