One week pre-operative oral antibiotics for percutaneous nephrolithotomy reduce risk of infection: a systematic review and meta-analysis

ABSTRACT Purpose The aim of this meta-analysis is to assess the efficacy of extended dose of preoperative antibiotics to reduce infectious risk in patients undergoing percutaneous nephrolithotomy (PCNL). Materials and Methods A literature search for prospective case-control studies or randomized controlled trials was done. PICO framework was used. Population: adult patients that underwent to PCNL; Intervention: extended dose preoperative antibiotic prophylaxis before PCNL; Control: short dose preoperative antibiotic prophylaxis before PCNL; and Outcome: systemic inflammatory response syndrome (SIRS) or sepsis, fever after PCNL and positive intraoperative urine and stone culture. This meta-analysis was registered in PROSPERO database under the number: CRD42022359589. Results Three RCT and two prospective studies (475 patients) were included. SIRS/sepsis outcome was retrieved from all studies included. Seven days preoperative oral antibiotics for PCNL was a protective factor for developing SIRS/sepsis (OR 0.366, 95% CI 0.234 - 0.527, p < 0.001). There was no statistical association between seven-day use of antibiotics and fever (OR 0.592, 95% CI 0.147 - 2.388, p = 0.462). Patients who received seven days preoperative antibiotics had lower positive intraoperative urine culture (OR 0.284, 95% CI 0.120 - 0.674, p = 0.004) and stone culture (OR 0.351, 95% CI 0.185 - 0.663, p = 0.001) than the control group. Conclusion one week of prophylactic oral antibiotics based on local bacterial sensitivity pattern plus a dose of intravenous antibiotics at the time of surgery in patients undergoing PCNL reduces the risk of infection.

Factors associated with complications after percutaneous nephrolithotomy: an analysis of 1,066 cases

SUMMARY OBJECTIVE: The aim of this study was to identify predictive factors for complications after percutaneous nephrolithotomy. METHODS: We prospectively analyzed patients who underwent percutaneous nephrolithotomy from June 2011 to October 2018. The association of preoperative and intraoperative factors with the presence of complications was assessed using univariate and multivariate analyses. The significance level was set at p<0.05. RESULTS: A total of 1,066 surgeries were evaluated, and the overall complication rate was 14.9%. In all, 105 (9.8%) surgeries were performed in the prone position, and 961 (90.2%) were performed in the supine position. Univariate analysis demonstrated that surgical position, upper pole puncture, surgical time, number of tracts, and Guys Stone Score were associated with complications. In multivariate analyses, prone position (odds ratio [OR] 2.10; p=0.003), surgical time ≥90 min (OR 1.76; p=0.014), upper pole puncture (OR 2.48; p<0.001), and Guys Stone Score 3 or 4 (OR 1.90; p=0.033) were independent predictive factors for complications after percutaneous nephrolithotomy. CONCLUSION: Performing percutaneous nephrolithotomy in the supine position, in under 90 min, and avoiding upper pole punctures may reduce complications during the treatment of large kidney stones.

Comparison of the outcomes of flexible ureteroscopy and mini-percutaneous nephrolithotomy for the treatment of kidney stones: a matched-pair analysis

