Introduction

Esophageal atresia (EA) and tracheoesophageal fistula (TEF) are relatively common congenital anomalies with an incidence of 1/3,000-4,000 live births. The embryologic events leading to this malformation are poorly understood, and while the incidence is slightly increased in twins, there is no strong support for an inheritable mechanism. The pathogenesis is likely multifactorial. Chromosomal anomalies have been reported in up to 10% of cases, but no specific chromosomal defect has been confirmed. Antenatal detection is challenging, it may be suspected with third trimester ultrasound demonstrating polyhydramnios with or without a stomach bubble. Antenatal detection rates range from 10-42% of cases. Prenatal detection does not appear to affect outcome or prognosis. Common findings on presentation include excessive salivation, respiratory distress, and cyanosis due to aspiration. Abdominal distention may occur due to inspired air passing through the fistula into the stomach. Associated congenital anomalies are common, with cardiac anomalies noted in almost 40% of cases. Up to 65% of affected patients have additional congenital anomalies.
There are five major anatomic variants of EA.
Type Prevalence Variation
A 13% Atresia without a fistula
B 1% Proximal atresia, with fistula from proximal esophagus
C 78% Proximal atresia with distal fistula
D 2% Proximal atresia with double fistula
E 13% H-type TEF with absence of atresia

Diagnosis and Evaluation

Diagnosis of EA/TEF is confirmed by passing an OG tube into the stomach. The tube will typically stop around 12cm. A chest radiograph will show the tube either coiled in the upper esophageal pouch or coming to an abrupt end. Differential diagnosis at this time includes esophageal perforation. Absence of air in the GI tract would raise concern for a type A or B variant fistula. Contrast studies are not necessary to make the diagnosis and may lead to complications of aspiration of radiographic contrast in the tracheobronchial tree, and it can lead to serious morbidity. Further elucidation of the tracheal and esophageal anatomic defects is typically deferred until the time of surgical repair.
Due to association with VACTERL and other anomalies in as many as 70% of these patients, preoperative evaluation should include careful physical examination and testing to include echocardiography, renal ultrasonography, and chromosomal analysis. Other preoperative measures include type and cross match of blood, antibiotic prophylaxis, and administration of Vitamin K. Preoperative echocardiography for the diagnosis of congenital heart disease and evaluation of the aortic arch will guide the timing of repair, intraoperative anesthetic management, and the sidedness of surgical chest exploration. Classically EA/TEFs are repaired from a right approach. However, the incidence of concomitant right aortic arch (RAA) is estimated from 5-13%, and its presence may lead to a preferential approach from the left side. Primary repair can be achieved in patients with a RAA through a right-sided approach, but this is surgeon dependent.

There have been multiple criteria schemes utilized to determine operative timing and prognosis; these include the Waterston, Montreal, Bremen, and Spitz classification systems. Ultimately timing must be individualized for each patient. Infants that are stable from a cardiac and respiratory standpoint should undergo expeditious chest exploration and repair. Anomalies that are not life-threatening in patients with physiologic derangements should be optimized prior to intervention.

