Enduring diastasis repair is one of the yardsticks by which a successful abdominoplasty is measured, because the presence and size of diastasis recti are thought to be reliable indicators of abdominal wall laxity and protrusion. The author's study of the “normal” anatomy of diastasis challenges these concepts about diastasis recti.
Ninety-two consecutive abdominoplasty patients, in whom intraoperative measurements of the linea alba were taken, were included in this study. The degree of abdominal wall protrusion was quantified by estimating the intra-abdominal fat volume in the upright patient as large, medium, or small.
The most striking anatomical finding was that the linea alba has a limited range of stretch, most commonly between 1 and 2 inches, regardless of the extent of the abdominal girth. Moreover, eight patients with diastasis did not manifest abdominal protrusion, and in five patients, diastasis was absent, although a significant protrusion was present. Also, the site of the widest diastasis (supraumbilical/infraumbilical) frequently did not correspond to the site of the protrusion.
Contrary to current thought, abdominal wall protrusions are caused by the stretching of the entire abdominal wall and not only the linea alba. Thus, significant abdominal wall protrusions may occur without diastasis and flat abdomens may exhibit a diastasis. Abdominal protrusion should replace diastasis as the prime indicator of abdominal wall laxity; stretching and the decision to perform diastasis repair should be influenced primarily by the evaluation of the protrusion rather than the diastasis.