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INTRODUCTION: We sought to identify predictors of failed retrograde ureteric stent (FRS) placement in the setting of obstructing ureteric calculi. In addition to patient- and stone-specific characteristics, we also considered computed tomography (CT) measures of ureteric wall thickness (UWT), as it has shown clinical potential in predicting outcomes of shockwave lithotripsy, ureteroscopy, and spontaneous stone passage. METHODS: We performed a retrospective, case-control study comparing patients who had successful retrograde stent (SRS) insertions with those who failed stent placement and ultimately required nephrostomy tube (NT) insertion (2013-2019). Patients were identified using administrative data from a shared electronic medical record (capturing all urology patients in our geographic area) and a prospective database capturing all institutional interventional radiology procedures. Patient demographics, as well as clinical and stone characteristics were then collected, and imaging manually reviewed. Statistical analysis was performed using univariate and multivariate logistic regression analysis in collaboration with a statistician. RESULTS: A total of 109 patients met inclusion for analysis (34 FRS, 75 SRS). The most common indication for stent insertion included sepsis (79%). On multivariate analysis both acute kidney injury as primary indication for stent insertion (odds ratio [OR] 9.16, 95% confidence interval [CI] 1.91-44.00, p=0.006) and UWT (OR 0.34, 95% CI 0.15-0.74, p=0.007) were found to be significantly associated with failed retrograde stent placement. A receiver operator characteristic curve analysis demonstrates an optimal UWT cutoff of 3.2 mm (sensitivity 60.6%, specificity 83.3%). CONCLUSIONS: Elevated UWT and acute kidney injury as an indication for urgent urinary decompression in the setting of obstructing ureteric stones are predictive of failed retrograde stent placement. These patients may benefit from upfront nephrostomy tube insertion.
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INTRODUCTION: Non-contrast computed tomography (CT) is the gold-standard diagnostic test for urolithiasis. Little is published regarding which information needs to be included in the report for it to be most useful to the healthcare team for efficient triage and high-quality patient care. This study aimed to assess the quality and variability of CT scan reporting at a single Canadian tertiary academic medical center. METHODS: We completed a retrospective review of 100 consecutive renal colic CT scans. Descriptive statistics were used to report the frequency with which specific elements commonly used by urologists to triage and treat patients were included in radiology reports. RESULTS: Our sample had a mean age of 51.4±13.1 years. Stone size was universally reported for obstructing stones but was less frequently reported for non-obstructing stones (100% vs. 86.8%). A similar trend was observed for the exact stone number (100% vs. 93.4%). Non-obstructing stones were more likely than obstructing stones to be reported in one dimension (77.5% vs. 47%). Obstructing stones were reported in three dimensions 27% of the time. CT reports commonly include the presence or absence of hydronephrosis status (98%) but are less likely to include renal size (32%) and periureteral stranding (16%). Hounsfield units (HU) were reported in 3% of the reports, but skin-to-stone distance (SSD) and radiation dose were never reported. CONCLUSIONS: Reports routinely included assessments of stone size, location, and number (although not uniformly). HU, SSD, and radiation dose were rarely reported. This provides insight into opportunities for standardized reporting to optimize knowledge transfer that may result in clinical efficiency and improved quality of patient care.
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Introduction: Establishing percutaneous renal access is the key initial step to percutaneous nephrolithotomy; however, learning the technique during surgery for trainees is complicated by the number of approaches used to gain access, limited completion time during a breath hold. and attempt to minimize the number of passes through a kidney. There are many training models for percutaneous access commercially available all with their respective limitations. Our objective was to develop a low-cost, high-fidelity percutaneous access training model that addresses existing limitations and can be used with both ultrasound and fluoroscopy guidance. Methods: After a formal ethics exemption was attained, pig cadavers were harvested for flank, kidneys, and ureters. These were incorporated into a composite porcine tissue mould, created within a gelatin matrix. In the initial assessment, establishing percutaneous access under both ultrasound and fluoroscopy guidance was tested to refine usability. Once acceptable, its use during a training course was evaluated to assess impressions for use with ultrasound. Results: We were able to create a $45USD biodegradable model, which can facilitate percutaneous access using: fluoroscopy with intrarenal contrast; fluoroscopy with endoscopic guidance; and fluoro-less that is, ultrasound only. A cohort of 12 Canadian Postgraduate Year-3 residents who used the model for ultrasound access agreed that the model simulated a comparable tactile experience (58.33%) and anatomy (75%) to humans. Furthermore, majority of the residents agreed that model was easy to use with ultrasound guidance (91.67%), was a beneficial experience for their learning and future practice (83.33%) and if available would use to complement their intraoperative training (83.33%). Conclusion: We were able to develop a low-cost, preliminarily tested ex vivo pig model for percutaneous access compatible with multiple imaging modalities. We will continue refining our model and seek to understand its benefits when teaching percutaneous access to varying levels of learners.
