Does displacement of lower pole stones during retrograde intrarenal surgery improves stone-free status?: a systematic review and meta-analysis

Purpose: Kidney stones are one of the most common urological diseases worldwide. The size and location of the stone are the most important factors in determining the most suitable treatment options. The aim of this review was to evaluate the displacement of lower pole stones. Methods: Three studies assessing the efficacy of translocating kidney stones from the lower pole of the kidney to other locations during retrograde intrarenal surgery published in the last 20 years were included. A systematic search was conducted in the PubMed, Embase, Latin American and Caribbean Health Sciences Literature (LILACS), and Web of Science databases using the following search terms: "Lower pole," "Lithotripsy." Meta-analysis was performed using Review Manager version 5.4. Results: Stone-free rates were improved through displacement (odds ratio - OR = -0.15; 95% confidence interval-95%CI -0.24--0.05; p = 0.002; I2 = 21%), but at the cost of increased surgical duration (mean difference = -12.50; 95%CI -24.06--0.95; p = 0.03; I2 = 94%). Although this represents a potentially negative outcome, the improvement in clearance rates justifies the additional investment of time and effort. Conclusions: Displacement of lower pole kidney stones for subsequent lithotripsy brings significant benefits in terms of stone-free rate, with no difference in laser energy usage. However, it results in increased surgical time. Despite these factors, the benefits to patients undergoing the procedure are substantial.

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.

Contemporary considerations in the management and treatment of lower pole stones

ABSTRACT The presence of lower pole stones poses a unique challenge due to the anatomical considerations involved in their management and treatment. Considerable research has been performed to determine the optimal strategy when faced with this highly relevant clinical scenario. Standard options for management include observation, shock wave lithotripsy, retrograde intrarenal surgery, or percutaneous nephrolithotomy. Indeed, each approach confers a distinct set of risks and benefits, which must be placed into the context of patient preference and expected outcomes. The current state of practice reflects a combination of lessons learned from managing calculi not only in the lower pole, but also from other locations within the kidney as well.

Mini-percutaneous nephrolithotomy in a child with multiple urogenital anomalies and a solitary duplex kidney

ABSTRACT Purpose: To report a case of successful removal of right staghorn renal calculi in a 3-year-old girl with Arnold-Chiari malformation and multiple urogenital anomalies. Case report: A 3-year-old female child with the diagnosis of Arnold-Chiari type 2 malformation was referred to our clinic due to presence of 9 kidney stones with a total volume of 10743mm3. The total of the longest diameters of all stones was calculated as 11.4cm. The patient had a urogenital septum, bifid bladder, and duplicated collecting system on the right side. An 18F Amplatz sheath was placed and mini-percutaneous nephrolithotomy was performed successfully by laser and pneumatic lithotripter. Any residual urinary tract stones or urinary tract infection were not detected during the 6th-month follow-up. Conclusion: Urolithiasis requires a thorough understanding of the underlying causes, as well as an effective and minimally invasive treatment. It is important for urologists to understand the complexity of the optimal stone management in pediatric patients in order to maximize treatment efficacy and minimize morbidity. We conclude that it is essential to treat urolithiasis in a single session in children with urogenital anomalies and accompanying congenital anomalies who have past surgical history.

Comparison of long-term outcomes in different managements of diverticular neck in percutaneous nephrolithotomy for diverticular calculi / 北京大学学报(医学版)

