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

7. Management of the Total Glossectomy Defect: Pectoralis Major Myocutaneous Flap

Patrick J. Gullane

INTRODUCTION

The pectoralis major myocutaneous flap was first described by Ariyan in 1979. It is a reliable, robust, and easily harvested pedicled flap that was the most popular technique for head and neck reconstruction prior to the introduction of free tissue transfer. Though widely used in the past for reconstruction following total glossectomy, it has now been replaced almost entirely by free tissue microvascular flaps, such as radial forearm fasciocutaneous flap, anterolateral thigh fasciocutaneous flap, latissimus dorsi myocutaneous flap, rectus abdominis myocutaneous flap, and gracilis myocutaneous flap. However, for select patients in whom free tissue transfer is not an option, the pectoralis major myocutaneous flap offers a reliable reconstructive procedure following both primary and salvage surgery.

The tongue serves three main functions: deglutition, articulation, and airway protection. Reconstruction of a total glossectomy defect must take these functions into consideration. The ideally reconstructed neotongue must have adequate dorsal height, bulk, anterior length, and support in order to enable the patient to swallow. Dorsal height is necessary to allow contact of the neotongue to the palate, so as to propel the food bolus posteriorly. Bulk is required for better quality of speech. The neotongue must also have sufficient anterior length to contact teeth to allow for articulation. Since the floor of the mouth and extrinsic tongue musculature is often resected, the neotongue must be adequately supported across the mandibular arch to prevent ptosis. Lastly, the suprahyoid and extrinsic tongue musculature act to elevate the larynx. Because these muscles are usually detached or excised during the ablation, laryngeal suspension to the mandible or a reconstruction plate in the anterosuperior vector is required to minimize postoperative aspiration.

A careful history is essential to understand the prior exposure to external beam radiotherapy, systemic chemotherapy, and prior surgery. When the patient has a history of prior radiotherapy, healing is often compromised. The pectoralis flap provides a vascularized muscle flap that is helpful in aiding healing. All prior exposures can impact on wound healing and the availability of donor vessels for microvascular reconstruction. In those patients with a history of prior neck dissection, the neck may be depleted of vessels for microvascular free tissue transfer. In such cases, regional flap reconstruction may be indicated. In addition, a careful review of the patient’s comorbidities can help determine if there are limitations to free tissue transfer or regional flap reconstruction.

Physical examination should entail a review of the defect and the chest wall to make sure that the anatomy of the chest wall is appropriate for reconstruction of the defect within the oral cavity. In the repair of the anterior aspect of the floor of the mouth, the pectoralis major myocutaneous may be inadequate in length to reconstruct a total glossectomy defect so that a tension free closure is achieved. In such a case, an alternative donor site will need to be used. Evidence of previous surgery in this area may eliminate the pectoralis flap as an option.

Examination of the defect is important to determine if laryngeal preservation can be accomplished with the glossectomy reconstruction. Glossectomy resections that involve the supraglottic larynx are poorly tolerated because aspiration is common. Pure total glossectomy defects can be reconstructed with the pectoralis flap; however, bulk is essential to protect the airway.

The indications for this technique are when a microvascular option is not available. Free tissue transfer offers an excellent option for the total glossectomy defect, but there are times when this cannot be achieved and a pectoralis flap is necessary.

The contraindications for this flap are when there is a concomitant mandible defect or if the skin paddle will not reach the anterior aspect of the oral tongue defect because of anatomic restrictions. Previous surgery, trauma, and radiation to the chest wall are also contraindications.

Total glossectomy is a life-altering procedure, and therefore, the patient’s capacity and motivation for rehabilitation must first be taken into consideration. The indication for concurrent total glossectomy and laryngectomy is dependent on the extent of disease or a patient’s pulmonary and functional status. Their pulmonary function may predict whether they will be able to tolerate some possible post operative mild aspiration if the larynx is preserved. The addition of a total laryngectomy is associated with greater morbidity and should only be considered in appropriately selected patients (Fig. 7.1). Nonoperative management, such as chemoradiation or, in some cases, palliative care, should also be discussed with these patients as alternate options.

