CHAPTER 74 Zenker’s Diverticulum

• Zenker’s diverticulum is the most common of the hypopharyngeal diverticula.

• Patients with this disorder most commonly present with dysphagia with food regurgitation.

• Diagnosis is confirmed by contrast radiography of the pharynx and esophagus.

• Treatment is directed toward elimination of symptoms and prevention or treatment of complications such as aspiration and malnutrition.

• Endoscopic treatment with the staple technique has proved to be an effective and safe method of therapy and should be considered the first-line approach.

• Any external surgical approach to treatment should include a cricopharyngeal myotomy.

• Regardless of technique, the most significant complication of surgical therapy is perforation of the hypopharynx or esophagus with associated mediastinitis.

Esophageal diverticula are classified on the basis of anatomic location (pharyngoesophageal, midesophageal, or epiphrenic) and mechanism of origin (pulsion or traction). Traction diverticula are a result of pulling forces external to the esophagus that are secondary to inflammatory or neoplastic processes and usually occur on the anterior wall of the esophagus near the bifurcation of the trachea. In contrast, pulsion diverticula are a result of herniation of esophageal mucosa and submucosa through an area of weakened esophageal musculature. Of the various types of esophageal diverticula, Zenker’s diverticulum (ZD), a pulsion-type diverticulum, is one of the most common symptomatic esophageal diverticula, with an annual incidence of 2 per 100,000 people per year, with men being affected 2 to 3 times more commonly than women.¹^–⁶ For patients referred for an examination of the upper gastrointestinal tract, the incidence can reach 1 in 1000.^4,^6,⁷ ZD is extremely rare in Asia and Africa, where gastroesophageal reflux disease is also uncommon, suggesting that reflux may play a role in its etiology.^5,^7,⁸ Most esophageal diverticula are acquired lesions found in adults, particularly in the seventh and eighth decades. Pediatric hypopharyngeal diverticula along with true ZD are extremely rare, with most cases being congenital in nature and fatal secondary to massive aspiration pneumonia.⁹^–¹⁹

Zenker’s diverticulum is classically defined as a pulsion diverticulum between the cricopharyngeal muscle and inferior constrictor muscle in an area of weakness called Killian’s dehiscence or triangle, first described by Killian ²⁰ in 1907 (Fig. 74-1). However, there are other areas of weakness where pulsion diverticula may form, including Killian-Jamieson’s area, between the oblique and transverse fibers of the cricopharyngeal muscle, and Laimer’s triangle, formed between the cricopharyngeal muscle and the most superior esophageal wall circular muscles (Fig. 74-2).²¹ More rarely, pharyngoceles may be found in the posterolateral or lateral areas of the pharynx and hypopharynx (Fig. 74-3).²² Cases of double pharyngeal pouches have also been described (Fig. 74-4).²³ Interestingly, ZD is found almost exclusively in humans, a fact hypothesized to be secondary to the large size and relatively caudal cervical location of the larynx in comparison with lower animals.^8,²¹ The caudal location of the larynx results in an oblique orientation of the pharyngeal constrictor muscles, resulting in regions of weakness. Such muscular vulnerabilities are absent in animals because the pharyngeal and esophageal musculatures have a coherent parallel orientation throughout the upper aerodigestive tract. Indeed, ZD has been found in only one animal, the Mangabay monkey, in a single case so far.²¹

Figure 74-1. Large Zenker’s diverticulum discovered by Zenker during an autopsy on a 67-year-old man. Drawing from Krankheiten des Oesophagus by Zenker and von Ziemssen, 1877.

(From Westrin KM, Ergun S, Carlsoo B. Zenker’s diverticulum—a historical review and trends in therapy. Acta Otolaryngol [Stockh]. 1996;116:351-360.)

Figure 74-2. Types of esophageal diverticula. A, Killian’s triangle: region between the cricopharyngeal and inferior constrictor muscle. B, Laimer’s triangle: region between the cricopharyngeal and most superior esophageal circular muscle. C, Killian-Jamieson’s triangle: region between the oblique and transverse fibers of the cricopharyngeal muscle. D, Lateral pharyngocele: variable location above and lateral to the cricopharyngeus.