SUMMARY OBJECTIVE: Mini-percutaneous nephrolithotomy is a recent advancement in the field of kidney stone treatment; however, its role has not been completely established. We aimed to compare the outcomes of initial Mini-percutaneous nephrolithotomy and flexible ureteroscopy. METHODS: A retrospective review of consecutive mini-percutaneous procedures was performed. Inclusion criteria were as follows: all percutaneous nephrolithotomy procedures performed with an access sheath up to 24Fr, kidney stone burdens up to 1550 mm3; and the presence of postoperative computed tomography (for control). The data collected for Mini-percutaneous nephrolithotomy procedures were paired 1:2 with patients treated with flexible ureteroscopy for stones between 100 and 1550 mm3, and with postoperative computed tomography for control. A 14Fr Mini-percutaneous nephrolithotomy set was used. The stone-free rate was defined as the absence of fragments on the control computed tomography, whereas success was limited to 2-mm residual fragments. Statistical analysis was performed using SPSS version 19. RESULTS: A total of 63 patients met the inclusion criteria (42 with flexible ureteroscopy and 21 with mini-percutaneous nephrolithotomy). Demographic data were comparable. The stone-free rate and success were similar between the groups (76.2 vs. 66.7%, p=0.42 and 90.5 vs. 85.7%, p=0.57). The complication rate was also similar (26.1 vs. 9.6%, p=0.188), but Mini-percutaneous nephrolithotomy had longer hospitalization and fluoroscopy time (p=0.001 in both). CONCLUSIONS: Our initial study of Mini-percutaneous nephrolithotomy showed that it is a promising procedure, with outcomes similar to flexible ureteroscopy, but with higher inpatient numbers and fluoroscopy times. A larger study population size and better equipment may improve the outcomes of mini-percutaneous nephrolithotomy.

Ultrasound guided endoscopic combined Intrarenal surgery - 10 steps for the success

ABSTRACT Background: Endoscopic combined intrarenal surgery (ECIRS) has been used to treat complex kidney stones (1). The combined use of ultrasound (US) has the potential to improve safety and reduce radiation exposure, however, it is still underutilized (2). Objectives: Our objective is to describe, in a step-by-step manner, the ultrasound-guided ECIRS (USG ECIRS) technique, in order to facilitate learning by urologists. Materials and Methods: We describe the 10 standardized steps that we recommend to achieve a good outcome, based on our previous experience on a high-volume kidney stone center. We recorded a case of a 37-year-old female patient with complex bilateral kidney stones that underwent a left simultaneous combined retrograde and antegrade approach. The 10 described steps are: 1 - case evaluation with CT scan (3); 2 - preoperative care with antibiotics and tranexamic acid; 3 - warm-up and training with phantoms; 4 - patient positioning in Barts flank free position; 5 - retrograde nephroscopy with flexible ureteroscope; 6 - US and endoscopic guided puncture; 7 - tract dilation under endoscopic view; 8 - stone fragmentation; 9 - status free checking and 10, kidney drainage. Images were captured by external and internal cameras, promoting a complete understanding of the procedure. The patient has signed a written informed consent form. Results: Puncture was achieved under US guidance with one attempt. Another puncture was necessary in the lower pole, parallel to the initial puncture, due to a large fragment. Surgical time was 140 min. Stone-free status was verified by retrograde and antegrade view. Kidney drainage was done with ureteral stent on string, removed after 7 days. Hb drop was 1.1 Hb/dL. The first postoperative day CT scan showed no residual stones and no complications. The patient was discharged after the CT and urethral catheter removal. Conclusion: The USG ECIRS seems to be a very efficient and reproducible technique for the treatment of complex kidney stones. Its use should be widespread.

Single-use flexible ureteroscopes: update and perspective in developing countries. A narrative review

ABSTRACT Flexible ureteroscopy is a well-established method for treatment of urinary stones but flexible ureteroscopes are expensive and fragile devices with a very limited lifetime. Since 2006 with the advent of digital flexible ureteroscopes a great evolution has occurred. The first single-use flexible ureteroscope was launched in 2011 and new models are coming to the market. The aim of this article is to review the characteristics of these devices, compare their results with the reusable devices and evaluate the cost-benefits of adopting single-use flexible ureteroscopes in developing countries. Materials and Methods: an extensive review of articles listed at PubMed and published between 2000 and 2021 was performed. Results: Single-use flexible ureteroscopes have a shaft with 65 to 68cm length and weight between 119 and 277g. Their deflection goes up to 300 degrees. Their stone-free rates vary between 60 and 95% which is comparable to reusable scopes and operative times ranges from 54 to 86 minutes which are lower when compared to reusable flexible scopes. Their costs vary between 800 and 3180 US dollars. Conclusion: single-use flexible ureteroscopes are lighter and have superior quality of image when compared to fiberoptic ones. There are no definite data showing a higher stone-free rate or less complications with the use of single-use flexible ureteroscopes. Each institution must perform a cost-benefit analysis before making the decision of adopting or not such devices depending on the local circumstances.

