Historically, breast conservation therapy (BCT) was only performed when adequate tumor free margins could be obtained with cosmetically acceptable results. Although large tumor size alone is not considered a contraindication for breast conserving therapy in terms of local tumor control, it is an important variable in achieving optimal breast aesthetics (1). Breast parenchyma replacement techniques with muscle only latissimus flaps have extended the indications of breast conservation therapy in the modern day management of patients with breast cancer. Combining wide resection of the breast parenchyma with a muscle only flap reconstruction avoids the significant risk of local deformity thereby preserving aesthetics while increasing the accuracy of local disease control (2).

The critical factor in achieving an oncologically sound resection is tumor margin clearance (3). Surgical resection ultimately reaches a maximum volume limit when local glandular or dermoglandular rearrangements will not be adequate to achieve an aesthetically pleasing result, even if the contralateral breast is reduced for symmetry (4). In these cases, muscle only flaps can restore breast shape and contour while avoiding a contralateral breast procedure for symmetry. Muscle only flaps are being employed more frequently as the indications for breast conservation therapy are extended to include larger T2 and T3 breast tumors, including those treated with adjuvant chemotherapy and radiation (5).

The focus of this chapter is the latissimus muscle only flap used for autologous breast reconstruction of the partial mastectomy defect. Dr. Tansini first described the latissimus dorsi flap in 1897 for the coverage of a chest wall defect. For over a century, this flap has been utilized reliably in free and pedicle-based myocutaneous and myofascial flaps to cover soft tissue defects (6). The harvesting technique, which involves a large dorsal skin incision for flap elevation, has remained essentially the same since its introduction. Initial application of latissimus dorsi flaps involved coverage of soft tissue defects from a variety of anterior chest wall pathologies, ranging from bony malignancy to radical mastectomy (7). These early techniques, while clearly efficacious, were associated with a large harvesting incision, which can be troubling to a woman who is concerned with scarring and cosmesis. In an effort to decrease scarring, several authors have described a latissimus mini-flap, a procedure for filling in the breast defect which utilizes an incision running from the apex of the axilla along the lateral border of the breast towards the outer aspect of the inframammary fold (8,9,10,11). This innovative approach allows both wide local excisions in women who would otherwise have required a mastectomy as well as a more cosmetically appealing outcome. In an era of expanding indications for BCT and in an effort to even further reduce unwanted scarring, we harvest the latissimus dorsi muscle flap through an endoscopic approach, a procedure with even less scarring than the latissimus mini-flap.

In the early 1990s there was a surge in interest in endoscopic plastic surgery, primarily as an extension of the success of endoscopic cholecystectomy in general surgery (12,13,14,15). By comparison to other surgical disciplines, plastic surgery has been slower to adopt these rapidly growing techniques, in part due to the difficult anatomical exposures required for many reconstructive procedures (16). Unlike intra-abdominal or thoracic applications, reconstruction in plastic surgery frequently involves extensive soft tissue and neurovascular dissection within enclosed potential spaces (13,17). Limited surgical apertures and confined optical cavities have therefore inhibited the development and widespread usage of minimally invasive flap reconstruction techniques (18). Innovative ideas to optimize visualization within soft tissue planes have been described including external retraction with sutures, balloon dilation, CO₂ insufflation, and the use of additional ports (13,18,19,20). Improvements in general endoscopy in recent years and the addition of tumescent fluid has resulted in striking new advances in the technique of endoscopic latissimus harvest.

The use of endoscopes to assist in latissimus muscle harvest has been effectively used at our institution since 1994. The endoscopic-assisted reconstruction with latissimus dorsi (EARLi) flap technique, originally performed by the senior author after BCT, uses a much smaller axillary incision than the open back technique and is performed with the use of modified instruments used in endoscopic cholecystectomy surgery (21). Less traumatic tissue dissection in conjunction with a smaller surgical incision have enabled many patients to benefit from reduced postoperative pain, expedited recovery, and improved cosmesis (12). The principle aesthetic goals of the EARLi flap are to prevent breast deformity and maintain breast size and contour by replacing excised tissue volume. Preservation of aesthetics must be accomplished in conjunction with sound oncologic principles, namely complete surgical resection of the tumor, prevention of local recurrence and without interference of postoperative cancer surveillance.

Approximately two thirds of women with operable locoregional cancer are afforded the choice between BCT with lumpectomy, axillary lymph node sampling and breast irradiation, or
mastectomy with sentinel lymph node biopsy. Both treatment options have been shown to be medically equivalent with regard to overall survival rates (22,23,24). BCT focuses on optimizing cosmetic goals and minimizing the psychological morbidity of a mastectomy, while maintaining low rates of local recurrence. Completeness of tumor excision using wide margins are important in reducing local recurrence, however cosmesis and patient satisfaction after BCT is dependent on the volume excised (25). Significant volume loss after BCT surgery can result in a partial mastectomy defect requiring reconstruction with either volume displacement (local tissue rearrangement techniques) or volume replacement techniques, such as the latissimus dorsi flap.