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Riñón , Modelos Animales , Animales , Fluoroscopía , Porcinos , Riñón/diagnóstico por imagen , Riñón/cirugía , Nefrolitotomía Percutánea/métodos , Nefrolitotomía Percutánea/educación , Ultrasonografía/métodos , Humanos , Sus scrofaRESUMEN
INTRODUCTION: Our objective was to assess the incidence of kidney stones requiring acute care, trends in the surgical treatment of stones, and the demographics of stone formers in Canada. METHODS: We conducted a population-based, retrospective cohort study using administrative data from the Canadian Institute for Health Information. We included Canadian residents age >18 years, outside of Quebec, who presented between January 1, 2013, and December 31, 2018, with a kidney stone episode. This was defined as a kidney stone resulting in hospital admission, emergency department visit, or stone intervention, specifically shockwave lithotripsy (SWL), ureteroscopy (URS), or percutaneous nephrolithotomy (PCNL). RESULTS: There were 471 824 kidney stone episodes, including 184 373 interventions. The number of kidney stone episode increased from 277/100 000 in 2013 to 290/100 000 in 2018. The median age was 53 (interquartile range 41-65) years and 59.9% were male. The crude rate for stone intervention was 877/100 000. The age- and gender-standardized rate for interventions was highest in Nova Scotia and Newfoundland and Labrador, and lowest in Prince Edward Island. The most common intervention in Canada was URS (73.5%), followed by SWL (19.8%) and PCNL (6.7%). The percent utilization of SWL was highest in Manitoba, whereas for URS, it was highest in Prince Edward Island and Alberta. CONCLUSIONS: Our study provides the first population-based data on the demographics of stone formers and treatment trends across Canada. There has been a 4.7% increase in kidney stone episodes over the study period. Those presenting to hospital or requiring intervention for a kidney stone are more likely to be male, aged 41-65, and undergo URS.
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INTRODUCTION: 5α-reductase inhibitors (5ARI) are commonly prescribed medications. There is ongoing controversy about the adverse events of these medications. The aim of this study is to characterize lawsuits in Canada involving medical complications of 5ARIs use. MATERIALS AND METHODS: Legal cases were queried from CanLII. Cases were included if they involved a party taking a 5ARI who alleged an adverse event. Relevant full cases were retained, and pertinent characteristics were extracted with the help of a legal expert. RESULTS: Our deduplicated search yielded 67 unique legal documents from December 2013 to February 2019. Twelve of these documents met the inclusion criteria (representing 3 cases, considering each case had several hearings). The medical complaints filed by the plaintiffs were all related to medication side effects (n = 3, 100%). The plaintiffs were commonly patients themselves. Defendants were exclusively pharmaceutical companies. Persistent erectile dysfunction after stopping the medication was cited as a side effect in all complaints. The prescriptions were made for male pattern hair loss (n = 3, 100%) in all cases. All cases represent class actions brought by the plaintiffs, and they have been certified by their respective court. However, the cases are still ongoing. CONCLUSION: While 5ARI use has been linked to undesired sexual side effects, there have been few litigations on this issue in Canada. Persisting sexual dysfunction after stopping the medication is the only complaint presented in legal action. To date, no judgment against a physician or pharmaceutical company was identified. Cases are still ongoing.
