Zenker's Diverticulum

Zenker's Diverticulum
Other Names	Pharyngeal Pouch
Barium esophagram with contrast filling a Zenker's Diverticulum
Identifiers
ICD-9	530.6
ICD-10	K22.5
Outside Resources
Radiopaedia	Zenker Diverticulum

Overview

Zenker's diverticulum (also known as pharyngeal pouch or hypopharyngeal diverticulum) is a pulsion diverticulum that herniates through Killian's dehiscence, an area of muscular weakness in the posterior pharyngeal wall between the oblique fibers of the inferior pharyngeal constrictor and the horizontal fibers of the cricopharyngeus muscle. It is the most common type of pharyngoesophageal diverticulum, accounting for approximately 70-80% of cases.

Zenker's diverticulum predominantly affects elderly individuals (>70 years) with a male predominance. A large population-based Finnish study found the annual incidence to be 2.9 per 100,000 person-years, with men having a higher incidence (3.7/100,000) compared to women (2.3/100,000). The prevalence ranges from 0.01% to 0.11% of the population. The condition presents with progressive dysphagia, regurgitation of undigested food, halitosis, and aspiration. Without treatment, symptoms typically worsen over time due to progressive enlargement of the diverticulum.

History

Friedrich Albert von Zenker (1825-1898), a German pathologist, provided the first comprehensive description of this condition in 1877, along with Hugo Wilhelm von Ziemssen. Zenker systematically described the clinical presentation, anatomical location, and pathological features of the pharyngeal pouch, establishing it as a distinct clinical entity.

Gustav Killian subsequently characterized the anatomical weakness (Killian's dehiscence) through which the diverticulum herniates in 1908. Surgical treatment evolved from external open approaches in the early 20th century to endoscopic techniques introduced in the 1960s and refined in subsequent decades.

Pathophysiology

Relevant Anatomy

Zenker's diverticulum occurs as a result of a herniation of the pharyngeal mucosa through Killian's dehiscence (also known as Killian's triangle). This triangular area of weakness is formed by the oblique fibers of the inferior pharyngeal constrictor (thyropharyngeus), which attach anteriorly to the oblique lamina of the thyroid cartilage and posteriorly to the median raphe, and the transverse fibers of the cricopharyngeus, which attach to the cricoid cartilage anteriorly and wind around the pharynx with no posterior attachment.

This area is bounded superiorly by the thyropharyngeus, inferiorly by the cricopharyngeus, and posteriorly by the median raphe. It is located in the posterior wall of the laryngopharynx, slightly above the origin of the esophagus. While not anatomically evident in every individual, it occurs more commonly in males and the dimensions correlate with individual anthropometric parameters.

Related anatomical areas of weakness include:

• Killian-Jamieson space: Anterolateral, BELOW cricopharyngeus (site of Killian-Jamieson Diverticulum)
• Laimer's triangle: Posterior, BELOW cricopharyngeus (site of Laimer's Diverticulum)

Critical adjacent structures:

• Recurrent laryngeal nerve (in tracheoesophageal groove)
• Common carotid artery and internal jugular vein
• Inferior thyroid artery
• Thoracic duct (left side)

Disease Etiology

A complete understanding of the etiology of Zenker diverticulum formation is not available; its pathogenesis is multifactorial and entails cricopharyngeus muscle dysfunction and age-related tissue degeneration.

Zenker's diverticulum is a pulsion diverticulum resulting from:

1. Cricopharyngeal dysfunction: Impaired cricopharyngeal compliance, usually due to fibrotic changes, causes increased intrabolus pressure with swallowing. Incomplete relaxation of the upper esophageal sphincter during swallowing, hypertonic sphincter tone, or incoordination between pharyngeal contraction and sphincter relaxation all contribute.
2. Increased intrapharyngeal pressure: Repeated swallowing against a partially closed or poorly relaxed sphincter over years leads to progressive herniation at the weak point.
3. Mucosal herniation: The hypopharyngeal pressure increases, leading to herniation at Killian's dehiscence just above the cricopharyngeus.

Risk factors include:

• Advanced age (decreased tissue elasticity)
• Gastroesophageal reflux disease - there is a large body of evidence supporting an association with gastroesophageal reflux
• Hiatal hernia - patients with Zenker's diverticulum often present with a hiatal hernia
• Fibrosis of cricopharyngeus muscle

Classification by size:

• Small: <2 cm
• Medium: 2-4 cm
• Large: >4 cm

Histology

Histological section of a Zenker's diverticulum will reveal only the luminal mucosal layer and submucosal tissues. The lack of a muscular layer makes this a pseudodiverticulum (false diverticulum) rather than a true diverticulum.

Diagnosis

Patient History

Classic presentation (symptoms progress over years):

Dysphagia:

• Progressive difficulty swallowing, initially solids then liquids
• May have "two-stage" swallow (initial attempt fails, second succeeds)

Regurgitation:

• Undigested food, sometimes hours after eating
• Worse when lying down
• May occur spontaneously

Halitosis:

• Foul breath from decomposing food in diverticulum
• Often noticed by family members

Aspiration symptoms:

• Chronic cough, especially nocturnal
• Recurrent pneumonia
• Choking episodes

Other symptoms:

• Globus sensation (lump in throat)
• Borborygmi (gurgling sounds) in neck
• Weight loss (in severe cases)
• Hoarseness (rare, if recurrent laryngeal nerve compressed)

Physical Examination

Physical examination is often unremarkable but may show:

• Gurgling sounds: In neck during swallowing (pathognomonic when present)
• Palpable mass: Left side of neck (large diverticulum), may increase with swallowing
• Boyce sign: Laryngeal crepitus during neck palpation
• Malnutrition signs: In severe cases
• Pulmonary findings: If aspiration pneumonia present
• Laryngoscopy: May show pooling of secretions, signs of aspiration

Laboratory Tests

• No specific diagnostic laboratory test
• Nutritional assessment (albumin, prealbumin) if significant weight loss
• CBC, inflammatory markers if infection suspected

Imaging

Barium swallow with videofluoroscopy is the criterion standard for diagnosis. This study provides information about the size, location, and character of the mucosal lining of the Zenker diverticulum. Modified barium swallow studies may also be beneficial if the view is widened to include the entire cervical esophagus.