Predictive factors for success after supine percutaneous nephrolithotomy: an analysis of 961 patients

SUMMARY OBJECTIVE: The aim of this study was to evaluate the predictive factors for success following percutaneous nephrolithotomy in the supine position. METHODS: Patients who underwent percutaneous nephrolithotomy in the supine position from June 2011 to October 2018 were evaluated. Age, sex, body mass index, the American Society of Anesthesiologists physical status classification, hemoglobin level, number of previous surgeries, stone size, and the Guy's Stone Score were analyzed. Success was considered if no fragments were observed on the computed tomography scan on the first postoperative day. Univariate and multivariate analyses were performed to determine significant parameters. RESULTS: We evaluated 961 patients; of them, 483 (50.2%) underwent previous stone-related surgery, and 499 (51.9%) had Guy's Stone Score 3 or 4. The overall success rate in a single procedure was 40.7%, and complication rate was 13.7%. The univariate analysis showed that the maximum diameter of the stone (25.10±10 mm; p<0.001), previous percutaneous nephrolithotomy (OR 0.52; p<0.001), number of previous percutaneous nephrolithotomy (OR 0.15; p<0.001), the Guy's Stone Score (OR 0.28; p<0.001), and the number of tracts (OR 0.32; p<0.001) were significant. In the multivariate analysis, the number of previous percutaneous nephrolithotomy (OR 0.54; p<0.001) and the Guy's Stone Score (OR 0.25; p<0.001) were statically significant. CONCLUSIONS: Guy's Stone Score and the number of previous percutaneous nephrolithotomy are predictors of success with the supine position. Complex cases and with previous percutaneous interventions may require technical improvements to achieve higher stone-free rates.

Effect of a low-calorie diet on 24-hour urinary parameters of obese adults with idiopathic calcium oxalate kidney stones

ABSTRACT Purpose: to evaluate the effect of low-calorie diet on 24-hour urinary metabolic parameters of obese adults with idiopathic calcium oxalate kidney stones. Materials and Methods: Adult idiopathic calcium oxalate stone formers, with body mass index (BMI) ≥30kg/m2 and a known lithogenic metabolic abnormality, were submitted to low-calorie diet for twelve weeks. After enrolment, anthropometric measures, serum exams, 24-hour urinary metabolic parameters and body impedance were collected one month prior to dietary intervention and at the end of twelve weeks. Correlations between weight loss, waist circumference loss, fat loss and variation in 24-hour urinary lithogenic parameters and calcium oxalate urinary supersaturation (CaOx SS) as per Tiselius equation were analysed. Results: From January 2017 to January 2018, 39 patients were enrolled to participate in this study. Median (range) prescribed diet was 1300 (1100-2100) Kcal/day. Mean age was 51.7±11.0 (29-68) years old and 69.2% were female. 30.8% of the participants shifted from obesity to BMI <30kg/m2 and none to BMI <25kg/m2. A significant correlation was found between baseline 24-hour urinary oxalate and weight (p=0.018) and BMI (p=0.026). No correlation was found between variation of weight, waist circumference, fat mass and 24-h urinary stone risk factors or CaOx SS. Conclusions: Short-term modest weight loss induced by twelve weeks of low-calorie diet is not associated with a decrease of 24-hour urinary lithogenic parameters in idiopathic calcium oxalate stone formers. Calcium oxalate urinary stone formation is probably multifactorial and driven by other factors than weight.

Does previous standard percutaneous nephrolithotomy impair retrograde intrarenal surgery outcomes?

