Large ventral hernias are known to induce atrophic changes to the anterior abdominal wall musculature. We have shown that anterior component separation with external oblique (EO) release, with resultant reconstruction of the midline, results in hypertrophy of the rectus muscle (RM), internal oblique (IO), and transversus abdominis (TA). We aimed to compare and contrast the impact of posterior component separation with transversus abdominis release (TAR) and bridging laparoscopic ventral hernia repair (LVHR) on the muscles of the abdominal wall.

Preoperative and at least 6-month postoperative CT scans were analyzed for patients undergoing TAR with midline reconstruction and LVHR without midline reconstruction. A change in the measured area of each abdominal wall muscle was used as the determinant of hypertrophy or atrophy. The areas of the RM, EO, IO, and TA were measured at the L3 to L4 level through the axial plane.

Twenty-five consecutive patients with pre- and postoperative images were analyzed in each group. In the TAR group, the RA, EO, and IO demonstrated significant increases in area. In the LVHR group, no muscles demonstrated any significant changes.

Similar to anterior component separation, hernia repair with TAR results in hypertrophy of the rectus abdominis muscle. In addition, we found that TAR was associated with hypertrophy of both external and internal oblique muscles. Bridging repair during LVHR, on the other hand, did not result in any significant changes in any of the abdominal muscles. Our findings provide clear radiologic evidence that re-creation of the midline by means of the TAR leads to improved anatomy of the abdominal wall, in addition to positive compensatory changes of the lateral abdominal wall musculature.