Zenker's diverticulum

INTRODUCTION — 

Zenker's diverticulum (ZD) is a sac-like outpouching of the mucosa and submucosa through Killian's triangle, an area of muscular weakness between the transverse fibers of the cricopharyngeus muscle and the oblique fibers of the lower inferior constrictor (ie, thyropharyngeus) muscle (figure 1).

This topic review will focus on clinical issues surrounding ZD. Other causes of dysphagia are discussed in:

●(See "Oropharyngeal dysphagia: Etiology and pathogenesis".)

●(See "Oropharyngeal dysphagia: Clinical features, diagnosis, and management".)

●(See "Approach to the evaluation of dysphagia in adults".)

TERMINOLOGY AND CLASSIFICATION — 

Esophageal diverticula are outpouchings of one or more layers of the esophageal wall.

●True diverticula contain all layers of the esophageal wall

●False diverticula contain only mucosa and submucosa

●Intramural diverticula are confined to the submucosa

Esophageal diverticula are classified based on their location in the esophagus:

●Near the upper esophageal sphincter.

•ZD is located above the cricopharyngeus muscle with the pouch extending posteriorly.

•Killian-Jamieson diverticulum is located below the cricopharyngeus muscle with the pouch extending anterolaterally (rare). The risk of intraoperative injury of the recurrent laryngeal nerve is high during surgical resection of Killian-Jamieson diverticulum because the recurrent laryngeal nerve usually runs next to the base of the diverticulum [1].

•Laimer's diverticulum is located below the cricopharyngeus muscle with the pouch extending posteriorly (rare).

●Near the midpoint of the esophagus (traction diverticulum).

●Immediately above the lower esophageal sphincter (epiphrenic diverticulum).

ZD is defined as a posterior "false" diverticulum that has a neck proximal to the cricopharyngeal muscle (image 1) [2,3].

EPIDEMIOLOGY AND PATHOGENESIS

Prevalence — The reported prevalence of ZD is between 0.01 and 0.11 percent. However, this is likely an underestimate as patients with diverticula may be asymptomatic [4]. ZD is male predominant (ratio 1:5) and typically seen in middle-aged adults and older adults in their seventh or eighth decade of life. The occurrence of ZD shows geographical variation and has been described more frequently in Northern Europe, North America, and Australia than in Southern Europe, Japan, or Indonesia [5]. A retrospective cohort study (n = 2736) from Finland reported an annual incidence of 2.9 per 100,000 person-years [6].

Etiopathogenesis — ZD emerges from a natural area of weakness in the muscular wall of the hypopharynx known as Killian's triangle, which is formed by the oblique fibers of the inferior pharyngeal constrictor (ie, thyropharyngeus) muscle and the cricopharyngeal muscle (figure 1). Killian's triangle is more prevalent in males than in females (60 versus 34 percent), and the dimensions of the triangle correlated with the dimensions of the body and the length and the descensus of the larynx [7].

It is hypothesized that for the development of ZD, a variety of circumstances predisposing to herniation within Killian's triangle must be present, such as disorders associated with altered upper esophageal sphincter function, abnormal esophageal motility, or esophageal shortening [8-11]. Increased intrabolus pressures observed in patients with ZD may be secondary to impaired bolus passage in combination with or as a result of gastroesophageal reflux disease [12-14].

In recent years, the cervical inlet patch (CIP) of heterotopic gastric mucosa in the upper esophagus has gained more attention and can present with dysphagia and chronic cough [15]. Both ZD and CIP are distinct yet potentially coexisting conditions, but evidence for a causative relationship remains circumstantial [16].

CLINICAL MANIFESTATIONS — 

Small diverticula can be asymptomatic. Oropharyngeal dysphagia is the presenting symptom in 80 to 90 percent of patients with ZD. Marked weight loss and malnourishment can occur in patients with longstanding dysphagia. The openings of large ZD are often aligned with the axis of the pharynx such that food is preferentially diverted into the diverticulum. When the pharyngeal sac becomes large enough to retain contents such as mucus, pills, sputum, and food, the patient may complain of halitosis, gurgling in the throat, appearance of a mass in the neck, or regurgitation of food into the mouth. In rare cases, the ZD may become so large that its retained contents may push anteriorly and completely obstruct the esophagus.

