TSRA Content:
Author: Daniel P. Dolan, MD
This is a revision and update from the previous edition of the TSRA Primer in Cardiothoracic Surgery written by Muhammed Masood, MD
Introduction
The previous chapter reviewed the most common types of esophagectomy as well as the abdominal sequence common to all procedures. Here we will review the cervical and thoracic stages of the operation.
Regardless of approach or type of anastomosis, the general conduct of the operation should ensure atraumatic handling of tissues, sharp transection of the esophagus to prevent stricture, a straight gastric conduit (with the staple line to the patient's right side), a well-perfused conduit, and sufficient length of conduit to allow for a tension-free anastomosis.
Cervical Stage (Transhiatal/ Modified McKeown)
The left neck is preferred because of the more reliable and vertical course of the left recurrent laryngeal nerve (RLN) compared to the right. Injury to the RLN occurs by excessive traction by metal retractors (avoid the use of these medially), thermal injury from electrocautery, or excessive superior retraction on the trachea causing longitudinal stretching of the nerve.
The neck is typically prepped into the field at the same time as the abdominal portion of the procedure. A 5-6 cm incision is made along the medial border of sternocleidomastoid muscle (SCM). Alternatively, a transverse incision two finger-breaths above the sternal notch and extending from the midline laterally across the SCM may be used. Platysmal flaps are raised and the SCM is mobilized posteriorly. Strap muscles are retracted medially. The anterior belly of the omohyoid muscle may be retracted superiorly or divided to improve proximal exposure.
Dissection is carried down medially to the IJ and carotid. The middle thyroid vein and inferior thyroid artery may be divided if needed for exposure. Note that distal branches of the inferior thyroid artery are intimately involved with the RLN and can put traction on the nerve when the vessels are retracted laterally and the trachea medially. The thyroid lobe is retracted medially; because of the thyroid attachments to the trachea, this maneuver will retract the airway as well. Avoid superior retraction, causing longitudinal traction on the nerve.
Dissection is then carried posteriorly towards the spine. Blunt dissection is performed with a finger pointing posteriorly to the spine, followed by a medial finger-tip rotation, thus developing the plane between the prevertebral fascia and the esophagus. A NGT can help to identify the esophagus when performing this blind, blunt dissection.
With the posterior aspect freed, the esophagus can be hooked with the dissecting finger and retracted laterally to the left, allowing better visualization for dissection of the anterior aspect. Using a right-angle instrument and hugging the esophageal muscle, the anterior aspect is dissected from left to right until the finger hooking the esophagus is reached, thus completing the circumferential dissection. A Penrose drain can then be looped around the esophagus and used for traction as dissection is carried proximally and then distally into the thoracic inlet where the mediastinal dissection plane is met.
The RLN travels more anteriorly in the tracheoesophageal groove as it courses distally in the neck, decreasing the chance of injury as dissection is carried into the inlet. Care should also be taken to avoid injury to the posterior membranous portion of the trachea during dissection of the anterior aspect of the esophagus. The key to avoiding injury to surrounding structures during this stage is to keep the dissection directly on the esophagus.
Once the conduit has been delivered from below, the anastomosis can then be created (described later in this chapter). The neck is closed in layers and a closed suction drain placed next to the anastomosis.
Thoracic Stage
Whether approached via thoracotomy, thoracoscopy, or robotic, the fundamentals to safe dissection are the same.
Mobilization and creation of an intrathoracic anastomosis is typically performed through the right chest, typically via a thoracotomy in the 5th intercostal space or thoracoscopically with ports placed as previously described. After the right lung has been isolated, the inferior pulmonary ligament is divided to allow retraction of the lung superiorly and anteriorly. Mobilization begins on the anterior aspect of the esophagus by opening the mediastinal pleura at a point just posterior to the inferior pulmonary vein and extending superiorly along the junction of the mediastinal pleura and the lung. Loose areolar and lymphatic tissue is swept toward the esophagus as it is mobilized on its anterior and medial aspects.
Dissection is carried superiorly from the inferior pulmonary vein in the avascular plane along the pericardium. The bronchus intermedius is then encountered, which is traced back to the right main stem bronchus and subcarinal lymph node packet. The entire lymph node packet is then removed en bloc, at which point the left mainstem bronchus should be seen. Care must be taken to avoid excess use of energy in this area to minimize the risk of thermal injury to the airway. Bleeding is commonly encountered during this dissection and can be controlled with clips.
The pleura is opened to the azygous vein, which is commonly divided. The Vagus nerve should be divided close to the esophagus at the level of the azygous vein to avoid traction injury to the RLN. Dissection above the azygous vein should be kept close to esophagus, also to minimize the risk of RLN and airway injury. The mediastinal pleura overlying the posterior aspect of the esophagus is then opened from diaphragm to thoracic inlet.
Posterior mobilization is then continued until the anterior/medial plane of dissection is met. Liberal use of clips posteriorly is advised to control the numerous lymphatic and aortoesophageal branches that are encountered. Unless performing a thoracic duct lymphadenectomy or routine resection of the duct (radical lymphadenectomy), the posterior dissection should stay close to the esophagus.
Once the esophagus has been circumferentially mobilized, the conduit is pulled up further into the chest and detached from the specimen if an intrathoracic anastomosis is to be made (described below). Additional esophageal mobilization may be facilitated by retracting the specimen toward the head. After pulling back the NGT, the proximal esophagus is transected at the desired level, typically above the azygous vein. If there is concern for the proximal margin, intraoperative endoscopy should be performed for confirmation. The specimen is then removed and sent for frozen section analysis of the esophageal and gastric margins. The intrathoracic anastomosis is then performed. A closed-suction drain is typically placed near the anastomosis in addition to chest tubes. If a cervical anastomosis is planned, the esophagus is not transected and only mobilization is performed.