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Inhibidores de 5-alfa-Reductasa , Disfunción Eréctil , Humanos , Masculino , Canadá , Inhibidores de 5-alfa-Reductasa/efectos adversos , Disfunción Eréctil/inducido químicamente , Disfunción Eréctil/tratamiento farmacológico , Preparaciones Farmacéuticas , OxidorreductasasRESUMEN
PURPOSE: Ureteral stone impaction is associated with unfavorable endourological outcomes; however, reliable predictors of stone impaction are limited. We aimed to assess the performance of ureteral wall thickness on noncontrast computed tomography as a predictor of ureteral stone impaction and failure rates of spontaneous stone passage, shock wave lithotripsy, and retrograde guidewire and stent passage. MATERIALS AND METHODS: This study was completed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. A search was conducted in April 2022 for all adult, human, and English language studies investigating ureteral wall thickness using PROSPERO, OVID Medline, OVID EMBASE, Wiley Cochrane Library, Proquest Dissertations & Theses Global, and SCOPUS. A systematic review and meta-analysis using random effects model was conducted. Risk of bias was assessed using the MINORS (Methodological Index for Non-randomized Studies) score. RESULTS: Fourteen studies with a pooled population of 2,987 patients were included for quantitative analysis, and 34 studies were included in our qualitative review. Meta-analysis findings suggest that a thinner ureteral wall thickness is associated with more favorable subgroup stone outcomes. Thinner ureteral wall thickness suggests a lack of stone impaction and was associated with improved rates of spontaneous stone passage, successful retrograde guidewire and stent placement, and improved shock wave lithotripsy outcomes. Studies lack a standardized ureteral wall thickness measurement protocol. CONCLUSIONS: Ureteral wall thickness is a noninvasive measure that predicts ureteral stone impaction, and thin measurements are predictive of successful outcomes. Variability in measurement methods confirms that a standardized ureteral wall thickness protocol is needed, and the clinical utility of ureteral wall thickness is yet to be determined.
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Litotricia , Uréter , Cálculos Ureterales , Adulto , Humanos , Uréter/diagnóstico por imagen , Cálculos Ureterales/diagnóstico por imagen , Cálculos Ureterales/terapia , Cálculos Ureterales/complicaciones , Litotricia/métodos , Tomografía Computarizada por Rayos X/métodos , Stents , Resultado del TratamientoRESUMEN
PURPOSE: Patients presenting with multiple same-sided ureteric stones (MSSUS) are a unique population with nuanced prognostic and treatment considerations, which have yet to be characterized in the literature. Therefore, our purpose was to examine outcomes of patients with MSSUS vs those with single ureteric stones (SUS). METHODS: A retrospective review of prospectively collected patients included adults (> 18yo) with [Formula: see text] 2 ipsilateral ureteral stones without prior treatment for their current stone burden. A historical comparison group was used as a control population. Univariate logistic regression analyses and descriptive statistics were performed with SPSS® 20.0 (p < 0.05). RESULTS: Seventy-nine MSSUS patients were compared to 101 SUS patients. MSSUS patients had 2.21 [Formula: see text] 0.66 ureteric stones and had significantly smaller lead stones (MSSUS 6.4 mm vs SUS 7.2 mm, p = 0.03). MSSUS patients were more likely to have had prior stones (66 vs 42%) and 5.9 times more likely to have had prior stone procedures. Conservative management was successful in 30% MSSUS vs 19% SUS (p = 0.073), and there were no differences in resolution time (p = 0.44). For patients proceeding to intervention, (MSSUS n = 52, SUS n = 78), ureteroscopy was performed on 58% MSSUS vs 51% SUS patients (p = 0.302), and shockwave lithotripsy in 10% MSSUS vs 26% SUS (p = 0.01). MSSUS were more likely to spontaneously pass a stone prior to planned intervention (OR = 41.1; 95% CI = 12.0-140.7; p = 0.0001). CONCLUSION: MSSUS patients are more likely recurrent stone formers with extensive stone histories and current stone burdens. Conservative management appears as successful between groups, with no difference in resolution time. When employed, ureteroscopy outcomes do not different between cohorts.
