Objective: Spinal stenosis and degenerative spinal disorders are increasingly prevalent and have a substantial impact on quality of life. Surgical decompression, performed using either open microscopic or endoscopic approaches, remains a cornerstone of management for these conditions. This study examines evolving trends in single-level lumbar spinal decompression procedures performed at a tertiary academic hospital in Singapore. Methods: A retrospective observational study was conducted involving 588 patients who underwent single-level spinal decompression between 2021 and 2024, including endoscopic spine surgery (ESS; n=364) and microdecompression (n=224). Primary outcome measures were changes in 36-Item Short Form Health Survey (SF-36) and visual analogue scale (VAS) scores at 3 months, 6 months, and 2 years postoperatively. Secondary outcomes included length of hospital stay, reoperation rates, and operative time. Patient demographics, spinal level and pathology characteristics, surgical techniques, and postoperative outcomes were analyzed. Difference-in-differences (DID) analysis was used to compare outcomes between the 2 groups. Results: Both groups demonstrated significant postoperative improvements in SF-36 and VAS scores. At 2 years, Short Form Health Survey physical function (SFPF) scores improved in the endoscopic group (mean difference [MD], 18.6; standard deviation [SD], 21.7; p=0.064) and in the open microscopic group (MD, 36.7; SD, 20.9; p=0.007), with a non-significant DID of -18.1 (p=0.155). No DID comparisons across SF-36 domains reached statistical significance. Mean operative time for endoscopic procedures decreased from 249 minutes in 2022 to 145 minutes in 2024, reflecting a procedural learning curve. Surgeons with higher endoscopic caseloads exhibited greater improvements in functional outcomes. Conclusion Both endoscopic and open microscopic decompression achieve comparable short- and long-term clinical outcomes. ESS provides similar effectiveness while being associated with shorter recovery periods and reduced hospital stay. Further research is warranted to identify factors contributing to incomplete symptom resolution or the need for revision surgery.