Posterior Lumbar Interbody Fusion Using an Unilateral Cage: A Prospective Study of Clinical Outcome and Stability

OBJECTIVE The purpose of this study was to evaluate the clinical and radiological results of instrumented posterior lumbar interbody fusion (PLIF) using an unilateral cage. METHODS Seventeen patients with unilateral radiculopathy who underwent bilateral percutaneous screw fixation with a single fusion cage inserted on the symptomatic side for treatment of focal degenerative lumbar spine disease were prospectively enrolled in this study. Their clinical results, radiological parameters, and related complications were assessed 10 days, 3 months, and 12 months postoperatively. RESULTS There was no pseudarthrosis, instrumented fusion failure, significant cage subsidence, or retropulsion in any patient. The surgery restored the disc space height and maintained it as of 12 months postoperatively and did not exacerbate the lumbar lordotic and scoliotic angles. All patients had excellent or good outcomes according to the modified MacNab's criteria. The mean pain score according to the visual analogue scale was 7.5 preoperatively but had improved to 2.5 when reassessed 3 months postoperatively. The improvement was maintained as of 12 months postoperatively. CONCLUSION In cases of uncomplicated unilateral radiculopathy, PLIF using a single cage can be an effective and safe procedure with the advantage of preserving the posterior elements of the contralateral side. A shorter operative time and greater cost-effectiveness than for PLIF using bilateral cages can be expected.