FIGURE 34.1 A. Diagram of forearm flap tubed to recreate the hypopharynx. The pharyngeal closure and microvascular anastomosis can be seen on the right. B. Surgical photograph similar to the diagram on the right side of (A). Two venous and one arterial anastomoses are seen. SCM indicates sternocleidomastoid muscle. Other anatomic landmarks are as designated. The pliable forearm flap is being held up to demonstrate the initial suture line on the right pharyngeal wall. In the photograph, there is a strip of mucosa posteriorly, while the prior diagram shows a circumferential reconstruction.

This chapter focuses on the technical details of reconstruction of the hypopharynx with a radial forearm free flap.

HISTORY

Unfortunately, the early symptoms of cancer of the hypopharynx are often nonspecific and include a foreign body sensation in the throat, mild discomfort with swallowing, or mild otalgia. These are generally persistent and continuous, rather than intermittent, and gradually become worse over time. It is common for patients to be misdiagnosed by primary physicians as suffering from pharyngitis or reflux and to be treated with multiple courses of antibiotics and antireflux therapies, prior to making the correct diagnosis, particularly since the presence of superinfection, combined with a placebo effect may lead patients to report improvement after initial antibiotic therapy.

Patients are usually diagnosed with advanced stages of cancer, by which time the patient has developed severe odynophagia, dysphagia, and/or otalgia, which can be unilateral or bilateral depending on the location of the cancer. Some patients will present with cervical adenopathy as the primary complaint, and 65% to 75% of patients will have clinically obvious metastasis to cervical lymph nodes at the time of presentation. Severe dysphagia and inability to eat solids can be a sign of involvement of the cervical esophagus. Exophytic hypopharyngeal cancer can cause the classic “hot potato” voice due to a change in the hypopharyngeal resonance, and direct invasion of the larynx can lead to fixation of the vocal cords, with hoarseness and breathiness of the voice, as well as chronic aspiration. Halitosis, inability to manage secretions, bloody secretions, hemoptysis, and hematemesis are all hallmarks of advanced cancer of the hypopharynx.

The vast majority of patients with cancer of the hypopharynx will have a significant history of tobacco and alcohol abuse. Unlike the nearby oropharyngeal subsite, cancers in this area are rarely related to HPV exposure. Due in part to delays related to alcohol abuse or poor access to medical care, in combination with dysphagia and anorexia related to the cancer itself, some patients who have hypopharyngeal cancer will suffer severe weight loss and present in a state of marked malnutrition, which can greatly compromise healing and the ability to withstand cytotoxic therapies.

PHYSICAL EXAMINATION

When the patient presents to the otolaryngologist with a history of symptoms referable to the hypopharynx, the first step is a complete examination of the head and neck, including palpation of the neck, mirror examination of the larynx and hypopharynx, and in most cases, an office fiberoptic laryngopharyngoscopy is a part of the physical examination. In many cases, an irregularity in the mucosa will be seen that can be exophytic or infiltrative. Raised areas, with a combination of erythroplasia and blanched necrotic tissue, may be identified. More infiltrative cancers can be more difficult to detect visually but can be characterized by ulceration and edema of the overlying mucosa. Lesions may be present on the posterior wall of the hypopharynx above the level of the arytenoids or on the medial, anterior, or lateral walls of the piriform sinuses. Cancers of the postcricoid area or the apex of the piriform sinus cannot be seen directly on routine fiberoptic nasopharyngoscopy and laryngoscopy, but edema and pooling of secretions are usually present. A Valsalva maneuver may open the piriform sinus and assist in the visualization of a tumor. The diffusion of office transnasal esophagoscopes, with the ability to insufflate and suction without requiring specific scheduling and sedation, allows the surgeon to better visualize the more distal lesions at the time of the initial office evaluation. Fiberoptic esophagoscopy, however, can miss a lesion in the piriform sinus or postcricoid area due to loss of visualization at the constricted area of the cricopharyngeus muscle.

Cancer of the medial wall of the piriform sinus commonly extends submucosally at the deep margin into the paraglottic space, and fiberoptic laryngoscopy may reveal thickening or edema of the aryepiglottic folds and vocal fold paralysis. Cancers of the postcricoid area will typically produce edema of the arytenoids and may also lead to fixation of the vocal folds.

Palpation of the neck will allow the surgeon to assess the number of pathologic lymph nodes present, their size, unilaterality versus bilaterality, and whether there is reduced mobility or fixation that portends involvement of vascular structures, cranial and spinal nerves, and deep cervical muscles. The retropharyngeal lymph nodes may also be involved.

