What Is The Tracheoesophageal Fistula

Introduction

Tracheoesophageal fistula (TEF) is defined as an abnormal communication between the trachea and the oesophagus. While fistulas can have traumatic or infectious origins, iatrogenic injury after tracheotomy and tracheal intubation, or be caused by tumours, radiotherapy, or acid ingestion, the most common form is congenital¹. The aetiology of TEF is multifactorial, with environmental, genetic, and possibly epigenetic factors involved in its pathogenesis.²

Congenital TEF arises due to an issue in the separation between the trachea and oesophagus during the embryonic period, occurring in the first weeks after conception. The embryo possesses a single organ called the primitive intestine, which, around the fourth week of intrauterine life, gives rise to the tracheoesophageal diverticulum, eventually dividing into the trachea and oesophagus. Consequently, it is common for congenital TEF to be linked with other esophageal malformations,¹ a condition reported in 1 for 2400 to 4500 live births.³ Additionally, the fistula can be associated with anomalies in at least one other organ system, occurring in 46 to 69% of cases, particularly in cardiac, genitourinary, or skeletal/vertebral systems.^4,5,6

However, although rare, representing 4 to 5% of all esophageal malformations and with a prevalence of 1 in every 50,000 to 80,000 live births, congenital TEF occurs in an isolated form.⁷

Classification of the congenital TEF

Anatomically, the isolated TEF, also known as H-type fistulae, always has the tracheal side more cephalic than the esophageal side, resembling more the letter 'N' than the letter 'H'. Therefore, the term N-type fistulae was proposed, reflecting the oblique anatomical course of the fistula more accurately.^8,9

Clinical manifestations

The presence of the fistula can facilitate the passage of saliva or food from the esophagus to the trachea (an organ belonging to the respiratory system responsible for conducting air to the lungs), resulting in clinical manifestations such as cough and cyanosis triggered by feeding, recurrent lung infections secondary to aspiration during feeding, and abdominal distension due to gas accumulation in the gastrointestinal tract, culminating in respiratory failure and even death.^7,10 However, the clinical manifestations vary and depend on the size of the fistula.¹¹

Diagnosis

There is no evidence of prenatal diagnosis for isolated TEF, but polyhydramnios can occur.⁶ About 25% of premature babies are born before completing 37 weeks of gestation.⁹ After birth, despite symptoms being present in more than 82% of cases during the first week of life,⁴ the variability and lack of specificity of the symptoms make the diagnosis of TEF difficult.¹¹ Although symptoms are usually present from birth, they can sometimes be intermittent and may increase or decrease in severity, which can contribute to the delay in diagnosis.² Therefore, a high index of suspicion is important for early diagnosis.¹¹ A multicenter study conducted in Saudi Arabia between 1998 and 2013 reported that 70% were diagnosed within the first 6 months of life and 90% within the first year,¹⁰ but there are reports of diagnoses made around the age of 15 years.⁴

After clinical suspicion, the diagnosis is confirmed through radiological modalities such as contrast esophagogram, video esophagogram, or computed tomography (CT) scan or through endoscopy – such as tracheoscopy.4,7,10 Contrast esophagogram is usually the first-choice technique, but non-invasive diagnostic techniques, such as high-resolution CT scans or magnetic resonance imaging, have been used in premature or unstable babies.⁴ In the contrast esophagogram, low-viscosity contrast is administered through a probe located in the cervical region, and its path is tracked by imaging exams. Considering the specificities of the fistula, such as its oblique shape, thickness (thin fistulas can even hinder the passage of the contrast), movement during the respiratory cycle, and possible presence of secretion, none of the diagnostic tests are 100% sensitive. However, the combined use of contrast studies of the upper digestive tract, bronchoscopy, and chest CT scan improves the detection of TEF.¹¹ Additionally, all these tests also contribute to locating the level of the fistula, aiding in the planning of the necessary surgical correction for the defect.⁴

Preoperative management

The ERNICA Consensus Conference on the Management of Patients with Esophageal Atresia and Tracheoesophageal Fistula, published in 2020, outlined a series of recommendations to be followed from diagnosis to the preoperative period of tracheal malformations. To minimize the risk of aspiration pneumonia, the following measures are emphasized: discontinuation of oral diets, keeping the newborn in an upright position, and continuous (and low-pressure) aspiration of saliva through a probe inserted in the upper esophageal region. Additionally, a thoracoabdominal x-ray should be performed. Preference is given to spontaneous respiratory breathing; however, if the baby requires ventilatory assistance, intubation is recommended, and non-invasive ventilation should not be interrupted.¹²

