Partial Pharyngectomy

Introduction

The hypopharynx is the inferior-most portion of the pharynx, bounded by the oropharynx superiorly and the esophagus inferiorly. The hypopharynx is intimately related to the larynx, both anatomically and functionally. Anatomically, the hypopharynx extends from the base of the vallecula down to the apices of the piriform sinuses and the inferior border of the cricoid cartilage. For purposes of classification, the hypopharynx is divided into three subsites: the piriform sinuses, the posterior pharyngeal wall, and the postcricoid area. The mucosa of the hypopharynx is continuous with that of the larynx, and cancers that originate in one site frequently spread to the others. Functionally, the hypopharynx and larynx are responsible for coordinating the competing tasks of airway maintenance and deglutition.

Squamous cell carcinoma (SCCA) is the most common malignancy presenting in the hypopharynx and usually presents at an advanced stage. Alcohol and tobacco are strong risk factors, as with other cancers of the head and neck.

Due to the rich lymphatics of the pharynx, cervical metastases are common with hypopharyngeal primaries, and over two-thirds of patients present with stage III or IV cancer. Perhaps because of this, prognosis is often poor despite aggressive treatment—hypopharyngeal SCCA has the worst prognosis of SCCA at any subsite within the head and neck. The piriform sinus is the most common site for hypopharyngeal cancer.

Traditional treatment for hypopharyngeal SCCA included surgery, usually total laryngectomy with total or partial pharyngectomy, and was followed by postoperative external beam radiation therapy (XRT). However, following landmark studies using chemoradiation with surgical salvage for laryngeal and hypopharyngeal cancers, which showed equivalent survival in the surgical and nonsurgical arms, the use of primary surgical treatment of hypopharyngeal cancer has decreased.

Both surgical and nonsurgical treatments for hypopharyngeal cancers carry significant functional morbidity. Gastrostomy tubes are often required during and after treatment, and swallowing and sometimes airway function following chemoradiotherapy may be permanently compromised, despite a surgically undisturbed larynx ( Fig. 48.1 ).

Given the low cure rates and high rates of functional sequelae, alternatives to laryngectomy and nonsurgical organ preservation continue to be of interest and evolve. Such operations as transoral laser microsurgery (TLM), transoral robotic surgery (TORS), and extended partial laryngopharyngectomy procedures such as SCHLP (supracricoid hemilaryngopharyngectomy) provide palliation and cure rates that rival other treatments and are being revisited for selected lesions.

Key Operative Learning Points

• Small cancers of the posterior wall of the pharynx may be resected transorally or through a suprahyoid pharyngotomy.

• At least 2.5 to 3 cm of pharyngeal mucosa must remain in the transverse dimension after resection in order to close the pharyngeal mucosa primarily.

• Cancer extension across the midline of the posterior hypopharyngeal wall or involving the postcricoid mucosa requires total laryngopharyngectomy with reconstruction.

• Cancers extending to the esophagus cannot be excised and the wound closed primarily.

• Failure to aggressively preserve uninvolved mucosa may preclude primary closure.

• Wound closure under tension due to insufficient mucosa will predispose to wound breakdown, fistula formation, and postoperative dysphagia due to stricture formation.

• Submucosal spread is common in hypopharyngeal cancers, and negative margins must be confirmed by frozen section.

• Patients must understand that although every attempt may be made to perform partial laryngopharyngectomy, intraoperative findings or frozen section pathology may make this impossible. Therefore, patients should be consented for a possible total laryngopharyngectomy.

• Patients with prior radiation or chemoradiation should have pharyngeal closure performed with a vascularized flap either integrated into the remaining pharyngeal mucosa or tubed in the case of total pharyngectomy defect. A pectoralis major flap can be used for closure of the anterior pharynx over remaining mucosa, but a complete pharyngeal defect with discontinuity is best reconstructed with free tissue transfer.

Preoperative Period