Complications of ZD are discussed below. (See 'Complications' below.)

DIAGNOSIS — 

ZD should be suspected in middle-aged or older adults with progressive dysphagia (usually to solids) and regurgitation of undigested food debris. The diagnosis of ZD is made on barium swallow examination. An upper endoscopy is not required to confirm the diagnosis but is recommended to exclude a concurrent malignancy or another alternative diagnosis. ZD, which has the endoscopic appearance of a separate lumen, may not always be apparent if small.

Imaging

●Fluoroscopy – ZD appears as an out-pouching at the posterior aspect of the pharyngoesophageal junction and are best seen on barium swallow examinations (image 1) combined with dynamic continuous fluoroscopy. In some patients, the entire first glass of barium taken will disappear into the confines of an especially large diverticulum. However, small diverticula can be missed if they are superimposed on the main column of barium in the esophagus. This can be avoided by rotating the patient during the examination.

●Ultrasound – An alternative method to diagnose ZD and to differentiate from a thyroid or neck mass is transcutaneous ultrasound. This technique might be a good alternative in people who experience difficulties in swallowing barium, provided the technique is in experienced hands [17-19].

Differential diagnosis — The differential diagnosis of ZD includes other causes of progressive dysphagia (eg, peptic stricture and esophageal carcinoma). ZD can be distinguished from these by imaging and upper endoscopy. The differential diagnosis and evaluation of patients with dysphagia is discussed in detail separately. (See "Approach to the evaluation of dysphagia in adults", section on 'Solids only with progressive symptoms'.)

MANAGEMENT — 

The goal of treatment for symptomatic ZD is to reduce the size of the diverticulum and improve pharyngeal motor function, thus improving the symptoms of dysphagia and regurgitation. The key intervention is division of the cricopharyngeus muscle that forms the septum between the esophagus and the pouch. Individual treatment differs by how the septum is accessed and divided.

Asymptomatic patients — Asymptomatic diverticula do not warrant treatment. Patients can be managed expectantly until symptoms occur or a diverticulum increases in size.

Symptomatic patients — Treatment is indicated for symptomatic ZD. Currently, there are three main treatment options for ZD: open surgery (eg, transcervical diverticulectomy, diverticulopexy with myotomy of the cricopharyngeus muscle, or diverticular inversion), rigid endoscopy (eg, endoscopic stapling or carbon dioxide [CO₂] laser treatment), and flexible endoscopy. The first two procedures are performed by otolaryngologists (ie, ear, nose, and throat surgeons) or thoracic surgeons, while flexible endoscopy is performed by interventional endoscopists.

First-line treatment — For most patients with a symptomatic ZD, we suggest flexible endoscopic treatment over rigid endoscopic or open surgical treatment [20].

Both flexible and rigid endoscopic approaches are less invasive than open surgery and are associated with shorter operation time and hospital stays, more rapid resumption of oral intake, lower complication rates, and easy access in case of prior neck surgery [21,22]. Some flexible endoscopies may be performed under sedation, although many still use general anesthesia to protect the airway from secretions during the procedure. Flexible endoscopy also avoids the need for neck hyperextension [23]. Many older adult patients with ZD have limited neck mobility, which makes rigid endoscopy difficult; the rigid endoscopic approach has a technical failure rate of 6 to 7 percent [24].

The limitations of open surgery and rigid endoscopy, combined with the higher complication rates of surgery and the >90 percent success rates of flexible endoscopic treatment, have led us to suggest flexible endoscopic treatment as the first-line treatment for ZD [20].

There are two types of flexible endoscopic treatments for ZD [25,26]:

●Flexible endoscopic septotomy (FES) involves a full-thickness incision of the mucosa, submucosa, and the muscular fibers that form the septum, resulting in the creation of a common cavity between the esophagus and the diverticulum. FES is the most commonly performed flexible endoscopic treatment of ZD and can be performed by experienced interventional endoscopists.

