Skin-to-stone Distance Research Articles

Are renal stone protocol computed tomography reports giving us enough information?

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. 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. 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. 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.

Predicting the Efficacy of Repeated Shockwave Lithotripsy for Treating Patients with Upper Urinary Tract Calculi Using an Artificial Neural Network Model.

To establish a prediction model for repeated shockwave lithotripsy (SWL) efficacy to help choose an appropriate treatment plan for patients with a single failed lithotripsy, reducing their treatment burden. The clinical records and imaging data of 304 patients who underwent repeat SWL for upper urinary tract calculi (UUTC) at the Urology Centre of Shiyan People's Hospital between April 2019 and April 2023 were retrospectively collected. This dataset was divided into training (N = 217; 146 males [67.3%] and 71 females [32.7%]) and validation (N = 87; 66 males [75.9%] and 21 females [24.1%]) sets. The overall predictive accuracy of the models was calculated separately for the training and validation. Receiver operating characteristic (ROC) curves were plotted, and the area under the ROC curve (AUC) was calculated. The normalized importance of each independent variable (derived from the one-way analyses) in the input layer of the artificial neural network (ANN) model for the dependent variable (success or failure in repeat SWL) in the output layer was plotted as a bar chart. This study included 304 patients, of whom 154 (50.7%) underwent successful repeat SWL. Predictive models were constructed in the training set and assessed in the validation set. Fourteen influencing factors were selected as input variables to build an ANN model: age, alcohol, body mass index, sex, hydronephrosis, hematuria, mean stone density (MSD), skin-to-stone distance (SSD), stone heterogeneity index (SHI), stone volume (SV), stone retention time, smoking, stone location, and urinary irritation symptom. The model's AUC was 0.852 (95% confidence interval (CI): 0.8-0.9), and its predictive accuracy for stone clearance in the validation group was 83.3%. The order of importance of the independent variables was MSD > SV > SSD > stone retention time > SHI. Establishing an ANN model for repeated SWL of UUTC is crucial for optimizing patient care. This model will be pivotal in providing accurate treatment plans for patients with an initial unsuccessful SWL treatment. Moreover, it can significantly enhance the success rate of subsequent SWL treatments, ultimately alleviating patients' treatment burden.

Can shear wave elastography predict the success of shock‑wave lithotripsy used in renal stones treatment? A prospective study

ObjectiveTo evaluate the usage of shear wave elastography (SWE) in the prediction of the success rate of shock‑wave lithotripsy (SWL) treatment of renal stones.Patients and methodsIn the present study, SWL was performed for 100 patients presented with renal stones in the duration from May 2022 to August 2023. The patients were divided into 2 groups SWL responders and non-responders. The study compared between the 2 groups in terms of baseline parameters of the patients as age, sex, body mass index (BMI), stone size, stone location, stone density (HU), skin-to-stone distance (SSD), the degree of hydronephrosis and the stone elastography values.ResultsThere was no statistically significant relation between stone-free rate and degree of obstruction (p = 0.628), stone size (p = 0.390) upper calyceal location (p = 0.17), middle calyceal location (p = 0.66), and renal pelvis location (p = 1.0). Nevertheless, a statistically significant relation was found as regards lower calyceal location, stone density (HU), and stone Elastography values using multivariate analysis.ConclusionsMeasurement of stone density by shear wave elastography (SWE) can be used as an alternative to HU in decision-making before SWL. SWL success depends mainly on stone site, HU, and SWE values.

