Reduction-First Technique of Unilateral Biportal Endoscopy Lumbar Interbody Fusion for Spondylolisthesis

The reduction-first technique in unilateral biportal endoscopy (UBE) lumbar interbody fusion is a novel approach designed to overcome the limitations of conventional UBE fusion for spondylolisthesis. UBE fusion has gained popularity as a minimally invasive procedure, yet its ability to achieve satisfactory vertebral reduction remains limited, particularly in patients with higher-grade spondylolisthesis. This paper introduces a modified technique in which a right-sided pedicle screw is placed prior to cage insertion, facilitating early reduction of spondylolisthesis and improving interbody cage positioning. By addressing both the ipsilateral and contralateral facet joints under endoscopic visualization, the reduction-first technique enhances reduction and disc height restoration while maintaining minimal invasiveness. We present 2 clinical cases in which this technique was successfully applied, resulting in significant improvements in lumbar lordosis, sagittal vertical alignment, and clinical outcomes. Immediate postoperative radiographs and follow-up imaging demonstrated improved reduction and solid fusion at 6 months postoperatively. Although long-term outcomes have not yet been determined, this technique shows promise in expanding the indications for UBE fusion, even in patients with higher-grade spondylolisthesis.