The surgical approach to an upper airway tumor depends on its location. Proximal tracheal lesions require resection of the trachea and possibly the cricoid cartilage or larynx. Segmental resection of the trachea with direct end-to-end anastomosis is used to remove tracheal main body lesions. Removal of tumors that involve the distal trachea, carina, or mainstem bronchus requires some form of carinal resection, with the extent of airway resection determining the mode of reconstruction. If the disease process involves the lobar orifices, resection can be accomplished by including contiguous resection of the affected lobes.1,2 Lymph nodes should be resected whenever possible for staging, although extended lymphadenectomy can devascularize remaining airway tissue and should be avoided.
Preoperatively, patients should stop smoking and be weaned from steroids 2 to 4 weeks before resection to avoid deleterious effects on anastomotic healing.1 Bronchoscopic techniques can be used, if needed, for temporary palliation for patients with severe obstruction while surgery is delayed. The anesthesiologist should place an epidural catheter preoperatively and have experience with complex airway management. Anesthetic management should include inhalation induction and short-acting medications to permit early extubation, which will decrease pressure on the airway anastomosis. For carinal resections, mediastinoscopy should be performed at the time of resection both for staging and to develop the pretracheal plane to improve mobility of the upper airway and lessen the chance of subsequent injury to the left recurrent laryngeal nerve when the distal trachea is dissected free at thoracotomy.1 Ventilation during airway resection is achieved by distal airway intubation with an armored-type endotracheal tube connected to sterile anesthesia tubing across the surgical field. A sterile camera bag also can be used to house the airway tubing that is passed across the surgical field. The endotracheal tube is pulled back into the proximal airway by the anesthesiologist before airway incision.
After the distal resection margin is incised and the airway is divided circumferentially, the distal airway is intubated by the surgeon while the anesthesia team switches to the sterile circuit. If necessary, both lungs can be ventilated separately for carinal resections.3 Either a double-lumen endotracheal tube or a long single-lumen tube with selective intubation of the contralateral mainstem bronchus or a bronchial blocker positioned in the ipsilateral bronchus can be employed for mainstem bronchi resections.4 If necessary, the ipsilateral lung can be ventilated across the operative field if single-lung mobilization is poorly tolerated. The size and inflexibility of double-lumen tubes can present difficulties in procedures that involve carinal resection, and the extra-long single-lumen tube advanced into a mainstem bronchus to provide single-lung ventilation is preferable.1 The remaining mainstem bronchus is intubated across the operative field as resection proceeds.1 For carinal resections, the original long endotracheal tube is advanced into the bronchus after the end-to-end tracheobronchial anastomosis is brought together, permitting uninterrupted ventilation during completion of the secondary anastomosis of the remaining bronchus to the trachea.
A great deal of teamwork between the surgeon and the anesthesiologist is required during these cases. Completing tracheal anastomoses will require removing and replacing the endotracheal tube, during which time the anesthesiologist will need to hold ventilation and also be responsible for keeping the surgeon apprised of the patient's status and the estimated timing for reinstituting ventilation. This cycle is repeated until the distal airway is reintubated. In cases where ventilation cannot adequately be performed, such as with near-complete airway obstruction, extracorporeal membrane oxygenation, or cardiopulmonary bypass via peripheral cannulation can be utilized to maintain patient stability during manipulation of the airway.5,6 Conversely and interestingly, upper airway resection via a cervical approach has been reported in which mechanical ventilation was not utilized at all. Twenty patients have been described as undergoing safe upper airway resection with an average resection length of 4.5 cm while awake and breathing spontaneously with the use of both cervical epidural anesthesia and local anesthesia.7 However, thus far, this approach has only been reported for the treatment of benign upper airway stenosis and not tracheal tumors or malignancies.
A red rubber catheter can be sutured to the tip of the original endotracheal tube for upper tracheal tumors in cases where withdrawal of the tube proximal to the anastomosis will result in extubation. The profile and hindrance to reconstruction of the red rubber catheter can be further reduced by passing a heavy suture through the tip, which then can be used as a “leader” to guide the tube back through the vocal cords for reintubation of the distal airway from above.