Stone Density and Skin to Stone Distance in Non-Contrast Computed Tomography as Prognostic Indicators for the Success of Extra Corporeal Shockwave Lithotripsy in Ureteral Stone Disease

Background Ureteral stones are a major health concern with a worldwide rising prevalence. Ureteral stones formed in the kidney and then descending the ureter commonly manifest themselves as renal colic. Extracorporeal shock wave lithotripsy (ESWL) and ureteroscopy are the two primary treatment modalities for the management of symptomatic ureteral calculi, Aim of the Work In this study we tried to assess the prognostic value of patient and stone characteristics in potential candidates for ESWL in ureteral stones. Patients and Methods We studied the records of 66 patients with upper ureteral calculi who underwent ESWL. We considered patients being stone free (SF) or when < 4 mm fragments were detected. Age, gender, skin to-stone distance, maximum stone length, stone Hounsfield units (HU) were explored in uni- and multivariate regression analysis. Results We found that obesity (BMI > 29.3), high stone density (HU) >935, skin to stone distance >10 and presence of ureteral stent were all factors impeding success of treatment. On the other hand, higher shock intensity and number of shocks per session were positive predictors of treatment success. Conclusion It was concluded that the evaluation of patient and stone characteristics pre ESWL can predict the success of treatment for ureteric stones and we recommend thorough evaluation of the parameters before treatment to determine the best treatment modality for each patient. To date there seems to be value in using these variables to aid in better selecting patients for ESWL and thus improving the efficacy of ESWL. Our study was limited by the number of centers and participants. A wider range of participants would probably achieve more efficient results. Further studies on a larger scale would be better to further validate these results.

Evaluation of Skin to Stone Distance by Non-Contrast Computed Tomography as an Independent Predictor of Stone-Free Rate of Extra-Corporeal Shockwave Lithotripsy for Renal Pelvic Stones

Introduction: Pakistan is situated in the Afro-Asian stone belt. We come across a vast majority of patients having renal calculi. The treatment of renal stones has evolved from open surgery to extracorporeal shock wave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS) in past 20 years. Objective: To determine mean skin to stone distance (SSD) in patients undergoing ESWL for renal pelvic stones and to compare mean SSD between patients with successful ESWL and failed ESWL outcomes for renal pelvic stones. Subjects and Methods: This descriptive case series study was carried out in the Department of Urology, Institute of Kidney Diseases Hayatabad Medical Complex Peshawar from September 2017 to March 2018. A total of 50 patients with renal pelvic stones were enrolled for the study. After consent, non-contrast computed tomography of the kidney ureter and blabber (NCCT KUB) was performed and SSD was measured. All patients underwent ESWL. The patient status either as stone free or having residual stones based on NCCT KUB result was noted on 3rd month. Patients having no stone fragments were defined as stone free and the procedure was defined as successful. Results: The mean age of the patients was 39.02 +/- 12.16 years. 33 (66%) were male and 17 (34%) were female. ESWL was successful in 39 (78%) of patients. 11 (22%) of the patients had residual stones. The mean SSD in patients with successful ESWL outcome was significantly lower than the patients with failed ESWL outcome (10.9 +/- 3.0 vs 14.8 +/- 1.8 cm, p-value = 0.001) Practical Implication: The study results will help the urologists in deciding appropriate treatment modality for patients with renal pelvic stones. Conclusion: We conclude that SSD is lower in patients with successful outcome of ESWL in comparison to those with failed outcome. Therefore pre-treatment NCCT KUB should be used in patients with renal stones to determine the SSD which might predict the outcomes of ESWL. Keywords: Renal calculi, Skin to stone distance, extracorporeal shockwave lithotripsy.

Development and validation of a predictive model for stone-free failure after extracorporeal shockwave lithotripsy in patients with ureteral stone in a large prospective cohort

To develop and validate a nomogram for predicting stone-free failure after shock wave lithotripsy (SWL) guided by ultrasound in patients with ureteral stones. The development cohort consisted of 1698 patients who underwent SWL guided by ultrasound at our center from June 2020 through August 2021. Multivariate unconditional logistic regression analysis was used for building a predictive nomogram with regression coefficients. An independent validation cohort consisted of 712 consecutive patients from September 2020 through April 2021. The performance of the predictive model was assessed in regard to discrimination, calibration, and clinical usefulness. Predictors of stone-free failure included distal stone location (odds ratio = 1.540, P < 0.001), larger stone size (odds ratio = 1.722, P < 0.001), higher stone density (odds ratio = 1.722, P < 0.001), larger skin to stone distance (SSD) (odds ratio = 1.058, P < 0.001), and higher grade of hydronephrosis (odds ratio = 1.755, P = 0.010). For the validation cohort, the model showed good discrimination with an area under the receiver operating characteristic curve of 0.925 (95% confidence interval, 0.898, 0.953) and good calibration (unreliability test, P = 0.412). Decision curve analysis demonstrated that the model was also clinically useful. This study demonstrated that stone location, stone size, stone density, SSD, and hydronephrosis grade were significant predictors of stone-free failure after SWL guided by ultrasound in patients with ureteral stones. This may guide clinical practice.

