Background:

Clinical outcome of indirect decompression for a revision surgery, at the same level of a previous lumbar decompression (LD), has not been reported. The purpose of this study was to investigate the efficacy of oblique lateral interbody fusion (OLIF) in revision surgery after decompression for degenerative lumbar spinal disease.

Methods:

We included 34 patients who were preoperatively diagnosed with a recurrence of canal stenosis, foraminal stenosis, or intervertebral instability at the same level of a prior lumbar decompression. These patients underwent OLIF with supplemental pedicle screw fixation without additional posterior decompression. All patients completed a minimum 1-year follow-up. We compared the cross-sectional area (CSA) of the thecal sac on MRI as well as clinical outcome scores (Japanese Orthopaedic Association [JOA] score) preoperatively and at the final follow-up. Fusion status and disc height/angle were evaluated based on CT scans.

Results:

The CSA expanded from 136.4±57.9 mm² preoperatively to 194.1±58.6 mm² at the final follow-up (mean, 27.4 months; p<0.001). Clinical symptoms significantly improved (59.0% improvement rate of JOA score) at the average of a 17.1-month follow-up. The fusion rate was 93.0%. The disc height was restored (preoperative, 5.7 mm; postoperative, 8.3 mm; p<0.001), and foraminal stenosis significantly improved postoperatively. There were no major vascular/ureteral injuries.

Conclusions:

OLIF at the same level of a prior lumbar decompression provided a successful indirect decompressive effect, including expansion of the thecal sac, restoration of disc height, and subsequent improvement of foraminal stenosis. Specifically, this procedure can prevent incidental durotomy and nerve root injury, which may occur in conventional revision surgeries for direct posterior fusion.