Operative Management

The anesthesiology team should have routine monitoring in place to include an arterial catheter, electrocardiogram monitor, pulse oximeter, and a thermal probe. An awake intubation is commonly performed to allow spontaneous breathing. The goal of airway management is to provide adequate ventilation to the lungs while minimizing ventilation down the fistula. Fistula ventilation occurs intraoperatively, it can lead to ineffective pulmonary ventilation, gastric distention or rupture, hypotension, or reflux of gastric contents. Careful positioning of the ETT with a posterior facing bevel above or occluding the TEF, selective left mainstem bronchial intubation, catheter occlusion of the TEF, and percutaneous decompression of the stomach are all options for management. Some surgeons routinely perform endoscopy of the proximal pouch and bronchoscopy to identify the presence of fistulas and ascertain the location of the ETT. A 10 French Replogle is placed in the proximal esophageal pouch. The patient should be in the near prone position with the right side elevated 30 degrees. This provides access to the area between the anterior and posterior axillary line for trocar placement or thoracotomy, and gravity helps retract the lung.
Typically thoracoscopic repair requires 3-4 ports. The chest can be entered with a Veress needle in the 5th intercostal space between the mid and posterior axillary line. Insufflation of the pleural cavity to a pressure of 4 to 6 mm Hg at a flow of 1 L/min of CO2 significantly improves visibility of the mediastinum by compressing the lung. Initial survey of the pleural cavity is performed, once the azygos vein is identified, the relative position of the fistula can be determined. This vein is often the marker for the site of the TEF as it enters the trachea. A branch of the vagus nerve frequently passes over the area as well. At least 2, if not 3 additional ports will be placed, depending on the need to further retract the lung. The superior port needs to be 5-mm to introduce an energy device, surgical clips, or suturing of the anastomosis, though the others may be 3mm. The azygous vein is ligated and divided, and the TEF is dissected circumferentially near the trachea, with care to preserve small vessels to the midesophagus arising directly from the aorta. A vessel loop is placed around the TEF to provide traction, and a fine, absorbable suture is placed at the end of the TEF on the esophageal side. The TEF is divided, using either clips or suture ligature, and the tracheotomy is oversewn. The tracheal anastomosis is tested under saline with slight hyperinflation from the anesthesia team. The azygous vein or mediastinal pleura can be used to cover the tracheal suture line to reduce the risk of a recurrent TEF. Additional coverage options include intercostal muscle flaps, pericardium, or autologous tissue products.
Proximal pouch identification is facilitated with gentle pressure applied to the oral tube by anesthesia. A traction suture is place to aid dissection of the proximal pouch. The proximal atretic esophagus is mobilized up to the level of the thoracic inlet and into the neck to acquire adequate length to achieve primary repair without tension. This is performed with gentle blunt dissection and care not to injure or enter the trachea. Extensive dissection around the open distal esophagus should be avoided to reduce the risk of ischemia to the midesophagus. Once adequate mobilization is achieved, a tension-free primary anastomosis can be performed. The proximal pouch is opened at its most dependent portion. A posterolateral row of interrupted sutures is placed. The OG/NG is passed under direct visualization into the lower esophagus and into the stomach. The anterior wall is completed in a similar fashion. A small catheter may be placed just proximal to the anastomosis and a small amount of saline is used to test for a leak. If adequate length is not present, a circular myotomy can lengthen the proximal esophagus approximately 1.0cm. A single chest tube is placed through the inferior trocar site with the tip near the anastomosis.

Postoperative care

Postoperative extubation is preferred to avoid positive pressure on the tracheal repair, but extubation is patient and institution dependent. Tube feeds are typically started slowly; some surgeons provide parenteral nutrition until tube feeds can be provided at goal. A contrast swallow can be performed at 1 week to assess for leak and caliber of the anastomosis. Anastomotic leak occurs 10-15% of the time, and it may be early or late. Early leak is diagnosed by drain output, pleural effusion, pneumothorax, and sepsis.  While 95% of controlled leaks will commonly seal with time, IV antibiotics, and good nutrition, uncontrolled leaks or perstistant leaks may require anastamotic revision or diversion.  Strictures occur in 10-20% of cases, more commonly when a leak was present. This may present indolently as failure to thrive or as acute choking or gagging. Stricture can be diagnosed with esophagoscopy or a contrast swallow, and most are treated with simple dilation. Recurrent TEF may occur after an anastomotic disruption, or it may represent a missed proximal fistula. It may heal spontaneously with appropriate nutrition, but it may also require reoperation.

GERD is common after EA/TEF repair, likely due to abnormal esophageal motility. Reflux precautions and medications to minimize reflux are commonly used.  Operative intervention is necessary in nearly 50%, and often times a partial wrap is used to minimize feeding problems as a result of the intrinsic dysmotility. Tracheomalacia occurs in 8-15% requiring long-term ventilator support.  Overall survival rates of greater than 90% have been achieved in stable operative candidates. Unstable infants have an increased mortality, 40-60%, most of which is due to associated cardiac anomalies.

References

Cameron, J. et al. (2008). Current Surgical Therapy. Esophageal Atresia and
Tracheoesophageal Fistula. 9th Ed., Mosby, 2008. pp 71-75.

Fischer, J. (2012). Mastery of Surgery. Chapter 77, Surgical Repair of
Tracheoesophageal Fistula and Esophageal Atresia. 6th Ed., Lippincott, 2012. pp. 925-937.

Hackam D.J., Grikscheit T.C., Wang K.S., Newman K.D., Ford H.R. (2010). Chapter 39. Pediatric Surgery. In F.C. Brunicardi, D.K. Andersen, T.R. Billiar, D.L. Dunn, J.G. Hunter, J.B. Matthews, R.E. Pollock (Eds), Schwartz’s Principles of Surgery, 9e. Retrieved April 9, 2012 from https://www.accesssurgery.com/content.aspx?aID=5029784