●Zenker's peroral endoscopic myotomy (Z-POEM) or peroral endoscopic septotomy (POES) is a newer flexible endoscopic technique for the management of ZD, which is considered the endoscopic equivalent of surgical myotomy [27-29]. Both Z-POEM and POES rely on submucosal tunneling to completely expose and dissect the septum [30]. Submucosal tunneling may be particularly suitable for treating small (<2 cm) ZD because the small pocket may disappear after the myotomy is performed.

Zenker's diverticula <2 cm — A small ZD with a septum less than 2 cm in size can be highly symptomatic and pose a significant therapeutic challenge due to the restricted operating space. A short septum may hinder the ability to completely dissect the cricopharyngeal muscle using the FES technique, as the septotomy is very limited in length. In this clinical scenario, a Z-POEM or POES technique could be preferred over FES [31,32]. Z-POEM and POES only differ by the entry point of the submucosal tunneling: in Z-POEM, a mucosal incision is made 2 cm proximal to the septum; in POES, it is made right over the septum [30].

Data comparing the efficacy of Z-POEM or POES with FES are emerging [26]. Available expertise in Z-POEM or POES is limited, though [33,34]. The Z-POEM technique is discussed in detail separately. (See "Peroral endoscopic myotomy (POEM)", section on 'POEM for Zenker's diverticula'.)

Zenker's diverticula >2 cm — For larger ZD (>2 cm), division of some of the mucosa is also required to create a common channel between the diverticulum and the native esophageal lumen, which ensures proper drainage of the ZD (image 2). In such patients, FES is commonly performed by experienced interventional endoscopists.

FES involves a full-thickness incision of the mucosa, submucosa, and the muscular fibers of the cricopharyngeus that form the septum in between the esophageal lumen and diverticulum, resulting in the creation of a common cavity between the two [35]. The objective is to create an overflow tract from the ZD to the esophagus (figure 2 and image 3 and image 2 and picture 1 and movie 1). (See 'Alternative treatment' below.)

●Procedure – FES is generally performed under monitored anesthesia care (deep sedation) or general anesthesia to ensure airway protection. CO₂ should be used for insufflation to minimize pneumomediastinum and subcutaneous emphysema [20]. Prophylactic antibiotics are not routinely required [36].

Adequate endoscopic exposure of the ZD septum is essential. This is usually achieved by the insertion of an orogastric tube (14 to 18 Fr) into the esophageal lumen during the procedure. The orogastric tube also protects the contralateral esophageal wall from thermal injury during sectioning of the ZD septum (image 3). However, exposure of the septum with the orogastric tube can be suboptimal, particularly in small diverticula or in those with a distorted axis with respect to the esophageal lumen. In that case, one can use a rigid guidewire instead.

Some endoscopists use a plastic overtube or a transparent hood attached to the tip of the endoscope to stabilize the septum and improve exposure [37]. In Europe and Canada, a commercially available soft diverticuloscope, which has been designed based on the otolaryngology experience with the rigid diverticuloscope, can also be used for the same purpose [38].

Using a knife or monopolar forceps, the initial cut or coagulation is made at the top of the ZD septum (movie 1). The transverse fibers of the cricopharyngeal muscle should be visualized (picture 1).

The cutting/coagulation should be performed in the midline of the septum. Mixed current (use Erbe setting Endocut) can be used for the initial cut and coagulation current for dissecting the muscle fibers. Other endoscopic cutting accessories developed for submucosal dissection (ie, hook knife, flush knife, hybrid knife) can also be used to cut the septum and muscle fibers [39-44]. The use of argon plasma coagulation for septal division is obsolete and reserved only for hemostasis [45].

To minimize the risk of perforation, the esophageal and diverticular lumens should be kept under direct vision at all times, which usually becomes easier after the initial cut has been made. Early in the learning curve, it is advisable to divide one-half to two-thirds of the ZD septum and then stop and repeat the procedure after a few weeks. Full myotomy is achieved when the buccopharyngeal fascia is reached. This is a shiny, thin, film-like layer [46]. Making a deeper cut results in perforation.

