M. J. Chaudhary1, R. Smith2, G. Victorino1 1UCSF-East Bay,Surgery,Oakland, CA, USA 2Emory University,Surgery,Atlanta, GA, USA
Introduction:
Computed tomography (CT) is commonly used to evaluate penetrating pelvic organ injury. Rigid sigmoidoscopy may be used as an adjunct in identifying penetrating rectal injury but its sensitivity compared to CT remains unknown. The purposes of this study were: (1) to determine the clinical utility of pelvic computed tomography (CT) in identifying the need for operative intervention after penetrating pelvic trauma, and (2) to determine if rigid sigmoidoscopy, cystogram or retrograde urethrogram improve the diagnostic yield of penetrating pelvic organ injury.
Methods:
We conducted a retrospective review of the trauma registry at our university-affiliated trauma center between January 1999 and December 2016. All patients with penetrating pelvic trauma, who had a CT of the pelvis prior to any potential operative intervention, were included. Operative reports were used to calculate the sensitivity, specificity, negative predictive value (NPV), and positive predictive values (PPV) for CT and rigid sigmoidoscopy in identifying pelvic organ injury.
Results:
During the study period, 160 patients were treated for penetrating pelvic trauma. Overall mortality after penetrating pelvic injury (including combined body compartment trauma) was 16% (26/160). Bladder injuries comprised the majority of injuries (n=86, 54%), followed by injuries to the ureter, blood vessels, and rectum, respectively. Out of the 160 patients with penetrating pelvic trauma, 37% (59/160) underwent preoperative CT scans and 19% (31/160) underwent rigid sigmoidoscopy. A comparison of the sensitivity, specificity, PPV, and NPV of CT and rigid sigmoidoscopy for penetrating rectal injury is attached.
Rigid sigmoidoscopy identified 71% (5/7) of rectal injuries missed by CT. For the remaining two missed injuries, in one case rigid sigmoidoscopy failed to identify an injury and in the other rigid sigmoidoscopy was not performed. CT had a sensitivity of 66%, specificity of 98%, PPV of 67% and NPV of 95% for bladder injury. Cystogram or retrograde urethrogram (RUG) was performed in 3% (5/160) of patients. Cystogram and RUG used in isolation or combination had 100% sensitivity, specificity, NPV and PPV for bladder injury. However, these adjuncts did not identify any injuries missed on CT.
Conclusion:
CT of the pelvis in clinically suitable patients with penetrating pelvic trauma has a low sensitivity and NPV for diagnosing operatively significant rectal or bladder injury. Rigid sigmoidoscopy increases the diagnostic yield for penetrating rectal injury requiring operative intervention. When clinical concern for rectal injury exists following penetrating trauma in the absence of CT findings, rigid sigmoidoscopy is warranted.
