Spine 2026;51(22):1577–1589
For adults with severe single-level lumbar stenosis, unilateral endoscopic decompression through one or two portals produced similar pain and disability scores at one year. The clearest difference was in operating time. The biportal procedure was nine minutes faster at the median, although the surgeon also used different instruments for bone removal in the two groups.
Study and key findings
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Liu and colleagues randomized 110 adults with Schizas grade C or D stenosis and persistent radicular symptoms or neurogenic claudication after at least three months of conservative treatment. Patients with spondylolisthesis, dynamic instability or previous lumbar surgery were excluded. One surgeon performed all procedures, with 55 patients assigned to each technique.
Median operating time was 88 minutes with two portals and 97 minutes with one. Median postoperative stay was three and two days, respectively. Early imaging showed similar dural sac expansion and facet preservation. At 12 months, 90.9% of the biportal group and 89.1% of the single-port group had good or excellent modified Macnab outcomes in the intention-to-treat analysis. One dural tear occurred in the single-port group and was managed conservatively.
Interpretation and limitations
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Separate viewing and working portals let the surgeon angle the instrument independently of the endoscope. The biportal procedure also used a high-speed drill, whereas a trephine was used exclusively in the single-port group. The time difference therefore reflects the instruments and the operator’s experience as well as portal configuration. Pain and disability were first assessed at three months, so the shorter single-port hospital stay provides little evidence about early symptom relief.
Clinical takeaway
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When counseling a patient with severe stenosis confined to one stable level, either approach is reasonable if the surgeon can decompress both lateral recesses while preserving the facets. The one-year results support choosing the system the team handles well. Longer follow-up is needed to compare recurrent stenosis and late instability.