ABSTRACT Purpose: The objective of this study is to evaluate the impact of a previous standard percutaneous nephrolithotomy (PCNL) on the outcomes of retrograde intrarenal surgery (RIRS). Materials and Methods: Outcomes of RIRS performed from January 2017 to January 2020 in adult patients with residual stone fragments ≤20mm after a standard PCNL (Post-PCNL) and symptomatic adult patients with kidney stones ≤20mm (Control) were prospectively studied. Stone-free rate (SFR) was evaluated on a postoperative day 90 non-contrast computed tomography. Surgical complications based on Clavien-Dindo classification during the 90 days of follow-up were recorded. Results: Outcomes of 55 patients and 57 renal units of the post-PCNL group were compared to 92 patients and 115 renal units of the control group. SFR was lower in post-PCNL group than in control (28/57, 49.1% vs. 86/115, 74.8%, p <0.001). Overall complications were more frequent in post-PCNL group (p=0.004). Infundibula strictures were identified and incised with laser in 15/57 (26.3%) renal units of the post-PCNL group. Thirteen renal units had infundibulum stricture at the site of previous percutaneous tract (13/15; 86.7%, p=0.004) and one renal unit had three infundibula strictures. Postoperative complications were not affected by the treatment of infundibula strictures (p=0.198). Conclusions: Previous standard PCNL significantly impairs the outcomes of RIRS. Infundibula strictures can be found in 26.3% of the patients with residual stone fragments after standard PCNL for large burden kidney stones. The main site of infundibulum stricture after standard PCNL is the infundibulum of the entry calyx.

Comparing public interest on stone disease between developed and underdeveloped nations: are search patterns on google trends similar?

ABSTRACT Objective: The big data provided by Google Trends may reveal patterns in health information-seeking behavior on population from Brazil and United States (US). Our objective was to explore and compare patterns of stone disease online information-seeking behaviors in both nations. Materials and Methods: To compare Relative Search Volume (RSV) among different urologic key words we chose "US" and "Brazil" as country and "01/01/2009 - 31/12/2018" as time-range. The final selection included 12 key words in each language. We defined "ureteroscopy" as a reference and compared RSV against it for each term. RSV was adjusted by the reference and normalized in a scale from 0-100. Trend presence was evaluated by Mann Kendall Test and magnitude by Sen's Slope (SS) Estimator. Results: We found an upward trend (p <0.01) in most of the researched terms in both countries. Higher temporal trends were seen for "Kidney Stone" (SS=0.36), "Kidney Pain" (SS=0.39) and "Tamsulosin" (SS=0.21) in the US. Technical treatment terms had little search volumes and no increasing trend. "Kidney Stent" and "Double J" had a significant increase in search trend over time and had a relevant search volume overall in 2018. In Brazil, "Calculo Renal", "Colica Renal", "Dor no Rim" and "Pedra no Rim" had a significant increase in RSV (p <0.001). More common and popular terms as "Kidney Stent" and "Tamsulosin" were highly correlated with "Kidney Pain" and "Kidney Stone" in both countries. Conclusions: In the last decade, there was a significant increase in online search for medical information related to stone-disease. Population from both countries tend to look more for generic terms related to symptoms, the disease, medical management and kidney stent, than for technical treatment vocabulary.

Patients with encrusted ureteral stents can be treated by a single session combined endourological approach

ABSTRACT Purpose: To describe our experience in the management of retained encrusted ureteral stents using a single session combined endourological approach. Materials and Methods: Patients with retained encrusted ureteral stents who had been submitted to a single session combined endourological approach from June 2010 to June 2018 were prospectively evaluated. Patients were divided according to the Forgotten-Encrusted-Calcified (FECal) classification. The stone burden, surgical intervention, number of interventions until stone free status, operation time, hospital stay, complications, stone analysis, and stone-free rate were compared between groups. ANOVA was used to compare numerical variables, and the Mann-Whitney or Chi-square test to compare categorical variables between groups. Results: We evaluated 50 patients with a mean follow-up of 2.9±1.4 years (mean±SD). The groups were comparable in terms of age, sex, laterality, BMI, comorbidities, ASA, reason for stent passage, and indwelling time. The stone burden was higher for grades IV and V (p=0.027). Percutaneous nephrolithotomy was the most common procedure (p=0.004) for grades IV and V. The number of procedures until the patients were stone-free was 1.92±1.40, and the hospital stay (4.2±2.5 days), complications (22%), and stone analysis (66% calcium oxalate) were similar between groups. The stone-free rate was lower in grades III to V (60%, 54.5%, and 50%). Conclusions: The endoscopic combined approach in the supine position is a safe and feasible technique that allows removal of retained and encrusted stents in a single procedure. The FECal classification seems to be useful for surgical planning.