Barium swallow findings:

• Posterior outpouching from pharyngoesophageal junction at the C5-6 level
• Located ABOVE cricopharyngeus level (distinguishes from Laimer's Diverticulum and Killian-Jamieson Diverticulum)
• Fills with barium during swallowing; best seen on lateral view
• May show air-fluid level
• Patients with symptomatic disease usually have a posterior midline pouch >2 cm in diameter

CT of neck:

• Confirms anatomy
• Evaluates relationship to surrounding structures
• Screens for other pathology

Esophagogastroduodenoscopy (EGD):

• May visualize diverticulum entrance
• Caution: Risk of perforation if scope inadvertently enters diverticulum
• Useful to rule out esophageal malignancy
• Essential in surgical evaluation

Differential Diagnosis

Other diverticula of the pharyngeal and esophageal mucosa should be considered:

• Laimer's Diverticulum
• Killian-Jamieson Diverticulum
• Esophageal stricture
• Esophageal carcinoma
• Cricopharyngeal bar (achalasia)
• External compression (thyroid, lymph nodes)
• Globus pharyngeus (functional)
• Esophageal web

Management

Medical Management

There is no medical management that will significantly impact the development or worsening of a Zenker's diverticulum. Medical management is limited to the treatment of sequelae of the diverticulum, such as aspiration pneumonia.

Conservative measures (may be appropriate for poor surgical candidates):

• Small frequent meals
• Thorough chewing
• Drinking fluids with meals
• Upright positioning during and after meals
• Manual compression of diverticulum during swallowing
• Treatment of GERD

Surgical Management

Surgery is the definitive treatment for symptomatic Zenker's diverticulum. During surgery, it is vital to divide the cricopharyngeus muscle to relieve the elevated pressure zone and eliminate the pouch of the diverticulum.

Open Surgical Approach (Transcervical Diverticulectomy)

Technique:

• Left cervical incision along anterior border of sternocleidomastoid
• Dissection to identify diverticulum
• Cricopharyngeal myotomy (essential component)
• Diverticulectomy with stapled or sutured closure OR diverticulopexy (suspension) for smaller pouches

Advantages: Complete excision, direct visualization, allows complete myotomy decreasing recurrence

Disadvantages: Longer recovery, cervical incision, risk of recurrent laryngeal nerve injury, fistula risk

Endoscopic Approaches

Rigid endoscopic stapling (Dohlman procedure/staple-assisted):

• Diverticuloscope inserted to expose septum between diverticulum and esophagus
• Stapler divides septum, creating common cavity
• Includes cricopharyngeal myotomy

Flexible endoscopic septotomy:

• Performed with standard upper endoscope
• Uses various cutting devices (needle knife, argon plasma coagulation, etc.)
• May require multiple sessions

Endoscopic advantages: No external incision, shorter recovery, outpatient or short hospital stay, lower morbidity

Endoscopic disadvantages: May require multiple procedures, higher recurrence rate, not suitable for small diverticula (<2 cm), limited neck extension may preclude approach

Comparative Outcomes

A systematic review and meta-analysis found that compared with a surgical approach, endoscopic treatment resulted in shorter length of procedure and hospitalization (SMD -78.06 and -3.72, respectively), earlier diet introduction (SMD -4.30), and lower rates of complications (SMD -0.09). However, endoscopic treatment had higher rates of symptom recurrence (SMD 0.08).

A systematic review identified a failure rate of 18.4% for endoscopic and 4.2% for open approaches. The complication rate was 7% for endoscopic treatment and 11% for open surgery.

Cricopharyngeal Myotomy

• Essential component of treatment regardless of approach
• Addresses underlying pathophysiology
• Incomplete myotomy is associated with higher degree of symptomatic recurrence
• Performed with both open and endoscopic approaches

Outcomes

Complications

The main complication associated with a Zenker's Diverticulum is aspiration secondary to reflux of contents of the diverticulum. Patients will also often complain of halitosis.

Without treatment:

• Progressive dysphagia
• Aspiration pneumonia
• Malnutrition
• Perforation (rare, spontaneous)
• Squamous cell carcinoma in diverticulum (rare, 0.3-0.7%) - the Mayo Clinic reported a 0.4% incidence among 1,249 patients over 53 years

Surgical complications:

• Pharyngocutaneous fistula: 1-3% (open), <1% (endoscopic)
• Recurrent laryngeal nerve injury: 1-2% (open)
• Mediastinitis: Rare but serious
• Recurrence: 4-18% (varies by technique)
• Dental injury: Endoscopic approaches
• Esophageal perforation: Both approaches

Prognosis

Outcomes are excellent with appropriate treatment:

Open surgery:

• Symptomatic improvement: >90%
• Recurrence rate: 3-7%
• Mortality: <1%

Endoscopic approaches:

• Symptomatic improvement: 85-95%
• Recurrence rate: 10-18% (may need repeat procedure)
• Mortality: <0.5%

Factors affecting outcomes:

• Diverticulum size
• Surgical technique and experience
• Completeness of cricopharyngeal myotomy
• Patient comorbidities

Long-term considerations:

• Repeat imaging if symptoms recur
• Low threshold for repeat intervention
• Surveillance for malignancy not routinely recommended