In order to treat or prevent perforation and shape the new funnel-like configuration of the ZD (image 2), the cut should be closed using endoclips, preferably in the midline of the wound (movie 1). These clips can also be used to achieve hemostasis if bleeding occurs. A clip-assisted technique, where prior to dissection with a needle knife, two endoclips were placed on either side of the ZD septum, has been used to prevent microperforations [47]. Data from a large retrospective cohort showed that preventive clipping did not influence the outcomes [36].

●Postprocedural care – The orogastric tube is left in place until the patient is fully awake. If no perforation or other complication is suspected clinically, the orogastric tube can be removed and oral fluid intake started. The diet can then be advanced within the next few days.

If, during the procedure, a large visible perforation occurs that is difficult to close with clips, we leave the orogastric tube in place to secure passage to the esophagus and better visualization in case reintervention is required. Conservative treatment with nasogastric tube feeding, antibiotics, and pain control is usually sufficient to heal the leak. Imaging studies are not very useful.

Follow-up radiologic studies of patients treated endoscopically for ZD are generally not indicated to evaluate postoperative results since they do not correlate with symptoms of dysphagia [48]. After endoscopic treatment, the diverticulum will still remain visible on radiographs as a residual pouch, but swallowed contrast will pass more easily due to the created overflow (image 2) [49].

With increasing experience in different centers, endoscopic diverticulotomy is becoming an outpatient procedure. However, based on the difficulty of the procedure and patient age and comorbidities, patients may require overnight observation [42,50].

Alternative treatment — Although flexible endoscopy is the first-line therapy for most symptomatic ZD, alternative therapies, either rigid endoscopy or open transcervical exploration, may be required when flexible endoscopy is either not available or not feasible due to anatomical or other reasons.

Rigid endoscopy — A transoral rigid esophagoscopy is associated with a lower rate of adverse events than the open surgical approach but has a higher rate of technical failure and recurrence in the setting of patient-related factors (eg, small ZD <3 cm, inadequate jaw opening, and restricted neck mobility) [23].

Rigid endoscopy is usually performed under general anesthesia. A Weerda diverticuloscope is used to expose the common wall between the diverticulum and the esophagus. Different techniques using a variety of coagulation and cutting devices, including CO₂ laser, endoscopic stapler, and basic or advanced bipolar forceps, can then be used to divide this septum between the esophagus and the diverticulum [5,51-55].

Open transcervical surgical approach — The decision to use an open surgical or endoscopic approach is made by clinicians on the basis of the ability to visualize the ZD and septum endoscopically, patient's body habitus, support of the ZD pouch against the posterior wall, and local expertise [33,56]. Short necks, decreased hyomental distance, and/or a high body mass index are most often associated with difficult exposures and require an open approach [57].

The choice of an open operation depends on the size of the ZD pouch and surgical/anesthesia risk.

●For patients receiving open surgical treatment, cricopharyngeal myotomy with diverticulectomy is the preferred operation in good surgical candidates. Diverticulectomy is a total diverticular pouch resection and is performed commonly in combination with cricomyotomy. The efficacy of myotomy is supported by a number of surgical series in which excellent or very good responses have been observed in 80 to 100 percent of patients [58-65]. Recurrence rates for symptomatic diverticula of 15 to 35 percent with diverticulectomy alone confirm the importance of cricopharyngeal myotomy performed at the time of surgery [66,67].

●In high-risk surgical patients or in moderate-size pouches, cricopharyngeal myotomy and diverticulopexy are often the treatments of choice to avoid the potential high-risk complications associated with a diverticulectomy [61,68]. The procedure involves suspension of the lumen of the diverticulum in the caudal direction such that the orifice is directed away from the hypopharynx, thereby preventing the entry of food and secretions. Moderate ZD is usually defined as 2 to 5 cm in size.

●Small symptomatic pouches can be treated with suspension diverticulopexy alone or cricopharyngeal myotomy alone [69]. Small ZD is usually defined as <2 cm in size.

