Development and technique of per oral endoscopic myotomy (POEM) for achalasia

Peroral endoscopic myotomy for treatment of achalasia: from bench to bedside (with video)

BACKGROUND

Peroral endoscopic myotomy (POEM) is a novel approach to performing esophageal myotomy through a long submucosal tunnel.

OBJECTIVE

This study aimed to investigate the feasibility and safety of POEM for treatment of achalasia.

DESIGN

Preclinical animal study and prospective clinical study.

PATIENTS

Consecutive patients diagnosed with achalasia with high-resolution manometry.

INTERVENTIONS

POEM was standardized for preclinical and clinical studies. After submucosal injection, a mucosal incision was made 15 cm above the gastroesophageal junction (GEJ). A long submucosal tunnel was created to extend below the GEJ. The endoscopic myotomy started 10 cm above and extended 2 cm below the GEJ. We first conducted a preclinical animal study to confirm the safety of POEM. POEM was then performed for the treatment of achalasia in humans.

MAIN OUTCOME MEASUREMENTS

Relief from dysphagia assessed by the dysphagia score and Eckhardt score. High-resolution manometry and pH monitoring were performed to evaluate the posttreatment effects and esophageal acid exposure.

RESULTS

Seven 30-kg porcine models underwent POEM in the survival study. All of the pigs survived except 1, which sustained pneumomediastinum. POEM was performed for the treatment of achalasia in 16 patients. The mean operating time was 117.0 ± 34.1 minutes. All patients tolerated food on day 2, with a contrast study confirming no leakage. The median follow-up was 176.5 days (range 98-230 days). The postoperative basal lower esophageal sphincter pressure was significantly reduced (mean reduction, 13.9 ± 14.5 mm Hg; P = .005) and 4-second integrated relaxation pressure of the GEJ (mean reduction, 10.1 ± 7.4 mm Hg; P = .001). Of these patients, 58.3% had a normalized 4-second integrated relaxation pressure, whereas 20% had excessive esophageal acid exposure after the procedure. There was a significant improvement in quality of life 6 months after POEM measured by the Short Form-36 questionnaire.

LIMITATION

Small sample size.

CONCLUSIONS

POEM is a feasible, safe, and effective treatment for achalasia.

Intraoperative assessment of esophagogastric junction distensibility during per oral endoscopic myotomy (POEM) for esophageal motility disorders

BACKGROUND

Per oral endoscopic myotomy (POEM) is a novel treatment for esophageal motility disorders such as achalasia. To date, the extent of the myotomy has been determined based on the subjective assessment of the endoscopist. We hypothesized that the real-time measurement of esophagogastric junction (EGJ) distensibility using a novel functional lumen-imaging probe would enable objective evaluation of POEM.

METHODS

Patients diagnosed with achalasia disorders electively underwent POEM. Using impedance planimetry with a transorally inserted functional lumen-imaging probe (EndoFLIP), cross-sectional areas (CSA) and distensibilities at the EGJ were measured intraoperatively immediately before and after the transoral myotomy (n = 4). All patients completed their 6-month follow-up and two patients had repeat distensibility tests at this time. Four healthy volunteers served as a control group.

RESULTS

POEM was successfully performed in all patients (4/4). Premyotomy measurements (40-ml fill mode) showed a median diameter of 6.5 mm (range = 5.2-7.9 mm) at the narrowest location of the EGJ and was 10.1 mm (7.3-13.2 mm) following POEM. CSA increased from 41.5 mm(2) (20-49 mm(2)) to 86 mm(2) (41-137 mm(2)) at a similar median intraballoon pressure (40.3 vs. 38.6 mmHg). The increased EGJ distensibility (DI, 1.0 vs. 2.4 mm(2)/mmHg) was comparable to that of healthy volunteers (2.7 mm(2)/mmHg).

CONCLUSION

Functional lumen distensibility measures show that POEM can result in an immediate correction of the nonrelaxing lower esophageal sphincter, which appears similar to that of healthy controls. Intraoperative EGJ profiling may be an important tool to objectively guide the needed extent and completeness of the myotomy during POEM.