Esophageal Diverticula

Etiology

While the etiology of esophageal diverticula is not fully known, there is a thought that the diverticula form when there is an increase in luminal pressure, and the pressure pushes outward where there is a weakness in the lumen resulting in an outpouching of the mucosa.[2] It can also be seen as a complication from an esophageal motility disorder such as achalasia.

Epidemiology

Esophageal diverticula occur in less than 1% of the population[2]. They are found in approximately 1% to 3% of those presenting with dysphagia. It can occur in all ages but are typically diagnosed in the elderly. They are usually found more in men than in women.

Pathophysiology

There are different ways that esophageal diverticulum can form. Pulsion diverticula occur when there is an inadequate relaxation of either the upper or lower esophageal sphincter resulting in increased intraluminal pressure and subsequent herniation of the esophageal wall at an area of weakness.[1] These usually occur in achalasia and esophageal dysmotility. Traction diverticula occur when there is an external force on the esophageal wall that pulls on the esophageal wall creating a diverticulum. These usually occur in the middle esophagus due to mediastinal inflammation adhering to the esophagus and retracting it to form the defect. Traction diverticula may be seen in patients with tuberculosis, but in the USA, histoplasmosis is the most common cause.

In the lower esophagus, epiphrenic diverticulum is also known as pulsion diverticulum. The wall of the esophagus is pushed as a result of incoordination between the lower esophageal sphincter and the lower esophagus.

Zenker diverticulum occurs in between the muscle fibers where there is a weakness. A bulge will form and over time, the intraluminal pressure will enlarge the diverticulum. It does not appear that the cause of Zenker diverticulum is associated with incoordination between pharyngeal contraction and relaxation of the upper sphincter.

To date, there is no evidence that reflux plays a role in the etiology of esophageal diverticulum

Histopathology

The esophagus is composed of 4 layers; from the lumen going outward, they are the mucosa, submucosa, muscularis, and adventitia. True diverticula consist of all esophageal wall layers within the protrusion.[4] With false diverticula, only the mucosa and submucosa layers will be seen. Squamous cell carcinoma can rarely be found in conjunction with esophageal diverticula.

History and Physical

Symptomatic patients typically present with dysphagia.[4] Other presenting symptoms include regurgitation of intact food, aspiration pneumonia, weight loss, halitosis, and cough due to food being retained within the diverticulum. Patients rarely present with a mass in the neck. However, most patients are asymptomatic and may never be diagnosed with the diverticulum until they become symptomatic.

Besides dysphagia, other symptoms may include hypersalivation, cough, a sensation of food sticking at the back of the throat and regurgitation of food.

Evaluation

Most patients are diagnosed by barium esophagogram.[4] This study helps give information regarding location and size besides the diagnosis. Esophagogastroduodenoscopy can be done to confirm the diagnosis and is sometimes the initial diagnostic test. They can also be found incidentally on video swallow studies.

Endoscopy can be dangerous as there is a real risk of esophageal perforation.

Manometry studies are done to rule out motor disorders.

Treatment / Management

If patients are asymptomatic, then the diverticula are left intact.[4][6] This is usually the case in mid-esophageal and epiphrenic diverticula.[7] However, for symptomatic patients, there are surgical and endoscopic therapeutic options. This is more often seen in the pharyngeal diverticulum. Therapeutic options include diverticulectomy, diverticulopexy, and diverticular inversion, with or without myotomy, and myotomy alone.[8] Surgical options include open or laparoscopic approach. Most often, patients undergo minimally invasive myotomy and removal of the pouch endoscopically with either a soft or rigid endoscope.[9] If patients are not surgical candidates, then management with diet changes such as eating bland food and drinking water after every bite to help flush any food out of the diverticulum is recommended.(B2)

With Zenker diverticulum, surgery involves resection of the diverticulum and a small cricopharyngeal myotomy to lower sphincter pressure.

Today endoscopic treatments are gaining prominence over surgery. The procedure utilizes a rigid endoscope and dividing the connection between the esophagus and the diverticulum. In addition, a small myotomy is done.

Differential Diagnosis

Differential diagnoses include achalasia, esophageal cancer, esophageal stricture, gastroesophageal reflux, and presbyesophagus.[2] It is important to obtain a good history to help distinguish between these possible diagnoses.

Treatment Planning

Endoscopic myotomy (Dohlman Procedure) demands neck extension; therefore, it would not be an appropriate choice for patients with cervical stenosis who would not tolerate neck extension. The definitive management of symptomatic Zenker diverticulum is the surgical approach. The decision to use either an open or endoscopic transoral approach (rigid endoscope or a flexible endoscope) is made by clinicians based on several factors. The most important factors to be considered are 1. the ability to visualize the ZD and septum endoscopically, 2. patient's body habitus, 3. the ZD pouch feature in relation to the posterior wall, and 4. local expertise. Accordingly, patients with short necks decreased hyomental distance, and/or those patients with obesity are most often managed with an open approach. However, diverticula with less than 2 cm length are usually managed with endoscopic methods.

Transoral (endoscopic) approaches are categorized as minimally-invasive surgery and are associated with shorter procedural times, hospital stays, rapid resumption of oral intake, lower rate of complications. More significantly, in case of recurrence, the access would be easier. Endoscopic approaches are also associated with significantly high rates of symptom recurrence. 

For patients who are considered poor surgical candidates, a flexible endoscopic approach is the procedure of choice. The main advantage of the flexible endoscopic approach is that it can be performed without general anesthesia. On the contrary, general anesthesia is required for open surgical and rigid endoscopic approaches. Hypothetically, a higher recurrence rate and the need for revision with a flexible endoscopy approach are expected.  Bleeding and recurrence are more likely following flexible endoscopic techniques. However, dental injury and vocal fold palsy are expected as rare complications following the rigid endoscopy.[10][11][12]

Prognosis

Prognosis of these patients is dependent on their age and comorbidities as this will determine their surgical candidacy.[13] Risks and benefits need to be weighed. Most patients will have good results as far as immediate resolution of symptoms with surgical treatment with varied recurrence rates. However, surgical complications can be serious and need to be considered when deciding on whether to pursue surgical treatment and which surgical approach to pursue.

Complications

Esophageal diverticula complications are rare but include esophageal obstruction, perforation, and squamous cell carcinoma.[13]