A head and neck fistula typically refers to an unplanned postoperative communication between the upper aerodigestive tract and skin. Although this term may also refer to other types of fistulae, such as a tracheal fistula or chylous fistula, this chapter focuses primarily on pharyngocutaneous fistulae. Postoperative fistula formation remains a challenging problem that can be managed only with understanding of causative factors, diagnosis, methods of prevention, and treatment options.

All patients undergoing surgery of the upper aerodigestive tract are at risk of pharyngocutaneous fistula, even in the hands of the most technically competent surgeons. The first laryngectomy carried out by Billroth in 1873 was complicated by a large pharyngocutaneous fistula and eventual death. The current incidence of pharyngocutaneous fistula after laryngectomy varies widely in the literature. Giordano et al.1 report an average fistulization rate of 17%, whereas Weissler² ranged from 9% to 21%, and Papazoglou et al.³ note an incidence varying between 2 and 66%.

Causative Factors

Several factors are thought to cause or predispose to fistula formation. They are most easily classified into local and systemic factors with several subdivisions in each group. Because preventing a fistula is much less costly and morbid than treating one, identifying and minimizing these risks helps promote uncomplicated wound healing and prevents fistula formation.

LOCAL FACTORS

The most significant factor in fistula formation is an associated wound infection. The oral cavity, pharynx, and larynx are clean contaminated surgical sites, exposed not only to saliva, but also to tracheal, pulmonary, and regurgitant gastric secretions. Kirchner at al.⁴ have shown bacterial counts in saliva of irradiated subjects to be as high as 10⁵/ml. Others have shown decreased fistula rates when dental prophylaxis precedes tumor resection. As shown by Weber et al.,⁵ wound infection rates are 30 to 80% without antibiotic prophylaxis and decrease to about 5 to 30% with appropriate antibiotic administration. Modern surgical techniques and preoperative administration of prophylactic antibiotics have been critical factors in preventing wound infections and fistula formation in head and neck surgery.

Gastroesophageal reflux has been identified as an important factor in many inflammatory and neoplastic disorders of the aerodigestive tract. Although no definitive studies have shown a correlation between reflux and fistulization, Seikaly and Park⁶ showed a decreased rate of fistulae formation in patients treated with a postoperative antireflux regimen. We routinely maintain intravenous H₂blocking agents until gastric feeding can be started via tube feeds.

The effect of preoperative radiation therapy on fistula formation remains controversial. Studies reported by Dedo et al.,⁷ Mendelsohn et al.⁸ and others report that preoperative radiation predisposes to fistula formation by damaging tissue, decreasing vascular perfusion, and delaying healing. However, other studies, including Thawley⁹ and, more recently, Fradis et al.¹⁰ and Soylu et al.,¹¹ concluded that radiation does not correlate with the likelihood of fistulization. Studies of patients undergoing brachytherapy show wound complication rates ranging from 10% to 50% in patients undergoing either brachytherapy as part of their initial cancer treatment or combined surgery–brachytherapy for salvage. In our experience, prior full-course radiotherapy (>5000 cGy) and brachytherapy have a detrimental effect on wound healing and are considered risk factors for compromised healing and fistulization. As a general practice, a trial of oral intake that might routinely take place on postoperative day 7 is deferred until postoperative day 10 in the previously irradiated or implanted patient.

Another well-established cause of fistula formation is tight wound closure that places undue tension on the suture line. Advanced T3 and T4 tumors have a higher incidence of fistula formation, due primarily to the added resection of the pharyngeal wall and consequent tighter closure. Similarly, pharyngocutaneous fistulae are more common with total laryngectomy or partial laryngopharyngectomy than with supraglottic resection due to extension of the resection to include the pyriform area. Although the extent of oncologic resection is not within the reconstructive surgeon’s control, reconstructive efforts should strive to minimize tight closure. If the pharyngeal closure is tight enough to impair the outflow of the swallowed bolus, saliva will follow the path of least resistance and may leak through the suture line during swallowing. Similarly, distal anastomotic stricture in gastric pullup may lead to outflow resistance and cause backup of secretions. The problem of tense closure can be managed by recruiting additional tissue for closure of the pharyngeal mucosa over a nasogastric tube. As shown by Horowitz and Sasaki,11 upper esophageal sphincter myotomy at total laryngectomy significantly decreases peak pharyngeal pressures, minimizing proximal fistulization through the suture line. Clayman and Weber¹² report a 20% fistula rate with gastric pullup reconstruction of circumferential hypopharyngeal defects, with a rate of only 2% with free jejunal transfer—a difference they attribute to decreased tension of closure with free jejunal transfer giving less concern about tethering. At our institution, laryngopharyngoesophagectomy with gastric transposition is more commonly performed than free jejunal transfer, with a fistulization rate of 3%.

The last local predisposing factor in the development of pharyngocutaneous fistula is residual gross or microscopic tumor at the surgical site or resection margins. Residual tumor disrupts the healing process, leads to wound infection, and results in early dehiscence and fistula formation. Fistulae that occur within 1 to 2 weeks postoperatively frequently reflect problems relating to systemic and local factors in wound healing. Those occurring about 2 to 3 weeks postoperatively may also be due to these same factors, however, persistent cancer should also be considered, particularly if the fistula persists despite appropriate management.

SYSTEMIC FACTORS

In addition to the local factors reviewed previously, there are several systemic considerations that impact on a patient’s ability to heal. Many of these systemic factors are related directly to the risk factors that predispose to head and neck cancer itself: heavy alcohol use and smoking. Patients who continue to smoke until surgery often not only suffer from compromised pulmonary status but are at increased risk of wound breakdown due to poor distal vascular perfusion caused by a direct nicotine effect.

Similarly, patients with a history of alcohol abuse are at an increased risk for poor wound healing due to nutritional depletion. For patients who continue to drink actively up to the time of surgery, delirium tremens also poses a concern. The signs of delirium tremens usually begin approximately 48 to 72 h postoperatively and may be life-threatening if unattended promptly. In addition to cardiopulmonary compromise, significant concern is maintained for the physical disruption of the wound by an agitated thrashing patient, particularly in the setting of a tight closure or underlying free flap.

Most head and neck cancer patients present with some degree of malnutrition. Poor oral intake due to mechanical obstruction, and / or chronic alcoholism is common. In this situation, properly diagnosing malnutrition and restoring the patient to a positive nitrogen balance becomes critical.

Other systemic conditions, such as cardiopulmonary compromise, diabetes mellitus, chronic steroid use, hypothyroidism, or other conditions leading to immune system deficiency should also be addressed in the preoperative evaluation and followed closely postoperatively.

Prevention and Optimization

Identifying and minimizing the factors that predispose to fistula formation helps improve the chance of successful wound healing. Since most fistulae are associated with a wound infection, appropriate antibiotic coverage is essential. Studies by Johnson et al. and more recently by Weber et al.⁵ show a marked decrease in wound infection rates with appropriate antibiotic administration. For maximum efficacy, one dose should be given preoperatively so that antibiotics are in the circulation before the skin incision is made. The spectrum of coverage should include oral anaerobes as well as aerobic gram-positive and negative bacteria, including Staphylococcus aureus

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