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Litotricia , Uréter , Cálculos Ureterales , Adulto , Humanos , Litotricia/métodos , Estudios Retrospectivos , Resultado del Tratamiento , Cálculos Ureterales/terapia , Ureteroscopía/métodosRESUMEN
INTRODUCTION: Approximately 8% of patients that undergo therapeutic or diagnostic ureteroscopy will have the procedure aborted and ureter stented due to failed access. The primary objective of this study was to assess mean stent duration prior to repeat ureteroscopy and to calculate the associated successful access rate. METHODS: This retrospective, descriptive study evaluated all patients undergoing interval ureteroscopy following a failed procedure by endourologic surgeons at the University of Alberta from 2016-2018. Patients declining interval ureteroscopy, or those with malignant/known ureteral strictures were excluded from the study. The primary outcome measures were median time to salvage ureteroscopy and the rate of successful access of the repeat procedure. RESULTS: A total of 119 patients were identified as having a failed ureteroscopy during our study period. First-time and recurrent stone formers accounted for 64 (53.8%) and 47 (39.5%) patients, respectively. Median stent duration to second procedure was 17 days (average 20, range 10-84). Most patients had their repeat ureteroscopy at 14 days or greater (81.5%); 22 (18.5%) patients had their repeat ureteroscopy between 10 and 13 days. The success rate of a second ureteroscopy after stenting was 99.2% (118/119). CONCLUSIONS: Ureteric stenting following failed ureteroscopy leads to exceedingly high rates of successful access at interval procedure (99.2%). The standard duration of ureteric stenting employed at our institution is two weeks. Of the patients that underwent an accelerated second procedure (between 10-13 days of stenting), all had successful access at their interval procedure.
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INTRODUCTION: Failed access ureteroscopy (FA) describes the inability to gain adequate access to a stone to allow for treatment. The purpose of this study was to identify the prevalence of, and factors predicting FA in patients presenting with renal and ureteral stones. METHODS: We conducted a retrospective review of all ureteroscopy (URS) procedures performed for renal and ureteral stones by three endourologists over a six-month period at our center. All patients who underwent URS for the purpose of stone treatment were included. Patients were excluded if they underwent URS for non-stone diagnosis or treatment. FA was investigated in relation to demographics, medical history, stone-specific characteristics, procedure-specific characteristics, etc. Statistical analysis consisted of descriptive statistics, as well as Chi-squared and t-test analysis using SPSS statistical software version 24.0. RESULTS: A total of 188 cases were reviewed, with 8% of patients experiencing FA. Patient age, gender, body mass index (BMI), American Society of Anesthesiologists (ASA) score, emergency cases, previous stone treatment, use of computed tomography (CT) imaging, presence of hydronephrosis, and surgeon did not differ significantly between FA and successful access (SA) groups. Stone size (9.88±5.8 vs. 8.76±4.3 mm; p=0.361) was also not significantly different. However, a significant difference was noted in time from first diagnosis to URS (128 vs. 65 days, p=0.044) between the FA and SA groups, respectively. Similarly, for ureteral stones, the FA group had a significantly greater proportion of stones located in the proximal ureter (62.5% vs. 22.0%, p=0.043). CONCLUSIONS: Proximal ureteric stones were more likely to result in FA URS, and FA procedures were more likely to be preceded by extended time from first diagnosis to URS. Further investigation is necessary, and all endourology centers should track their own personal outcome data to allow for more meaningful analysis to be performed to improve patient outcomes.
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PURPOSE: We assessed the accuracy of patient reported outcomes for predicting spontaneous ureteral stone passage. MATERIALS AND METHODS: Patients with new unilateral ureteral calculi were prospectively assessed regarding current symptoms and whether they believed their stone had passed. The primary outcome was successful spontaneous stone passage as confirmed by ultrasound, and kidney, ureter and bladder x-ray. Spontaneous stone passage was compared to patient reported outcome responses to assess accuracy. RESULTS: Of the 212 patients 105 (49.5%) had successful spontaneous stone passage at a mean followup of 17.6 days. Compared to the unsuccessful spontaneous stone passage group, those with successful spontaneous stone passage had significantly smaller (mean 5.4 vs 7.6 mm), more distal (71.4% vs 34.6%) stones with slightly longer average time to followup at first visit (19.2 vs 16.0 days). Additionally, there was more patient reported cessation of pain (77.1% vs 44.9%) and perceived stone passage (55.2% vs 13.1%) in this group. Cessation of pain was 79.7% (95% CI 67.1-89.0) sensitive and 55.8% (95% CI 44.0-67.1) specific for successful spontaneous stone passage. Likewise, patient reported stone passage was 59.3% (95% CI 45.7-71.9) sensitive and 87.0% (95% CI 77.4-93.5%) specific. In the multivariable logistic regression analysis cessation of pain (OR 4.02, 95% CI 1.91-8.47, p <0.01) and reported stone passage (OR 3.79, 95% CI 1.73-8.28, p <0.01) were independent predictors of successful spontaneous stone passage. CONCLUSIONS: Cessation of pain and patient reported stone passage are independent predictors of successful spontaneous stone passage. However, both assessments may incorrectly gauge spontaneous stone passage, which raises concern for their validity as a sole clinical end point.
