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PEDICLED MYOCUTANEOUS FLAPS IN HEAD AND NECK SURGERY

ANDREW A. JACONO, MD, AUGUSTINE L. MOSCATELLO, MD

Reconstruction of head and neck surgical defects has undergone significant refinement in the last 2 decades. This modern era of reconstruction began with the introduction of the pectoralis major myocutaneous flap. This article attempts to summarize the anatomical and surgical aspects of this procedure. The principles of this reconstructive technique are applicable to other regional flaps used in head and neck reconstruction.

Before the introduction of pedicled flaps, surgical treat- ment of head and neck tumors was limited by the lack of reliable techniques to repair the surgical defects. Reconstruc- tion of these defects was often protracted and frequently resulted in failure. Many tumors were deemed unresecta- ble because of the difficult reconstructive problems their extirpation would have presented. A revolution in head and neck reconstruction was ushered in with the introduc- tion of the pedicled myocutaneous flap. The current use of free flaps is an extension of the principles of reconstruction on which the pedicled flap is based. In 1955, Owens 1 described the first application of the pedicled myocutane- ous flap for head and neck reconstruction using a latissi- mus dorsi flap to reconstruct a mandibular defect. Despite this description, myocutaneous flaps did not gain popular- ity over the next 20 years. It was not until 1979 that the use of the pedicled flap in head and neck reconstruction became widely accepted. A small series by Ariyan, 2 and then a larger series in the same year by Baek et aP introduced the use of the pectoralis major myocutaneous (PMC) flap for routine head and neck reconstruction.

Since its introduction, the PMC flap has been used widely for reconstruction of oral cavity, oropharyngeal, and facial (including orbital) defects, as well as repair of oropharyngeal fistula. 4-8

In recent years, the most common use of the pectoralis myocutaneous flap in our institution has been in patients requiring laryngectomy after radiation therapy. With the recent advent of combined chemotherapy and radiation therapy as part of laryngeal preservation protocols, there has been an increase in the number of patients requiring laryngectomy after radiation failure. Bringing vascular- ized, unradiated tissue to the surgical site to serve as the anterior wall in the reconstructed neopharynx reduces the risks of poor wound healing and postoperative pharyngo- cutaneous fistula. 8 The pectoralis muscle can be used with or without a skin paddle in this situation. If used as a

From the Department of Otolaryngology-Head and Neck Surgery, the New York Eye and Ear Infirmary; Department of Otolaryngology-Head and Neck Surgery, New York Medical College, Valhalla, NY; and the Depart- ment of Otolaryngology-Head and Neck Surgery, Westchester Medical Center, Valhalla, NY.

Address reprint requests to Augustine L. Moscatello, MD, FACS, Director, Department of Otolaryngology-Head and Neck Surgery, Westchester Medical Center, Valhalla, NY 10595.

Copyright © 2000 by W.B. Saunders Company 1043-1810/00/1102-0013510.00/0 doi:10.1053/otot.2000.8260

myofascial flap, remucosalization from the native tissue occurs. The anatomy of the pectoralis muscle as well as its vascular pedicle are straightforward, and many consider it to be an ideal flap for reconstruction because of its accessibility, reliability, and minimal donor-site morbidity. Its ability to allow closure of surgical defects in a 1-stage procedure obviated the need for repairs that required multiple, staged procedures.

ANATOMY

The PMC flap is an axial-pattern, pedicled, myocutaneous chest flap. The pectoralis muscle is a fan-shaped muscle that covers the anterior chest wall, originating from the sternum and medial half of the clavicle, superiorly, and extending to the upper 7 costal cartilages, medially, and the lower ribs, inferiorly.

The major blood supply to the muscle is the thoracromi- nal artery, a branch of the axillary artery. It descends between the pectoralis major and minor muscles and gives off 4 branches, the largest being the pectoral branch, which is the major supply to the pectoralis muscle (Fig 1). Additional blood supply to this muscle may also include the lateral thoracic artery and perforating vessels of the internal mammary artery. These branches are transected during elevation of the flap, and therefore do not contrib- ute to the vascularity of the flap. The cutaneous portion of the flap is fed by small feeding vessels from the underlying muscle. Essential to the survivability of this flap are its arterial supply with sufficient perfusion pressure to the distal edge of the flap, and adequate venous drainage. Subsequently, other pedicled flaps were introduced. A summary of these is presented in Table 1.

