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The latissimus dorsi (LD) flap, based on the thoracodorsal vessels, has long been a mainstay of breast reconstruction after partial mastectomy. The LD flap is robust, reliable, can be harvested with or without a skin paddle, and the anatomy is well studied. Latissimus flaps are particularly helpful for lateral defects, superior defects and in small breasts, where local rearrangement is limited and even a relatively small-volume resection may result in distortion of the nipple position and loss of breast contour and volume. The flap has a more limited application in very medial defects due to
limitations of pedicle length in many patients.
Immediate repair of a BCT defect with the LD flap is technically easier, is associated with a lower complication rate, and potentially involves fewer operative steps compared with delayed repair.The difficulty with the immediate approach is that it is difficult to predict the degree of LD muscle atrophy and the impact of radiation therapy on breast volume and shape, which in turn makes it difficult to determine the degree of correction necessary. Most practitioners overcorrect the defect by 10–25% in an effort to compensate for LD muscle atrophy and the effects of radiation, but this approach is imprecise.
The donor site of the myocutaneous LD flap can be aesthetically problematic, especially if a significant amount of skin is needed for the breast. The anticipated location and extent of the scar as well as the longevity of postoperative drains to minimize seroma formation should be thoroughly vetted with the patient.
A muscle-only flap, transferred via endoscopic or endoscopic-assisted harvest, will provide a far more favorable donor site in terms of scar and seroma accumulation. Traditional LD myocutaneous flaps with or without skin sacrifice a functional muscle, and the impact of muscle harvest on shoulder function is not entirely clear.
Early reports suggested that there was little or no functional loss with muscle harvest, while some recent studies suggest a negative impact of LD muscle harvest on the activities of daily living in a certain proportion of patients. Accordingly, LD muscle sacrifice is not suggested in patients heavily reliant on their shoulder girdle strength, such as patients who have to use crutches.
Several modifications of the LD muscle flap have been proposed to minimize the functional impact on the donor site, including the ‘split’ LD flap described by Tobin and, more recently, LD ‘mini’ flaps. In these modifications, the LD muscle is split along the vascular axis utilizing either the descending (vertical) branch or the transverse (horizontal) branch of the thoracodorsal artery.
The most recent evolution of the LD flap is the thoracodorsal artery perforator (TAP) flap, in which no muscle or only a very small amount of muscle is harvested. The TAP flap is based on one of the two to three cutaneous perforators off the vertical thoracodorsal artery. The proximal perforator pierces the muscle and enters the subcutaneous tissue approximately 8 cm below the posterior axillary fold and 2–3 cm posterior to the lateral border of the muscle; a second perforator is usually present 2–4 cm distal to the first (Fig. 4.16).
The TAP flap represents the current evolution in reconstructive surgery Operative approach. Immediate repair of large skin and parenchymal defect with latissimus dorsi (LD) myocutaneous flap. The patient wished to maintain her nipple and her breast volume. The superior location of the lesion and the large size of the defect (30% of the breast) precluded adequate reconstruction without the introduction of well-vascularized tissue. Flap was overcorrected by approximately 20%. Patient is seen 10 months after the end of radiation therapy. Note the improved outcome and contour of the LD flap breast interface in this immediate reconstruction compared to the delayed attempts at repair. In addition to persistent seroma, the aesthetics of the back donor site may be a significant aesthetic consideration in a myocutaneous LD flap with a large skin paddle that is unfavorably located.