Influence of Pyelocaliceal Anatomy on the Success of Flexible Ureteroscopic Approach

Introduction: Some particularities of pyelocaliceal anatomy are described to influence the success rate of flexible ureteroscopy. The aim of this study was to evaluate the correlation between anatomy (infundibulopelvic angle, length of the inferior caliceal infundibulum) and the success of flexible ureteroscopic approach of lower calyx. Materials and Methods: We studied 47 patients in whom flexible ureteroscopic procedures were performed between October 2002 and October 2006: 43 cases with inferior caliceal calculi or multiple caliceal (including the inferior calyx) lithiasis and 4 patients with inferior calyx diverticulae and intradiverticular lithiasis. In patients with multiple caliceal calculi, we only evaluated the success of flexible ureteroscopic approach of the inferior caliceal ones. Infundibulopelvic angle was wider than 90o in 8 cases, ranged between 30 degrees and 90o in 35 cases, and was smaller than 30 degrees in 4 cases. Results: The success rate was 87.5% (7/8 patients) in patients with infundibulopelvic angle wider than 90 degrees, 74.3 % (26/35 patients) when this angle ranged between 30 degrees and 90 degrees, and 0 % (0/4 patients) in patients with infundibulopelvic angle smaller than 30 degrees. In patients with infundibulopelvic angle between 30 degrees and 90 degrees, the success rate was 88.2% when the length of the inferior caliceal infundibulum was shorter than 3 cm and only 61.1% when it was longer. Conclusions: Pyelocaliceal anatomy influences the performances of flexible ureteroscopy. This parameter, lesion location (stone or tumor) and the influence of accessory instruments on flexible ureteroscope's deflection should be evaluated before recommending flexible ureteroscopic approach.