COMMENTARY

Peroral Endoscopic Myotomy for the Treatment of Achalasia

H. Alejandro Rodriguez-Garcia, MD; Monica T. Young, MD; Hope T. Jackson, MD; Brant K. Oelschlager, MD

Disclosures

March 29, 2017

Surgical Therapy for Achalasia

Myotomy of the lower esophageal sphincter has been the mainstay of surgical treatment of achalasia for over a century. The technique, originally described by Ernst Heller in 1913, consisted of posterior and anterior myotomy performed through a thoracotomy. The procedure evolved over time, with the posterior myotomy abandoned soon after and an abdominal approach in conjunction with a partial fundoplication (Dor or Toupet) favored in the latter half of the 20th century.[1]

The early 1990s saw the adoption of minimally invasive techniques for the Heller myotomy.[2] Although initially popular, the thoracoscopic approach was found to increase postoperative dysphagia rates compared with laparoscopy. This approach also was limited by less extension of the myotomy onto the stomach, a critical step for successful outcomes.[3]

Advances in minimally invasive and endoscopic therapies led to the development of POEM as a recent innovation in the surgical management of achalasia. This procedure was introduced in 2009 by Haruhiro Inoue, who used endoscopic submucosal dissection to create a technique where a submucosal tunnel is developed from the lower esophagus to the stomach, providing a plane where myotomy can be performed.[4] In contrast to other types of natural orifice transluminal endoscopic surgery, POEM has been adopted in many centers across the world, with 1112 cases recently documented in a systematic review.[5]

As an alternative to the Heller myotomy, POEM can serve as the primary intervention in most patients with achalasia, including children.

Contraindications to the procedure include coagulopathy, portal hypertension, and previous surgical interventions in the area that the myotomy will be performed (eg, esophageal ablation or resection).[6]

Outcomes With POEM

The available literature suggests that the short-term success rate for POEM is around 90%.[6,7,8,9] Although the criteria for "success" usually vary from study to study, nearly all POEM series have used the Eckardt score[10] (Table) to assess outcomes.

Table. The Eckardt Score

Score Weight Loss Dysphagia Chest Pain Regurgitation
0 None None None None
1 < 5 kg Occasional Occasional Occasional
2 5-10 kg Daily Daily Daily
3 > 10 kg Every meal Every meal Every meal

The use of this system complicates making direct comparisons with outcomes after laparoscopic Heller myotomy, because the Eckardt score was not widely used in the pre-POEM era. Given its recent introduction, data on long-term outcomes are lacking.

To date, only Inoue and colleagues[11] have reported on long-term outcomes with POEM. In a study describing their first 500 cases, among which long-term data were available for 61 patients, they reported no difference in median Eckardt scores or lower esophageal sphincter pressure after comparing 2-month and 3-year outcomes, suggesting the procedure's medium-term durability.[11]

The most common critique of POEM is that not performing an antireflux procedure may result in an increased risk for postoperative gastroesophageal reflux disease (GERD). Advocates of POEM have argued that some antireflux protection might be afforded by avoiding division of the esophageal longitudinal fibers and the gastric sling fibers, as well as preservation of the phrenoesophageal membrane.[7,12] However, data have shown subjective GERD in 21%-44% of patients and objective evidence of GERD (endoscopy/pH tracing) in 45%-55%[8,11,12,13]—a rate significantly greater than that in most published series of laparoscopic Heller myotomy (LHM) with fundoplication.

POEM vs Heller Myotomy

Currently, there are no published randomized trials comparing POEM with Heller myotomy. A few studies have compared both procedures, although most have consisted of POEM series matched to historic LHM cohorts.

In one such study, Chan and colleagues[14] reported on a series of 33 patients who underwent POEM and were compared with 23 patients treated by LHM. Operative time, blood loss, and pain were lower in the POEM group. Symptom improvement and subjective GERD rates were similar in both groups. Of note, duration of follow-up was much higher in the LHM group (6 vs 60 months).

Similarly, Kumagai and coworkers[15] matched 41 POEM patients to a historic 42-patient LHM cohort. Mean operative time was higher for POEM (100 vs 120 minutes), and postoperative morbidity was similar in both groups. Although the gastroesophageal reflux rates were similar in both groups, it must be noted that only subjective gastroesophageal reflux was documented in the POEM group, whereas in the LHM group, reflux was diagnosed by 24-hour pH testing.

In a prospective study, Teitelbaum and colleagues[9] compared POEM with LHM, with a main outcome measure of timed barium esophagography column height. No significant differences were found in postoperative column height. Postoperative reflux was assessed through patient questionnaires, and subjective evidence of gastroesophageal reflux was found in 31% of patients who had LHM and 17% of those who had POEM (P nonsignificant). Again, these data are somewhat confounded by the fact that the interval to reported symptom scores was significantly higher in the LHM group (43 vs 9 months).

There are considerable gaps in knowledge when comparing POEM with LHM. Thus, the decision to undergo POEM should come after thorough discussion with the patient, who should be counseled on available outcomes data, including the possibility of need for continuing acid-suppression therapy.

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