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