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Medición de Resultados Informados por el Paciente , Cálculos Ureterales/diagnóstico por imagen , Alberta , Femenino , Humanos , Masculino , Persona de Mediana Edad , Dimensión del Dolor , Estudios Prospectivos , Remisión EspontáneaRESUMEN
INTRODUCTION: Despite cystoscopy being among the most commonly performed urological procedures, there is a paucity of information on patient comprehension and retention of cystoscopy outcomes. A quality assessment performed at our center revealed low rates of patient understanding in our current care model. Therefore, we assessed patient comprehension of outpatient cystoscopy outcomes before and after the implementation of a formal written communication tool in the form of a summative patient handout to improve physician-patient communication. METHODS: Consecutive patients reporting for cystoscopy at a Canadian tertiary care center were assessed with postprocedure questionnaires before and after the implementation of a summative patient handout to facilitate the communication of results and followup plans. Comparisons were made with the Chi-squared test (p <0.05). RESULTS: A total of 650 questionnaires were analyzed (500 baseline and 150 postsummative patient handout). Of the respondents 448 (69%) were male and the mean age was 66 years old (total range 21 to 94 years) with 32% being under 60 years old. The proportion of patients who felt their results were discussed with them after implementation of the summative patient handout improved (94% vs 87%, p=0.02). Similarly, we improved concordance of patient reported and urologist reported cystoscopy results (75% vs 56%, p <0.001). Finally, we improved patient identification of their postcystoscopy followup plan (80% vs 51%, p <0.001). CONCLUSIONS: The implementation of a summative patient handout after local cystoscopy improved patient understanding of their procedural results and postcystoscopy followup plans.
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INTRODUCTION: Cystourethroscopy is one of the most common procedures performed by urologists in both office and operative settings. With the recent centralization of cystoscopy at our center, we looked to assess our current delivery model, to determine whether patients prefer their initial visit to be in cystoscopy or in the clinic, followed by a cystoscopy appointment later. METHODS: We administered 500 prospective questionnaires to adults undergoing cystoscopy by 14 urologists at our center in 2017. Patient demographics were collected, along with their questionnaire results that we compared to their urologist-reported indication, results, and plan. Our primary objective was to assess whether patients prefer to be seen direct to cystoscopy (DTC) vs. a clinic appointment (CA) before cystoscopy. RESULTS: A total of 500 questionnaires were analyzed, with 336/500 (67%) patients being male. Mean age was 66 years (21-93), with 30% under 60 years. Thirty-nine percent (n=193) were undergoing their first cystoscopy, with 85% preferring DTC. There was no difference in age, gender, first-time cystoscopy, or indication for cystoscopy when comparing those who preferred DTC vs. CA. Patients who had an accurate understanding of the indication for their cystoscopy had 6.23 times higher odds of preferring DTC (p<0.05). We also identified a deficiency in patient comprehension of cystoscopy results and followup plans. CONCLUSIONS: With limited health resources, a large patient catchment area, and the majority of patients preferring to be seen DTC, there is evidence to implement a default DTC approach to booking cystoscopy clinics.
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INTRODUCTION: We aimed to determine if there is a correlation between International Prostate Symptom scores (IPSS) and 24-hour urine collection volumes, as patients experiencing lower urinary tract symptoms (LUTS) may have impaired ability to increase fluid intake for stone prevention. METHODS: We conducted a single-centre, retrospective review was performed of stone-formers presenting from 2014-2016. Inclusion criteria were completion of an IPSS questionnaire and a 24-hour urine collection. Exclusion criteria included symptomatic stone or urinary tract infection at time of IPSS completion, inadequate 24-hour collection, or incomplete IPSS questionnaire. RESULTS: A total of 131 patients met inclusion criteria. Stratification by IPSS severity into mild (0-7), moderate (8-19), and severe (20-35) yielded groups of n=96, 28, and 7, respectively. Linear regression modelling did not reveal a correlation between IPSS score and volume (p=0.10). When compared to those with adequate urine volumes (>2 L/day, n=65), low-volume patients (<1 L/day, n=10) had a significantly higher total IPSS (11.7 vs. 6.1; p=0.036). These groups showed significant differences in their responses to questions about incomplete emptying (p=0.031), intermittency (p=0.011), and stranguria (p=0.0020), with higher scores noted in the low urine output group. CONCLUSIONS: This study is the first to examine the correlation between IPSS and 24-hour urine volume. Though our data does not show a linear relationship between urine output and IPSS, those with lower urine volumes appear to have worse self-reported voiding symptoms when compared to those with adequate volumes (>2 L/day) for stone prevention. The overall number of patients in our study is relatively small, which may account for the lack of a relationship between IPSS and 24-hour urine volumes.
