Tracheal necrosis and surgical emphysema: a rare complication of thyroidectomy. (Original Article).

Abstract

We describe the first reported case of tracheal necrosis following a thyroidectomy. This complication resulted in massive subcutaneous emphysema and pneumomediastinum, which required emergency exploration of the neck to decompress the trapped air. We also discuss the suggested etiology and management of this rare condition.

Introduction

Tracheal necrosis is rare; only a few sporadic case reports have been published in the literature, all of which occurred in association with radiotherapy, chemotherapy, or localized sepsis. (1-5) Tracheal necrosis following a thyroidectomy has not been previously described. We report the first such case. Our patient developed tracheal necrosis during the early postoperative phase following a thyroidectomy and selective bilateral neck dissections. The patient also experienced massive subcutaneous emphysema.

Case report

A 62-year-old man was admitted for elective excision of a left thyroid mass. He was a lifetime heavy smoker and drinker, and he had disabling chronic obstructive airway disease. The thyroid mass had slowly enlarged over the previous 6 years. The patient was clinically euthyroid and had no evidence of dysphagia, hoarseness, or stridor. Flexible endoscopy confirmed a normal larynx, and his vocal folds were mobile and symmetrical. Preoperative ultrasound and magnetic resonance imaging detected a 1-cm tumor in the left lobe of the thyroid and metastases in multiple lymph nodes along the left sternocleidomastoid muscle and posterior triangle. Another cystic nodule was seen posterior to the trachea at the right suprasternal notch. Fine-needle aspiration cytology of the thyroid mass and left posterior triangle nodes detected atypical cells that were suspicious for papillary carcinoma.

The operation was carried out under general anesthesia. Intubation was complicated by laryngospasm and was initially achieved via an awake fiberoptic technique with a nasal tube. However, high ventilatory pressures led us to suspect tube malposition, so the nasal tube was replaced with an oral tube by using a stylet.

A total thyroidectomy and selective bilateral neck dissections (levels 2, 3, 4, and 6) were performed via a cervical apron incision. Upon completion, both recurrent laryngeal nerves were visibly intact. The trachea was leak-free on underwater testing and the anesthetist had not noticed any ventilatory leak.

On the fifth postoperative day, the patient developed swelling and erythema of the wound, which was presumed to be a wound infection and treated with ampicillin and flucloxacillin.

On postoperative day 10, following removal of his drains, the patient experienced an episode of vigorous coughing. Later that evening, surgical emphysema was noted over the right neck wound. This was thought to have arisen as a result of air passing into the neck via the drain site during the coughing. Despite conservative treatment (bed rest, pressure dressing, and cough suppressants), the surgical emphysema expanded, and by the following day, it involved the right supraclavicular area. The patient was not in respiratory distress but he did complain of retrosternal pain, On auscultation, a grating sound was heard in synchrony with the heartbeat. The patient's pulse and blood pressure were stable, and there were no distended neck veins, cyanosis, or other signs of circulatory failure. A chest radiograph detected extensive subcutaneous emphysema of the right neck and shoulder together with a pneumomediastinum (figure 1).

Because of concerns over airway obstruction and tension pneumomediastinum, the neck wound was explored urgently under general anesthesia. Raising of the flap revealed an obvious air leak; the second and third tracheal rings were found to be necrotic and damaged, as well (figure 2). A decision was made to create a stoma. The necrotic rings were excised and a fenestration was made in the anterior wall (figure 3). The stoma was fashioned by suturing the skin edges to the trachea of the first and third intercartilaginous membranes. Two large drains were placed and the wound was closed. Over the next 2 weeks, the emphysema gradually resolved. The patient was discharged on hospital day 28. Six weeks later, a follow-up examination revealed that the stoma had healed.

The histology of the excised tissue revealed an inflammatory change with no evidence of granuloma, acid-fast bacilli, or tumor infiltration. Analysis of the thyroidectomy specimen confirmed that the patient had had a papillary carcinoma; metastatic tumors were found in three nodes in the specimen of the left neck dissection. The patient was referred for radioiodine therapy.

