What is Zenker's Diverticulum?
Zenker's diverticulum is an acquired false pulsion diverticulum characterized by herniation of the mucosal and submucosal layers through Killian's dehiscence (a natural weakness between the inferior pharyngeal constrictor and cricopharyngeus muscle) at the posterior pharyngoesophageal junction. 1, 2
Anatomic and Pathophysiologic Features
Location: The diverticulum occurs dorsally at the pharyngoesophageal wall, specifically through Killian's dehiscence, which is the triangular area of weakness between the thyropharyngeus and cricopharyngeus muscles 1, 2
Type of diverticulum: This is a false (pseudodiverticulum) and pulsion diverticulum, meaning it contains only mucosal and submucosal layers without the muscular layer, and is pushed outward by increased intraluminal pressure 1, 2
Underlying mechanism: The pathophysiology involves decreased compliance and altered function of the cricopharyngeus muscle (upper esophageal sphincter), which fails to open completely during swallowing 2. This creates elevated intrabolus pressure in the hypopharynx, forcing the mucosa to herniate through the area of anatomic weakness 2
Epidemiology and Patient Demographics
Prevalence: Zenker's diverticulum is the most common type of esophageal diverticula, with a reported prevalence ranging from 0.01% to 0.11% in the general population 1
Age distribution: This condition typically affects middle-aged and elderly patients, with mean ages in treatment series around 80 years (range 68-91 years) 1, 3
Clinical Presentation
The predominant symptoms include:
Dysphagia: Progressive difficulty swallowing, initially for solids and potentially progressing to liquids 1, 2
Regurgitation: Patients characteristically experience regurgitation of undigested food hours after meals (typically 2-6 hours post-meal) 2
Odynophagia: Painful swallowing may occur 2
Weight loss: Significant weight loss can result from progressive symptoms 2
Aspiration: Risk of aspiration pneumonia due to regurgitation of diverticulum contents 1
Important Diagnostic Considerations
Not all dysphagia is from the diverticulum: The American College of Radiology emphasizes that the diverticulum may be incidental, and other causes of dysphagia must be excluded 4
Imaging limitations: Standard CT may not visualize Zenker's diverticulum well 5. The appropriate diagnostic study is a biphasic esophagram (barium swallow), which can detect both structural and functional abnormalities 5
Associated conditions: The American Gastroenterological Association notes that Zenker's diverticulum may occur with or without a cricopharyngeal bar, and upper esophageal sphincter dysfunction should be evaluated 4, 6
Treatment Principles
Treatment is recommended for symptomatic patients and must include myotomy of the cricopharyngeal muscle, as this addresses the underlying pathophysiology of upper esophageal sphincter dysfunction. 1, 7
The American Gastroenterological Association recommends upper esophageal sphincter dilatation for treatment of dysphagia with disordered upper esophageal sphincter opening, cricopharyngeal bar with or without Zenker's diverticulum 4, 6. Modern management has evolved from open surgery to minimally invasive endoscopic approaches, with Zenker's peroral endoscopic myotomy (Z-POEM) achieving clinical success rates of 85.5-93% and representing the latest advancement for this predominantly elderly, high-risk patient population 7.