Clinical utility of cricopharyngeal distensibility measurements during endoscopic myotomy for Zenker’s diverticulum

Background and Aims: Flexible endoscopic cricopharyngeal myotomy (FECM) allows minimally invasive treatment of patients with Zenker's diverticulum (ZD); however, retreatment rates are substantial. We hypothesized that the functional lumen imaging probe (FLIP) may provide insight into ZD pathophysiology and serve as an intraprocedural guide to adequacy of myotomy.Methods: We prospectively evaluated 11 ZD patients undergoing FECM and compared the baseline cricopharyngeal (CP) distensibility with 16 control subjects. Intraprocedural CP distensibility was measured immediately pre- and postmyotomy. The CP distensibility index (CP-DI) was defined as a ratio of the narrowest cross-sectional area (nCSA) and the corresponding intrabag pressure at 40 mL distension. Same-procedure myotomy extension was undertaken in a subgroup if threshold distensibility changes were not met.Results: ZD patients had reduced baseline nCSA and CP-DI compared with control subjects, (169.6 vs 227.5 mm(2) [P < .001] and 3.8 vs 7.6 mm(2)/mm Hg [P <.001], respectively). After CP myotomy, both nCSA and CP-DI increased significantly by an average of 74.2 mm(2) (95% confidence interval [CI], 35.1-113.3; P = .002) and 2.2 mm(2)/mm Hg (95% CI, .6-3.8; P = .01), respectively. In the subgroup with no significant change in CP distensibility after initial myotomy (n = 6), myotomy extension resulted in significant increases in both mean nCSA and CP-DI of 66.6 mm(2) (95% CI, 16.4-116.8; P = .03) and 1.9 mm(2)/mm Hg (95% CI, .4-3.3; P = .015), respectively. There were no adverse events.Conclusions: CP distensibility is reduced in ZD patients and is partially reversible by FECM. An intraprocedural FLIP CP distensibility measurement is safe and sensitive in detecting myotomy-induced changes. These findings support using FLIP to optimize FECM outcome. Further studies are required to derive precise metrics predictive of clinical response.