JOURNAL CLUB: Gastric Band Slippage: A Case-Controlled Study Comparing New and Old Radiographic Signs of This Important Surgical Complication

OBJECTIVE. The purpose of this study was to compare the diagnostic performance of four radiographic signs of gastric band slippage: abnormal phi angle, the “O sign,” inferior displacement of the superolateral gastric band margin, and presence of an air-fluid level above the gastric band. MATERIALS AND METHODS. A search of the electronic medical record identified 21 patients with a surgically proven slipped gastric band and 63 randomly-selected asymptomatic gastric band patients who had undergone barium swallow studies. These studies were evaluated for the four signs of band slippage by two independent radiologists who were blinded to clinical data. Sensitivity, specificity, and positive and negative predictive values were calculated for each radiographic sign of band slippage. Interobserver agreement between radiologists was assessed using the Fleiss kappa statistic. RESULTS. In evaluating for gastric band slippage, an abnormal phi angle greater than 58° was 91–95% sensitive and 52–62% specific (κ = 0.78)...