Complications of Percutaneous Nephrolithotomy Classified by the Modified Clavien Grading System: A Single Center's Experience over 16 Years

Purpose: To stratify complications of percutaneous nephrolithotomy (PCNL) in a single, tertiary hospital by use of the modified Clavien system. Materials and Methods: From May 1987 to December 2010, 1,236 cases of PCNL were performed at our institute. Medical records were available for 826 cases of PCNL from 698 patients, from February 1995 to December 2010. Using multiple factors, we retrospectively reviewed and analyzed 698 patients for complication rates classified by the modified Clavien grading system, along with success rates.\ Results: In 698 patients, staghorn stone patients accounted for 33.8% (236 patients). Initial and overall stone-free rates were 69.9% and 88.8%. A total of 297 complications were documented in 282 patients. According to the modified Clavien classification, grade I, II, IIIa, IIIb, IVa, IVb, and V complications were observed in 88 (12.6%), 145 (20.8%), 31 (4.4%), 5 (0.7%), 6 (0.9%), 4 (0.6%), and 3 (0.4%) patients, respectively. Transient peri-nephrostomy catheter urine leakage (15.2%) was the most common complication, followed by transient fever > 38o (11%) and transfusion (6.9%). Other individual complications occurred in less than 1.5% of cases. In patients with staghorn stones, grade I, II, IIIb, and IVa complications were significantly more common, and all grade IVb and V complications occurred in patients with staghorn stones. Conclusions: The modified Clavien classification provides a standardized grading system for complications of PCNL, although consensus on specific complications would prompt better comparison between centers. A shorter operation time is imperative to achieve less bleeding. Previous stone-related fever and staghorn stones are significant contributing factors for developing postoperative fever.