The impact of COVID-19 in medical practice. A review focused on Urology

ABSTRACT COVID-19 pandemic is a rapidly spreading virus that is changing the World and the way doctors are practicing medicine. The huge number of patients searching for medical care and needing intensive care beds led the health care system to a burnout status especially in places where the care system was already overloaded. In this setting, and also due to the absence of a specific treatment for the disease, health authorities had to opt for recommending or imposing social distancing to relieve the health system and reduce deaths. All other medical specialties nondirectly related to the treatment of COVID-19 had to interrupt or strongly reduce their activities in order to give room to seriously ill patients, since no one knows so far the real extent of the virus damage on human body and the consequences of doing non deferrable procedures in this pandemic era. Despite not been a urological disease, the urologist needs to be updated on how to deal with these patients and how to take care of himself and of the medical team he works with. The aim of this article is to review briefly some practical aspects of COVID-19 and its implications in the urological practice in our country.

Bilateral simultaneous percutaneous nephrolithotomy versus staged approach: a critical analysis of complications and renal function

SUMMARY INTRODUCTION: Patients with bilateral kidney stones and burdened by large stones are challenging cases for endourologists. Simultaneous bilateral percutaneous nephrolithotomy (sbPCNL) is an option; however, it may be accompanied by important morbidity. An alternative is a staged PCNL, operating one side each time. Herein, we compare the impact of sbPCNL and staged PCNL on complication rates and renal function. METHODS: Patients who underwent sbPCNL or staged bilateral PCNL with a frame time of 6 months were searched in our prospectively collected kidney stone database. Groups were compared for age, gender, body mass index (BMI), comorbidities (classification by the American Society of Anesthesiology - ASA), stone size, Guy's score, stone-free status, renal function, blood loss, blood transfusion rate, complication rate, and length of hospital stay. RESULTS: Twenty-six patients and 52 kidney units were enrolled. The mean operative time was 134.7 min. Only 11.3% of cases had complications, all of them minor (Clavien ≤ 2). Overall, the stone-free rate was 61.50%. Comparing the groups, there was a significantly longer operative time in the sbPCNL group (172.5 vs. 126.3 min; p=0.016), as well as a higher transfusion rate (12.5% vs. 5.6%; p=0.036). There was no statistically significant difference in creatinine levels between the groups. Regarding the stone-free rate, there was a significantly higher proportion of patients in the staged PCNL group (64.9% vs. 43.8%; p=0.012). CONCLUSION: sbPCNL is a safe procedure; however, when compared to staged procedures it has a higher transfusion and lower stone-free rate.

