Traumatic urethral injuries: does the digital rectal examination really help us?

INTRODUCTION: The digital rectal examination (DRE) has been commonly employed as a trauma screening tool since the inception of the ATLS program. Because of weak evidence, its utility as a screening test has recently been questioned. The primary goal of this study was to identify the sensitivity of the DRE for detecting blunt urethral injuries in a level 1 trauma center. The secondary goal was to evaluate the interaction of DRE with additional clinical indices of urethral trauma.

METHODS: A retrospective review of all blunt injured patients diagnosed with a urethral disruption at an urban level 1 trauma center from 1995 to 2008 was performed. Urethral injuries were diagnosed by retrograde urethrogram, urethroscopy and operative exploration. Demographics and injury data were collected. The value of the DRE in diagnosing urethral trauma was assessed (p=0.05).

RESULTS: Urethral injuries were diagnosed in 41 male patients (mean age=39 years), 34 (83%) of whom were injured via a motor vehicle (median ISS=21). Associated injuries were present in 40 (95%) patients, including 39 (95%) pelvic fractures. No clinical signs of urethral injury were evident on initial examination in 25 (61%) patients. All patients had hematuria after catheter insertion. An abnormal prostate on DRE, blood at the urethral meatus, and hematuria prior to catheter insertion was present in 1 (2%), 8 (20%) and 7 (17%) patients, respectively. Both meatal blood and hematuria were better screening tests than the DRE (p<0.05).

DISCUSSION: The sensitivity of the DRE for identifying urethral disruption is 2%. The majority of patients with urethral trauma undergo urinary catheterization prior to diagnosis of the injury. Additional signs of disruption including meatal blood and hematuria detected prior to catheter insertion are also infrequent. While the DRE remains clinically indicated in patients with penetrating trauma in the vicinity of the rectum, pelvic fractures, and spinal cord injuries, it appears to be insensitive for detecting blunt urethral injuries.