FIGURE 7.1 Total glossectomy and total laryngectomy defect. Note uvula (asterisk). (Figure © Patrick J. Gullane.)

A tracheostomy is performed first to control the airway. Intraoral access can be achieved through a lip split and midline mandibulotomy/mandibulectomy or a lingual release into the neck. To avoid the confusion in the literature regarding the extent of a total glossectomy, we define a “total glossectomy” as resection of the entire oral tongue and base of tongue as far posteriorly as the epiglottis (Fig. 7.2). However, in situations where a subtotal glossectomy can be performed, attempts are made to preserve the hypoglossal and superior laryngeal nerves, and as much floor of the mouth mucosa and native tongue as is oncologically sound.

FIGURE 7.2 Total glossectomy, segmental mandibulectomy, bilateral neck dissection specimen. (Figure © Patrick J. Gullane.)

Using a flexible ruler, the longitudinal dimension is measured from the mandibular symphysis to the posterior extent of the resection (base of tongue, vallecula, or supraglottic larynx), allowing for dorsal curvature of the flap. The transverse dimension is measured from mandibular arch to mandibular arch, again allowing for dorsal curvature so that the flap contacts the hard palate.

Based on the thoracoacromial artery, the pectoralis major flap can be raised as a myocutaneous or fasciocutaneous flap. The skin paddle is designed over the inferomedial aspect of the flap vasculature. In women, the skin paddle is designed medial to the breast (to minimize the incorporation of mammary tissue into the flap), and a laterally based incision is still used, which then extends inferior to the breast along the inframammary fold to connect with the skin paddle.

The skin is incised with a scalpel to minimize thermal necrosis to the skin paddle. Using the monopolar cautery, the dissection is then carried down through subcutaneous tissue to expose the lateral and inferior borders of the pectoralis major muscle. Once the pectoralis major muscle is identified, the superior and inferior skin paddle incisions can be made so that the same paddle is positioned completely over the muscle to maximize the number of musculocutaneous perforators (Fig. 7.3A and B). The flap is then elevated off the chest wall fascia and the pectoralis minor muscle. Care is taken to avoid injury to the vascular pedicle, which lies on the deep surface of the pectoralis major muscle. Some have advocated suturing the skin paddle to the underlying muscle to prevent shearing injury during the harvesting process; however, in my experience, this is not necessary. Medially, perforators of the internal mammary artery must be preserved in case a deltopectoral flap is ever required for a subsequent soft tissue reconstruction. Laterally, the humeral attachment of the pectoralis major muscle must be released to permit rotation of the flap. Often, the lateral thoracic artery and lateral pectoral nerve must be divided to increase rotation and length and to decrease tethering of the flap. A broad subcutaneous tunnel is then created over the clavicle, and the flap is carefully delivered into the neck. The chest incision is closed over suction drains.

FIGURE 7.3 A. Pectoralis major myocutaneous flap in situ. B. Harvested pectoralis major myocutaneous flap. (Figures © Patrick J. Gullane.)

The pectoralis major myocutaneous flap is brought through the floor of the mouth with the proximal portion of the skin paddle forming the anterior aspect of the neotongue/floor of the mouth. The neotongue is then suspended across the mandibular arch by either suturing to the pterygoid musculature or securing to the mandible using drill holes. The flap is then sutured to the remaining mucosa from posterior to anterior (Fig. 7.4A). If there is not sufficient floor of the mouth mucosa to suture to, circumdental sutures can be used to support and secure the flap. Bunching up of excess tissue in the transverse and longitudinal dimension is favorable, so as to create a “mound” shape to the neotongue/floor of the mouth (Fig. 7.4B). If an anterior reconstruction plate is used, the pectoralis major muscle can then be wrapped around and secured to the plate to minimize plate exposure (Fig. 7.4C and D). Laryngeal suspension is then achieved by drilling holes in the thyroid cartilage and mandibular symphysis and suspending the larynx in an anterosuperior vector with heavy, permanent sutures.

FIGURE 7.4 A. Inset of pectoralis major myocutaneous flap. Note epiglottis posteriorly (asterisk). B. Intraoral view of inset pectoralis major myocutaneous flap. C. Flap inset with mandibular plate reconstruction. Note pectoralis major muscle secured to plate. D. Postoperative photograph at 1 year. (Figures © Patrick J. Gullane.)

