Tips and tricks for avoiding the dreaded intramural esophageal dissection during peroral endoscopic myotomy: recognize!

Peroral endoscopic myotomy (POEM) has been shown to be safe and effective for the management of achalasia and esophageal spastic disorders [1]. Nonetheless, it is noteworthy that POEM is a complex procedure with a steep learning curve and the potential for serious adverse events [2].

In a recent issue of Endoscopy, Ye et al. reported a case of intramural esophageal dissection during POEM [3]. The authors performed the initial mucosal incision following injection of saline with methylene blue. Tunnel creation was challenging as the “submucosal” space could not be adequately expanded and separated from the mucosa, and its endoscopic appearance was deemed unusual. After further assessment, the authors were able to conclude that the previously suspected “submucosal” space was actually the dissected plane between the mucosa and the muscularis mucosae. Injection into the deeper plane allowed expansion of the true submucosal space and permitted completion of the submucosal tunnel and myotomy. After mucosal incision closure, there was no unexpected mucosal breach and the patient was discharged after a short hospital stay.

We take this opportunity to share some practical considerations, based on our own experience when performing POEM, regarding how to minimize the risk of injecting into the wrong plane and inadvertent intramural dissection. Patients with long-standing achalasia often have an unusually thickened esophageal wall. Superficial needle insertion and injection can inadvertently cause separation of the superficial planes, which can be confounded after mucosal incision by the visualized thickened muscularis mucosa mimicking the deeper muscularis propria. To prevent superficial injection, we recommend deep insertion of the needle followed by slow withdrawal of the tip with simultaneous injection. Rapid formation of a bleb with tenting of the mucosa towards the lumen suggests that expansion of the submucosal space has been achieved. A slow rise of the bleb or significant resistance during injection should raise the suspicion that the tip of the needle is not in the submucosa. Furthermore, we recommend the use of a nonviscous solution for this initial lift, as inadvertent injection of a viscous solution can more readily dissect the plane between the mucosa and muscularis mucosae. As noted in this case report, the inability to adequately expand the tunnel with repeated injections should also raise the suspicion that intramural dissection has occurred. The presence of multiple superficial branching vessels and nonstaining of the tunnel with injection can be other tell-tale signs. In our experience, and as shown by Ye et al., access to the true submucosal space can be achieved by re-injection into the deeper plane. However, access to the submucosa should be attempted a few centimeters below the initial mucosal incision, in order to reduce the risk of a full breach at the same level.

In summary, intramural esophageal dissection during POEM is probably a relatively rare event, yet early recognition is key in preventing serious adverse events. With the ongoing maturation of POEM, we will continue to gain further insight and experience on the technical intricacies associated with this procedure.

• References

• 1 Akintoye E, Kumar N, Obaitan I. et al. Peroral endoscopic myotomy: a meta-analysis. Endoscopy 2016; 48: 1059-1068
• 2 Yang D, Draganov PV. Expanding role of third space endoscopy in the management of esophageal diseases. Curr Treat Options Gastroenterol 2018; 16: 41-57
• 3 Ye L, Jian J, Ngamruengphong S. et al. Intramural esophageal dissection during peroral endoscopic myotomy. Endoscopy 2019; DOI: 10.1055/a-0875-3869.