Coverage of Massive Brain and Skull Defects with Latismus Dorsi Free Flaps

Latissimus Free Flaps for Massive Brain and Craniofacial Skull Wounds

Large defects of the craniofacial skull that are created from cancers, trauma, radiation, or other causes, often require microvascular free tissue transfer to close the wounds. On the vertex of the skull, there is limited tissue to close even small wounds and the amount of tissue is often decreased even more significantly if the tissue mobility is affected by radiation. The transfer of free muscle allows the operative surgeon to 1) cover any open wounds and 2) obliterate dead space which can often cause recurrent or recalcitrant infections.

Massive wounds of the brain and skull require complete debridement of all devitalized, radiated, necrotic, and osteomyelitic bone to allow the wound to heal properly. After all of the necrotic and devitalized material has been debrided, then the microsurgeon can bring well vascularized tissue to the area to help heal the wound.

The latissimus dorsi offers the most optimal muscle to be transferred to the scalp as it has a broad surface area to cover the entire scalp. The size match of the thoracodorsal vessels also coincide well with the size match of the superfical temporal artery and vein to allow an appropriate size match. It is important for the operative surgeon to be prepared to harvest either the greater saphenous vein or the lesser saphenous vein in the lower extremity in case the superficial temporal vein is inadequate. In this case the venous anastamosis needs to be jumped to the external jugular vein in the neck. This should be marked out pre-operatively and no central venous lines placed on that side of the neck pre-operatively.

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Latisimus Flap for Closure of Complex Posterior Trunk Radiation Wounds

Radiation is often a necessary adjuvant in the treatment of many cancers. While radiation is often necessary in cancer therapy, the radiation can also cause damage to normal healthy tissue and prevent wound healing.

Closure of the radiated wound is often one of the most challenging problems the Plastic & Reconstructive Surgeon can face. The key to closing radiated wounds is adequate debridement. Often adequate debridement can create a much larger wound that the original and often much larger than anticipated by both patient and surgeon.

After adequate debridement has been performed, the next important step in reconstruction is to make sure that healthy tissue is brought into the area affected to allow wound closure. In some cases, tissue from an adjacent area of the body can be used, occasionally regional tissue may be used, and in some cases distant tissue is used to be brought into the area to allow wound closure. When tissue from a remote area of the body is used, this is called free tissue transfer or microsurgical anastomosis.

In this case a large posterior trunk wound was present after successful cancer removal and successful radiation therapy. The wound was thoroughly debrided to relatively healthy tissue. A wound VAC was then placed on the posterior trunk to promote blood perfusion and as a bridge to determine the final wound size and plan reconstruction.

In this case, a latisimus myocutaneous flap was used to bring both muscle to cover exposed bone and skin to fill a defect. A small skin graft was placed on the latisimus muscle to prevent too tight of a wound closure. The skin graft however contracts over time and can often eventually be excised and the wound closed with one skin paddle.

Latisimus Dorsi Myocutaneous Flap with Extended Skin Paddle for Cross Midline Chest Wall Defects

The latissimus dorsi myocutaneous flap continues to be one of the workhorse flaps used in Plastic & Reconstructive Surgery. The words latissimus dorsi means "broadest of the back" and it is this characteristic that allows it to cover large defects locally, regionally, and for distant transfer. The latissumus dorsi muscle is a Nahai & Mathes type V muscle with its blood supply originating from the thoracodorsal vessels as well as paraspinal lumbar perforators.

I have found that the extent of the skin paddle used for the latissumus dorsi can be extended beyond those stated in standard textbooks. The skin paddle can be as wide as the breadth of the muscle and allow primary closure in the back. The length of the skin paddle can be upwards of 22 inches or greater depending upon how many perforators are incorporated into the skin paddle.
In the photo below, radiation has caused significant burn to the anterior chest leaving an open wound with exposed bone. Adequate treatment of this requires wide surgical debridement of devitalized tissue and closure with vascularized tissue. The latissimus dorsi myocutaneous flap was chosen.

The flap was marked on the posterior chest wall with demensions of 10 x 22 inches. The left of the photo marks the scapula with the right marking the iliac crest.

Dissection of the latissumus dorsi is best commenced anteriorly at the free border. Perforators are carefully coagulated as one dissects posteriorly. The muscle is then disinserted from its inferior origin along the iliac crest. The dissection around the scapula can be difficult. Thus, I find it easier to proceed from a superior to inferior direction by elevating the superior border of the muscle with double hooks and then proceeding inferiorly towards the scapula tip.

The serratus branch is then suture ligated and the pedicle is then followed proximally toward the axillae until the thoracodorsal artery and vein are identified.

The vascular leash on the latissimus is then checked to see if the muscle can be rotated freely anteriorly towards the chest wall.

A z-plasty can be completed across the axillae to allow free rotation anteriorly towards the anterior chest.

The latissimus dorsi muscle and skin paddle can extend across the midline in anterior chest wall defects.

The flap is then inset and closed over closed suction drains.