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

4. Management of the Defect in the Buccal Mucosa

Mark K. Wax

INTRODUCTION

The buccal mucosa is an integral part of the cheek. Pathologic processes that involves it may require consideration of reconstruction of the cheek complex. Consequently, this chapter focuses on the reconstruction of defects in the buccal mucosa but takes into consideration the entire cheek complex. The cheek is one of the major contributors to normal upper aerodigestive tract physiologic function, cosmesis, and the perception of oneself as well as what others think of you as an individual. Normal cheek function is important in the ability of individuals to eat, drink, and talk. Defects of this important anatomic area will result in a decrease in these functions. The face is the first structure that we see in the mirror, and others see when we interact with the outside world. Any abnormality in appearance is immediately fixed upon and can lead to severe social repercussions.

The most common cancer arising in the buccal mucosa is squamous cell carcinoma. In North America, lesions arising from the buccal mucosa are uncommon and may present as a visible mass in the cheek or as a mass distorting the buccal mucosa. In Southeast Asia where chronic exposures to carcinogens is part of the culture, squamous cell carcinoma is the most common cancer of the oral cavity. Even though the majority of cancers are squamous cell, a precise diagnosis by biopsy is needed. A detailed history, clinical examination, and imaging studies are essential in defining the location and extent of these cancers.

There are several options for reconstruction of the buccal mucosa including skin graft, local flaps, and free flap reconstruction. The size and depth of the defect will determine the optimal reconstructive option. A splitthickness skin graft (STSG) can be used for many of the defects in the buccal mucosa; however, this approach may be associated with scar contracture and trismus. The radial forearm skin tends to resist scar contracture and can be used for all defects, including those that penetrate through and through.

Reconstruction of the buccal mucosal defect can be achieved through a variety of techniques. Obtaining a history from the patient is essential to understand if the patient is medically frail, in which case, a simple technique such as an STSG is the most appropriate choice. In medically stable patients, a radial forearm free flap may provide a more appropriate reconstruction option. Although both techniques are effective, the history may impact my decision. I have found that patients with a history of betel nut use tend to suffer from scar contracture when a skin graft is used. In contrast, the radial forearm reconstruction provides a source of tissue that is less inclined to contract. A history is often helpful in identifying such factors that may influence your decisions on reconstructive approach.

A thorough physical examination should then be undertaken focusing on depth of the tumor involvement as well as the local tissues affected by the cancer, such as bone, orbit, ear, and other subsets of the oral cavity and oropharynx.

After a history and physical is obtained, a diagnosis is necessary, and this can be accomplished with a punch biopsy or an incisional biopsy. Once the diagnosis is established, staging, as is done for any cancer of the oral cavity, must be performed. This will allow determination of the best oncologic treatment and planning for possible reconstructive options. Laryngoscopy may be needed to determine the anatomic extent of the tumor. Since the buccal mucosa is so thin and the area is often secondarily involved, some form of imaging is helpful in determining the anatomic extent of the tumor. Both CT and MRI have been used, and whichever modality is used depends on the preference of the surgeon and the institutional bias.

The cheek is considered to extend from the inferior border of the mandible superiorly to the inferior orbital rim, although some surgeons will consider the superior extent to be a line drawn from the level of the brow to the superior attachment of the helix. Medially, it arises at the lateral aspect of the nasolabial line and extends to the preauricular area. Considered as an anatomic subunit, the cheek is composed of skin, subcutaneous tissue, muscle, and the buccal mucosal lining on the inside of the oral cavity.

The areas of interest are the buccal adipose tissue, which is the deepest layer and is separated from the oral cavity by a thin layer of buccal mucosa. The only nonneurovascular structure that passes through this area is the parotid duct. This structure courses through the cheek, penetrating the buccinator muscle. The papilla of Stensen duct can be seen opposite the second maxillary molar. The anatomical structures involved in the defect will help to dictate what type of reconstructive procedure is performed. Composite tissue loss will mandate reconstruction using a composite tissue flap.

Sensory supply to the cheek is provided primarily by the second and third divisions of the trigeminal nerve; the mental nerve and the infraorbital nerve are the terminal branches. There is a marked degree of overlap and should one of these sensory nerves be severed or interfered with, ingrowth from the adjacent dermatome will allow for recovery of sensation to a great degree. The superficial facial muscles are supplied by the seventh cranial nerve as it exits the parotid gland.

