The partial superior latissimus (PSL) flap
The psl Flap
Muscle flap. May be harvested with a skin paddle. Up to 22 cm long and up to 15 cm wide at the widest point.
Innervation: Transverse branch of the thoracodorsal nerve.
Blood supply: Transverse branch of the thoracodorsal artery.
Artery: 1 mm when taken on the transverse branch. Can be up to 3 or 4 mm if harvested up to the subscapular artery.
Vein(s): Comparable to the artery. Two venae for the transverse branch, only one commitantes branch with the subscapular.
Pedicle length: Up to 15 centimeters.
The partial superior latissimus muscle provides a long pedicle and large, thin muscle that can be innervated. The lateral aspect and innervation of the latissimus muscle are spared, preserving lateral muscle function and the dorsal thoracic silhouette. The flap can cover both large and small defects and provides a very long vascular leash, allowing reconstruction of complex deformities
Anatomy
The partial superior latissimus muscle relies on inflow from the transverse branch of the thoracodorsal artery. The branch arises intramuscularly, after the thoracodorsal vessels and nerve enter the muscle on it's deep surface in the posterior axilla.
The Partial Superior Latissmus Muscle Anatomy
Flap Dissection
The patient is positioned and prepped similar to a latissimus muscle harvest. The inferior angle of the scapula is palpated and guides the surgeon to the superior extent of the latissimus muscle. The incision is drawn a finger breadth or two inferior to this, along the axis of the fibers of the upper latissimus. A skin paddle can be designed over this muscle.
Markings for the PSL Harvest
An inferior skin flap is created superficial to the muscle. The upper border of the latissimus is identified and the muscle is then retracted away from the chest wall, to expose the undersurface. The dissection proceeds toward the axilla, and the thoracodorsal artery and accompanying vein are identified as they enter the muscle. The pedicle is freed proximal to entry point, and the transverse and descending branches of the artery are identified. The descending branch of the nerve must be spared to preserve innervation to the lateral muscle.
The muscle is elevated from the chest wall to identify the transverse artery branch
A marking pen is used to outline the extent of the PSL flap and the muscle dissection is performed with scissors and the bipolar electrocautery. If a long pedicle is desired, the artery is traced to the subscapular origin on the axillary vessels.
The Extent of the Flap is then Outlined
The skin defect is closed in layers over a suction drain.
The harvested partial superior latissimus
Postoperative Care
We allow the patient to use the ipsilateral arm postoperatively and no special dressings are required. The donor area should be inspected daily for hematoma formation. This donor area can form a seroma, necessitating drains.