Diverticula of the thoracic esophagus are relatively uncommon and typically account for <30% of all esophageal diverticula. As stated earlier, their classification according to location or pathogenesis is probably unnecessary because midesophageal traction diverticula are now a rarity in the Western hemisphere. Almost all thoracic esophageal diverticula are associated with and perhaps caused by an esophageal motor disorder, most commonly achalasia, diffuse esophageal spasm, hypertensive lower esophageal sphincter, and nonspecific motor disorders. Using cinefluorography and manometry, Cross et al. concluded that in 150 patients with esophageal disorders, esophageal diverticula were the result of excessive intraluminal pressures. This segmental increase in pressure, caused by increased esophageal tone or a delay in sphincteric opening, acts on weakened areas of the esophagus and results in outpouching of the mucosa.
Most patients are >60 years of age, and many are asymptomatic or have only minimal and often vague symptoms. There is usually no correlation between diverticular size and the presence of symptoms. Many vague symptoms may be attributable to the underlying motility disorder rather than the diverticulum. Symptoms include dysphagia, postural regurgitation, belching, retrosternal pain, heartburn, and epigastric pain. As in pharyngoesophageal diverticula, pulmonary symptoms are often present but underestimated. These symptoms range from mild nocturnal cough to life-threatening massive aspiration.
Indications for Surgery
Most would agree that surgical intervention is necessary in symptomatic patients, those with large diverticula, and those with established complications such as bronchopulmonary infection (Fig. 22-5
). The indication for surgery in asymptomatic or minimally symptomatic patients is less clearly defined by the literature, and yearly surveillance for patients with an asymptomatic thoracic esophageal diverticulum is often the most prudent option.
The basic elements of the operation are resection of the diverticulum and a myotomy to alleviate the underlying motor disorder. Although some authors advocate that a myotomy be done only if a documented underlying motor disorder is present, this is a hazardous proposition because it risks the integrity of the diverticulectomy staple line in the postoperative period and a possible recurrence of the diverticulum later. Another point of controversy is the length of the myotomy. Although a limited myotomy may be satisfactory in many situations, a long myotomy from the level of the aortic arch down to the first 1 cm to 2 cm of the stomach adds little to the duration of the operation and essentially eliminates the need for reoperation. Naturally, once the cardia is mobilized, a nonobstructive type of antireflux repair must be added to avoid the almost certainly ensuing gastroesophageal reflux, which the aperistaltic esophagus cannot adequately clear.
All patients receive a preoperative dose of ampicillin/sulbactam, and this antibiotic is continued for 24 hours postoperatively. Patients with large diverticula should have the contents of the sac evacuated by a large tube preoperatively. Rapid sequence induction of general anesthesia is necessary to secure rapid control and protection of the airway against aspiration.
Notwithstanding that most diverticula project into the right side of the chest, the preferred approach is through a left thoracotomy, which permits excellent exposure of the lower half of the thoracic esophagus, the diverticulum, and the cardia should an antireflux repair be necessary. The patient is placed in the right lateral decubitus position, and the left chest is entered through the sixth intercostal space. The use of a double-lumen endotracheal tube with deflation of the left lung greatly improves the exposure. The mediastinal pleura is incised over the esophagus, the incision extending from the aortic arch to the esophageal hiatus. The esophagus is mobilized at some distance away from the diverticulum and encircled proximally and distally with Penrose drains including both vagus nerves (Fig. 22-6
). The sac is freed from the surrounding mediastinal structures with blunt and sharp dissection. Occasionally, the sac is firmly adherent to the right lung or the right mainstem bronchus (in midesophageal diverticula), and upward traction on the esophagus allows a careful dissection of the sac from those attachments.
Figure 22-5. Large epiphrenic pulsion diverticulum associated with pain and intermittent regurgitation of undigested food.
The sac may be invested in an inflammatory rind of tissue, and this must be carefully removed to expose the submucosal wall. The neck of the diverticulum is sharply dissected from the surrounding esophageal muscle and residual scar if present, and the submucosal layer should be separated from the surrounding overlying muscle at its margins so that the true neck is obvious for later division. The vagus nerves may be very adherent to the sac, and can be embedded in the inflammatory tissue surrounding it. Care must be taken not to injure the nerves during this part of the procedure.
