In terms of genetic disorders, EA is also associated with trisomies 18 and 21, as well as the chromosomal deletions 22q11 and 17q22q23.3.
The pathophysiologies of both EA and TEF are intimately related and are due to malformation of the foregut. The etiology is incompletely understood and is most certainly multifactorial. In experimental models the Sonic hedgehog gene, and other genes involved in related signaling pathways, has been implicated .
Embryologically, the primitive foregut is derived from the endoderm and forms around 4–6 weeks gestational age. The respiratory diverticulum forms from the cranial foregut and will later give rise to two lung buds. The ventral tubular structure will give rise to the trachea and the dorsal structure the esophagus. It is postulated that either the respiratory system grows away from the foregut, forming a separate structure, or that the structures grow in parallel with a caudocranial separation forming and ultimately dividing the two. As the cranial foregut is developing, the stomach develops from the caudal foregut. While the esophagus elongates in the caudal direction, its lumen decreases in size until it is almost obliterated . Normally, the lumen will reform following fusion of the esophagus and stomach. When the esophagus does not appropriately elongate (and/or the respiratory bud does not properly elongate), EA and/or TEF develop .
When diagnosed prenatally, EA is typically discovered via ultrasound. Magnetic resonance imaging may also be used, particularly when there is a high suspicion for abnormality . Suggestive sonographic findings include microgastria or absent gastric bubble, upper pouch sign (dilated proximal esophageal pouch), and polyhydramnios . Pure EA is associated with polyhydramnios in approximately 87 % of cases, but EA with distal TEF only has polyhydramnios in 50 % of cases . Despite the increasing use and accuracy of antenatal ultrasound, EA is diagnosed prenatally in 20–34 % of cases . Postnatal signs and symptoms of esophageal atresia include inability to swallow, feeding intolerance, and respiratory distress.
A thorough physical exam should be performed, particularly given the fact that EA is associated with other congenital anomalies in 48–55 % of cases , the most common of which is the VACTERL association . Common symptoms of esophageal atresia are coughing and choking, particularly when feeding. Signs of EA include inability to pass orogastric or nasogastric tubes as well as difficulty swallowing.
Laboratory examination is not required in the diagnosis of esophageal atresia. However, blood work including complete blood count, comprehensive metabolic panel, coagulation profile, and blood type with crossmatching should be obtained preoperatively, as well as to potentially screen for other congenital abnormalities. Metabolic derangements may need to be corrected prior to surgery.
Plain film radiography is often diagnostic of esophageal atresia as well as tracheoesophageal fistula. Common radiographic findings of pure EA include air in the proximal esophageal pouch without distal bowel gas and coiling of the nasal or orogastric tube in the proximal esophageal pouch. If a coincident TEF is present, there may be gas present in the stomach and distal bowel, although this may not be apparent on the initial X-ray. Patients who are unable to undergo immediate primary anastomosis will require gastrostomy tube placement for feeding purposes. In these patients, a “gap-o-gram” or gap study can be performed for operative planning and further characterization of the atresia, including measurement of the length between the esophageal ends (Fig. 20.1). A passive gap study is performed by injecting contrast into the proximal esophageal pouch (typically via nasoesophageal tube) and into the stomach and/or distal esophageal pouch via the gastrostomy tube . Alternatively, an active, or dynamic, gap study is performed using fluoroscopy while applying controlled tension with radiopaque instruments placed in both esophageal ends, in order to stretch the two esophageal ends closer together . This study is more predictive of the true gap that will be encountered intraoperatively after esophageal mobilization but carries the risk of pushing up the fundus instead of the distal esophagus, giving a false-positive impression of the length of the distal esophagus or hollow viscus perforation.
The gap-o-gram provides an accurate representation of the distance between the proximal and distal esophageal portions. Radiopaque objects, and/or contrast, are placed in both ends of the esophagus. Ideally, tension is applied to lessen the distance between the ends (as will ultimately be done in surgery when approximating the ends of the esophagus). From Pediatric Thoracic Surgery, Esophageal Replacement, 2009, pp. 321–333, Pattillo JC. With permission of Springer.
