Indirect decompression via oblique lateral interbody fusion for severe degenerative lumbar spinal stenosis: a comparative study with direct decompression transforaminal/posterior lumbar interbody fusion

Previous studies have shown that oblique lateral interbody fusion (OLIF) can improve neurological symptoms via "indirect decompression." However, data are lacking in terms of its benefits when compared with conventional transforaminal lumbar interbody fusion (TLIF) and/or posterior lumbar interbody fusion (PLIF) approach, especially in patients with severe central canal stenosis.

To investigate the clinical outcome of OLIF without posterior decompression versus conventional TLIF and/or PLIF in severe lumbar stenosis diagnosed on preoperative magnetic resonance imaging.

Retrospective comparative study.

Fifty-one patients who underwent OLIF and 41 patients who underwent conventional TLIF and/or PLIF.

Clinical outcome score by Japanese Orthopedic Association (JOA) score and radiographic outcomes (disc height and fusion rate on computed tomography scan).

We retrospectively reviewed 51 patients who underwent OLIF with supplemental percutaneous pedicle screws (55 levels; OLIF group) and 41 patients who underwent conventional TLIF and/or PLIF (47 levels; TPLIF group). The cross-sectional area of the thecal sac was measured preoperatively in OLIF and TPLIF groups, but postoperatively only in the OLIF group. All patients were diagnosed with severe stenosis based on Schizas classification (Grade C or D) on magnetic resonance imaging. We compared radiographic and clinical outcome scores (JOA score) between the 2 groups at 1 year of follow-up. The radiographic evaluation included the fusion status and disc height on computed tomography scan. Surgical data and perioperative complications were also investigated.

The baseline demographic data of the 2 groups were equivalent in preoperative diagnosis, JOA score, and disc height and/or angle. The cross-sectional area significantly increased postoperatively, which confirmed indirect decompressive effect in the OLIF group. The JOA score improved in both groups at the 1-year follow up (76.6% vs. 73.5% improvement rate in the OLIF and TPLIF groups, respectively). The fusion rate at the 1-year follow-up was higher in the OLIF group than in the TPLIF group (87.2% vs. 57.4%). The disc height restoration was also better in the OLIF group. The operative data demonstrated less estimated blood loss and operative time in the OLIF group.

OLIF and conventional TLIF and/or PLIF demonstrated comparable short-term clinical outcomes in the treatment of severe degenerative lumbar stenosis. However, the surgical and radiographic outcomes were better in the OLIF group. Surgeons should choose an appropriate approach on a case by case basis, recognizing the perioperative complications specific to each fusion procedure.