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. We favor the standard combination of cefazolin and metronidazole, and reserve clindamycin for patients with penicillin allergy. Although ampicillin with sulbactam and single coverage with cefuroxime (second-generation cephalosporin) or cefotaxime (third-generation cephalosporin) have been found effective, we do not routinely use them in uncomplicated cases. A short 48-h postoperative course of parenteral prophylaxis is sufficient in routine cases and minimizes the risk of bacterial resistance, superinfection, and antibiotic-associated colitis. Clindamycin mouth rinses have been shown by Kirchner and Sasaki to reduce levels of both aerobic and anaerobic bacteria significantly and are usually started on postoperative day 1 in patients who have undergone oral cavity procedures.
Patients with a recent history of alcohol abuse should receive postoperative thiamine, folate, and vitamin B12 supplementation. For patients who continue to drink actively up to the time of operation, aggressive delirium tremens prophylaxis should be initiated. We typically administer benzodiazepines, either as a standing dose or as needed, depending on the patient's preoperative level of alcohol consumption.
Initial preoperative assessment of nutritional status includes weight (loss of >10% ideal body wt is significant), albumin, and protein levels. Patients with poor nutrition can undergo counseling about adequate vitamin supplementation and the use of high-protein or high-calorie nutritional supplements. For patients who are significantly malnourished or dehydrated, we place a nasogastric tube preoperatively and commence tube feedings. We do not routinely employ preoperative gastrostomy tube placement, except for those patients in whom we anticipate prolonged aspiration or postoperative dysphagia. Postoperative nutritional status is monitored with weight gain and serum prealbumin levels, which are thought to be a more sensitive indicator of nutritional status than albumin alone.
Cardiopulmonary status should be maximized with maintenance of hematocrit ideally above 30%. Although the selective use of perioperative blood transfusions and beta blockers for cardioprotective effect are advocated by some surgeons, they remain an area of debate. In patients with free flaps, vasocon-strictive agents should be avoided. In addition, the threshold for transfusion is kept much higher (hematocrit approximately 25%), primarily given concern for increasing viscosity of blood. Diabetes should be followed closely with tight perioperative control of blood sugar levels and with awareness maintained of the correlation with vascular disease which may impact on flap survival and wound healing. Pulmonary status should be evaluated fully with pulmonary function tests and preoperative arterial blood-gas levels in patients for whom there is concern about persistent postoperative aspiration or chronic ventilator requirement. Subclinical hypothyroidism may be associated with poor wound healing; however, we do not routinely obtain thyroid function tests preoperatively unless the patient has symptoms of hypothyroidism or a history of radiotherapy to the head and neck. Patients with chronic steroid use are started on preoper-ative vitamin A supplementation to aid in wound healing, as shown in studies by Hunt et al.13 Finally, some consideration should be given to the patient's age. Although elderly patients undergoing major resection have complication rates similar to those of younger patients, they suffer from more severe medical conditions thus increasing the hazards of any operation.
In all patients, careful handling of tissues and thoughtful planning of skin incisions are important for adequate wound healing. They are particularly important in patients who have previously been irradiated. Care should be taken to preserve the vascular supply to the skin flap and to design the flap closure away from the carotid artery or underlying mucosal closure. Linear incisions paralleling major vessels should be avoided, and may be accomplished with an inverted Y-incision or modifications of the apron flap. Incisions in previously operated patients should use prior skin incisions to prevent devascularization of skin islands.
Meticulous hemostasis is needed and suction drains should be placed to diminish dead space, promote apposition of tissue, and decrease hematoma formation, all of which promote uncomplicated healing. Ideally, the drains should be placed away from an unprotected carotid artery. We usually leave drains on high wall suction until the output is <30 ml over 24 h. Continued assessment of drain function and drainage quality (serosanguinous, bloody, chylous) should be performed to assist in determining the appropriateness of drain removal.
In patients who have undergone previous irradiation or brachytherapy, coverage of underlying vessels or microvascular anastomosis with vascularized soft tissue should be considered. To protect the exposed and radiated carotid artery, vascular-ized muscle flaps from the levator scapulae, digastric and mylo-hyoid muscles, or prevertebral fascia can be used for local coverage. Dermal grafts can also be used; however, no definitive improvement in fistulization rates have been seen with their use. Local muscle flaps, such as the sternocleidomastoid, or muscle flaps from areas distant to the radiated fields, such as the pec-toralis myocutaneous and trapezius muscle flaps, can also be transposed to cover the carotid artery and support the pharyngeal closure. The pectoralis myocutaneous flap, in particular, has become the workhorse flap in head and neck surgery, largely because it is rapidly harvested and easily transposed into most defects. In addition it provides excellent coverage for vascular structures, protects the pharyngeal closure, replaces lost epithelial lining or compromised neck skin, and provides well-vascularized tissue coverage.
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