The use of cricotracheal resection in the treatment of cancer is rare owing to the rarity of cancers of the subglottis and their lack of confinement to the larynx. Of the three subsites of the larynx, the subglottis is the origin of squamous cell carcinoma (by far the most common cause of laryngeal cancer), in only 1% to 3% of patients.¹ Cricotracheal resection for the treatment of subglottic stenosis is much more common, and the surgical techniques used for treating subglottic stenosis can be applied to surgical resection of the rare neoplasm that remains confined to the subglottis.

The glottis is defined by the American Joint Committee on Cancer as the superior and inferior surfaces of the true vocal cords occupying a horizontal plane 1 cm in thickness extending inferiorly from the lateral margin of the ventricle, including the anterior and posterior commissures. The subglottis is defined as that region which extends from the lower border of the glottis to the lower margin of the cricoid cartilage.² On the basis of histologic sectioning of whole larynges, Kirschner³ was able to demonstrate that the conus elasticus represents the definitive anatomic boundary between the glottis and the subglottis. Tumors above the plane of the conus elasticus tend to behave as glottic tumors and remain within the confines of the larynx, whereas those below the conus spread more easily beyond the borders of the larynx and metastasize more commonly to the prelaryngeal, paratracheal, and mediastinal lymph nodes.^1,4 The epithelial lining also can be used to differentiate the glottis (lined by keratinizing squamous cells) from the subglottis (lined by ciliated respiratory epithelium).

Although squamous cell carcinoma arises in the subglottis in only 1% to 3% of all laryngeal cancers, the subglottis is involved by contiguous spread of tumors of glottic origin in 11% to 33% of patients. These more common tumors are not amenable to cricotracheal resection.⁵ Early primary subglottic carcinomas are asymptomatic. Patients generally present with stage T3 or T4 tumors (Table 63-1), and airway obstruction is relatively common. These tumors usually exhibit circumferential growth, early cartilage invasion, and tumor growth beyond the borders of the larynx. Since glottic tumors with subglottic extension are not amenable to cricotracheal resection, and primary tumors of the subglottis of grade T2 or above are not contained within the subglottis, cricotracheal resection for squamous cell carcinoma is only possible for the rare T1 tumor. Otherwise, subglottic squamous cell carcinoma is treated with either radiation therapy or wide-field surgery, such as laryngectomy or laryngopharyngectomy. Tracheal tumors rarely extend superiorly to involve the subglottis. There is also strong evidence that subglottic squamous cell carcinomas should be treated aggressively, as there are poor outcomes published with advanced disease, and there is a propensity for nodal and distant metastasis.¹

Unlike the glottis, the subglottis contains laryngeal mucous glands and can be the primary site of tumors that arise from these glands. Nonsquamous laryngeal carcinomas make up only 1% to 5% of laryngeal cancers. They consist of adenocarcinoma, adenoid cystic carcinoma, mucoepidermoid carcinoma, neuroendocrine tumors, and cartilaginous tumors. In addition, plasmacytomas, non-Hodgkin lymphoma, and metastatic lesions can arise in the subglottis. Although different tumors require varying margins of resection and may respond to radiation with different efficacies, the selected early nonsquamous cell carcinoma may be resected by cricotracheal resection if the correct conditions exist. Perhaps best suited for cricotracheal resection is the chondroma or chondrosarcoma, the most common laryngeal sarcoma, representing 1% of all laryngeal tumors.⁶ Because the low-grade form of chondrosarcoma is easily confused with the benign chondroma, the true incidence is difficult to know. Chondrosarcomas arise from the hyaline cartilages of the larynx, and most commonly arise from the cricoid (70%), especially the posterior lamina, followed by the thyroid cartilage (20%), and the arytenoids (10%).⁷ Endoscopically, chondrosarcomas of the posterior cricoid lamina tend to grow into the airway, causing obstruction, and rarely, they extend beyond the confines of the perichondrium. As a consequence of the unresponsiveness of low-grade chondrosarcomas to radiation therapy and their confined growth patterns, cricotracheal resection with voice preservation can be accomplished.⁸ This often occurs after multiple endoscopic resections have failed to ameliorate the recurring airway obstruction. Paragangliomas and granular cell tumors of the subglottis are also amenable to cricotracheal resection.

