SPINE SECTION Review Article The mild® Procedure: A Systematic Review of the Current Literature

Objectives. This study's objective was to deter- mine if the literature supports use of the Minimally Invasive Lumbar Decompression (mild®) proce- dure (Vertos Medical, Aliso Viejo, CA, USA) to reduce pain and improve function in patients with symptomatic degenerative lumbar spinal stenosis. Design/Settings. The study was designed as an evidence-based review of available data. Studies were identified from PubMed, Embase, and the Cochrane Library. Articles were evaluated using the Grading of Recommendations Assessment, Development and Evaluation Working Group system. Results were compiled assessing short- (4-6 weeks), medium- (3-6 months), and long-term (>1 year) outcomes. The primary outcomes evalu- ated were pain, measured by the visual analog scale (VAS), and function, measured by the Oswestry Dis- ability Index (ODI). Secondary outcomes included pain and patient satisfaction, measured by the Zurich Claudication Questionnaire, adverse effects/ complications, and changes in utilization of co-interventions. Results. The literature search revealed one random- ized controlled trial (RCT) and 12 other studies (seven prospective cohort, four retrospective, and one case series) that provided information on the use of mild® in patients with degenerative lumbar spinal stenosis. All studies showed statistically sig- nificant improvements in VAS and ODI scores at all time frames compared with preprocedure levels; the RCT showed improvement over controls. Categori- cal data were not provided; thus, the proportion of patients who experienced minimal clinically mean- ingful outcomes is unknown. Conclusion. The current body of evidence address- ing mild® is of low quality. High-quality studies that are independent of industry funding and provide categorical data are needed to clarify the propor- tions of patients who benefit from mild® and the degree to which these patients benefit. Additional data at up to 2 years are needed to determine the overall utility of the procedure.