Esophageal diverticula are unusual but interesting abnormalities that can develop in any part of the esophagus. Most commonly they are found in the cervical esophagus, and in this location they are known as Zenker's diverticula. Esophageal diverticula also may be found in the midesophageal area near the pulmonary hilum and in the epiphrenic region in the distal esophagus.

There are two types of esophageal diverticula–pulsion and traction. Each has a distinct etiology. The pulsion type is the most common form in the United States. A pulsion diverticulum develops as a consequence of a motility abnormality in the esophagus distal to the site of the diverticulum.¹ The most common pulsion diverticulum is the Zenker's variety, and it occurs secondary to repetitive pharyngeal pressure on boluses of food that are delayed by a dysfunctional cricopharyngeus muscle.² Over time, this pressure causes a herniation of the esophageal mucosa through a weak point, called Killian's dehiscence. This point is located superior to the cricopharyngeus muscle at its junction with the inferior constrictor muscle. Pulsion diverticula are not composed of the entire wall of the esophagus and therefore are considered false diverticula (Fig. 25-1). Radiographically, they tend to have a wide neck and rounded contour, and typically they retain contrast material on a barium swallow (Fig. 25-2).

Traction diverticula, on the other hand, are caused by granulomatous inflammation of mediastinal lymph nodes. The inflamed nodes attach to the esophagus. With subsequent contraction, the nodes pull on the esophagus, creating a conical outpouching. Traction diverticula are considered true diverticula because the entire wall of the esophagus is involved in the defect. In contrast to pulsion diverticula, traction diverticula tend to have a pointed tip that empties well on barium swallow (Fig. 25-3). Traction diverticula are found most commonly in areas where tuberculosis or histoplasmosis is endemic. The prevalence of all types of diverticula increases with age.

Symptoms associated with pulsion diverticula are often initially related to the underlying motility abnormality, but as the size of the diverticulum increases, the symptoms also may become more attributable to the pouch itself.³ Thus, while dysphagia often is the primary symptom initially, when the pouch becomes large, regurgitation may be the more prominent symptom. At first glance, the symptoms appear to mimic gastroesophageal reflux, and many patients are treated empirically for gastroesophageal reflux disease (GERD) (Fig. 25-4). However, careful questioning will elicit the important information that the regurgitated material tastes bland, not bitter, in which case the substance is food and fluid that never made it to the stomach rather than material refluxing from the stomach. Other symptoms attributable to a diverticulum are halitosis, cough, and aspiration of debris retained within the pouch. The larger and more proximal the pouch, the more troublesome these symptoms may be for patients.

Surgery is the only effective therapy for esophageal diverticula.⁴ Dilation of the cricopharyngeus muscle has been attempted in patients with Zenker's diverticulum with limited success. Even if the dilation is successful, it only addresses the dysphagia component of the patient's symptoms. The surgical plan for patients with a pulsion diverticulum includes myotomy of the dysfunctional esophageal muscle adjacent and distal to the diverticulum and either excision or suspension of the diverticulum based on its size and location.^5,6 Failure to divide the dysfunctional muscle leads to a high rate of recurrence and increases the risk of a leak from the suture or staple line if the diverticulum has been excised.^3,4 For patients with a symptomatic traction diverticulum, only excision of the diverticulum is necessary, but the fibrotic nodes that caused the diverticulum can make the dissection tedious.

Approaches to both pulsion and traction diverticula include the traditional open techniques and more recent transoral, laparoscopic, and thoracoscopic minimally invasive options. Given the absence of effective nonsurgical therapy and the relative safety of most of these procedures, symptomatic patients with an esophageal diverticulum should be considered for surgical therapy regardless of age.

PREOPERATIVE ASSESSMENT

The physical examination of patients with an esophageal diverticulum generally is unrevealing, even when a large Zenker's diverticulum is present. However, if a transoral approach for correction of a Zenker's diverticulum is being considered, it is important to assess the ability of the patient to adequately open the mouth and extend the neck.⁶

The best way to visualize an esophageal diverticulum is with a barium swallow,⁴ although our preference is a video swallow esophagogram because in addition to showing the size and location of the diverticulum, it provides information about the efficacy of bolus transport by the esophageal body. The barium study also should be used to assess for hiatal hernia or other potential abnormalities associated with the presence of GERD. Upper endoscopy is useful both to measure the size of the diverticulum and to evaluate the esophageal mucosa for any abnormalities, particularly in elderly patients, in whom it is essential to rule out malignancy. Esophageal manometry is important in patients with a mid- or distal esophageal diverticula to evaluate for an underlying motility abnormality, but in patients with a Zenker's diverticulum, the cause is dysfunction of the cricopharyngeus muscle, often from scarring, fibrosis, or neurologic abnormalities such as a stroke. Motility abnormalities are not always present. This suggests that standard motility studies lack sensitivity for the evaluation of cricopharyngeal dysfunction.