OBJECTIVE@#To compare the short-term effects and long-term outcomes of incisional procedure and dilatation procedure to manage diverticular neck in percutaneous nephrolithotomy for diverticular stones.@*METHODS@#Clinical data of 61 patients with diverticular stones who underwent percutaneous nephrolithotomy from June 2009 to January 2019 were retrospectively collected and analyzed, which was as follous: (1) basic information: age, gender, body mass index (BMI), American Society of Anesthesiology (ASA) classifications and preoperative symptoms.(2)stone characteristic and procedure-related data: location and size of stone, skinned renal access length and procedure time.(3)perioperative clinical data: hemoglobin drop, Clavien's classification and stone-free rate. Long-term follow-ups were performed for more than 5 years after the patients were discharged.@*RESULTS@#Fifty-three patients were included based on the inclusion and exclusion criteria, and were divided into the dilation group (n=37) and the incision group (n=16) by the treatment methods of diverticular neck. There were 24 male patients (45.3%) and 29 female patients (54.7%), with a mean age of 39.96±12.88 years. Stones were mainly located in the upper pole (n=32, 60.38%) and posterior area (n=41, 77.4%), with a predominance of single stone (n=36, 67.9%). There was no statistically significant difference in demographic data and stone characteristics between the two groups except for age and stone burden. Forty-five patients (84.9%) reached stone-free status after surgeries, and 44 patients (83.0%) postoperative symptoms improved. Twelve patients were lost to the follow-ups, and 41 cases were followed up for an average of 77 months. One recurrence occurred 1 year after surgery. Fifteen patients underwent operations within the past 5 years and the overall 5-year recurrence rate for the remaining 26 patients was 34.6%. There was no statistically significant difference in the incidence of perioperative complications, postoperative stone-free rate and recurrence rate between the two groups, and the recurrence rate was significantly higher 5 years postoperatively than 1 year postoperatively. The proportion of the patients who remained lithotripsy-free and residual stone status decreased significantly.@*CONCLUSION@#Both incisional and dilatation procedures in percutaneous nephrolithotomy to manage diverticular neck could bring the satisfactory postoperative stone free rate. The recurrence rate was about 30% to 40% 5 years after surgery.

Urolithiasis and sleeve gastrectomy: a prospective assessment of urinary biochemical variables / Urolitíase e gastrectomia vertical: uma avaliação prospectiva das variáveis bioquímicas urinárias

ABSTRACT Introduction: to evaluate urinary biochemical alterations related to urolithogenesis processes after sleeve gastrectomy (SG). Materials and methods : prospective study with 32 individuals without previous diagnosis of urolithiasis who underwent SG. A 24-h urine test was collected seven days prior to surgery and at 6-month follow-up. The studied variables were urine volume, urinary pH, oxalate, calcium, citrate, and magnesium and calcium oxalate super saturation (CaOx SS). Results: patients were mainly women (81.2%), with mean age of 40.6 years. Mean pre- and postoperative BMI were 47.1 ± 8.3 Kg/m2 and 35.5 ± 6.1 Kg/m2, respectively (p<0.001). Urine volume was significantly lower at the postoperative evaluation in absolute values (2,242.50 ± 798.26 mL x 1,240.94 ± 352.39 mL, p<0.001) and adjusted to body weight (18.58 ± 6.92 mL/kg x 13.92 ± 4.65 mL/kg, p<0.001). CaOx SS increased significantly after SG (0.11 ± 0.10 x 0.24 ± 0.18, p<0.001). Moreover, uric acid levels were significantly lower at the postoperative evaluation (482.34 ± 195.80 mg x 434.75 ± 158.38 mg, p=0.027). Urinary pH, oxalate, calcium, citrate, and magnesium did not present significant variations between the pre- and postoperative periods. Conclusion: SG may lead to important alterations in the urinary profile. However, it occurs in a much milder way than that of RYGB.

RESUMO Introdução: avaliar as alterações bioquímicas urinárias relacionadas aos processos de litíase urinária após gastrectomia vertical (GV). Método: estudo prospectivo, com 32 indivíduos submetidos a GV, sem diagnóstico prévio de urolitíase. Foi coletada urina de 24 horas, sete dias antes da operação e no retorno de 6 meses. As variáveis estudadas foram volume de urina, pH urinário, oxalato, cálcio, citrato e super saturação de oxalato e cálcio (SS CaOx). Resultados: os pacientes foram em sua maioria mulheres (81,2%), com idade média de 40,6 anos. O IMC médio pré e pós-operatório foi 47,1 ± 8,3 Kg/m2 e 35,5 ± 6,1 Kg/m2, respectivamente (p<0,001). O volume de urina foi significativamente baixo na avaliação pós-operatória em valores absolutos (2.242,50 ± 798,26 mL versus 1.240,94 ± 352,39 mL, p<0,001) e ajustado ao peso corporal (18,58 ± 6,92 mL/kg versus 13,92 ± 4,65 mL/kg, p<0,001). A SS CaOx aumentou significativamente após a GV (0,11 ± 0,10 versus 0,24 ± 0,18, p<0,001). Além disso, os níveis de ácido úrico apresentaram-se significativamente baixos na avaliação pós-operatória (482,34 ± 195,80 mg versus 434,75 ± 158,38 mg, p=0,027). PH urinário, oxalato, cálcio, citrato e magnésio não apresentaram variações significativas entre os períodos pré e pós-operatório. Conclusão: a GV pode levar a alterações importantes no perfil urinário. Entretanto, essas ocorrem de forma muito mais leve que na derivação gástrica em Y de Roux.

