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Latissimus Dorsi Muscle Harvest

  • Jarosław Kużdżał
    Correspondence
    Address reprint requests to Jarosław Kużdżał, MD, PhD, FETCS, Department of Thoracic Surgery, John Paul II Hospital, Jagiellonian University Collegium Medicum, Cracow, Poland.
    Affiliations
    Department of Thoracic Surgery, Jagiellonian University Collegium Medicum, John Paul II Hospital, Cracow, Poland
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Open ArchivePublished:March 07, 2018DOI:https://doi.org/10.1053/j.optechstcvs.2018.02.005
      Muscle flaps have multiple applications in thoracic surgery. Among the available flaps, the latissimus dorsi muscle flap is of special interest because of its unique characteristics, such as its large volume, making it suitable for filling pleural spaces, its constant pattern of vascular supply, and its wide arch of rotation, enabling transposition to different regional sites in the chest, back, and neck, thus eliminating the need for vascular microanastomosis in virtually all applications within the chest. Also, after division of the dominant vascular pedicle, the latissimus dorsi can be prepared as an inverted flap and used for reconstruction of the diaphragm. The latissimus dorsi muscle flap is useful for myoplasty of infected pleural spaces and bronchial fistulas, as well as for reconstruction of large soft tissue defects. The latissimus dorsi can be used either as a simple muscle flap or as a musculocutaneous flap. It is well suited to be used locally but also as a free flap with microvascular anastomosis in remote areas of the body. This paper presents the technique of harvesting the latissimus dorsi muscle flap and provides clues for its effective application in different clinical scenarios.