TECHNIQUE

The design of the PMC flap is begun by marking a skin island of desired shape and size between the nipple and edge of the sternum. In males, a line is then drawn from the upper, lateral border of the skin paddle to the axilla (Fig 2A). In women, the design is modified to minimize cosmetic distortion of the breast. The skin-paddle incision is placed off of the breast, and the incision is extended along the inframammary crease (Fig 2B). 1°

The incision is carried down to the pectoralis fascia, and the skin flaps surrounding the paddle are elevated superi- orly, medially, and laterally. The superior skin flap is elevated over the clavicle and into the inferior neck to

OPERATIVE TECHNIQUES IN OTOLARYNGOLOGY--HEAD AND NECK SURGERY, VOL 11, NO 2 (JUN), 2000: PP 139-142 1 3 9

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FIGURE 1. illustration of the major blood supply to the pectoralis major myocutaneous flap.

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create a tunnel that allows access to the neck, and then to the oral cavity, oropharynx, or facial skin. This tunnel should be wide enough to allow passage of the pedicled portion of the flap, roughly the width of 3 to 4 fingers. If too small, the resultant constriction of the flap pedicle will reduce blood flow, leading to loss of the cutaneous paddle and possibly the underlying muscle.

Care is taken throughout this dissection not to acciden- tally apply shearing forces to the skin paddle and disrupt the perforating blood supply from the underlying muscle to the skin. This can be facilitated by suturing the edges of the skin paddle to the underlying muscle with an absorb- able suture (Fig 3).

Next, the pectoralis muscle is incised medially along the lateral border of the lower half of the sternum, lateral to the first 2 intercostal perforators (Fig 4). The inferior muscle attachments to the ribs are cut, and the muscle is dissected superiorly off the chest wall, separating the pectoralis major from the pectoralis minor. The pectoralis branch of the thoracromial artery and its accompanying vein are identified on the deep surface of the muscle. Lastly, the humeral attachments of the muscle are lysed, leaving the pectoralis major attached by its clavicular attachments and its vascular pedicle (Fig 5). The muscle surrounding the vascular pedicle can then be thinned to lessen the muscle bulk in the neck without compromising the flap. The flap is rotated 180 ° , placed through the subcutaneous tunnel and over the clavicle. The flap is folded upward, taking care not to twist the flap at the pedicle, avoiding strangulation of the artery and vein. It is now in good position to be

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FIGURE 2. (A) Design of the incision for the pectoralis major myocutaneous flap. (B) Modification for females with placement of incision in the inframammary crease.

maneuvered through the neck incision to close the surgical defect (Fig 6). The lateral thoracic arteries may tether the flap, limiting its placement superiorly. When this is the case, these may be lysed after the pectoral branch of the

TABLE 1. Description of Other Myocutaneous Flaps Used in Head and Neck Reconstruction

Myocutaneous Flap Arterial Supply Advantages Disadvantages

Latissimus dorsi Thoracodorsal Largest volume of regional donor tissue; flap can reach vertex of skull

Trapezius Thin, supple flap well suited for intraoral applications

Sternocleidomastoid

Transverse cervical Dorsal scapular Occipital Paraspinal perforators Occipital Superior thyroid Thyrocervical trunk

Provides readily available tissue

Semilateral position required to harvest

Limited arc of rotation

Not an axial flap, less reliable

140 PEDICLED MYOCUTANEOUS FLAPS

FIGURE 3. Suturing the edges of the skin paddle to the underlying muscle with an absorbable suture helps prevent shearing forces on the perforating vessels to the cutaneous paddle.

thoracromial has been identified. Additional flap length can be obtained by resecting a section of the clavicle and replacing it after the flap is passed into the neck. To avoid the effect of gravity pulling the flap away from the donor site, tacking sutures are placed along the periphery of the flap, suturing it to the surrounding native tissue. The tacking sutures should be placed well along the periphery of the pedicle to avoid the accidental ligation of the vascular supply to the flap. Suction drains are placed medially and laterally on the chest wall, and the donor-site defect is closed primarily.