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.

Factors affecting fluoroscopy time during percutaneous nephrolithotomy: Impact of stone volume distribution in renal collecting system

ABSTRACT Purpose: To identify the factors increased fluoroscopy time during percutaneous nephrolithotomy and investigate the relationship between the 3D segmentation volume ratio of stone to renal collecting system and fluoroscopy time. Materials and Methods: Data from 102 patients who underwent percutaneous nephrolithotomy were analyzed retrospectively. Volume segmentation of both the renal collecting system and stones were obtained from 3D segmentation software with the images on CT data. Analyzed stone volume (ASV), renal collecting system volume (RCSV) measured and the ASV-to-RCSV ratio was calculated. Several parameters were evaluated for their predictive ability with regard to fluoroscopy time. Results: The stone-free rate was 55.9% after the percutaneous nephrolithotomy. Complications occurred in 31(30.4%) patients. The mean fluoroscopy time was 199.4±151.1 seconds. The fluoroscopy time was significantly associated with the ASV-to-RCSV ratio (p<0.001, r=0.614). The single tract was used in 77 (75.5%) cases while multiple tracts were used in 25 (24.5%) cases. Fluoroscopy time was significantly associated with multiple access (p<0.001, r=0.689). On univariate linear regression analysis, longer fluoroscopy time was related with increased stone size, increased stone volume, increased number of access, increased calyx number with stone, increased ASV-to-RCSV, increased operative time and decreased stone essence. On multivariate linear regression analysis, the number of access and the ASV-to-RCSV were independent predictors of fluoroscopy time during percutaneous nephrolithotomy. Conclusions: The distribution of the stone burden volume in the pelvicalyceal system is a significant predictor for prolonged fluoroscopy time during percutaneous nephrolithotomy. Measures to decrease FT could be beneficial in patients with a high ASV-to-RCSV ratio for precise preoperative planning.

3D Reconstruction and physical renal model to improve percutaneous punture during PNL

ABSTRACT Introduction and Objectives: We aim to present the use of 3D digital and physical renal model (1-5) to guide the percutaneous access during percutaneous nephrolithotripsy (PNL). Materials and Methods: We present the clinical case of a 30 years old man with left renal stone (25x15 mm). A virtual 3D reconstruction of the anatomical model including the stone, the renal parenchyma, the urinary collecting system (UCS) and the skeletal landmarks (lumbar spine and ribs) was elaborated. Finally, a physical 3D model was created with a 3D printer including the renal parenchyma, UCS and the stone. The surgeon evaluated the 3D virtual reconstruction and manipulated the printed model before surgery to improve the anatomical knowledge and to facilitate the percutaneous access. In prone position, combining ultrasound and fluoroscopy implemented by the preoperative anatomical planning based on the 3D virtual and printed model, an easy and safe access of the inferior calyx was achieved. Then, the patient underwent PNL using a 30 Fr Amplatz sheet with semi-rigid nephroscope and ultrasound energy to achieve a complete lithotripsy of the pelvic stone. Results: The procedure was safely completed with 1 single percutaneous puncture (time of puncture 2 minutes). Overall surgical time was 90 min. No intra and postoperative complications were reported. The CT scan performed before discharge confirmed a complete stone free state. Conclusion: The 3D-guided approach to PNL facilitates the preoperative planning of the puncture with better knowledge of the renal anatomy and may be helpful to reduce operative time and improve the learning curve.

