Cryptorchidism (over 90% in some studies). Even after orchiopexy, these may also affect sperm maturation and motility at an older age. The most common diagnostic dilemma in otherwise normal boys is distinguishing a retractile testis from a testis that will not descend spontaneously into the scrotum. Retractile testes are more common than truly undescended testes and do not need to be operated on. In normal males, as the cremaster muscle relaxes or contracts, the testis moves lower or higher ("retracts") in the scrotum. This cremasteric reflex is much more active in infant boys than older men. A retractile testis high in
Users' Guides to the Medical Literature Guyatt introduced the term "evidence-based medicine" to stress the role of rigorous, systematic evidence from clinical research in conjunction with patients’ values and preferences in clinical decision-making. A group of academic physicians subsequently formed the international Evidence-based Medicine Working Group and published a 1992 article announcing the "new paradigm" of evidence-based medicine. The Evidence-based Medicine Working Group decided to build on the popular series in the "Canadian Medical Association Journal" by creating a more practical approach to applying the medical literature to clinical practice. Championed by Dr. Drummond Rennie, an editor of the "Journal of the American Medical Association", the