Management of a Tracheocutaneous Fistula and Depressed Scar

Introduction

A tracheocutaneous fistula (TCF) is a sequela of a tracheostomy and is usually associated with an unsightly depressed tracheostomy scar ( Fig. 23.1 ). Formation of this fistula is predicated on squamous epithelium migrating from the skin into the trachea, forming an epithelial interface with the mucosa of the trachea, and thereby creating a true fistula that cannot close spontaneously. Marked separation of the strap muscles associated with a prolonged indwelling cannula, infection, and wasting of subcutaneous tissue due to poor nutrition and weight loss are important factors predisposing to the development of a depressed scar and fistula. These features facilitate epithelial migration toward the tracheal mucosa along the tract formed by the tracheostomy cannula. White and Smitheringale suggest that epithelial migration of skin into the trachea and extensive cicatricial resolution of chronic granulation tissue result in the formation of a dense connective tissue sleeve based around the entire opening of the tracheal stoma.

During the performance of a tracheostomy, the strap muscles are retracted laterally, and the cannula is inserted. In a patient who has had a cannula in place for a prolonged period, infection and fibrosis occur and the strap muscles are scarred into a position lateral to the tracheostomy. When the patient is eventually decannulated and the stoma heals by secondary intention, the skin heals directly to the trachea, thus forming a depressed scar due to the separation of the strap muscle with or without a TCF. The relationship between the duration of tracheostomy and the development of a persistent fistulous tract has been well established, with a fistula rate of 50% identified in patients with a cannulation time of longer than 1 year. Other risk factors proposed include previous neck radiation or tracheostomy. Interestingly, stomal maturation has not been found to be a risk factor for formation of a TCF.

Persistence of a TCF may lead to increased morbidity, particularly in patients with limited pulmonary reserve, which is of particular concern in children. Eaton and colleagues stated that a persistent TCF may be a source of considerable morbidity because of problems with poor hygiene, aspiration, respiratory infection, and associated difficulty with voicing. In addition to functional problems with the TCF, unsightly scars often follow tracheostomy decannulation. With the skin directly adherent to the trachea at the site of the TCF, every time the patient swallows the skin moves up and down, which attracts unwanted attention. Many emergency tracheostomies are still carried out through a vertical incision, which itself may result in an unsightly scar or a keloid.

Several methods for closure of a TCF have been described, including primary closure, fistulectomy with primary closure in layers, and fistulectomy with healing by secondary intention. When a fistula is too large to close by secondary intention, a surgical procedure is necessary. Closure of a TCF was reported as early as 1934 by Jackson and Babcock. They used a lined bipedicled flap reinforced with conchal cartilage. Pressman described the repair of a depressed tracheostomy scar by detaching and transposing the origins of the sternocleidomastoid muscle into the defect. Others have suggested the use of sternohyoid muscle rotational flaps, subcutaneous Z-plasty, turnover flaps, and V-Y advancement flaps. For very small fistulas without concern for cosmesis, chemical or electrocautery has been described.

Our technique for correction of the depressed scar emphasizes restoring the natural anatomic position of the strap muscles in the midline. This key feature has eliminated the need for the aforementioned procedures. Kulber and Passy have described a similar technique that prevents reattachment of the skin to the trachea by reapproximation of the strap muscles in the midline.

Key Operative Learning Points

• Patients should be evaluated endoscopically to ensure that the airway is patent before closure of a TCF.

• The key feature of the operation is dissecting the strap muscles free of scar tissue and the trachea and restoring the normal anatomy by reapproximating the strap muscles in the midline. This reinforces the closure in patients with a TCF and eliminates the depressed scar in all patients.

• Failure to thoroughly free the strap muscles from scar tissue and the trachea and to reapproximate the muscles in the midline will result in persistence of the depressed scar.

• Failure to provide airtight closure of the fistulous tract and provision of an inner epithelial lining will result in recurrence of the fistula.

• TCFs are colonized by bacteria, so perioperative antibiotics should be given to prevent infection.

• Patients, particularly those in the pediatric age group, may experience respiratory distress after closure of a TCF.

• Children undergoing closure of a TCF should be monitored in the intensive care unit after the procedure, because airway distress may be a complication of this procedure.

• Adult patients should be observed in the hospital overnight to ensure that the airway is stable.

Preoperative Period