Complications of percutaneous nephrolithotomy classified by the modified clavien grading system: a single center's experience over 18 months.

Introduction: There is still no consensus on how to define and grade postoperative complications, and this hampers comparison of outcome data among different centers. A classification (modified Clavien system) has recently been proposed for this purpose, and we reviewed our experience with percutaneous nephrolithotomy (PCNL), grading perioperative complications according to this new classification. Materials and methods: A total of 976 PCNLs were performed for reno-ureteral lithiasis between January 2012 and July 2013 in our clinic, and charts were retrospectively reviewed focusing on complications observed. Complications were evaluated and stratified into five grades by the modified Clavien classification system. Results: PCNL was performed in 141 cases (14.44%), ureteroscopy followed by PCNL in 23 cases (2.35%) and tubeless PCNL (double J stent) in 812 cases (83.19%). The average stone volume was 7.9 ± 3.9 cm². A total of 322 complications were documented in 291 patients (29.81%). According to the modified Clavien classification, grade 1, 2, 3a, 3b, 4a, 4b, and 5 complications were observed in 92 (9.42%), 137 (14.03%), 51 (5.22%), 31 (3.17%), 6 (0.61%), 5 (0.51%), and 0 patients, respectively. The majority of complications were related to bleeding, urine leakage and infections. The stone free rate achieved at 3 months postoperative was 87.8% - 857 patients. Conclusions: The majority of complications after PCNL are minor. The modified Clavien classification provides a standardized grading system for complications of PCNL, although consensus on specific complications would prompt better comparison between centers. We recommend this graded classification scheme to apply to other surgical procedure. [ABSTRACT FROM AUTHOR]