Is Triple D Score Effective to Predict the Stone-Free Rate After Shockwave Lithotripsy in Pediatric Population.

Triple D score was developed using skin-to-stone distance, stone density, and stone volume for prediction of extracorporeal shockwave lithotripsy (SWL) outcomes in adults. SWL is the first-line treatment method for kidney stones smaller than 2 cm in children however it was not validated in pediatric population. The present paper aims to validate Triple D score in pediatric patients. Of the 269 children treated with SWL between 2007 and 2021, a total of 147 children who had adequate follow-up data and evaluated with non-contrast computed tomography before SWL, were included in the study. Parameters were calculated for each of the stone volume (SV), skin-to-stone distance (SSD), and stone density (SD) variables. Receiver operator characteristic analysis was used to set cut-off values. Triple D scores were calculated, and success rates were determined for each score. Stone-free status was determined as complete clearance after three months of final SWL. The median age of the study group was 7 (range 1 to 16). Ninety-three of the 147 (63%) children had stone-free status. Mean SV, SSD and SD values were significantly higher in SWL failed group than stone-free group after detecting cutoff values of 155 mm3, 6.5 cm, and 550 HU, respectively. Stone-free rates were detected as 23.8%, 35.1%, 74.0%, and 92.0% with the Triple D scores of 0, 1, 2, and 3 points. Our study confirms that Triple D scores supports the SWL outcomes in pediatric population. We believe that our research on Triple D score validation in children is of great clinical importance although various factors may affect to predict the success of SWL.

Non-contrast computed tomography-based factors in predicting ESWL success: A systematic review and meta-analysis.

We assessed the efficacy of some predictive factors that can be measured with non-contrast computed tomography and may affect ESWL success with a systematic review and meta-analysis. All data sources were broadly investigated up to April 2022. Data were extracted from the relevant studies and analyzed with RevMan software. In a random effects model, standard mean difference (SMD) and risk ratio (RR) values were given with 95% confidence intervals. In total, pooled analysis included 7148 patients in 43 studies. The combined effect estimate showed significant differences between the ESWL success and ESWL failure groups in terms of Hounsfield unit (HU), Hounsfield density (HD), skin to stone distance (SSD), ureteral wall thickness (UWT), stone volume, stone area, abdominal fat parameters, diameter of proximal ureter, and hydronephrosis. However, perinephric stranding and renal cortical thickness were not found to be statistically significant between the study groups. HU, HD, SSD, UWT, stone volume, stone area, abdominal fat parameters, diameter of proximal ureter and hydronephrosis are effective factors for prediction of ESWL success. It is important to decide on treatment before the procedure for stones with appropriate diameter for ESWL.

Development and validation of a predictive model for treatment outcome after emergency extracorporeal shockwave lithotripsy in patients with symptomatic ureteral stones during the COVID-19 pandemic: in a large prospective cohort.

