Master Techniques in Otolaryngology - Head and Neck Surgery: Reconstructive Surgery, 1ed.

10. Management of the Lateral Pharyngeal Defect: Pectoralis Major Myocutaneous Flap

Terance T. Tsue

INTRODUCTION

Defects in the lateral pharyngeal wall present challenges and difficulties for both the surgeon and the patient. The size of the defect and its location along the vertical and horizontal axis of the pharynx are obvious factors in reconstruction and rehabilitation. Unlike small and/or superficial defects that may be closed primarily or heal by second intention, larger and deeper defects and/or those associated with communication with the neck or exposure of bone and/or major vascular structures require more extensive planning and design. Defects in the superior aspect of the lateral pharynx, such as the nasopharynx, may present the surgeon with difficulties in both approach and exposure for the reconstruction, as opposed to a more inferiorly located lateral pharyngeal defect. Functional outcomes, such as the ability to swallow, speak, and/or breathe, are also a challenge for the patient, depending on the size and location of these lateral defects.

Nearly all defects in the lateral pharyngeal wall are the result of resection of cancer with the remaining few being the result of trauma, and benign tumors. In each case, careful evaluation and preoperative assessment of the defect are necessary in planning the appropriate reconstruction.

In 1979, Ariyan introduced the pedicled pectoralis major myocutaneous flap (PMMF) to head and neck reconstruction. The PMMF was a proven reliable myocutaneous flap for chest wall reconstructions, and it soon became the most popular flap for reconstruction of the head and neck. At the time, compared to microvascular free flaps, the PMMF was more reliable and easier to harvest and did not require expertise in microsurgical techniques. Compared with other contemporary pedicled flaps (e.g., temporal, forehead, deltopectoral (DP), trapezius, sternocleidomastoid, and tongue), the PMMF could be raised in one stage, had a longer arc of rotation, and had less donor site morbidity. With technical advances, better instrumentation, and improved postoperative monitoring, microvascular free flaps have played a more dominant role in head and neck reconstruction. While larger defects are best addressed with a free flap/microvascular reconstruction, there are still many defects in the lateral pharyngeal wall that may be successfully reconstructed with the pedicled PMMF. This is especially true in patients with (1) minimal ipsilateral recipient vasculature as is encountered in patients who have had a radical neck dissection, (2) significant medical comorbidities requiring minimized operative exposure and complexity, (3) severe peripheral vascular disease (PVD) obviating certain free tissue transfer donor sites, and (4) if carotid sheath coverage is concurrently desirable.

When considering the pectoralis donor site for pharyngeal reconstruction, I inquire about a history of shoulder dysfunction or chronic shoulder pain. Patients who relate a history of accessory nerve injury, scapular harvest/trauma, or rotator cuff injury are not ideal candidates for this donor site. A history of previous surgery or trauma in the area of the donor site must be sought.

The physical examination should be focused on the nature of the defect. Patch defects are ideal for this donor site. Circumferential defects and/or defects that involve the nasopharynx are difficult to manage with the pedicled pectoralis flap. The donor site should be inspected for signs of previous surgery or trauma.

I consider that the indications for reconstruction of the lateral pharynx defect with the PMMF are dependent on the site. The pectoralis flap is indicated for anterior lateral and/or posterior oropharynx. I find that defects of the nasopharynx are typically difficult to reconstruct with this donor site because it is difficult to reach this remote area from the donor site with a pedicled flap.

Relative contraindications for using the pectoralis flap include circumferential defects since the rate of fistula is exceptionally high in this situation. Surgical defects in the nasopharynx are also a contraindication. Previous trauma and surgery to the chest wall are also contraindications to the use of this flap.

