423 Blown out Myotomy (BOM), a Complication Following Laparoscopic Heller Myotomy and Per-Oral Endoscopic Myotomy

Abstract

INTRODUCTION: Achalasia results from a failure of lower esophageal sphincter relaxation and an absence of normal peristalsis. Achalasia is diagnosed by High-Resolution Manometry (HRM) and can be treated with Laparoscopic Heller Myotomy (LHM) or Per-oral Endoscopic Myotomy (POEM). LHM and POEM are highly effective with more than 90% clinical efficacy reported in the literature. Although success rates are encouraging, patients may experience complications and recurrent symptoms. We identified patients, status post LHM or POEM, who had a BOM, a pseudodiverticulum at the prior myotomy site, on follow-up. Our aim was to assess what factors are associated with a BOM and how this affects patient reported outcomes. METHODS: We retrospectively identified patients from the Northwestern Esophageal Center Achalasia Natural History Study undergoing HRM between 1/2015 and 10/2017, following LHM or POEM, as therapy for achalasia. Patients must have also had a post-treatment esophagram within 1 year of HRM. A BOM was defined radiographically as a wide-mouthed outpouching (>50% increase in esophageal diameter) in the area of the prior myotomy (Image). RESULTS: 129 consecutive patients were identified; demographics are in Table 1. A BOM was identified in 17.8% of patients. Comparing patients with a BOM to those without, initial achalasia subtypes were overall different (P = 0.004), type III achalasia specifically was more common (39.1% vs. 14.2%, P = 0.014), and LHM was more common than POEM (73.9% vs. 26.1%, P = 0.013), respectively (Table). Anterior vs. posterior approach for POEM and wrap type (Nissen, Dor, Toupet), when LHM was performed, were not predictors of BOM occurrence. Multiple treatments (prior LHM, POEM or pneumatic dilation) was not associated with an increased risk of BOM formation. The Integrated Relaxation Pressure (IRP) was significantly higher in patients with BOM compared to those without (15.0 mmHg vs. 11.0 mmHg, P = 0.025). Eckardt Scores (ES) were significantly higher, both statistically and clinically, in patients with BOM (5 vs. 2, P = 0.002). CONCLUSION: Our analysis suggests that an esophageal myotomy to treat spastic achalasia, treatment with LHM, and a higher post-treatment IRP are more common in patients with a BOM. These findings suggest that increased wall strain, whether it be from residual spastic contractility, continued outflow obstruction from fundoplication, or an incomplete myotomy, may be the underlying mechanism of failure.