The intraoperative preparation depends on the surgeon's technical preferences. For surgeons who consider dividing the innominate artery, arrangements may be made for intraoperative electroencephalography after the artery has been clamped. Arterial line monitoring, nasogastric tube drainage, a Foley catheter, and two large-bore peripheral intravenous lines are ideal. Jugular and subclavian lines may interfere with the operative field. Close coordination between the surgeon and the anesthesiologist is required to safely obtain an airway prior to the surgery. Furthermore, after division of the trachea, it is ideal to have the appropriate tracheostomy available. The tracheostomy used for this procedure has a low-pressure, high-volume balloon with a short distance of tubing distal to that balloon.
Positioning, Incisions, and Tracheal Exposure
The patient is positioned supine with the head extended on a cushioned head support and the scapula on a folded blanket. One arm may be abducted for arterial or venous access. A left-sided radial arterial line is ideal if there is any chance of dividing the innominate artery. Sterile preparation may extend from the chin to the pubis and midaxillary line bilaterally. The abdomen is included if esophageal substitution or omental wrapping of the tracheostomy is planned. The thighs may be prepared as well for a potential split-thickness skin graft or vein graft.
The common incisions used for MT are the extended collar incision and the bipedicled/apron incision (Fig. 65-3).1,2 When the tracheostomy is being performed for a recurrence in the tracheostomy site, the peristomal skin must be resected and a rotational pectoralis flap is necessary (Fig. 65-3C). The preferred incision is the extended collar incision. However, if there is any hint of tension at the tracheocutaneous anastomosis, we perform a rotational pectoralis flap and prepare the thigh for a split-thickness skin graft for the residual defect.
Three commonly used incisions. A. Collar incision. B. Bipedicled (apron) incision. C. Pectoralis rotational flap often used for recurrence in a tracheostomy site.
The surgeon's first goal is to assess the appropriateness of the procedure before proceeding with potentially irrevocable actions such as resecting the breastplate. Occasionally, the surgeon may find either that the tumor is unresectable or that tracheal reanastomosis is possible with adequate mobilization.
Using the extended supraclavicular collar incision (Fig. 65-3A), bilateral subcutaneous platysma flaps are created exposing the strap muscles superiorly. The carotid sheaths, sternum, and hyoid bone are exposed. The sternocleidomastoid muscles and carotid sheaths are displaced laterally. Unilateral vessel involvement by tumor is not a contraindication, because they can be divided and reconstructed. The anterior trachea, posterior trachea, and prevertebral fascia are exposed while preserving the important lateral blood supply of the trachea. For tracheal tumors, the prevertebral space is bluntly dissected, ruling out invasion of the vertebral column and the pharynx superiorly. In general, invasion of the larynx and either the esophagus or the trachea within the thoracic inlet necessitates an MT to obtain adequate margins for cure.
The inferior flap is developed after declaring the need for MT. The goal of this flap is to expose the breastplate, including the upper sternum, clavicle, and the first two ribs (Fig. 65-4). The muscular insertions (i.e., straps and sternocleidomastoid) are divided to expose the sternum, clavicle, and ribs. The decision to extend the resection down to the second rib depends on the level of anticipated tension on the tracheocutaneous anastomosis. If there is any doubt, the upper sternum and second rib should be resected.
The breastplate is resected along with the first one or two ribs. Depending on the final tracheal length, sometimes only the clavicle, manubrium, and first rib are resected. However, it is more usual to include the second rib and the superior portion of the body of the sternum. In the technique shown here, both the manubrium and upper body of the sternum have been resected for better visualization.
First, the mammaries are protected and isolated by locating them at the level of the second rib. Next, the midline pectoralis fascia, from the sternal notch to the angle of Louis, is bisected with electrocautery. The pectoralis muscle then is elevated off the first two medial costochondral joints. The sternum is transected transversely just above the third rib. By elevating the sternum with bone hooks, underlying structures can be swept away. The pectoralis flap will be used to cover the wound defect later. The upper sternum and manubrium are bisected with the electric saw. The mammary and subclavian veins are swept clear, and the Gigli saw is used to encircle the first and second cartilages individually and to divide the medial thirds in a subperiosteal plane. Our technique for resecting the clavicle and first rib includes the precaution of sliding a ribbon between the Gigli saw and the subclavian vessels. The sawing sound changes if the “protective” ribbon is encroached. The free breastplate is removed.
Tracheal Division and Laryngectomy
After the breastplate has been removed, the surgeon prepares to divide the trachea. A complete node dissection appropriate to the tumor should be done. The innominate vein is preserved unless invaded directly. The level of tracheal division is determined by considering the margins and whether the goal of the particular surgery is palliative or curative. A Penrose drain may be passed behind the specimen portion of the trachea to facilitate further exposure (Fig. 65-5). Again, attention should be paid to preserving the lateral blood supply of the remaining trachea and stoma (Fig. 65-6, inset). Circumferential devascularization of the trachea (particularly within 1–2 cm of the transected edge) should be avoided to prevent peristomal breakdown and mediastinitis. Prior to division, stay sutures are placed at the inferior tracheal margin. The trachea is divided obliquely at the inferior margin. This facilitates the tracheocutaneous anastomosis such that it may curve anteriorly flush with the skin (Fig. 65-5, inset). After division, it is reintubated (Fig. 65-6) with sterile tubing across the field. The tracheostomy tube is secured with stay sutures to the trachea and to the skin. To preserve the airway, the inferior division is dealt with first. Next, the superior division usually is made at the level of the thyrohyoid membrane, preserving the hyoid bone. The larynx then is oversewn with running sutures. Total or partial thyroidectomy may be required depending on the extent of tumor involvement. All efforts should be made to preserve a parathyroid, with reimplantation if necessary. If there has been prior radiation, however, this may be difficult.