Two-shift operation mode can improve the efficiency and comfort of flexible ureteroscopic holmium laser lithotripsy for the treatment of renal calculi larger than 1. 5cm

ABSTRACT Purpose: To compare two-shift operation mode and single player mode different impact on surgical results and operator comfort in flexible ureteroscopic holmium laser lithotripsy for renal calculi larger than 1.5cm. Materials and Methods: From december 2017 to december 2018, 92 patients with renal calculi admitted to Qilu Hospital and were treated through flexible ureteroscopy. They were randomized in two-shift group (n=50) and single player group (n=42). The operative time, blood loss, hospitalization stay after operation, residual fragments (≥4mm) rate, fragmentation speed, postoperative complications and operator's fatigue score were compared. Results: There was no significant difference between two groups regarding age, gender, illness side, stone size, blood loss, operative time, postoperative hospitalization stay, complications, etc (p >0.05). The fragmentation speed was 44.5±20.0mm3/min in two-shift group compared with 34.2±17.3mm3/min in single player group (p=0.037). Residual fragments (≥4mm) rate after first surgery was 18% in two-shift group, while the residual fragments (≥4mm) rate was 40.5% after first surgery in single player group (p=0.017). The total fatigue score of two-shift group was 8.4 compared to 29.9 in single player group (p <0.001). Conclusion: In flexible ureteroscopic holmium laser lithotripsy for the treatment of renal calculi larger than 1.5cm, two-shift operation mode can raise the fragmentation speed and stone clearance rate, as well as significantly lower operator's fatigue level and improve operator's comfort.

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.

The role of a novel decision aid to support informed decision making process in patients with a symptomatic non - lower pole renal stone < 20 mm in diameter: a prospective randomized study

ABSTRACT Objectives To evaluate the efficacy of a novel decision aid (DA) in improving the patients' level of knowledge and decreasing decisional conflicts while deciding for SWL vs. RIRS in case of a symptomatic renal stone <2 cm. Materials and Methods In this prospective randomized study patients were randomized to receive either standard informing process (group 1, n=57) or DA (group 2, n=58). Level of knowledge was assessed with a questionnaire of 10 questions before and after patient informing process. Level of decisional conflict was assessed with a previously validated scoring system. Logistic regression analysis was performed to identify factors associated with adequate level of knowledge. Results Level of knowledge increased significantly in both groups after patient informing process. The increase was significantly more prominent in group 2 (p=0.045). Percentage of patients with adequate knowledge was also higher in group 2 (56.1%vs.74.1%, p=0.04). Mean decisional conflict scale score (higher score indicates higher decisional conflict level) was also significantly higher in group1 (14.7±14.5 vs. 10.1±13.7, p=0.045). Multivariate logistic regression analysis revealed higher education level (college degree) and use of DA as factors associated with adequate level of knowledge. Conclusions In the current study, The DA was shown to have a positive impact on level of knowledge and diminish the level of decisional conflict for patients with a symptomatic non-lower pole renal stone <20 mm. We recommend development and use of DAs for particular clinic scenarios to aid in education of patients and shared decision making process in stone disease clinics.

Comparison of supine and prone miniaturized percutaneous nephrolithotomy in the treatment of lower pole, middle pole and renal pelvic stones: A matched pair analysis

ABSTRACT Purpose We aimed to compare the outcomes of supine and prone miniaturized percutaneous nephrolithotomy (m-PNL) in the treatment of lower pole, middle pole and renal pelvic stones. Materials and Methods 54 patients who performed supine m-PNL between January 2017 and March 2018 and 498 patients who performed prone m-PNL between April 2015 and January 2018 were included in the study. Of the 498 patients, 108 matching 1: 2 in terms of age, gender, body mass index, American Association of Anesthesiology score, stone size, stone localization and hydronephrosis according to the supine m-PNL group were selected as prone m-PNL group. The patients with solitary kidney, upper pole stone, urinary system anomaly or skeletal malformation and pediatric patients (<18 years old) were excluded from the study. The success was defined as 'complete stone clearance' and was determined according to the 1st month computed tomography. Results The operation time and fluoroscopy time in supine m-PNL was significantly shorter than prone m-PNL group (58.1±45.9 vs. 80.1±40.0 min and 3.0±1.7 min vs. 4.9±4.5 min, p=0.025 and p=0.01, respectively). When post-operative complications were compared according to the modified Clavien-Dindo classification, overall and subgroup complication rates were comparable between groups. There was no significant difference between the groups in terms of the success rates (supine m-PNL; 72.2%, prone m-PNL; 71.3%, p=0.902). Conclusions Supine m-PNL procedure is more advantageous in terms of operation time and fluoroscopy time in the treatment of lower pole, middle pole and renal pelvic stones.