Retrograde ureteropyeloscopy for lower pole caliceal calculi

Purpose: Contemporary treatment of lower pole renal calculi includes extrac orporeal shock wave lithotripsy, percutaneous nephrostolithotomy and retrog rade ureteropyeloscopy. Success rates for shock wave lithotripsy are reduce d in this setting, especially for stones greater than 1 cm. and/or in patie nts with anatomical variants. Percutaneous treatment, although effective, s ubjects the patient to increased morbidity. We studied the safely and effic acy of retrograde ureteroscopic treatment of lower pole intrarenal calculi. Materials and Methods: We evaluated 90 stone burdens localized to the lower pole and treated with a small diameter, actively deflectable, flexible ure teropyeloscope and a 200 mu, holmium laser fiber. Stone burdens were classi fied as group 1-10 or less,group 2-11 to 20 and group 3-greater than 20 mm. in largest diameter. Patients with calculi less than 2.5 cm. were treated as outpatients unless concurrent medical conditions required hospitalizatio n. Larger stones and partial staghorn calculi (group 3) frequently required 2-stage endoscopic procedures with retrograde intrarenal irrigation for 36 hours to clear debris. An acceptable immediate surgical outcome was define d as complete fragmentation reducing the stone burden to dust and 2 mm. or less fragments. Success was defined as clear imaging (that is stone-free) o n renal sonography with minimum 3-month followup. Extreme anatomical varian ts, including a long infundibulum, acute infundibulopelvic angle and a dila ted collecting system, were noted and correlated with surgical failures. Results: Endoscopic access and complete stone fragmentation were achieved i n 94, 95 and 45% of groups 1, 2 and 3, respectively. After a second treatme nt the success rate increased to 82% in group 3, with an overall rate of 91 %; Of the 19 surgical failures 8 were secondary to inability to access the lower pole and 11 were secondary to inability to render the patient stone-f ree. In 2 of the 19 cases infundibular strictures hindered ureteroscopic ac cess. In addition, of the anatomical variants a long lower pole infundibulu m was the most statistically significant predictor of failure. Mean operati ve time ranged from 38 minutes for small to 126 for the largest calculi. Th ere were no major complications. Overall stone-free rates with minimum 3-mo nth followup were 82, 71 and 65% in groups 1, 2 and 3, respectively, and 88 , 77 and 81%, respectively, in patients with an acceptable initial surgical outcome(that is excluding those with access failures from analysis). Conclusions: Retrograde ureteropyeloscopy is a safe and effective surgical treatment for lower pole intrarenal calculi.