What Is Subglottic Stenosis?
Subglottic stenosis is a narrowing of the subglottis (the area of the windpipe just below the vocal folds. This narrowing is most often made of scar tissue.
What Are the Symptoms of Subglottic Stenosis?
In adults, the most common symptom is stridor, a high-pitched noise during inspiration (breathing in) or expiration (breathing out) or both. This sound is often misinterpreted as wheezing. In fact, most patients with subglottic stenosis are first misdiagnosed as having asthma. Patients often have shortness of breath with exertion.
What Causes Subglottic Stenosis?
Subglottic stenosis can be related to previous intubation (having a breathing tube placed in the throat for surgery or respiratory distress). While this is most common with prolonged intubation (several days), it can occur after short durations of intubation as well. Subglottic stenosis can also occur after trauma to the area. It can also be associated with some autoimmune disorders (specifically Wegener's) or it can be idiopathic (of unknown origin). It is thought that gastrointestinal reflux may play a role in the development of subglottic stenosis because it causes irritation and inflammation of the airway.
How Is Subglottic Stenosis Diagnosed?
Subglottic stenosis can be suspected on pulmonary function tests (a test wherein the patient breathes into a machine to measure how much air he or she can move in and out). It can be seen on a CT scan of the neck. In the office or operating room a scope can be placed into the trachea (windpipe) to visualize the stenosis.
How Is Subglottic Stenosis Treated?
Patients will usually be placed on anti-reflux medication.
Surgically, there are several ways that subglottic stenosis can be treated. The least invasive way is an endoscopic dilation (widening of the narrowed segment performed through the mouth). Various instruments can be used to widen the airway including metal scopes, lasers (to cut open the narrowing), balloons (to stretch the narrowed area), or stents (plastic or metal to hold the area open).
Some individuals may be a candidate for a cricotracheal resection (a larger procedure performed through an incision in the neck in which the narrow segment is removed and the ends of the airway sewn back together).
Finally for some individuals a tracheotomy (a breathing tube is placed in the neck/trachea below the level of the narrowing) is required.
The approach that your surgeon chooses may be influenced by the location, length and duration of the narrowing. In addition, any associated medication problems that you may have can influence the choice of procedure. Because the stenosis is usually made of scar tissue, with any of these interventions there is a tendency for scar tissue to reform. Patients often need multiple procedures to manage this disease.
What Is the Difference Between Tracheal Stenosis and Subglottic Stenosis?
The biggest difference between tracheal and subglottic stenosis is the location of the narrowing. Tracheal stenosis occurs lower in the trachea (windpipe) and is more commonly associated with trauma to the airway, i.e. intubation or previous airway surgery. Subglottic stenosis in higher, just below the level of the vocal folds and is more often idiopathic (of unknown origin) or associated with autoimmune disease. In addition, the subglottis (the area just below the vocal folds) is naturally the most narrow point in the adult airway. To resect subglottic stenosis can prove more difficult because of the close proximity to the vocal folds.
What About Infants With Subglottic Stenosis?
Subglottic stenosis in infants is most commonly associated with intubation in the neonatal ICU. These infants often require tracheostomy (a breathing tube placed in the neck) placement in the neonatal period. They may also have lung disease related to prematurity. Endoscopic dilations can be performed on these infants when they are toddlers and older children. Open surgical repair usually requires a laryngotracheal reconstruction in which a segment of rib cartilage is used to widen the area. This can be done in a single surgery in which the tracheostomy (breathing tube in the neck) is removed at the time of surgery or in two stages in which the tracheostomy is removed at a later date.