Posterior intercostal flap: an anatomical study and best flap design

Posterior intercostal arteries perforators (PICAPs) and lateral intercostal arteries perforators (LICAPs) are great vascular pedicles. Between the 4th and 11th spaces, they arise from the thoracic aorta. These are large perforators that can be the basis of many flaps. Yet, these perforators are underrated as they are poorly studied and scarcely utilized in plastic reconstructions.

Twenty (ten males and ten females) adult cadaveric dissections were done on both sides to study the types, locations, and sizes of posterior intercostal perforators to help design flaps based on them in the best possible way. Perforators were assigned into one of 3 topographical zones of the back (medial, intermediate, and lateral).

The skin of the back was divided into 3 vertical zones: medial, intermediate, and lateral. Posterior intercostal arteries perforators (PICAPs) were found in the medial and intermediate zones. Medial zone PICAPs were large and appeared at the medial border of erector spinae (Es). Intermediate zone PICAPs appeared at the lateral border of Es and passed through latissimus dorsi (Ld) before reaching the skin. Lateral zone perforators were branches of lateral intercostal arteries and were divided into 2 types: (1) posterior branches of lateral intercostal perforators: simply named posterior lateral perforators (PLs); they were small and present in most of the spaces, and (2) anterior branches of lateral intercostal perforators (LICAPs): they were large, dominant pedicles and were found mainly in the 4th to the 7th spaces.

PICAPs and LICAPs are constant and of enormous size and run for a great distance in the skin. They can be utilized as any type of flap.