Comparative observational study of surgical outcomes of lumbar foraminal stenosis using minimally invasive microsurgical extraforaminal decompression alone versus posterior lumbar interbody fusion: a prospective cohort study

There is no comparative study regarding surgical outcomes between microsurgical extraforaminal decompression (MeFD) and posterior lumbar interbody fusion (PLIF) for the treatment of lumbar foraminal stenosis (LFS). Therefore, the purpose of this study was to compare the surgical outcomes of LFS using two different techniques: MeFD alone or PLIF. For the purposes of this study, a prospectively collected observational cohort study was conducted. Fifty-five patients diagnosed with LFS who were scheduled to undergo spinal surgery were included in this study. According to the chosen surgical technique, patients were assigned to either the MeFD group (n = 25) or the PLIF group (n = 30). The primary outcome was Oswestry Disability Index (ODI) score at 1 year after surgery. The baseline patient characteristics and preoperative ODI score, visual analog scale (VAS) scores for back and leg pain, and Short Form-36 score were not significantly different between the two groups. At 12 months postoperative, the mean ODI score in the MeFD and PLIF groups was 25.68 ± 14.49 and 27.20 ± 12.56, respectively, and the 95 % confidence interval (−9.76–6.73) was within the predetermined margin of equivalence. The overall ODI score and VAS scores for back and leg pain did not differ significantly over the follow-up assessment time between the two groups. However, the ODI score and VAS scores for back and leg pain improved significantly over time after surgery in both groups. In the MeFD group, revision surgery was required in three patients (12 %). This study demonstrated that MeFD alone and PLIF have equivalent outcomes regarding improvement in disability at 1 year after surgery. However, the higher rate of revision surgery in the MeFD group should emphasize the technically optimal amount of decompression.