Laryngotracheal invasion by thyroid carcinoma has an incidence of 7%.⁹ Invasion of the thyroid and cricoid cartilages occurs through direct extension and represents a rare but important cause of death from well-differentiated thyroid carcinoma. Controversy exists over the treatment of locally invasive thyroid carcinoma. “Shaving” the tumor from the larynx and trachea, followed by treatment with ¹³¹I, produces good long-term control of the disease, but this technique is only effective if no gross residual tumor is left behind.¹⁰

Subglottic and superior tracheal stenoses remain the most common indications for cricotracheal resection, and the principles of this technique are easily applied to surgical resection of the rare amenable neoplasm. Mechanical ventilation from endotracheal intubation remains the most common etiology of laryngeal stenosis.¹¹ Mucosal injury by either the tube or the balloon cuff results in either ischemia from pressure or mucosal tears from movement or placement of the tube. These iatrogenic events can lead to mucosal ulceration, perichondritis, chondritis, and finally, cartilage necrosis. The injury can occur at the glottic, subglottic, or tracheal levels and is largely preventable by early tracheotomy and aggressive adjunctive management, such as antibiotics and proton pump inhibitors. Laryngotracheal stenosis can also be caused by autoimmune diseases, infection, scar formation post tracheotomy, and idiopathic causes. Subglottic stenosis can be found in 16% to 20% of patients with Wegner’s granulomatosis.¹² In our own practice, having treated more than 80 patients with Wegner’s granulomatosis and subglottic stenosis, we find that endoscopic treatment of the stenosis, including direct injection of steroid and balloon dilation has prevented the necessity of tracheotomy or open airway reconstruction in all patients.¹³ In previously treated patients, especially in those who have undergone multiple endoscopic laser excisions, we have had to resort to open laryngotracheal reconstruction.

Tracheal and subglottic damage is often due to tracheotomy tube injuries. Inappropriately high tracheotomies, migration of the tube superiorly, and suprastomal granulation tissue are common causes of failure to decannulate patients after tracheotomy.¹⁴ The cause of the superior migration is unknown but may be due to movement from swallowing or external neckties that pull the tube superiorly. These patients often are amenable to cricotracheal resection but are challenged by extensive damage of the trachea and cricoid from chronic infection caused by microbial colonization of the tracheotomy tube, in addition to the concurrent disease that necessitated the tracheotomy in the first place. Contraindications in our own practice for cricotracheal resection for tracheotomy removal include poorly controlled diabetes, systemic steroid therapy, likely need for intubation in the near future, obstructive sleep apnea, and concomitant pulmonary disease. Similarly, poorly controlled diabetes, systemic steroid therapy, and severe pulmonary disease are contraindications to cricotracheal resection for neoplasms of the subglottis, and nonsurgical treatments such as radiation therapy, chemotherapy, and palliative therapy are best suited to patients with significant comorbidities.

Office assessment of the patient includes flexible nasal fiberoptic endoscopy to exclude glottic involvement, vocal fold fixation and posterior commissural interarytenoid stenosis, and impending airway compromise. Fine-cut CT scan determines cartilage invasion and extralaryngeal spread, as well as cervical lymphadenopathy. Three-dimensional reconstruction and “fly through” radiologic endoscopy can further define the pathologic process. It is our practice to use full-body CT/PET to exclude regional and distant disease. Combined endoscopy under general anesthesia including direct laryngoscopy with biopsy, bronchoscopy, and esophagoscopy permit tissue diagnosis, debulking, determination of the inferior extent of the tumor, and exclusion of esophageal spread posteriorly. Patients should be warned that their voice will be hoarse for some period postoperatively and that the quality of their voice may differ permanently with a decrease of fundamental frequency of approximately 10 Hz. This effect can be even more pronounced in women as shown by Smith et al.¹⁵ with a mean decrease in fundamental frequency of 21 Hz in the 14 women they evaluated having undergone cricotracheal resection. The reason for this decrease in fundamental frequency is that the cricothyroid muscle is resected at its attachment to the anterior cricoid ring, resulting in an inability to tense the vocal fold which is the normal physiologic function of the cricothyroid muscle.

Figure 63-1 demonstrates the common technique of cricotracheal resection for circumferential subglottic stenosis. This technique is described not only for use by surgeons wishing to resect stenoses but also for those wishing to excise tumors of the subglottis, as demonstrated in Figure 63-2. In most cases of subglottic tumor resection, the mucosa and submucosa overlying the posterior plate of the cricoid needs to be resected. In some amenable tumors, partial vertical height of the cricoid must be resected to obtain suitable margins, preserving enough posterior cricoid cartilage superiorly and between the arytenoids to preserve arytenoid stability. If the mucosa is resected up to the interarytenoid area, or if a limited margin exists inferior to the true vocal fold, laterally hindering normal vocal fold movement, a laryngofissure is created not only to permit adequate exposure but also to incorporate the use of a stenting T-tube around which healing occurs, preventing postoperative glottic stenosis (Fig. 63-3).