INDICATIONS

Laryngopharyngectomy, with cervical lymphadenectomy and reconstruction of the pharynx with a radial forearm flap, is indicated for advanced cancer of the hypopharynx. For early stage I and II cancer, partial laryngectomy, radiation, or combined chemoradiation are often excellent options. For stage III cancer, combined chemoradiation is commonly considered, and for certain tumor anatomies, stage III (T3N0) lesions might be considered for extended partial laryngectomy. However, for advanced T4 cancer of the hypopharynx, and for recurrent cancer after previous treatment, laryngopharyngectomy is usually indicated.

Radial forearm flaps are contraindicated in patients with inadequate circulation to the hand, as sacrifice of the radial artery in such a case would lead to vascular insufficiency and even gangrene of the hand. The Allen test is used to assess this on physical examination, with concurrent compression of the radial and ulnar arteries, followed by release of the ulnar artery and evaluation of revascularization of the hand by assessing color. When the Allen test is equivocal, the test can be repeated with the assistance of the Doppler ultrasound to assess blood flow and pressure in the fingers (digital Doppler-assisted Allen test). If a patient fails his or her Allen test, other reconstructive options must be considered. Generally, the pectoralis major flap, anterolateral thigh flap, or lateral arm flap provide reasonable alternatives.

CONTRAINDICATIONS

This procedure represents a major intervention and can take 10 or more hours to accomplish. Patients with severe comorbidities, such as severe cardiovascular disease, marked malnutrition and debilitation, end-stage renal or pulmonary disease, or dementia, may not tolerate such prolonged surgery.

PREOPERATIVE PLANNING

Fine Needle Aspiration

When patients present with palpable cervical lymph adenopathy and the primary cancer is not well visualized, fine needle aspiration and cytologic analysis can be used to establish the diagnosis of cancer and justify imaging and endoscopy. It is not mandatory if biopsy of the primary cancer is planned.

Endoscopy

The way to most accurately diagnose cancer of the hypopharynx is direct laryngoscopy with biopsy under general anesthesia. Failure to visualize a lesion on office examination should not dissuade the surgeon from proceeding with direct laryngoscopy in the presence of unexplained, persistent foreign body sensation in the throat, discomfort with swallowing, or otalgia. Typically rigid or flexible esophagoscopy is also performed to rule out direct extension or second primary cancers involving the esophagus. Screening bronchoscopy may also be performed. The risk of second primary cancers of the upper aerodigestive tract, esophagus, or lungs is estimated at 10% to 20% and is a particularly significant issue for hypopharyngeal cancers relative to other anatomic subsites in the head and neck. Early second primary cancers are not always seen on imaging and may occasionally be detected on careful endoscopy.

A biopsy is mandatory in order to establish a diagnosis and potentially recommend treatments that are radical or toxic. The biopsy is usually obtained with a cup forceps, and infrequently, other microsurgical instruments, such as sickle blades, microscissors, or lasers, are needed to perform incisions and obtain biopsies of submucosal or cartilaginous tumors, or indurated cancers that are difficult to enter with a cup forceps. Generous biopsies, including some performed at the interface between the cancer and normal adjacent tissue, should be performed, in order to ensure that sufficient viable tissue is obtained to make an appropriate pathologic diagnosis.

Head and neck oncologic surgeons will commonly receive patients who have already undergone direct laryngoscopy and carry a biopsy-proven diagnosis of cancer, most commonly squamous cell carcinoma. In this situation, the surgeon may develop a relatively complete understanding of the anatomy of the lesion, based on office nasopharyngoscopy or transnasal esophagoscopy, and imaging studies, and may elect to repeat the direct laryngoscopy immediately prior to ablative surgery, during the same intervention. In other cases, a repeat direct laryngoscopy and esophagoscopy at an earlier date may be indicated in order to ascertain whether circumferential involvement or esophageal involvement is present, and better plan the reconstruction, as well as to ensure adequate staging and make proper decisions regarding the use of chemotherapy and radiation as alternative approaches in the management of these cancers.

Imaging Studies

A barium swallow may be useful in a patient with symptoms of dysphagia in whom a visible lesion is not present, although in a setting of high suspicion, the surgeon will often elect to bypass this study and proceed to direct laryngoscopy and esophagoscopy. A negative barium swallow does not exclude cancer in the hypopharynx, and results of such a contrast study should be interpreted with caution.

