Why are there long-term problems after EA surgery?

While EA surgery restores the continuity of the esophagus and will separate the esophagus from the trachea, the structure of both the esophagus and the trachea remain abnormal. This often leads to long-term problems.

figure_6

Separating the Trachea and Esophagus

The Esophagus

First, the area where the esophagus is sewn back together (and the areas of the esophagus above and below this point) won’t have a normal network of nerves to control the muscles in the wall of the esophagus, so the normal contractile waves that are supposed to occur in the esophagus during swallowing don’t happen. This can prevent normal swallowing. EA patients may have difficulty swallowing, get food stuck in the esophagus, and/or have food or liquids get stuck in the esophagus, pass back to the mouth, and get aspirated into the lungs.

Second, the Lower Esophageal Sphincter needs normal signals from the nerve network in the esophagus to tell it when to open and close. Without those signals, it may open randomly, allowing gastric acid and gastric contents back into the esophagus. This can cause inflammation in the esophagus, known as esophagitis or heartburn. In addition, these liquids can flow back up the esophagus into the mouth and then get aspirated into the lungs. This is called Gastroesophageal Reflux (or GERD). Gastric acid and stomach contents are very harmful to the lungs, and can lead to lung disease.

figure_7

Structure of the Trachea and Esophagus (taken from Kovesi, Chest 2004)

The Trachea

Normally, the cartilages in the trachea are C-shaped, with a short fibrous (or membranous) portion at the back. Especially around the area of the original TEF, the cartilages are more U-shaped, with a long membranous portion. In the mildest situation, in everyone who previously had a TEF, whenever they cough, this membranous portion vibrates like a clarinet reed, giving a very loud, vibratory, brassy, or “honking” cough. Pretty much everyone with a previous TEF will have this cough, for life. In more severe cases, this membranous portion, being abnormally soft, bulges into the hollow center of the trachea, particularly when pressure inside the chest is increased. This may happen during coughing, crying, eating, or defecating. This is called clinically significant Tracheomalacia. Because the trachea collapses during cough, secretions in the lungs aren’t expelled efficiently during respiratory infections, increasing the risk of bronchitis or pneumonia (a lung infection). In the most severe cases, tracheomalacia can lead to chronic wheezing (a whistling sound coming from the chest), and blue spells in babies (during the situations mentioned above).

Recent research has shown that a number of patients with EA also have a Laryngeal Cleft. A laryngeal cleft is a gap at the back of the larynx (or voice box) that may or may not be covered by a thin membrane. It’s likely that in patients whose trachea did not form normally before birth may also have abnormalities in the formation of the larynx. Food (especially liquids) can travel through this gap into the respiratory tract, resulting in aspiration. This can be a cause of choking during swallowing and respiratory complications such as recurrent pneumonia, even after repair of the tracheoesophageal fistula. A laryngeal cleft usually needs a special type of bronchoscopy called a suspension laryngoscopy or rigid bronchoscopy to diagnose it. Once diagnosed, it can be repaired surgically.

Some patients with EA also have another congenital abnormality called a Vascular Ring. A vascular ring consists of blood vessels in the chest which are located in places different from where they usually are. For example, the main part of the aorta, which is normally on the left side of the chest, may be located on the right side. These vessels can compress the trachea, esophagus, or both. This can lead to worse breathing problems or swallowing problems, and often worsen tracheomalacia. Vascular rings can be suspected at the time of bronchoscopy or upper endoscopy. They can sometimes be seen on the chest X-ray or a heart echocardiogram. The diagnosis is usually confirmed with a computerized tomography (CT) scan or magnetic resonance imaging (MRI) scan of the chest, with contrast dye. If the vascular ring is causing significant problems, it can be repaired using cardiac surgery.

Both the Esophagus and the Trachea

The tissues around the site of the original EA and TEF are not as strong as normal tissue, and sometimes break down over time. This can lead to a recurrent TEF. A recurrent TEF usually acts rather like an H-type TEF: sometime after the original repair, cough or choking with liquids, or recurrent pneumonias start happening. This can indicate the need to have the individual tested for a recurrent TEF.

Tom Kovesi MD, Pediatric Respirologist, Children’s Hospital of Eastern Ontario, Ottawa, Ontario Canada
26/12/2016

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