Latissimus Dorsi Flap Breast Reconstruction

Published on 09/05/2015 by admin

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CHAPTER 5 Latissimus Dorsi Flap Breast Reconstruction

James H. Boehmler, Charles E. Butler

Key Points

Latissimus dorsi (LD) myocutaneous flaps, first described by Tassini,¹ have been used in various reconstructive procedures for decades. In the setting of immediate or delayed breast reconstruction² LD flaps have several characteristics that can make them excellent options.

1. In part because of their vascular supply from the thoracodorsal vessels, LD flaps have reliable survival.

2. When used as pedicled flaps, LD flaps eliminate the need for microsurgery.

3. LD flaps can be customized, with variations that include full-muscle myocutaneous, split-muscle myocutaneous, muscle-only, and skin-and-fat-only flaps.

4. LD flaps are viable options for patients who have undergone radiotherapy.

5. LD flaps are good options for patients who are not candidates for abdominal flap-based reconstruction.

6. LD flaps can be used for chest wall coverage or as salvage therapy after a previous breast reconstruction has failed.

Patient Selection

Patients who have undergone radiotherapy can also benefit from the use of an LD flap in breast reconstruction. In these patients, the skin island of an LD flap can replace the constricted, irradiated skin of the breast; and the muscle of an LD flap can cover an implant, thereby decreasing the risk of capsular contracture and implant infection.³^–⁵ Patients who are at an increased risk of mastectomy skin flap necrosis, such as tobacco smokers, may also benefit from an LD flap, which can provide additional muscle coverage of a tissue expander or implant and a robust skin paddle. Furthermore, focal skin and soft tissue defects caused by previous partial mastectomy and radiotherapy that cannot be corrected with implants alone often can be repaired with an LD flap.⁶^,⁷

Indications

Every patient who desires breast reconstruction must undergo a thorough history and examination to help determine which reconstruction technique should be used. Specific details should be obtained regarding previous surgery to the abdomen, chest and axilla, previous history of radiation, and the patient’s preference for reconstruction method and willingness to undergo major surgery. Many reconstructive surgeons prefer abdominal flaps such as transverse rectus abdominis myocutaneous, deep inferior epigastric, or superficial inferior epigastric artery flaps for autologous tissue-based breast reconstruction. However, patients may not desire or have adequate tissue for an abdominal flap harvest. Furthermore, previous abdominal surgeries such as abdominoplasty, laparotomy, or liposuction may reduce the reliability of an abdominal flap or preclude abdominal flap-based breast reconstruction. In such cases, an LD flap offers a reliable alternative to an abdominal flap. In addition, if an implant is going to be included in the reconstruction, using an LD flap over the implant can improve the contour of the reconstructed breast,⁸ particularly in thin patients, in whom implant-based reconstructions tend to have less esthetic results (Table 5.1).

Table 5.1 Advantages and disadvantages of latissimus dorsi flap-based breast reconstruction compared to expander/implant-based reconstruction, and abdominal flap-based reconstruction

Operative Technique

Preoperative evaluation and markings

While the patient is awake and standing or sitting upright, the reconstructive surgeon uses a provocative maneuver to evaluate the contractility of the LD muscle (Fig. 5.1). The patient adducts her arm; as the LD muscle contracts, the reconstructive surgeon palpates and marks the muscle’s anterior border. The tip of the scapula, posterior iliac crest, and midline are also marked to further delineate the muscle’s topography (Fig. 5.2). If the patient has a history of lymph node sampling and the LD muscle does not contract when the patient adducts her arm, the thoracodorsal nerve may be injured or transected, and the adjacent thoracodorsal vascular pedicle may also be injured.

Fig. 5.1 Forced adduction of the shoulder enables palpation and marking of the latissimus dorsi muscle’s anterior border.

Fig. 5.2 Topography of the latissimus dorsi muscle. Key landmarks include the tip of the scapula, the iliac crest, the posterior midline, and the muscle’s anterior border.

