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.




Fig. 23.1


A tracheocutaneous fistula and depressed scar as a result of long-term placement of a tracheostomy cannula.


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


History of Present Illness





  • Indication for and duration of the tracheostomy




    • With particular attention to whether it was emergent or planned




  • Amount of time since decannulation



  • Previous attempts at repair




    • Previous attempts may decrease the likelihood of success with the currently planned repair. The surgeon will also need to be mindful of the likely presence of increased scar tissue.




  • Associated symptoms




    • Shortness of breath



    • Difficulty with voicing



    • Productive cough



    • Saliva coming through the fistula



    • Dysphagia and/or pneumonia



    • Fistula site infections



    • Cosmetic concerns




  • Past medical history




    • With particular attention to associated cardiopulmonary dysfunction, the need for positive pressure ventilation at baseline for obstructive sleep apnea or other cardiopulmonary disease



    • History of radiation of the neck, diabetes mellitus, and vascular disease may place patients at risk for poor wound healing or persistent fistula




  • Past surgical history




    • Particularly including history of tracheostomy, previous attempts at repair and other surgeries within the neck




  • Social history




    • Tobacco use will impair wound healing and could contribute to the incidence of postoperative subcutaneous or mediastinal emphysema if there is coughing on emergence from inhaled anesthesia




Physical Examination





  • Complete examination of the head and neck




    • Attention to TCF or depressed scar site (vertical or horizontal tracheostomy)




      • Presence and size of TCF



      • Presence of associated keloid or granulation tissue




    • Examination of the neck




      • Other scars within the neck



      • Thyromental distance




    • Examination of the oral cavity and oropharynx may suggest risk factors for obstructive sleep apnea or difficult airway perioperatively.




      • High, arched palate



      • Glossoptosis



      • Mallampati score





  • Flexible laryngoscopy and tracheoscopy should be performed to assess the entirety of the upper airway to the level of the carina to ensure that there are no sources of obstruction.




    • Complications may occur after closure of a TCF, particularly in children, so it is of utmost importance to ensure that the caliber of the trachea is satisfactory before closure. One reason for persistence of the fistula may be that the patient does not have an adequate airway, and the fistula serves as an auxiliary airway. The concern is that once the fistula is closed in such patients, the airway might not be patent enough to permit adequate air exchange.



    • During airway endoscopy, particular attention should be paid to the suprastomal trachea and subglottis, as this is the most common site of granulation formation and stenosis in children.



    • Awake transnasal bronchoscopy can also be performed in-office using a combination of nebulized and topical 4% lidocaine to assess the complete airway dynamically.



    • In children who will not tolerate in-office endoscopy, formal airway endoscopy should be performed at the time of repair.




  • Patients should be able to tolerate occlusion of the TCF for at least 24 hours.



Imaging





  • Computed tomography of the neck (noncontrast) can be considered to evaluate the adequacy of the tracheal lumen, particularly if endoscopy is inadequate.



Indications





  • Patients selected for this procedure have symptoms associated with the fistuous tract or scar, including difficulty with voicing, productive cough, saliva coming out of the fistula, dysphagia and/or pneumonia, fistula site infections, ineffective cough, or cosmetic concerns.



  • The fistula should have been present at least 3 months after decannulation to allow for an adequate opportunity to heal secondarily.



Contraindications





  • Inability to tolerate occlusion of the TCF or airway obstruction noted on endoscopy



  • Active infection at the fistula site



  • Chronic cough



  • Need for positive pressure ventilation (relative contraindication)




    • Polysomnogram should be obtained preoperatively with occluded stoma for patients with known or suspected obstructive sleep apnea (OSA) to assess the degree of OSA. Patients with OSA should be counseled regarding the need for long-term positive pressure ventilation if TCF is closed.



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Apr 3, 2019 | Posted by in OTOLARYNGOLOGY | Comments Off on Management of a Tracheocutaneous Fistula and Depressed Scar
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