Endoscopic treatment of Zenker’s diverticulum: a never ending (r)evolution

Friedrich Albert von Zenker was a German pathologist, who lived and worked in Erlangen, Germany, in the nineteenth century. In 1877, he meticulously described the precise anatomy and pathology of the posterior pulsion pharyngeal diverticulum that bears his name [1].

The symptoms of Zenker’s diverticulum, oropharyngeal dysphagia, regurgitation, and rumination, are caused by both the incomplete swallow-induced opening of the upper esophageal sphincter and the enlarged pharyngeal pouch.

Over the years, a variety of management approaches have been proposed. The primary aims of treatment are to both improve the pharyngo-esophageal outflow and eliminate the pharyngeal reservoir. Cricopharyngeal myotomy is the mainstay of treatment, regardless of any additional procedures that may be performed to eliminate the pharyngeal reservoir [2].

In recent years, the surgical, transcervical approach (a myotomy followed by diverticulectomy, diverticulopexy, or inversion) has largely lost currency in favor of more effective and safer transoral procedures.

The rigid endoscopic transoral approach was proposed as early as 1906 by the North American otolaryngologist Harris Peyton Mosher and improved in 1936 by the Swedish ear–nose–throat surgeon Gösta Dohlman, but only become popular a few decades later, in 1993, when the Belgian and British surgeons Jean-Marie Collard and Martin Hirsch simultaneously proposed a transoral single-stage cut and suture technique, using a laparoscopic stapler introduced through the rigid diverticuloscope. The rationale behind the transoral approach is that a septum, containing the cricopharyngeal muscle, divides the diverticulum from the esophagus. By dividing this septum, the cricopharyngeal muscle is cut, and the diverticulum becomes a single cavity with the esophagus, simultaneously eliminating food entrapment and outflow obstruction. Nevertheless, the preliminary placement of a rigid diverticuloscope is certainly difficult, especially in elderly patients, and is associated with some complications, including accidental perforation [1] [2] [3].

In 1995, the management of Zenker’s diverticulum underwent a revolutionary change, with the introduction of the flexible endoscopic approach. Shinichi Ishioka in Brazil and Chris JJ Mulder in The Netherlands reported on the first cases of cricopharyngeal myotomy and septotomy using a flexible endoscope [4] [5]. With this approach, orotracheal intubation is usually not necessary. More importantly, a flexible endoscope allows patients of any age to be treated, as well as those with severe comorbidities and those with limited jaw opening or neck mobility. This situation is especially frequent in elderly patients, where the placement of a rigid diverticuloscope is difficult or impossible [2] [3]. At least three different flexible endoscopic approaches have been described: a) free-hand, cap-assisted septotomy, b) flexible diverticuloscope-assisted procedure and, more recently, c) peroral endoscopy myotomy or Z-POEM.

“...the flexible endoscopic transoral approach, including all the different techniques and devices, is definitely reliable and should be considered before any alternative treatment for the vast majority of Zenker’s diverticula.”

Unfortunately, well-conducted studies that compare the different techniques are still lacking. When comparing the flexible endoscopic cricopharyngeal myotomy and the stapler-assisted procedure, similar clinical outcomes were reported; generally, endostapling was associated with a significantly longer procedure time compared with flexible endoscopic treatments [6].

The flexible endoscopic cricopharyngeal myotomy has some limitations, the main one being the dimension of the pharyngeal sac. The procedure is likely to be less effective in the case of very small (< 10 mm) or very large (> 5 cm) pouches. In the case of very small pouches, there is a certain risk of incomplete myotomy, as the septum is substantially shorter than the cricopharyngeal muscle. In contrast, in very large pouches, the septotomy can be insufficient to functionally exclude the diverticulum [7].

In 2016, in the wake of novel tunneling techniques used for the management of achalasia (POEM), Dr. Li described a novel procedure, Z-POEM, which includes the creation of a short submucosal tunnel in the hypopharynx, the identification of the cricopharyngeal muscle, followed by cricopharyngeal myotomy (within the submucosal tunnel), extending into the esophageal wall for a few centimeters until the bottom of the diverticulum is reached [8].

Needless to say this spectacular and innovating procedure can be the preferred approach for small diverticula, when alternative transoral procedures are difficult or ineffective. Preliminary published studies have reported promising results, though are limited by the exiguous number of patients included and by the short follow-up. 

In this issue of Endoscopy, Al Ghamdi et al. report on a large, retrospective, multicenter study that compared three different approaches to Zenker’s diverticulum: Z-POEM, and flexible and rigid endoscopic cricopharyngeal myotomy and septotomy [9]. A total of 245 patients were included in 12 centers during a 3-year period. The most common operation was Z-POEM (n = 119), followed by flexible (n = 86) and rigid (n = 40) endoscopic procedures. In the rigid endoscopic procedures, several techniques were used for the division of the septum, including electrocautery, laser, staplers, or harmonic scalpels. Flexible endoscopic procedures employed diverticuloscope-assisted and cap-assisted techniques.

The study is interesting and is the first multicenter study to compare different approaches to Zenker’s diverticula since the introduction of Z-POEM into clinical practice.

Clinical success was similar across the three study groups during a mean follow-up of 5 months (i. e. very short in truth!). Adverse events occurred in 30.0 % of rigid endoscopic procedures, 16.8 % of Z-POEM procedures, and 2.3 % of flexible endoscopic procedures (P < 0.05).

The study has many limitations, the most important being, obviously, the retrospective analysis, the inhomogeneous distribution of patients in the three groups, the short follow-up, and the variability in techniques and devices used in each study group.

Nevertheless, the study highlights the benefits and strengths of Z-POEM, the most recently developed endoscopic procedure. Currently, few centers in the world have numerically important experiences with Z-POEM: the procedure is novel (it was only developed in 2016) and the disease is relatively uncommon. However, the technical success of Z-POEM was 95 %, which is the same as that for the classic flexible endoscopic septotomy technique, which has been in practice now for 16 years. The rigid endoscopic procedures remain the most difficult to perform, with 87 % technical success and a very high complication rate. Furthermore, even if the differences are not statistically significant, the new-kid-on-the-block, Z-POEM, is also the most effective procedure, with a 93 % clinical success rate. Other studies showed slightly better outcomes for Z-POEM, but in this multicenter series, initial cases of Z-POEM at the various participating centers were also included.

Of course, we should take the findings of this study with a grain of salt, but we can take home two important messages. First, the flexible endoscopic transoral approach, including all the different techniques and devices, is definitely reliable and should be considered before any alternative treatment for the vast majority of Zenker’s diverticula. Second, even if many endoscopists are still completing their learning curve and the procedure is still evolving, the third-space approach of Z-POEM is extremely promising and can definitely be proposed as a first-line therapy for the management of Zenker’s diverticula.

Publication History

Article published online:
24 September 2021

• References

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