The pectoralis major myocutaneous flap is the work- horse flap in the field of head and neck reconstruction. In the 20 years since its popularization, it has proven to be a reliable means of providing soft tissue and skin to defects of the head and neck. Like all surgical procedures, it has complications and limitations. Total flap necrosis has been reported to be as high as 4% in large series, while partial flap necrosis has been noted in up to 17% of patients. ~-14

FIGURE 5. Flap elevated and attached by its vascular pedicle and clavicular attachments.

Such tissue loss may result in oropharyngeal- and orocuta- neous fistulae or carotid exposure. The major limitations of this flap include its bulk, especially in those with large amounts of adipose tissue, and its limited ability to reach more cephalic defects of the face as a result of limited length. Additionally, hair-bearing skin in the mouth or pharynx could be problematic.

SUMMARY

Despite major advances in head and neck reconstruction in the past 15 years, the myocutaneous flap retains an important role in the surgeon's reconstructive armamen- tarium. Among the myocutaneous flaps used in the head

FIGURE 4. Dissection of the myocutaneous paddle.

JACONO AND MOSCATELLO

FIGURE 6. Flap tunneled under cervical skin and sutured into the floor of the oropharynx.

141

a n d neck, the pec to ra l i s m a j o r f lap is the one m o s t c o m m o n l y used . Its p r o v e n rel iabi l i ty , r e l a t ive ly s t r a igh t fo r - w a r d su rg ica l t e chn ique , a v a i l a b i l i t y w i t h i n the h e a d a n d neck su rg ica l f ield, a n d c o m p a r a t i v e l y s h o r t e n e d o p e r a t i n g t ime h a v e a l l o w e d the f lap to be cons i s t en t l y r e l i ed on s ince its i n t roduc t i on . Its u se fu lne s s wi l l m o s t l i ke ly c o n t i n u e into the fo re seeab le fu ture .

REFERENCES

1. Owens NA: A compound neck pedicle designed for repair of massive facial defects: Formation, development, and application. Plast Recon- str Surg 15:369-374, 1955

2. Ariyan S: The pectoralis major myocutaneous flap: Aversatile flap for reconstruction in the head and neck. Plast Reconstr Surg 63:73-81, 1979

3. Baek S, Biller H, Krespi Y, et al: The pectoralis myocutaneous island flap for reconstruction of the head and neck. Head Neck Surg 4:293-300, 1979

4. Wilson S, Yiacoumettis AM: Some observations on 112 pectoralis major myocutaneous flaps. Am J Surg 147:273-279,1987

5. Magee WP, McCraw JB: Pectoralis "paddle" myocutaneous flaps. The workhorse of head and neck reconstruction. Am J Surg 140:507-513, 1980

6. Schuller D: Limitations of pectorahs major myocutaneous flaps in

head and neck cancer reconstruction. Arch Otolaryngol 106:709-714, 1980

7. Ariyan S: Myocutaneous flaps for head and neck reconstruction. Head Neck Surg 2:321-345, 1980

8. Ariyan S, Cuovono CB: Use of pectoralis major myocutaneous flap for reconstruction of large cervical, facial, or cranial defects. Am J Surg 140:503-506,1980

9. Zbar GL, Funk GF, McCulloch TM, et al: Pectoralis major myofascial flap: A valuable tool in contemporary head and neck reconstruction. Head Neck 19:412-418, 1997

10. Cotman MF, Zemplenyi J: Design of incisions for pectoralis myocuta- neous flaps in women. Laryngoscope 96:695-696, 1986

11. Kroll SS, Goepfert H, Jones M, et al: Analysis of complications in 168 pectoralis major myocutaneous flaps used for head and neck recon- struction. Arm Plast Surg 25:93-97, 1990

12. Mehrof A1, Rosenstock A, Neifeld JP, et ah The pectoralis major myocutaneous flap in head and neck reconstruction: Analysis of complications. Am J Surg 146:478-482,1983

13. Biller H, Baek S, Lawson W, et al: Pectoralis major myocutaneous flap in head and neck reconstruction: Analysis of complications in 42 cases. Arch Otolaryngo1107:23-26, 1981

14. Baek S, Lawson W, Biller H: An analysis of 133 pectoralis major flaps. Plast Reconstr Surg 69:460-469, 1982

15. Zbar GL, Funk GF, McCulloch TM, et al: Pectoralis major myofascial flap: A valuable tool in contemporary head and neck reconstruction. Head Neck 19:412-418, 1997

142 PEDICLED MYOCUTANEOUS FLAPS