Discussion

Airway disruption as a result of tracheal necrosis and perforation has not been previously reported as a postoperative complication of thyroidectomy. Etiologic factors that contribute to tracheal injuries and rupture following intubation are commonly classified as mechanical and anatomic (table 1). (6) In our case, both the intubation injury and the operative trauma (mechanical factors) were probably important contributing factors to the development of necrosis and the dissolution of the tracheal rings. Moreover, anatomic factors such as chronic obstructive airway disease (which might have weakened the trachea) and tumor infiltration of peritracheal tissue might have also aggravated the tracheal injury.

Experimental studies have shown that mechanical factors together with disturbances in the local blood supply can result in ischemic changes in the mucosa, connective tissue, and cartilage following a thyroidectomy. (7) Furthermore, cervical and upper mediastinal lymph node dissections made during an esophagectomy have been shown to induce ischemic changes that cause ulceration and necrosis in the tracheobronchial mucosa. (8) We therefore believe that the tracheal necrosis in our patient was initiated by the mechanical trauma of intubation and surgery and perpetuated by postoperative ischemia.

Once the patient developed the air leak, his situation might have been aggravated by the episode of vigorous coughing. The fascial planes that envelop the neck form a continuum that connects the chest and abdomen, and the air that accumulates in one of these locations can decompress into deeper structures, including the mediastinum. (9) Subcutaneous cervicofacial and mediastinal emphysema occurs when interstitial air is present in the soft tissues of the head, neck, and thorax. This condition can occur spontaneously (following alveolar rupture) or following traumatic disruption of mucosal or cutaneous barriers. (9-11) It can even occur as a result of an infection by gas-forming organisms. (10) The most common cause, however, is iatrogenic--that is, secondary to mucosal disruption during head and neck surgical procedures, endoscopy, and intubation. Cervicofacial emphysema can be exacerbated by increased airway pressure during sneezing, coughing, and positive pressure ventilation.

Isolated cervicofacial emphysema is usually painless; most patients complain of facial or neck swelling. The diagnosis is based on the history, physical examination, and radiologic investigations. The typical crepitus found on palpation will immediately distinguish subcutaneous emphysema from hematoma, edema, and abscess formation.

The most common symptom of pneumomediastinum is a stabbing precordial chest pain that radiates to the arms and back. Dyspnea is the second most common symptom, although respiratory distress is rare. Other symptoms include dysphagia, odynophagia, neck pain, dysphonia, otalgia, and hearing loss. Hamman's sign--a crunching sound synchronous with the heartbeat--is present in 50% of patients with pneumomediastinum. (10)

Radiographic findings include streaks or pockets of air in the subcutaneous region that often outline anatomic boundaries. For example, pneumopericardium can appear as a thin radiolucency along the cardiac border or aortic arch. This finding confirms the displacement of the parietal pleura within the mediastinum.

The natural course of subcutaneous cervicofacial and mediastinal emphysema is usually benign. Absorption of the air is usually complete within 2 weeks. However, this situation is associated with several serious complications, including pneumothorax,(10) cardiac tamponade and tension pneumomediastinum, (12) air embolism, (13) and mediastinitis and neck abscess (table 2). (14)

Treatment is directed at the underlying cause and any subsequent complications. Conservative management includes monitoring of vital signs, bed rest, analgesics, and sedatives. Tracheostomy is recommended for patients with airway compromise and progressive emphysema. (12,15) This procedure releases trapped air, secures the airway, and prevents further accumulation of air. In the rare situation of hemodynamic embarrassment caused by tension pneumomediastinum, surgical decompression of the mediastinum might be indicated. (12) The creation of a cervical fasciotomy and mediastinotomy via a low collar incision allows for effective mediastinal decompression. In our case, surgical exploration and the creation of a tracheal stoma secured the airway and primarily decompressed the neck and allowed the pneumomediastinum to resolve. This case represents a rare cause of surgical emphysema of the neck that required, and resolved with, prompt surgical intervention.

