Congenital anomalies of the esophagus occur in as many as 1 per 3000-5000 births, with esophageal atresia (EA) and tracheoesophageal fistula (TEF) being the most common types (and, therefore, the types that receive more emphasis). Congenital stenosis or obstruction is also encountered. Congenital muscular hypertrophy, webs, cysts, and tracheobronchial remnants are observed.  Other lesions, such as congenital esophageal stenosis, duplications, and cysts, occur less frequently.
The recorded history of EA dates back as early as 1670 when Durston described the presence of a blind-ending upper esophageal pouch in a conjoined twin; however, surgical therapy for EA was not suggested until 1869. Steele made the first attempt at surgical correction for EA in 1888. He performed a gastrostomy in a patient with pure EA, hoping to perforate what he suspected to be an esophageal membrane.
In 1913, Richter proposed fistula ligation with anastomosis of the two esophageal ends for EA with TEF. Although he considered primary repair to be the best option, he also acknowledged the impracticality of this procedure at the time. Instead, he ligated the fistula intrathoracically. His patient did not survive long enough to attempt an esophageal anastomosis.
The first patient to survive a congenital esophageal anomaly was born in 1931 with a TEF and no atresia. The fistula was repaired with a transtracheal incision in 1935, the same year that the first survivor of EA was born. The infant with EA was treated with gastrostomy feedings and a jejunal interposition. Both of these children had an isolated defect (atresia or fistula), and treatment was successful without a thoracotomy. The treatment for EA with TEF proved to be more difficult. Pneumonia, mediastinitis, poor airway control, and fluid management problems were frequent complications.
In 1936, Lanman was the first to perform a repair with an extrapleural approach. The first patient to undergo the technique survived only 3 hours. In 1938, Shaw performed the first fistula ligation and primary anastomosis of the esophagus for EA-TEF. This patient died 12 days postoperatively from a transfusion reaction.
In 1939, the first two successful treatments of patients with EA-TEF occurred independently, one day apart, by Leven and Ladd. They performed staged repairs involving gastrostomy placement followed by fistula ligation 5 weeks and 4 months later, respectively. Cervical esophagostomies, the use of jejunal interposition, and an antethoracic skin tube for esophageal reconstruction were use in the years to follow.
Haight completed the first successful primary repair in 1941. The procedure involved a left extrapleural approach, fistula ligation, and a single-layer esophageal anastomosis. Haight later switched to a right extrapleural approach and modified his technique to a two-layer telescoping anastomosis in an attempt to diminish leak risk.
By 1944, one third of the children with EA-TEF survived primary repair. Advances in preoperative preparation, antibiotic treatment, and intraoperative and postoperative management contributed to more favorable survival rates. Despite the increased success, leaks, strictures, and lower esophageal segment dysmotility were common postoperative problems.
The prognosis and treatment course for infants with esophageal atresia (EA) and/or tracheoesophageal fistula (TEF) and other congenital lesions has improved over the past 60 years. Advances in perinatal and neonatal care have been paramount in reducing the morbidity and mortality rates associated with these conditions. Currently, associated congenital anomalies and pulmonary complications contribute most significantly to adverse outcomes.
Infants with very low birth weight or serious cardiac abnormalities are at increased risk for poor outcome. Improvements in the prevention and management of these high-risk infants would improve outcome and survival rates. In addition, enhanced prenatal detection of EA and/or TEF and other congenital anomalies allows for better prenatal counseling and preparation for the delivery at a tertiary medical center.
Esophageal defects are currently repaired with thoracoscopy; robotic-assisted surgery may be used in the future. 
Tissue engineering for esophageal replacement, in utero intervention, and minimally invasive techniques such as thoracoscopy and robotic assistance may be used in years to come to further improve treatment of these infants.
