Preparation and Positioning
The patient is positioned supine. Arterial line, oxygen saturation probe, and venous catheter placements are guided by the possibility of division of the innominate artery and sacrifice of the left innominate vein. Similarly EKG pad placement may be affected by resection of the primary cancer or harvesting of reconstructive flaps. EEG leads may be placed for monitoring if there is concern of compromising cerebral perfusion. Techniques and equipment necessary for endotracheal intubation will be determined by the primary cancer and presence of an established tracheostomy. Provisions must be made for cross-table ventilation during surgery.
The operative field is prepared and draped from patient's chin to suprapubic abdomen and bilaterally to midaxillary lines. The thigh and forearm/arm may be included in the field if they will be used for flap harvesting or skin grafting.
The operation starts with a collar incision placed above the sternal notch. The incision should be positioned to permit extension laterally, if necessary, over the clavicles and inferior over the manubrium (Fig. 66-1). If a tracheostomy exists, the stoma should be included in the incision. Invaded or radiation-damaged skin is excluded from the flaps, excised, and left attached to the cancer. The superior subcutaneous flap is raised above the hyoid bone, and the inferior flap is lifted to the sternal notch. Cranial, caudal, lateral, and deep invasion are assessed during this mobilization. If uninvolved the strap muscles are then separated in the midline or if invaded they are divided and left attached to the primary cancer. Lateral dissection determines if the carotid sheath is involved by the cancer. The prevertebral space is developed to assure the resection can be completed posteriorly. These steps confirm cancer resectability and to this point no irreversible steps have been taken.
A collar incision is made above the sternal notch with inclusion of the tracheostomy stoma if one exists.
Typically, the resection begins inferiorly. If a mediastinal tracheostomy is necessary, the incision is extended in the midline inferiorly over the manubrium. The lateral myocutaneous flaps are raised off the bony chest wall, and the manubrium is excised along with the first and second cartilages and the clavicular heads (breast-plate). The level of tracheal division is selected. The trachea is circumferentially mobilized at this site and lateral dissection restricted below this point. Lateral traction sutures are placed in the tracheal wall one cartilage below the anticipated position of tracheal transection (Fig. 66-2). This will stabilize the trachea and facilitate tracheal intubation during cross-field ventilation. Once the trachea has been divided and distal intubation obtained, the tracheal margin is sent for frozen-section analysis. Some thyroid and airway (adenoid cystic carcinoma) cancers may not involve or minimally invade the esophagus, permitting esophageal preservation without compromising the resection. In patients requiring cervical exenteration the point of esophageal transection is determined. The extent of the primary cancer and the method and organ of esophageal reconstruction will dictate this level. If free flap is being used for reconstruction, the esophagus is divided in the low neck and this margin is sent for frozen-section analysis.
The tumor is exposed by raising the superior subcutaneous flap above the hyoid bone and lifting the inferior flap up to the sternal notch. The tumor is inspected for invasion both superiorly and inferiorly. Lateral dissection determines if the carotid sheath is involved by the tumor. The trachea is mobilized circumferentially. Lateral traction sutures are placed in the tracheal wall one cartilage below the anticipated position of tracheal transection.
The dissection proceeds superiorly. The prevertebral plane, already assessed, is now easily developed. Laterally the dissection is carried along the carotid sheaths. Rarely unilateral sacrifice of the internal jugular vein is required. If unilateral carotid excision is required, arterial reconstruction or bypass will be necessary. If the thyroid is not involved, the isthmus is split and one or both sides are preserved and allowed to remain in the lateral resection margins. If not radiated this practice preserves thyroid and parathyroid function. If possible resected parathyroid tissue that is uninvolved with the primary cancer may be autotransplanted and this position marked with radiopaque clips.
The superior margin of the resection is now defined. The superior border of the hyoid bone is cleared of the attachments of the mylohyoid, geniohyoid, and genioglossus muscles. Lateral muscular attachments of the larynx are divided and the superior laryngeal neurovascular bundle controlled and divided (Fig. 66-3). The pharynx is entered anteriorly and the superior resection proceeds posteriorly. The epiglottis is incorporated in the resection specimen. The superior resection margin is sent for frozen-section analysis.
The superior margin of the resection is defined, and the superior border of the hyoid bone is cleared of the attachment of the mylohyoid, geniohyoid, and genioglossus muscles. Lateral muscular attachments of the larynx are divided, and the superior laryngeal neurovascular bundle is controlled and divided.
The two main methods of pharyngoesophageal reconstruction involve either GI transposition (stomach or colon) or microvascular free flaps (jejunum or myocutaneous). The general approach is to use gastric or colonic transposition for cancers that extend to or below the thoracic inlet and free flaps for the short-length reconstruction required by cancers arising above the thoracic inlet.2–4 However, in any one institution the experience may be so small that one of these methods may become the reconstruction of choice.
If division of the trachea is well above the sternal notch, a cervical tracheostomy stoma can be constructed. However, if tracheal division is at or below the sternal notch or if the operation is performed for tracheal stomal recurrence, a mediastinal tracheostomy will be necessary.5,6 The anterior breast-plate is excised. Erosion of the innominate artery, a major complication of mediastinal tracheostomy, can be avoided by separating the tracheal stoma from the innominate artery. If the stoma will be positioned immediately adjacent to the artery, elective division and oversewing of the ends under EEG monitoring has been reported.7 However, transposing the trachea below and to the right of the innominate artery also has been successfully used to avoid this dreaded complication.8 Division of the innominate artery must be placed proximal to the carotid-subclavian bifurcation.
The omentum can be used to cover anastomoses, separate innominate artery stumps from the trachea, and tracheal wrapping below the stoma.9 If there is significant soft tissue resection and wound closure is problematic a benefit of using myocutaneous free flaps is the ability to reconstruct both GI and soft tissue defects with the flap.10–12