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ABSTRACT Objectives: To investigate the seasonal variations in urinary calcium, serum vitamin D, and urinary volume in patients with a history of nephrolithiasis. Materials and Methods: Patients included were those who completed a 24-hour urine metabolic evaluation on two occasions; one in summer (June-Aug) and one in winter (Nov-Jan), and who had not started any medications or been instructed on dietary modifications in the interval between the two tests that may have impacted the results. Patients were excluded if they were on thiazide diuretics or were taking calcium and / or Vitamin D supplementation. Welch's t-test was used to compare the difference in average summer and winter values. Unpaired Student t-test was used to compare baseline parameters (age, BMI), and Paired Student t-test was used to compare average seasonal measurements in men vs. women. Results: 136 patients were identified who were not taking calcium or vitamin D supplements or thiazide diuretics, and who were not instructed on dietary modifications in the interval between the two measured parameters. No significant differences were observed when comparing male to female baseline parameters of age or BMI (Table-1). Average 24-hour urine calcium was higher (226.60) in the winter than in summer (194.18) and was significant in males (p = 0.014) and females (p < 0.001). No significant seasonal difference was seen in 24-hour urine volume or serum vitamin D levels. Conclusions: Urinary calcium is higher in winter months compared to summer months. As such, tailoring medical preventative strategies to the time of year may be helpful.
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Humanos , Femenino , Vitamina D/orina , Cálculos Renales/orina , Calcio/orina , Estaciones del Año , Cálculos Renales/etiología , Estudios Retrospectivos , Urinálisis , Persona de Mediana EdadRESUMEN
OBJECTIVES: To investigate the seasonal variations in urinary calcium, serum vitamin D, and urinary volume in patients with a history of nephrolithiasis. MATERIALS AND METHODS: Patients included were those who completed a 24-hour urine metabolic evaluation on two occasions; one in summer (June-Aug) and one in winter (Nov-Jan), and who had not started any medications or been instructed on dietary modifications in the interval between the two tests that may have impacted the results. Patients were excluded if they were on thiazide diuretics or were taking calcium and / or Vitamin D supplementation. Welch's t-test was used to compare the difference in average summer and winter values. Unpaired Student t-test was used to compare baseline parameters (age, BMI), and Paired Student t-test was used to compare average seasonal measurements in men vs. women. RESULTS: 136 patients were identified who were not taking calcium or vitamin D supplements or thiazide diuretics, and who were not instructed on dietary modifications in the interval between the two measured parameters. No significant differences were observed when comparing male to female baseline parameters of age or BMI (Table-1). Average 24-hour urine calcium was higher (226.60) in the winter than in summer (194.18) and was significant in males (p = 0.014) and females (p < 0.001). No significant seasonal difference was seen in 24-hour urine volume or serum vitamin D levels. CONCLUSIONS: Urinary calcium is higher in winter months compared to summer months. As such, tailoring medical preventative strategies to the time of year may be helpful.