The predictors of treatment outcome after emergency extracorporeal shockwave lithotripsy (SWL) are not well characterized. Therefore, based on a large prospective cohort, we aimed to develop and validate a nomogram for predicting treatment outcome after emergency SWL in patients with symptomatic ureteral stones. The development cohort included 358 patients with symptomatic ureteral stones who underwent emergency SWL between June 2020 and August 2021 in our hospital. One hundred and twenty-nine patients with symptomatic ureteral stones participated in the validation cohort from September 2021 to April 2022. The data were prospectively recorded. The backward stepwise selection was applied using the likelihood ratio test with Akaike's information criterion as the stopping rule. The efficacy of this predictive model was assessed concerning its clinical usefulness, calibration, and discrimination. Finally, 15.6% (56/358) of patients in the development cohort and 14.0% (18/129) of those in the validation cohort suffered from stone-free failure after emergency SWL. We identified four predictors for stone-free failure: stone size, stone density, skin to stone distance (SSD), and degree of hydronephrosis. This model showed good discrimination with an area under the receiver operating characteristic (AUROC) curves of 0.935 (0.899-0.971) and good calibration (P = 0.059). The decision curve analysis showed that the model was clinically valuable. In this large prospective cohort, we found that stone size, stone density, SSD, and degree of hydronephrosis were predictors of treatment outcome after emergency SWL. This nomogram will be helpful in preoperative risk stratification to provide individualized treatment recommendations for each patient. Furthermore, early identification and appropriate management of patients may increase the success rate of emergency SWL during the COVID-19 pandemic.

571 Evaluating the Effectiveness of Extracorporeal Shockwave Lithotripsy (ESWL) for Ureteric Stones During COVID-19 Pandemic - A Single Centre Experience

AimReliance on ESWL for treating ureteric stone has increased during the COVID-19 pandemic. We examined the outcomes for ureteric stones treated with our on-site lithotripter to assess the success rate and determine the variables that could affect the outcome results.MethodA retrospective review using electronic records and images of patients who underwent ESWL for ureteric stones (January to December 2020). Univariate and multivariate analysis used to determine stone-free rate predictors (Stone Free rate/SFR: No residual stones on post-ESWL imagining).ResultsA total of 36 patients underwent ESWL for ureteric stones. Mean age was 58 years (21–90), and mean stone size was 8 mm (5–20). Stones were located in the proximal (67%) or lower ureter (33%). Overall SFR was 64% (67% proximal, 33% distal). 64% of patients required only one session to be stone free, with 60% stone free after two sessions. Stones <10mm had a SFR of 67%, compared to 58% for stone >10 mm. The only statistically significant predictor was stone size (longest dimension, p=0.04). No statistical significance with stone location (P=0.09), skin-to-stone distance (SSD) (P=0.7), stone density (P=0.3) or stone volume (P=0.3). In treatment failure, time to definitive ureteroscopy was 4 weeks.ConclusionOur overall SFR was slightly lower than expected but comparable to available literature. This data highlights the importance of patient selection for ESWL and would be useful in counselling about local success rate. More than half of the patients required only one session for stone clearance and stone size was the only significant predictor for successful ESWL.

Efficacy of electromagnetic extracorporeal shockwave lithotripsy on high-density ureteral stones.

Our aim was to evaluate electromagnetic extracorporeal shockwave lithotripsy (SWL) in treating high-density radiopaque ureteral stones on non-contrast computed tomography (NCCT). Adult patients with radiopaque stones in the ureter who underwent SWL in a high volume center between 2016 and 2017 were retrospectively included. NCCT characteristics such as mean stone density (MSD), stone size, skin to stone distance (SSD) were recorded before treatment. Treatment success was defined as complete stone clearance (SF). 108 patients were included. Global stones MSD was 1119 HU. 55% and 62% of patients were SF respectively after 1 and 2 sessions of SWL. There was no difference of success rates between the treatment of low MSD (<1000HU, n=33) and high MSD (≥1000HU, n=75) (P=0.57, OR=0.79, 95% CI [0.35-1.80]). The SF rate dropped to 31.6% for 19 patients with ureteral stenting before treatment (P=0.02, OR=3.34, 95% CI [1.16-9.62]). Mean stone size was 7.2mm, SF rate for stones over 7mm were statistically lower (P=0.04, OR=2.18, 95% CI [1.00-4.73]). 4 patients needed ureteral stenting in emergency after SWL (3.7%). Electromagnetic SWL is a safe and effective way to treat ureteral stones. A high-density stone on NCCT may not be detrimental. Many parameters should be involved in the treatment decision such as stone size and ureteral stenting. 4.

Efficacy of extracorporeal shockwave lithotripsy, with modified position of the machine head in the treatment of lower calyceal stones in obese patients.

