[<< Reverse >> latissimus dorsi musculocutaneous flap: anatomic study of the secondary pedicles]

The latissimus dorsi flap based on the secondary segmental vessels, wich is termed << reverse >> or << distally based >> latissimus dorsi flap, has been used to repair major thoraco-lumbar defects, to close myelomeningoceles and to reconstruct congenital diaphragmatic absences. The arc of flap rotation is markedly restricted because the blood supply is segmental. It is the most important factor that limits the flap mobility and so restricts its use. The authors report an anatomic study of these secondary pedicles in order to improve the flap dissection and to extend the arc of flap rotation.

The precise location of the secondary pedicles of the flap was determined by 24 anatomic dissections.

The latissimus dorsi has 3, 4 or 5 secondary pedicles respectively in 50%, 25% and 25% of cases in the study. These pedicles take origin from the dorsal branches of the posterior intercostal arteries of the 7th, 8th, 9th, 10th and 11th intercostal spaces.

The number of secondary pedicles is not constant. The entire flap can be safely based on 2 secondary pedicles when the latissimus dorsi muscle has 3 secondary pedicles. When this muscle has 4 or 5 secondary pedicles, the entire flap should be at least based on 3 secondary pedicles, particularly if the skin island is very far from the origin of these vessels.