Postoperative wound care is essential. I recommend placement of a gastrostomy tube during or prior to the procedure to help maintain nutrition during the healing process. All patients undergoing total glossectomy require aggressive speech and swallowing therapy after surgery. Studies reporting outcomes of total glossectomy reconstructed with pectoralis major myocutaneous flap are limited. However, the following can be concluded from my own experience: (1) Most patients regain oral intake; however, they are limited to liquid diet, (2) articulation is adequate, and (3) a small number of patients will ultimately require total laryngectomy due to aspiration.

There are few donor site complications; however, wound breakdown at the primary site is not uncommon. The weight of the pedicled flap and the very nature of a muscular pedicle can lead to breakdown of the oral wound. I use heavy absorbable sutures (2-0) to decrease the risk of wound dehiscence.

The potential advantages to the pectoralis major myocutaneous flap are the reliability of vessels and vascular pattern, ease of harvesting, robustness of the flap with good vascularity, and the fact that it is a regional flap not requiring vascular anastomosis in vessel-depleted necks. The disadvantages to the pectoralis major myocutaneous flap are the donor site defect, the loss of muscle bulk in the flap over time, excessive subcutaneous adipose tissue, and distal necrosis of the skin paddle. Additionally, in some patients, there may not be adequate length to position the pectoralis major myocutaneous flap in the oral cavity and remain tension free. The complication rate with the pectoralis major myocutaneous flap (flap or donor site) is reported to be approximately 35%. The prevalence of partial thickness skin sloughing ranges between 8% and 26%.

Though total glossectomy reconstruction has largely been replaced by microvascular free tissue transfer, the pectoralis major myocutaneous flap remains a reliable option for patients in whom free tissue transfer is not feasible. All head and neck oncologic surgeons should be able to use the pectoralis major myocutaneous flap for total glossectomy and other head and neck defects.

In my experience, the range of successful deglutition is 67% to 100%, with the average time to swallowing being 4.5 weeks (range 1 to 14). Since tongue movement is absent, the food bolus cannot be propelled posteriorly, so the diet is usually limited to full liquids. There was no difference in swallowing performance between pectoralis major myocutaneous flap and radial forearm free flap reconstruction. The range of adequate articulation is 92% to 100%; however, when compared to radial forearm free flap reconstruction, patients reconstructed with the pectoralis flap had better speech. The use of palatal augmentation prosthesis to facilitate contact of the palate and neotongue was shown to improve articulation. Subsequent total laryngectomy was required in 0% to 7.4% of patients for persistent aspiration.

• Make sure that the skin paddle is large enough to accommodate the defect.

• Lengthen the pedicle as much as possible to limit the drag on the skin paddle.

• Use heavy absorbable suture to secure the skin paddle in the oral cavity defect.

• The oral wound breakdown should be recognized early and treated.

• The pectoralis is a reliable flap, but the distal random aspect of the skin paddle may undergo necrosis. This should be carefully monitored.

• Standard head and neck surgical set

I gratefully acknowledge the contributions of Jason Rich and David Goldstein.

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.

Gullane PJ. Primary mandibular reconstruction: analysis of 64 cases and evaluation of interface radiation dosimetry on bridging plates. Laryngoscope 1991;101(54S):1–24.

Davidson J, Brown D, Gullane P. A re-evaluation of radical total glossectomy. J Otolaryngol 1993;22(3):160–164.

Haughey B. Tongue reconstruction: concepts and practice. Laryngoscope 1993;103:1132–1141.

Liu R, Gullane P, Brown D, et al. Major myocutaneous pedicled flap in head and neck reconstruction: retrospective review of indications and results in 244 consecutive cases at the Toronto General Hospital. J Otolaryngol 2001;30(1):34–40.

Su W, Hsia Y, Chang Y, et al. Functional comparison after reconstruction with a radial forearm free flap or a pectoralis major flap for cancer of the tongue. Otolaryngol Head Neck Surg 2003;128:412–418.