If the breast reconstruction requires a skin island, the reconstructive surgeon can design and transpose a template of the size, shape, orientation, and location of the anticipated skin island onto the skin that overlies the LD muscle. The location of the anticipated skin paddle is critical in determining the relative location of the muscle and skin island in the reconstructed breast during inset. The template should also reflect the 90–110° of rotation the flap will undergo from the patient’s back to her chest during the reconstruction (Fig. 5.3). Attaching the template to a towel and using the axilla as a pivot point can help the surgeon confirm the flap will reach its intended final location. To ensure that the flap donor site can be closed primarily, the reconstructive surgeon should pinch together the anticipated incision lines. In most patients, primary closure without significant tension can be performed if the skin island is less than 10 cm wide. If a skin island is not required for breast reconstruction, the reconstructive surgeon can harvest the LD flap through a small incision in the posterior axilla and use endoscopy to limit the number of incisions made on the patient’s back.

Fig. 5.3 Preoperative markings for bilateral immediate breast reconstruction with latissimus dorsi myocutaneous flaps and tissue expanders after skin-sparing mastectomy. The skin paddle is designed to rotate easily into the mastectomy defect, taking into consideration that 90–110 degrees of rotation will occur.

Positioning

For unilateral breast reconstruction, an LD flap is commonly harvested and the donor site closed while the patient is in a lateral decubitus position. The patient who undergoes immediate breast reconstruction is usually in a supine position during mastectomy, and the reconstructive surgeon can confirm the integrity of the thoracodorsal vascular pedicle and start the anterior dissection of the LD flap from this approach; the patient can then be placed in the lateral decubitus position for flap harvest and donor site closure. Following donor site closure, the patient is then repositioned in the supine position for implant placement, flap inset, and breast symmetry and shape examination.

For bilateral breast reconstruction, LD flaps can be efficiently harvested while the patient is in the prone position; however, care must be taken to avoid direct pressure on the mastectomy skin flaps while the patient is prone. Judicious use of padding can prevent breast skin flap compression.

Flap elevation

Full-muscle myocutaneous flap elevation

If the patient has undergone axillary lymph node sampling, the reconstructive surgeon should identify the vascular pedicle anteriorly though the mastectomy defect while the patient is supine. Once the pedicle has been identified and preserved, the reconstructive surgeon should mobilize the flap as much as possible from the surrounding soft tissues (Box 5.1).

Box 5.1 Surgical steps in latissimus dorsi (LD) flap harvest

• Create a breast pocket in the chest and a superior tunnel into the axilla

• Identify and confirm the patency of the thoracodorsal pedicle from an anterior approach

• Dissect the thoracodorsal pedicle from surrounding soft tissue using an anterior approach

• Confirm skin paddle markings and simulate transposition

• Incise skin and bevel away from incision line through subcutaneous fat

• If harvesting an extended LD flap, elevate the flap just deep to Scarpa’s fascia

• If harvesting a standard LD flap, elevate the flap at the level of the muscle fascia

• Complete the superficial dissection up to the borders of the LD muscle

• Identify the anterior border of the LD flap superiorly and separate the LD muscle from the serratus anterior and external oblique muscles

• Elevate the LD muscle off the chest wall from the muscle’s anterior edge posteriorly

• Ligate all lumbar perforating vessels

• Divide the distal muscle from its inferior border

• Divide the medial muscle from the paraspinal fascia, taking care not to injure the fascia

• Separate the LD muscle superiorly from the trapezius and teres major muscles

• Identify the thoracodorsal pedicle on the deep surface of the LD muscle

• If necessary, circumferentially free the LD muscle proximal to the thoracodorsal pedicle and divide the insertion

• Identify and divide the thoracodorsal nerve

• Transpose the LD flap to the chest and anchor a portion of muscle in the anterior axilla to prevent traction injury to the vascular pedicle

