Diverticula of the esophagus are a rare entity, with a prevalence that ranges between 0.06% and 4%.1,2 Esophageal diverticula are classified according to their location along the esophagus (pharyngoesophageal, midesophageal, or epiphrenic), and the mechanism of formation (pulsion or traction). Most common diverticula are those located in the pharyngoesophageal and epiphrenic locations. These are usually pulsion diverticula in which an increase of intraluminal pressure leads to herniation of mucosa and submucosa through the muscular layer resulting in a false diverticulum. Mid-esophageal diverticula are commonly traction diverticula. These are much less frequent and are the result of a focal traction of all layers (mucosa, submucosa, and musculature) of the esophageal wall by a periesophageal inflammatory process resulting in a true diverticulum.
Zenker diverticula are the most common diverticula of the esophagus. These arise in an area of muscular gap at the transition of the cricopharyngeal muscle and the inferior constrictors of the pharynx (Killian triangle) (Fig. 21-1), and are more frequently found on the left side of the esophagus due to the slight convexity of the esophagus to the left. Pathophysiologic mechanisms for this condition include muscular weakness and upper esophageal sphincter (UES) dysfunction. UES dysfunction is characterized by incomplete relaxation of the UES, increased intrapharyngeal pressure, and discoordinated pharyngeal contractions.3–5 Gastroesophageal reflux is present in up to 95% of patients and may be related to esophageal longitudinal muscle reflex contraction and consequent widening of the gap between pharyngeal constrictors and cricopharyngeal muscles6 or spasm of the UES.7
Cervical dysphagia is the most common presenting symptom and is often associated with regurgitation, halitosis, choking, chronic cough, hoarseness, gurgling, or aspiration pneumonia. Findings on physical examination may include the Boyce sign (a neck mass gurgling on palpation) and weight loss. The presence of progressive dysphagia, odynophagia, hemoptysis, and hematemesis is more suspicious for a malignancy and may be a squamous cell cancer arising from the diverticulum (incidence up to 1.1%).
Diagnostic tools include:
Barium esophagram is performed to assess size and location of the diverticulum and the size of the diverticular neck. In addition, it determines the distance from the diaphragm, therefore giving the surgeon the possibility of choosing between a laparoscopic or thoracoscopic approach.
Upper endoscopy is mandatory in order to rule out the presence of cancer or other esophageal diseases and to evaluate signs of reflux
Esophageal manometry is important to define the underlying esophageal motility disorder. We usually obtain this test in all patients, even though some surgeons deem that it is not mandatory, in the belief that a primary esophageal motility is always present. The most common underlying disorder is achalasia, followed by diffuse esophageal spasm and nutcracker esophagus.
Main indication for treatment is to address the patient’s symptoms from the diverticulum. The decision for intervention is made regardless of the size of the diverticulum, as it is mostly the underlying motility disorder that determines the symptom severity. However, some advice an operation also in the absence of symptoms to prevent the risk of aspiration.
Several treatment modalities directed at treating the motility disorder and at managing the diverticulum have been proposed:
Cricopharyngeal myotomy (CPM) alone
CPM and diverticulectomy
CPM and diverticulopexy
CPM and diverticular inversion
Diverticulectomy alone
Diverticulopexy alone
Diverticular inversion alone
In our experience, any procedure performed without a CPM results in an unacceptably high incidence of recurrent symptoms. Traditionally, these procedures have been performed through a left cervical incision. More recently, minimally invasive transoral endoscopic techniques have been developed.
This traditional approach is usually performed under general anesthesia, but can be accomplished with a cervical block and sedation. The diverticulum is either resected (diverticulectomy) or suspended and fixed to the prevertebral fascia (diverticulopexy), or invaginated into the esophagus.
In the past, diverticulectomy was performed with hand-sewn sutures, and was technically challenging with a risk of leak. The introduction of staplers has significantly reduced the risk of esophageal leak and mediastinitis (1.7%). Other risks of stapled diverticulectomy include recurrent laryngeal nerve injury, recurrence, and wound hematoma.8 Most surgeons advocate the addition of a CPM to the diverticulectomy.9
Diverticulopexy consists of fixation of the sac of the diverticulum to the pre-vertebral fascia or pharyngeal muscles above the neck of the diverticulum. The advantage of diverticulopexy over diverticulectomy is that the hypopharyngeal mucosa is left intact, eliminating the risk of leakage, with shorter hospital stays.10
Diverticular inversion is an alternative technique: the diverticulum is invaginated into the esophageal lumen and the neck is closed by using a purse-string suture. As for diverticulopexy, the hypopharyngeal mucosa is not breached. Hospital stay is shorter and complication rate lower after inversion than diverticulectomy.11
The rationale of performing a CPM is to relieve the functional obstruction distal to the diverticulum, thus reducing the risk of esophageal leak following diverticulectomy and recurrence of the diverticulum. The CPM is also critical to relieving the symptoms. This procedure is performed by gently incising the cricopharyngeal muscular fibers until reaching the underlying hypopharyngeal mucosa. The extension of CPM is debated,10,12,13 but usually ranges between 3 and 6 cm below the crycopharyngeus muscle. Visualization of the muscular layers and mucosa may be enhanced by the placement of a bougie dilator in the esophagus prior to starting the myotomy. Perioperative complications include recurrent laryngeal nerve injury, pharyngocutaneous fistula, mediastinitis, and hemorrhage.8
Currently, there are no randomized controlled trials comparing the different open approaches to Zenker diverticulum. As a consequence, the evidence supporting one approach over the other is limited. Small (1-2 cm) symptomatic diverticula can be safely treated with CPM alone, since most of these resolve after myotomy. The choice of surgical treatment for larger diverticula (2-4 cm) is not standardized and is left to the surgeon’s preference,14 but most commonly includes a CPM with diverticulectomy or diverticulopexy. To date, a diverticulectomy performed using staplers in association with a CPM is considered the approach of choice for diverticular larger than 4 cm since this is associated with very low fistula rates (1%-1.7%).15 Some would advocate resection to also eliminate the risk of cancer arising from the diverticulum.