Context:Extracorporeal shock wave lithotripsy (ESWL) has inferior results in the lower calyceal stones, especially in obese patients.Aims:This study aimed at evaluating of the efficacy of extracorporeal shockwave lithotripsy, with modified position of the machine head in the treatment of single lower calyceal stones in obese patients.Settings and Design:This was a prospective study (phase IV trial).Subjects and Methods:We studied the anterior rotation of the shock wave machine head in obese patients for the treatment of lower calyx stones. From February 2015 to June 2019, 105 obese patients (body mass index [BMI] ≥35) having lower calyx stones (≤20 mm) underwent ESWL at our institute. The procedure was done in a supine position, and the head of the shock-wave machine was tilted anteriorly. ESWL was considered successful if the kidney was completely cleared of stones.Statistical Analysis Used:The statistical methods used were descriptive statistics, mean, standard deviation frequency analysis, Chi-square test, unpaired t-test test, and Pearson correlations (r).Results:The mean BMI of these patients was 39.71 ± 2.8 kg/m2, the mean stone size was 17.4 ± 2.1 mm, the mean stone density was 767.1 ± 193.4 Hounsfield unit, and the mean of skin to stone distance (SSD) was 145.4 ± 4.5 mm. ESWL was successful in 86 (81.9%) patients; 13 patients (12.4%) showed complete success after the first session, while 37 (35.2%), 25 (23.8%), and 11 (10.5%) patients showed success after the second, third, and fourth sessions, respectively. ESWL failed in 19 (19.1%) cases. The success rate decreased significantly with higher stone density and SSD (P < 0.001), with negative correlations (r values) of −0.871 and −0.811, respectively.Conclusions:Anterior rotation of the head of the shock wave machine is a suitable option for the treatment of lower calyceal stones in obese patients.

A prospective observational study on the predictability of Triple-D score versus Quadruple-D score in the success rate of extracorporeal shock wave lithotripsy of renal stones 1-2 cm in diameter.

Introduction:The aim of the study is to evaluate the clinical efficacy of Triple-D scoring system versus Quadruple-D scoring system for assessing stone-free rate (SFR) in individuals with renal stones measuring 1–2 cm in diameter after extracorporeal shock wave lithotripsy (ESWL).Materials and Methods:The study was conducted on 120 patients who presented to a tertiary care center in eastern India. Systemic random sampling technique was applied with a sampling interval of 2. Triple-D scoring system comprising of three computed tomography based metrics – stone dimension (volume), stone density (Hounsfield unit), and skin-to-stone distance (SSD) was done before ESWL. Stone location was included as an additional parameter to formulate Quadruple-D scoring system where an extra score was given for stones in the non-lower polar region. Stone-free status was assessed by plain abdominal radiography 3 weeks after ESWL.Results:In the study population, stone dimension, stone density, and stone location were positive predictors of SFR after ESWL whereas age, sex, and body mass index of the patients, laterality of the stone and SSD were not. The area under the curve of Triple-D and Quadruple-D scoring systems were 0.598 and 0.674.Conclusion:Triple-D scoring system has been successfully validated as the SFR showed a parallel increase with every positive component. The Quadruple-D scoring system with a simple addition of stone location can further facilitate the validation of Triple-D scoring by increasing SFR, keeping the calculation simple and easy to use. These findings support the incorporation of Quadruple-D scoring system over Triple-D scoring system.

Success of extracorporeal shock wave lithotripsy based on CT texture analysis.