• Place drains and close the donor site with quilting sutures

• Place the patient in the supine position

• Orient the LD muscle and skin paddle on the chest wall

• Suture the superior and medial aspects of the LD muscle into the edges of the breast pocket

• Place the expander or implant under the LD muscle

• Suture the remaining LD muscle around the expander or implant to provide complete muscle coverage

• Place drains in the breast pocket and irrigate with antibiotic solution

• Suture the skin paddle in place

• Apply sterile dressings

Figure 5.4 shows the dissection planes for the standard myocutaneous and extended myocutaneous LD flaps. To facilitate a smooth transition between the mastectomy skin and the skin island inset, the reconstructive surgeon incises the skin island at a slight outward angle through the subcutaneous fat. Sufficient subcutaneous fat is preserved at the edge of the donor site to prevent a depressed scar and/or fasciodesis. When harvesting an extended LD flap, the reconstructive surgeon creates a plane just deep to Scarpa’s fascia; the flap’s volume is increased by including a rim of deep fat below Scarpa’s fascia.⁹^,¹⁰ In contrast, when harvesting a standard LD myocutaneous flap, the reconstructive surgeon dissects directly down to the investing muscle fascia. Dissection over the LD muscle is continued to its peripheral margins. The anterior margin of the LD muscle is identified and separated from the serratus anterior muscle. Because the serratus and external oblique muscles coalesce with the LD muscle inferiorly and posteriorly, it is easier to identify the anterior border of the LD muscle cephalad and dissect the muscle from the chest wall caudally. Once the LD muscle’s anterior border is freed, the plane deep to the LD muscle is developed caudally to avoid injuring the vascular pedicle. The large lumbar and intercostal perforating vessels entering the posterior surface of the LD muscle are isolated and ligated.

Fig. 5.4 Dissection planes for the standard myocutaneous and extended myocutaneous latissimus dorsi flaps. The standard flap dissection plane bevels slightly away from the skin incision toward the deep investing fascia of the latissimus dorsi muscle. The extended flap dissection proceeds until the Scarpa’s fascia is identified; the flap is raised just deep to this fascia, leaving deep fat attached to the muscle for added soft-tissue bulk.

Using electrocautery or electrosurgical bipolar scissors, the inferior border of the LD muscle is divided. In a cephalad direction, the muscle is released from its medial fascial attachments and elevated off the chest wall. The underlying paraspinous fascia is not violated while the muscle is being detached from the posterior midline. The inferior lateral border of the overlying trapezius muscle is identified and preserved as medial dissection of the LD muscle progresses cephalad. Once the medial aspect of the LD muscle is freed, the muscle’s superior edge is separated from the trapezius muscle medially and from the teres major muscle laterally. If a deep fat pad is to be included with the LD flap, the teres major muscle is not raised with the flap.

Dissection of the LD muscle proceeds cephalad toward the neurovascular bundle, which enters the deep surface of the LD muscle 8–10 cm inferior to the axillary line and 2–3 cm lateral to the muscle’s anterior border. The anterior branch of the bundle that supplies the serratus anterior muscle group is identified and preserved unless it prevents adequate flap rotation. The pedicle dissected is typically 8–10 cm long, but complete dissection of the pedicle often is not necessary to allow for an adequate arc of rotation; therefore, pedicle dissection should proceed only to a point that enables adequate flap rotation without tension on the vascular pedicle (Fig. 5.5).

Fig. 5.5 Elevated bilateral myocutaneous latissimus dorsi flaps, prior to inset into the mastectomy defects.

The tendinous insertion into the humerus is exposed by dissecting cephalad and circumferentially near the LD insertion. The reconstructive surgeon can divide the insertion to increase the arc of rotation and reduce any axillary bulging that the rotated proximal muscle may cause.¹¹ If the insertion is completely divided, care must be taken to prevent traction injury to the vascular pedicle.