The trachea and surrounding structures are exposed and divided. Reintubation immediately follows the distal division, and the proximal division occurs later. Note how the trachea is divided obliquely (inset). This leaves as much posterior membranous trachea as possible to reach the anterior chest wall surface.
After the airway is divided, it is secured with an endotracheal tube. The surgeon bluntly develops the avascular plane posterior to the trachea and anterior to the esophagus. Note how deviation in either direction laterally threatens the blood supply to the mobilized trachea (inset).
Transposition of the Trachea
Tension on the trachea as it reaches the anterior chest wall and skin may result in complications, including peristomal breakdown leading to mediastinitis and even fatal postoperative innominate artery rupture. For this reason, if there is any doubt, we and other authors strongly recommend transposition.2,3 The standard MT will rest interposed between the innominate artery and the left carotid artery (Fig. 65-7). With transposition, the trachea will follow a shorter path to the skin by coursing to the right of and underneath the innominate artery. Thus, its path lies between the innominate artery and the superior vena cava (Fig. 65-8). Although we do not recommend it, innominate artery division is another option for patients who can tolerate it (Fig. 65-9). This can be demonstrated with preoperative angiogram or even intraoperative electroencephalogram after clamping for 10 minutes. It may be best suited when the distance from the carina to the end of the remnant trachea is less than 5 cm.1 After transposition, we recommend wrapping the trachea as it passes underneath the artery with a well-vascularized strap muscle. Other options include omentum or pectoralis muscle. The most important factor, however, is that the trachea is well vascularized and reaches the skin without any tension. Wrapping the trachea will not prevent arterial rupture if there is significant tension.
The normal position of a mediastinal tracheostomy.
If the trachea does not appear to reach the new “depressed” chest wall, then either more sternal body may be resected, or the trachea may be transposed to the right of the innominate artery. The transposed trachea should be wrapped with viable tissue such as a strap muscle to help reduce the likelihood of innominate artery rupture.
Other options to decrease tension include dividing the innominate vein or artery. Before dividing the innominate artery, it should be clamped and tested with electroencephalography.
Tracheocutaneous Anastomosis and Closure
The route of the trachea to the anterior skin must be secured, wrapped, and buttressed by all available tissue. With the exception of the specific strap muscle that protects the innominate artery (in tracheal transposition), all muscles should be reapproximated with interrupted absorbable sutures. As the cervical incision is sutured closed, the tracheocutaneous anastomosis is begun. It must be secured to the skin with full-thickness skin and subcutaneous purchases as well. This is done in an interrupted fashion (Fig. 65-10). A few absorbable sutures may be placed from the subcutaneous tissue to distal trachea to reduce the tension on the tracheocutaneous anastomosis.1 Drains are placed beneath the inferior and superior flaps and for any alimentary tract anastomoses. If there is a defect in the apron incision, a split-thickness skin graft can be used for coverage (Fig. 65-11).
In making the tracheocutaneous anastomosis, the trachea is secured to the inferior flap of skin with the endotracheal tube in place. To reduce tension, a rotational myocutaneous flap always can be created.
Note the depressed chest wall in the closure of the collar incision (A) and in the apron incision (B). A skin graft can be used to cover the inferior defect in the apron incision.
At this point, if there appears to be any tension, there are several options. A button of skin can be excised below the transverse incision, and the trachea can be brought out through this new defect.2 In this scenario, we prefer to use the pectoralis rotational flap. Development of the pectoralis flap began when it was lifted off the chest wall before the breastplate resection. This thoracoacromial “nipple” flap (Fig. 65-12) can be done, even in patients without a tracheostomal recurrence.
A. Rotational myocutaneous flap. This can be used to cover large defects (as in tracheostomal recurrence) or to reduce tension. The blood supply comes from the pectoral branch of the thoracoacromial artery. B. A skin graft covers the inferior defect (inset).
A thoracoacromial flap is used most often in a patient with laryngeal cancer who suffers recurrence at the stoma site. In these patients, the surrounding skin is resected (Fig. 65-3C). However, it also may be performed after a standard extended collar incision if there is tension at the end of the case. Simply extend the incision inferiorly along the sternum and around the inframammary crease (Fig. 65-3C) to the preferred side. Both pectoralis muscles will have already been lifted off the chest wall in the prior dissection. The rotated muscle is based on the thoracoacromial vessels. A split-thickness skin graft can cover the remaining defect (Fig. 65-12).