Conclusion  The current construction of the catheter and software analysis used in high-resolution manometry do not allow precise measurement of LES length. Errors in the identification of the upper border of the sphincter may compromise accurate positioning of a pH probe. Content Type Journal ArticleCategory 2009 SSAT Poster PresentationDOI 10.1007/s11605-009-1042-0Authors Shahin Ayazi, University of Southern California Division of Thoracic and Foregut Surgery, Department of Surgery, Keck School of Medicine 1510 San Pablo Street, Suite 514 Los Angeles CA USAJeffrey A. Hagen, University of Southern California Division of Thoracic and Foregut Surgery, Department of Surgery, Keck School of Medicine 1510 San Pablo Street, Suite 514 Los Angeles CA USAJoerg Zehetner, Univer...