In younger patients with a Zenker's diverticulum, the association with GERD is high, and there is often an absence of any other predisposing factors. Thus one has to question the potential association of proximal reflux and dysfunction of the cricopharyngeus muscle in the development of Zenker's diverticulum. Certainly, reflux should be considered and further evaluated if present in an otherwise healthy patient under age 50 who presents with a Zenker's diverticulum. If an esophageal motility study is planned, it is usually necessary to pass the motility catheter using endoscopic guidance because otherwise the catheter may coil in the diverticulum. Motility abnormalities that may be recognized with a Zenker's diverticulum include evidence of outflow obstruction such as increased bolus pressure in the pharyngeal contraction wave and incomplete relaxation of the cricopharyngeus with a swallow.² The most common motility abnormality in patients with epiphrenic diverticula is achalasia, but others include hypertensive lower esophageal sphincter, nutcracker esophagus, and diffuse esophageal spasm.³

OPERATIVE TECHNIQUE

Transcervical Cricopharyngeal Myotomy and Diverticulectomy or Suspension

The traditional approach for repair of a Zenker's diverticulum is transcervical, with the patient positioned supine and the neck extended. An incision is made in the left neck along the anterior border of the sternocleidomastoid muscle. The sternocleidomastoid muscle and carotid sheath are retracted laterally. The omohyoid, sternothyroid, and sternohyoid muscles are divided to facilitate exposure of the entire cervical esophagus. The Zenker's diverticulum will be located posterior to the cricoid cartilage. The diverticulum is sheathed in multiple layers of fibrous tissue that must be teased apart to permit exposure of the base of the diverticulum.

Once exposed, a longitudinal myotomy on the posterolateral aspect of the cervical esophagus is started just inferior to the base of the diverticulum. It should extend inferiorly to the thoracic inlet, and then it is carried superiorly through the muscular ring of the cricopharyngeus at the base of the diverticulum. Typically, the muscle in the area of the base of the diverticulum is quite thick and fibrotic. Once released, the diverticulum should be clearly visualized. To ensure that all the dysfunctional fibers are divided, we also incise the lower fibers of the inferior pharyngeal constrictor superiorly from the base of the diverticulum for 1–2 cm. In addition, the edges of the divided muscle should be bluntly dissected to widely splay open the mucosa and permit identification and division of any residual circular muscle fibers.

Next, the diverticulum is either suspended or excised. Diverticula that are 2 cm or less in size are easily suspended by tacking the tip of the diverticulum with 3–0 Prolene to the precervical fascia as high up in the neck as necessary to fully upend the pouch. Larger pouches are difficult to fully upend and are best excised using a TA stapler with a 52F bougie in the esophagus to prevent narrowing of the esophageal lumen. The staple line and/or myotomy can be checked for leaks by passing a nasogastric tube into the area and insufflating air to distend the mucosa while the neck incision is filled with saline. This also provides an opportunity to ensure sufficient mucosal distention with no residual bands throughout the area of the myotomy. Before neck closure, it is critical to ensure perfect hemostasis because a hematoma requiring reexploration can develop from even small vessels secondary to coughing or straining as the patient awakens from anesthesia. We leave a small closed suction drain in place and approximate the platysma and skin to complete the operation.

Transoral Endoscopic Stapled Diverticulotomy

A transoral endoscopic approach is another option for treating Zenker's diverticulum. This approach is attractive largely because it eliminates the neck incision but limited because the pouch must be at least 3 cm in length and the patient must be able to extend the neck and open the mouth widely. Inability to extend the neck and open the mouth adequately makes placement of the Storz rigid diverticuloscope difficult to impossible. If the diverticulum is less than 3 cm in length, it will not permit adequate division of the dysfunctional cricopharyngeus muscle, leading to persistent or recurrent symptoms. Patients with evidence of malignancy inside the pouch are also not candidates for transoral stapling technique and instead require excision of the pouch.⁷ Although the procedure is quick and well tolerated, and in suitable patients produces excellent relief of dysphagia and regurgitation symptoms, patients must be warned of the possibility of chipped teeth secondary to the rigid scope insertion. In addition, most patients have significant tongue swelling for a day or two after the procedure.

