Comparison of ultrasonography and physical examination in the diagnosis of incisional hernia in a prospective study.

Purpose: Incisional hernia is a frequent complication of abdominal surgery (incidence 2-20%). Diagnosis by physical examination is sometimes difficult, especially in small incisional hernias or in obese patients. The additional diagnostic value of standardized ultrasonography was evaluated in this prospective study.

Methods: A total of 456 patients participating in a randomized trial comparing two suture materials for closure of the abdominal fascia underwent physical examination and ultrasonography at 6-month intervals. Wound complaints and treatment of incisional hernia were also noted. Statistical analysis was performed using the Chi-squared and Fisher's exact tests (SPSS). Interest variability analysis was performed.

Results: During a median follow-up of 31 months, 103 incisional hernias were found. A total of 82 incisional hernias were found by physical examination and an additional 21 with ultrasonography. Six of these additional hernias were symptomatic and only one of the additional hernias received operative treatment. The false-negative rates for physical examination and ultrasonography were 25.3 and 24.4%, respectively. Interest variability was low, with a Kappa of 0.697 (P < 0.001).

Conclusions: There are no clear diagnostic criteria for incisional hernia available in the literature. Standardized combination of ultrasonography with physical examination during follow-up yields a significant number of, mostly asymptomatic, hernias, which would not be found using physical examination alone. This is especially relevant in research settings.