Authors: Caroline Lilja, MD., Emma Tubæk Nielsen, stud.med., Magnus Balslev Avnstorp, MD., and Stephan Thunich, MD.

1. If desired, the thoracodorsal artery can be identified and marked, using a Doppler scanner preoperatively. Because of its reliable anatomy, this is most often unnecessary. ¹
2. The patient is placed on the operative table in a lateral position, with the ipsilateral arm abducted and fixated anteriorly and superiorly on a padded stand, before the surgical field is prepped.
   • Depending on the preference of the surgeon, the arm may be included in the sterile field, allowing it to be moved freely during the procedure.
3. The border of the latissimus muscle is outlined using a skin marker.
4. The flap is marked preoperatively in a standing position. To do this, the patient should abduct the arm by 90 degrees.
   • The flap is often designed over the upper half to two-thirds of the muscle, where the highest density of cutaneous perforators is located.The surgeon might as a guidance, using a skin marker, mark both sides of the epidermis surrounding the designed skin island to align the edges when closing the wound after the harvest is complete.
   • In cases where a skin island is not desired, simply mark the incision site extending from the posterior axillary fold reaching inferiorly and medially over the latissimus dorsi muscle.
5. An incision is made starting at the posterior axillary fold following the outline of the skin island.
6. Dissection of the subcutaneous tissue fat down to the latissimus muscle is then performed, exposing the muscle (the muscle fascia should be left intact).
7. If an oblique dissection is planned, it should be performed below the subcutaneous fascia.
8. Once the superior and lateral border of the latissimus dorsi muscle is identified, the inferior portion of the muscle is divided.
9. The muscle is divided at the desired width, depending on the size of the defect in the specific case, before elevating the muscle from interior to superior. Care is taken to identify and ligate any perforators arising during the dissection.
   • The muscle has strong perforators from the thorax
10. Once the muscle is elevated and perforators are ligated, the dissection of the pedicle may begin.
11. The vascular pedicle enters the muscle in the anterior third of the muscle about 9-12 cm caudal to the axilla. It usually runs 2-3 cm dorsal to the anterior edge of the muscle. If perfusion from the thoracodorsal bundle is safe, the branch leading to the serratus muscle can be ligated. This makes the flap more mobile.
12. The pedicle is carefully dissected cranially, smaller branches are ligated. At the level of the caudal axilla there are branches to the teres major muscle and the scapula. These must be carefully ligated.
13. Once close to the muscle’s insertion at the humerus, the thoracodorsal nerve is identified and divided.
    • Care should be taken to preserve the medial branch of the nerve, to maintain motor function of the remaining part of the muscle.
14. In cases of free tissue transfer, the pedicle is clamped and divided. The flap is now ready for transfer to the reconstructive site. Arterial and venous anastomosis requires microsurgical techniques.
15. In cases where a pedicle flap is desired, the artery is preserved after dissection, and the flap can be transferred to the reconstructive site by transposition.
    • The transposition of the flap requires a tunnel created subcutaneously or through a muscle.
16. The tendon insertion of the muscle can be temporarily fixed to the anterior edge of the pectoralis muscle to prevent traction on the pedicle during repositioning of the patient.
17. A drain is inserted at the donor site before closing directly using sutures.¹

References

1. Little S. C. Latissimus Myocutaneous Flap. Medscape, Clinical Procedures. 17.06.2019. https://emedicine.medscape.com/article/880878-overview#showall