RESUMEN
OBJECTIVES: A classification (modified Clavien system) has been proposed to grade perioperative complications. We reviewed our experience with percutaneous nephrolithotomy (PNL), grading the complications according to this new classification. METHODS: A total of 811 PNLs were performed between 2003 and 2006, and charts were retrospectively reviewed focusing on complications observed. According to the modified Clavien classification system, perioperative complications were stratified into five grades. Grade 1 defined all events that, if left untreated, would have a spontaneous resolution or needed a simple bedside intervention. Grade 2 complications required specific medication, including antibiotics and blood transfusion. Grade 3 complications necessitated surgical, endoscopic, or radiologic intervention (3a without general anesthesia, 3b under general anesthesia). Neighboring organ injuries and organ failures were classified as grade 4, and death was considered a grade 5 complication. Kidney stones treated with PNL were also classified as simple and complex and complication rates were compared. RESULTS: A total of 255 perioperative complications were observed in 237 (29.2%) patients. There were 33 grade 1 (4%), 132 grade 2 (16.3%), 54 grade 3a (6.6%), 23 grade 3b (2.8%), 9 grade 4a (1.1%), and 3 grade 4b (0.3%) complications, and 1 death (0.1%). Most complications were related to bleeding and urine leakage. Grade 2 and 3a complications were significantly more common in patients with complex renal stones. CONCLUSIONS: A graded classification scheme for reporting the complications of PNL may be useful for monitoring and reporting outcomes. However, minor modifications concerning auxiliary treatments are needed and further studies are awaited.