The esophagus can be divided into several segments on the basis of its blood supply. The cervical portion of the esophagus is well vascularized and thought to have good intramural vascular communications. The cervical esophagus is supplied by the inferior thyroid artery and accessory vessels derived from the common carotid, subclavian, vertebral, ascending pharyngeal, superficial cervical, and costocervical arteries. Mobilization of the upper esophagus is generally well tolerated.
The thoracic portion of the esophagus has a segmental blood supply. The connections in this region are the most tenuous, and care should be taken during mobilization of this segment to reduce the risk of ischemia. The bronchial arteries provide the main vascular supply at this level, and one to three bronchial branches enter the esophagus at the level of the tracheal bifurcation. Variable branches originating directly from the aorta may also be present in this region.
The lower thoracic esophagus is supplied by three unpaired esophageal branches arising directly from the aorta. These branches may anastomose with branches from the intercostal and bronchial arteries. Branches from the internal mammary and carotid arteries may also be present here. The abdominal esophagus is supplied by the ascending branch of the left gastric artery and branches of the left inferior phrenic artery.
Before surgery, the position of the aortic arch should be confirmed, preferably by echocardiography.  The surgical approach should be performed on the side opposite of the aortic arch. A right-side aortic arch occurs in 5% of infants with EA.
Although the venous drainage of the esophagus is not described here, the azygos vein serves as a good landmark during surgery. The esophageal ends, particularly the distal segment in a TEF, are often readily visualized once the azygos vein has been divided or reflected.
The esophagus is largely innervated by the autonomic nervous system. Sympathetic innervation plays a minor role and arises from the pharyngeal plexus in the upper esophagus and the stellate ganglia in the lower cervical and upper thoracic portions. The aortic plexus, sympathetic chain, and splanchnic nerves supply the remainder of the thoracic esophagus.
In the abdominal segment, fibers from the celiac ganglion pass around the left gastric and inferior phrenic arteries to innervate the esophagus. Parasympathetic innervation to the esophagus is provided by the vagus. Parasympathetic function includes stimulation of smooth muscle and secretory activity. The vagus also aids the sphincteric function of the lower esophagus. The recurrent laryngeal nerves pass cranially in a groove between the esophagus and trachea, supplying the cervical and upper one third of the thoracic esophagus.
The vagus nerves descend caudally, arborize to form the esophageal plexus, and then coalesce into the left and right vagal trunks, which overlie the anterior and posterior lower esophagus, respectively. Because of its course along the esophagus, the vagus is another helpful landmark during operative esophageal procedures. Disruption or injury to the vagus nerves during surgical manipulation has been proposed as a mechanism of dysmotility following esophageal repair.
Esophageal atresia and tracheoesophageal fistula
EA is a condition in which the proximal and distal portions of the esophagus do not communicate. The upper segment of the esophagus is a dilated blind-ending pouch with a hypertrophied muscular wall. The pouch typically extends to the level of the second to fourth thoracic vertebra. In contrast, the distal esophageal portion is an atretic pouch with a small diameter and a thin muscular wall; it usually extends 1-2 cm above the diaphragm.
TEF is an abnormal communication between the trachea and esophagus. When associated with EA, the fistula commonly enters the trachea posteriorly just above the carina. However, isolated TEF, or an H-fistula, can occur at any level from the cricoid cartilage to the carina.
Because the esophagus is discontinuous, an infant with EA cannot swallow and appropriately handle secretions. Infants exhibit persistent drooling and aspiration or regurgitation of food after attempted feedings. Patients who have EA with distal TEF are at risk for additional complications related to the tracheoesophageal communication. When infants with this anomaly strain, cough, or cry, air enters the stomach through the fistula. As a result, the stomach and small intestine become dilated, elevating the diaphragm and making respiration more difficult.
Gastric secretions may also reflux retrograde through the fistula into the tracheobronchial tree, contributing to pneumonia and atelectasis. Abnormal esophageal motility is common in children with congenital anomalies of the esophagus.
