Key Points

• The posterior aspect of the cricoid cartilage supports the arytenoid cartilages and vocal cords.
• The subglottic space is the narrowest part of the airway below the larynx.
• Postintubation injury is the most common cause of subglottic stenosis.
• During resection, identification of the recurrent laryngeal nerves is not necessary if dissection of the trachea is maintained immediately against the outer surface of the airway.

The subglottic airway extends from the inferior margin of the vocal cords above to the lower border of the cricoid cartilage below. Resection of the subglottic airway is complicated by the following factors:

1. It is in close proximity to the vocal cords.
2. Complete transection of the subglottic airway at any level above the cricothyroid joints will divide the recurrent laryngeal nerves.
3. The posterior rim of the upper border of the cricoid cartilage supports the arytenoid cartilages, which play a critical role in vocal function.

The technique of subglottic resection, which is described in detail later, allows transverse division of the airway up to the level of the inferior border of the vocal cords without transection of intact recurrent laryngeal nerves. At the level of the inferior border of the posterior cricoid plate, the recurrent nerves pass behind the cricoid cartilage. On each side, the nerve passes behind the cricothyroid articulation and continues a vertical ascent to the superior border of the cricoid cartilage, at which point it passes forward to supply the glottic muscles. As long as the tissues lying behind the cricoid cartilage are undisturbed, both recurrent laryngeal nerves can be predictably preserved.