The aims of the study were to evaluate whether computerised tomography texture analysis (CTTA) based on non-contrast computed tomography (NCCT) has predictive value for the success of extracorporeal-shockwave lithotripsy (ESWL) in upper urinary tract stones (UUTS). This study included 156 of 356 patients undergoing ESWL for UUTS sized 0.5-2cm from 2015 to 2019. Patients with congenital kidney anomalies, radiolucent stones, multiple stones, treated for upper urinary tract stones previously and lower pole stones were excluded from study. The number of ESWL sessions of the patients was as follows: 78 (50%) patients had 1 session, 30 (19.2%) patients had 2 sessions and 48 (30.8%) patients had >2 sessions. First- and second-order CTTA properties of patients' UUTS were evaluated using texture analysis software (LIFEx Software). Other clinical features such as Hounsfield Unit (HU), initial stone size, body-mass index (BMI) and skin to stone distance (SSD) was recorded. The patients were divided into two groups according to ESWL success. Cases with residual stones larger than 4mm were considered failed cases. BMI, the standard deviation of HU, SSD, skewness, kurtosis, entropy and all second-order statistics were found to be statistically different between the two groups except for correlation (P<.05). Multivariate analysis showed longer SSD and four new parameters of CTTA (kurtosis, entropy, dissimilarity and energy by the distribution of pixel grey levels in the UUTS) to be significant predictors for unsuccessful ESWL outcomes. SSD and second-order CTTA properties (dissimilarity and energy) had an area under ROC curve of 0.802, 0.850 and 0.824 at a 95% confidence interval. ESWL success rate in all patients was 76.9%. CTTA can help select patients who will undergo ESWL for upper urinary tract stones. Thus, we can reduce treatment costs and ESWL complications by preventing unnecessary ESWL applications.

Can we successfully predict the outcome for extracorporeal shock wave lithotripsy (ESWL) for medium size renal stones? A single-center experience.

Extracorporeal shock wave lithotripsy (ESWL) is one of the most used modalities in treatment of renal stones, but its effectiveness can be influenced by many factors related to the patient or the stone itself which may affect the success of stone disintegration. The aim of our study was to investigate the predictive value of some patient and stone-related factors for ESWL success for renal stones. A total of 100 patients with single radiopaque renal stone 10-20 mm in diameter, undergoing ESWL were enrolled in this study. All patients had non contrast computed tomography (NCCT) done before ESWL. We evaluated body mass index (BMI), skin-to-stone distance (SSD), stone size and Hounsfield density comparing these values between stone free (SF) and residual stone (RS) groups. Of the 100 patients, 70% had successful disintegration. There was no significant difference between stone free (SF) and residual stone (RS) groups as regard age or BMI. Meanwhile, there was a significant difference between SF and RS groups as regard stones' density and SSD, with higher values in RS group but there was statistically insignificant difference as regard stone size (p = 0.522). Using logistic regression analysis, we found that Hounsfield unit (HU) was better in predicting successful disintegration than SSD but without statistical significance. HU and SSD are the independent predictive factors for ESWL outcome, and they should be considered when planning ESWL in treatment of medium size renal stones.

An observational study on the predictability of the Triple-D score in the success rate of extracorporeal shock wave lithotripsy in renal stones 1 – 2 cm in diameter

Introduction: Evaluation of Triple-D scoring system to assess the stone free rate in individuals who were given extracorporeal shock wave lithotripsy (ESWL) for renal stones measuring 10-20 mm in diameter. Materials and methods: The study subjects were 120 patients who presented to the urological outpatient department with complaints of renal stones. Systemic Random Sampling technique was applied to select study subjects for study population with a Sampling Interval of 2. Prior to ESWL, Triple-D scoring comprising of three CT based metrics - stone dimension (volume), stone density (HU) and skin-to-stone distance (SSD) was done prior to ESWL as described by Tran et al. The score ranged from 0 (worst) to 3 (best). Treatment efficacy was studied by plain abdominal radiography three weeks after ESWL. Complete clearance was considered the “stone free status”. Results: In the study population, stone dimension, stone density and stone location were positive predictors of stone free rate after ESWL whereas age, sex and BMI of the patients, laterality of the stone and skin to stone distance were not. The area under the curve (AUC) of Triple-D scoring system was 0.598.Conclusion: Triple-D scoring system has been successfully validated as the SFR showed a parallel increase with every positive component. &nbsp

A Prospective Longitudinal Study onthe Predictability of Quadruple-D Score in the Success Rate of Extracorporeal Shock Wave Lithotripsy for Renal Stones 1-2cm in Diameter

