Exploring the Extended Latissimus Dorsi Myocutaneous Flap: A 55 Cadaver Study

Background: The latissimus dorsi muscle has long been a valuable muscle for reconstruction. Our study aims to determine the true anatomic origin of the latissimus dorsi muscle and identify the possibility of performing an extended musculocutaneous flap for better aesthetic outcome and avoiding the need of implant based reconstruction to add volume. Methods: 55 human cadaver bodies were dissected to evaluate the origin attachment point. Our aims were to determine how frequently the latissimus dorsi flap can be extended distally and determine its origin of attachment as the thoracolumbar fascia alone or in combination with the posterior iliac crest. Results: The latissimus dorsi muscle had a 62% rate of muscular origin attachment being the thoracolumbar fascia alone, and a 38% rate of muscular origin of attachment being the thoracolumbar fascia in combination with the posterior iliac crest. The muscle was found to be shorter when the origin was the thoracolumbar fascia as opposed to when the origin was the thoracolumbar in combination with the posterior iliac crest. When the LD muscles origin was the thoracolumbar fascia alone the quadratus lumborum attached to the PSIS. Conclusion: As such a valuable reconstructive tool, we have underutilized and failed to harvest the full extent of the latissimus dorsi muscle. The lack of mobilization lies in the failure to understand the origin, the posterior iliac crest, in minority of patients. When the latissimus dorsi muscular origin of attachment is both the thoracolumbar fascia and posterior iliac crest, a distally extended flap can be designed, which will result in better aesthetic outcome for breast surgery.