Factors affecting outcomes of percutaneous nephrolithotomy in horseshoe kidneys

To analyze the patient- and procedure-related factors affecting the outcomes of percutaneous nephrolithotomy (PNL) in horseshoe kidneys (HSKs).

A retrospective analysis was done of patients with stones in HSKs treated with PNL in 3 referral centers between 1998 and 2013. Demographics, along with perioperative characteristics, were evaluated in detail as to whether or not they had an effect on the success and complication rates.

A total of 54 HSKs with calculi in 53 patients were treated with PNL. Mean stone size was 28.4 ± 19.6 mm (range, 10-120 mm). Fifty-three patients were treated through a single tract, and 1 patient required additional access. Access was directed to the upper calyx (n = 27), middle calyx (n = 17), and lower calyx (n = 10) through the intercostal (n = 23) and subcostal (n = 31) areas. Flexible nephroscopy was used in 18.5% of the procedures. Postoperative complications were observed in 9 (16.7%) of the procedures. Success rate was 66.7% after a single session of PNL and increased to 90.7% with additional treatments. Although patient demographics, preoperative imaging, and other operative measures did not have significant effect on the complication rate, stone complexity and multiplicity, in combination with flexible nephroscopy, were found to significantly affect the success rate (P = .026, P = .043, and P = .021, respectively). However, in multivariate analysis stone multiplicity was the only factor that affected success rate (P = .004).

Stone parameters play an important role in achieving stone-free status in HSKs. Use of flexible nephroscopy positively affects the success rate by allowing reaching the peripherally located calices.