Due to the strong association between EA and cardiac defects, a transthoracic echocardiogram should be routinely performed on patients who are diagnosed with EA. Approximately 1.8–5 % of patients with EA/TEF have a right-sided aortic arch, which may impact surgical approach to repair of the EA [16, 26, 27].
All patients with esophageal atresia require repair. However, as discussed earlier, correction with native esophagus should be attempted first. In patients with a history of esophageal atresia and primary repair, indications for esophageal substitution relate to complications with the native esophagus, such as leaks, strictures, refractory gastroesophageal reflux, and recurrent tracheoesophageal fistula that precludes the use of the native esophagus .
Additional indications for pediatric esophageal replacement include caustic ingestion and peptic stricture. Although the overall incidence of caustic ingestion has continued to decline, there remain regional demographics where there are a substantial number of caustic ingestions, usually related to lye (sodium hydroxide) ingestion. This declining trend has been largely attributed to the usage of child-resistant lids on caustic products.
Tracheoesophageal fistula is often coincident with EA and must be definitively diagnosed or ruled out prior to planned repair of EA. In those patients with multiple defects, there must be strong coordination of consulting services, including anesthesiology, cardiology, neonatology, and other relevant services, to determine the proper order of surgical interventions.
In patients with suspected or confirmed EA, a Replogle suction catheter should be placed in the proximal esophageal pouch to prevent aspiration of oral secretions. Additionally, patients with EA who are not able to undergo immediate repair will require gastrostomy tube placement.
There is debate as to whether patients awaiting delayed primary anastomosis should have a cervical esophagostomy (commonly known as a cervicostomy or “spit fistula”) placed as opposed to long-term esophageal pouch suction. It is our opinion that suction alone should be implemented to keep all options open. Placement of cervical esophagostomy risks damaging the recurrent laryngeal nerve. Furthermore, the cervicostomy effectively increases the length of the gap between the esophagus and stomach . Thus, if a patient receives a cervical esophagostomy and later requires esophageal replacement, jejunal interposition can be made technically much more challenging, potentially requiring microvascular anastomosis , or impossible. While it has been advocated that cervical esophagostomy allows for patient discharge from the hospital, it has been demonstrated that patients may safely stay at home with proximal pouch suction .
The posterior mediastinum is the location of the native esophagus and is the shortest distance between the neck and abdomen for an esophageal replacement. Furthermore, this location minimizes lung compression by the conduit. This is the preferred location for the conduit.
In the past the retrosternal position has been described for various conduits [32, 33]. It may be technically less challenging than posterior mediastinal placement and was said to avoid tedious dissection in patients who have had caustic ingestions, peptic esophageal strictures, or prior cardiothoracic surgeries. Thoracotomies at that time were still high-risk procedures.
The retrohilar, or transpleural, approach is also considered technically less challenging than posterior mediastinal placement. This method is primarily of historical significance. It requires a thoracotomy to be performed and will inevitably lead to some lung compression.
Important considerations when deciding the ideal conduit route include maintenance of some anatomic normalcy, patient anatomic variations (e.g. dextrocardia, right-sided aortic arch), prior thoracic surgeries or other inflammatory processes in the chest (e.g. caustic ingestion), technical difficulty, lung compression, and prevention/reduction of gastroesophageal reflux.
Consideration should be given to remaining extrapleural during the thoracic portions of the surgery. This may be exceedingly difficult in the youngest of patients, however.
Due to surgery being performed in both the abdomen and thorax or neck, multiple positions may be required during the operation. Generally, the supine position is used for both open abdominal and laparoscopic surgery. For thoracoscopy, the patient is placed in the left lateral decubitus semi-prone position. For thoracotomy, the left lateral decubitus position is used (Figs. 20.2 and 20.3).
Demonstration of patient positioning and surgeon location for thoracoscopic repair of long-gap esophageal atresia. Note that the patient is placed in a 45° left lateral decubitus position (semi-prone).
