Defining the force-injury profile for retrieval of esophageal button batteries: an ex vivo porcine model.

INTRODUCTION: Treatment of button battery (BB) ingestion requires rapid removal to limit injury. Preliminary data demonstrate the rapidity with which injury occurs, but nevertheless rapid extraction is often delayed by transfer. Uncertainty regarding the concern for perforation and mechanical consequences of acute esophageal injury during retrieval remain poorly defined and contribute to low rates of early intervention. We developed a BB extraction model in cadaveric porcine esophagus to measure the force-injury relationship. METHODS: Our model was developed to address 3 questions: 1) following BB ingestion, what is the time to injury? 2) what BB removal force is needed for esophageal injury? 3) in injured esophagus, what force is needed to remove a BB? Descriptive statistics were tabulated, and continuous variables were compared with t-tests. RESULTS: Mucosal injury began within 21 minutes of BB exposure. In an ex vivo stricture model, injury occurred with 8.99 ± 3.30 lbs of force at 30 minutes, 4.99 ± 0.53 lbs at 60 minutes and 1.18 ± 0.51 lbs at 120 minutes, which was less than the 11.68 ± 1.48 lbs required to injure native esophagus (p<.001). At matching time points, it took between 0.14 to 0.18 lbs of force for BB extraction. CONCLUSIONS: Using an ex vivo BB extraction model, we define the force-injury profile after esophageal BB exposure. Notably, force required to injure esophagus after 1 hour of exposure is half that required in native esophagus, but still 30 times more than the maximal force to extract a BB. This difference suggests a robust factor of safety present when removing esophageal foreign bodies.