Importance: Physical examination misses up to one-third of ventral hernia recurrences seen on radiologic imaging. However, tests such as computed tomographic (CT) imaging are subject to interpretation and require validation of interobserver reliability.
Objective: To determine the interobserver reliability of CT scans for detecting a ventral hernia recurrence among surgeons and radiologists. We hypothesized there would be significant disagreement in the diagnosis of a ventral hernia recurrence among different observers. Our secondary aim was to determine reasons for disagreement in the interpretation of CT scans.
Design, setting, and participants: One hundred patients who underwent ventral hernia repair from 2010-2011 at an academic health care center with a postoperative CT scan were randomly selected from a larger cohort. This study was conducted from July 2014 to March 2015. Prospective assessment of the presence or absence of a recurrent ventral hernia on CT scans was compared among 9 blinded reviewers and the radiology report. Five reviewers (consensus group) met to discuss all CT scans with disagreement. The discussion was assessed for keywords and key concepts. The remaining 4 reviewers (validation group) read the consensus group recommendations and reassessed the CT scans. Pre- and post-review κ were calculated; the post-review assessments were compared with clinical examination findings.
Main outcomes and measures: Interobserver reliability in determining hernia recurrence radiographically.
Results: Of 100 CT scans, there was disagreement among all 9 reviewers and the radiology report on the presence/absence of a ventral hernia in 73 cases (κ = 0.44; 95% CI, 0.35-0.54; P < .001). Following discussion among the consensus group, there remained disagreement in 10 cases (κ = 0.91; 95% CI, 0.83-0.95; P < .001). Among the validation group, the κ value had a slight improvement from 0.21 (95% CI, 0.12-0.33) to 0.34 (95% CI, 0.23-0.46) (P < .001) after reviewing the consensus group proposals. There was disagreement between clinical examination and the consensus group assessment of CT scans on the presence/absence of a ventral hernia in 25 cases. The concepts most frequently discussed were the absence of an accepted definition for a radiographic ventral hernia and differentiating pseudorecurrence from recurrence.
Conclusions and relevance: Owing to the high interobserver variability, CT scan was not associated with reliable diagnosing in ventral hernia recurrence. Consensus guidelines and improved communication between surgeon and radiologist may decrease interobserver variability.