Outcomes of anterior myotomy versus posterior myotomy during POEM: a randomized pilot study

Background and study aims Peroral endoscopic myotomy (POEM) can be performed via an anterior or posterior approach, depending on the operator's preference. Data are lacking on comparative outcomes of both approaches. Patients and methods This is a pilot randomized study comparing endoscopic anterior and posterior myotomy during POEM in patients with Achalasia cardia (AC). Patients were randomized into 2 groups (n=30 in each group); anterior myotomy group (AG) and posterior myotomy group (PG) and were followed at 1, 3 and 6 months after POEM. Results Technical success was achieved in 100% of cases in both groups and total operative time was comparable (AG-6517.65 minutes versus PG-61.2 +/- 16.67; P =0.38); Mucosotomies were more frequent in AG (20% vs 3.3%; P =0.02). Difference in other perioperative adverse events (AE) including insufflation-related AE and bleeding in both groups were statistically insignificant. At 1-month follow-up Eckardt score AG 0.57 +/- 0.56 vs PG 0.53 +/- 0.71; ( P =0.81), mean LES pressure AG 11.93 +/- 6.36 vs PG 11.77 +/- 6.61; ( P =0.59) and esophageal emptying on timed barium swallow at 5 minutes AG 1.32 +/- 1.08cm vs PG 1.29 +/- 0.79cm; ( P =0.09) were comparable in both groups. At 3 months, Eckardt score (0.52 +/- 0.59 vs 0.63 +/- 0.62; P =0.51) was similar in both groups. Incidence of esophagitis on EGD was comparable in both groups (24% vs 33.3%; P =0.45), however, pH metry at 3 months showed significantly more esophageal acid exposure in posterior group (2.98%+/- 4.24 vs 13.99%+/- 14.48; P <0.01). At 6 months clinical efficacy and LES pressures were comparable in both groups. Conclusion Anterior and posterior approaches to POEM seem to have equal efficacy. However, the occurrence of mucosotomies was higher in the anterior myotomy group and acid exposure was higher with the posterior myotomy approach during POEM.