12.09.06 Tracheo-oesophageal fistula

Definition

    • Malformation that arises from defective separation of the oesophagus and trachea

    • Most commonly results in a blind-ending upper oesophageal pouch with a fistulous connection between the distal oesophageal segment and the trachea

    • Gross classification

      • Type A

        • Pure atresia (4% to 7%)

      • Type B

        • Proximal fistula with distal atresia (1%)

      • Type C

        • Proximal atresia with distal fistula (85% to 90%)

      • Type D

        • Proximal and distal fistula (3%)

      • Type E

        • H-type fistula (2% to 3%); tracheoesophageal fistula without esophageal atresia

Risk factors

    • Trisomy 18 and 21

    • Family history

Differential diagnosis

    • Laryngeal cleft

      • These patients can present with symptoms similar to an H-type fistula with cyanotic spells, feeding difficulties, and recurrent chest infections

      • Best differentiated from a tracheo-oesophageal fistula by rigid bronchoscopy and oesophagoscopy

Epidemiology

    • One in every 3,000 births are affected, with a slight female preponderance

    • The majority of infants have Gross type C

      • 85% to 90% of all cases

      • Diagnosis typically occurs at or shortly following birth due to the blind proximal pouch

    • The second most common type is a pure atresia (Gross A), which comprises 4% to 7% of all tracheo-oesophageal fistulas

    • Gross type D occurs 3% of the time

    • A much rarer form, the H-type fistula (Gross E), occurs in approximately 2% to 3% of cases

      • This type of fistula may be undiagnosed until later in life

    • Type B occurs only 1% of the time

Aetiology

    • The trachea and oesophagus arise from the common foregut

      • Initially starts as a common tube, then separates into 2 distinct tracheal tubes

    • The trachea has primitive lung buds at the caudal end of the primitive trachea

    • The separation starts during the 4th week of gestation

      • A failure of normal division can result in various defects including atresias and fistula formation

    • This failure in organogenesis may be secondary to a failure of gene expression

      • Suspected genes include Sonic hedgehog homologue (Shh), a key developmental gene or possibly other genes involved in development of the respiratory tract

      • Other genes include:

        • Forkhead box (FOX) gene family

        • Sry-related HMG box (SOX) gene family

        • Zinc finger protein (GLI2)

Clinical features

    • Maternal hx of polyhydramniosis

    • Inability to swallow secretions

    • Inability to pass nasogastric tube

    • Laboured respiration

    • Coughing

    • Choking

    • VACTERL syndrome

    • (Cyanosis)

Pathophysiology

    • When oesophageal atresia is present, the infant is unable to swallow any liquid, including his or her own secretions

    • The baby cannot drink until either the atresia is repaired or the stomach is accessed via the anterior abdominal wall, or if a fistula is present, a connection between the airway and the alimentary tract

    • In type C, this connection can cause gaseous distension to form between the stomach and small bowel on x-ray

    • In rare cases, there is an associated intestinal atresia, which can lead to over-expansion and rupture of the stomach

    • Gastric contents can also reflux back through the fistula and cause aspiration, resulting in a chemical and bacterial pneumonitis

    • Motility of the oesophagus is always affected, with the distal segment having the most marked disordered peristalsis

    • There is also a lower resting pressure of the lower oesophageal sphincter resulting in a higher incidence of GORD

Investigations

    • Prenatal ultrasound

      • Polyhydramnios and a small or no stomach bubble

    • X-ray chest and abdomen

      • Nasogastric tube coiled in upper pouch

    • Bronchoscopy

      • Presence of a fistula

    • Oesophagoscopy

      • Presence of a fistula

    • Barium swallow

      • Contrast in trachea

Management

    • The majority of patients require surgery to ligate the fistula and establish oesophageal continuity

    • The condition is not compatible with life as the patient cannot eat and is at significant risk for aspiration

    • Patients with pure atresia and no fistula also require surgery but can be managed either by direct gastric feeds or IV hyperalimentation with a delayed repair of the oesophagus

    • Type A

      • Surgical oesophageal repair at birth is often challenging

      • However, without a connection to the trachea, these patients are less susceptible to acute respiratory distress

      • First-line patients may be managed with a nasogastric tube in the upper oesophageal pouch, providing continuous suction

      • Within the first few days of life, a gastrostomy tube is placed to allow for enteral feeds and the stomach contrast study to identify the length of the lower pouch

      • Bronchoscopy is mandatory in cases of isolated atresia (gross A) to rule out an upper pouch fistula (10% -15% of cases)

      • If the length between the proximal and distal oesophageal segments is 4 vertebral bodies or longer, then the patient is allowed to grow prior to attempting a repair

      • Growth is monitored by using contrast radiographs

      • If the gap between the proximal and distal segments of the oesophagus is less than 2 vertebral bodies, primary oesophageal repair can be performed immediately or around 2 to 3 months of age

      • Standard therapy includes a right thoracotomy, although this procedure is now performed thoracoscopically

      • Thoracoscopic treatment is available in limited centres and only for experienced endoscopists

      • In cases of a very long gap, various techniques have been designed to stretch or increase the oesophageal length

      • In some cases of a failed oesophageal repair or an extremely long gap, oesophageal replacement surgery is planned.

    • Type B

      • These patients cannot eat and are at risk for repeated aspiration of oral secretions due to a proximal fistula

      • The patients can be managed initially by a suction catheter in the upper oesophageal pouch which should limit secretions going into the trachea

      • Surgery should take place in the first 24 to 48 hours of life to ligate and divide the fistula and establish oesophageal continuity

    • Type C

      • The first-line treatment is with surgical correction, aimed at dividing the tracheo-oesophageal fistula to prevent lung aspiration

      • Then, anastomosis of the 2 oesophageal ends is completed, in order to establish continuity of the oesophagus

      • Classically, this procedure has been performed via a right thoracotomy incision but is now performed in many centres using a thoracoscopic approach

        • Avoids the inherent morbidity of a thoracotomy

      • This operation should be performed within the first 24 hours of life to prevent complications of aspiration and abdominal distension

      • Before surgery, the patient is stabilized by placement of a nasogastric tube to decompress the upper blind pouch

    • Type D

      • This type is extremely rare and involves not only oesophageal atresia but fistulas in the proximal and distal pouches

      • A suction catheter should be placed prior to surgery to decompress the upper pouch and limit the secretions entering the trachea

      • Surgical management includes division of the fistulas and an anastomosis of the proximal and distal oesophageal pouches

    • Type E

      • These patients often present in late childhood or in early adulthood with evidence of choking, gagging or recurrent aspiration

      • Once diagnosed, the patient should be kept nothing by mouth until the fistula is divided

      • Through a right neck incision at the level of the thoracic inlet, fistula repair is performed

      • The fistula can also be reached thoracoscopically through the right chest

Prognosis

    • Patients with isolated tracheo-osophageal fistula without commonly associated congenital abnormalities (i.e., cardiac and chromosomal) have a good prognosis and survive to live healthy lives

    • Motility disorders and respiratory complications may occur

      • In one study, 58% of adults with infantile repair had GORD