ESOPHAGEAL ATRESIA TRACHEOESOPHAGEAL FISTULA

Esophageal Atresia a/o Tracheo-esophageal fistula
1. Embryology : The trachea and esophagus initially begin as a ventral diverticulum of the foregut during the third intrauterine week of life. A proliferation of endodermal cells appears on the lateral aspect of this growing diverticulum. These cell masses will divide the foregut into trachea and esophageal tubes. Whether interruption of this normal event leads to tracheo-esophageal anomalies, or during tracheal growth atresia of the esophagus results because of fistulous fixation of the esophagus to the trachea remnant to be proven.

2. Classification :
EA with distal TEF (87% )- the most common anomaly, the NG tube coiled at T4-5 level and gas will
be seen in the KUB.
EA without TEF (8%) - pure esophageal atresia, NG coiled at T4-5 level with airless
abdomen.
TEF without atresia (4%) - pure tracheo-esophageal fistula.
EA with proximal TEF (<1%).
EA with proximal and distal TEF (<1%)

Congenital isolated tracheo-esophageal fistula (TEF) occurs as 4-6% of the disorders of the esophagus
bringing problems during early diagnosis and management. More than H-type is N-type, due to the obliquity of the fistula from trachea (carina or main bronchi) to esophageal side (see the figure) anatomically at the level of the neck root (C7-T1). Pressure changes between both structure can cause entrance of air into the esophagus, or esophageal content into the trachea. Thus, the clinical manifestation that we must be aware for early diagnosis are: cyanosis, coughing and choking with feedings, recurrent chest infections, persistent gastrointestinal distension with air, and hypersalivation. Diagnosis is confirmed with a well-done esophagogram, or video-esophagogram (high success rates, establish level of the TEF). Barium in the trachea could be caused by aspiration during the procedure.

Upon radiologic doubt bronchoscopy should be the next diagnostic step. Any delay in surgery is generally due to delay in diagnosis rather than delay in presentation. Management consists of surgical closure of the TEF through a right cervical approach. Hint: a small guide-wire threaded through the fistula during bronchoscopy may be of some help. Working in the tracheo-esophageal groove can cause injury to the recurrent laryngeal nerve with vocal cord paralysis. Recurrence after closure is rare.

3. Diagnostic characteristics: The incidence is one in every 2500 live births. We see between 8-10 per year at the University Pediatric Hospital. The mother might show polyhydramnios since the fetus is unable to swallow amniotic fluid. (May be responsible for early delivery). Polyhydramnios is most commonly seen in pure esophageal atresia type. Choking, coughing and regurgitation with first feed. Excessive salivation, cyanosis with feedings. Inability to pass feeding tube into the stomach. Contrast studies (UGIS, esophagogram) are rarely needed, and of potential disaster (aspiration of contrast material). Abdominal films should be obtained to rule out the occurrence of associated gastrointestinal anomalies. Isolated TEF is more difficult to diagnose and may require repeated lateral esophagograms, bronchoscopy and esophagoscopy.

4. Management : Correct dehydration, acid-base disturbances, respiratory distress and decompress proximal esophageal pouch (Replogle tube). Evaluate for associated conditions such as VACTERL association (3 or more):
-Vertebral anomalies i.e. hemivertebrae, spina bifida
-Anal malformations i.e. imperforate anus
-Cardiac malformations i.e. VSD, ASD, Tetralogy Fallot
-Tracheo-Esophageal fistula (must be one of the associated conditions)
-Renal deformities i.e. absent kidney, hypospadia, etc.
-Limb dysplasia

Early surgical repair (transpleural or extrapleural) for those babies with no evidence of pneumonia,
adequate weight (>1200 gm) and no significant associated anomalies. Babies with Chest-X-Ray positive
findings, but adequate ABG's can also be primarily repaired. Delayed repair (gastrostomy first) for all other patients. Surgical repair consist of a 4th intercostal space right muscle-sparing thoracotomy (side of thoracotomy is contralateral to side of aortic arch of patient), closure of tracheo-esophageal fistula and primary esophago-esophagostomy. Esophagogram is done 7-10 days after repair.

Complications after surgery are: Anastomotic leak, anastomotic stricture, gastroesophageal reflux,
tracheomalacia, and recurrent TEF. The three most common anastomotic complications are in order of
frequency: stricture, leakage and recurrent TEF. Recurrent TEF after surgical repair for esophageal atresia occurs in approximately 3-15% of cases. Tension on the anastomoses followed by leakage may lead to local inflammation with breakage of both suture lines enhancing the chance of recurrent TEF. Once established, the fistula allows saliva and food into the trachea, hence clinical suspicion of this diagnosis arises with recurrent respiratory symptoms associated with feedings after repair of esophageal atresia. Diagnosis is confirmed with cineradiography of the esophagus or bronchoscopy. A second thoracotomy is very hazardous, but has proved to be the most effective method to close the recurrent TEF. Either a pleural or pericardial flap will effectively isolate the suture line. Pericardial flap is easier to mobilize, provides sufficient tissue to use and serves as template for ingrowth of new mucosa should leakage occur. Other alternatives are endoscopic diathermy obliteration, laser coagulation, or fibrin glue deposition.

Esophageal stenosis in children can be of congenital (5%) or most commonly acquired nature (95%).
Acquired stenosis is the result of repaired esophageal atresia, caustic injury, penetrating injury or reflux
esophagitis. Congenital esophageal stenosis (CES) can be the result of a membranous diaphragm, segmental hypertrophy of the muscularis and submucosal layer (submucosal fibrosis), or presence of ectopic tracheobronchial rest. CES most commonly affect the middle and distal third of the esophagus and rarely cause symptoms in the neonatal period. Symptoms can be vomiting of undigested food, regurgitation, food impaction, difficulty swallowing solid and failure to thrive. CES affecting the upper third of the esophagus is very rare and usually produce respiratory symptoms such as stridor and repeated respiratory infections. Esophageal atresia is associated with one-third of cases of CES. To establish a diagnosis investigation has to include esophagogram (relatively long, smooth circumferential narrowing), esophagoscopy with biopsy, pH monitoring and in selected cases manometry. Recognition of the correct etiologic factor that caused the stricture will pave the way for adequate management. CES is managed with forceful dilatation or hydrostatic balloon dilatation, while resection with anastomosis will be needed for intractable (fibromuscular hypertrophy) cases and those harboring tracheobronchial rests. Most intractable cases are due to the presence of tracheobronchial rest.