POEM endoscopic treatment of achalasia using the EndoFLIP® (Endolumenal Functional Lumen Imaging Probe) imaging system
Epublication WebSurg.com, Jun 2013;13(06). URL: http://websurg.com/doi/vd01en3970
This is the case of a 75-year-old lady who presented with recurrent symptoms of dysphagia and regurgitation associated with a significant weight loss due to recurrent achalasia. She developed progressive recurrence after a first surgical treatment by an open Heller myotomy and Dor fundoplication back in 1974. This first operation was complicated by an esophageal perforation which required a thoracotomy to be controlled. Several dilatations were attempted with no significant symptoms improvement. One of the most important aspects of POEM is to ensure that the submucosal tunnel adequately extends into the gastric cardia in order to perform a complete and adequate myotomy. To this aim, proper orientation is key but may be difficult even to the experienced eye of the interventional endoscopist familiar with ESD techniques and dissection planes. Six endoscopic cues that assist with this determination have been identified so far. The most useful cue was deemed to be the characteristic appearance of the submucosal space of the cardia of a slightly different color with a somewhat yellowish hue, more capacious than the esophageal submucosal space with more and larger vessels. Identification of the thick, cord-like circular muscle fibers of the lower esophageal sphincter was deemed as the second most useful cue, and noting a bluish coloration of the cardial mucosa from the colored submucosal injection via a retroflexed luminal view was the third most useful cue. Endoscope insertion length within the submucosal tunnel and the palisading mucosal vessels marking the gastroesophageal junction and visible also from inside the submucosal tunnel were deemed helpful but to a lesser degree. Nevertheless, identification of these endoscopic landmarks is not easy nor always reproducible. Creation of the submucosal tunnel is very sensitive to case difficulty and accounts for the large fluctuations in procedure time. Another area of technique variability involves the orientation of the myotomy. In order to improve the recognition of the essential landmarks, we developed a myotomy technique guided by the EndoFLIP® catheter. EndoFLIP® is a unique physiology test that uses both volumetric assessment and pressure readings to calculate compliance and high pressure zones as well as distensibility changes at the gastroesophageal junction. It allows intraoperative assessment of myotomy completion. The use of this device provides a direct immediate feedback with regards to the efficacy of the myotomy. The EndoFLIP® catheter used in this case (EF-325L) has been specifically modified for the POEM procedure. It differs from the standard EndoFLIP® catheter in that it contains an integrated illuminating LED adjacent to the centre measurement electrode. When the catheter is positioned intraluminally at the gastroesophageal junction and secured to this position taping the distal end to the endothracheal tube, it allows to direct dissection towards the cardia.