Comparative effectiveness of dynamic abdominal sonography for hernia vs computed tomography in the diagnosis of incisional hernia.

BACKGROUND

Diagnosis and characterization of incisional hernia are often established by CT, which incurs radiation exposure and substantial cost in clinical practice. The purpose of this study was to determine the comparative effectiveness of surgeon-performed Dynamic Abdominal Sonography for Hernia (DASH) vs CT for incisional hernia evaluation.

STUDY DESIGN

Patients with previous abdominal operations and recent CT imaging were enrolled prospectively; patients with stomas, fistula, or soft tissue infection were excluded. In the clinic setting, DASH was performed with prerequisite training of the American College of Surgeons Ultrasound for Surgeons Basic Course. Clinical evidence of hernia, results of DASH examination, and radiologist documentation of incisional hernia were compared with the gold standard of surgeon-interpreted CT. Testing characteristics of sensitivity and specificity were compared and predictive values were calculated. Inter-rater reliability was performed by comparing DASH results in a subgroup of patients with 3 different evaluators.

RESULTS

There were 181 patients enrolled, with a mean age of 54 years, and 68% were women. In patients in whom hernias were identified, the mean hernia size was 44.6 cm(2) (range 0.2 to 468.3 cm(2)). The DASH examination showed high sensitivity (98%) and specificity (88%). Hernia prevalence was 55% in this population, resulting in positive and negative predictive values of 91% and 97%, respectively. Four patients had clinically detectable hernias that were not seen on CT but were discovered with DASH. Inter-rater reliability for DASH was high, with an observed intraclass correlation coefficient of 0.79.

CONCLUSIONS

The DASH examination is an accurate alternative to CT scan for diagnosing abdominal wall hernias, with additional benefits of no radiation exposure and instant bedside interpretation. The use of DASH to detect hernia recurrence can greatly facilitate long-term follow-up of hernia patients.