Advancements in stone classification: unveiling the beauty of urolithiasis.

PURPOSE: Urolithiasis has become increasingly prevalent, leading to higher disability-adjusted life years and deaths. Various stone classification systems have been developed to enhance the understanding of lithogenesis, aid urologists in treatment decisions, and predict recurrence risk. The aim of this manuscript is to provide an overview of different stone classification criteria. METHODS: Two authors conducted a review of literature on studies relating to the classification of urolithiasis. A narrative synthesis for analysis of the studies was used. RESULTS: Stones can be categorized based on anatomical position, size, medical imaging features, risk of recurrence, etiology, composition, and morphoconstitutional analysis. The first three mentioned offer a straightforward approach to stone classification, directly influencing treatment recommendations. With the routine use of CT imaging before treatment, precise details like anatomical location, stone dimensions, and Hounsfield Units can be easily determined, aiding treatment planning. In contrast, classifying stones based on risk of recurrence and etiology is more complex due to dependencies on multiple variables, including stone composition and morphology. A classification system based on morphoconstitutional analysis, which combines morphological stone appearance and chemical composition, has demonstrated its value. It allows for the rapid identification of crystalline phase principles, the detection of crystalline conversion processes, the determination of etiopathogenesis, the recognition of lithogenic processes, the assessment of crystal formation speed, related recurrence rates, and guidance for selecting appropriate treatment modalities. CONCLUSIONS: Recognizing that no single classification system can comprehensively cover all aspects, the integration of all classification approaches is essential for tailoring urolithiasis patient-specific management.

Extracorporeal shock wave lithotripsy versus laser lithotripsy in the treatment of post-SWL steinstrasse: a randomized comparative study.

OBJECTIVE: To compare the efficacy of Holmium laser lithotripsy with that of extracorporeal shock lithotripsy (SWL) for post-SWL ureteral steinstrasse. MATERIALS AND METHODS: From January 2022 to July 2023, 36 patients with post-SWL ureteral steinstrasse were randomly divided into laser lithotripsy and SWL groups. Patients with pain, moderate to marked hydronephrosis, large leading stone fragments, and showing no spontaneous resolution within 3-4 weeks after medical expulsive therapy were included. Patients with sepsis were excluded. The success rate was the primary outcome. We compared the perioperative data between the groups. RESULTS: The success rate was higher in the ureteroscopy group than in the SWL group (p = 0.034). SWL was a significantly longer operation, and the fluoroscopy time was significantly longer in the SWL group than in the URS group (p = 0.027). Auxiliary procedures were more frequently performed in the SWL group than in the URS group (p = 0.02). JJ stents were inserted in 100% of patients in the URS group. Three patients (16.7%) underwent conversion to laser ureteroscopy after the second SWL session failed. No significant difference in the incidence of postoperative complications was observed between the groups, but the incidence of postoperative LUT was high in the ureteroscopy group. The mean hospital stay was 30 h in the ureteroscopy group. SWL was performed without the need for hospital admission. CONCLUSION: Ureteroscopic laser lithotripsy for steinstrasse was safe and effective, with a higher success rate, shorter fluoroscopy time, and shorter recovery period than SWL.

Radiation exposure of urologists during endourological procedures: a systematic review.

INTRODUCTION: Ionizing radiation is used daily during endourological procedures. Despite the dangers of both deterministic and stochastic effects of radiation, there is a lack of knowledge and awareness among urologists. This study reviewed the literature to identify the radiation exposure (RE) of urologists during endourological procedures. METHODS: A literature search of the Medline, Web of Science, and Google Scholar databases was conducted to collect articles related to the radiation dose to urologists during endourological procedures. A total of 1966 articles were screened. 21 publications met the inclusion criteria using the PRIMA standards. RESULTS: Twenty-one studies were included, of which 14 were prospective. There was a large variation in the mean RE to the urologist between studies. PCNL had the highest RE to the urologist, especially in the prone position. RE to the eyes and hands was highest in prone PCNL, compared to supine PCNL. Wearing a thyroid shield and lead apron resulted in a reduction of RE ranging between 94.1 and 100%. Educational courses about the possible dangers of radiation decreased RE and increased awareness among endourologists. CONCLUSIONS: This is the first systematic review in the literature analyzing RE to urologists over a time period of more than four decades. Wearing protective garments such as lead glasses, a thyroid shield, and a lead apron are essential to protect the urologist from radiation. Educational courses on radiation should be encouraged to further reduce RE and increase awareness on the harmful effects of radiation, as the awareness of endourologists is currently very low.