Trocar placement for thoracoscopic repair of long-gap esophageal atresia. The thoracoscope (#1) is inserted approximately 1-centimeter inferior and anterior to the tip of the scapula, and working instruments are placed in positions #2 and #3.
In neonatal thoracoscopy, 3-mm instruments are used. In older children, 5-mm instruments are longer and may allow for better access to structures in the relatively larger thoracic cavity. The existence of a 3-mm laparoscopic vessel sealer and 5-mm laparoscopic stapler has proven invaluable.
This chapter is intended for those rare circumstances in which the native esophagus alone is insufficient to correct the problem, and delayed primary anastomosis after 3 months or the traction technique is not possible. Please refer to other chapters in this text that discuss surgical correction of esophageal atresia using the native esophagus. It is the opinion of the authors that jejunal interposition should be the esophageal substitution operation of choice, followed by gastric transposition or gastric tube interposition. The last resort would be colonic interposition.
Small Bowel Interposition (Fig. 20.4)
Jejunal transposition is shown. (a) Suitable portion of small bowel is chosen. (b) While the vasculature is preserved, a portion of small bowel is removed to provide additional length. (c) The segment of small bowel is passed into the chest in an anteperistaltic fashion. Small bowel continuity is restored. From Pediatric Thoracic Surgery, Esophageal Replacement, 2009, pp. 321–333, Pattillo JC. With permission of Springer.
Jejunum, and rarely ileum, has many distinct advantages and nowadays is the esophageal replacement conduit of choice for most. The jejunum is similar in size to the native esophagus and occupies less space in the chest than the much larger stomach. This helps to minimize restrictions on the pulmonary system. Unlike other substitution choices, the small bowel retains peristaltic activity, thus avoiding many of the late complications seen with the stomach and colon, such as stasis and reflux . Jejunal interposition is considered the most technically difficult operation of the esophageal replacement choices, and the blood supply tends to be more tenuous. It also involves three anastomoses. The ability to perform the surgery may be limited by prior surgeries, such as cervical esophagostomy, or congenital anomalies, such as intestinal malrotation.
Jejunal interposition may be used to replace the length of the esophagus or to bridge a smaller, subtotal portion of the esophagus. The use of “free” segments of small bowel, requiring a microvascular anastomosis, has been described in the pediatric literature [34, 35] but is much more commonly seen in adult populations, due to the difficulty of performing such an anastomosis in a pediatric patient. A pedicled graft is much more commonly used .
Jejunal interposition is performed as a single-stage operation and can be performed as early as 1 month of age [29, 36].
Following induction of anesthesia, prepping, and draping, if applicable, the cervical esophagostomy is taken down. Next, right thoracoscopy is performed, with the patient in the left lateral prone position, to determine if small bowel interposition will be feasible and the length of small bowel which will be required is sufficient. If small bowel interposition is to be performed, a right posterolateral thoracotomy is performed, and the distal esophagus is dissected to allow easy passage of the jejunum into the thorax. The proximal esophagus is maximally prepared to facilitate the proximal anastomosis. The skin is reapproximated, and the patient is placed into the supine position.
The second step is to perform a midline laparotomy. It is the opinion of the authors that mobilizing the jejunal segment laparoscopically would carry an excessively high risk of compromising the vascular supply to the bowel. The gastrostomy tube is removed and the gastrostomy is closed.
The superior portion of the neoesophagus will be a point just distal to the first feeding artery from the ligament of Treitz. The jejunum is transected distal to the ligament of Treitz and at the level of the third major mesenteric branch to the bowel. The “excess” jejunum is discarded and small bowel continuity restored. The first two mesenteric branches are ligated, with care taken to leave the peripheral arcades intact.
The phrenoesophageal ligament is divided, and the gastroesophageal junction and proximal stomach are mobilized. The jejunal segment is introduced into the retrohilar portion of the chest, in a retrocolic, retrogastric fashion via the esophageal hiatus with stay sutures.