OUTCOMES

Clinical success — In two systematic reviews and meta-analyses, clinical success rates were 82 to 87 percent with the endoscopic approach (mostly rigid endoscopy) versus 94 to 96 percent with open surgery, whereas the complication rate was 7 to 9 percent with the endoscopic treatment versus 11 to 15 percent with the open surgery [24,70]. By comparison, a systematic review and meta-analysis of studies on the flexible endoscopic approach reported a pooled success rate of 91 percent, an adverse event rate of 11.3 percent, and a recurrence rate of 11 percent [35].

While the two endoscopic techniques have not been compared directly in randomized trials, there may be a higher recurrence rate and need for revision with flexible as compared with rigid endoscopic technique. In a 2019 systematic review and meta-analysis of 115 studies (29 flexible endoscopy studies) that compared rigid and flexible endoscopic approaches, mortality, infection, and perforation rates were not significantly different [71]. Bleeding (20 versus <10 percent) and recurrence (4 versus 0 percent) were more likely after flexible endoscopic techniques. Dental injury and vocal fold palsy occurred only in the rigid endoscopic group but were rare.

Complications — Complications of ZD can arise from the disease itself (eg, aspiration, bleeding, fistulization), iatrogenic injury to the diverticulum due to nasogastric tube or endoscope insertion, and endoscopic or surgical procedures to fix the ZD.

Complications of ZD include aspiration pneumonia, ulceration and bleeding due to retained medication or foreign bodies, fistula between the diverticulum and trachea lumen formation, and vocal cord paralysis due to the pressure from retained food [72-74]. Squamous cell carcinoma (SCC) in the diverticulum is a rare complication with an incidence of cancer in ZD from 0.3 to 1.5 percent [75]. Risk factors for malignancy are older age, male sex, long-standing history, and larger diverticular size. Most of the available literature about SCC at the level of the diverticulum is, however, case reports [76-78].

Caution must be used during endoscopy or passage of nasogastric tubes because of the risk of inadvertent perforation of the diverticulum. In patients with a known ZD, it is advisable to intubate the esophagus under direct visualization. Endoscopes requiring blind passage (such as side-viewing endoscopes used for endoscopic retrograde cholangiopancreatography, endoscopic ultrasound endoscopes, and probes for transesophageal cardiac ultrasound) can be passed after an initial endoscopy with a forward-viewing endoscope and passage of an overtube or a guidewire [79]. Nasogastric tubes should be passed over a guide wire or under direct endoscopic visualization.

A ZD may prevent the passage of a wireless video capsule endoscopy [80]. If capsule endoscopy is required, the capsule can be placed in the duodenum by endoscopy to avoid this problem. (See "Wireless video capsule endoscopy", section on 'Contraindications'.)

Perioperative complications of ZD vary by the nature of the endoscopic or surgical treatment:

●Complications of the open transcervical approach for ZD include mediastinitis, vocal cord paralysis, pharyngocutaneous fistula, esophageal stenosis, and recurrent or persistent ZD. A review of the literature of 41 studies with more than 2800 patients in total showed an overall surgical morbidity of 11 percent [81]. Cervical infection (including mediastinitis) occurred in 2 percent of the cases, leak or perforation in 3 percent, and recurrent laryngeal nerve damage in 3 percent.

●Dental injuries, perforations, and recurrent laryngeal nerve paralysis are concerns with the rigid endoscopic technique [81,82].

●The most common postprocedural symptoms associated with flexible endoscopic treatments of ZD include pain or discomfort of the throat. In case of carbon dioxide or air leakage to the mediastinum caused by (micro) perforation during the procedure, patients may experience chest and/or back pain. In some cases, serious subcutaneous emphysema can cause temporary dysphagia, changed voice, and local neck pain. Symptoms usually subside after a few days. Large esophageal perforations are rare. Substantial bleeding is very rare. Other complications have been mainly related to sedation, such as periprocedural myocardial infarction and pulmonary complications. (See "Monitored anesthesia care in adults", section on 'Complications during monitored anesthesia care'.)

Recurrences — Regardless of the treatment modality used, recurrence of ZD is not uncommon. Predictors of symptom relapse that occurs within 48 months of endoscopic therapy include: pretreatment ZD size >50 mm, post-treatment ZD size >10 mm, and the length of the septotomy <25 mm [83].