Figure 74-3. Left lateral pharyngocele in a 45-year-old man. A, Barium swallow study, anterior view. A faint outline of the diverticulum can be seen in the left neck anterior and superior to the thyroid cartilage (arrowheads). Barium is outlining the medial wall of the diverticulum. B, Barium swallow study, lateral view. C, Direct laryngoscopy view demonstrating pharyngeal pouch. Spatula probe is within pouch. D, Direct laryngoscopy view after endoscopic staple diverticulostomy. E, epiglottis.

Figure 74-4. Barium swallow study revealing a double esophageal diverticulum. A, Anterior view. This 80-year-old woman was found to have a 3-cm Zenker’s diverticulum (arrow) and a 0.5-cm right Killian-Jamieson diverticulum (arrowhead). B, Lateral view. Patient underwent successful endoscopic staple diverticulostomy of the Zenker’s diverticulum. No attempt was made to correct the remaining diverticulum.

Theoretically, a diverticulum herniates to the side of less resistance. Accordingly, it is hypothesized that ZD is more prone to herniate to the left because the carotid artery is more laterally located on this side of the neck, making it less adherent to the adjacent prevertebral fascia, and because there the cervical esophagus has a slight convexity to the left.^21,²⁴ According to one series, although two thirds of Zenker’s diverticula are found in the midline, nearly 25% protruded to the left, and only 10% to the right.^25,²⁶

Presentation

Patient history alone may raise suspicion for ZD. The predominant symptom is progressive dysphagia, which may occur in excess of 90% of patients presenting with the disorder.²⁷ Regurgitation of food even hours after a meal, unprovoked aspiration, and noisy deglutition (borborygmi) specifically suggest ZD. Other symptoms are belching, hypopharyngeal mucus collection, halitosis, choking, coughing, hoarseness, globus pharyngeus, weight loss, and recurrent respiratory infections. Symptoms may last for weeks to many years before diagnosis and are generally more severe with a larger ZD. Minimal physical findings may include mucus pooling in the hypopharynx that initially clears with swallowing then recurs, emaciation or dehydration, and, only rarely, Boyce’s sign, a swelling in the neck that gurgles on palpation.²⁸ However, it is more often the case that patients are without any specific findings on physical examination. Diagnosis is confirmed by barium swallow radiography, which can also define the size and position of the sac (Fig. 74-5). Fiberoptic endoscopy is also performed to help rule out other potential causes of dysphagia (Table 74-1). Occasionally, ZD may be first discovered during esophagogastroduodenoscopy or rigid cervical esophagoscopy as an incidental finding during the course of a gastrointestinal evaluation. The size of the sac may range from less than 1 cm to a truly enormous 12 cm or more. Rarely, a large diverticulum may be seen on a regular chest radiograph (Fig. 74-6).

Figure 74-5. Zenker’s diverticulum (arrow) in a 63-year-old patient who underwent a barium swallow study. A, Anterior view. B, Lateral view.

Table 74-1 Differential Diagnosis of Dysphagia

Congenital or acquired	Esophageal stenosis, stricture, web
	Extrinsic compression from neck mass
	Carcinoma
	Trauma or iatrogenic (prior surgery)
	Inflammatory or infectious masses
	Tumor
	Plummer-Vinson syndrome
	Esophageal diverticulum
Motility disorders	Achalasia
Motility disorders	Esophageal spasm
Muscular incoordination	Myasthenia gravis
	Muscular dystrophy
	Thyrotoxicosis
	Carcinomatosis
Central neuropathic	Stroke
	Bulbar palsy
	Trauma
Peripheral neuropathic	Trauma
	Neuritis
	Collagen-vascular disorders
Idiopathic	Idiopathic

Figure 74-6. A and B, Chest radiographs of a 75-year-old patient with a 6-cm Zenker’s diverticulum. A, Before barium swallow. Note the hazy soft tissue mass in the right upper lung field (arrowheads) representing the Zenker’s diverticulum. B, After barium swallow. An air-fluid level can be seen within the Zenker’s diverticulum. C, Barium swallow study shows the diverticulum (arrow).