Introduction: Quadruple-D, based on Computed Tomography (CT) derived metrics, is a scoring system that helps urologists to predict the Stone Free Rate (SFR) following Extracorporeal Shock Wave Lithotripsy (ESWL) in renal stones. Aim: To evaluate the efficacy of Quadruple-D scoring system to assess the SFR in individuals with renal stones measuring 1-2 cm in diameter after giving ESWL. Materials and Methods: The study was conducted on 120 patients. Systemic random sampling technique was applied with a sampling interval of two. Quadruple-D scoring, comprising of four Computed Tomography (CT) based metrics that is stonedimension, stone density, Hounsfield units (HU), Skin-to-Stone Distance (SSD) and stone location, was done prior to ESWL. The scores ranged from zero (worst) to four (best) points. Plain abdominal radiography was done three weeks after ESWL to assess SFR. Complete clearance was considered the stone free status. Patients were divided into group A with complete stone clearance and group B with residual stone. All the statistical analysis was done using IBM SPSS 26.0. Student’s t-test or Mann-Whitney U-test was used to compare continuous variables. Fisher’s-exact test and Chi-square test were used to analyse the cross charts between two categories. Results:The mean ellipsoid Stone Volume (SV) was 396.44±163.23 mm3 and 395.81±227.52 mm3 in group A and B, respectively. The stone density was 724.28±210.90 in group A and 814.56±190.63 in group B. In group A, 9.20% and in group B, 34.09% of the patients had stones in lower calyx. The difference between the groups based on the above parameters were statistically significant. The Quadruple-D score was 2.09±0.65 and 1.54±0.79 in group A and B, respectively. The Area Under the Curve (AUC) of Quadruple-D scoring system was 0.674. The age, sex, BMI, laterality of the stone and SSD did not predict stone-free status in this study. Conclusion: Quadruple-D scoring system has been successfully validated as the SFR showed a parallel increase with every positive component. Quadruple-D is an easy to use clinical tool to predict the success rate of ESWL.

New computed tomographic predictors of complicated perioperative course of 17.5F mini-percutaneous nephrolithotomy (mini-PNL)

PurposeRadiological parameters predicting a postoperative stone-free status (SFS) or a complicated perioperative course of mini-PNL, are scarce. Our aim was to identify such factors for prone 17.5F mini-PNL.MethodsA monocentric cohort of 103 cases was retrospectively analysed for factors predicting SFS and relevant complications, i.e. Clavien–Dindo (CD) ≥ 2. Parameters measured on preoperative supine CT included maximal stone diameter, skin-to-stone distance (SSD), ideal tract length (ITL), access angle, minimal T12—Lower Kidney Pole distance (T12LP) and minimal Iliac Crest—Lower Kidney Pole distance (ICLP). Infundibulopelvic angle (IPA) was measured on intraoperative pyelography.ResultsThe median maximal stone diameter was lower in cases with postoperative SFS [16 mm (Min. 10; Max. 35) vs. 20 mm (Min. 6; Max. 85), p = 0.0052]. CD ≥ 2 was more frequent in cases with a bigger stone burden [19 mm (Min. 13; Max. 85) vs. 16 mm (Min. 6; Max. 49), p = 0.0056] and with the ribs in the access angle [7/23 (30.43%) vs. 8/76 (10.53%); p = 0.0454]. T12LP significantly differed in cases with and without CD ≥ 2 [80.48 mm (± 21.31) vs. 90.43 mm (± 19.42), p = 0.0397]; however, it had no influence on SFS (p > 0.05). SSD, ITL, IPA and ICLP were significant regarding neither SFS nor CD ≥ 2 prevalence (p > 0.05). Using multivariate logistic regression, T12LP was confirmed as an independent predictor on CD ≥ 2 prevalence.ConclusionsPreoperative computed tomographic factors indicating elevated kidney position influence perioperative course of mini-PNL. T12LP and the presence of ribs in the access angle are, apart from stone diameter, the most useful indicators for cases at risk of CD ≥ 2.

Outcome groups and a practical tool to predict success of shock wave lithotripsy in daily clinical routine.