The goal of endoscopic transoral surgery is to sharply divide the common wall (septum) that separates the esophageal lumen and the diverticulum (diverticulotomy). A cricopharyngeal myotomy is automatically performed, since the common wall includes the cricopharyngeal muscular fibers. The first endoscopic approach to Zenker diverticulum with esophagodiverticulotomy was reported in 1917.16 It was then abandoned due to the high rates of mediastinitis and death, until 1960 when Dohlman and Mattsson demonstrated very low rates of mediastinitis rate and recurrence by using electrocautery.17
Endoscopic diverticulotomy is accomplished under general anesthesia in patients with adequate oral access and the absence of both neck mobility limitations and macroglossia. Endoscopic exposure is very limited in patients with a short neck, a short hyomental distance, and severe obesity, leading to a high rate of conversion to open surgery.18 In addition, endoscopic diverticulotomy may result in incomplete myotomy in cases of small (<3 cm) diverticula, since only a few muscular fibers are contained in the short septum.15,19,20 Some surgeons consider a very large diverticulum a contraindication to endoscopic diverticulotomy, since laser, argon plasma coagulation (APC), and diathermy are associated with higher risk of bleeding, and the use of several staple cartridges can lead to a higher risk of leak.
The endoscopic diverticulotomy can be performed by a flexible or rigid endoscope. Briefly, the endoscope is advanced down to the esophagus under direct vision until the septum is between the two valves of the endoscope. Four techniques have been described for the division of the septum for rigid diverticulotomy9:
Electrocautery. The overall morbidity (subcutaneous emphysema and mediastinitis) and mortality rates reported in the literature are about 8% and 0.2%, respectively. Electrocautery has been replaced by CO2 laser and stapler techniques.
CO2 laser. This technique is associated with limited focal tissue trauma. The reported complications and mortality rates are 9.3% and 0.2%, respectively. Most common complications are subcutaneous emphysema, mediastinitis, fistula, and bleeding.
Linear stapler. The main limitation of this approach is the size of the diverticulum: poorer outcomes are reported in patients with diverticula smaller than 3 cm. The overall morbidity rate is 7.1%, while death is reported in 0.3% of cases. Most common complications are dental injury, esophageal mucosal injury, and esophageal perforation.
Harmonic scalpel. This approach has been recently introduced in the clinical practice. It involves the use of ultrasonic energy to cut and seal tissues. Large studies are needed to validate this technique.
Flexible endoscopic diverticulotomy was first reported in 1995.21,22 It can be performed under conscious sedation with no need for general anesthesia and neck extension. This approach is appealing in patients with comorbidities that complicate general anesthesia and in patients with anatomical features that prevent good exposure.
The septum division can be achieved through four different techniques:
Needle-knife incision
Hook-knife incision
APC
Monopolar forceps
Repeat sessions are common to reduce the risk of perforation. Overall morbidity rate is 15% with no deaths reported in the literature. Complications include subcutaneous cervical emphysema, esophageal perforation, and bleeding.9 Short-term studies demonstrate recurrence rates ranging between 0% and 35%; long-term studies are needed to understand the role and outcomes of this approach.9
To date, there are few studies (no randomized controlled trials) comparing open and endoscopic approaches. The results of these studies show that endoscopic surgery is associated with shorter operative time, lower morbidity, and shorter hospital stay than open surgery. Symptom relief rates are similar after both approaches.9,15,23–25 However, the heterogeneity of these studies in inclusion criteria, sample size, and length of follow-up do not allow for any definitive conclusions.
In summary, several options are available for the surgical treatment of Zenker diverticula. Because each treatment option has advantages and disadvantages, patient selection is key to achieving satisfactory short- and long-term outcomes. In the absence of a high level of evidence, there is no consensus regarding the best approach, and a “tailored” approach is advocated.
Mid-esophageal diverticula are a rare entity. They are often associated with mediastinal granulomatous disease, and these may develop secondary to traction exerted by inflamed mediastinal lymph nodes or malignancy.
Mid-esophageal diverticula are often asymptomatic and incidentally diagnosed on a barium swallow or upper endoscopy. An esophageal manometry is usually obtained to assess the presence of an esophageal motility disorder, which is detected in about 90% of patients.2,26,27
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