As in any major reconstructive surgery, careful preparation sets the stage for success. Attention to operative risk assessment, pertinent preoperative imaging, and appropriate swallowing and airway precautions is paramount prior to planned reconstruction with a PMMF. A thorough examination of the head, neck, and chest is required before any decision or treatment plan is begun. Necessary in the assessment is the anticipated location of the defect in the lateral pharyngeal area and its relationship to vital vessels in the neck and the anatomy of the aerodigestive tract. Preoperative or planned CN XI sacrifice with trapezius dysfunction (i.e., concurrent radical neck dissection) and an ipsilateral PMMF harvest can yield some further low neck and shoulder girdle deformity and dysfunction, with subsequent displacement/dysfunction of the medial sternoclavicular joint. It is important to also document baseline speech, swallowing, breathing, and sensory function. The chest should be evaluated for evidence of previous surgery/trauma or congenital bone/muscle deformity that may obviate adequate maintenance of the PMMF vascular pedicle, limit flap adequate bulk, or compromise defect closure/healing. The length of the chest can also influence the arc of the rotation of the PMFF flap and limit its superior reach, although some of this is unpredictable and can only be determined intraoperatively.

Imaging is useful to adequately assess the involvement of the surrounding anatomic structures and the anticipated volume of tissue likely to be needed for reconstruction. Imaging is necessary to evaluate the potential spread of a lateral pharyngeal cancer to the skull base at the level of the nasopharynx, the base of the tongue at the oropharyngeal level, the larynx at the hypopharyngeal level, or the esophagus inferiorly. CT imaging with contrast is especially useful, to map the proximity and course of the vessels of the neck, as well as surrounding anatomy. It is also an excellent predictor of bone involvement should the lesion approach the mandible. MRI can be useful as an adjunct to assess the extent of involvement of the skull base, the base of the tongue, and major vessels. PET/CT is more helpful in defining metastatic cancer.

The role of endoscopy in the operating room setting cannot be underestimated in assisting the surgeon in evaluating the lateral pharyngeal defect, its location, and the feasibility of the planned approach. Direct laryngoscopy, esophagoscopy, and bimanual palpation under general anesthesia assist and confirm the choices made in the decision tree for resection and reconstruction. This is especially important in order to fully evaluate the nasopharynx and the apex of the pyriform sinus, since tumor involvement may not permit a moderate-size resection or laryngeal conservation.

Using this information and one’s clinical judgment, a reconstruction ladder or decision tree is used to determine the most ideal reconstruction technique for a given pharyngeal defect based on the information obtained in the preoperative and intraoperative assessment. The patient should be acquainted with the potential multiple reconstruction choices, since the intraoperative findings may require changing of best-laid plans.

Small and/or superficial defects may be closed primarily, heal by second intention, or possibly be reconstructed with a skin graft. Even some moderate-sized “concave” defects in the base of the tongue and/or tonsil fossa may be amenable to healing by second intention and wound contraction with only a small impact on form and function.

Other moderate-sized defects may include a portion of medial oropharyngeal structures with a portion of the lateral pharynx included. Flap reconstruction is often necessary to minimize tethering of the tongue laterally, which can impact speech and swallowing. Inferior moderate-size pharyngeal defects are assessed for potential impact on the larynx. Most inferiorly, defects with extension into the narrower tubed cervical esophagus may require a flap reconstruction that is more pliable than a pedicled pectoralis major flap.

Large defects in the oropharynx usually require flap reconstruction. The decision to use pedicled versus free tissue transfer is dependent on many factors. Some of those factors include (1) patient preference and medical condition, (2) expertise/experience of the surgeon, (3) availability of both donor flap sites and recipient bed vasculature, and (4) other concurrent reconstructive needs, such as the form and character of the reconstruction defect. Frequently, the pedicled PMMF and free tissue transfer are the main choices. I feel that there are several factors that influence the use of a pectoralis flap for reconstruction. These include the following:

1. Reconstruction defects where a bulkier and less pliable PMMF reconstruction does not impact pharyngeal function (i.e., concurrent laryngectomy).