The patient is placed in the right lateral decubitus position, and the thoracotomy incision is reopened. The jejunum is anastomosed with the proximal and distal esophagus in an interrupted fashion using braided, absorbable suture. Nasogastric tube is placed, as well as a chest tube, prior to closure of the chest and abdomen. A gastrostomy or jejunojejunostomy can be performed for feeding.
Gastric Transposition (Also Referred to as Gastric Pull-Through or Pull-Up) (Fig. 20.5)
Gastric transposition for esophageal replacement. (a) Stomach is mobilized laparoscopically. (b) The stomach is pulled into the right hemithorax and the distal esophageal stump removed. (c) The cervical esophagus is anastomosed to the gastric fundus, and laparoscopic pyloroplasty is performed.
Not all patients will be suitable candidates for small bowel interposition. Intestinal malrotation has an increased incidence in patients with EA, and these patients may have vascular anatomy that is prohibitive to performing small bowel interposition. These patients are better served with a gastric conduit for esophageal replacement [23–25]. Advantages of gastric transposition include robust blood supply, the relative ease of bringing the stomach into the chest, and the presence of only one anastomosis. Of note, gastric transposition is the only esophageal replacement surgery that is able to be performed in its entirety in a minimally invasive fashion. Disadvantages involve the large size of the stomach, lack of peristalsis, and gastric reflux . Patients who have had cervical esophagostomy will require takedown of the stoma and a subsequent cervical anastomosis, which will require an open approach. Discussion of this technique has been described by multiple authors [38–40] and will not be discussed herein.
Following induction of anesthesia, placement of the patient in the supine position, prepping, and draping of the patient, laparoscopic entry into the abdomen is obtained in a fashion similar to that used for a Nissen fundoplication.
The G-tube is removed and the gastrostomy is closed. The abdominal wall defect previously containing the G-tube is used as an additional laparoscopic port site. The stomach is completely mobilized, including division of the gastrocolic and gastrohepatic ligaments. Traction sutures are placed in the distal esophageal stump after it too has been mobilized. The left gastric and gastroepiploic arteries are ligated along with the short gastric vessels. Care is taken to preserve the right gastric and gastroepiploic arteries. The esophageal hiatus is dilated, and the stomach, with attached distal esophagus, is passed into the right hemithorax.
The patient is placed in the 45-degree left lateral decubitus position, and the right hemithorax is entered thoracoscopically, in the fashion traditionally used for EA repair. With the use of traction sutures, the stomach is brought into the posterior mediastinum. The distal esophagus is resected from the stomach, and esophagogastrostomy is performed with a single layer of absorbable suture (typically 4–0 or 5–0). A 360-degree gastric fundoplication around the anastomosis may be performed .
The patient is returned to the supine position, and attention is returned to the abdomen. The gastric antrum is fixed to the crura with nonabsorbable suture, and a Heineke-Mikulicz pyloroplasty may be performed, although there is no consensus as to the advantage of a pyloroplasty. Feeding tube jejunostomy may be performed prior to closure of the abdomen.
Gastric Tube Interposition (or Gastric Tube Esophagoplasty) (Fig. 20.6)
Reversed gastric tube. The greater curvature of the stomach is used to form the reversed gastric tube for esophageal replacement. From Pediatric Thoracic Surgery, Esophageal Replacement, 2009, pp. 321–333, Pattillo JC. With permission of Springer.
There are have been numerous reports on various types of gastric tube conduits for the use in esophageal atresia [42–45], but none have been performed in children in a minimally invasive fashion, as many date from a time prior to the era of minimally invasive surgery. An open technique favored by the authors, reversed gastric tube (RGT), is presented.
Advantages of the gastric tube interposition include avoidance of exposure of a small bowel or colonic conduit to refluxed gastric secretions, a single anastomosis (which is typically intrathoracic), and a smaller volume conduit when compared with gastric transposition. It should be noted that in a patient in whom the G-tube is very close to the greater gastric curvature, RGT may not be possible. The RGT has the disadvantage of being antiperistaltic, but isoperistaltic gastric tubes have been described [42, 44–46].