Changes in the abdominal wall after anterior, posterior, and combined component separation.

KEY MESSAGE Knowledge of the changes that occur in the abdominal wall after component separation (CS) is essential for understanding the mechanisms of action of the various CS techniques, the changes observed on computed tomography images, and, perhaps most importantly, the anatomic and physiologic changes observed in patients who have undergone CS. Purpose Component separation (CS) techniques are essential adjuncts during most abdominal wall reconstructions. They allow the fulfillment of most modern abdominal wall reconstruction principles, especially primary closure of defects and linea alba restoration under physiologic tension. Knowledge of the post-CS abdominal wall changes is essential to understanding the mechanism of action of the various types of CS, the changes observed on computed tomographic images, and, perhaps most importantly, the anatomic and physiologic changes following CS techniques. Methods A systematic review of the literature was conducted using the PubMed database and other sources to identify articles describing abdominal wall changes after CS Results After excluding non-pertinent articles, 14 articles constituted the basis for this review.  Conclusions After reviewing the literature on post CS abdominal wall changes, we conclude the following: (1)The external oblique muscle is significantly displaced laterally after anterior CS, the transversus abdominis muscle shifts very little after posterior CS, and muscle trophism is generally maintained after both techniques. These findings are consistent for both open and minimally invasive CS. (2) The anatomy and physiology of abdominal wall muscles are preserved mainly by the muscles' overlapping function and their ability to undergo compensatory trophism after midline restoration (reloading). (3) Well-performed CS techniques have a low risk of producing bulging and semilunar line hernias. (4) Anterior and posterior CS techniques probably have different mechanisms of action. (5) Current studies on how the nutritional status and postoperative conditioning can alter abdominal wall changes after CS and the mechanisms of the actions involved in anterior and posterior CS are underway.