The recurrence rate is generally higher after endoscopic treatment than open surgical treatment (29 percent flexible endoscopic versus 18 percent rigid endoscopic versus 4 percent open [24]) due to incomplete division of the septum [22].

The choice of treatment approach in patients with recurrent symptoms depends on the size of the residual diverticulum, the patient's surgical risk, the need for definitive treatment, and available expertise. Flexible endoscopic retreatment is preferred and may be effective in patients with an incomplete septotomy because a safer extension of septotomy is possible once an adhesion between the esophageal and diverticular walls has developed [20]. There are limited data to suggest that flexible endoscopic septotomy performs equally well in recurrent ZD and primary ZD [84]. (See 'First-line treatment' above.)

SOCIETY GUIDELINE LINKS — 

Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Zenker's diverticulum".)

INFORMATION FOR PATIENTS — 

UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topic (see "Patient education: Zenker's diverticulum (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Definition – Zenker's diverticulum (ZD) is a sac-like outpouching of the mucosa and submucosa through Killian's triangle, an area of muscular weakness between the transverse fibers of the cricopharyngeus muscle and the oblique fibers of the lower inferior constrictor (ie, thyropharyngeus) muscle (figure 1). ZD is defined as a posterior "false" diverticulum that has a neck proximal to the cricopharyngeal muscle (image 1). (See 'Terminology and classification' above.)

●Pathogenesis – The precise cause of ZD remains unsettled, but it occurs in a variety of circumstances predisposing to herniation within Killian's triangle, most notably disorders associated with upper esophageal sphincter dysfunction. (See 'Etiopathogenesis' above.)

●Clinical presentation – Oropharyngeal dysphagia is the presenting symptom in 80 to 90 percent of patients with ZD. When the pharyngeal sac becomes large enough to retain contents such as mucus, pills, sputum, and food, the patient may complain of halitosis, gurgling in the throat, appearance of a mass in the neck, or regurgitation of food into the mouth. (See 'Clinical manifestations' above.)

●Diagnosis – ZD should be suspected in middle-aged or older adults with progressive oropharyngeal dysphagia (usually to solids and liquids) or regurgitation of undigested food debris. The diagnosis of ZD is made on barium swallow examination. An upper endoscopy under direct vision should be performed to exclude malignancy. (See 'Diagnosis' above.)

●Management

•Asymptomatic patients – Asymptomatic ZD does not warrant treatment. Patients can be managed expectantly until symptoms occur or the diverticulum increases in size. (See 'Asymptomatic patients' above.)

•Symptomatic patients – For most patients with a symptomatic ZD, we suggest flexible endoscopic treatment as the first-line therapy (Grade 2C). Flexible endoscopic treatment is less invasive than open surgery and can potentially avoid general anesthesia and neck hyperextension required by rigid endoscopic treatment. (See 'First-line treatment' above.)

-For most patients with a symptomatic ZD <2 cm, we further suggest either Zenker's peroral endoscopic myotomy (Z-POEM) or peroral endoscopic septotomy (POES) (Grade 2C). For small diverticula, it is easier for Z-POEM or POES to expose and completely divide the cricopharyngeus muscle than standard flexible endoscopic septotomy (FES). (See 'Zenker's diverticula <2 cm' above.)

-For larger ZD (>2 cm), standard FES permits the division of some of the mucosa, which is required to create a common channel between the diverticulum and the native esophageal lumen and ensures proper drainage of the ZD. (See 'Zenker's diverticula >2 cm' above.)

Alternative therapies, either rigid endoscopy (with a stapler or laser) or open transcervical exploration, may be required when flexible endoscopy is either not available, or not feasible due to anatomical or other reasons. (See 'Alternative treatment' above.)

•Patients with recurrence – Recurrent symptoms may develop if a myotomy has been inadequate or if there is reapposition of the cut muscle edges. Recurrence is more likely in patients with wide diverticula. Flexible endoscopy is the usual approach to recurrent ZD. (See 'Recurrences' above.)

ACKNOWLEDGMENT — 

The UpToDate editorial staff acknowledges Bradley Schiff, MD, Stijn Van Weyenberg, MD, and Chris Mulder, MD, who contributed to earlier versions of this topic review.