Quantification of fluoroscopic fundoplication anatomy: inter- and intraobserver reliability

The etiology of postfundoplication dysphagia remains incompletely understood. Subtle changes of gastroesophageal junction (GEJ) anatomy may be contributory. Barium swallows have potential for standardization to evaluate postsurgical anatomical features. Using structured barium swallows, we aim to identify reproducible, objectively measured postfundoplication anatomical features that will permit future comparison between patients with/without dysphagia. At 6-12 months of postfundoplication, 31 patients underwent structured barium swallow with video-fluoroscopy recording: standing anteroposterior; standing oblique (×2); prone oblique (×2); and prone oblique with continuous free drinking. A primary observer recorded 11 variables of GEJ anatomy for each view, repeated 3 months later, forming two datasets to assess intraobserver consistency. Interobserver reliability was determined using a dataset each from the primary observer and two medical students (after training). Intraclass correlation coefficients (ICC) were based on two-way mixed-effects model (ICC agreement: 0.40-0.59 'fair'; 0.60-0.74 'good'; 0.75-1.00 'excellent'). Interobserver reliability was good-excellent for 47 of 66 measurements. Measures of maximal esophageal diameter cf. wrap opening diameter and posterior esophageal angle showed high interobserver reproducibility on all views (ICC range 0.84-0.91; 0.68-0.80, respectively). Interobserver agreement was good-excellent for 5/6 views when measuring anterior GEJ displacement and axis deviation (ICC range 0.56-0.79; 0.41-0.77, respectively). Measures of wrap length showed lower reproducibility. Prone oblique measurements showed highest reproducibility (good-excellent agreement in 19/22 measurements). Intraobserver consistency was excellent for 98% of measurements (ICC range 0.74-0.99). Objective measurements of postfundoplication GEJ anatomy using structured barium swallow are reproducible and may allow further interrogation of anatomical features contributing to postfundoplication dysphagia.