The level of the mediastinal tracheostomy must be determined. The end of the distal trachea is gently drawn upward in the mediastinum, using the lateral traction sutures. If it is not well above the brachio-cephalic artery, elective division of the artery will have to be considered (see Figures 34-3A,5). This is not done lightly, but the hazards of erosion of the artery are great if the stoma lies at the last few centimeters of trachea above the carina. The surgeon should have obtained information about the patency of the carotid and vertebral arteries preoperatively. If it appears that the brachiocephalic artery might be endangered by proximity of the stoma, it is preferable to divide the artery. The brachiocephalic artery is temporarily occluded atraumatically and the electroencephalogram (EEG) is carefully observed over a period of 20 minutes. If there is no change in EEG pattern, it is usually safe to divide the artery. The artery is never ligated, but rather is divided, and the proximal and distal ends oversewn with two layers of vascular suture material. It is essential that the carotid-subclavian communication be intact on the distal side. In numerous cases of emergency and elective division of the artery, we have not seen neurological damage.8,9 One patient suffered from faintness following division when he stood up quickly, but this passed with time. Another patient, after division, complained of transient weakness in the right arm, when used for heavy work. F. G. Pearson (personal communication) reported a young patient who had transient neurological sequelae following brachiocephalic artery division.
The substernal colon or stomach is delivered to the left of the tracheal stump and pharyngoenteric anastomosis is performed (Figure 34-35). In the stomach, an appropriate linear incision is made, which is adequate for a broad anastomosis. The end of a colon segment may be used, but if it does not lie in easy apposition to the pharynx, the end is closed with staples, oversewn with interrupted 4-0 silk sutures, and the pharynx anastomosed to the side of the colon. Anastomosis is done with two layers of 4-0 Vicryl or silk sutures, using great care and precision in the placement of each suture. A posterior layer of sutures is placed first, prior to opening the replacement organ. After all posterior seromuscular wall sutures have been placed and tied, the replacement organ is opened and the full thickness of the mucosa and muscular wall of either the colon or stomach is sutured to the mucosal layer only of the pharynx. This inner layer is completed anteriorly with inverting sutures and then the anterior seromuscular outer layer of sutures is placed. With precise anastomotic technique and omental buttressing, leakage is unlikely, even where the proximal end has received high-dose irradiation in the remote past. The key here is that the distal side of the anastomosis and the omentum are unirradiated.
The omentum is delivered from beneath the sternum and spread out. If the stomach or colon and omentum are first placed in a flexible plastic bag (such as that used for sterilization of laser equipment), it greatly facilitates their delivery through the substernal tunnel. The omentum is divided into two tongues, taking care not to injure its blood supply. One is sutured against the pharyngoesophageal closure, or around the pharyngocolonic or pharyngogastric anastomosis, to buttress these sutures lines. The other wraps the trachea circumferentially beneath the stoma (Figure 34-3C). The omentum is carefully interposed between the trachea and innominate artery or its divided ends. It is essential that any vascular ends be buried in healthy tissue (see Figure 34-3C). The omentum serves several functions in respect to the trachea: it provides buffering between the trachea and the artery or its sutured ends; it provides healthy and unirradiat-ed tissue around the trachea, if the trachea has been irradiated; and it provides a seal, if the tracheal end separates from the skin in whole or in part postoperatively. This has effectively prevented brachiocephalic arterial hemorrhage. The omentum is sutured to the tracheal wall subterminally (see Figure 34-3C), leaving enough length for anastomosis to the skin and subcutaneous tissues.
The lower incision for creation of the bipedicled anterior cutaneous flap is made. It runs from the right to the left anterior axillary lines beneath the breasts (see Figure 34-1). The flap is raised from the sternum and the pectoralis muscles laterally, meeting the dissection plane from above. Retraction on either side permits lateral access. The surgical plane lies on the pectoral fascia to avoid injuring the blood supply to the flap. Perforating vessels are encountered and controlled. The fully dissected flap is slid upward and deeply into the mediastinal defect. A point in its midline is selected for emergence of the tracheal stoma. A circle of skin is excised, about equal to the size of the trachea (Figure 34-4A).
The subcutaneous tissues of the flap at the margin of the stoma are sutured to the tracheal wall, just below the cut end of the trachea and above the ring of omentum. These may be placed from beneath the flap and tied by palpation. The lateral traction sutures draw the tracheal stoma through the cutaneous opening and the subcutaneous sutures are tied. The endotracheal tube may be successively removed for convenience as the cutaneous anastomotic sutures are next placed. 4-0 Vicryl sutures pass through the skin margin and then through the full thickness of tracheal wall. Four sutures—one anterior, one posterior, and one at each lateral margin—are initially placed to align the anastomosis. Three to four sutures are placed figure 34-4 Completion of tracheostomy. A, Tracheostomy is implanted in a carefully-made circular excision in the skin flap. Anastomotic sutures are placed circumferentially between the skin and mucosa of the trachea, as described in the text. Subcutaneous sutures to the trachea are sometimes also used. The lateral tracheal stay sutures are removed as the tracheocutaneous sutures are placed. B, The completed stoma. C, The completed reconstruction. The central defect below the flap is covered with a split-thickness skin graft overlying intact chest wall. An attempt to close the skin primarily is likely to place undue tension on the margins of the mediastinal tracheostomy. Subcutaneous, cervical, and mediastinal drains are shown.
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