2. Patients’ medical conditions that contraindicate microvascular anastomosis (i.e., prothrombotic conditions)

3. Defects that require concurrent coverage of the carotid vasculature.

4. Lack of adequate free flap donor site due to medical disease (i.e., PVD, previous surgery/trauma)

5. Unavailability of microvascular surgeon experience and expertise

6. Patient preference

State-of-the art microvascular free flaps are often required for large defects (larger than acceptable PMMF paddle), with reconstructions requiring different anatomic components (i.e., bone and soft tissue) and/or surgical defects that require complex three-dimensional reconstructions using thin pliable tissue (i.e., multiple plane and/or narrow diameter reconstructions). Successful reconstruction in some of these cases can be achieved with a PMMF, if there remains sufficient pharyngeal mucosa after the ablative resection or a circumferential reconstruction is not required.

Surgical Planning

The pectoralis major muscle is a fan-shaped muscle with origins extending from the medial clavicle, the manubrium, the sternum, the anterior surfaces of the ribs 4 to 6, and some extension to the upper rectus abdominis fascia. The insertion is on the upper third of the humerus along the crest of the greater tubercle. Blood supply to the pectoralis major muscle is supplied by two arteries, the pectoralis branch of the thoracoacromial artery and the lateral thoracic artery. Both arteries arise from the axillary artery. Its blood supply, however, does not follow the fanning fibers of the muscle but inserts into the undersurface of the muscle, through the clavipectoral fascia.

The thoracoacromial artery runs deep to the middle third of the clavicle and usually has four branches, of which the pectoral branch pierces the clavipectoral fascia that surrounds the subclavian muscle and the pectoralis minor muscle. The pectoral branch then inserts on the underside of the pectoralis major muscle through its surrounding fascia with a vein and is readily visible on the undersurface of the muscle. The lateral pectoral nerve is usually near this vascular bundle and can also be seen inserting into the undersurface of the pectoralis major muscle. During flap elevation, both structures can be readily visualized and palpated to assist in their protection.

The pectoral branch of the thoracoacromial artery is usually the dominant blood supply to the muscle, but the lateral thoracic artery may give significant blood supply to both muscle and skin and should be preserved if possible. The lateral thoracic artery pierces the clavipectoral fascia laterally through the pectoralis minor muscle to enter the pectoralis major muscle. As noted, the lateral thoracic artery arises from the second portion of the axillary artery, but in 10% of patients, it may also arise as a branch off of the thoracoacromial artery.

An important consideration for the surgeon is the course of these two vessels. A line from the acromion to the xiphoid process is suggested as a landmark to grossly locate the course of the pectoral branch in the major muscle. However, the pectoral branch may have an arced rather than radial course in the pectoralis major muscle, prompting careful visualization of its course when dividing the pectoralis major muscle fibers for flap elevation. The lateral thoracic artery, traversing a more lateral route along the lateral border in the pectoralis minor muscle, may sometimes travel for several centimeters in that muscle before exiting the minor and entering the major muscle.

Generally, the pectoralis branch supplies the majority of the skin perforators overlying the pectoralis major muscle directly, while the lateral thoracic artery supplies the skin perforators beyond the border of the pectoralis major muscle laterally and inferiorly. For this reason, it is an important consideration to try to preserve the lateral thoracic artery, when possible, when evaluating the placement and design of the skin paddle. The needed arc of rotation of the PMMF may dictate the ability to save this lateral pedicle. Preservation of the lateral thoracic artery may limit the arc of flap rotation for the PMMF to the level of the tonsil fossa. Other vascular supplies to the pectoralis major that are necessarily sacrificed during flap harvesting include the superior thoracic artery and the intercostals and internal mammary perforating arteries.