Finally, the arterial supply comes mainly through the external carotid artery via the facial artery. Venous drainage is by way of the anterior facial vein into the internal jugular venous system. The vascular supply is richly anastomotic with connections from deeper structures and from the contralateral vasculature. Ligation of major vessels, such as the facial artery bilaterally, will not have a detrimental effect on healing.

The function of the cheek and its musculature is to assist in deglutition and vocalization. Its role in deglutition is multifold. The ability to open one’s mouth fully without any degree of trismus depends on the integrity of the internal lining of the buccal mucosa. We usually think of trismus as involving the muscles of mastication. However, in patients who are missing a large portion of the internal lining of the buccal mucosa, the maxilla–mandible complex will not be able to separate and function normally. Anything that affects this relationship will cause trismus because of scar formation. Evaluation of the neck is critical since frequently metastases to the cervical lymph nodes are present. A neck dissection is usually required, which may impact the reconstructive options or techniques.

Reconstruction of the buccal mucosa can be classified into three categories: (1) Lesions involving the buccal mucosa only; (2) lesions involving the buccal mucosa, the buccal adipose tissue, and contiguous structures; and (3) full-thickness cheek lesions or large lesions or lesions that infiltrate the skin.

The contraindications to using this technique for reconstruction of the buccal defect are limited to defects that involve extensive mandibular defects. These defects often require a vascularized osteocutaneous free flap.

Occasional small cancers of the buccal mucosa are encountered, and because of the looseness of the buccal mucosa and the redundancy of the tissue, primary reconstruction or reconstruction using a local advancement flap to the buccal mucosa can be used. Areas of up to 3 × 3 cm usually will heal quite well without any trismus developing.

STSG can be used in many patients. Meshed or not, these grafts are sewn in and held in place with a bolster for 5 days, and in my practice, the take rate of an intraoral skin graft has been found to be acceptable without an intraoral bolster. In recent years, more and more of these patients are presenting with deeper lesions that will need to be or have been radiated. In this circumstance, I have found that an STSG is not adequate. It will often still scar over. Other forms of reconstruction must be considered. This also holds true for patients who are going to undergo postoperative radiation. The skin graft will often shrink a great deal after being radiated, and trismus may result.

Lesions of the buccal mucosa are usually squamous cell carcinoma. In the majority of cases, the buccal mucosa is involved secondary to a cancer arising in another anatomic subsite in the oral cavity. Consequently, the reconstruction of the buccal lining must take into consideration the retromolar trigone, the mandible, or the anterior floor of the mouth lesion. In the majority of these cases, free tissue transfer is used whether it is with bone reconstruction or simply a soft tissue reconstruction, and the reconstruction of the buccal mucosa is addressed at that time.

For the patient who has been previously radiated or had an extensive resection of the buccal mucosa, reconstruction with surfacing of the area with a thin fasciocutaneous free flap is often warranted. The radial forearm flap has been my preferred method of reconstruction due to the supple three-dimensionally pliable thin tissue. The size is usually adequate for reconstruction in both a superior–inferior as well as an anterior–posterior dimension. If the tissue turns out to be too thick or the volume is too heavy with subsequent “chewing” on the flap, it can always be debulked and revised at a later date. The anterior lateral thigh flap as well as the latissimus muscle flap with STSG have been used in reconstructing these defects. These flaps offer a larger surface area than the forearm flap but can be too bulky and limit the function of the reconstruction, but are good alternatives in settings where increased bulk is needed, that is, reconstruction of the tongue. Careful attention must be paid to the condition of the donor site in order to rule out prior injury, radiation, cutaneous lesion, or infection. An Allen test must be done to evaluate the collateral circulation.

When reconstructing the defect in the buccal mucosa with a free tissue transfer, it is important to consider the size of the defect (Fig. 4.1) and the pliability of the transferred tissue and to ensure that adequate tissue is harvested and inset in order to prevent posttreatment trismus (Fig. 4.2). When harvesting the flap, an additional 20% is added to the size of the defect in order to ensure that adequate amount of tissue is harvested. The flap is secured to the surrounding mucosal defect with a running 3-0 Vicryl (polyglactin 910, Ethicon) suture (Fig. 4.3).

