Introduction and Objective: Current available lithotrites have clinical stone clearance rates averaging 24 to 32 mm2/minute. The objective of this study was to critically evaluate the initial exper...
Renal access in percutaneous nephrolithotomy (PCNL) may be obtained via a pre-existing nephrostomy tube (NT) tract; however, emergent NTs are not always ideal for subsequent surgery. We sought to determine the rate of NT tract usability and assess factors related to the usability of emergently placed NTs.A retrospective review was performed of UC San Diego subjects undergoing percutaneous renal surgery between January 2016 and October 2018. Demographics and peri-operative variables were collected. The primary outcome was the usability of NT tract for dilation and instrumentation. "Usable" indicated a tract in which PCNL could be completed; "unusable" indicated lack of dilation and the requirement of additional tract(s) for PCNL.35 PCNL cases had previous emergently placed NT which were indwelling at time of percutaneous surgery. 51% of these NT tracts (18/35) were deemed usable and dilated for PCNL. No significant difference was seen between usable and unusable NT groups for number of dilated tracts during PCNL (p=0.13), or either the location of indwelling NT (p=0.96) or renal stones (p=0.95). In the usable NT tract cohort PCNL access was via the lower pole 56% of the time, where as when previous NT tracts were deemed unusable, a separate upper-pole access was obtained intra-operatively 53% of the time (p<0.01).Pre-existing, emergent NTs served a ssufficient PCNL access tracts in over half of recorded cases. Contrary to recently published reports, the utility of pre-existing NTs appears to vary among health systems. Other variables, including the desired location of PCNL appear to directly influence the like lihood of NT tract usability.El acceso renal en la nefrolitotomía percutánea puede obtenerse a través de una nefrostomía pre-existente, aunque las nefrostomías urgentes no siempre son ideales para la posterior cirugía. Nosotros intentamos determinar la tasa de uso del tracto de nefrostomía y los factores de acceso relacionados con el uso de la nefrostomía urgente.MÉTODOS: Una revisión retrospectiva se realizó en UC San Diego de los pacientes que habían recibido cirugía renal percutánea entre enero 2016 y octubre 2018. Las variables demográficas y perioperatorias fueron recolectadas. El objetivo primario fue el uso del trayecto de nefrostomía después de dilatación e instrumentación.¨Usable” indicó un trayecto en el que la nefrolitotomía percutánea se completo. “No usable” indicó falta de dilatación y el requerimiento de un nuevo trayecto para la cirugía percutánea.35 casos de nefrolitotomía percutánea tenían nefrostomías urgentes previamente y presentes al empezar la cirugía. 51% de estos trayectos (18/35) fueron usados y dilatados para la nefrolitotomía percutánea. No hubo diferencias significativas entre los trayectos usables y no usables en el numero de trayectos dilatados durante la cirugía percutánea (p=0,13), ni en la localización de la sonda de nefrostomía (p=0,96) o las litiasis renales (p=0,95). En el grupo de pacientes con nefrostomía usable, en el 56% la nefrostomía accedía por el polo inferior. Cuando el trayecto de nefrostomía se considero no usable, un nuevo acceso intraoperatorio por el polo superior fue obtenido en el 53% de lo scasos (p<0,01).El trayecto de nefrostomía pre-existente fue suficiente para el acceso percutáneo en la mitad de los casos. Contrario a lo publicado recientemente, la utilidad de la nefrostomía pre-existente parece variar según el Sistema sanitario. Otras variables, incluyendo la localización deseada para la nefrostomía influencia el uso del trayecto.
Little is known about the incidence of nephrolithiasis in the United States Navy. Navy pilots must be kidney stone-free and are often referred for treatment of small asymptomatic stones. The primary objectives of this study were to determine the incidence of nephrolithiasis and computerized tomography, proportion undergoing treatment and incidence of stone related mishaps in Navy pilots compared with other Navy personnel.We retrospectively studied the records of all Navy service members from 2002 to 2011 for nephrolithiasis based on ICD-9 stone codes to determine the mentioned rates. We also reviewed NSC (Naval Safety Center) data for a history of accidents associated with nephrolithiasis. Rates of disease were calculated using person-years of followup and inferential statistics were done using univariable and multivariable analyses.We evaluated 667,840 Navy personnel with a total of 3,238,331 person-years of followup. The annual incidence of nephrolithiasis was 240/100,000 person-years with a 5-year recurrence rate of 35.3%. On multivariable analysis pilots had nephrolithiasis incidence and treatment rates similar to those of the overall Navy population. Women had a higher incidence of nephrolithiasis compared with men (OR 1.17, p <0.0001). The rate of computerized tomography was lower in pilots than in the rest of the Navy (39 vs 66/10,000 person-years, p <0.0001). No recorded accidents were associated with kidney stones.Navy pilots had a similar incidence of nephrolithiasis and were no more likely to undergo a surgical procedure. Given that no accidents were associated with nephrolithiasis, this study suggests reconsidering current military policies necessitating pilots to be completely stone-free.