Radiation exposure of patients during endourological procedures.

PURPOSE: Considering the existing gaps in the literature regarding patient radiation dose (RD) and its associated risks, a systematic review of the literature on RD was conducted, focusing on percutaneous nephrolithotomy (PCNL), extracorporeal shock wave lithotripsy (SWL), and ureteroscopy (URS). METHODS: Two authors conducted a literature search on PubMed, Web of Science, and Google Scholar to identify studies on RD during endourological procedures. Two thousand two hundred sixty-six articles were screened. Sixty-five publications met the inclusion criteria using the PRISMA standards. RESULTS: RD was generally highest for PCNL, reaching levels up to 33 mSv, 28,700 mGycm2, and 430.8 mGy. This was followed by SWL, with RD reaching up to 7.32 mSv, 13,082 mGycm2, and 142 mGy. URS demonstrated lower RD, reaching up to 6.07 mSv, 8920 mGycm2, and 46.99 mGy. Surgeon experience and case load were inversely associated with RD. Strategies such as optimizing fluoroscopy settings, implementing ultrasound (US), and following the ALARA (As Low As Reasonably Achievable) principle minimized RD. CONCLUSIONS: This is the first systematic review analyzing RD, which was generally highest during PCNL, followed by SWL and URS. There is no specific RD limit for these procedures. Implementation of strategies such as optimizing fluoroscopy settings, utilizing US, and adhering to the ALARA principle proved effective in reducing RD. However, further research is needed to explore the factors influencing RD, assess their impact on patient outcomes, and establish procedure-specific reference levels for RD.

Ureteral wall thickness as a predictor for non-invasive treatment success for steinstrasse. Can we save time?

PURPOSE: We aimed to define factors affecting the non-invasive overall treatment success (medical expulsive therapy (MET) ± shock wave lithotripsy (SWL)) for uncomplicated ureteral steinstrasse (SS) clearance. METHODS: We retrospectively evaluated consecutive patients who underwent SWL for renal stones between 2017 and 2021. Patients with uncomplicated SS were included. All patient's demographic and radiological data, e.g., age, gender, pre-SWL stenting, SS site, type, leading stone size in widest diameter (< 10 mm and ≥ 10 mm), ureteral wall thickness (UWT) in mm against the leading stone were collected. If SS was diagnosed, medical treatment was given for 4 weeks. In case of MET failure, either SWL for the leading stones + MET or direct URS was done. Non-invasive treatment success (SFR) was considered if complete clearance of SS occurred with no complications or the need for invasive intervention. RESULTS: A total of 145 patients were included with mean age of 45.9 ± 12.4 years. SFR in case of MET only occurred in 27.9%. Complications happened in 26 patients (17.9%). Non-invasive treatment SFR was achieved in 78 patients (53.8%) totally where SS type I, leading stone size ≤ 10 mm type and decreased UWT around the leading stone increased treatment success. CONCLUSION: Ureteral wall thickness is an important factor predicting SS management success. Besides the decreased UWT, non-invasive management should be offered for type I SS with leading stone ≤ 10 mm.

Crucial role of SWL1 in chloroplast biogenesis and development in Arabidopsis thaliana.

KEY MESSAGE: The disruption of the SWL1 gene leads to a significant down regulation of chloroplast and secondary metabolites gene expression in Arabidopsis thaliana. And finally results in a dysfunction of chloroplast and plant growth. Although the development of the chloroplast has been a consistent focus of research, the corresponding regulatory mechanisms remain unidentified. In this study, the CRISPR/Cas9 system was used to mutate the SWL1 gene, resulting in albino cotyledons and variegated true leaf phenotype. Confocal microscopy and western blot of chloroplast protein fractions revealed that SWL1 localized in the chloroplast stroma. Electron microscopy indicated chloroplasts in the cotyledons of swl1 lack well-defined grana and internal membrane structures, and similar structures have been detected in the albino region of variegated true leaves. Transcriptome analysis revealed that down regulation of chloroplast and nuclear gene expression related to chloroplast, including light harvesting complexes, porphyrin, chlorophyll metabolism and carbon metabolism in the swl1 compared to wild-type plant. In addition, proteomic analysis combined with western blot analysis, showed that a significant decrease in chloroplast proteins of swl1. Furthermore, the expression of genes associated with secondary metabolites and growth hormones was also reduced, which may be attributed to SWL1 associated with absorption and fixation of inorganic carbon during chloroplast development. Together, the above findings provide valuable information to elucidate the exact function of SWL1 in chloroplast biogenesis and development.