The medial and lateral pectoral nerves innervate the pectoralis major muscle. They derive their motor roots C5-T1 through the brachial plexus as it courses under the pectoralis muscle through the axilla. The nerves are so named because the medial pectoral nerve arises from the medial cord of the brachial plexus and the lateral pectoral nerve arises from the lateral cord of the brachial plexus. Their courses to the pectoralis major muscle, however, give a different visual presentation to the surgeon. The lateral pectoral nerve is located more medially, in closer proximity to the vascular pedicle of the pectoral branch and vein. It is readily visible in this undersurface of the pectoralis major muscle and must be divided. This division is performed to reduce eventual bulk of the muscle flap through atrophy and also to release tethering tension to allow more arc of rotation and extension of the flap. It also must be divided to reduce the risk of strangulation of the pectoral branch of the artery after placement of the myocutaneous flap for the reconstruction. The lateral pectoral nerve would otherwise form a compressive band across the vascular pedicle that has just been rotated up and over the firm immovable clavicular bone. The medial pectoral nerve is also readily visible between the pectoralis minor and major muscles. Although named the medial pectoral nerve, as noted, it pierces through the pectoralis minor muscle more laterally, through the clavipectoral fascia and then into the undersurface of the pectoralis major muscle. It also must be sacrificed during mobilization of the flap for reconstruction.

A thorough understanding of the surgical anatomy will greatly improve the viability and success of the PMMF reconstruction (Fig. 10.1A and B).

FIGURE 10.1 A. The pectoralis major muscle is supplied by the pectoral branch of the thoracoacromial artery. The vascular anatomy of the pectoralis major muscle is demonstrated here. B. Demonstrates the design of the skin paddle for the pectoralis flap (blue) and the preservation of the DP flap (black dotted line).

Usually, the reconstruction of a defect in the lateral pharyngeal wall is performed immediately following the resection. Secondary reconstructions may be necessary to repair a fistula, radiation necrosis, or stricture or due to the medical stability of each patient. Prereconstruction clearance of surgical margins, meticulous hemostasis, and identification/preservation of important recipient bed neurovascular structures are important before embarking on the reconstruction.

The chest is usually widely prepped and draped concurrent with the head and neck region. The use of barrier drapes can help separate any gastrostomy tube from the donor site. Until the harvest occurs, the area is usually covered with sterile towels and drapes to prevent contamination from the aerodigestive dissection superiorly as much as possible. Typically, during harvest, a separate OR table and instruments are used after the surgeon regowns to minimize contamination into the donor site or any tumor seeding potential. If the patient can be safely pharmacologically paralyzed during this aspect of the procedure, it is desirable to minimize muscular contraction during harvest.

For this example, a pectoralis flap is the best tissue to use to reconstruct an inferior lateral pharyngeal defect resulting from local recurrence and fistula formation after total laryngectomy (Figs. 10.2 and 10.3).

FIGURE 10.2 This photograph demonstrates a pharyngocutaneous fistula. Reconstruction of this defect is best accomplished with a pedicle flap of vascularized muscle and skin.

FIGURE 10.3 To reconstruct the defect, the edges of the fistula are prepared for reconstruction. An elliptical incision is made around the fistula to prepare for reconstruction.

The representative case in the accompanying figures is a 68-year-old male with fistula formation of the right lateral pharynx after total laryngectomy with neck dissection and postoperative radiation therapy. After neck dissection and excision of nonviable tissue, the right lateral pharyngeal defect is measured.

Accurate assessment of the defect is the first important step in the reconstruction. Once the dimensions of the defect and its location and character are known, the size of the PMMF skin paddle needed can be determined. Proper placement of the skin paddle incisions is crucial. Finding the most inferior skin paddle margin is done first, in measuring the arc of rotation needed to reach the most superior edge of the defect without tension. This is accomplished by using either an unrolled 4 × 4 gauze or the umbilical tape that would have been used with the tracheotomy. The pivot point of the arc of rotation is located at the emergence of the vascular pedicle to the PMMF, at the middle third of the inferior border of the clavicle. This measurement is important to assure that the edge of the skin paddle will reach the superior aspect of the defect without tension, when the flap is rotated into position. It also alerts the surgeon as to the amount of skin paddle that may be needed beyond the pectoralis major muscle and thus may require inclusion of the rectus sheath for vascular perfusion.