Complete resection at the time of the first operation is the goal to relieve airway obstruction and give the best chance for cure. Since the margins can extend beyond what is grossly visualized and palpable, especially with adenoid cystic carcinoma, intraoperative frozen sections of resection margins are very important. However, upper airway tumor resection involves a compromise between the need to obtain clear margins to prevent postoperative recurrence and preservation of airway length to reduce anastomotic tension and ensure adequate healing. The safe limits of tracheal resection often depend on sound clinical judgment and vary with age, neck mobility, and body weight. Thin patients with long necks generally can tolerate longer lengths of tracheal resection, as can younger patients because of greater tracheal elasticity. Less than complete tumor resection may be acceptable to provide a long period of symptom-free palliation if morbidity risks limit the operative choice, especially for radiosensitive tumors such as adenoid cystic carcinoma.8-10
Various techniques have been described for airway anastomosis. Absorbable sutures are used for all airway anastomoses to minimize the potential for granuloma formation. Either silk or Vicryl lateral traction sutures should be placed through the cartilaginous rings on the remaining proximal and distal airway segments as “traction sutures” to take tension off the suture lines when the sutures are tied. Our preferred technique is to use interrupted sutures of 4-0 Vicryl placed in the trachea, with the posterior membranous airway knots placed interiorly (Fig. 62-1A) and the anterior cartilaginous airway knots placed on the outside (Fig. 62-1B).11 It should be noted that the preferred technique at the Massachusetts General Hospital, where many of the airway surgery procedures were developed, is to use interrupted 4-0 Vicryl sutures, with all knots placed on the outside (Fig. 62-2).1 Other anastomoses with running sutures or a combination of running and interrupted sutures have been reported. In all likelihood, a successful anastomosis can be constructed if these central tenets are observed: preservation of airway vascular supply, tension-free apposition of the ends (perhaps secondary to the use of proximally and distally placed traction sutures and the appropriate release maneuvers), and accurate tissue approximation with absorbable sutures. Preclinical animal studies have reported that administration of platelet rich plasma and use of hyperbaric oxygen therapy improves anastomotic healing, though benefits of these treatments have not yet been reported in patients.12,13
Preferred method for anastomotic suture at our institution is to use interrupted sutures of absorbable 4-0 Vicryl (A) with the posterior membranous airway knots placed interiorly and (B) the anterior cartilaginous airway knots placed exteriorly.
Approach used at the Massachusetts General Hospital, with interrupted 4-0 Vicryl sutures, all placed exteriorly.
Almost half the trachea can be removed with a low-tension primary anastomosis when appropriate mobilization techniques are employed. Simple neck flexion may be the most useful single maneuver for reducing anastomotic tension. Dissection of the anterior avascular pretracheal tissue planes while preserving the blood supply in the lateral tissue pedicles, which can be performed via mediastinoscopy, permits some tracheal mobilization, especially distally. Because the tracheal blood supply is segmental, skeletonization of the proximal and distal tracheal ends should be performed for only approximately one tracheal ring, the extent needed to perform the anastomosis. Because extensive lymph node dissection can compromise the trachea and, ultimately, the anastomotic blood supply, it should be avoided. Additional methods can be used if the anastomosis appears to have excessive tension. Suprahyoid laryngeal release by separating the larynx from its thyrohyoid attachments is useful for achieving proximal tracheal mobility for resections that involve the proximal or midtrachea (Fig. 62-3). Postoperative aspiration precautions are needed after laryngeal release because some patients may have initial swallowing difficulties.8 The distal trachea can be mobilized by inferior pulmonary ligament division and mobilization of the right mainstem bronchus from the pericardium and the right main pulmonary artery and right superior pulmonary vein. The left mainstem bronchus may be divided and reanastomosed end to side with the right mainstem bronchus or bronchus intermedius to provide further mobility. Postoperatively, a heavy suture should be placed loosely from the inferior chin to the anterior chest wall and kept in place for 1 week to prevent inadvertent patient neck extension.1,11 The use of an orthosis fashioned from a fiberglass splint has also been described to prevent neck extension and alleviate patient discomfort from the tearing sensation that this suture can cause when patients inadvertently try to move their head.14
A. Suprahyoid laryngeal release is performed by separating the larynx from its thyrohyoid attachments to create proximal tracheal mobility for resections of the proximal or midtrachea. B. Appearance of trachea after laryngeal release.