FIGURE 4.1 Cancer may arise from the buccal mucosa but more frequently arise from the alveolus or tongue and extend onto the buccal mucosa. The defect should be carefully measured to design the flap appropriately.

FIGURE 4.2 The radial forearm free flap is designed to accommodate the defect.

FIGURE 4.3 The flap is sutured into the defect with mild redundancy to prevent trismus as the tissue contracts during healing.

The vascular pedicle is typically positioned in the ipsilateral neck, and a microvascular anastomosis with a running 9-0 Nurolon (Nylon, Ethicon) suture is performed on the arterial system. The facial artery is preferred given its location, size, and geometry. The venous anastomosis is accomplished with a venous coupling device (Synovis), although there are occasions given the final flap/pedicle geometry or size mismatch of the veins that a sutured venous anastomosis is required. One or two implantable Dopplers are then placed on the arterial system, venous system, or both for continuous monitoring of the vascularity of the free tissue transfer.

Postoperatively, the patient should be NPO for 1 week unless the patient has received radiation in which case, I recommend 2 weeks.

Complications include flap failure or fistula. Both are rare, but both may pose a significant problem when they occur. Other complications include donor site morbidity or scar contracture leading to trismus.

Lesions of the buccal mucosa involve a multitude of differing pathologies and surgical technique. The cheek plays an essential role in one’s perception of oneself as well as the physiologic process of chewing and speaking. Reconstruction of the majority of defects is adequately performed with local regional tissue transfer that allows for excellent cosmetic and matching with functional results. Occasionally, one will encounter a patient who has extensive surface area defect in a previously radiated field that is not amenable to local tissue movement so that free tissue transfer is required. Through-and-through tissue defects of the cheek and those involving composite tissues of the mandible or maxilla require free tissue transfer for reconstruction, and patients can oftentimes be rehabilitated with adequate cosmesis and function.

• The ultimate reconstruction of a buccal mucosal defect should offer enough tissue to reconstruct the defect, vascularized as well as innervated tissue, and rapid return of function, at the same time maintaining normal oral competence and minimal donor site morbidity.

• Each reconstructive decision is based on the patient’s preoperative goals and function as well as his or her projected posttreatment function.

• Appropriate evaluation and planning of the reconstructive procedure must be performed prior to surgery.

• If only internal lining is required, primary closure, local rotational flaps, or thin pliable free flaps should be considered depending on the size of the defect.

• Larger composite resections and through-and-through defects will require free tissue transfer.

• Remember to reconstruct the inside dimensions as close to the original defect size whenever possible. But also consider that it is easier to debulk a large soft tissue flap than it is to take care of the complications (wound breakdown, fistulas, or stenosis) resulting in too little tissue to repair the defect.

• Postoperative radiation therapy is one of the most effective means of debulking a flap, so it is important to take into consideration the overall oncologic treatment of each patient.

• Patients with cancer of the head and neck require a multidisciplinary team to ensure not only proper treatment of their cancer but also their posttreatment function. Speech therapy, physical therapy, and dental care are all essential components of the overall care of these patients.

• If the free flap is not of adequate size, trismus as a result of contracture may ensue.

• If the defect and reconstruction involve the parotid duct, it is important to marsupialize the duct to prevent parotitis.

• Standard head and neck surgery set

SUGGESTED READING

Alvi A, Myers EN. Skin graft reconstruction of the composite resection defect. Head Neck 1996;18(6):538–543; discussion 543–544.

Chhetri DK, Rawnsley JD, Calcaterra TC. Carcinoma of the buccal mucosa. Otolaryngol Head Neck Surg 2000;123(5):566–571.

Ducci Y, Herford A. The use of a palatal Island flaps as an adjunct to microvascular free tissue transfer for reconstruction of complex oromandibular defects. Laryngoscope 2001;111:1666.

Deleyiannis FW, Dunklebarger J, Lee E, et al. Reconstruction of the marginal mandibulectomy defect: an update. Am J Otolaryngol 2007;28(6):363–366.

Girod D, Sykes K, Jorgensen J, et al. Acellular dermis compared to skin grafts in oral cavity reconstruction. Laryngoscope 2009;119:2141.