Dissection then proceeds caudally to mobilize the gastric cardia. The phrenoesophageal membrane is sharply divided, and the hiatus is manually dilated. The mobilization of the cardia is completed by dividing the posterior attachments between the two vagi and entering the lesser sac, followed by complete excision of the fat pad just superior to the cardia in this region. The posterior attachments here may harbor an enlarged arterial branch emanating from the left gastric artery, and failure to recognize this can result in hemorrhage.
At this time, a 44-F or larger bougie is placed by the anesthesiologist with manual guidance by the surgeon past the diverticular opening. The diverticulum is then brought into view by grasping its fundus with an atraumatic clamp and rotating the diverticulum and the esophagus anteriorly and then to the left (Fig. 22-7
). If possible, a diverticulectomy is now performed by excising the sac about 5 mm from its neck using a linear stapling device. If this is not possible due to the size of the neck or necrosis at its junction at the esophageal wall, it can be sharply excised after placement of stay sutures on the cranial and caudal extents of the neck. This can then be repaired using interrupted 3-0 absorbable sutures. A nasogastric tube is passed, and the stapled closure is tested for leak by air insufflation under water with distal esophageal compression. The muscle layer is then approximated over the mucosal closure with interrupted 3-0 silk sutures (Fig. 22-8
). On occasion, the muscular layer may be too edematous
or attenuated for a good second-layer closure. If this is the case, an intercostal muscle flap may be mobilized and approximated to the linear repair using interrupted small silk sutures on the muscular margins. If this is necessary, placing it around the esophagus posteriorly and then onto the left anterior surface will facilitate comfortable position when the esophagus is rotated back to the right. A long myotomy is then performed on the left lateral aspect of the esophagus 180 degrees from the excised diverticulum. The muscle is divided at least 2 cm proximal to the diverticular repair, and if feasible from just below the aortic arch and carried across the gastroesophageal junction onto the stomach for approximately 1 cm. The edge of muscle is gently dissected off the underlying mucosa for several millimeters on either side to preclude premature healing of the myotomy. A nonobstructive antireflux repair should then be performed to prevent reflux sequelae. The repair of choice is the Belsey Mark IV partial fundoplication, with sutures placed on either side of the myotomy in the muscular layer. Once the second layer of sutures is placed, the cardia is gently repositioned into the abdomen and the second layer of sutures is tied. The crura are reapproximated with large nonabsorbable suture so that it will accommodate the tip of the operator’s index finger, and the nasogastric tube is advanced into the stomach.
Figure 22-6. Mobilization of the esophagus for thoracic diverticulum. Penrose drains are used to encircle the esophagus proximal and distal to the diverticulum, including vagus nerves. (n. = nerve.)
Figure 22-7. The esophagus is rotated to the left and anteriorly to expose the diverticulum, which is most often located on the right side. (n. = nerve.)
Minimally invasive treatment of thoracic esophageal diverticula has been performed, but the laparoscopic approach should not be used for those diverticula that are positioned higher near the inferior pulmonary vein. When this approach is feasible, a Dorr fundoplication is the preferred procedure after resection of the diverticulum and myotomy. Thoracoscopic approaches have also been reported, and the components of the operation are no different from the open procedure described previously, with the caveat that very large diverticuli may be difficult to dissect and rotate into the field adequately. These minimally invasive techniques are attractive, although the relatively rare nature of these lesions as symptomatic or very large lesions at presentation has precluded systematic study of this approach.
Surgical Complications and Postoperative Care
Retention of the nasogastric tube is encouraged for 3 to 4 days, at which time a barium esophagram is performed to rule out leak at the repair or myotomy or mechanical obstruction. If no leak is present, a clear liquid diet is begun and is rapidly advanced to a soft mechanical diet with discharge typical on the sixth or seventh postoperative day. Although success rates are very high, there has been moderate morbidity reported and a mortality of up to 9% in some series, substantiating the recommendation that small or asymptomatic diverticula should be observed. Causes of death are more frequently mediastinitis as a result of esophageal leakage and aspiration pneumonia. Morbidity and mortality are obviously negatively influenced by the advanced age of many candidates.
Figure 22-8. After removal of the diverticulum, the mucosal and muscular layers are closed with interrupted sutures. The closure may be tested for leak by air insufflation and distal occlusion. (n. = nerve.)