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Resurfacing shallow defects of extremities with an appropriately thin flap is a common but difficult task. This can be accomplished by harvesting the thoracodorsal artery perforator flap from the lateral aspect of the upper back. This flap can be based on the musculocutaneous perforator, which usually emerges in an area ~8 to 10 cm below the posterior axillary fold and 2 to 3 cm posterior to the lateral border of the latissimus dorsi muscle, or the septocutaneous perforator of the thoracodorsal artery, which emerges anterior to the lateral border of the latissimus dorsi muscle. Between February 2001 and May 2005, we used the thoracodorsal artery perforator flap for extremity reconstruction in 18 clinical cases. The existing soft tissue defects among all patients resulted from trauma, scar release, chronic ulcer, and tumor ablation. The main advantages of the thoracodorsal artery perforator flap are that it only requires cutaneous tissue to achieve better accuracy in reconstructive site and it minimizes the donor-site morbidity by preserving the function of the latissimus dorsi muscle and hiding the prominent scar of the donor region. However, searching for a reliable perforator and the tedious process of intramuscular retrograde dissection of the perforator are time-consuming and skill-demanding.
The loss of soft tissue at the distal limb, with the exposure of tendon or bone, represents a challenging reconstructive problem because of the thin skin structure and lack of locally available tissue. Although the latissimus dorsi musculocutaneous flap is one of the most reliable flaps in reconstructive surgery, the bulkiness and donor defects of the flap often preclude its use for resurfacing shallow defect of distal limb. Covering a tissue defect, especially on the hand or foot, requires a relatively thin flap to provide the reconstructive site with aesthetic and functional refinement in a single stage. Since Angrigiani et al1 described the concept of the thoracodorsal artery perforator flap, the harvesting technique of the latissimus dorsi musculocutaneous flap has been modified to exclude the muscle portion and to raise the cutaneous part only, based upon a single perforator of the thoracodorsal artery. This flap reduces the morbidity at the donor site and provides a suitable thickness for resurfacing. We have used the thoracodorsal artery perforator flap to treat 18 patients and the experience obtained from the management of these cases has formed the basis of this report.
Between February 2001 and May 2005, the thoracodoral artery perforator flap was used for resurfacing shallow defects over the distal limbs after release of scar contracture, trauma, chronic ulcer, and tumor ablation. For all patients, grafting was contraindicated due to the exposure of tendons and/or bones at the wound site. The patients included 12 men and six women, ranging in age from 20 to 70 years. Five recipient sites were located on the hands, two on the forearms, four on the legs, and seven on the feet.
After general anesthesia is administered, the patient is placed in a lateral decubitus position and the contralateral back is usually selected for the donor tissue. A marking line is drawn from the posterior axillary fold to the posterior superior iliac spine. This line demarcates the lateral border of the latissimus dorsi muscle. Generally, the reliable perforator can be identified along the lateral border of the muscle with the assistance of Doppler ultrasound. The musculocutaneous perforator is usually located 8 to 10 cm below the posterior axillary fold and 2 to 3 cm posterior to the lateral border of the latissimus dorsi muscle. The septocutaneous perforator usually emerges at the same level of the musculocutaneous perforator, but anterior to the lateral border of the latissimus dorsi muscle. The audible perforator is placed on the proximal third of the flap to increase effective pedicle length, and the anterior edge of the flap is designed anterior to the lateral border of the latissimus dorsi muscle to secure the septocutaneous perforator detection.
With the aid of loupe magnification, the anterior edge of the flap is incised first through the skin and subcutaneous tissue to the underlying fascia. From this stage, the flap is carefully elevated and detached from the underlying fascia, because the perforator may be slender and can easily be missed as fibers of the fascia under flap traction may be divided in accident.
As the reliable musculocutaneous perforator is encountered, the next step involves the intramuscular retrograde dissection of the perforator, following which any attached muscular branches should be cautiously clipped or cauterized using bipolar electrocauterization. Leaving several strips of muscle fiber attached to the pedicle allows safe dissection and prevents kinking or undue tension of the perforator during flap inset. As the reliable septocutaneous perforator is selected, the proximal dissection along the perforator to the thoracodorsal vessel is made between the latissimus dorsi and serratus anterior muscles. Once adequate pedicle length and suitable caliber of the thoracodorsal artery have been achieved, the posterior margin of the flap is incised and the flap is further detached from the muscle. No latissimus dorsi muscle is included in this flap, and the motor nerve to the latissimus dorsi muscle is also preserved. The width of skin paddle should not exceed 10 cm to allow reliable direct skin closure of donor site under moderate tension because of the remaining bulky latissimus dorsi muscle.
The thoracodoral artery perforator flap based on the musculocutaneous perforator was used in 15 patients, and the perforator flap based on the septocutaneous perforator was used in three patients. The size of the flap ranged from 5×3 to 17×9 cm. All flaps were safely raised with a single perforator and the donor defects were closed primarily. One flap developed venous congestion during the postoperative course and eventually partial necrosis.
A 20-year-old man sustained open fractures of the left distal tibia and fibula in a motor vehicle accident. After debridement and internal fixation of the fractured bones, there was a large soft tissue loss with exposure of tendons and bones over the anterior aspect of the left ankle. A free thoracodorsal artery perforator flap, 17×9 cm in size, was harvested from his right lateral back and based upon the musculocutaneous perforator, which emerged at 10 cm below posterior axillary fold and 3 cm posterior to the lateral border of the latissimus dorsi muscle. The pedicle was anastomosed to the anterior tibial vessels. The thin flap was completely viable following surgery, and the contour of the ankle was restored (Fig. 1).