When the diagnosis of cancer of the hypopharynx is strongly suspected or confirmed, an anatomic imaging study, most commonly a contrasted computerized tomography (CT) of the neck, is indicated in order to delineate the anatomy of the cancer, including its superficial and deep extension. The presence of cartilage destruction in the larynx is best identified on CT. The extent of invasion of larger metastatic nodes and the number of suspicious nodes can also be determined. Magnetic resonance imaging with or without gadolinium contrast can be used when the patient is allergic to iodine, or as a complementary study to assist in answering specific questions, such as the presence of invasion of the retropharyngeal fascia or vascular structures and the presence of gross perineural invasion, findings that may predict an inability to completely clear the resection margins of cancer.

Positron emission tomography–computerized tomography (PET–CT) can be useful in determining whether equivocal lymph nodes palpated or seen on imaging actually harbor malignancy. It can also identify mediastinal lymph node metastases, pulmonary nodules, and other distant metastases. However, false positives related to inflammatory processes are common, and the surgeon must be skeptical in the interpretation of PET and utilize anatomic imaging and clinical knowledge to make appropriate decisions regarding treatment. Alternatively, a CT of the thorax with contrast will image the highest risk sites, the mediastinum and lungs, for the presence of distant metastases.

Histopathology

More than 95% of malignant hypopharyngeal tumors are squamous cell carcinomas. In addition to the classic variant, subtypes of squamous cell carcinoma occasionally are described, such as adenosquamous, acantholytic, basaloid, spindle cell, papillary, and nasopharyngeal type (lymphoepithelial). Most of these behave similarly to classic squamous cell carcinoma. Verrucous carcinoma is well differentiated and indolent and most commonly is treated surgically in order to avoid purported risk of transformation to more aggressive histologies when treated with radiation therapy. It grows with pushing borders and rarely metastasizes. Verrucous carcinoma is infrequent in the hypopharynx and occurs most commonly in the oral cavity and occasionally in the larynx. Acantholytic and papillary squamous cell carcinomas can be less infiltrative than the classic variant. Nasopharyngeal-type carcinoma occurs rarely in the hypopharynx, and while high in grade, these cancers are characterized by exquisite sensitivity to chemotherapy and radiation.

Nonsquamous carcinomas, such as mucoepidermoid carcinoma and neuroendocrine carcinomas, can occur. Their behavior is often predicated by their grade, which can be high, intermediate, or low. Low-grade neuroendocrine carcinomas are referred to as carcinoid tumors and are much more common in the lower gastrointestinal tract. Sarcomas and lymphomas can also occur in the hypopharynx but are exceedingly rare.

SURGICAL TECHNIQUE

The patient is brought to the operating room and placed under general endotracheal anesthesia. If the presence of exophytic cancer makes standard intubation difficult, awake fiberoptic intubation is an option, but more commonly awake tracheostomy is performed to allow for induction of anesthesia, since a tracheostomy is planned as part of the procedure. After induction of anesthesia, the eyes are protected with tape and hard goggles, pressure points are padded, and the head of the bed is rotated 180 degrees away from the anesthesia station. Dynamic compression stockings are placed for the prevention of pulmonary embolus. Direct laryngoscopy is then performed to confirm the anatomy of the cancer. Rigid esophagoscopy and bronchoscopy are also performed. The presence of esophageal involvement below the cervical inlet, or involvement of the inferior aspect of the trachea, may make the planned procedure impossible; alternatives, including gastric pull-up, sternectomy, mediastinal tracheostomy, or nonsurgical options, may need to be considered. Appropriate preparation is performed with antiseptic solution and draping of the head and neck, forearm, and pectoral area (for a possible backup flap). I begin the open procedure by prepping and draping the patient to the neck as well as to the forearm.

The resection, tracheostomy, and neck dissections are open surgical procedures, and there are a wide variety of styles that surgeons have in accomplishing these procedures. I favor a meticulous dissection with the use of scalpel, bipolar cautery, DeBakey forceps, Gerald forceps with teeth, and fine Jamison scissors. I use electrocautery for the less delicate portions of the dissection, and ties or clips for control of vessels.

Elevation of the flap involves clipping multiple vascular branches that come off of the pedicle, and automatically reloading clips will expedite this procedure. A tourniquet is usually used during flap elevation to temporarily maintain hemostasis at the donor site. For the microvascular anastomosis, I have a tray of shorter microvascular instruments and a tray of longer microvascular instruments, including jeweler’s forceps, microvascular needle holders, single and frame sizes 3 and 4 arterial and venous clamps, larger vascular bulldog clamps, and 9-0 nylon on a V100-3 needle. The Synovis GEM microvascular anastomosis coupler can be used for the venous anastomosis if adequate-sized matching vessels are found, and this can reduce operative time significantly.

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