Radiation Induced Laryngeal Injury NJ



The larynx has multiple functions, including voice production, cough, and airway protection. The larynx also acts as a conduit for breathing. Pathologic conditions that affect normal laryngeal function can result in poor cough production, aspiration with subsequent pneumonia, change in phonation, and dysphagia. Chondronecrosis of the larynx is a rare complication encountered in otolaryngology.

Incidence may have increased more recently with the increased use of chemotherapy and radiation. When present, chondronecrosis can have severe sequelae. Causes include radiation therapy, relapsing polychondritis, long- and short-term intubation, infection, trauma, tracheotomy, and neoplasms.

Radiation is the most common cause of chondronecrosis. Many patients with head and neck cancer receive radiation therapy, which attempts to preserve the larynx and its aerodigestive function. Radiation therapy has expected mild adverse effects, but the development of chondronecrosis can result in morbidity and even mortality. Once developed, laryngeal chondronecrosis generally is irreversible. Laryngectomy is often required because of life-threatening laryngeal instability. Any etiology resulting in chondronecrosis of the larynx may cause instability and subsequent airway limitation and possible obstruction. Recognition of perichondritis may prevent progression to chondritis and necrosis. Careful evaluation, early detection, and timely intervention therefore are essential for laryngeal preservation.

Radiation therapy for squamous cell carcinoma of the larynx has become increasingly safe and effective over the last 50 years. The incidence of severe reactions following 5000-6000 rads has decreased from 5-12% in 1970 to approximately 1% in the 1990s. Complications from radiotherapy (RT) typically occur following a latent period of approximately 6 months. The most common complication, persistent laryngeal edema, occurs in 13.7% of patients who receive a dose less than 7000 centigrays (cGy) but rises to 46.2% with doses of 7000 cGy and above.

Radiation therapy has been shown to cause reactive fibrosis and endarteritis. This leads to vascular compromise, depletion of nutrient supply, and tissue hypoxia of dependent cartilages. In 1963, Alexander showed 3 histologic changes that occur: (1) venous subintimal fibrosis and hyalinization, (2) arterial degeneration of elastic fibers in the tunica media, and (3) hyalinization of smooth muscle fibers. This ultimately leads to a decrease in the reparative capacity of normal tissue.

Treatment

Treatment of radiation-induced laryngeal chondronecrosis can lead to total laryngectomy, preventing an attempt at organ preservation. Factors such as continued smoking, gastroesophageal reflux, diabetes mellitus, and arteriosclerosis have been implicated as etiologies that may exacerbate the condition. Initial management in Chandler grades I and II cases consists of inhaled steam, corticosteroids, antireflux medications and precautions, and antibiotics.

Patients with airway instability secondary to chondroradionecrosis may not be candidates for medical therapy. In such cases, tracheotomy is necessary. If the larynx is dysfunctional with life-threatening aspiration or functional with biopsy findings positive for recurrent carcinoma, laryngectomy is recommended. Persistent laryngeal edema for longer than 6 months is a clinical indication of persistent cancer and frequently leads to laryngectomy.

Complications

In the early stages (Chandler I-III), the airway cannot be protected, resulting in aspiration, pneumonia, and lung abscess. Furthermore, early stage chondronecrosis can progress to life threatening obstruction secondary to collapse, requiring emergent tracheotomy. Tracheal collapse resulting in sudden death has been reported in relapsing polychondritis. Other complications include dysphagia, odynophagia, and hoarseness.

With early recognition and medical intervention, the outcome and prognosis is good. In the case of chondroradionecrosis, frequent examination is recommended to detect an early manifestation of recurrent cancer.

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