Surgical Management of Mid- and Distal Esophageal Diverticula

Pathophysiology

Despite advances in manometric evaluation, the pathogenesis of an epiphrenic diverticulum has not been fully elucidated. It is generally accepted that this type of diverticulum is almost always secondary to an underlying esophageal motility disorder. Named motility disorders associated with these diverticula include achalasia, diffuse esophageal spasm, nutcracker esophagus, and hypertensive lower esophageal sphincter (LES), with the most common being achalasia followed by diffuse esophageal spasm. One theory suggests that the presence of dysmotility causes an uncoordinated contraction between the distal esophagus and lower esophageal sphincter leading to increased intraluminal pressure and subsequent herniation through a weakened area of the esophagus. Another study identified that esophageal diverticulum is associated with areas of low peristaltic pressure amplitude, bizarre peristaltic wave forms, and hypertensive peristaltic pressures. Other reported etiologies such as a distal stricture, prior fundoplication, and hiatal hernia all act to create the same outflow pressure dynamics as a motility disorder.

Symptoms and Diagnosis

Epiphrenic diverticula present either asymptomatically when they are incidentally identified on a radiographic study or with symptoms due to the underlying motility disorder and associated outpouching. Symptomatic patients most commonly present with dysphagia (90%), regurgitation of undigested food (80%), and repetitive episodes of aspiration (30%). However, there is a range of symptomatic patients, some who have minimal or only intermittent symptoms of dysphagia, and others who have incapacitating and at times life-threatening symptoms particularly from regurgitation of undigested food that is often precipitated by position and is most often at night. Chest pain, pyrosis/heartburn, and weight loss are also commonly reported.

It is often difficult to determine whether the symptoms originate with the diverticulum itself or the underlying motility disorder. In one study comparing symptoms in different size diverticula in patients with and without a motility disorder, increasing diverticula size, particularly those 5 cm or greater, was more likely to produce symptoms irrespective of the presence of a motility disorder. This suggests that symptoms are more likely derived from the motility disorder early in the disease process. However, with disease progression and increasing anatomic distortion, the diverticulum begins to drive symptoms.

The diagnosis of an epiphrenic diverticulum is initially confirmed by barium esophagram in which one or more diverticula are identified. However, for patients being considered for surgical treatment, the barium esophagram is only the start of a comprehensive evaluation. All patients should undergo a thorough history and physical examination to document comorbidities and guarantee surgical fitness. This is followed by three main studies:

• Barium swallow

  • Allows measurement of length and size of diverticulum

  • Orients diverticulum (right/left)

  • Identifies other pathology such as hiatal hernia, stricture

  • Provides information about esophageal motility

• Esophagogastroduodenoscopy (EGD)

  • Defines anatomy of diverticulum, including precise location relative to the gastroesophageal junction (GEJ) ( Fig. 12.4 )

    

  • Assesses for concomitant pathology such as ulceration or malignancy

  • Used to treat bleeding, place manometry catheter, feeding tube

• High-resolution manometry

  • Defines underlying motility disorder

  • May need to be placed endoscopically or under fluoroscopy

  • Potentially guides length of myotomy

In addition to the primary studies, there are several additional studies that may provide additional information preoperatively and during long-term follow-up. A timed barium swallow has been used to manage patients treated for achalasia. This standardized test when performed prior to surgery and then during follow-up provides a simple and objective method of esophageal emptying, since symptoms are unreliable in this setting. A computed tomography scan of the chest can be helpful in determining the true proximal extent of the diverticulum. When the superior edge of the diverticulum is beyond the inferior pulmonary veins, it may be very difficult to access laparoscopically and suggests the need for the addition of a thoracoscopic procedure to completely resect the diverticulum. Lastly, patients with suspected symptoms of gastroesophageal reflux disease (GERD) may undergo pH testing as necessary.

Treatment

The decision to offer treatment to a patient with an epiphrenic diverticulum is based on the patient's symptoms and severity of those symptoms. Patients who are asymptomatic or minimally symptomatic may forgo any treatment, but whether they require ongoing follow-up is controversial. Two long-term follow-up studies from the Mayo Clinic provide conflicting data. Debas et al. in 1980 detailed the outcomes of 37 patients undergoing nonoperative treatment. In this group of patients, seven remained without symptoms and were followed, two underwent surgery elsewhere, and six were treated with esophageal dilation with resolution of symptoms. In the remaining 22, 15 had no details, but 4 of the remaining 7 experienced an aspiration event with one death, 2 patients became malnourished, and 1 patient developed an esophageal carcinoma. This suggests that continued follow-up is necessary because of the development of worsening symptoms. Comparatively, Benacci et al. in 1993 documented outcomes of 71 patients without symptoms or minimal symptoms. Of 47 patients who were asymptomatic, 27 were lost to follow-up, and 20 patients were followed for a median of 4 years (range 1–17) and remained stable. Of 24 patients with mild symptoms, 9 were lost to follow-up, and 15 were followed a median of 11 years (range 1–25 years) with either EGD or barium swallow with stable minimal symptoms. Although many patients remained stable, the outcomes of many were lost in follow-up. Because the symptoms that develop can be devastating, it seems reasonable to follow these patients to ensure that progressive symptoms do not develop given the rarity of this disease and the unpredictable development of symptoms.

The indication for surgical treatment is symptoms attributable to the diverticulum or motility disorder. Surgical evaluation is mandatory if a patient developed incapacitating symptoms or respiratory compromise from aspiration of the esophageal contents. Regardless of the surgical approach, there are a number of surgical principles that have been articulated surrounding the treatment of these diverticula. These key steps include:

• Delineation of the entire diverticulum at the mucosal level

• Definition of the “neck” of the diverticulum

• Resection of the diverticulum

• Closure of the overlying muscle with or without buttress

• Distal myotomy with or without partial fundoplication

Surgical Approaches and Results

At present, there are a variety of approaches used to surgically treat an epiphrenic diverticulum including transthoracic, video-assisted thoracic surgery (VATS), laparoscopic, combined VATS-laparoscopic, and reports of endoscopic approaches have recently emerged.