Through the years, physicians have attempted to classify ZD on the basis of contrast radiology findings (Table 74-2). In 1930, Lahey²⁹ described three stages based on radiologic appearance. Morton and Bartley,³⁰ along with subsequent writers, also described three stages but based them on size.³¹ van Overbeek and Groote⁵ used cervical vertebral bodies as a standard for comparison rather than absolute size measurements. Brombart and Monges³² expanded the classification into four stages, incorporating size, appearance, and stage of deglutition. Other workers have created increasingly more complex categories incorporating elements from both Brombart and Monges’s and van Overbeek and Groote’s systems.³³ Although useful in terms of classifying ZD, these arrangements have limited clinical utility.

Table 74-2 Zenker’s Diverticulum Classification Schemes

Pathophysiology

Although it is widely accepted that ZD is an acquired pulsion diverticulum, considerable controversy exists about the mechanism of its formation. Ludlow ³⁴ in Bristol, England, gave the first anatomic description of a pulsion diverticulum of the hypopharynx in 1769. He believed that this condition was induced in his subject by trauma after the swallowing of a cherry stone. Subsequent pathologists hypothesized traumatic rupture or burn, congenital upper esophageal stricture, thyroid goiter, or foreign bodies as triggers for ZD formation.²¹ It was not until 1877 that these hypotheses were rejected as erroneous and the basic pathophysiology was described by, and the diverticulum named after, Zenker, a German pathologist.³⁵ The original German description was later translated into English in New York in 1878, allowing wider dissemination of Zenker’s findings.²¹ However, before Zenker, Bell³⁶ (best known for describing facial nerve palsy) proposed in 1816 that incoordination of the inferior constrictor muscle against a closed cricopharyngeal muscle resulted in this type of outpouching at regions of inherent weakness. This etiology was later supported by other researchers.³⁷^–⁴⁶ Similarly, the congenital theory describes an unusually weak or large Killian’s triangle from birth that with time herniates with normal pharyngeal contraction.⁴⁷ Variations on this theme for the mechanism of formation of ZD have been debated ever since.

Patterson ⁴⁸ in 1919 first proposed cricopharyngeal achalasia as an etiology for ZD. Others noted a higher incidence of reflux and hiatal hernia in patients with ZD as well as epidemiologic observations that ZD occurs predominantly in populations with a high incidence of reflux, suggesting a possible relationship between the two.^7,⁴⁹ Several writers in the early 1970s suggested that spasm or persistently elevated resting tone of the cricopharyngeus secondary to reflux could cause ZD, although others refuted a direct causal association.^7,⁴⁹^–⁵¹ On the basis of histologic studies, Lerut⁵² in 1988 proposed a structural abnormality of the cricopharyngeal muscle itself. Cook and associates⁵³ in 1992 suggested partial, but incomplete, opening of the cricopharyngeal muscle because of fibroadipose tissue replacement as an etiology. Six years later, Walters and colleagues⁵⁴ proposed that ZD might be a manifestation of central or peripheral neurologic disease. Regardless of the theory, the cricopharyngeal muscle is the common theoretical culprit behind the formation of ZD, and whether to address this muscle during surgical management has been debated through the years.⁵⁵

Management

The treatment of ZD, as well as other forms of hypopharyngeal diverticula, is surgery. The presence of ZD is an additional risk factor in the overall health of the elderly patient, who may have concomitant pulmonary, cardiac, and other morbidities. With symptomatic ZD, the patient may have persistent aspiration causing deterioration of pulmonary function. Furthermore, with severe symptoms of dysphagia and aspiration, patients with ZD often become cachectic and dehydrated because of fear or inability to eat or drink. Definitive surgical management is mandated in these patients to prevent continued pulmonary compromise and malnutrition. Generally, all operative procedures addressing esophageal diverticula should be performed with the use of general anesthesia and as elective operations before complications have occurred. However, surgery may become urgent once problems have arisen and a patient’s condition is unlikely to be optimized before definitive treatment. In these patients, it is also important to fully evaluate and treat for other etiologies of dysphagia to obtain maximal benefit from surgery (see Table 74-1). Surgery is not necessary if the patient is asymptomatic or if the diverticulum is causing the patient minimal, if any, problems, but the patient does require long-term monitoring.