The skin lying most medial and inferior on the pectoralis major has the fullest arc of rotation but often needs to be extended more inferiorly below the border of the pectoralis major muscle. The blood supply to this portion of most inferior skin is usually random but may have some supply from the lateral thoracic artery previously mentioned. It is important, however, to include the rectus fascia to capture as much random blood supply as possible. Knowing then the placement of the inferior edge of the skin paddle and the dimensions of the defect to be closed, a skin paddle is designed for the pedicled PMMF (Fig. 10.4).

FIGURE 10.4 The appropriate skin paddle is designed on the chest wall to prepare for harvest of the flap.

Similar evaluation of the superior aspect of the skin paddle is tested using the gauze measurement technique to make sure that the superior aspect of the flap approaches the location of the inferior aspect of the defect. The center of the paddle is usually placed midline between the nipple and sternum but can extend to include both structures laterally and medially as needed. Too small a cutaneous paddle should not be drawn, as this will limit the number of cutaneous perforators to the paddle and compromise the entire cutaneous portion of the PMMF. Most skin paddles are drawn in a boat shape with the “pointy” bow of the boat being the superior aspect of the skin paddle and the “boxy” stern of the boat being the inferior aspect of the skin paddle. This paddle shape will help facilitate the closure of the chest wall defect. Elliptical-shaped paddles are also useful to help have an easier and more cosmetic donor site closure. As a general rule, the paddle should remain above the costal margin to ensure the best vascular supply to the distal portion of the PMMF.

The skin paddle is then drawn to size based on the accurate measurements of the defect. An oblique incision line from the superior lateral corner of the skin paddle to the anterior axilla is drawn. This incision line is important for two reasons. It helps to locate the lateral border of the pectoralis major muscle during flap harvest, thereby aiding in identifying the neurovascular boundaries rather than cutting across them with the skin incision. This incision is also placed, to avoid crossing into the region of the DP flap blood supply if this should be needed in a future surgery (Fig. 10.5).

FIGURE 10.5 The incisions to harvest the pectoralis muscle are performed in such a way that the skin of the DP flap is left uninterrupted in the event that it is required for later reconstruction.

The first incision made is from the anterior axilla to the superior apex of the skin paddle. This is then continued down the lateral portion of the skin paddle. These lateral incisions are made first to enable visualization of the lateral border of the pectoralis muscle, especially its most inferior extent. The inferior extent determines the extent of the cutaneous paddle that has the best axial blood supply. The remaining portion of the skin paddle beyond the inferior aspect of the pectoralis muscle is generally random in nature but usually reliable within limits. Determination of the inferior border of the pectoralis muscle may also allow further inferior placement of the skin paddle (redraw the paddle) as no other paddle incision have been made. This may result in less tension once the PMMF is rotated into a higher defect. It may also require more superior paddle harvest if the muscle is very short to ensure adequate blood supply to the inferior skin paddle.

Care is taken not to incise the pectoralis major fascia, while identifying the lateral border of the muscle. This also helps to avoid separating the fibers of the pectoralis major muscle and inadvertently injuring the lateral thoracic blood supply to the muscle. This also helps to distinguish the pectoralis muscles from the external oblique and serratus anterior muscles. The lateral incisions are subsequently undermined laterally enough in a plane superficial to the plane of the pectoralis fascia.

After the correct skin paddle location is again confirmed, the incisions are then continued circumferentially around the marked skin paddle, with care again not to incise the pectoralis major muscle fascia. The chest skin flap is medially dissected in the similar suprafascial plane toward the sternum and similarly for the inferior skin paddle incision toward the costal margin or below. Care is taken to not apply shearing forces on the skin paddle, as it remains attached to the pectoralis muscle, that can hurt the perforating vessels, thus devascularizing the carefully designed skin paddle, bringing a disastrous effect to the final reconstruction. Absorbable 3-0 sutures are placed to anchor the skin paddle to the fascial surface of the pectoralis major muscle to reduce any shearing during flap harvest (Fig. 10.6).

