Morphometric study (macroscopic and microscopic) of the lower abdominal wall.

Background: Abdominoplasty using a more superficial plane of dissection has several advantages. Previous studies described a trilaminar structure (superficial and deep fat compartments separated by the Scarpa fascia) in the lower abdominal wall. This study aimed to gain a clearer understanding of compartment dominance and changes with increasing adiposity.

Methods: The study was performed on the surgical specimens of 41 female patients submitted to a full abdominoplasty. A morphometric study was performed on 82 sides to evaluate the thickness of the fat layers at predetermined locations (point A over the external oblique muscle and point B over the rectus abdominis muscle). A histologic study was performed in 31 samples to analyze the structure of the fat compartments and Scarpa fascia.

Results: A trilaminar structure was always present, and the Scarpa fascia did not become vestigial with increasing adiposity. Total thickness at point B was significantly higher than that at point A; this difference was mainly attributable to the superficial compartment. The deep fat compartment was always thinner than the superficial, corresponding to 25 percent of total thickness in point A and 23 percent in point B. It was less susceptible to an increase in thickness in cases of obesity. Histologic analysis demonstrated constant morphology, with an average Scarpa fascia thickness of 0.29 mm (point A) and 0.28 mm (point B).

Conclusions: This study demonstrates a trilaminar structure with superficial compartment dominance and Scarpa fascia presence irrespective of adiposity in the lower abdominal wall. The deep fat compartment has a minor contribution to the lower abdominal wall thickness.