      Keywords

      The latissimus dorsi flap was described as early as 1906 by Italian surgeon Iginio Tansini,
      • Tansini I.
      Scritti medici.
      but this technique was abandoned at that time and was not widely used until the 1970s.
      • Olivari N.
      The latissimus flap.
      • Schneider W.J.
      • Hill H.L.
      • Brown R.G.
      Latissimus dorsi myocutaneous flap for breast reconstruction.
      The latissimus dorsi muscle plays an important role in thoracic and reconstructive surgery. It is useful for myoplasty of infected pleural spaces and bronchial fistulas, as well as for reconstruction of large soft tissue defects. The latissimus dorsi can be used either as a simple muscle flap or as a musculocutaneous flap (the latter is not described here). This muscle is well suited to be used locally but also as a free flap with microvascular anastomosis in remote areas of the body because of its following anatomical characteristics: (1) large volume, which makes it suitable for filling pleural spaces; (2) a constant pattern of vascular supply; (3) a wide arc of rotation, enabling transposition to different regional sites in the chest, back, and neck; and (4) absence of avascular microanastomoses.
      In this paper, only the fundamental topics related to harvesting the latissimus dorsi are discussed, these being of practical importance for thoracic surgeons (Figure 1, Figure 2, Figure 3, Figure 4, Figure 5, Figure 6, Figure 7, Figure 8, Figure 9, Figure 10, Figure 11, Figure 12). Harvesting of the latissimus dorsi musculocutaneous flap is not discussed here. Similarly, more advanced techniques, for example, enlarged, split, or extended flaps, as well as the thoracodorsal artery perforator flap and the osteomusculocutaneous flaps, which are the domain of reconstructive surgeons, are beyond the scope of this text.
      Figure 1
      Figure 1The latissimus dorsi is a large, flat muscle covering most of the lower part of the back. Except for its superior-medial portion, covered by the trapezius muscle, it is located superficially, just below the dorsal fascia. The attachment of its proximal tendon, which is a wide aponeurosis called thoracolumbar fascia, extends from the spinous processes of the vertebrae Th 6-L5 and the median sacral crest to the outer lip of the iliac crest. From these attachments, the fibers of the latissimus dorsi muscle converge toward the axilla, where they form a flat tendon. This tendon runs anteriorly and around to the tendon of the teres major muscle and attaches to the lesser tubercle of the humerus.
      Figure 2
      Figure 2The latissimus dorsi is a typical class V muscle according to the Mathes-Nahai classification, with 1 dominant pedicle and paraspinal perforating branches from the 9th to the 11th intercostal arteries and from the 1st to the 3rd lumbar arteries. All these vessels form a network of interconnecting branches, so the muscle is able to survive if either the dominant pedicle or the perforating vessels are divided.
      Figure 3
      Figure 3The dominant pedicle is based on the thoracodorsal vessels. The thoracodorsal artery is 1 of the 2 end-branches of the subscapular artery. The subscapular artery originates from the axillary artery close to the lateral border of the scapula, runs downward, and, after a short (~ 3 cm) course, divides into the 2 end-branches: the circumflex scapular artery that runs posteriorly and the thoracodorsal artery. The thoracodorsal artery runs caudally, gives 1-3 branches to the upper part of the serratus anterior muscle, and enters the latissimus dorsi muscle from the deep side, close to its posterior border. This artery usually divides into the descending and the horizontal branches. A detailed description of the vascular supply of the latissimus dorsi muscle has been published by Rowsell et al.
      • Rowsell A.R.
      • Davies D.M.
      • Eisenberg N.
      • et al.
      The anatomy of the subscapular-thoracodorsal arterial system: Study of 100 cadaver dissections.
      Figure 4
      Figure 4The standard thoracotomy incision along the sixth rib provides an excellent approach for harvesting of the latissimus dorsi muscle. However, if the musculocutaneous flap (not presented here) is planned, the incision around the skin island is sufficient for muscle dissection. The skin incision is extended through the fatty tissue down to the level of the dorsal fascia. Further dissection is performed along the fascia, leaving it intact on the muscle. The dissection starts with an elevation of the inferior cutaneous flap. Initially, a sharp skin retractor is convenient, but as the dissection of the skin flaps progresses, long liver retractors are more useful. Countertraction with the left hand is helpful as it pulls the muscle upward, bringing the soft attachments of the fascia closer and facilitating their division with cautery.
      Figure 5
      Figure 5Incision of the fascial layers along the anterior and the posterior borders of the latissimus dorsi muscle and blunt dissection behind the muscle are performed. This maneuver enables retraction of the muscle upward, facilitating its dissection toward the thoracodorsal fascia and the attachments to the spine and the iliac crest. Because often acquiring the largest possible volume of muscle is important, it is crucial to dissect the muscle as deep toward its proximal attachments as possible. As the entire lower part of the muscle is mobilized, its medial and lower attachments are divided with cautery.
      Figure 6
      Figure 6With the inferior part of the latissimus dorsi mobilized, it is turned over to expose its deep surface. It is convenient to hold it up with 2 Allis clamps or, alternatively, with 2 stay sutures. Loose, soft connective tissue between the latissimus dorsi muscle and the underlying serratus anterior muscle is divided, with care, so that the branches of the thoracodorsal artery that run on the lower surface of the muscle are not injured. Usually, at the level of the fifth rib, a major horizontal branch is encountered, running anterior to the serratus anterior muscle. This branch should be ligated close to its origin, but caution should be exercised in order not to divide the branch running caudally supplying the inferior part of the latissimus dorsi muscle.
      Figure 7
      Figure 7Further dissection is continued cranially. The superior skin flap is dissected along the fascia covering the latissimus dorsi muscle. The dissection plane should be kept strictly on the muscle's anterior surface to avoid injury to the vascular pedicle. A long liver retractor is useful to elevate the skin flap as the dissection approaches the axilla. Again, gentle retraction of the muscle downward facilitates division of the loose connective tissue along the fascia.
      Figure 8
      Figure 8Alternately with dissection of the anterior surface, dissection of the inferior surface of the muscle is continued. As the superior aspect of the muscle is approached, great caution should be exercised. This should be the most cautious part of the procedure, because inadvertent injury to the thoracodorsal artery would preclude the use of the latissimus dorsi flap. Vigilant step-by-step dissection using a curved dissector and fine scissors may be the safest way to identify the thoracodorsal artery and to dissect it.
      Figure 9
      Figure 9Above the point where the thoracodorsal artery enters the latissimus dorsi, the muscle fibers converge to a narrow tendon that runs toward its insertion on the lesser tubercle of the humerus. The part of the muscle above the entry point of the vascular pedicle is 8-10 cm long, but there is no need to dissect it entirely, as it does not add to the volume of the flap. It should be transected 2-3 cm above the vascular pedicle. Just to be on the safe side, it is good to encircle this narrow part of the muscle with the thumb and the index of the left hand, which provide protection for the vascular pedicle during tendon transection. It is important to keep in mind that once the tendon is transected, the only attachment of the latissimus dorsi muscle is its vascular pedicle. From then on, extreme caution should be exercised to avoid any strain on, or kinking of, the pedicle.
      Figure 10
      Figure 10Because of its length and the dominant vascular pedicle, the latissimus dorsi flap has a wide arch of rotation (dashed lines). As a pedicled flap, it can reach any part of the ipsilateral chest both on its anterior (A) and posterior (B) surface. On the other hand, its large volume makes it optimal for filling infected spaces inside the chest. For the latter application, the flap is introduced to the chest through the bed of the resected part of the third rib. As soon as the flap is placed in its final position, its margins are sutured to the borders of the opening in the chest wall to avoid any tension on the vascular pedicle. The pedicle should be kept in sight during placement of these sutures to prevent its inadvertent suture ligation.
      Figure 11
      Figure 11The free latissimus dorsi flap. If a free muscle flap is planned, the dissection of the vascular pedicle should be continued up to its origin. The thoracodorsal artery is 6-12 cm long and runs cranially to the anterior border of the scapula. It should be kept in mind that in 75% of patients, between its origin and the entrance point to the latissimus dorsi muscle, the thoracodorsal artery gives 1-3 branches to the serratus anterior muscle.
      • German G.
      • Öhlbauer M.
      Latissimus dorsi flap.
      These branches should be clipped and divided. To minimize the ischemia time, the donor site should be prepared first and the dissection of the latissimus dorsi flap should be completed before the vascular pedicle is divided. The thoracodorsal vessels are ligated separately, close to their origin, clipped distally, and divided.
      Figure 12
      Figure 12The reverse latissimus dorsi flap. The reverse latissimus dorsi flap is used for myoplasties of infected spaces located in the lower part of the pleural cavity and for reconstruction of the diaphragm, particularly in an infected field. The skin incision should be located along the eighth rib. Dissection starts on the anterior surface of the latissimus dorsi muscle, as presented in Figure 4, Figure 5. However, the next step is dissection of the distal portion of the muscle. It generally follows the same principles as presented in Figure 7, Figure 8, Figure 9, with 2 exceptions. The first is that the thoracodorsal vessels are ligated and divided at the point they enter the latissimus dorsi muscle, and the second is dissection of the distal part of the muscle as close as possible to its insertion to the humerus. As the distal tendon is divided, the muscle is turned inside out, and dissection of its deep surface is commenced. For sufficient mobilization, the 2 uppermost perforating branches usually need to be divided, but caution should be exercised avoiding devascularization of the muscle more than necessary. For reconstruction of the diaphragm, a segment of the 9th or 10th rib is usually resected to provide an opening for the introduction of the muscle into the chest. A properly mobilized latissimus dorsi flap enables reconstruction of the entire hemidiaphragm.
      • Bedini A.V.
      • Andreani S.M.
      • Muscolino G.
      Latissimus dorsi reverse flap to substitute the diaphragm after extrapleural pneumonectomy.
      If the muscle is used for myoplasty of the infected intrathoracic space, the chest wall defect is positioned according to the location of the space to be filled. A particular concern is the use of the inverted latissimus dorsi flap after extrapleural pneumonectomy. Generally, its use is not recommended for primary diaphragmatic reconstruction. In this setting, the denervated muscle loses its tone, resulting in high elevation of the reconstructed diaphragm because of the intraabdominal pressure. The elevated position of the liver and other viscera makes it difficult for radiation oncologists to plan appropriate radiation fields for adjuvant radiotherapy. If synthetic graft infection occurs after extrapleural pneumonectomy or pleurectomy-decortication, the inverted latissimus dorsi flap is generally not an option, as it is routinely transected during the original approach. However, if planned use of the muscle is anticipated during the primary surgery, the latissimus dorsi can be transected close to its humeral attachment, instead of along the sixth or the seventh rib. This modification does not preclude the use of the inverted latissimus dorsi flap for diaphragmatic reconstruction in the future.