Certain patients can be anticipated to have poor aesthetic outcomes after BCT. Recognizing these risk factors at the time of consultation can optimize surgical planning and reconstructive options. Patient risk factors include large tumor size, patients with small breast to tumor ratios and tumor position, specifically superior medial tumors and inferior lateral tumors (26). Although there is a trend toward managing larger breast tumors with BCT, one of the major limitations is the ability to perform a large enough resection without compromising the cosmetic result. If anticipated breast volume excised is greater than 10–20%, then reconstruction should be planned (25). Excising this amount of tissue in a small to medium breasted women without ptosis precludes the use of volume displacement techniques, whereas a latissimus flap reconstruction will provide optimal contour and shape. Treatment related risk factors include patients presenting with breast deformity following multiple re-excisions for positive margins or following the radiation phase of BCT. Delayed reconstruction after radiation treatment is best managed with a myocutaneous latissimus flap which will not only provide non-radiated supple skin but also provide additional blood supply for adequate wound healing in an irradiated operative field (27). This type of patient will therefore need a back incision for the skin requirement as opposed to a muscle only flap reconstruction.

Partial mastectomy defects reconstructed with local tissue rearrangements will usually require a contralateral breast symmetry procedure. Patients who are not amenable to surgery on the contralateral breast are good candidates for breast volume replacement with a latissimus flap. This indication for a muscle only flap achieves a good breast contour and shape while maintaining volume to match the symmetry of the opposite breast.

The EARLi technique is best suited for women requiring resection of 20 to 30% of their breast volume. It is optimal for defects in the upper outer quadrant, the site of occurrence for approximately 75% of breast cancers. The EARLi flap is least suited for breast defects in the lower inner quadrant, where less than 6% of breast cancers reside. A large cavity in the lower inner quadrant cannot be adequately filled with a pedicled latissimus flap.

The procedure has been used in patients with significant breast defects that compromise cosmesis, including those requiring quadrantectomy for large unicentric breast tumors, benign disease, or recurrent infection. Due to the reliable and robust blood supply of this flap, patients with comorbidities that would preclude transfer of other autologous tissues are considered safe candidates for pedicled latissimus dorsi reconstruction. We have used this flap safely in patients with diabetes, smokers and in obese patients.

General contraindications to muscle flap replacement techniques include patients with T4 tumors, multicentric disease, extensive malignant mammographic microcalcifications, inflammatory carcinoma and when clear margins cannot be assured without performing a mastectomy (28). The specific contraindications for an EARLi flap are essentially the same as those for a traditional latissimus dorsi flap. Lack of latissimus musculature to adequately fill the oncologic resection defect would compromise breast shape and fail to achieve aesthetically pleasing results. This may be overcome with the use of an implant or a contralateral breast reducing procedure if the patient is amenable. Pedicle compromise or division of the thoracodorsal vessels is a contraindication to the EARLi flap. A previous thoracotomy or axillary incision should raise the concern of an injured or ligated pedicle. The latissimus can survive on flow through the serratus branches if the thoracodorsal is the only vessel injured, but this would have to be carefully evaluated at the time of surgery. Other options for reconstruction would have to be discussed at the time of initial consultation in anticipation of previous injury to both arterial supplies.

A patient may present for consultation after completion of breast conservation therapy with a significant breast deformity. This type of secondary reconstruction for radiated partial mastectomy deformities can be more difficult to correct. The breast resection not only creates loss of volume, but the radiation results in soft tissue scarring and contracture, which may distort the nipple areola complex. These patients will often need a skin paddle in addition to soft tissues for volume replacement and therefore will not qualify for an endoscopic approach.

Because the latissimus muscle is transferred, muscle function may be compromised, but functional deficits are only seen with specific activities. This flap would have relative contraindications in women active in sports requiring extreme upper body strength such as mountain climbers, rowers and competitive swimmers (28).

To effectively care for breast cancer patients, the reconstructive surgeon must be able to visualize the anticipated defect, all of its reconstructive options and be able to treat all potential post operative complications. Discussing with patients their desires of having a symmetry procedure to the contralateral breast is necessary in the decision regarding reconstructive options. Volume replacement with the latissimus dorsi flap will be more suited to women who do not desire surgery to the opposite breast and who have large tumor to breast volume ratios. The location of the tumor plays a role in reconstructive options as medial lower quadrant defects in a patient with insufficient volume for local tissue rearrangement will not be a good candidate for latissimus dorsi flap reconstruction and would be better served with autologous tissue from the abdomen.