FIGURE 10.6 The skin paddle harvested on the pectoralis major muscle is sutured to the muscle to prevent stress and shear on the vascular perforators.

The skin of the chest is then elevated superiorly and medially up to the clavicle to expose the pectoralis major muscle. Important considerations must be adhered to when elevating this chest skin flap. The dissection remains suprafascial to the pectoralis major until the line of the imaginary DP flap is traversed. The dissection then becomes subfascial to the pectoralis major fascia, in hopes of preserving the blood supply from the internal mammary perforators at the first four medial intercostal spaces to the DP region. This again helps preserve the blood supply of the DP flap should it be necessary in the future (Fig. 10.7). Attention is also needed when in the subfascial plane not to divide the pectoralis muscle fibers while approaching the clavicle. Care must be taken in the dissection since one could easily separate the clavicular head from the sternal head of the pectoralis major muscle and injure the pectoralis branch of the thoracoacromial artery. Subcutaneous dissection into the neck space is performed from both below and above. The tunnel should be of sufficient size to allow passage of the PMMF, without strangulation of its vascular pedicle. Usually, a four-finger width is sufficient. It is important to note that there are usually veins from the external jugular system that traverse over the clavicle medially and laterally to this tunnel and should be ligated to avoid postoperative hematoma formation. It is important to perform this elevation prior to incising and releasing the flap inferiorly. Once the PMMF is released from its costal attachments inferiorly, it bunches in the superior aspect due to the loss of tension and makes this superior chest skin flap dissection more technically difficult if not already performed.

FIGURE 10.7 The dissection in this photo is subfascial to the pectoralis major fascia to preserve the blood supply from the internal mammary perforators at the first four medial intercostal spaces to the DP region. This again helps preserve the blood supply of the DP flap should it be necessary in the future.

The sternocostal insertions of the pectoralis major muscle are then separated from their attachments using Bovie cautery. This is approached widely and inferiorly, starting in a subfascial plane at the rectus fascia if the inferior margin of the skin paddle flap reaches to this level as needed for the reconstruction (Fig. 10.8). A wide base of the sternocostal margins of the pectoralis major muscle helps to protect the terminal branches of the pectoral artery. Taking a narrow strip of muscle may otherwise injure the vascular bundle from the thoracoacromial artery. The surgeon is reminded that the thoracoacromial artery may have a tortuous course to the inferior edge of the pectoralis major muscle. Care must be taken to not extend the cauterizing dissection deep to the level of the ribs and potentially penetrate the chest cavity.

FIGURE 10.8 The dissection is performed in the subfascial plane at the rectus fascia if the inferior margin of the skin paddle flap reaches to this level as needed for the reconstruction.

The medial fibers of the pectoralis major muscle fibers are then divided from inferior near the xiphoid process in a superior line up to the medial third of the clavicle. It is important to stay lateral to the course of the internal mammary artery and its first four perforators superiorly, again, to avoid devascularizing the DP skin flap for the future if needed. In the inferior half of the medial flap harvest, intercostal arterial branches will be encountered and good hemostatic technique can help minimize subsequent hematoma formation.

The PMMF is now elevated from its costal insertions in an inferior to superior fashion. This usually requires cautery dissection in the inferior half of the flap harvest to separate the muscle from its costal attachments, but more superiorly, simple finger dissection in the plane between the pectoralis major and minor muscles can occur. The vascular bundle with the pectoral branch will be in full view within the pectoralis major fascia coming from superiorly. It is also readily palpable. The pectoralis minor muscle, with its origins on the costal rib attachments and clavipectoral fascia, are left intact. The lateral pectoral nerve will also be identified as it enters the undersurface of the pectoralis major and is divided (Fig. 10.9). Look for the lateral insertion course of the lateral thoracic artery and determine if it may also be preserved while maintaining adequate length for the rotation advancement of the PMMF, particularly if a random portion of the skin paddle is incorporated with the rectus fascia.

FIGURE 10.9 The lateral pectoral nerve should be identified as it enters the undersurface of the pectoralis major and is divided.