Several different types of EA and TEF have been described. The frequencies calculated from a summary of six long-term studies are provided for each type. The most common abnormality (84%) is EA with a distal TEF. Isolated atresia with no fistula is the next most common finding (8%), followed by isolated TEF with no atresia (4%). EA with proximal and distal fistulas (3%) and EA with a proximal fistula (1%) are less common.
Esophageal stenosis, web, and muscular hypertrophy
Congenital esophageal stenosis is a narrowing of a region of the esophagus. A web, or diaphragm, consists of a thin squamous epithelial membrane in the esophageal lumen. It typically causes a partial obstruction in the middle to lower esophagus. Congenital muscular hypertrophy is characterized by submucosal proliferation of smooth muscle and fibrous connective tissue beneath a normal squamous epithelium. Individuals with congenital muscular hypertrophy may be asymptomatic. [4, 5]
Esophageal duplications, rests, and cysts
An esophageal duplication may be open at both ends (double esophagus), open at one end (diverticulum), or closed (elongated cyst). Rests are areas where embryonic tracheal or esophageal cells reside in mesodermal tissues. These areas may form cysts in the muscular tissues. A choristoma is a distinct cartilaginous cyst that partially or completely encircles a region typically in the lower third of the esophagus.
Columnar epithelium–lined lower esophagus
The congenital form of this condition is associated with gastroesophageal reflux (GER). Whether this lesion, also called Barrett esophagus, is congenital or acquired is unclear.
Laryngotracheoesophageal cleft (LTEC) is defined as a midline communication among the larynx, trachea, and esophagus.
The etiology of EA is unknown; however, many theories have been proposed.
The esophagus and trachea both are derivations of the primitive foregut. The larynx and trachea outpouch from the foregut at 22 days' gestation, and the lung buds are typically formed by day 26. Lateral mesodermal ridges form in the proximal esophagus during the fourth week of gestation, and the fusion of these grooves in the midline separates the esophagus from the trachea at approximately 26 days' gestation. The esophageal lumen forms following a process of mucosal proliferation and subsequent vacuole formation. Esophageal anomalies result from failure of these processes.
Numerous theories have been postulated concerning the embryogenesis of EA, including asymmetric growth of the esophageal mesenchyme and the epithelial lining, an increased cell proliferation rate in the trachea, a lack of tracheoesophageal separation, notochord abnormalities, delayed or absent apoptosis, and neural crest abnormalities.
Several theories have also been suggested for TEF. Failure of lateral ridge fusion or incomplete septation, abnormal epithelial connections that develop between the separated trachea and esophagus, and vascular deficiencies have been proposed to explain EA and TEF. Intestinal atresias have been experimentally produced by interrupting the blood supply to the intestine, but convincing support for this theory has not been demonstrated for EA.
The fetal heart begins beating during 4 weeks' gestation, and a vascular accident causing EA would have to occur before the sixth week of development. However, a 9-mm embryo with an established EA-TEF has been reported, indicating that the defect may occur before the vascular tree is fully developed.
Many children with EA and TEF have been reported to have an insufficient esophageal blood supply. Furthermore, several reports have shown an association between EA and a single umbilical artery or other abnormalities that may result in vascular compromise.
Aberrant vessels and an enlarged heart have also been cited as potential causative agents for tracheoesophageal malformations. These may cause excessive pressure on nearby organs, such as the esophagus and trachea. Other reports suggest that structures of the developing embryo are not rigid enough to be injured by this mechanism.
Although genetics has not been found to play a definitive role in the origination of EA-TEF, several chromosomal defects and gene associations have been suggested. Genetic involvement has also been described for conditions in which EA is one of many anomalies, such as oculodigitoesophageoduodenal (ODED) syndrome (ie, Feingold syndrome), trisomy 18, and Down syndrome.
Other etiologic factors (eg, vitamin deficiencies; drug exposures; viral, chemical, and physical external events) have been reported to cause tracheoesophageal malformations in experimental models and in humans.
Other congenital anomalies
One proposition is that esophageal webs result from a failure of esophageal vacuoles to coalesce at 25-31 days' gestation, which normally leads to complete luminal patency.
