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figure 24-8 Division of the trachea and dissection of the stenosis. Note the traction sutures. A, In most cases, the trachea is circumferentially dissected below the stenosis, and the trachea divided and intubated distally. Traction on the lower end of the specimen facilitates posterior and lateral dissections from the esophagus. B, In a low-lying stenosis, it is more convenient to divide the trachea proximal to the lesion, dilate the stenosis directly if need be, and intubate through the stenosis. Traction on the specimen again facilitates posterior dissection until ready for distal tracheal division.

does not enter the lumen of the larynx (see detail). B, In the trachea, distal or proximal, the midlateral sutures pass around a cartilage, about one ring below the point of transection, and pass in and out of the tracheal lumen, as shown in detail.

In patients who particularly have stenosis related to the cuff of an endotracheal tube and who have not had a tracheal stoma, the external surface of the trachea may appear to be relatively normal, except for mild peritracheal fibrosis. The exact level of stenosis must be precisely localized intraoperatively, and not from earlier bronchoscopic measurement alone or from radiographs. A flexible bronchoscope is passed intraoperatively through the endotracheal tube, and the tube is withdrawn slowly under direct vision to a subglottic position. The bronchoscopist identifies the precise level of the lower end of the stenosis. With the operating field lights deflected, the area of tracheal transillumination is clearly seen. A no. 25 hypodermic needle is passed through the tracheal midline from the operative field, at what appears to be the distal margin of the stenosis. The bronchoscopist checks the position of the needle until it is precisely located (Figure 24-10). The outer tracheal wall is marked with a suture at this exact level. The upper end of the stricture may be similarly identified, although it will be easier to identify intraluminally once the trachea has been divided distally and the specimen elevated.

figure 24-10 Flexible bronchoscopic transillumination of the trachea to identify the borders of a stenosis not clearly identifiable externally. A fine needle is inserted and placed precisely at a margin of the lesion under visual bronchoscopic guidance, and the point marked by suture.

A flexible endotracheal tube with its connectors and sterile anesthesia tubing is clipped into place at the level of the incision, and the proximal anesthesia tubes are passed through the drapes to the anesthetist. Our staff dubbed these "elephant trunks." The peroral endotracheal tube is partly withdrawn and taped. The trachea is divided transversely. Care is taken to make this a clean cut, preferably but not necessarily, between cartilages. The distal trachea is intubated across the operative field, inflating the cuff just enough to obtain a seal. The traction sutures may be elevated and crossed over the tube where it lies, and fixed to the drapes or held by a second assistant. This keeps the tube in place without the need for tying or suturing it in place. The endotracheal tube and its attached "trunks" may be flipped up or down to improve access at different stages of operation, or the tube may be removed intermittently during anastomosis. Perelman suggested placing the anesthesia tube through a temporary and more distal vertical tracheostomy,1 but I have usually avoided this. Even when the cuff of the tube is inflated, the operative field and the distal trachea are suctioned frequently to minimize seepage of blood into the tracheobronchial tree. This is especially important in patients with marginal pulmonary function.

The specimen is grasped with Allis forceps on either side of its distal margin and elevated upward or to the side, as necessary (see Figure 24-8). The paired Allis forceps expose the plane of dissection more clearly. Dissection is completed with this exposure in areas of difficult scarring, until the proximal end of the area of stenosis is reached. Great care must be exercised proximally if the cricoid cartilage is approached. The recurrent laryngeal nerves enter the larynx, medial to the inferior cornua of the thyroid gland, against the broadened portion of the reverse signet ring of the posterolateral cricoid cartilage. Dissection is carried up to the palpable inferior margin of the cricoid cartilage where stenosis extends that high. As one elevates the specimen with traction, the esophagus may be dissected away from the trachea without injury. Care must be taken not to dissect posteriorly superior to the inferior margin of the posterior cricoid plate, since this is the point where the larynx and esophagus are attached, and also where the recurrent nerves enter the larynx posterolaterally. It is also important to have the anesthetist withdraw the endotracheal tube in high lesions so that one does not palpate the tip of the tube and mistake this for the cricoid plate. Indeed, for higher lesions, the bulk of the endotracheal tube may be very much in the way of the operator. I, therefore, usually suture a catheter into the leading tip of the endotracheal tube and ask the anesthetist to withdraw the

