Per oral endoscopic myotomy (POEM) for all spastic esophageal disorders?

Achalasia is a rare esophageal motility disorder defined as impaired relaxation of the esophagogastric junction (EGJ) and the absence of esophageal peristaltic contractions. High resolution manometry (HRM) is now the gold standard for the diagnosis of achalasia. Pandolfino et al. proposed classifying achalasia into three subtypes based on esophageal contraction patterns on HRM [1]. In the most recent iteration (version 3.0) of the Chicago Classification of esophageal motility disorders on HRM, achalasia is defined as impaired EGJ relaxation and subsequently divided into three subtypes [2]. Type I is characterized by the absence of esophageal contractions and the absence of pressurization, type II by the absence of esophageal contractions and at least 20% of swallows that are associated with panesophageal pressurization, and type III (also called spastic) by at least 20% of contractions that are premature (●" Fig.1a– c). Different studies demonstrated the clinical relevance of this classification [3–6]. Thus, patients with type II achalasia had the best outcome overall after treatment, whereas patients with type III had the worst. The response to treatment may also differ according to the performed procedure. Rohof et al. observed that outcome was better in patients with type III achalasia who underwent laparoscopic Heller myotomy (LHM) than in those who underwent pneumatic dilation [5]. One simple explanation would be that pneumatic dilation alleviates only EGJ obstruction, whereas LHM not only alleviates EGJ obstruction but also may treat spastic contractions (which are associated with EGJ obstruction in type III achalasia) by extending the myotomy along the distal esophagus. The popularity of per oral endoscopic myotomy (POEM) for the treatment of achalasia is rapidly growing. First described in 1980 by Ortega et al. [7], the procedure was developed later by Inoue et al., who used the submucosal flap technique as a safe transmural approach [8]. Since 2010, different series have reported the safety and efficacy of the procedure [9–13]. In this issue of Endoscopy International Open, Kumbhari et al. have evaluated the efficacy of the POEM procedure in 49 patients with type III achalasia [14]. Patients at eight different centers were retrospectively included, and their results were compared with those of 26 patients who underwent LHM at a single center. A clinical response, defined as an Eckhardt score of 1 or lower, was more frequently observed in the patients treated with POEM than in those treated with LHM (98.0% vs. 80.8%; P<0.01). As demonstrated by Kumbari et al., POEMmay be an attractive procedure for patients with type III achalasia. The fact that endoscopic myotomy can be startedmore than 10cm above the EGJ may explain why it may be more efficient for treating type III achalasia, which is associated with abnormal contractions in the mid and distal esophagus. However, the results of this retrospective study must be interpreted with caution because the endoscopic myotomy technique probably varied from one center to another. Thus, the effect of the exact length of the myotomy, and the effect of a myotomy limited to the internal muscular layer versus that of a full-thickness myotomy, cannot be correctly evaluated based on these results. When HRM is used, hypercontractile esophageal motility disorders are classified into two categories: distal esophageal spasm (DES), in which at least 20% of contractions are premature (contractions occurring within a phase when esophageal contractile activity is normally inhibited), and jackhammer esophagus, in which at least 20% of contractions occur with extreme vigor (contractions with a distal contractile integral>8000 mmHg.s.cm) [2] (●" Fig.1d,e). These disorders, never encountered in normal individuals, are responsible for esophageal symptoms (mainly dysphagia and chest pain) [15,16].