RESUMO INTRODUÇÃO: Paciente com cálculos renais bilaterais e de grande volume são casos desafiadores para os endourologistas. A nefrolitotripsia percutânea bilateral simultânea (NLPbs) é um opção, entretanto esse procedimento pode ser acompanhado de morbidade importante. Uma alternativa é a NLP estagiada, operando um lado de cada vez. Aqui, nós comparamos o impacto da NLPbs e da NLP estagiada nas taxas de complicações e função renal. MÉTODOS: Pacientes que foram submetidos a NLPsb ou NLP stagiada com intervalo de até 6 meses foram pesquisados em nossa base de dados de cálculos renais prospectivamente coletada. Os grupos foram comparados em idade, gênero, índice de massa corpórea (IMC), comorbidades (classificação da Sociedade Americana de Anestesiologia - ASA), tamanho do cálculo, Classificação de Guys, taxa de pacientes livres de cálculos, função renal, perda sanguínea, taxa de transfusão, taxa de complicações e tempo de internação hospitalar. RESULTADOS: Vinte e seis paciente e 52 unidades renais foram incluídas. O tempo operatório médio foi de 134,7 min. Apenas 11.3% dos casos tiveram complicações, sendo todas menores (Clavien ≤ 2). No geral, a taxa de pacientes livres de cálculos foi de 61,5%. Comparando os grupos houve um tempo operatório significativamente maior no grupo NLPbs(172,5 vs. 126,3 min; p=0,016), assim como uma maior taxa de transfusão (12,5% vs. 5,6%; p=0.036). Não houve diferença significante nos níveis de creatinina entre os grupos. Em relação a taxa de doentes livre de cálculos houve uma proporção significativamente maior de pacientes livres de cálculos na NLP estagiada (64,9% vs. 43,8%; p=0,012). CONCLUSÃO: A NLPsb é um procedimento seguro, entretando quando comparada ao procedimento estagiado apresenta uma maior taxa de transfusão e uma menor taxa de pacientes livres de cálculos.

Hemorrhagic complications after percutaneous nephrolithotomy: angiographic diagnosis and management by transcatheter arterial embolization / Complicações hemorrágicas após nefrolitotripsia percutânea: diagnóstico angiográfico e tratamento por embolização arterial transcateter

Abstract Objective: To identify the main hemorrhagic complications after percutaneous nephrolithotomy, as well as the results obtained with transcatheter arterial embolization (TAE) at an interventional radiology center. Materials and Methods: This was a retrospective analysis of patients undergoing TAE for the treatment of hemorrhagic complications after percutaneous nephrolithotomy. All patients underwent computed tomography angiography (CTA). Results: We evaluated a total of nine patients. At emergency department readmission, the most common symptom was macroscopic hematuria, which was seen in five patients. Three patients had an isolated pseudoaneurysm, two had a pseudoaneurysm together with active bleeding (perirenal hematoma), and one had a pseudoaneurysm together with arteriocalyceal fistula. Arteriovenous fistula was diagnosed in three patients and was not seen in combination with other vascular lesions. We did not identify arteriocalyceal fistula in isolation. Five patients underwent TAE with 6 × 15 mm and 6 × 20 mm microcoils. Four patients underwent TAE with n-butyl-2-cyanoacrylate and ethiodized oil. Follow-up CTAs revealed no complications. Conclusion: Because of its high diagnostic accuracy, CTA provides the interventional radiologist with valuable data for individualized therapeutic planning. The TAE procedure is safe and effective. It can therefore be used as a first-line treatment for hemorrhagic complications resulting from percutaneous renal procedures.

Resumo Objetivo: Demonstrar as principais complicações hemorrágicas após nefrolitotripsia percutânea, bem como os resultados após o tratamento por embolização arterial transcateter (EAT) em um centro de radiologia intervencionista. Materiais e Métodos: Coleta e análise de dados retrospectivos de pacientes submetidos a EAT por complicações hemorrágicas após nefrolitotripsia percutânea. Resultados: O sintoma mais comum foi hematúria macroscópica, presente em cinco pacientes no momento da readmissão ao pronto-socorro, e nestes pacientes identificamos três pseudoaneurismas isolados, dois casos de combinação de pseudoaneurisma e sangramento ativo (hematoma perirrenal) e um caso de associação de pseudoaneurisma e fístula arteriocalicinal. Fístula arteriovenosa foi diagnosticada em três pacientes, não sendo observada em associação com outras lesões vasculares. Não identificamos fístula arteriocalicinal isolada, somente associada a pseudoaneurisma. Cinco pacientes foram submetidos a embolização por micromolas 6 × 15 mm e 6 × 20 mm. Quatro pacientes foram submetidos a embolização por Histoacryl e Lipiodol. Não observamos complicações pela angiotomografia computadorizada de controle. Conclusão: A angiotomografia computadorizada apresenta alta acurácia diagnóstica e guarnece o radiologista intervencionista de dados para um planejamento terapêutico individualizado. EAT é um procedimento seguro e eficaz e pode ser utilizado como primeira linha para o tratamento de complicações hemorrágicas resultantes de procedimentos percutâneos renais.

