Can the snapping sound discriminate true from false penile fractures? Bayesian analysis of a case series of consecutively treated penile fracture patients.

Some patients with clinically diagnosed penile fracture actually have a false fracture (no tunica albuginea tear found at surgery). Although previous reports indicate that these patients often do not report hearing a snapping sound (henceforth sound) at injury, there are no studies of the sound's role in this differential diagnosis. To assess if the sound's absence increased the likelihood of intraoperatively diagnosing a false fracture, we retrospectively analyzed 65 consecutive clinically diagnosed penile fracture patients between January 2008 and December 2017, using surgical diagnosis of penile fracture as outcome variable and sound as main predictor, including as covariates age, presentation delay, immediate detumescence after injury, and whether injury occurred during sexual intercourse. Fifty-six patients had penile fracture (86.2%), and most (40, 71.4%) reported the sound, whereas two of the nine patients with false fracture reported the sound (22.2%, p = 0.007, Fisher's exact test). Bayesian logistic regression revealed that the sound was associated with surgical diagnosis of penile fracture (relative odds ratio = 4.25), and the probability of penile fracture fell from 92 to 74% when the sound was not reported among patients injured during intercourse experiencing immediate detumescence. This study followed PROCESS (Preferred Reporting of Case Series in Surgery) guidelines.