figure 24-10 Flexible bronchoscopic transillumination of the trachea to identify the borders of a stenosis not clearly identifiable externally. A fine needle is inserted and placed precisely at a margin of the lesion under visual bronchoscopic guidance, and the point marked by suture.

endotracheal tube from the larynx altogether (Figure 24-11). The catheter later serves as a guide to bring the endotracheal tube back down through the larynx, just prior to completion of the anastomosis. The narrow diameter of the catheter does not interfere with visualization of the interior of the airway.

When the proximal end of a tracheal stenosis has been reached, dissection is carried a little further in order to make place for lateral traction sutures and to prepare a margin for suturing. Obviously, if this is the cricoid cartilage itself, then minimal further dissection is performed. Dissection is often required for a short distance laterally between cricothyroid muscles and the upper pole of the thyroid gland. More posterior dissection is not useful and can endanger the recurrent laryngeal nerves. In this case, the midlateral traction sutures (2-0 Vicryl) are placed in the larynx itself, obtaining a good firm bite in the lateral cricoid cartilage laminae, since purely muscular sutures will pull out. Sutures thus placed in the larynx do not enter the lumen (see Figure. 24-9A).

figure 24-11 Use of a catheter as a "leader," which will be used to draw the endotracheal tube back through the larynx. A, Heavy suture passed through the tip of the endotracheal (ET) tube and through the catheter, 1 to 2 cm from its tip. B, The suture fixes the "leader" to the leading tip of the ET tube so that it will not be caught on the vocal cord as it is pulled distally through the larynx.

figure 24-11 Use of a catheter as a "leader," which will be used to draw the endotracheal tube back through the larynx. A, Heavy suture passed through the tip of the endotracheal (ET) tube and through the catheter, 1 to 2 cm from its tip. B, The suture fixes the "leader" to the leading tip of the ET tube so that it will not be caught on the vocal cord as it is pulled distally through the larynx.

If the stenosis is low in the trachea, it is more convenient initially to dissect circumferentially around the trachea, proximal to the lesion. This permits division of the trachea, where it is easily accessible. The endotracheal tube across the operative field passes through the stenosis into the distal trachea (see Figure 24-85). The stenosis is dilated, if necessary. Uterine or common duct dilators serve well. Allis forceps placed on either side provide good traction to complete the distal dissection. With the brachiocephalic vessels gently retracted forward, a benign stenosis located even at the supracarinal level may be resected by this approach. With very distal stenoses, lateral traction sutures may be placed with minimal difficulty at the tracheobronchial angles and, later, the anastomotic sutures. In such cases, intubation is usually made into the longer left main bronchus after the specimen is removed, ventilating one lung only. High frequency ventilation may be used, either with a single or bifid catheter. This approach is worthwhile, in order to avoid the discomfort of a thoracotomy, and it is essential in patients with a low tracheal stenosis, who suffer from severe chronic obstructive pulmonary disease and who could not safely undergo thoracotomy. A complete sternotomy does not provide better exposure than a partial one, since dissection lies behind the great vessels. A transpericardial approach is not necessary here.

With careful dissection, it is extraordinarily rare to enter the esophagus. However, in patients with circumferential cuff lesions, the stenosis may be densely adherent to the esophagus and dissection must be precise. If there was any likelihood of injury, then methylene blue in a large volume of saline should be instilled into the esophagus through a high nasogastric tube for direct inspection. An esophageal injury is meticulously closed in two layers (see Chapter 26, "Repair of Acquired Tracheoesophageal and Broncho-esophageal Fistula") with an overlying buttress of pedicled strap muscle.

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