The PMMF is then gently rotated and guided through the tunnel, avoiding any twisting or tethering of the vascular pedicle or shearing of the skin paddle attached to the muscle (Fig. 10.10). If necessary, the flap can be rotated some to allow the skin paddle to be located externally to close a cutaneous defect, but this requires a larger tunnel and longer flap pedicle. Also, this type of defect may be better reconstructed with a skin graft on top of the pectoralis muscle rotated into position without twisting.

FIGURE 10.10 The PMMF is rotated and guided through the tunnel, avoiding any twisting or tethering of the vascular pedicle, or shearing of the skin paddle attached to the muscle.

The skin paddle, which is fashioned slightly larger than the size of the defect, is sewn in one layer to the pharyngeal mucosa, incorporating the fascia, dermis, and skin. Usually, absorbable suture is used with adequate strength (3-0). Other layers of closure may also be added judiciously, and these may also help support the flap in position against gravitational forces (sewing muscle fascia to mandibular periosteum or to a locking reconstruction plate) (Fig. 10.11). As the PMMF pedicle now lies superficially on the surface of the PMMF in the neck, one must be careful in the placement of subsequent sutures and closure. Having the skin paddle slightly larger than the defect will avoid a tense skin surface at closure, which could also compromise the vascular flow to the skin flap.

FIGURE 10.11 The layers of closure may also be added judiciously, and these may also help support the flap in position against gravitational forces (sewing muscle fascia to mandibular periosteum or to a locking reconstruction plate).

During inset of the flap, the tension on the PMMF pedicle must be minimal or else further improvement in the rotation arc flap must be undertaken or the skin paddle repositioned. Improvement in the rotation of the arc can be obtained by releasing the humeral head of the PMMF, sacrifice of the lateral pedicle, and even takedown of a section of the clavicle bone. Flexing the neck can assist some but should not be relied upon as the sole remedy. The described temporary sutures holding the skin paddle to the muscle can be maintained or removed depending on the mobility of the skin paddle needed.

With the reconstruction complete, drains are placed in the neck wound. These should not be placed over the vascular pedicle. Attention is turned toward closure of the neck incision. The neck portion of the PMMF pedicle can be moved with some degree of freedom horizontally without causing tension. This can be advantageous to fill any dead space and cover any potential exposed neck vessels. Full closure of the neck incisions should occur only if there is no excessive tension on the flap. Sometimes, the bulk of the PMMF will prevent a tension-free or strangulation-free closure of the neck incision. If this is the case, then a split-thickness skin graft is placed over the exposed muscle belly of the pectoralis major and sutured to the skin edges of the neck incision in a loose tension-free closure (Fig. 10.12). At times, a vertical incision is also needed from the inferior neck incision toward the clavicle to release neck flap skin tunnel tightness over the PMMF pedicle. The exposed pedicle muscle can then be skin grafted as well. Usually, a simple overlying Xeroform gauze is all that is needed to keep the graft moist and facilitate adherence. A bolster may apply too much pressure on the PMMF pedicle. Cutaneously, the location of a palpable or dopplerable PMMF pedicle is marked with a suture to facilitate monitoring of the flap viability postoperatively.

FIGURE 10.12 A split-thickness skin graft is placed over the exposed muscle of the pectoralis major and sutured to the skin edges of the neck incision in a loose tension-free closure.

The chest incision is usually closed primarily after wide undermining of the skin laterally and inferior medially. There is often an area of tension in this closure, but extensive undermining should be adequately done to make this tension as small as possible. Skin grafting at the donor site onto the chest wall is also an option (Fig. 10.13). For females, there is some distortion of the breast in the closure of this donor site, but this can be minimized with skin paddle design for the initial incisions. The use of some of the medial breast tissue can also provide bulk for the flap reconstruction if needed. Suction drains are inserted into the chest donor site per surgeon preference.

FIGURE 10.13 The donor site closure is usually achieved by rotating a large skin flap into the defect. Typically, this can be achieved with primary closure.