Does pre-stenting influence outcomes of shockwave lithotripsy? A systematic review and meta-analysis.

OBJECTIVE: To determine whether preoperative use of JJ stents in patients undergoing shockwave lithotripsy (SWL) impacts on stone clearance and the rate of postoperative complications. PATIENTS AND METHODS: We screened multiple databases from inception to January 2021, using the relevant search terms for SWL in patients with a preoperative stent. Inclusion criteria were randomised controlled trials of ≥20 patients aged >18 years who had had SWL with a JJ stent. This review has been registered in the International Prospective Register of Systematic Reviews (PROSPERO; registration number CRD42023443195). Statistical analysis was performed using 'meta' in R. RESULTS: There were seven eligible studies (403 patients receiving JJ stents and 394 controls). There was no significant difference in the stone-free rate (SFR) following SWL with a JJ stent compared to SWL alone. When considering the complication rates, there was a significantly reduced risk of steinstrasse in patients with a JJ stent. However, there was no significant difference in the risk of other complications including pain, fever, and haematuria, and no significant difference in the likelihood of requiring auxiliary procedures or re-treatment. CONCLUSIONS: There was a reduced risk of steinstrasse in patients undergoing SWL with a JJ stent compared to SWL alone. However, there was no significant difference in the risk of other postoperative complications. Use of a JJ stent had no effect on the efficacy of SWL, with no significant difference in the SFR.

Outcomes of alpha-blockers as medical expulsive therapy following shockwave lithotripsy: a systematic review and meta-analysis.

OBJECTIVES: To determine stone-free rate following shockwave lithotripsy (SWL) with/without alpha-blockers as well as complication rates (individual and classified using the Clavien-Dindo system). MATERIALS AND METHODS: We performed a systematic review of all randomized controlled trials that included more than 20 patients (age > 18 years) and examined the use of alpha-blockers after SWL. Meta-analysis was performed using 'metafor' in R. We report risk ratios (RRs) with 95% confidence intervals (95% CIs). The PROSPERO ID for the trial was: CRD42021248108. RESULTS: We assessed 158 full-text articles and included a total of 21 studies in our review. There were 1445 patients receiving alpha-blockers and 1478 control patients. Those receiving alpha-blockers were significantly more likely to be stone-free (RR 1.12, 95% CI 1.07-1.16; P < 0.001). This effect was robust to 'trim-and-fill' adjustment. In those taking alpha-blockers there was a significant reduction in Clavien III-V complications and, on trim-and-fill adjustment, a significant reduction in Clavien I-II complications. There were also significant reduction in rates of steinstrasse, pain and requirement for auxiliary procedures. There was no significant difference in retreatment rates. These effects were robust to trim-and-fill adjustment. CONCLUSIONS: There is a modest increase in stone-free rates in those receiving alpha-blockers following SWL, with a reciprocal modest risk reduction for steinstrasse, pain and auxiliary procedures. However, alpha-blockers do not reduce the risk of requiring retreatment.

High-frequency shock wave lithotripsy: stone comminution and evaluation of renal parenchyma injury in a porcine ex-vivo model.

BACKGROUND: The electrohydraulic high-frequency shock wave (Storz Medical, Taegerwilen, Switzerland) is a new way to create small fragments with frequencies up to 100 Hertz (Hz). This study evaluated the efficacy and safety of this method in a stone and porcine model. MATERIALS AND METHODS: BEGO stones were put in a condom in a specifically designed fixture treated with different modulations to see stone comminution. Standardized ex vivo porcine model with perfused kidneys with 26 upper and lower poles of 15 kidneys was treated with the following modulations: voltage 16-24 kV, capacitor 12 nF and frequency up to 100 Hz. 2000-20,000 shock waves were applied to each pole. The kidneys were perfused with barium sulfate solution (BaSO4) and x-ray was performed to quantify the lesions using pixel volumetry. RESULTS: There was no correlation between the number of shock waves and the powdering degree or the applied Energy and the grade of pulverization in the stone model. Regarding the perfused kidney model, the number of shock waves, applied voltage and frequency had no direct correlation with the occurrence of parenchymal lesions The detected lesions of the renal parenchyma were minimal, technical parameters had no significant impact and the lesions did not differ from the results of former experiments using 1-1.5 Hz in the same model. CONCLUSIONS: High-frequency shock wave lithotripsy can produce small stone fragments to pass in a very short time. The injury to the renal parenchyma is comparable to the results of the conventional SWL using 1-1.5 Hz.