To improve outcome prediction of extracorporeal shock wave lithotripsy (SWL) by development of a model based on easily available clinical and radiographical predictors and suitable for daily clinical use. We evaluated predictive factors for SWL success in 517 consecutive patients suffering from urinary calculi who underwent SWL between 2010 and 2018. Analyses included descriptive statistics, receiver operating characteristic statistics and logistic regression. Predictive value was improved by combining parameters using model selection and recursive partitioning. Of the 517 patients, 310 (60.0%) had a successful SWL. Best individual predictor of SWL success was mean attenuation (MAV), with an area under the curve (AUC) of 0.668, and an optimal cutpoint (OC) of 987.5 HU. The best multivariable model, including MAV, stone size, skin to stone distance (SSD), presence of an indwelling stent, and four interaction effects, yielded an AUC of 0.736. Recursive partitioning would categorize patients into three outcome groups with high (76.9%), intermediate (41%) and low (10%) success probability. High probability of SWL success (76.9%) was found for patients with a stone with MAV ≤ 987 HU or with MAV > 987 HU but stone size ≤ 11mm and SSD (45°) ≤ 88mm. A model based on four established predictors, and provided as an Excel®-Tool, can clearly improve prediction of SWL success. In addition, patients can be classified into three defined outcome groups based on simple cutpoint combinations. Both tools improve informed decision-making in daily clinical practice and might reduce failure rates.

Shockwave Lithotripsy Is an Efficacious Treatment Modality for Obese Patients with Upper Ureteral Calculi: Logistic Regression and Matched-Pair Analyses from a Dedicated Center Comparing Treatment Outcomes by Skin-to-Stone Distance.

Objectives: To assess the association of skin-to-stone distance (SSD) and stone-free rates following extracorporeal shockwave lithotripsy (SWL) using two statistical methods: logistic regression and a matched-pair analysis approach. Patients and Methods: Patients with a solitary radio-opaque upper ureteral calculus diagnosed on noncontrast computed tomography were included. Patients were treated with a Sonolith I-Sys Lithotripter (focal depth 17 cm). Stone treatment success was defined as stone free (fragments ≤3 mm) at 3 months. Failure was defined as persistent fragments beyond 3 months or requirement for intervention with ureteroscopy. The outcome was assessed by a plain kidney, ureter, and bladder radiograph (KUB) at 2 weeks. Logistic regression was used to determine association of patient and stone factors with treatment failure. The patient cohort was divided into tertiles by SSD, and matched-pair analysis was undertaken between individuals from the top and bottom tertiles (SSD ≤12 cm and SSD ≥14 cm). Matching criteria consisted of age, sex, maximum stone diameter (±2 mm), and stone density (±250 HU). Results: From a database of 2849 patients who underwent SWL, 397 patients were identified who had treatment of a single upper ureteral stone. Age (odds ratio [OR]: 1.03, 95% confidence interval [CI]: 1.01-1.04, p = 0.007), SSD (OR: 1.16, 95% CI: 1.03-1.32, p = 0.02), stone side (OR: 1.65, 95% CI 1.01-2.73, p = 0.05), stone diameter (OR: 1.09, 95% CI: 1.00-1.19, p = 0.05), and multiple sessions (OR: 4.65, 95% CI: 2.61-8.29, p < 0.001) were significantly associated with treatment failure by logistic regression univariable analysis. Multiple sessions was the only factor significantly associated with treatment failure on multivariable analysis (OR: 4.03, 95% CI: 2.18-7.42, p < 0.001). From a cohort of 141 patients with SSD ≥14 cm and 174 patients with a SSD ≤12 cm, 66 matches were identified (132 patients). Forty-nine patients (74.2%) with SSD ≥14 cm were deemed stone free at follow-up vs 51 patients (77.3%) with SSD ≤12 cm (p = 0.85). Conclusion: This study demonstrates by two statistical methods that SWL can provide efficacious treatment of upper ureteral stones in obese patients and that the upper threshold of SSD for SWL with Sonolith I-SYS could be revised to allow these patients the benefits of SWL.