Before the procedure commences, a 30-mm GIA laparoscopic stapler is modified by cutting off the tip of the stapler with an orthopedic circular saw such that the knife blade and the staple line reach the end of the modified tip. The tip should be smoothed with a rasp or file. The patient is placed under general anesthesia and positioned supine with the neck extended, and the Storz diverticuloscope is inserted carefully under direct visualization and advanced into the esophagus. It is helpful to have a pediatric flexible esophagoscope to facilitate placement of the rigid scope. The goal is to advance the longer anterior blade into the true lumen of the esophagus while the shorter posterior blade is advanced into the diverticulum. Once positioned, the blades of the scope are separated to permit clear visualization of the cricopharyngeus muscle band (Fig. 25-5). Using a laparoscopic needle holder, 3–0 Prolene traction sutures are placed on each side of the cricopharyngeus muscle (Fig. 25-6). With gentle traction on these stitches, the bar is held in position as the modified GIA stapler is inserted and fired (Fig. 25-7). Several applications of the stapler typically are necessary to divide the muscle bridge all the way to the tip of the diverticulum (Fig. 25-8). In this fashion, the cricopharyngeus muscle is divided, and the pouch is incorporated into the esophagus to create a single common cavity. If the diverticulum is less than 3 cm in length, the cricopharyngeus muscle will not be divided adequately, leading to a high rate of symptomatic failure and a significant risk for the development of a recurrent diverticulum. It is important to modify the stapler to minimize the amount of residual pouch with the transoral approach because even a 1-cm remnant can lead to persistent symptoms of regurgitation. While it is nearly impossible to completely eliminate the pouch, in our experience, patients with less than 4–5 mm of residual pouch remain asymptomatic.

Laparoscopic, Transabdominal, or Transthoracic Esophageal Myotomy; Diverticulectomy; and Partial Fundoplication (Triple Treat)

Epiphrenic diverticula can be treated via a transabdominal or transthoracic approach and either as an open or minimally invasive procedure depending on the size and location of the diverticulum. If the diverticulum is located near the hiatus, a laparoscopic diverticulectomy with esophageal myotomy and partial fundoplication is readily accomplished, but it is important to recognize that many diverticula are more proximal than they appear radiographically, and only those very close to the gastroesophageal junction (GEJ) are amenable to a transabdominal or laparoscopic approach (Fig. 25-9). Most epiphrenic diverticula are located 5–10 cm proximal to the GEJ, and for these patients, a transthoracic approach is optimal. The approach is made via left thoracotomy in the seventh intercostal space. After incision of the mediastinal pleura and identification of the esophagus, the diverticulum can be dissected out and excised. Regardless of approach, once the diverticulum is identified, we prefer to excise it while a 52F bougie is in the esophagus to avoid narrowing the lumen. Subsequently, we close the muscle over the staple line with interrupted 3–0 silk sutures (Fig. 25-10) and perform the myotomy on the opposite side of the esophagus. Care is taken to avoid injuring the vagus nerves as the myotomy is carried down for 2–3 cm onto the anterior wall of the stomach along the greater curve side if possible (Fig. 25-11). Typically, a Dor partial fundoplication is performed (Fig. 25-12), but if there is a hiatal hernia, then crural closure with a Belsey or Toupet partial fundoplication is our standard procedure. Diverticula underneath the aortic arch are difficult to excise from the left chest and are better visualized from the right. In this setting, we prefer a two-stage approach. First, we perform a laparoscopic myotomy and partial fundoplication. In 6 weeks we bring the patient back to the OR for a thoracoscopic diverticulectomy and long esophageal myotomy from the right side.

