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Shock wave lithotripsy (SWL) is an effective and commonly applied clinical treatment for human kidney stones. Yet the success of SWL is counterbalanced by the risk of retained fragments causing recurrent stone formation, which may require retreatment. This study has applied GeoBioMed experimental and analytical approaches to determine the size frequency distribution, fracture patterns, and reactive surface area of SWL-derived particles within the context of their original crystal growth structure (crystalline architecture) as revealed by confocal autofluorescence (CAF) and super-resolution autofluorescence (SRAF) microscopy. Multiple calcium oxalate (CaOx) stones were removed from a Mayo Clinic patient using standard percutaneous nephrolithotomy (PCNL) and shock pulse lithotripsy (SPL). This produced approximately 4–12 mm-diameter PCNL-derived fragments that were experimentally treated ex vivo with SWL to form hundreds of smaller particles. Fractures propagated through the crystalline architecture of PCNL-derived fragments in a variety of geometric orientations to form rectangular, pointed, concentrically spalled, and irregular SWL-derived particles. Size frequency distributions ranged from fine silt (4–8 μm) to very fine pebbles (2–4 mm), according to the Wentworth grain size scale, with a mean size of fine sand (125–250 μm). Importantly, these SWL-derived particles are smaller than the 3–4 mm-diameter detection limit of clinical computed tomography (CT) techniques and can be retained on internal kidney membrane surfaces. This creates clinically undetectable crystallization seed points with extremely high reactive surface areas, which dramatically enhance the multiple events of crystallization and dissolution (diagenetic phase transitions) that may lead to the high rates of CaOx kidney stone recurrence after SWL treatment. [ABSTRACT FROM AUTHOR]

Objective: To define risk factors and perioperative outcomes for matrix stones and compare these outcomes with struvite and calcium stone cohorts.Methods: A retrospective cohort study comparing matrix stones (n=32), struvite stones (n=23) and a matched, calcium stone control group (n=32) was performed. Two-way ANOVA was used to compare the groups for continuous variables. Chi-square tests were used to compare categorical variables. Significance was set at P <.05. All statistical tests were performed using R (v1.73).Results: We identified no differences in age, gender, or BMI between the three groups. Matrix and struvite stones were more likely to have a history of prior stone surgery and recurrent UTIs compared to calcium stones (P=.027 and P <.001, respectively). Struvite stones were more likely to present as staghorn calculi compared to matrix or calcium stones (56.5% vs 21.7% vs 18.8%, P=.006). There were no significant differences in postoperative stone free rates (P=.378). No significant differences in postoperative infectious complications were identified. Matrix stones were more likely to have Candida on stone culture compared to the struvite or calcium stones (P <.0001).Conclusion: Matrix and struvite stones were more likely have a history of stone surgery and preoperative recurrent UTIs. Struvite stones were more likely to present as staghorn calculi. Matrix stones were more likely to have Candida present in stone cultures. However, no difference in postoperative infectious outcomes or stone free rates were identified. Further study with larger cohorts is necessary to distinguish matrix stone postoperative outcomes from struvite and calcium stones. [ABSTRACT FROM AUTHOR]

Background: Coronavirus disease 2019 (COVID-19) changed the practice of medicine in America. During the March 2020 lockdown, elective cases were canceled to conserve hospital beds/resources resulting in financial losses for health systems and delayed surgical care. Ambulatory percutaneous nephrolithotomy (aPCNL) has been shown to be safe and could be a strategy to ensure patients receive care that has been delayed, conserve hospital resources, and maximize cost-effectiveness. We aimed to compare the safety and cost-effectiveness of patients undergoing aPCNL against standard PCNL (sPCNL). Materials and Methods: Ninty-eight patients underwent PCNL at Indiana University Methodist Hospital, a tertiary referral center, by three expert surgeons from January 2020 to September 2020. The primary outcome of the study was to compare the 30-day rates of emergency department (ED) visits, readmissions, and complications between sPCNL and aPCNL. Secondary outcomes included cost analysis and stone-free rates (SFRs). Propensity score matching was performed to ensure the groups were balanced. Statistical analyses were performed using SAS 9.4 using independent t-tests for continuous variables and chi-square analyses for categorical variables. Results: Ninety-eight patients underwent PCNL during the study period (sPCNL = 75 and aPCNL = 23). After propensity score matching, 42 patients were available for comparison (sPCNL = 19 and aPCNL = 23). We found no difference in 30-day ED visits, readmissions, or complications between the two groups. aPCNL resulted in cost savings of $5327 ± 442 per case. SFRs were higher for aPCNL compared with sPCNL. Conclusions: aPCNL appears safe to perform and does not have a higher rate of ED visits or readmissions compared with sPCNL. aPCNL may also be cost-effective compared with sPCNL. [ABSTRACT FROM AUTHOR]

Objective: To determine the true failure rate of opioid free ureteroscopy (OF-URS) and rates of new-persistent opioid use utilizing a national prescription drug monitoring program.Material and Methods: We identified 239 patients utilizing our retrospective stone database who underwent OF-URS from Februrary 2018-March 2020. In Feb 2018, we initiated a OF-URS pathway (diclofenac, tamsulosin, acetaminophen, pyridium and oxybutynin). Patients who had a contraindication to NSAIDs were excluded from primary analyses. A prescription drug monitoring program was then utilized to determine the number of patients who failed OF-URS (defined as receipt of an opioid within 31 days of surgery) as well as rates of new-persistent opioid use (defined as receipt of opioid 91-180 days after surgery). All statistical analyses were performed using SAS 9.4. Tests were 2-sided and statistical significance was set at P<0.05.Results: We found a OF-URS failure rate of 16.6% and 14.0% in the total and opioid naïve cohorts, respectively. Rates of new-persistent opioid use were 0.9% and 1.2%, respectively (lower than published expected rate of ~6% after URS with postoperative opioids). 91% of patients obtained opioid from alternative sources. Uni/multivariate analyses were performed for both cohorts. In the total cohort, benzodiazepine users had a lower risk of OF-URS failure on multivariate analysis. No variables were associated with OF-URS failure in the opioid naïve cohort.Conclusion: The true failure rate of OF-URS is higher than previously thought at 16.6% and 14.0%. However, efforts to reduce opioid prescriptions with OF-URS pathways have successfully reduced new-persistent opioid use. [ABSTRACT FROM AUTHOR]