Comparison of surgical outcomes between oblique lateral interbody fusion (OLIF) and anterior lumbar interbody fusion (ALIF)

Objective: Although oblique lateral interbody fusion (OLIF) utilizes the similar approach in anterior lumbar interbody fusion (ALIF), OLIF is essentially a lateral lumbar interbody fusion (LLIF). Therefore, OLIF may have advantages in LLIF that the lateral cage can achieve greater restoration of the disc height and angle. We aimed to compared the surgical outcomes between OLIF and ALIF. Methods: This study involved 47 consecutive patients who underwent a single-level OLIF and 45 consecutive patients who underwent a single-level ALIF at L2-L5 levels. Radiological measurements included the changes of anterior/posterior disc height, coronal/sagittal disc angle, foramen cross-sectional area (CSA), cage position from the anterior margin of the lower vertebra, fusion rate, and cage subsidence using the serial radiographs and computed tomography preoperatively and at the postoperative 1-year follow-up. Clinical outcomes were assessed by visual analog scale (VAS) for back/leg pain, Oswestry disability index (ODI), and the occurrence of perioperative complications. Results: The baseline radiological and clinical parameters were similar between the OLIF and ALIF groups (all P > 0.05). At postoperative 1 year, the mean anterior disc height was higher in the OLIF group than the ALIF group (11.4 +/- 1.9 mm vs. 9.6 +/- 2.6 mm, P = 0.021). The mean sagittal disc angle was also greater in the OLIF group than the ALIF group (10.9 +/- 4.4 degrees vs. 8.9 +/- 5.8 degrees, P < 0.001). The mean cage position was 5.8 +/- 2.1 mm in the OLIF group and 8.7 +/- 2.3 mm in the ALIF group (P < 0.001). There was no difference in the postoperative changes of coronal disc angles, foramen CSA, fusion rate, cage subsidence, VAS for back/leg pain, ODI, and the occurrence of perioperative complications between the OLIF and ALIF groups (all P > 0.05). Conclusions: OLIF showed a greater increase in disc height and segmental lordosis than ALIF with comparable complications. OLIF is a meaningful progress from ALIF.