Jorge Moreno-Palacios

Evaluation and Comparison of Urolithiasis Scoring Systems Used in Percutaneous Kidney Stone Surgery

PURPOSE Contemporary predictive tools for percutaneous nephrolithotomy outcomes include the Guy stone score, S.T.O.N.E. nephrolithometry and the CROES nephrolithometric nomogram. We compared each scoring system in the same cohort to determine which was most predictive of surgical outcomes. METHODS We retrospectively reviewed the records of patients who underwent percutaneous nephrolithotomy between 2009 and 2012 at a total of 3 academic institutions. We calculated the Guy stone score, the S.T.O.N.E. nephrolithometry score and the CROES nephrolithometric nomogram score based on preoperative computerized tomography images. A single observer at each institution reviewed all images and assigned scores. Univariate and multivariate analysis was done to determine the most predictive scoring system. RESULTS We enrolled 246 patients in study. In stone-free patients vs those with residual stones the mean Guy score was 2.2 vs 2.7, the mean S.T.O.N.E. score was 8.3 vs 9.5 and the mean CROES nomogram score was 222 vs 187 (each p <0.001). Logistic regression revealed that the Guy, S.T.O.N.E. nephrolithometry and CROES nomogram scores were significantly associated with stone-free status (p = 0.02, 0.004 and <0.001, respectively). The Guy and S.T.O.N.E. nephrolithometry scores were associated with estimated blood loss (p <0.0001 and 0.03) and length of stay (p = 0.03 and 0.009, respectively). The CROES nomogram did not predict estimated blood loss or length of stay. CONCLUSIONS All scoring systems and the stone burden equally predicted stone-free status. The Guy and S.T.O.N.E. nephrolithometry scores were associated with estimated blood loss and length of stay. A single scoring system should be adopted to unify reporting.

Prognostic Factors of Morbidity in Patients Undergoing Percutaneous Nephrolithotomy

OBJECTIVE To determine the preoperative and perioperative predictive factors of morbidity/mortality in patients undergoing percutaneous nephrolithotomy (PCNL), using the Claviens classification. MATERIALS AND METHODS 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. RESULTS 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. CONCLUSIONS 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.

Evaluación de la tasa libre de litos posterior a la nefrolitotomía percutánea mediante el nomograma nefrolitométrico

BACKGROUND Percutaneous nephrolithotomy remains the standard of care for kidney stones larger than 2cm. Therefore, setting a prognosis for complete stone resolution through this method is essential. The prognostic tools available have limited prediction. OBJECTIVES To evaluate the stone-free rate in patients undergoing percutaneous nephrolithotomy with the Clinical Research Office of the Endourological Society nomogram and suggest modifications to improve the classification. MATERIAL AND METHODS We analyzed a retrospective cohort of patients undergoing percutaneous nephrolithotomy applying the nephrolithometric nomogram specified. We modified the scale dividing the patients into 3groups: i from 80 to 110 points, II from 111 to 170 points, and III more than 170 points, respectively assessing the stone-free rate (Kruskall-Wallis test was performed, p<0.05). RESULTS A total of 126 patients were included. According to the nehrolithometric nomogram the stone-free rate was 12.5% for patients with fewer than 111 points and 70.9% for those with 111 points or more. In the modification proposed for groups I, IIand III the stone-free rate was 12.5%, 50% and 80% respectively (p=0.000). CONCLUSIONS Evaluation using the nephrolithometric nomogram demonstrated accurate stone-free rate prediction for complex and simple stones, with a lack of discrimination for patients with intermediate scores. Our modification enabled better differentiation of the intermediate groups from the high and low stone-free rate groups.