Objective: To describe a novel ipsilateral interlaminar uniportal endoscopic approach for L5–S1 foraminal decompression that enables both lateral recess and foraminal decompression through a single interlaminar window.

Methods: Five patients with unilateral L5–S1 foraminal stenosis and radiculopathy unresponsive to conservative therapy underwent endoscopic decompression using the ipsilateral interlaminar approach. The technique involves the surgeon initially standing ipsilateral for lateral recess decompression and then switching to the contralateral side to complete foraminal decompression through the same portal.

Results: All five patients tolerated surgery well and were discharged the same day. Postoperative follow-ups at 2 weeks, 6 weeks, 3 months and 6 months demonstrated improved pain scores. The technique provided direct visualization of the traversing and exiting nerve roots, allowed adequate decompression with minimal bone resection, and eliminated the need for a separate transforaminal window.

Conclusion: The described ipsilateral interlaminar uniportal endoscopic approach provides a safe and efficient alternative for L5–S1 foraminal decompression, overcoming limitations of the transforaminal route in cases with a high iliac crest. The method is intuitive for surgeons familiar with interlaminar endoscopy and offers optimal decompression through a single portal. Larger prospective studies are warranted to validate these findings.