Outcomes of Paediatric Cystine Stone Management: Results of a Systematic Review.

PURPOSE OF REVIEW: We wanted to analyse the outcomes of surgical (SWL, URS, PCNL) and medical management of cystine stones in the paediatric population in terms of stone-free status and complication rates, based on all the available literature evidence. RECENT FINDINGS: A systematic review of literature was performed for all studies with paediatric cystine stone management. Twelve studies met the eligibility criteria, of which 4 analysed outcomes of SWL, 2 of URS and 3 of PCNL and 3 focused on the effect of either alkalising agents (potassium citrate, citric acid) or cysteine-binding thiol (CBT) agents (tiopronin, penicillamine). The reported SFR in studies ranged from 50 to 83%, 59 to 100% and 63 to 80.6%, with a complication rate of 2.8-51%, 14-27% and 12.9-15.4% with SWL, URS and PCNL, respectively. Paediatric cystine stones treatment should aim at complete stone clearance, preservation of renal function and prevention of further recurrences. SWL achieves inferior results in case of cystine stones. URS and PCNL are safe and effective procedures in the paediatric population, with a low rate of major complications. Adherence to medical prevention therapies may prolong recurrence-free periods.

The New Lithotripsy Index predicts success of shock wave lithotripsy.

AIM: The aim of this study is to evaluate the factors affecting treatment success in patients who underwent Shock wave lithotripsy (SWL) and to investigate the effect of the Storz Medical Lithotripsy Index (SMLI) on treatment effectiveness. METHODS: Prospective data were collected on patients undergoing SWL treatment for kidney stones between January 2013 and May 2021. Stone location, number and size were determined with non-contrast CT (NCCT) for all patients. All patients underwent SWL with a Storz Modulith SLK lithotripsy machine without anaesthesia. The total amount of energy applied to the stone was calculated using the SMLI. All patients were evaluated for stone-free status by X-ray at least 2 weeks after treatment. The success of the procedure was defined as the patient being completely stone free or the detection of residual fragments < 4 mm that did not require further treatment. RESULTS: A total of 1230 patients with kidney stones were included in the study. The mean age of the patients was 42.33 ± 11.78 (18-75), and the mean BMI was 28.47 ± 8.78 (19.25-38.52). During SWL, 75.6% of patients demonstrated excellent pain tolerance (930/1230). A total of 116 patients could not tolerate the pain during SWL (9.4%). Treatment success was associated with fewer treatment sessions (2.34 ± 1.75 vs. 2.90 ± 2.04; p < 0.001), smaller stone size (7.52 ± 3.29 vs 8.60 ± 3.93; p < 0.001) and higher SMLI/stone size (25.11 ± 13.63 vs. 22.27 ± 14.50; p < 0.001). In the univariate and multivariate regression analysis, the factors affecting the success of the treatment were the number of sessions (OR 1.170), stone size (OR 1.142), number of shocks (OR 1.005), SMLI/stone size (OR 1.024) and pain tolerance (OR 0.692). CONCLUSION: In the treatment of kidney stones with SWL, stone site, stone size, SMLI/stone size, and pain tolerance are the factors affecting success. SMLI per stone size is a statistically significant factor for predicting SWL success.

Optimization of shockwave lithotripsy use for single medium sized hard renal stone with stone density ≥ 1000 HU. A prospective study.

