Prognostic factors of morbidity in patients undergoing percutaneous nephrolithotomy

To determine the preoperative and perioperative predictive factors of morbidity/mortality in patients undergoing percutaneous nephrolithotomy (PCNL), using the Clavien's classification.

We performed a retrospective chart review of patients who underwent PCNL between January 2005 and January 2012. Preoperative and postoperative factors, such as age, obesity, surgical risk, Charlson comorbidity index, stone complexity, access calix, type of dilator used, and surgery time, were evaluated as predictors of complications.

A total of 354 patients were included in the study. Of these, 56% were women, with the average age of 47±12.5 years. Stone-free rate for noncomplex calculi was 85% and for complex calculi it was 68%. A total of 103 complications were recorded (29.3%). According to the modified Clavien classification system, 32 (9%) were grade 1, 39 (11%) were grade 2, 16 (4.5%) were grade 3A, 8 (2.3%) were grade 3B, 3 (0.8%) were grade 4A, 1 (0.3%) was grade 4B, and 4 (1.1%) were grade 5. In multivariate analysis female gender (odds ratio [OR] 3.1, confidence interval [CI] 1.1-8.0), Charlson score of ≥3 (OR 23.2, CI 3.5-151.1), complex stone (OR 4, CI 1.6-9.6), and duration of surgery of ≥120 minutes (OR 2.9, CI 1.2-6.9) were associated with major complications.

PCNL is a safe procedure with acceptable efficacy for the resolution of renal calculi. The safety of the procedure should improve, especially to reduce the presence of severe complications (Clavien ≥3). We identified factors that are associated with severe complications: female gender, high Charlson, complex calculi, and surgical length ≥120 minutes.