Trans-splenic puncture during percutaneous nephrolithotomy: Outcome spectrum of the same complication

AbstractPercutaneous nephrolithotomy is an endourologic technique commonly used in the management of nephrolithiasis. However, this procedure is not complication-free. Splenic injury is exceptionally rare with a reported rate of 1% from the total case load. We present herein two cases of splenic puncture during percutaneous nephrolithotomy that illustrate two different outcomes. In the first case, the patient remained asymptomatic and was discharged on her third post-operative day after removing the nephrostomy, without any sign of hemodynamic compromise. In the second case, the patient presented with hemodynamic instability and an abdominal computed tomography scan was done that showed free fluid in the peritoneal cavity. Emergency laparotomy was performed and revealed a deep peripheral laceration (20mm×5mm in length) that required splenectomy. After a thorough review of the existing literature, we could find only 11 other instances of injury to the spleen in which treatment outcomes were reported. Patient hemodynamic status was the main factor in deciding on the type of treatment

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It is a standard practice to test for the signature of homologous recombination in studies examining the genetic diversity of bacterial populations. Although it has emerged that homologous recombination rates can vary widely between species, comparing the results from different studies is made difficult by the diversity of estimation methods used. Here, Multi Locus Sequence Typing (MLST) datasets from a wide variety of bacteria and archaea are analyzed using the ClonalFrame method. This enables a direct comparison between species and allows for a first exploration of the question whether phylogeny or ecology is the primary determinant of homologous recombination rate

Risk factors for postoperative complications of percutaneous nephrolithotomy at a tertiary referral center

Purpose: We sought to describe and evaluate the complications related to percutaneous nephrolithotomy and identify risk factors of morbidity according to the modified Clavien scoring system. We also sought to specify which perioperative factors are associated with minor and major complications. Materials and Methods: We retrospectively analyzed data on patients who underwent percutaneous nephrolithotomy from 1990 to 2013. Descriptive statistics were used to analyze patient characteristics, medical comorbidities and perioperative features. Complications were categorized according to the Clavien score for percutaneous nephrolithotomy. The Mann-Whitney and Fisher exact tests were used as appropriate. Logistic regression analysis was performed to look for prognostic factors associated with major complications. Results: A total of 2,318 surgeries were evaluated. Mean age of the population was 53.7 years. The stone-free rate at hospital discharge was 81.6%. The overall complication rate was 18.3%. Two deaths occurred. Patients with any postoperative complications were older, had more comorbidities, were more likely to have staghorn calculi and had longer operative time and hospital stay on univariate analysis (p <0.05). Age 55 years or older and upper pole access were independent predictors of major complications on multivariate analysis. Other factors such as a history of urinary tract infections, body mass index, stone composition, previous percutaneous nephrolithotomy and multiple tracts were not associated with a major complication. Conclusions: At our center percutaneous nephrolithotomy is an excellent option for complex kidney stone management with a low overall complication rate. Older patient age and upper pole access are significantly associated with an increased risk of a major complication

Combining Mean and Standard Deviation of Hounsfield Unit Measurements from Preoperative CT Allows More Accurate Prediction of Urinary Stone Composition Than Mean Hounsfield Units Alone

INTRODUCTION AND OBJECTIVES: The mineral composition of a urinary stone may influence its surgical and medical treatment. Previous attempts at identifying stone composition based on mean Hounsfield Units (HUm) have had varied success. We aimed to evaluate the additional use of standard deviation of HU (HUsd) to more accurately predict stone composition. METHODS: We identified patients from two centers that had undergone urinary stone treatment between 2006 and 2013 and had mineral stone analysis and a CT available. HUm and HUsd of the stones were compared with ANOVA. ROC analysis with Area Under the Curve (AUC), Youden Index and likelihood ratio calculations were performed. RESULTS: Data was available for 466 patients. The major component was CalciumOxalate Monohydrate (COM), Uric Acid, HydroxyApatite, Struvite, Brushite, Cystine and CO Dihydrate (COD) in 41.4%, 19.3%, 12.4%, 7.5%, 5.8%, 5.4% and 4.7% of the patients respectively. The HUm of UA and Br was respectively significantly lower and higher than the HUm of any other stone type. HUm and HUsd were most accurate in predicting uric acid with an AUC of 0.969 and 0.851 respectively. The combined use of HUm and HUsd resulted in increased positive predictive value and higher likelihood ratios for identifying a stone\u27s mineral composition for all stone types but COM. CONCLUSIONS: To the best of our knowledge this is the first report of CT data aiding in the prediction of brushite stone composition. Both HUm and HUsd can help predict stone composition and their combined use results in higher likelihood ratios influencing probability

Multicenter external validation and comparison of stone scoring systems in predicting outcomes after percutaneous nephrolithotomy

Background and Purpose: Several scoring systems have recently emerged to predict stone-free rate (SFR) and complications after percutaneous nephrolithotomy (PCNL). We aimed to compare the most commonly used scoring systems (Guy's stone score, S.T.O.N.E. nephrolithometry, and CROES nomogram), assess their predictive accuracy for SFR and other postoperative variables, and develop a risk group stratification based on these scoring systems. Materials and Methods: We performed a retrospective review of patients who have had a PCNL at four academic institutions between 2006 and 2013. Primary outcome was SFR within 3 weeks of the surgery and secondary outcomes were operative time (OT), complications, and length of stay (LOS). We performed chi-squared, t-test, logistic, linear, and Poisson regressions, as well as receiver operating characteristics curve with area under the curve (AUC) calculation. Results: We identified 586 patients eligible for analysis. Of these, 67.4% were stone free. Guy's, S.T.O.N.E., and CROES score were predictive of SFR on multivariable logistic regression (odds ratio [OR]: 1.398, 95% confidence interval [CI]: 1.056, 1.852, p=0.019; OR: 1.417, 85% CI: 1.231, 1.631, p<0.001; OR: 0.993, 95% CI: 0.988, 0.998, p=0.004) and have similar predictive accuracy with AUCs of 0.629, 0.671, and 0.646, respectively. On multivariable linear regression, only S.T.O.N.E. was an independent predictor of longer OT (=14.556, 95% CI: 12.453, 16.660, p<0.001). None of the scores were independent predictors of postoperative complications or a longer LOS. Poisson regression allowed for risk group stratification and showed the S.T.O.N.E. score and CROES nomogram to have the most distinct risk groups. Conclusions: The three evaluated scoring systems have similar predictive accuracy of SFR. S.T.O.N.E. has additional value in predicting OT. Risk group stratification can be used for patient counseling. Further research is needed to identify whether or not any is superior to the others with regard to clinical usefulness and predictive accuracy