Validation of a radiographic model for the assessment of mesh migration

Background: The natural history of laparoscopically placed mesh remains uncharacterized. Mesh migration is not infrequently discovered at reoperation and implicated as a cause of hernia recurrence, and it has also been associated with more serious complications, such as enteric and bladder erosion and fistula formation. To date, there is no noninvasive method by which to reliably assess the in-vivo behavior of laparoscopically placed mesh. In this study, we devised and validated a safe and noninvasive model, utilizing computed radiography (CR), for measuring postoperative mesh migration that may be applied to the clinical setting. Methods: The anatomical structures of the inguinal region were recreated using a skeletal male pelvic model. A sheet of commercially available surgical mesh, marked with three 5mm surgical clips at its medial and superior corners, was moved along the inguinal ligament wire for various random distances. The mesh displacement was measured from the model, and a CR film was obtained. The corresponding mesh displacement was then measured on the CR using two different calibration methods (calibration disk and clip measurement). Results: A total of 60 measurements were made and recorded. There were no statistically significant differences between the true (as measured from the model) and CR-measured distances of mesh migration. In comparing the two methods, only method 1 (calibration disk) showed a tendency towards a significant difference when lateral or superior displacement was measured, but correlation remained excellent (r² = 0.99). All other measurements showed no significant difference and excellent correlation (r² > 0.96). Pearson's correlation coefficients showed no significant inter-rater variability using either of these methods. Conclusion: Our CR model reliably provides a noninvasive means to characterize mesh movement in the postoperative clinical setting. This should provide an instrument to facilitate future clinical evaluation of mesh migration in human trials.