Excerpt from Trachea, Stenosis

Synonyms, Key Words, and Related Terms: upper airway stenosis, stenotic trachea, tracheal trauma, laryngotracheal stenosis

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Background: The causes of adult laryngeal and upper tracheal stenosis are trauma, chronic inflammatory diseases (amyloidosis, sarcoidosis, relapsing polychondritis), benign neoplasm (respiratory papillomatosis), malignant neoplasm (primary tracheal, secondary invasion, metastatic), and collagen vascular diseases (tracheopathia osteoplastica, Wegener granulomatosis). The most common cause of laryngotracheal stenosis continues to be trauma, which can be internal (prolonged endotracheal intubation; result of tracheotomy, surgery, irradiation; endotracheal burns) or external (blunt or penetrating neck trauma).

In the authors' experience, prolonged endotracheal intubation is the leading cause of laryngotracheal stenosis, which occurs mainly in patients with multiple trauma or in those who have undergone cardiovascular surgery.

In 1880, Macewen first reported endotracheal intubation for anesthesia and, in 1969, Lindholm reported injuries to the larynx and trachea after intubation for this purpose. Tracheal lesions caused by pressure from the cuff of the tube have now been almost eliminated with the use of high-volume, low-pressure cuffs. However, the number of intensive care patients who require intubation and artificial ventilation has increased dramatically.

Pathophysiology: The sequence of events that leads to stenosis involves ulceration of the mucosa and cartilage, inflammatory reactions with the granulation tissue, fibrous tissue formation, and contraction of fibrous scar tissue. Capillary perfusion pressure is a crucial consideration in mucosal injury. Mucosal ischemia is produced by direct contact with a segment of an endotracheal tube or by an increase in the pressure in the tube cuff.

The earliest laryngotracheal injury produced by an endotracheal tube is ulceration; basically, ulcer healing involves regeneration of the epithelium (primary healing) or repair (secondary healing). In the process of ulcer healing, if the epithelium fails to cover the granulation tissue, the growth of granulation tissue becomes exuberant. This tissue has 2 forms: pseudopapillary granulation and nodular granulation. After weeks or months, the granulation tissue that was once vascular becomes an almost avascular scar that contains only a few widely separated blood vessels.

Frequency:

In the US: Tracheal stenosis affects 4-13% of adults and occurs in 1-8% of neonates after prolonged intubation. Primary tracheal tumors are rare.
Recurrent respiratory papillomatosis most commonly involves the larynx, but other areas of the respiratory tract may be involved. Tracheobronchial involvement usually is secondary to contamination after tracheotomy. Some authors consider them the most common benign laryngeal tumor.
Sarcoidosis involves the larynx in 5% of patients and the trachea in 1% of the cases, and remains a diagnosis of exclusion. Laryngeal or tracheal involvement occurs in 50-70% of the patients with relapsing polychondritis. In Wegener granulomatosis, tracheobronchial involvement occurs in 10-20% of the patients.

Mortality/Morbidity: Severe congenital laryngotracheal or benign acquired stenosis requires immediate airway intervention, but less than one half of the patients with congenital lesions require tracheotomy. Individuals may seek medical care only after repeated episodes of laryngotracheal infections or with exercise intolerance.

Race: To the authors' knowledge, the prevalence does not depend on race.

Sex: To the authors' knowledge, the prevalence does not depend on sex.

Age: Postintubation tracheal stenosis is uncommon in children. Congenital stenosis is even more uncommon.

Anatomy: Gross anatomy and vascular supply

The trachea occupies the anterior and middle part of the .....