True esophageal duplications may develop from persistent esophageal vacuoles, whereas cysts result from remnants of the dorsal notochord, abnormal tracheobronchial tree branching, or primitive foregut diverticula. Cysts may be formed when groups of cells that are capable of forming a portion of esophagus, stomach, or pulmonary tree are pinched off from the developing foregut.
Congenital rings are thought to result from incomplete separation of respiratory tissue from the esophagus during fetal life.
Stenosis results from abnormal rests of respiratory tissue in the esophageal wall or fibromuscular hypertrophy.
LTECs may result from faulty growth of the foregut folds, resulting in failure of the posterior larynx to close and allowing persistence of the primitive tracheoesophageal space.
Esophageal atresia has an incidence of 1 in 3000 in the United States. Internationally, EA occurs in 1 per 3000-5000 live births. Males have a slightly increased risk for EA compared with females, and one study in California reported a higher incidence of EA in white populations (1 per 10,000 births) compared to nonwhite populations (0.55 per 10,000 births).
True congenital stenosis of the esophagus is rare. It occurs in 1 in 25,000-50,000 births. Incidence is higher in Japan.
The survival rate of patients with esophageal atresia (EA) and/or tracheoesophageal fistula (TEF) has immensely improved since Haight's first successful repair in 1941. Early diagnosis and advancements in neonatal anesthesia, surgical technique, treatment of associated anomalies, and intensive care management have improved the prognosis. Most children treated for EA have a normal lifespan. Despite an increased number of patients with severe congenital anomalies, survival rates have been reported as high as 95%. In uncomplicated cases, survival rates are virtually 100%.
Traditionally, prognosis for children with EA-TEF was based on birth weight and the presence of pneumonia and associated congenital anomalies. Because of advancements in neonatal care, birth weight does not affect survival rate unless it is severely low, and pneumonia may be treated successfully. Currently, cardiac and chromosomal abnormalities are the most significant causes of death. Infants with a birth weight less than 1500 g, major congenital cardiac abnormalities, severe associated anomalies, preoperative ventilator dependence, and/or long gap are at increased risk.
Dysphagia, frequent night coughs, dyspepsia, and recurrent respiratory infections are frequent results of the less distensible esophagus and gastroesophageal reflux. Gastroesophageal reflux occurs in as many as one half of these patients and many require antireflux operations. Feeding difficulties also are common, particularly during the first several years after repair. Choking, vomiting, and food impaction occur. These symptoms, like many following EA repair, diminish over time, and 70-80% of adolescents report no or only occasional swallowing impairment. Most patients who have undergone EA repair have abnormal peristalsis with decreased contractile activity and inefficient clearance capacities.
In one series, after an average of 8.8 years of follow-up care, all patients were reported to eat excellently or satisfactorily, with more than 90% eating no differently than their siblings. Normal respiratory function is observed in half of patients 3 months postoperatively. Tracheomalacia, vascular rings, and decreased lung volumes account for the abnormal respiratory function in the other children. Tracheomalacia occurs in 10% of patients with TEF. Most outgrow this problem; however, some children require more aggressive therapy.
Growth retardation has been observed in some children who have had EA repair, but this observation varies. Patients treated for EA-TEF are at higher risk for developing esophagitis and Barrett epithelium. Reports of esophageal carcinoma decades after EA-TEF repair are becoming more frequent as the first generation of survivors progresses through adulthood. Surveillance esophagoscopy has been proposed to provide early detection for esophageal abnormalities. 
Despite the complications, the results of EA-TEF repair have dramatically improved. Many symptoms are alleviated over time, and most children and adults enjoy normal lifestyles and have no complaints concerning their quality of life or eating habits. Even by school age, children who had many complications in infancy reported few restrictions at school or in participation in sports with little or no effect on school attendance and social activities. The outcome for these children and children treated for other congenital lesions is generally good.
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