16: Latissimus dorsi myocutaneous flap

Chapter 16
Latissimus dorsi myocutaneous flap

Introduction

The latissimus dorsi flap was first described by Tansini in 1896.1,2 The latissimus dorsi myocutaneous flap is one of the most commonly used free flaps in microvascular reconstructive surgery. It’s used primarily for the repair of breasts and extremity defects. The use of this flap in the head and neck is also commonplace as a microvascular transfer, especially in cases where a large volume of muscle or skin is needed. The scalp is probably the most common site in the head and neck region where the latissimus dorsi flap is utilized. Although most surgeons think of the utility of this flap as a free flap only, it can also have significant utility to the head and neck surgeon as a pedicled flap. The first description of its use as a pedicled flap in head and neck reconstruction was by Quillen et al. in 1978.3 Typically the use of the pedicled latissimus dorsi flap for the reconstruction of head and neck defects are for those selected cases where the neck is vessel depleted and the pectoralis major muscle has already been used before or is somehow compromised.

The latissimus flap can reach a number of areas in the head and neck when used as a pedicle flap. The flap can be used for defect located as high as orbital exenteration defects, temporal bone defects, as well as for pharyngeal reconstruction as in cases of laryngo-pharyngectomy resections.

The main concern for this flap is the potential for venous congestion and loss of the skin paddle. This result is often due to compression or kinking of the vascular pedicle in the axilla or as it travels in the tunnel to reach the defect.

Although the use of the latissimus dorsi muscle as a pedicle flap for head and neck may not be the first or second option for most reconstructive surgeons, it should be considered as a “bailout” option to the surgeon and for the very difficult cases stated earlier.

Anatomy

The latissimus dorsi muscle is a broad fan-shaped muscle with its origin from the lower six thoracic vertebrae as well as the fascia from the iliac crest and the lower four ribs. The muscle inserts into the medial aspect of the humerus.

The vascular supply to the latissimus muscle is from the thoracodorsal artery and vein. The thoracodorsal artery is a branch of the subscapular artery and the same is true for the vein.

The action of the latissimus flap is to aid in the adduction and inward rotation of the arm.

Flap harvest

The flap can be harvested with the patient in the prone position, supine position or most commonly, the lateral decubitus position.

Once the patient is intubated on the operating room table, the patient is placed in a lateral decubitus position and secured with the aid of a bean bag and straps. The position of the bean bag should allow for exposure of the spine and inferiorly to the iliac crest. A gel roll should be placed under the contralateral axilla in order to minimize pressure to the brachial plexus. The ipsilateral arm should be prepped and included placed in the operating field. The patient should be secured to the operating table with at least two straps. The area to be prepped should include the head and neck extending inferiorly to the ipsilateral anterior chest and back up to the spine. Inferiorly, the prep should end at the iliac crest. The bed is rotated towards the donor side so the patient is in a more horizontal position to allow for the ablative portion of the surgery. Once the resection is completed, the patient is then once again rotated to the opposite side, this time to allow for the harvest of the flap. The prepped arm can be positioned away from the operative field by the assistant and manipulated as needed during the harvest and transfer of the flap.

  • The anterior edge of the latissimus dorsi muscle is palpated and marked from the axilla extending caudally towards the insertion along the iliac crest.
  • The desired shape of the skin paddle is marked. Care should be taken to place the skin paddle well over the underlying muscle.
  • The skin incision is made along the anterior marked edge of the skin paddle and extended both towards the axilla superiorly and towards the iliac crest inferiorly.
  • The incision is extended to the fascia over the latissimus. A suprafascial dissection is then extended in the same way as the skin incision. The dissection is completed when the whole length of the anterior border of the latissimus muscle is well delineated.
  • At this point, the location of the skin paddle over the muscle is confirmed and, once deemed to be in the correct location, the remainder of the skin paddle is incised and extended to the fascia of the latissimus.
  • The skin paddle is sutured to the muscle fascia to prevent shearing of the skin from the muscle during the remainder of the flap elevation as well as during the muscle transfer.
  • The anterior edge of the latissimus muscle is elevated and the plane between the latissimus muscle and the serratus anterior muscle is dissected.
  • The plane under the latissimus muscle should be relatively avascular. The dissection towards the axilla should be done carefully to identify the thoracodorsal artery and its accompanying venae commitantes. The insertion of the vascular pedicle is approximately 12 cm inferior from the muscle insertion to the humerus.
  • The inferior portion of the flap (inferior to the skin paddle in cases of a musculocutaneous flap) at the desired muscle length is separated and dissection is extended in a cephalad direction and medially along the vertebral column.
  • Once the desired muscle length is harvested along the medial aspect of the skin island, the dissection is then devoted to the vascular pedicle.
  • The thoracodorsal vessels are dissected towards the subscapular vessels. Care is taken to identify and protect the long thoracic nerve.
  • Once the vessels are dissected, the muscle is divided superior to the insertion of the vascular pedicle in the undersurface of the muscle.
  • With the flap mobilized, the vascular pedicle should be checked to avoid any twisting or kinking.

Creation of the tunnel

  • The tunnel in the neck should be made in the subplatysma plane. Care should be taken not injure the external jugular vein when developing the neck tunnel. The dissection is continued until the clavicle is reached and extended above the clavicle.
  • Once the tunnel reaches the clavicle, attention is then turned to the development of the axillary tunnel.
  • Using the incision from the flap harvest, dissection is extended in the axilla towards the lateral aspect of the pectoralis major muscle. Once the pectoralis major muscle is identified, the pectoralis minor is identified under the pectoralis major. A tunnel can be developed either above or below the pectoralis major muscle. If the tunnel is above the muscle it will result in a slight loss of the pedicle length as it travels to the neck.
  • If the tunnel is developed between the pectoralis muscles, the path to the neck will have to be developed by making a skin incision below the clavicle and incision of the pectoralis muscle insertion along the clavicle to allow for the flap transfer. The tunnel should be wide enough to accommodate the flap without constriction.

Transfer of the flap to the neck

  • The flap is ready to transfer to the recipient site in the head and neck once the tunnel is completed.
  • A large clamp is introduced from the subclavicular incision and advanced in the tunnel towards the axilla. Using large retractors, the axillary tunnel is elevated and the inferior portion of the flap is turned towards the clamp and the muscle is clamped.
  • The flap is mobilized to the neck by a combination of pulling from the neck and pushing from the axilla with care to not shear the skin paddle.
  • Once the flap is transferred to the neck in the subplatysma tunnel, the path of the/>
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Jan 12, 2015 | Posted by in Oral and Maxillofacial Surgery | Comments Off on 16: Latissimus dorsi myocutaneous flap

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