The thoracodorsal nerve is identified, isolated, and divided at the surgeon’s discretion. Dividing the thoracodorsal nerve helps prevent muscle contraction when the patient attempts arm adduction and extension. If the nerve remains undivided, muscle contraction may resolve as the muscle atrophies; however, continued muscle contraction may annoy the patient, and secondary division of the nerve is difficult.

Two large, closed-suction drains are placed in a dependent location in the donor site. Drains are typically left in place for 1–3 weeks and removed once the output decreases to fewer than 30 ml of drainage per 24 hours. Placing quilting or progressive tension sutures from the donor site skin flaps to the chest wall may decrease the amount of drainage and incidence of seroma formation by closing off the dead space left by flap dissection and preventing shear forces.¹³ Primary skin closure can be performed without significant tension in almost all cases in which the skin paddle is less than 10 cm wide (Fig. 5.6).

Fig. 5.6 Primary closure of the donor site usually can be achieved when the skin paddle is less than 10 cm wide. Pinching together the anticipated incision lines can help determine the amount of skin that can be removed.

Split LD flap elevation

A split (segmental) LD flap can be useful in reconstructions for partial mastectomy defects. The anatomical basis for splitting the LD muscle is well established.¹⁴^,¹⁵ The skin paddle is marked as in Figure 5.3 and incised, and the anterior border of the LD muscle is identified. The lateral descending branch of the thoracodorsal pedicle is identified on the undersurface of the muscle, and intramuscular dissection is performed medial to the lateral vascular pedicle. The remaining muscle’s vascular pedicle is sacrificed to allow for flap rotation; however, the muscle’s nerve branches are preserved to provide motor function.

Thoracodorsal artery perforator flap elevation

Like a split LD flap, a thoracodorsal artery perforator flap ¹⁵^–¹⁸ can be used to repair partial breast defects without compromising function of the remaining LD muscle. Preoperative ultrasonography or computed tomography angiography is usually used to help identify perforators on which to base the flap. The LD flap can be based on a row of perforators approximately 2 cm from the anterior margin of the flap just caudal to its scapular tip. Once the perforators are identified, a skin paddle is designed around the selected perforator. The skin island should be incised on only one side of the flap, preferably its anterior portion. Once the perforator is identified, the remainder of the skin island is elevated, and intramuscular dissection proceeds to the point at which the perforator meets with the thoracodorsal vascular pedicle. The LD muscle’s nerve branches are dissected from the vascular pedicle and preserved. All other vascular branches are divided until adequate pedicle length is attained. Great care must be taken to prevent traction injury to the perforators and vascular pedicle.

Flap insetting

A subcutaneous tunnel between the LD muscle donor site and the mastectomy defect should be created if one is not already present (Fig. 5.7). This tunnel is made as high in the axilla as possible while still allowing adequate flap insetting to help recreate the breast’s anterior axillary fold and prevent excessive tissue bulk in the axilla. When an implant is included, the reconstructive surgeon uses interrupted sutures to attach the edge of the LD muscle to the lateral chest wall and prevent migration of the implant into the axilla or donor site (Fig. 5.8). Securing the muscle to the chest wall laterally also helps prevent traction on the vascular pedicle, particularly if the muscle insertion has been transected.

Fig. 5.7 The subcutaneous tunnel for latissimus dorsi flap rotation should be made high in the axilla to better define the lateral border of the breast pocket and prevent the flap and/or implant from migrating into the axilla.

Fig. 5.8 The latissimus dorsi flap is brought to the chest through a high subcutaneous tunnel in the axilla. The proximal muscle is anchored with stitches to the lateral breast pocket to prevent traction injury to the thoracodorsal vascular pedicle.

