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ABSTRACT
Unilateral vocal cord paralysis causes disturbances with vocal function and swallowing, to include aspiration. Thyroplasty type I has become one of the preferred surgical treatments for unilateral vocal cord paralysis. It is tolerated better by the patient, improves predictability of surgical results, and provides good voice results when compared to more traditional procedures, such as teflon injection. Use of a premade thyroplasty implant has made it possible to accomplish permanent medial displacement of a paralyzed vocal cord, avoiding the complications of other surgical options. AORN J 75 (March 2002) 512-522.
The larynx (ie, voice box) is a tubular vestibule that connects the laryngopharynx with the trachea. It lies in the midline of the neck anterior to the fourth through sixth cervical vertebrae (ie, C4 through C6); however, it may be slightly higher during childhood and in females.1
ANATOMY AND PKYSIOLOGY
The anatomical features relevant to unilateral vocal cord paralysis consist of the larynx, cartilages, laryngeal ligaments, vocal folds, and laryngeal muscles, nerves, and vasculature. The three main functions of the larynx are to
* provide a passageway for air between the pharynx and the trachea,
* prevent aspiration and assist in coughing, and
* produce sound as a result of vocal cord vibration.
Cartilages. The skeletal framework of the larynx is composed of membranes and nine pieces of cartilage. There are three single cartilages (ie, thyroid, epiglottic, cricoid) and three paired cartilages (ie, arytenoid, cuneiform, corniculate) (Figure 1).
The thyroid cartilage (ie, Adam's apple) is the largest cartilage of the larynx and consists of two fused plates of hyaline cartilage. The thyroid cartilage is triangular in shape and forms the anterior wall of the larynx. The epiglottic cartilage is a leaf-- shaped piece of elastic cartilage that projects upward behind the tongue and hyoid bone. The inferior margin of the epiglottis is attached to the superior margin of the thyroid cartilage, but its free superior border can move up and down during swallowing to prevent food or liquids from entering the trachea.2 The cricoid cartilage is a ring of hyaline cartilage that forms the inferior wall of the larynx.3 Shaped similar to a signet ring, it is the only complete cartilaginous ring in the respiratory tract.
The pyramid-shaped arytenoid cartilages are the...