Shear Stress in the Performance of Esophageal Dilation: Comparison of Balloon Dilation and Bougienage

Abstract
While both the balloon catheter and the bougie are effective for esophageal dilation, each has its proponents. From a biomechanical point of view, the two methods should differ significantly, since bougienage depends on advancing a tapered dilator to generate radial force and balloon catheter dilation depends solely on balloon inflation to generate its radial dilating force. In a series of equivalent esophageal stenoses made by suture plication in swine esophageal segments, the authors measured shear force and radial force generated by dilation with a Maloney bougie, a Savary-Gilliard bougie, and a esophageal balloon. The mean radial forces generated were 6.42, 4.46, and 4.04 N, respectively, which did not differ significantly. However, the mean shear forces measured were 16.92, 6.92, and 1.44 N, respectively. The shear force with the Maloney bougie differed significantly from that with Savary-Gillard and the balloon and was on the same order of magnitude as the tensile strength of the esophagus (25-27 N). The shear force with the balloon was significantly lower than that with either bougie. In theory, the reduced shear force associated with balloon dilation might reduce the risk of esophageal perforation, but safely will have to be determined in clinical trials.