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Calcio/orina , Cálculos Renales/orina , Vitamina D/orina , Femenino , Humanos , Cálculos Renales/etiología , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Estaciones del Año , UrinálisisRESUMEN
INTRODUCTION: Struvite stones account for 15% of urinary calculi and are typically associated with urease-producing urinary tract infections and carry significant morbidity. This study aims to characterize struvite stones based on purity of stone composition, bacterial speciation, risk factors, and clinical features. METHODS: Retrospective data was collected from patients diagnosed with infection stones between 2008 and 2012. Stone analysis, perioperative urine cultures, bacterial speciation, and clinical data were collected and analyzed. The purity of struvite stones was determined. Statistical comparisons were made among homogeneous and heterogeneous struvite stones. RESULTS: From the four participating centres, 121 struvite stones were identified. Only 13.2% (16/121) were homogenous struvite. Other components included calcium phosphate (42.1%), calcium oxalate (33.9%), calcium carbonate (27.3%), and uric acid (5.8%). Partial or full staghorn calculi occurred in 23.7% of cases. Urease-producing bacteria were only present in 30% of cases. Proteus, E. coli, and Enterococcus were the most common bacterial isolates from perioperative urine, and percutaneous nephrolithotomy was the most common modality of treatment. Only 40% of patients had a urinalysis that was nitrite-positive, indicating that urinalysis alone is not reliable for diagnosing infection stones. The study's limitation is its retrospective nature; as such, the optimal timing of cultures with respect to stone analysis or treatment was not always possible, urine cultures were often not congruent with stone cultures in the same patient, and our findings of E. coli commonly cultured does not suggest causation. CONCLUSIONS: Struvite stones are most often heterogeneous in composition. Proteus remains a common bacterial isolate; however, E. coli and Enterococcus were also frequently identified. This new data provides evidence that patients with struvite stones can have urinary tract pathogens other than urease-producing bacteria, thus challenging previous conventional dogma.
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PURPOSE: Preoperative determination of uric acid stones from computerized tomography imaging would be of tremendous clinical use. We sought to design a software algorithm that could apply data from noncontrast computerized tomography to predict the presence of uric acid stones. MATERIALS AND METHODS: Patients with pure uric acid and calcium oxalate stones were identified from our stone registry. Only stones greater than 4 mm which were clearly traceable from initial computerized tomography to final composition were included in analysis. A semiautomated computer algorithm was used to process image data. Average and maximum HU, eccentricity (deviation from a circle) and kurtosis (peakedness vs flatness) were automatically generated. These parameters were examined in several mathematical models to predict the presence of uric acid stones. RESULTS: A total of 100 patients, of whom 52 had calcium oxalate and 48 had uric acid stones, were included in the final analysis. Uric acid stones were significantly larger (12.2 vs 9.0 mm, p = 0.03) but calcium oxalate stones had higher mean attenuation (457 vs 315 HU, p = 0.001) and maximum attenuation (918 vs 553 HU, p <0.001). Kurtosis was significantly higher in each axis for calcium oxalate stones (each p <0.001). A composite algorithm using attenuation distribution pattern, average attenuation and stone size had overall 89% sensitivity, 91% specificity, 91% positive predictive value and 89% negative predictive value to predict uric acid stones. CONCLUSIONS: A combination of stone size, attenuation intensity and attenuation pattern from conventional computerized tomography can distinguish uric acid stones from calcium oxalate stones with high sensitivity and specificity.
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Oxalato de Calcio , Tomografía Computarizada por Rayos X/métodos , Ácido Úrico , Cálculos Urinarios/diagnóstico por imagen , Adulto , Anciano , Algoritmos , Diagnóstico Diferencial , Humanos , Persona de Mediana Edad , Modelos Biológicos , Estudios Retrospectivos , Sensibilidad y Especificidad , Programas Informáticos , Cálculos Urinarios/químicaRESUMEN
ABSTRACT Background: With a high rate of recurrence, urolithiasis is a chronic disease that impacts quality of life. The Patient Reported Outcomes Measurement Information System is an NIH validated questionnaire to assess patient quality of life. We evaluated the impact of urolithiasis on quality of life using the NIH-sponsored PROMIS-43 questionnaire. Materials and Methods: Patients reporting to the kidney stone clinic were interviewed to collect information on stone history and demographic information and were asked to complete the PROMIS-43 questionnaire. Quality of life scores were analyzed using gender and age matched groups for the general US population. Statistical comparisons were made based on demographic information and patient stone history. Statistical significance was P<0.05. Results: 103 patients completed the survey. 36% of respondents were male, the average age of the group was 52 years old, with 58% primary income earners, and 35% primary caregivers. 7% had never passed a stone or had a procedure while 17% passed 10 or more stones in their lifetime. Overall, pain and physical function were worse in patients with urolithiasis. Primary income earners had better quality of life while primary caregivers and those with other chronic medical conditions were worse. Patients on dietary and medical therapy had better quality of life scores. Conclusions: Urolithiasis patients subjectively have worse pain and physical function than the general population. The impact of pain on quality of life was greatest in those patients who had more stone episodes, underscoring the importance of preventive measures. Stone prevention measures improve quality of life.