Zenker diverticulum is a term describing the herniation of the mucosal and submucosal layers of the pharynx through the cricopharyngeus muscle at the pharyngoesophageal junction. It is most likely as a result of increased intraluminal pressure and tissue degeneration. It often appears in the elderly, usually over 70 years of age. Dysphagia, odynophagia, and regurgitation are seen in the majority of patients. The diagnosis is made with a barium swallow study, while surgery is the mainstay of treatment.
The majority of patients with Zenker diverticulum complain of symptoms that can last from weeks, months to even years, the most common being dysphagia, odynophagia, and food regurgitation occurring hours after meals . Halitosis, chronic cough,and aspiration pneumonitis, as well as hoarseness and a sensation of a lump in the throat, have been described by many patients, especially in the case of a large diverticulum . In some patients, on the other hand, the disease may be asymptomatic and the diagnosis can be made incidentally.
To make an initial diagnosis, a high dose of clinical suspicion is necessary. Supported by typical findings in elderly patients, barium swallow studies should be conducted. This method comprises ingestion of barium that lines the esophageal mucosa and visualization of the esophagus and the GI tract is performed under videofluoroscopy. This method is very effective in revealing the exact location as well as the size of the diverticulum . More importantly, this procedure can reveal other accompanying findings, such as reflux esophagitis and hiatus hernia . If barium swallow studies are guided by videofluoroscopy, the lining of the pouch can be examined and a potential carcinoma residing in the diverticulum can be excluded.
Asymptomatic cases do not require therapy, but in patients who report symptoms that persist for a prolonged period of time, surgical therapy is the method of choice. The approach depends on the size, exact location, and presence of accompanying comorbidities. There are two main forms of surgical treatment, open surgery, and endoscopy. However, endoscopy is less invasive and has shown to carry lower complication rates, which is why it is increasingly being chosen as the main form of therapy . Cricopharyngeal myotomy, either open or endoscopic, is most commonly performed. Various other procedures, including endoscopic staple diverticulectomy, diverticular inversion,and other procedures can be performed with good results. The choice of the most optimal approach depends on the surgeon.
Various complications have been described to occur with Zenker diverticulum including hemorrhage, bleeding, perforation, vocal cord paralysis and diverticulitis . Surgical management of elderly patients, on the other hand, can be risky, since many patients usually have one or more comorbidities . Despite both preoperative and postoperative complications that may also occur, the introduction of newer surgical techniques into daily practice, mainly endoscopy, have reduced complication rates significantly and can be safely performed in all patient groups .
This pouch is formed by protrusion of pharyngeal mucosa and submucosa through the Killian's triangle, which is composed of oblique muscle fibers from the inferior constrictor muscle and transverse fibers of the cricopharyngeus muscle. Increased intraluminal pressures , as a result of upper esophageal sphincter dysfunction and various other conditions, together with degenerative changes of the structures in the Killian's triangle are hypothesized to be the main factors of Zenker diverticulum formation. This diverticulum belongs to the group of "false" diverticula, as only the mucosal and the submucosal layers form its wall.
Studies in the United States show prevalence rates between 0.01-0.1%, while incidence rates in high-risk countries is 2 per 100,000 individuals every year, indicating that it is rarely encountered in medical practice . However, many patients remain undiagnosed, primarily because Zenker diverticulum may often have an asymptomatic course. For some reason, patient populations with conditions like hiatal hernia and gastroesophageal reflux disease (GERD) have been reported to have higher incidence rates of Zenker diverticulum . Epidemiological studies have also established a certain geographical predilection toward the region of Northern Europe, with a significantly higher rate of occurrence . A slight predilection toward male gender is seen across various studies (1.5:1), but more importantly, advanced age is shown to be a significant factor. The vast majority of patients are elderly, often over 70 years of age and very few cases have been documented in patients under 40 years of age.
The pathogenesis of Zenker diverticulum starts with elevation in the pressure inside the lumen of the upper gastrointestinal tract, mainly because of defective function of the upper esophageal sphincter , but other conditions, such as GERD , have also been shown to be potential triggers. Increased pressure alone is not considered to be sufficient to cause herniation and formation of this pouch. Anatomical abnormalities of the cricopharyngeus muscle, including incomplete relaxation, loss of elasticity and atrophy, as well as progressive degeneration and replacement of myocytes by fibrous and adipose tissue has been suggested by many studies as a cause, which is supported by the fact that the majority of patients in whom this condition develops are elderly. These events lead to formation and protrusion of the pouch, consisting of mucosal and submucosal layers, through the Killian's triangle and serves as a favorable site for food storage, thus giving the characteristic symptoms.
