Endoscopic therapy for Zenker diverticulum - the good and the bad

For decades, diverticulectomy and cervical myotomy using the open (cervical) approach was the treatment of choice for Zenker diverticulum. A minority of surgeons (in particular ENT specialists), however, had applied endoluminal treatment for many years; endoluminal dissection had been first introduced by Mosher in 1917. In the course of time, the tools changed, from scissors to CO₂ lasers, argon beams, and so on, but the technique of internal dissection of the threshold between the diverticulum and the esophageal lumen never really became popular.

This changed dramatically with the introduction of linear stapling devices. In contrast to mere dissection (with laser, argon beam, or needle-knife), the application of a linear stapler seals the edges of the incision and, in particular, the end of the dissection line at the bottom of the diverticulum. Endoluminal treatment now appeared to be sufficiently secure and safe, even to surgeons who had previously been very skeptical because of the risk of mediastinitis. Endoluminal stapling was established as an acceptable alternative to the open approach.

A few years later, endotherapy of the diverticulum using flexible endoscopy was introduced. General anesthesia and hyperextension of the head were no longer necessary to do more or less exactly what had been done before with the scissors, the laser, or the argon beam.

Future studies will have to demonstrate whether the long-term results are comparable, and if they are, endoscopic treatment would represent a significant step forward [1]. Nevertheless, some issues still need to be discussed before a sound evidence base is developed. The first question is whether endoluminal therapy is really as good as open surgery, and the second concerns the operative technique of endoluminal dissection.

The size of the diverticulum plays a key role but, most remarkably, is seldom considered. A complete division of the cricopharyngeal muscle can only be accomplished in the case of a diverticulum classified as Brombart III or IV. Otherwise, the wall separating the diverticular and esophageal lumina is too short. Granted that most endoscopic studies are confined to larger diverticula, it has to be kept in mind that smaller diverticula (Brombart I and II) are not suitable for endoluminal treatment.

The “Achilles heel” of endoluminal treatment of larger diverticula is the lower part of the separating wall. The lowest point of the diverticulum is a considerable distance from the esophageal wall. If cutting is done right down to the bottom, the mediastinum will, inevitably, be opened.

Accordingly, a relatively long residual spur has to be left at the bottom of the common cavity, and this is the cause of relapse in most cases. This navigation between Scylla and Charybdis (with too long a residual spur resulting in persisting dysphagia or too long a cut leading to mediastinitis) is difficult. Since most surgeons prefer to stay on the safe side, it is not surprising that, compared with open surgery, endoluminal therapy yields disappointing results in small diverticula [2].

On the other hand, for even large or very large diverticula, mere dissection of the separating wall cannot be recommended unreservedly. Treatment with a laser, argon beam, or diathermy knife of a giant diverticulum reaching deeply into the mediastinum carries the danger of severe bleeding from major vascular structures. In these cases, a stapling endodissection is probably considerably safer.

Flexible endoscopic dissection is certainly a very promising approach for the high risk elderly patient who particularly benefits from a short procedure without general anesthesia and without the need for hyperextension of the head - provided that the size of the diverticulum is adequate. The four papers in this issue of Endoscopy clearly demonstrate the feasibility of this approach [3] [4] [5] [6]. However, there is no doubt that the optimal technique has still to be identified. As in surgery, the variety of different techniques is an indicator that none of them can yet be considered “ideal.” The series presented are not controlled and are comparatively small with a short follow-up (recurrences frequently become clinically manifest after more than two years). If a single method is considered - as in the papers of Vogelsang, Christiaens, Rabenstein, and their co-workers [3] [4] [5] - the results are acceptable. As soon as two different approaches are compared, as in the paper of Costamagna et al. [6], the outcome of at least one of them appears to be dramatically worse. Accordingly, we completely agree with the recommendation for a prospective controlled trial of the most important variants of flexible endoscopic treatment. If the “best one” is defined (with an accurate description of the size of the diverticulum and of the outcomes), a good basis would exist for the first time for comparison with competitive options such as stapling or the open approach. Although, in a total of 132 patients in four studies, no severe complications occurred, neither laser, nor argon beam nor diathermic cutting really guarantee a sealing of the incised edges from the mediastinum. Accordingly, further research is necessary to identify the ideal candidates for this valuable new procedure of the endoscopic armamentarium.

Competing interests: None.

Figure 1 The inherent problem with free endoluminal dissection is the length of the residual spur: a cut right down to the bottom of the sac opens the mediastinum.

References

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• 2 Gutschow C A, Hamoir M, Rombaux P. et al . Management of pharyngoesophageal (Zenker’s) diverticulum: which technique?.  Ann Thorac Surg. 2002;  74 1677-1683
• 3 Vogelsang A, Preiss C, Neuhaus H, Schumacher B. Endotherapy of Zenker's diverticulum: long-term follow-up using the needle-knife technique.  Endoscopy. 2007;  39 131-136
• 4 Christiaens P, De Roock W, Van Olmen A, Moons V, D'Haens G. Endoscopic treatment of Zenker's diverticulum: results of a single-center series of 21 patients.  Endoscopy. 2007;  39 137-140
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• 6 Costamagna G, Iacopini F, Tringali A, Marchese M, Spada C, Familiari P, Mutignani M, Bella A. Flexible endoscopic Zenker diverticulotomy: cap-assisted vs. diverticuloscope-assisted technique.  Endoscopy. 2007;  39 146-152