If a tracheostomy for maintenance of airway protection is required, it is sutured into position, and not tied, to avoid any circumferential ties and strangulation of the vascular PMMF pedicle. This can include compression from respiratory therapy ties to the tracheostomy mask or tight patient gowns.

Postoperative management requires that the nonirradiated patients remains NPO for 7 days and radiated patients remain NPO for 14 days. I schedule a barium swallow before initiating an oral diet.

Complications may be related to the pectoralis donor site and the pharyngeal recipient site. Donor site complications are typically limited to wound breakdown because the pectoralis flap is straightforward to harvest and associated with very few significant neurovascular complications. The recipient site is at risk for fistula and infection. In turn, a salivary fistula may place the great vessels at risk. The muscle flap associated with the pectoralis donor site provides well-vascularized tissue in the event of a fistula.

In my experience, the results with this technique are excellent. The donor site is reliable, and the skin flap is ideal for pharyngeal reconstruction.

• Prepare with an optional reconstructive plan should the lateral pharyngeal defect involve more than 50% of the circumference of the pharynx or invade the base of the tongue or larynx.

• Include the rectus fascia when the skin paddle design length extends below the limits of the pectoralis major muscle border. Preservation of the lateral thoracic artery should also be desired for the survival of the extended skin paddle.

• The pectoral branch to the PMMF may be an arc rather than a straight line course through its length.

Visualization during mobilization of the flap will avoid inadvertent injury to the vascular pedicle.

• Do not incise the pectoralis major fascia surrounding the skin paddle, with surrounding dissection being suprafascial to preserve perforating blood supply. This fascia provides strength to the inset sutures.

• Dissection superior to the DP flap inferior demarcation is subfascial to preserve the potential DP flap future reconstruction. Avoid injury of the internal mammary artery perforators of the first three intercostal spaces inferior to the clavicle.

• Flap tension will lead to flap failure.

• Any dissection around the vascular pedicle or the investing clavipectoral fascia risks injury and failure of the pectoralis major flap. The clavicular and sternal attachments are divided for length instead.

• Division of the horizontal fibers of the pectoralis major muscle near its insertion to the humeral attachment for arc of rotation length improvement will avoid injury to the pectoral branch vessel but may of necessity divide the lateral thoracic artery branch. This later vessel division can be minimized, if done in a stepwise fashion, first through small increments of the horizontal muscle fibers, to titrate to the needed length of reach without tension.

• Failure to divide the lateral pectoral nerve may strangulate the vascular pedicle of the pectoral branch if left intact for the rotation of the flap over the clavicle. Failure to divide the nerve will also reduce the length of the arc of rotation for the flap and allow persistent innervation of the muscle. This can yield bothersome voluntary contractions in the neck postoperatively, as well as prevent desirable muscle atrophy.

• Excessive undermining of the skin to the sternum superiorly above the fourth intercostal space will sacrifice the internal mammary artery perforators to a future DP flap.

• Suturing under tension a too-small skin paddle for the lateral pharyngeal defect may cause taut skin tension and compromise the perforating blood supply to the entire skin paddle.

• Head and neck surgical tray

I gratefully acknowledge the contributions of Mark J. Furin and Lisa Shnayder.

SUGGESTED READING

Ariyan S. The pectoralis major myocutaneous flap: a versatile flap for reconstruction in the head and neck. Plast Reconstr Surg 1979;63:73–81.

Magee WP Jr, McCraw JB, Horton CE, et al. Pectoralis “paddle” myocutaneous flaps: the workhorse of head and neck reconstruction. Am J Surg 1980;140:507–513.

Baek S, Lawson W, Biller HF. An analysis of 133 pectoralis major myocutaneous flaps. Plast Reconstr Surg 1982;69: 460–467.

Ossoff RH, Wurster CF, Berktold RE, et al. Complications after pectoralis major myocutaneous flap reconstruction of head and neck defects. Arch Otolaryngol Head Neck Surg 1983;109:812–814.