Background and objectivesLumbar ligamentum flavum cyst is a rare spinal condition that can cause significant morbidity and neurological deficits. Traditional surgical treatment involves open surgery, which can be associated with prolonged recovery time and significant morbidity. In recent years, endoscopic treatment of lumbar ligamentum flavum cyst has emerged as a minimally invasive and effective alternative to open surgery, but only a few cases have been reported in the literature. This paper describes our experience with endoscopic resection of an L4/5 ligamentum flavum cyst through an interlaminar approach and reviews the literature on the treatment of lumbar ligamentum flavum cyst.MethodsAn 87-year-old man presented with lameness in the left leg, and magnetic resonance imaging (MRI) showed nerve compression by a ligamentum flavum cyst at the L4/5 intervertebral plane. The patient underwent endoscopic resection of the ligamentum flavum cyst through a left interlaminar approach with the facet joint preserved. The present study was approved by the Ethics Committee of our hospital. The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request. Text regarding patient consent is not applicable for this case.ResultsPostoperative clinical results improved significantly, and postoperative MRI showed complete cyst resection.ConclusionTotal endoscopic resection via an interlaminar approach provides a new minimally invasive approach for the surgical treatment of lumbar ligamentum flavum cyst, which can be used as a reference by clinicians.