Table 1. Mechanical and anatomic factors that contribute to intubation
injury to the trachea

Mechanical factors                  Anatomic factors

Surgical trauma                     Congenital tracheal abnormalities
Multiple attempts at intubation     Extrinsic mediastinal compression
Inappropriate use of stylets        Structural weakening of the
Malposition of the tip of the tube   membranous trachea as a result
Overinflation of the cuff            of surgery, inflammatory lesions,
Vigorous coughing                    corticosteroid therapy, and/or
Abrupt head and neck movements       advanced age
Table 2. Complications of subcutaneous cervicofacial and mediastinal
emphysema (10-15)

Pneumothorax
Cardiac tamponade
Tension pneumomediastinum
Air embolism
Mediastinitis
Neck abscess

References

(1.) Sprinzl GM, Eckel HE, Ernst S, Motamedi K. Cricoid cartilage necrosis after arytenoidectomy in a previously irradiated larynx. Arch Otolaryngol Head Neck Surg 1999;125:1154-7.

(2.) Oppenheimer RW, Krespi YP, Einhorn RK. Management of laryngeal radionecrosis: Animal and clinical experience. Head Neck 1989; 1:252-6.

(3.) Gross CW, Gross IC. Rare complications after prolonged translaryngotracheal intubation. Ann Otolaryngol 1971;80:582-4.

(4.) Charlin B, Dchon A, Bergeron D, et al. Aseptic necrosis of the cricoid: A complication of tracheal intubation. J Otolaryngol 1987;16:377-81.

(5.) Melnyk A, Graham NJ, Weber D, Walsh GL. Lethal tracheal dissolution during treatment for thyroid lymphoma. Thorax 1995;50:1120-1.

(6.) Marty-Ane CH, Picard E, Jonquet O, Mary H. Membranous tracheal rupture after endotracheal intubation. Ann Thorac Surg 1995;60:1367-71.

(7.) Staindl O, Lametschwandtner A. [The pathogenesis of tracheal stenosis following thyroidectomy]. HNO 1979;27:260-6.

(8.) Kusano C, Baba M, Tanabe G, et al. [A study on the changes in the tracheo-bronchial mucosa after esophagectomy for esophageal cancer; with special reference to the influence of neck and upper mediastinal lymph node dissections]. Nippon Geka Gakkai Zasshi 1989;90:1866-72.

(9.) Minton G, Tu HK. Pneumomediastinum, pneumothorax, and cervical emphysema following mandibular fractures. Oral Surg Oral Med Oral Pathol 1984;57:490-3.

(10.) Maunder RI, Pierson DJ, Hudson LD. Subcutaneous and mediastinal emphysema. Pathophysiology, diagnosis, and management. Arch Intern Med 1984; 144: 1447-53.

(11.) Henry CH, Hills EC. Traumatic emphysema of the head, neck, and mediastinum associated with maxillofacial trauma: Case report and review. J Oral Maxillofac Surg 1989;47:876-82.

(12.) Kirchner JA. Cervical mediastinal emphysema. Arch Otolaryngol 1980;106:368-75.

(13.) Rickles NH, Joshi BA. Death from air embolism during root canal therapy. J Am Dent Assoc 1963;67:397-404.

(14.) Aragon SB, Dolwick MF, Buckley S. Pneumomediastinum and subcutaneous cervical emphysema during third molar extraction under general anesthesia. J Oral Maxillofac Surg 1986;44:141-4.

(15.) Pecora DV, Yegian D, Hochwald A. Tracheotomy in the treatment of severe mediastinal emphysema. JAMA 1958:166:354-6.

Reprint requests: Edward W.H. To, Oral and Maxillofacial Surgery Center, St. Teresa's Hospital, 327 Prince Edward Rd., Kowloon, Hong Kong. Phone: [phone]; fax: [phone]; e-mail: [e-mail]