Real-time intraoperative functioning lumen imaging probe during endoscopic per-oral pyloromyotomy (pop)

Background Endoscopic per-oral pyloromyotomy (POP) has emerged as a safe and effective first line option in medically refractory gastroparesis. Determining the appropriate extent of the pyloromyotomy continues to present a challenge as there are no standardized tools for measuring changes in pyloric distensibility during the procedure. The objective of this study was to evaluate the utility of using impedance planimetry with endoscopic functional luminal imaging probe (FLIP) to measure changes in pyloric distensibility after POP, and to compare these changes with improvement in symptoms and objective gastric emptying. Methods Patients with medically refractory gastroparesis underwent POP with FLIP measurements of the pylorus (EndoFLIP®, Medtronic, Fridley MN). FLIP measurements, as well as changes in symptoms measured by the validated gastroparesis cardinal symptom index (GCSI) and scintigraphic gastric emptying studies (GES), were evaluated before and after POP. Results A total of 14 patients underwent measurement with FLIP during POP, 12 of whom had pre- and post-POP measurements. Mean pyloric diameter increased by 1.4 mm, from 13.9 mm to 15.3 mm ( p = 0.0012). Mean distensibility index increased from 6.2 mm 2 /mmHg to 9.1 mm 2 /mmHg (p = 0.0074). Successful division of the pylorus was achieved in 100% of patients with a mean operative time of 36 min and no perioperative complications. The mean length of stay was 0.7 days (0–3 days). Post-POP mean GCSI score improved from 2.97 to 2.28 at a mean follow-up time of 27 days ( p < 0.001). Objective improvement in gastric emptying was observed in 80% of patients with scintigraphic GES, with mean four-hour retention decreasing from 46.3% to 32.4% (p < 0.007). Conclusions FLIP is a safe and feasible tool to provide objective measurements during POP. Larger cohorts with longer follow-up are required to determine if measured improvements in pyloric diameter and distensibility are predictive of sustained improvements in GCSI and GES.