Inferior Pelvicalyceal Anatomy – An Important Determinant of Residual Stone Clearance after Shock Wave Lithotripsy.

ABSTRACT

Background: Shock wave lithotripsy (SWL) has revolutionized the treatment of renal stones. Clearance of stones after SWL depends upon a multitude of factors. The purpose of this study was to evaluate the effect of inferior calyceal anatomy on the stone clearance after SWL for renal stones. Methods: The study included a total 52 patients with age between 21 and 81 years admitted in our hospital with renal stones who were treated with SWL. The factors studied were- Infundibulo-pelvic angle (IPA), Infundibular length (IL), Infundibular width (IW) and their affect on stone clearance. Results: In the lower caliceal system three factors for stone clearance were studied; patients with an infundibulo-pelvic angle (IPA) of more than 89.3 degree had a statistically significant clearance as compared an angle less than that ( p=0.0000 ; 95% confidence interval [CI] , 0.774 to 1.1036 ); patients with an infundibular length (IL) of less than 26mm had a statistically significant clearance ( p=0.0004; 95% confidence interval [CI] , 0.616 to 0.0945 ); the infundibular width did not have a significant role in stone clearance in our study. Conclusion: In the lower calyceal system, the infundibulo-pelvic angle (IPA) and the infundibular length (IL) play a significant role in stone clearance.