Sequential Full-Endoscopic Decompression under Local Anesthesia for Concurrent L4/5 Lateral Recess and L5/S1 Foraminal Stenosis Due to Stable Isthmic Spondylolisthesis: A Case Report.

Isthmic spondylolisthesis at the L5-S1 level frequently leads to foraminal stenosis, while degenerative changes often cause lumbar spinal canal stenosis at L4-5. When both conditions coexist, accurate identification of the symptomatic lesion is challenging. Conventional surgical strategies typically involve combined decompression and interbody fusion under general anesthesia, which may not be suitable for elderly or high-risk patients. Recent advances in full-endoscopic spine surgery performed under local anesthesia provide a minimally invasive alternative. In this report, we present the case of a 75-year-old man with L5 radiculopathy in whom magnetic resonance imaging demonstrated right-sided lateral recess stenosis at L4-5 and right-sided foraminal stenosis at L5-S1 due to stable isthmic spondylolisthesis. Two-stage full-endoscopic spine surgery was performed under local anesthesia. The first procedure involved transforaminal pars crisscross decompression at L5-S1. Although foraminal decompression was achieved, symptoms persisted. A second-stage full-endoscopic ventral facetectomy at L4-5 resulted in immediate resolution of his symptoms. The patient remained asymptomatic at the 3-month follow-up. This case highlights the feasibility and efficacy of sequential full-endoscopic decompression under local anesthesia for multilevel lumbar stenosis associated with L5 radiculopathy. This approach may serve as a safe, less invasive alternative to fusion surgery in elderly patients and those with significant comorbidities.