Immediate reconstruction

The pectoralis major muscle is often maintained on the chest wall following mastectomy, and an implant can be placed above or beneath it. We prefer to elevate the pectoralis major muscle and place the implant beneath it to provide superior implant coverage and improve the contour transition from the chest wall to the implant along the superior pole of the reconstructed breast. In this case, the LD muscle is sutured ventral to the elevated pectoralis major muscle in a ‘pants-over-vest’ fashion (Fig. 5.9). The borders of the LD muscle are secured to the chest wall within the mastectomy pocket. Inserting the transected LD muscle into the pectoralis major tendon can improve the axillary contour of the reconstructed breast. As much of the flap inset as possible should be performed before placement of the expander or implant. Carefully insetting the LD muscle is important to correctly position the reconstructed breast and maximize symmetry between the reconstructed and contralateral breast. The LD flap inset must also allow the skin island to be appropriately located on the reconstructed breast to provide skin coverage within the mastectomy flap skin edges. If the LD flap is not large enough to fully cover the implant, the LD muscle can be sutured to the inferior border of the elevated pectoralis major muscle to create adequate submuscular space for the implant. Closed-suction drains are placed between the subcutaneous mastectomy skin flaps and LD muscle and within the submuscular pocket. The skin edges are trimmed to their final dimensions, and the skin island is fully inset (Fig. 5.10). Nipple and areola reconstruction are performed at a later stage (Figs 5.11 and 5.12).

Fig. 5.9 The latissimus muscle is inset to completely cover the implant.

Fig. 5.10 The skin edges of the flap are trimmed and inset only after the mastectomy flaps are trimmed back to viable tissue.

Fig. 5.11 A A preoperative photograph of a patient about to undergo bilateral skin-sparing mastectomies and immediate breast reconstruction. B The final postoperative appearance of the patient after reconstruction with latissimus dorsi flaps and implants and subsequent nipple and areola reconstruction and tattooing.

Fig. 5.12 A A preoperative photograph of a patient about to undergo immediate unilateral breast reconstruction with a latissimus dorsi flap and implant and contralateral breast augmentation. B Preoperative markings. C The patient after subsequent nipple reconstruction. She will eventually receive tattooing to color the areola.

Delayed reconstruction

When LD flap breast reconstruction is performed in a delayed setting, including after previous expander- or implant-based reconstruction, the pectoralis major muscle can either be left with the mastectomy flap or placed back on the chest wall depending on the amount of LD muscle available and the integrity of the mastectomy skin flaps. In patients with very thin mastectomy flaps or patients who have undergone radiotherapy or use tobacco, the pectoralis major muscle should remain attached to the mastectomy flap to help reduce mastectomy skin flap necrosis. In some patients, the subpectoral space is too tight for implant placement, and the mastectomy flap may need to be freed from the pectoralis major muscle. If the pectoralis major muscle remains attached to the mastectomy flap, the LD muscle is attached to the inferior edge of the pectoralis major muscle and then to the inframammary fold. The LD flap skin island is usually inset at the re-incised mastectomy scar. If there is lower pole skin deficiency or the inframammary fold is markedly elevated, the skin paddle can be inset into an inframammary incision. To ensure that the skin island and LD muscle are correctly oriented in the reconstructed breast, the reconstructive surgeon should plan the incision and skin paddle inset position and mark the patient prior to the start of the surgery.

Pitfalls and How to Correct

Seroma

The large potential space created during LD flap harvest can contribute to donor site seroma, the most common complication of LD flap-based breast reconstruction.^5,^8,^10,^13,¹⁹ Multiple long-term drains and quilting sutures can be used to prevent seromas.¹³ If a seroma develops after all surgical drains have been removed, serial aspirations are generally the initial treatment step, and frequently, the seroma will resolve quickly. If not, a new drain can be placed; often, this treatment can be supplemented with diluted fibrin sealant injections,²⁰ sclerotherapy,²¹ or steroid injections.²² Using compression garments or wrapping the donor site with elastic bandages is an important adjunct to all treatment options. If the seroma persists, surgical decortication of the seroma pseudocapsule²³ can be performed with the use of quilting sutures and closed-suction drains.