Study design: This article reviews the criteria for evaluating the quality of clinical trials.
Objectives: To outline the current methodologic standards by which the validity of controlled trials need to be evaluated.
Summary of background data: Weber's study, published in 1983 in Spine, is the only randomized trial comparing surgery and conservative management of sciatica in herniated lumbar discs.
Methods: Weber's article is revisited to illustrate basic principles in the design of clinical trials.
Results: Weber's study is a classic in spine surgery and has changed thinking regarding the benefit of surgery in sciatica related to herniated lumbar discs. However, the authors found potentially critical flaws in this study: a large number of crossovers, inadequate sample size, and insensitive outcome measurements.
Conclusions: A randomized, controlled trial is the most rigorous way to evaluate health intervention. Despite the difficulties of performing such studies, investigators should use the most appropriate scientific methodology.