Care should be initiated to maintain the newborn's temperature, oxygenation, hydration, and protein-caloric intake.¹³ A preoperative echocardiogram is necessary due to the high prevalence of congenital heart disease.¹²

Bronchoscopy can also be used as a preoperative technique and cannulation of the fistula tract, allowing precise identification of the fistula's path during intraoperative procedures.⁴

Surgical treatment

The surgery should be performed when the newborn is stable, preferably electively, during the week and within business hours. Antibiotics should be routinely administered perioperatively, and venous and arterial catheters should be inserted.¹²

The surgical approach can be traditional (also known as open surgery) or minimally invasive. The traditional approach is performed through a thoracotomy, in which a right cervical incision is made with dissection of tissue planes at the base of the neck, isolation and repair of the defect by ligating the fistula, and tension-free closure of both the oesophagal and tracheal sides.⁴

The minimally invasive approach is performed through thoracoscopy using fibre-optic cameras. This technique should be carried out by surgeons with specialized training. Despite having a longer duration than the traditional approach, it has the main advantage of causing fewer musculoskeletal sequelae compared to the conventional approach.¹²

Immediate postoperative period

After surgery, the care to maintain the newborn's temperature, oxygenation, hydration, and protein-calorie intake that started preoperatively must be continued. Prolonged respiratory support and antibiotic use may be necessary. Enteral feeding should be reintroduced after the 7th postoperative day once the anastomosis has healed. Healing should be confirmed by contrast esophagography. Reintroduction of feeding should be cautious due to the risk of vocal cord paralysis and dysphagia.¹³

Complications

The most common complications in the postoperative period include injury to the recurrent laryngeal nerve, prolonged tracheal intubation, unilateral or bilateral vocal cord paralysis, anastomotic fistulas, tracheal obstruction, pneumothorax, gastroesophageal reflux, esophageal stenosis, and recurrence of the fistula.^4,14

Some of these complications can be permanent, underscoring the importance of a multidisciplinary approach, regular examinations, and long-term follow-up after TEF correction surgery.6 Parents should be routinely informed about different surgical options, such as open and thoracoscopic repair, and the risks associated with each of them during preoperative counselling.^4,12

Long-term follow-up care and potential complications

Several factors determine the survival of these patients, including birth weight, associated malformations, and respiratory complications.¹³ Gastrointestinal alterations (gastroesophageal reflux disease, peptic esophagitis, gastric metaplasia, Barrett's esophagus, eosinophilic esophagitis, anastomotic strictures, eating disorders, dysphagia, and esophageal dysmotility), respiratory issues (abnormalities in lung function, asthma, aspiration, recurrent lung infections, and bronchiectasis), otolaryngological and nutritional (malnutrition and undernutrition) problems. Concerns in adults also encompass esophageal adenocarcinoma, squamous cell carcinoma, and epidermoid carcinoma.^2,15

Psychological and social impact

The psychological and social impact, as well as the reduced quality of life caused by the malformation, surgeries, and post-operative complications, persist into adulthood. Parents often experience increased anxiety and stress, especially during the diagnosis and surgery phases, concerning their child's long-term health. Children, in turn, may face challenges in social situations due to their unique eating and breathing patterns, potentially leading to social isolation and difficulties in forming friendships. Therefore, these families need psychological support and counselling, as well as participation in support groups, which can provide a platform for sharing experiences, offering emotional relief, and providing strategies to cope with the situation.^2,15

New perspectives

Currently, although open or thoracoscopic surgery for TEFs has seen significant advancements in recent years, recurrent TEFs continue to pose a therapeutic challenge, with reports of recurrence in up to 20% of cases. Therefore, endoscopic interventional therapies using the technique of de-epithelialization and sealing have been employed for TEF treatment. Endoscopic de-epithelialization is technically easier to perform and should preferably be used in the pediatric population due to being less hazardous and helping to avoid the risk of injuring other important structures. Although they have a success rate of 60% and, in many cases, require more than one approach, these minimally invasive techniques appear to be safe for TEF treatment.¹⁴

Conclusion

TEF is defined as communication between the trachea and the oesophagus and predominantly occurs in congenital cases. Diagnosing TEF, especially in its isolated form, is challenging and requires a high index of suspicion. The management involves a multidisciplinary approach and surgical correction, either through traditional or minimally invasive approaches, both with potential complications. Endoscopic interventional therapies seem to be an alternative for the correction of TEF. TEF also creates significant psychological and social challenges, persisting into adulthood. Families and patients require ongoing psychological support and participation in support groups to navigate the unique challenges posed by this condition.