Lumbar Spinal Stenosis and Minimally Invasive Lumbar Decompression: A Narrative Review

Background: Lumbar spinal stenosis (LSS) is a common pain condition that causes lumbar back pain, radiating leg pain, and possible functional impairment. MILD is an emerging minimally invasive treatment for LSS. It is an image-guided percutaneous procedure designed to debulk hypertrophied ligamentum flavum. However, the exact short-and long-term efficacy, safety profile, indication criteria, and certain procedure details reported in medical literature vary. Objective: This narrative review was to elucidate efficacy, safety profile, certain procedure details, advantages, and limitations of MILD. Study Design: This is a narrative review. Setting: All included articles are clinic trials including analytic studies and descriptive studies. Methods: PubMed, Cochrane Library, and Scopus were searched. Only clinical trials of MILD procedure were included. Information of indications, contraindications, VAS scores, ODI scores, effective rate, efficacy durations, and certain procedure details was focused on. Results: According to the literature, for the MILD procedure, the VAS score could be reduced from a pre-treatment level of 6.3–9.6 to a post-treatment level of 2.3–5.8. The ODI score could be reduced from a pre-treatment level of 38.8–55.3 to a post-treatment level of 27.4–39.8. The effective rate of the MILD procedure was reported to be 57.1%–88%. A 2-year postoperative stability of efficacy was also supported. One RCT study testified superior efficacy of MILD over epidural steroid injection. Limitations: There is few high-quality literature in the review. Moreover, the long-term efficacy of MILD cannot be revealed according to the current literature. Conclusion: Based on the reviewed literature, MILD is an effective and safe procedure. MILD can reduce pain intensity and improve functional status significantly. Therefore, it is a preferable option for LSS patients who failed conservative treatments, but not for those who require immediate invasive decompression surgery.