Renal manifestations of sarcoidosis: from accurate diagnosis to specific treatment

ABSTRACT Sarcoidosis is a multisystem granulomatous disease characterized by epithelioid noncaseating granulomas associated with clinical and radiologic findings. The cause of this disease is still uncertain. Sarcoidosis affects mostly lungs and lymph nodes and is not usually considered a urological disease, therefore, this etiology may be overlooked in several urological disorders, such as hypercalcemia, hypercalciuria and nephrolithiasis. It affects all races and genders. This review aims to describe the urological manifestations of sarcoidosis and to elucidate how the disease may affect the management of numerous urological conditions.

Computed tomography window affects kidney stones measurements

ABSTRACT Objectives Measurements of stone features may vary according to the non-contrast computed tomography (NCCT) technique. Using magnified bone window is the most accurate method to measure urinary stones. Possible differences between stone measurements in different NCCT windows have not been evaluated in stones located in the kidney. The aim of this study is to compare measurements of kidney stone features between NCCT bone and soft tissue windows in patients submitted to retrograde intrarenal surgery (RIRS). Materials and Methods Preoperative and 90th postoperative day NCCT were performed in 92 consecutive symptomatic adult patients (115 renal units) with kidney stones between 5 mm to 20 mm (< 15 mm in the lower calyx) treated by RIRS. NCCT were evaluated in the magnified bone window and soft tissue window in three axes in a different time by a single radiologist blinded for the measurements of the NCCT other method. Results Stone largest size (7.92±3.81 vs. 9.13±4.08; mm), volume (435.5±472.7 vs. 683.1±665.0; mm3) and density (989.4±330.2 vs. 893.0±324.6; HU) differed between bone and soft-tissue windows, respectively (p<0.0001) 5.2% of the renal units (6/115) were reclassified from residual fragments > 2 mm on soft tissue window to 0-2 mm on bone window. Conclusion Kidney stone measurements vary according to NCCT window. Measurements in soft tissue window NCCT of stone diameter and volume are larger and stone density is lesser than in bone window. These differences may have impact on clinical decisions.

A comprehensive literature-based equation to compare cost-effectiveness of a flexible ureteroscopy program with single-use versus reusable devices

ABSTRACT Purpose to critically review all literature concerning the cost-effectiveness of flexible ureteroscopy comparing single-use with reusable scopes. Materials and Methods A systematic online literature review was performed in PubMed, Embase and Google Scholar databases. All factors potentially affecting surgical costs or clinical outcomes were considered. Prospective assessments, case control and case series studies were included. Results 741 studies were found. Of those, 18 were duplicated and 77 were not related to urology procedures. Of the remaining 646 studies, 59 were considered of relevance and selected for further analysis. Stone free and complication rates were similar between single-use and reusable scopes. Operative time was in average 20% shorter with digital scopes, single-use or not. Reusable digital scopes seem to last longer than optic ones, though scope longevity is very variable worldwide. New scopes usually last four times more than refurbished ones and single-use ureterorenoscopes have good resilience throughout long cases. Longer scope longevity is achieved with Cidex and if a dedicated nurse takes care of the sterilization process. The main surgical factors that negatively impact device longevity are lower pole pathologies, large stone burden and non-use of a ureteral access sheath. We have built a comprehensive financial cost-effective decision model to flexible ureteroscope acquisition. Conclusions The cost-effectiveness of a flexible ureteroscopy program is dependent of several aspects. We have developed a equation to allow a literature-based and adaptable decision model to every interested stakeholder. Disposable devices are already a reality and will progressively become the standard as manufacturing price falls.

