The purpose of this study was to evaluate the clinical outcome of posterior lumber interbody fusion (PLIF) with the interbody fusion cage for L5/S1. PLIF was performed on 18 patients consisting of 12 males and 6 females. 8 were diagnosed as disc degeneration, 7 as spondylolisthesis, 3 as spondylolytic spondylolisthesis. The average patients age was 38.2 years. The mean JOA score improved to 25.3 on the last follow-up from the preoperative score of 14.2. Posterior elements were preserved as much as possible, and two cages were then inserted into both sides.
Low back pain and leg pain recurred in all patients. No breakage, displacement, backout of cage, progress of slipping, nor sinking was observed. In all cases, the interbody height was enlarged. Four cases showed clear zones less than 1mm around the cages. No motion was seen at the fusion level in all cases on dynamic radiographs.
We believe that PLIF with interbody fusion cage for L5/S1 is useful for cases with diminished disc space.