PURPOSE: To identify shock wave lithotripsy (SWL) success predictors in hard renal stones (average stone density ≥ 1000 HU). MATERIALS: We prospectively evaluated patients who underwent SWL for hard renal stones between April 2018 and December 2020. Radiological parameters were identified, e.g., stone site, size, the average density in addition to stone core and shell mean density, and renal cortical thickness (RKT). SWL sessions were performed using Doli-S lithotripter till a maximum of 3-4 sessions with 2-4 weeks interval. Initial response to SWL included stone fragmentation and decreased stone size after the first SWL. Treatment success was considered if complete clearance of renal stones occurred or in case of clinically insignificant residual fragments ≤ 4 mm after 12 weeks follow up by NCCT. RESULTS: Out of 1878 patients who underwent SWL, the study included 157 patients with hard renal stones. Treatment overall success was found in 92 patients (58.6%) where 69 patients (43.9%) had complete stone clearance. On multivariate analysis, stone shell density < 901 HU, maximum stone size < 1 cm, RKT > 1.95 cm and initial treatment response were associated with increased the success rate after SWL for hard renal stones (P = 0.0001, 0.009, < 0.0001 and < 0.0001, respectively). CONCLUSION: In hard renal stones, treatment overall success was found in 58.6% where complete stone clearance was found in 43.9%. Stone outer shell fragility, lower stone size, increased RKT and initial response to SWL were associated with a higher success rate at 12-week follow-up.

Design, synthesis, and in vivo evaluation of GO-SWL-Ahx-K-SWL.

In order to acquire both expanded binding ability with the EphA2 receptor and superior drug delivery capacity, we designed and synthesized the modified GO-SWL-Ahx-K-SWL conjugate as a potential targeted therapeutic drug for non-small cell lung cancer (NSCLC). Various characterization methods have confirmed that the conjugate is consistent with the theoretical peptide. The cytotoxicity test results showed that the conjugate was slightly more toxic to A549 cells than in 3 T3 cells, and the toxicity increased in a concentration-dependent manner. Single photon emission computed tomography/computed tomography (SPECT/CT) fusion imaging was performed to evaluate the conjugate binding to EphA2 receptor in vivo. The images showed obvious radioactive concentration in tumor tissues and significantly higher ratios of the tumor and muscle in the 125I-GO-SWL-Ahx-K-SWL group (10.78) than in the 125I-SWL-Ahx-K-SWL group (5.21) at all three time points (P < 0.01).

No-show after extracorporeal shock wave lithotripsy treatment in endourology clinic: Can we build a typical patient profile?

OBJECTIVES: Patients "no-show" in outpatient clinics is a worldwide challenge. Healthcare providers and patients suffer from negative impacts that include increased expenditure, clinical management ineffectiveness, and decreased access to care. This study aims to evaluate no-show rate among extracorporeal shock wave lithotripsy patients visiting endourology clinic and to identify the demographic and clinical predictors of no-show. METHODS: A cross-sectional and historical cohort study using electronic medical records. We included 790 patients aged >18 years old referred for endourology clinic following shock wave lithotripsy during 2010-2017 at Hadassah Medical Center in Israel. We predicted no-show rate following shock wave lithotripsy by various patient characteristics by a multivariate logistic regression model. RESULTS: Overall, 291 (36.8%) patients did not arrive for postoperative clinic. Of these, 91 (11.52%) patients referred to Emergency Department. Patients who were younger in age (odds ratio 1.49, 95% confidence interval 1.08-2.04), patients who underwent hospitalization ≥3 days (odds ratio 1.63, 95% confidence interval 1.11-2.41) and patients who had undergone a stent-free shock wave lithotripsy (odds ratio 5.71, 95% confidence interval 2.40-13.57) were significantly associated with higher no-show rate. Larger stone size was associated with reduction in no-show rate with every millimeter increase of stone diameter was associated with a reduction of 6.1% probability for no-show (odds ratio 0.94, 95% confidence interval 0.89-0.99). CONCLUSIONS: Predicting patients' characteristics and no-show patterns is necessary to improve clinical management efficiency, access to care, and costs. We showed that patients who were younger, patients who underwent stent-free shock wave lithotripsy, patients who had a smaller stone, and patients who underwent a longer hospitalization were more prone to miss their appointment. Paying attention to the characteristics of individual patients may assist in implementing intervening program of patient scheduling.

Percutaneous nephrolithotomy versus extracorporeal shock wave lithotripsy for renal insufficiency.

