Guidelines on How to Perform a Meta-Analysis in Spine Surgery: Strengths and Weaknesses of Design

There are many questions in the literature that remain unanswered due to the paucity of available subjects or the large sample size needed to detect a difference. A meta-analysis consists of integrating together data from multiple studies into one larger data set in order to increase the subject size and power of a paper. In essence, it is a systematic review in which one uses statistical methods to summarize the results of these studies. It is important that a meta-analysis be performed in a systematic and orderly manner with the assistance of a statistician. When carried out correctly, these studies serve as powerful tools to help us better address our knowledge. Because of their complexity, they are prone to bias at multiple levels. This article will discuss the steps involved in performing a meta-analysis, select good studies, as well as explain the statistics conducted in these studies. Furthermore, we will discuss examples from the literature that demonstrate a good meta-analysis.