Diagnosis and management of congenital type D esophageal atresia

Esophageal atresia (EA) is a congenital disease in which the middle esophagus is missing, and it is often associated with one or more tracheoesophageal fistulas (TEFs), The reported incidence is from 1 in 2500 births to 1 in 4500 births [1‐4]. Gross classification of the anatomic patterns of EA is often used. Type D EA is defined as EA with a double (proximal and distal) fistula. Though rare, this form is found more often than originally thought. The incidence of type D EA is about 1%. Because of its low incidence rate and lack of specific clinical manifestations, type D EA is often misdiagnosed as type C EA, leading to an unplanned reoperation. How to reduce the misdiagnosis rate and improve the operative success rate are important problems for pediatric surgeons. Following approval by the Capital Institute of Pediatrics and Beijing Children’s Hospital Review Board, we reviewed 10 patients who were diagnosed with type D EA and underwent EA/TEF repair in the Capital Institute of Pediatrics and Beijing Children’s Hospital from January 2017 to May 2022. We also herein discuss the diagnostic and treatment strategies for type D EA.

The clinical characteristics of the patients in the neonatal and non-neonatal groups are shown in Tables 1 and 2, respectively. In all patients, esophagography with water soluble contrast material was performed in the neonatal period, and a proximal TEF was found in only one patient.

Congenital EA is a serious digestive tract malformation caused by an esophageal development disorder at 3 to 6 weeks of embryonic development. It is often accompanied by one or more TEFs because of incomplete separation between the esophagus and trachea. Type C EA is the most common, accounting for about 85% to 90% of all cases. Type D EA is characterized by both a distal and proximal TEF and accounts for only 1% of all cases of EA. A few case reports of type D EA are present in the literature [5‐7].

The main clinical signs of type D EA after birth are spitting, choking, and inability to pass a feeding or suction catheter through the mouth or nose into the stomach. Because these signs are not different from those of type C EA, it is difficult to distinguish between the types by clinical signs alone.

Esophagography is a routine examination technique for EA. Water soluble contrast material such as iohexol should be used to avoid or reduce the damage caused by inhaling the contrast agent. Contrast agent (1–2 mL) should be slowly injected into the gastric tube. The portion of the gastric tube with the lateral hole must be cut off and advanced into the esophagus for about 10 cm. Esophagography is performed with the patient in different positions to understand the length and width of the upper esophageal pouch and the potential presence of a TEF. It has been suggested that the prone position can be used for esophagography and that the fistula can be more easily displayed in this position [8]. After examination, the contrast agent in the upper pouch should be pumped as soon as possible. The position of the distal TEF shows few changes, so the length of the missing esophagus can be predicted according to the position of the upper esophageal pouch. It is difficult to identify the proximal TEF by esophagography. In the present study, all 10 patients underwent esophagography, but the proximal TEF was found in the neonatal period in only one patient. One newborn was considered to possibly have type D EA because the esophagogram showed that the proximal pouch was thin (0.9 cm in diameter). Our clinical experience has shown that the proximal pouch diameter is about 1.3 cm in type C EA. In the above-mentioned patient, type D EA was finally confirmed by bronchoscopy. Therefore, the possibility of having a proximal fistula should be considered when esophagography shows a thin proximal pouch.

Bronchoscopy has obvious advantages over other examination methods for the diagnosis of TEF [9, 10]. Eight (80%) children in the present study were definitively diagnosed by bronchoscopy. At the same time, the distance can be measured between the fistula and the glottis, which can provide a basis for the operative approach through the chest or neck. However, because of the low incidence of type D EA, there are still many disputes regarding whether every child with congenital EA requires bronchoscopy. We suggest the use of bronchoscopy when the esophagogram shows a thin proximal pouch and when the child has recurrent pneumonia and no weight gain after operative treatment of type C EA [11, 12]. Repeated bronchoscopy can be performed when the diagnosis is unclear. To improve the recognition rate of the fistula, we injected methylene blue into the esophagus through the gastric tube and observed whether the trachea was stained blue during tracheoscopy [13].

Whether to repair the proximal fistula in type D EA through the chest or neck has been a topic of debate. Parolini et al. [14] systematically evaluated 90 cases of TEF in 17 articles and concluded that the neck approach could be used for fistulas above the T2 level and that transthoracic surgery could be used for fistulas at the T2 to T4 level. Another study indicated that fistulas at the T2 to T3 level could be repaired through the neck and that fewer complications and a lower recurrence rate occurred after neck surgery [15]. The diagnostic rate by esophagography in the present study was low, and the fistula positioning mainly depended on bronchoscopy to measure the distance from the fistula to the tracheal lung protrusion and from the fistula to the glottis. The correlation between this distance and the thoracic vertebra requires further examination. The present study suggests that the fistula near the tracheal bulge can be repaired by transthoracic surgery and that the fistula closer to the glottis can be repaired through the neck. An operation through the neck is easier than transthoracic surgery. The overall treatment was satisfactory, and no recurrence after proximal fistula repair occurred in this study.

During surgical repair of type D EA, we observed that the proximal TEF was short and thin, and all were located in the proximal esophageal lateral wall but not at the end of the esophagus, as described in traditional textbooks. This finding explains the low positive rate of esophagography and provides an anatomical basis for intraoperative identification of fistulas. The surgical method also varied based on the different morphology of the proximal and distal fistulas. The distal TEF is located at the end of the esophagus, and it is thick and easy to discern. It can be directly cut off after closure by titanium endoclips [16]. The proximal TEF is short and thin. It is recommended to preserve as many tissues as possible on the tracheal side to facilitate repair.

Type D EA lacks specific clinical manifestations. Misdiagnosis as type C EA is the main cause of an unplanned reoperation. Tracheoscopy is an important examination method for confirmation of type D EA. Patients without severe malformations have a good prognosis.