We performed a decision analysis model of the cost-effectiveness of observation vs intervention for asymptomatic residual fragments less than 4 mm in diameter following ureteroscopic holmium laser lithotripsy.Outcomes data from a retrospective analysis evaluating the natural history, complications and reintervention rates of asymptomatic residual stone fragments performed by the EDGE (Endourology Disease Group for Excellence) Research Consortium were used. A decision analysis model was constructed to compare the cost-effectiveness of initial observation of residual fragments to immediate intervention. Cost of observation included emergency room visits, hospitalizations and reinterventions. The cost analysis model extended to 3 years to account for delayed reintervention rates for fragments less than 4 mm. Costs of emergency department visits, readmissions and reinterventions were calculated based on published figures from the literature.Decision analysis modeling demonstrated that when comparing initial observation to immediate reintervention, the cost was $2,183 vs $4,424. The difference in cost was largely driven by the fact that over 3 years, approximately 55% of all patients remained asymptomatic and did not incur additional costs. This represents an approximate annual per patient savings of $747, and $2,241 over 3 years when observation is selected over immediate reintervention.Our decision analysis model demonstrates superior cost-effectiveness for observation over immediate reintervention for asymptomatic residual stones less than 4 mm following ureteroscopic lithotripsy. Based on these findings careful stratification and selection of patients may enable surgeons to improve cost-effectiveness of managing small, asymptomatic residual fragments following ureteroscopic lithotripsy.
To determine to what extent urologists with no specific training agree upon level of evidence (LoE) ratings of studies published in the urological literature, as LoE are commonly referenced as a measure of evidence quality.In all, 86 clinical research studies published in four major urology journals were reviewed. Each article was independently reviewed by eight reviewers using a standardized data abstraction form. Articles were assessed for type of study (therapy, prognosis, diagnosis or economic) and LoE (I, II, III or IV). Reviewers received only written instructions and no formal training in the application of this classification system.Of the 86 articles, 69% related to therapy, 16% to prognosis, and 15% to diagnosis. Eight studies (9%) provided Level I evidence, 18 studies (21%) Level II, 14 studies (16%) Level III and 46 studies (54%) Level IV evidence. The intraclass correlation coefficient (95% confidence interval) based on all reviewers (eight reviewers) was 0.67 (0.59-0.74; P= 0.001) for the type of study and 0.55 (0.48-0.64; P= 0.001) for the LoE. In an analysis limited to a subset of studies in which all reviewers agreed upon the type of study question (n= 40) the intraclass correlation coefficient was 0.79 (0.70-0.86; P= 0.001).In the present study there was a low interobserver agreement for LoE ratings by urologists with no specific training. These findings suggest caution in the interpretation of LoE ratings and emphasize the importance of specific training for individuals that are charged with quality of evidence determinations.
Introduction: To evaluate flexible ureteroscope working channels with a 1.06 mm digital borescope (Clarus Medical, Minneapolis, MN) and identify factors contributing to ureteroscope damage over time. Materials and Methods: We performed a single institutional prospective study of patients undergoing stone surgery using a nondisposable flexible ureteroscope. A 1.06 mm borescope was used to evaluate ureteroscopes before and after surgery. Borescope videos were reviewed by two independent researchers to quantify average pre- and postprocedural damage. Results: Twenty-five procedures were performed with pre- and postprocedural borescope assessment between August 2021 and February 2022. All patients received preoperative CT imaging depicting a mean axial stone size of 14.1 ± 8.4 mm and density of 923.4 ± 458.1 HU. Mean operative time was 63.8 ± 34.0 minutes. The average number an instrument passes through the working channel was 2.1 ± 1.6. Laser was used in 11 cases with mean laser time of 18.8 ± 19.7 minutes and mean total energy of 5.8 ± 4.2 KJ. On preoperative assessment, all ureteroscopes had some form of defect (24% shave, 32% pinhole, 96% dents and scratches, and 28% discolorations). During postoperative assessment, 23/25 (92%) ureteroscopes showed additional damage with an average of 3.7 ± 2.8 imperfections acquired after one use. Significant differences were seen in acquired shavings (p = 0.028) and scratches or dents (p = 0.018). Of the 355 imperfections seen on postoperative evaluation, 0.4% were shave, 3% were pinhole, 85.8% were dents and scratches, and 10.8% were discolorations. Conclusion: The Clarus borescope observed defects after the majority of flexible ureteroscopy procedures for nephrolithiasis. Although such disruptions may not immediately render ureteroscopes nonfunctional, they are more common than previously described and could increase maintenance costs. Further studies are needed to investigate the burden of unit damage per procedure to raise operator awareness and reduce preventable ureteroscope imperfections.