Preventive measures for Zenker diverticulum currently do not exist, although the mechanisms which lead to its occurrence have been identified.
Zenker diverticulum is a sac-like pouch that herniates between fibers of the pharyngeal muscles at the pharyngoesophageal junction and includes mucosal and submucosal tissue layers. This condition was first described more than 250 years ago , but its exact pathological features were elucidated and confirmed by Zenker and his associates in the 1870s . It is believed that increased intraluminal pressure, most likely due to impaired upper esophageal sphincter function , is the primary factor in the pathogenesis. Additionally, the site through which the Zenker diverticulum is formed, the Killian triangle, consisting of fibers of the thyropharyngeus and cricopharyngeus muscles, is reported to degenerate over time, thus presenting as a favorable site for the development of this pouch-like formation . Prevalence rates estimate Zenker diverticulum to occur in approximately 2 per 100,000 individuals every year. The northern Europe region, for some reason, exhibits significantly higher incidence rates of this condition . Advanced age is determined to be a significant factor, as the majority of patients are more than 70 years of age. The most common symptoms may last from weeks to even years and are dysphagia, odynophagia, and food regurgitation. Other symptoms like cough, halitosis, and aspiration have also been reported in various percentages . This condition may also be asymptomatic, and prevalence rates are thought to be higher in reality due to many undiagnosed and unreported cases. Although the diagnosis cannot be made solely on clinical grounds, a strong suspicion toward Zenker diverticulum in elderly patients with such symptoms can be made, after which appropriate diagnostic procedures can be used. Barium swallow studies (usually guided by videofluoroscopy) have demonstrated to be effective in identifying the diverticulum and is considered to be the diagnostic method of choice. Treatment principles invariably include surgical repair, either open surgery or laparoscopy. Much debate regarding the indications for surgery exists, as it may cause more harm than benefit given the fact that it is performed in elderly patients with other comorbidities. Due to a risk of numerous complications associated with the diverticulum, such as diverticulitis, ulceration, bleeding, vocal cord paralysis and in rare cases, undetected malignancy in the diverticulum, surgical treatment is advocated in all patients . This condition does not pose a significant risk for the patient, but symptoms can be chronic and can severely affect the quality of life. For these reasons, an early diagnosis and appropriate therapy is important for long-term care.
Zenker diverticulum is a pouch that develops at the junction of the throat and the esophagus, most likely as a result of increased pressures inside the upper gastrointestinal tract and anatomical anomalies at the site of its protrusion into the neck. It is hypothesized that the activity of the upper esophageal sphincter, the anatomical structure that mediates passage of food from the oral cavity to the stomach, is impaired, thus creating increased tension within the esophageal walls. Additionally, the site where the protrusion occurs is thought to be affected by tissue degeneration and atrophy, which is why perhaps the majority of patients in whom this diagnosis is made are over 70 years old. Zenker diverticulum is a rare condition, affecting about 0.01-0.1% in the United States while incidence rates are approximately 2 per 100,000 individuals in the world population every year. For unknown reasons, the incidence in Northern Europe is significantly higher. Apart from mechanical factors and aging, patients with conditions like hiatal hernia and gastroesophageal reflux disease have shown to have significantly increased risks of developing Zenker diverticulum. Patients most report symptoms that last for weeks, months and sometimes even years, and include difficult and painful swallowing, bad breath, as well as regurgitation of food. To confirm the diagnosis, a specific diagnostic procedure called barium swallow test, an X-ray imaging of the esophagus and the upper part of the gut after ingestion of barium is performed. The barium sticks to the esophageal mucosa and can efficiently determine the presence of a diverticulum, as well as other conditions such as hiatal hernia. Once the diagnosis is confirmed, treatment can be initiated and usually comprises of surgery. Open surgery was recommended until endoscopic surgery was introduced and subsequently established to be less invasive and less dangerous, especially if patients have one or more comorbidities, which can be the case in this condition as most patients are elderly. Although this condition may cause complications and operation can cause undesired events as well, treatment is generally recommended, especially in patients who report chronic symptoms.