External Techniques

History

A variety of open, external surgical approaches to treating ZD have been performed, with and without the inclusion of cricopharyngeal myotomy. The first-recorded, but unfortunately fatal, treatment was performed in Vienna in 1877 by Nicoladoni,⁵⁶ who established a fistula to drain the sac, a procedure Bell³⁶ first proposed in 1816. Zenker and von Ziemssen³⁵ in 1877 recommended dilations of the esophageal inlet.²¹ Niehans⁵⁸ unsuccessfully attempted ZD excision in 1884. This procedure, first suggested by Kluge in 1850, resulted in the death of his patient from hemorrhage from the superior thyroid artery.^21,⁵⁷ Wheeler,⁵⁹ 2 years later, successfully excised a diverticulum. Kocher⁶⁰ in 1892 performed a diverticulectomy with primary closure. Girard⁶¹ in 1896 inverted the diverticulum, a procedure first described by Keyrat in 1866.²¹ Schmid⁶² in 1912 described the method of diverticulopexy, which was performed by Hill⁶³ in 1917. Unfortunately, these procedures, which often necessitated multiple stages, were associated with high mortality, particularly before the discovery of antibiotics to help reduce the morbidity and mortality. With technical advances and the availability of antibiotics, one-stage procedures became standard.

Despite the numerous different theories on the formation of ZD, the vast majority point toward the cricopharyngeal muscle as the etiologic factor. It thus follows that performing a cricopharyngeal myotomy does have a logical role in the surgical management of ZD. Although Richardson ⁶⁴ in 1899 performed the first cricopharyngeal myotomy with good results, albeit accidentally, it was not until 1936 that Aubin⁶⁵ proposed cricopharyngeal myotomy as a useful adjunct to surgical diverticulectomy. Instead of a myotomy, Lahey⁶⁶ in 1946 recommended cricopharyngeal dilation. Beginning in the 1950s, performance of a myotomy became a planned component of the surgical treatment of ZD and, in some cases, the sole treatment.^1,⁶⁷ It is now commonly accepted that surgical treatment of ZD without a cricopharyngeal myotomy is associated with a high recurrence rate.^39,^55,^57,⁶⁸^–⁷¹

Procedure

Generally, all external procedures (excluding cricopharyngeal muscle dilation) use a transcervical approach to the ZD, using a left lateral neck incision unless the ZD is found on the right side by preoperative barium esophagram. Before incision, however, cervical esophagoscopy is performed to identify the diverticulum and pack it with gauze to help in identification during transcervical surgical exposure. An esophageal dilator is inserted into the esophagus under direct visualization to assist in cricopharyngeal myotomy and to minimize the risk of esophageal stenosis. A nasogastric feeding tube is also inserted to be used for feeding after surgery.

The standard incision is usually made along the anterior border of the sternocleidomastoid muscle from the level of the hyoid bone to several centimeters above the clavicle. However, a curvilinear transverse incision along a neck crease between the hyoid and clavicle is preferable for cosmesis (Fig. 74-7). Subplatysmal flaps are then raised, followed by lateral retraction of the sternocleidomastoid muscle. The fascial attachments along the anterior border are divided. The strap muscles may be retracted anteromedially, but for better exposure, the anterior belly of the omohyoid muscle may be divided inferiorly. As blunt dissection is carried out to expose the posterior aspect of the pharynx, larynx, and esophagus, the recurrent laryngeal nerve is identified and protected before the thyroid vessels are ligated and divided, if necessary. Once the diverticulum is identified and freed from the surrounding tissues down to its base attachment to the esophagus, a long cricopharyngeal myotomy is performed. The pouch itself can then be excised, inverted, or suspended by a suturing or stapling technique (Figs. 74-8 and 74-9).⁷²^–⁷⁴ Each of these techniques has had its advocates.^2,^30,^68,^72,⁷⁵^–⁸² For small diverticula (1-2 cm), a cricopharyngeal myotomy alone may be sufficient.^28,^83,⁸⁴ The patient generally is fed postoperatively through a feeding tube for several days, after which an oral diet may be resumed.