Effect of Simple Malrotation on Percutaneous Nephrolithotomy: A Matched Pair Multicenter Analysis

Abstract

Purpose: In this multicenter study we compared the outcome of percutaneous nephrolithotomy in patients with and without malrotated kidneys. Materials and Methods: A total of 44 patients (group 1) at 6 institutions who underwent percutaneous nephrolithotomy for kidneys with simple malrotation were enrolled in our study. Attending physicians in our group also provided the same number of cases of percutaneous nephrolithotomy done for nonmalrotated (normal) kidneys (group 2). Group 2 patients were selected by match pairing. Operative and postoperative data on the 2 groups were compared using the chi-square, Student t and Fisher exact tests. Results: As a result of match pairing, the 2 groups were similar in age, gender, body mass index, and stone size and site. Mean +/- SD stone size was 5.9 +/- 3.5 cm(2) in group 1. Multiple access attempts were required in 9 (20.5%) and 7 cases (15.9%) in groups 1 and 2, respectively (p > 0.05). Mean fluoroscopy time was 7.0 +/- 3.9 minutes in the malrotated kidney group and 7.3 +/- 4.5 minutes in the nonmalrotated kidney group (p > 0.05). The mean hemoglobin decrease after percutaneous nephrolithotomy was significantly higher in group 1 (-1.9 vs -1.3 gm/dl, p = 0.008) but the blood transfusion rate was similar in the 2 groups. The procedure success rate in groups 1 and 2 was 77.3% and 79.5%, respectively (p > 0.05). Conclusions: Percutaneous nephrolithotomy is safe and effective even in patients with larger kidney stones and malrotated kidneys.