A 40-year-old man suffered a crushing injury to the left big toe, with osteomyelitis of the proximal phalanx and necrosis of the overlying soft tissue. Following removal of infected bone and replacement of bony graft, a thin free thoracodorsal artery perforator flap, 5×3 cm in size, was raised and based on the musculocutaneous perforator. The pedicle was anastomosed to the dorsalis pedis artery and dorsal vein. The flap was completely viable and the contour of the big toe was restored (Fig. 2).
A 28-year-old woman had an enlarged neurofibroma of the right ankle. Following tumor ablation, a free thoracodorsal artery perforator flap, 12×8 cm in size, was harvested from her left lateral back for resurfacing the exposed bone and tendon. The flap was based on the musculocutaneous perforator and the pedicle was anastomosed to the posterior tibial vessels. The postoperative course was smooth and the flap survived well (Fig. 3).
A 21-year-old man experienced a painful scar with flexion contracture over the volar aspect of the right elbow. Following scar excision, a free thoracodorsal artery perforator flap, 13×8 cm in size, was raised to resurface the defect. The flap was based on the septocutaneous perforator, which emerged between the latissimus dorsi and the serratus anterior muscles. The pedicle was anastomosed to the radial artery and the cephalic vein of the distal forearm. The donor region was closed primarily and was hidden well in clothes. The postoperative course was uneventful. Full extension and good contour of the right elbow were obtained (Fig. 4).
Following injury, a 50-year-old man developed a painful scar with underlying flexor tendons adhesion on the right palm. Following scar excision and tenolysis of the flexor tendons, a free thoracodorsal artery perforator flap, 12.5×8 cm in size, was harvested from his left lateral back and based upon the musculocutaneous perforator. The pedicle was anastomosed to the radial vessels. The thin flap was completely viable following surgery, and the contour of the palm was restored (Fig. 5).
With the introduction of the concept of the perforator flap,2,3 muscle as a carrier for skin flap vascularity is no longer needed. The flap dissection avoids unnecessary bulk and preserves donor-site muscle function. Perforator flaps from the extremity4,5,6 and back1,7,8,9,10,11 can be made thin and, therefore, are useful for resurfacing shallow defects of distal limbs. Under these circumstances, the surgeon is required not only to cover an existing tissue defect but also to obtain a good quality and a natural appearance of the reconstructive site. On the basis of this same principle, a thin cutaneous flap from the upper back, supplied by the musculocutaneous perforator or the septocutaneous perforator of the thoracodorsal artery, was explored in this project.
The thoracodorsal artery arises from the subscapular artery and enters the deep surface of the latissimus dorsi muscle. It bifurcates with the upper branch running horizontally across the upper muscle and the lateral branch parallel to and ~2 cm from the lateral border of the muscle running toward the iliac crest. A predictable row of musculocutaneous perforators arise from the lateral branch of the thoracodorsal artery.1 The diameters of these musculocutaneous perforators appear to diminish distally. The proximal musculocutaneus perforator exits the muscle into the subcutaneous tissue ~8 to 10 cm below the posterior axillary fold and 2 to 3 cm posterior to the lateral border of the muscle. It measures 0.4 to 0.6 mm in diameter and is oriented obliquely from the deep surface to the superficial, appearing as a direct continuation of the thoracodorsal artery itself. The second musculocutaneous perforator, 0.2 to 0.5 mm in diameter, arises 2 to 4 cm distal to the origin of the first perforator. The first and second musculocutaneous perforators are present in most people. However, another perforator, the septocutaneous perforator of the thoracodorsal artery, is also found at the same level of the proximal musculocutaneous perforator and between the latissimus dorsi and the serratus anterior muscles near the lateral border of the latissimus dorsi muscle. Two perforator patterns have the same reliability as a pedicle of the thoracodorsal artery perforator flap.11
The thickness from skin to the deep fascia on the upper lateral back, 8 to 10 mm, is usually comparable to the distal limb. The pedicle length of the flap is controllable and a section of 10 cm in length is readily obtained. It is still uncertain what size perforator flap can be available based on a single perforator in the flank area. Kim11 demonstrated that a large flap, 20×15 cm in size, can be safely based upon a single musculocutaneous perforator and the flap dimension could be successfully expanded to 28×15 cm as a small portion of the latissimus dorsi muscle was included in the flap. The largest flap in our series was measured at 17×9 cm and was also based upon a single musculocutaneous perforator.
The free thoracodorsal artery perforator flap offers a long donor vessel that can reach the recipient vessel distant to traumatized or irradiated defects, homogeneous flap thinness that can be used for resurfacing shallow defects of extremities, a linear scar of the donor region that can be hidden well in clothes (a concern especially for women and children), and conservation of function in the latissimus dorsi muscle. The tedious dissection of perforators of varying diameters and locations, requiring prolonged surgery, is the main disadvantage of the thoracodorsal artery perforator flap.
Perforator flaps represent an important step forward in reconstructive plastic surgery. The main goal of the plastic surgeon facing a complex soft tissue defect is to replace “like with like” tissues at minimal donor-site cost and with maximal efficacy. The thoracodorsal artery perforator flap, which allows surgeons to accomplish this goal better, should serve as a valuable alternative to other types of fasciocutaneous flaps.