Comparative study of percutaneous nephrolithotomy performed in the traditional prone position and in three different supine positions

ABSTRACT Purpose: To compare the outcomes of percutaneous nephrolithotomy (PCNL) performed in the prone position (PRON) and in three variations of the supine position. Materials and Methods: We performed a retrospective analysis of patients that underwent PCNL at our institution from June 2011 to October 2016 in PRON and in three variations of the supine position: complete supine (COMPSUP), original Valdivia (VALD), and Galdakao - modified Valdivia (GALD). All patients had a complete pre - operative evaluation, including computed tomography (CT). Success was defined as the absence of residual fragments larger than 4 mm on the first post - operative day CT. Results: We analyzed 393 PCNLs: 100 in COMPSUP, 94 in VALD, 100 in GALD, and 99 in PRON. The overall success rate was 50.9% and was similar among groups (p = 0.428). There were no differences between groups in the number of punctures, stone - free rate, frequency of blood transfusions, drop in hemoglobin level, length of hospital stay, and severe complications (Clavien ≥ 3). COMPSUP had a significantly lower operative time than the other positions. COMPSUP had lower fluoroscopy time than VALD. Conclusion: Patient positioning in PCNL does not seem to impact the rates of success or severe complications. However, COMPSUP is associated with a shorter surgical time than the other positions.

Nefrectomia laparoscópica por nefrolitíase: quando é melhor evitar / Laparoscopic nephrectomy for urolithiasis: when is better to avoid it

RESUMO Objetivo: investigar os fatores de risco de conversão para cirurgia aberta na nefrectomia laparoscópica (NL) para urolitíase. Métodos: foram revisados os dados de todos os pacientes maiores de 18 anos de idade submetidos à NL entre janeiro de 2006 e maio de 2013 em nossa Instituição. Índice de Charlson, escore ASA, função renal pela equação e estágio de MDRD (Modification of Diet in Renal Disease), achados de tomografia computadorizada (TC) pré-operatória, complicações pela classificação de Clavien-Dindo e taxa de conversão foram analisados. Determinaram-se os fatores de risco para conversão por meio de regressão logística. Resultados: oitenta e quatro pacientes foram submetidos à LN, sendo que 16 (19%) tiveram seu procedimento convertido para cirurgia aberta devido à forte aderência do hilo renal aos órgãos adjacentes. Outras causas associadas à conversão foram sangramento excessivo (n=6) e lesão do intestino grosso (n=3). Na análise univariada, cirurgia renal prévia, borramento da gordura perirrenal, abscesso renal, abscesso perirrenal, abscesso pararrenal, fístula, aderência ao fígado ou baço e aderência ao intestino foram associados à conversão. Na análise multivariada, abscesso pararrenal e aderência ao intestino foram fatores de risco significativos para a conversão. Conclusão: abscesso pararrenal e aderência ao intestino demonstrados na TC pré-operatória são fatores de risco de conversão para cirurgia aberta em LN por urolitíase.

ABSTRACT Objective: to investigate the risk factors for conversion to open surgery in laparoscopic nephrectomy (LN) for urolithiasis. Methods: we reviewed data on all patients over 18 years of age submitted to LN between January 2006 and May 2013 at our institution. We analyzed the Charlson's index, the ASA score, renal function by the equation and stage of MDRD (Modification of Diet in Renal Disease), preoperative computed tomography (CT) findings, complications by the Clavien-Dindo classification and conversion rate. We used logistic regression analysis to determine the risk factors for conversion. Results: eighty-four patients underwent LN, 16 (19%) sustaining convertion to open surgery due to the strong adhesion of the renal hilum to the adjacent organs. Other causes associated with conversion were excessive bleeding (n=6) and lesion of the large intestine (n=3). In the univariate analysis, previous renal surgery, perirenal fat blurring, renal abscess, perirenal abscess, pararenal abscess, fistula, adherence to the liver or spleen, and adherence to the intestine were associated with conversion. In the multivariate analysis, pararenal abscess and adherence to the intestine were significant risk factors for conversion. Conclusion: pararenal abscess and bowel adhesions demonstrated in the preoperative CT are risk factors for conversion to open surgery in LN due to urolithiasis.