[Advances of studies on needle retention time in acupuncture treatment]

Needle retention is one of the important links in clinical acupuncture, thus, ancient medical scholars emphasized its value. This paper summarizes and evaluates the recent literature about needle retention time in terms of course of disease, category of disease, patient's condition and acupuncture location. The modern researches verify and develop the knowledge of needle retention in ancient times. However, study designs of randomized controlled trial for evidence-based medicine are not many, most of which are observational studies. In the future, clinical research need to apply scientific design based on Chinese medicine theory to investigate the principles of needle retention and the optimized needle retention time. This will consequently guide the standardization and systemization of acupuncture in clinical practice.