      Wound Closure

      The bed of the dissected latissimus dorsi muscle is drained using single Redon tube No. 14 or 16. The tube should be positioned in the inferoposterior part of the bed to facilitate removal of the exudate. The wound is closed with continuous sutures in the subcutaneous and the cutaneous layers. Occasionally, seroma formation is observed after removal of the Redon drain, which is managed with repeated needle aspiration and compressive wound dressing.

      References

        • Tansini I.
        Scritti medici.
        (Italy, Milan: Wasserman)1935
        • Olivari N.
        The latissimus flap.
        Br J Plast Surg. 1976; 29: 126-128
        • Schneider W.J.
        • Hill H.L.
        • Brown R.G.
        Latissimus dorsi myocutaneous flap for breast reconstruction.
        Br J Plast Surg. 1977; 30: 277-281
        • Rowsell A.R.
        • Davies D.M.
        • Eisenberg N.
        • et al.
        The anatomy of the subscapular-thoracodorsal arterial system: Study of 100 cadaver dissections.
        Br J Plast Surg. 1984; 37: 574-576
        • German G.
        • Öhlbauer M.
        Latissimus dorsi flap.
        in: Wei F. Mardini S. Flaps and Reconstructive Surgery. Elsevier, 2009: 287
        • Bedini A.V.
        • Andreani S.M.
        • Muscolino G.
        Latissimus dorsi reverse flap to substitute the diaphragm after extrapleural pneumonectomy.
        Ann Thorac Surg. 2000; 69: 986-988