The objectives of the procedure are identical regardless of the approach and include division of the dysfunctional esophageal muscle distal and adjacent to the diverticulum, excision of the diverticulum, and partial fundoplication to protect the esophagus from gastroesophageal reflux.^1,8 A myotomy that ends at the GEJ is associated with a higher incidence of persistent or recurrent dysphagia than a myotomy that extends 2–3 cm onto the gastric side of the junction.^1,8,9 In our opinion, the best location for the myotomy is along the left lateral aspect of the esophagus with continuation down across the angle of His at the greater curvature side of the stomach. Further, it is clear that the addition of a partial fundoplication reduces esophageal acid exposure after myotomy,¹⁰ and therefore, a partial fundoplication is added to the myotomy in all patients. If the etiology of the diverticulum is traction secondary to mediastinal adenopathy, a myotomy is not needed, and the treatment consists of separation of the esophagus from the culprit nodes (often difficult secondary to intense inflammation, fibrosis, and/or calcification) and excision of the diverticulum. This is best accomplished in most patients via the right chest either as an open or thoracoscopic procedure, and it may be helpful to place pleura or intercostal muscle between the esophageal repair and any residual mediastinal nodes to prevent leakage or recurrence.

POSTOPERATIVE CARE

Patients are kept at nothing by mouth after the procedure until the following day or 24–48 hours longer if the diverticulum has been excised. We typically obtain a Gastrografin esophagogram before starting oral feeds both to document the integrity of the myotomy with or without a staple line and to verify that the patient is able to swallow without aspiration, particularly in a patient who has undergone surgery for a Zenker's diverticulum.

COMPLICATIONS AND RESULTS

Major morbidity is uncommon, but potential complications include a leak from the myotomy or suture line if the diverticulum has been excised, mediastinitis, fistula formation, hoarseness from vocal cord paralysis, incomplete myotomy, luminal stenosis, and wound infection. Long-term complications include recurrence and development of GERD. The likelihood of a recurrent diverticulum is reduced when a myotomy is performed compared with diverticulectomy alone.^3,4 A good or excellent outcome is reported by most patients.

SUMMARY

Esophageal diverticula are uncommon but interesting esophageal abnormalities. In most circumstances, they develop as a consequence of an underlying esophageal motility disorder, although in some patients they occur secondary to mediastinal lymphadenopathy as a consequence of traction rather than pulsion. All symptomatic patients should be considered surgical candidates because there is no effective medical therapy. Surgical treatment for a pulsion diverticulum involves alleviating the outflow obstruction by esophageal myotomy coupled with diverticulectomy or diverticulopexy. An antireflux procedure is added to the myotomy for patients with an epiphrenic diverticulum. In addition to the traditional open approaches, new minimally invasive approaches are applicable in some patients and may reduce procedure-related morbidity and hasten recovery. Careful patient evaluation and technical precision during the procedure will ensure excellent results.

CASE HISTORY

An 85-year-old woman was referred for evaluation of a 5-year history of dysphagia, primarily for solid food and pills and occasionally for liquids when she drank too quickly. She also noticed a frequent gurgling sensation in the neck and experienced regurgitation of undigested food particles, particularly at night when lying down. She endured severe heartburn symptoms for 20 years that were self-treated with over-the-counter medications but recently was placed on Prilosec with excellent relief of symptoms.

On physical examination, her neck was supple with good extension, and she was able to open her mouth widely. She had a barium swallow study that revealed a several-centimeter Zenker's diverticulum and a sliding hiatal hernia. She underwent an upper endoscopy, which demonstrated an approximately 3-cm Zenker's pouch, a sliding hiatal hernia, and a columnar-lined distal esophagus with intestinal metaplasia on biopsy. She was offered surgical therapy for her Zenker's diverticulum. The option of open versus transoral endoscopic approach was discussed, and it was thought that she would be a good candidate for the transoral technique.

Under general anesthesia, she was positioned with the neck extended. A Storz diverticuloscope was introduced transorally and advanced carefully into the esophagus. The pouch was exposed but was determined to be of insufficient size to permit complete division of the cricopharyngeus muscle. Therefore, the diverticuloscope was withdrawn, and the patient was repositioned for an open transcervical approach. Open cricopharyngeal myotomy and suspension of the diverticulum were carried out successfully. The patient had an uncomplicated postoperative hospital course and on discharge noted a significant improvement in swallowing. Her A swallow study done 6 weeks postoperatively revealed a transitory filling of the neck of the suspended diverticulum with no delay in the passage of contrast medium through the cricopharyngeal region.

EDITOR'S COMMENT

When suspending a Zenker's diverticulum, one must be cautious not to directly suture it to the prevertebral fascia, as this can result in osteomyelitis. Occasionally, a relatively small epiphrenic diverticulum can be treated by laparoscopic Heller myotomy and Dor fundoplication without diverticulectomy.

–RB

REFERENCES