Study of predictive factors for complications after percutaneous nephrolithotomy according to the Clavien classification.

OBJECTIVE: Set predictors of complications in percutaneous nephrolithotomy (PCNL) using the modified Clavien system.

MATERIAL AND METHODS: Retrospective study included 172 PCNL in Galdakao position made in the La Ribera Hospital between January 2005 and December 2011. They classified the complications of these procedures using the modified Clavien system. We performed a univariate analysis (Chi(2) Test and Cramer's V) and multivariate (logistic regression) of predictors of these complications (P < .05).

RESULTS: In 49 of the 172 procedures complications were detected (28.5%).The most frequent complications were grade 1 (9.9%), 12 complications (6.9%) were classified as grade 2 by requiring additional medical treatment, 6 as grade 3A (3.5%), 7 as grade 3B (4.1%), 2 and 4A (1.1%), 4 and 4B (2.3%) and one and 5 (0.6%). In the univariate analysis, positive urine culture before surgery, the stones complex and larger than 40 mm of the same, showed a statistically significant association with the occurrence of complications (P < .05). The positive culture (OR: 2.96) and complex stones (OR: 3.03) proved to be independent variables predicting complications in multivariate analysis.

CONCLUSIONS: Clavien system allows a common language for classifying complications, expressing the degree of the same as the complexity of treatment required for resolution. The preoperative urine culture positivity and complex stone proved predictors of these complications in our serie.