With malignant tumors, the goal of surgery is relief of obstruction as well as possible cure. Radiation alone will usually lead to recurrence within several years with squamous cell carcinoma as well as adenoid cystic carcinoma. What if there are localized pulmonary metastases with tracheal squamous cell carcinoma versus adenoid cystic carcinoma? Because of the long clinical course of adenoid cystic carcinoma and less aggresive nature compared to squamous variety, resecting an obstructing tracheal lesion for adenoid cystic may be justified with limited pulmonary metastases. It is hard to justify this with squamous cell carcinoma, however. It is important in patient selection to avoid the need for ventilatory support postoperatively. This is because in a shortened postresection trachea, the en-dotracheal tube cuff may rest against the anastomosis increasing the chance of dehiscence.
With regard to tracheal reconstruction, it should be noted that anatomic mobilization is crucial to achieving an adequate anastomosis that will not dehisce. Mobilization is achieved in one of several ways. The first is simple dissection around the trachea. This should not be extensive and should not extend more than 2 cm beyond the proposed margin of the resection. In particular, it is important to avoid dissecting in the lateral plane of the trachea so as not to devascularize it. Another extremely imp ortant maneuver is to flex the neck which will deliver almost the entire cervical trachea into the mediastinum. Thus all patients who undergo tracheal resection should have their neck flexed and their chin sutured to the anterior chest wall. Another way to further immobilize the trachea is to free the hilus of the right lung and to divide the inferior pulmonary ligament. The hilar mobilization is accomplished by freeing the pulmonary vessels from their pulmonary attachments. These maneuvers are most useful during surgery of the lower half of the trachea where generally a right thoracotomy is performed. It has been reported that these maneuvers as well as cervical flexion will allow up to 5 to 6 cm of trachea to be removed by the transthoracic approach. Another maneuver that may improve mobilization is the laryngeal release. In this approach, which is shown in Figure 24.1 a-c, the attachments holding the larynx to the myelohyoid are transected. This is accomplished by transecting the muscle attachments to the superior surface of the hyoid, then transecting the lesser corner of the hyoid bone, thus separating the hyoid bone from the myelohyoid. This permits an additional several centimeters of mobilization to be achieved. All in all, a resection of one-half of the entire trachea, i.e. about 6 cm, can be achieved with primary reconstruction.
The anesthesia of patients with trachea obstruction is critical. Cardiopulmo-nary bypass has been used for tracheal surgery but is not needed for most cases. The endotracheal tube should be passed beyond the level of the lesion and this may at times require dilation or coring out the tumor with a rigid bronchoscope. The trachea is transected distal to the lesion so that an airway can be introduced across the operative field directly into the distal trachea. Lesions in the upper half of the trachea that are known to be benign are best approached using a cervical collar incision. It may be necessary to prepare for a cervical mediastinal and possibly thoracic approach as well. If more exposure than can be achieved with a cervical approach is necessary, then the collar incision should be extended down to a partial median sternotomy. The upper sternum is split for a part of its length and horizontal division of the sternum is performed into the interspace. The incision sometimes needs to be extended through the fourth interspace on the right to allow for mobilization of the hilus of the right lung to further release the trachea. This permits wide exposure of the entire trachea. Lesions in the lower half of the trachea are usually approached through a fourth interspace, right posterolat-eral thoracotomy.
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