Introduction

Zenker’s type is the most important diverticulum of the esophagus and usually causes symptoms that require surgical treatment. Zenker’s diverticulum (ZD) is an indication for minimally invasive endoscopic treatment, which is important as an alternative to operative therapy because most patients with ZD are elderly.

Epidemiology

ZD is a false diverticulum first described by Ludlow in 1769.¹ X-ray studies have shown its incidence to be around 0.1% of upper gastrointestinal (GI) barium studies.² Of patients, 80% are older than 60 years.³ ZD is more frequent in men than in women.³ The occurrence in children is rare,⁴ and no differences have been mentioned concerning race or geographic areas.

Pathogenesis

ZD develops as a result of the cooccurrence of weak points in the posterior wall of the hypopharynx and a lack of coordination between the pharyngeal constrictor and the cricopharyngeal muscles.⁵ Fibrosis of the cricopharyngeal muscle and the striated muscle of the upper esophagus has been shown more recently as the cause of such incoordination.^6,7 Contraction of the pharyngeal constrictor muscle combined with the absence of relaxation of the cricopharyngeal muscle results in difficult passage of a food bolus and an increase in local pressure, which makes the mucosa and submucosa bulge through the weak sites between the descending fibers of inferior constrictor and transverse cricopharyngeal muscles, which constitute the distalmost part of the inferior constrictor (Fig. 20.1). Some authors believe that the incomplete sphincter opening is more likely than the incoordination to cause dysphagia.⁶ The mucous membrane sac can also pass through or immediately beneath the cricopharyngeal muscle.

Fig. 20.1 Schematic view of hypopharynx. Dots show sites of weakness from which a Zenker’s diverticulum can develop.

Clinical Features

There is a well-established relationship between the anatomic changes and clinical symptoms.⁸ When a ZD is small, the patient has the sensation of having a foreign body in his or her throat. Throat irritation with excessive mucus is also common. As the ZD increases in size, regurgitation of food and mucus begins to occur after meals and when the patient lies down. If the sac is very large and the opening is transverse, the preferential route of food would be into the ZD. Symptoms of obstruction appear in this case, and many patients lose a significant amount of weight. In the second and third phases of the disease, pulmonary complications are common and sometimes repetitive, usually obliging the patient to seek treatment. Difficulty swallowing large food boluses, medication, or devices such as endoscopic capsules can be the earliest indicators for the detection of ZD.⁹

Pathology

The diverticulum arises as a protruding area at the weak points of the muscular structures of the hypopharynx and then increases progressively. The wall of the sac is formed only by the mucosa and submucosa. In contrast to esophageal diverticula, ZD is not a true diverticulum. As a diverticulum, ZD forms a pouch and descends along the left side of the neck; however, it may be present on either side. In advanced phases of the disease, the mucosa may show esophagitis. The incidence of cancer seems to be higher in patients with ZD than in patients without this disease.^10,11 ZD is usually found in association with some other esophageal disease, such as hiatal hernia, gastroesophageal reflux, esophageal membranes in 50% of cases, achalasia, and polyps.^12,13

Differential Diagnosis

Radiography is very useful when the patient experiences some difficulty in swallowing solid medication, such as a pill, and it is important in advanced phases of ZD. If the sac is not small, the diagnosis is easily established in the anteroposterior projection (Fig. 20.2).¹⁴ The sac lies in the midline and extends to the left. However, in the case of a small and nonretentive ZD, the lateral projection is important (Fig. 20.3). When aspiration of a bolus is suspected, an x-ray study without barium is needed. In such a case, iodine contrast material should be used to avoid complications secondary to aspiration of barium into the lung. Sometimes it is necessary to clear the ZD lumen from retained foods to avoid filling defects that may look like mucosal lesions on imaging.

Fig. 20.2 Lateral x-ray study of esophagus showing a Zenker’s diverticulum.

Fig. 20.3 Frontal upper gastrointestinal barium study of esophagus showing a Zenker’s diverticulum (ZD). The contrast material remained in the ZD.

Endoscopy is the alternative diagnostic test. For many years, endoscopy was not recommended; however, it is a very important means of diagnosis and treatment. Even when the diagnosis of ZD has been established, endoscopy should be performed because alterations in the mucosa can occur, and a biopsy is essential (Fig. 20.4). The incidence of cancer is higher in ZD mucosa than in normal esophageal mucosa. In early phases of the disease, when ZD cannot yet be detected, the difficulty found in inserting the endoscope into the esophagus is the most common basis for the suspicion of ZD. Because endoscopy is the first option of most physicians, when a patient presents with upper GI tract symptoms, the possibility of a ZD must be considered in case of such difficulty.

Fig. 20.4 Ulcerated lesion in a Zenker’s diverticulum.

The endoscopy procedure is not dangerous in experienced hands, and insertion of the endoscope into the esophageal lumen is usually achieved often with the help of a flexible accessory used as a guide (Fig. 20.5