OBJECTIVE: To assess the effect and outcome of percutaneous nephrolithotomy (PNL) versus extracorporeal shock wave lithotripsy (SWL) in patients with renal insufficiency. PATIENTS AND METHODS: A prospective randomized clinical study of 104 renal insufficiency patients with renal stones (serum creatinine 2-4 mg/dl and eGFR < 60 ml/min/1.73 m2 more than 3 months) randomized into two groups: Group A underwent PNL; Group B underwent shock wave lithotripsy (SWL). Treatment effects and outcomes compared between the two groups. RESULTS: Between Group A of 50 patients and Group B of 54 cases, demographic data showed no statistically significant differences. The stone-free rate was 84% in Group A versus 26.6% in Group B after the first SWL session. After completion of all SWL sessions, the rate was 88.9% for Group B. Comparing pre and postoperative results of Group A, there is significant improvement of serum creatinine concentrations by 9.1% (p = 0.001), significant improvement of creatinine clearance (p = 0.000) and eGFR (p = 0.003). Although regarding Group B preoperatively and 3 months after SWL there is significant improvement by 8.7% (p = 0.0001), which is less than that of Group A, there is also, improvement of eGFR by 6.7% (p = 0.001), which is less than the eGFR improvement in Group A (12.3%). But there is no statistically significant difference is noted for creatinine clearance in Group B (p = 0.09). CONCLUSION: The outcomes for PNL and SWL in patients with renal insufficiency and renal stones are encouraging as minimally invasive procedures with no negative effects on kidney function.

Value of early second session shock wave lithotripsy in treatment of upper ureteric stones compared to laser ureteroscopy.

PURPOSE: The safety and efficacy of early second session shock wave lithotripsy (SWL) compared with laser ureteroscopy (URS) for the treatment of upper ureteric stones were evaluated. METHODS: From January to October 2019, 108 patients with upper ureteric stones (< 1.5 cm and ≤ 1000 Hounsfield unit (HU)) were randomized into SWL and laser URS groups. The second SWL session was performed within 48-72 h of the first session. Using plain abdominal X-ray and ultrasonography, patients were evaluated 48-72 h after the first SWL session and one week after the second and third SWL sessions or one week after URS. The procedure was considered a success when no additional procedures were needed to clear the stone. To determine the stone-free rate (SFR), noncontrast computed tomography of the urinary tract was performed three months postoperatively. RESULTS: In the SWL group, the success rates were 92.6% and 94.4% after the second and third sessions. The SFR was 96.2% in the laser URS group. The success rates were not significantly different between the second and third SWL sessions versus the laser URS (p = 0.418 and 0.660, respectively). Operative and fluoroscopy times were significantly longer in the SWL group (p = 0.001), and JJ stent insertions were needed after laser URS. CONCLUSION: Ultraslow full-power SWL treatment of patients with upper ureteric stones (< 1.5 cm and ≤ 1000 HU) with an early second session is safe and effective compared to laser URS. Patients who do not respond to early second SWL session should be shifted to another treatment modality.

The alternating bidirectional versus the standard approach during shock wave lithotripsy for upper lumbar ureteric stones: a randomized controlled trial.

PURPOSE: To compare the outcome of shock wave lithotripsy (SWL) for upper lumbar ureteric stones using the alternating bidirectional approach versus the standard approach during the first session. METHODS: Our study was a randomized controlled trial including patients with single radio-opaque stone < 1 cm located in the upper lumbar ureter (from the ureteropelvic junction till the level medial to the lower margin of the kidney). SWL was conducted using electromagnetic Dornier Gemini Lithotripter. In group 1, patients were treated with the alternating under and over-table approach during the first session only and if other sessions were needed, the standard under-table approach was used. In group 2, patients were treated with the standard under-table approach during all sessions. Stone disintegration after the first session was assessed by kidney-ureter-bladder X-ray, renal ultrasonography and noncontrast computed tomography. Moreover, the incidence and severity of postoperative complications were evaluated. RESULTS: Forty-eight patients in each group completed the study. Patient demographics and stone characteristics were comparable in both groups. Complete disintegration was achieved in 41.7% of patients in group 1 versus 18.8% in group 2 (P = 0.021). Stone-free rate (SFR) was 58.3% and 20.8% in group 1 and 2 respectively (P = 0.001). The mean session time was 56.42 min in group 1 versus 46.35 min in group 2 (P < 0.001). There was no significant difference in postoperative complications. CONCLUSION: Stone disintegration and SFR after the first SWL session are higher when using the alternating bidirectional approach for upper lumbar ureteric stones at the expense of longer procedural duration. TRIAL REGISTRATION: ClinicalTrials identifier (ID: NCT03243682), clinicaltrials.gov.

Anterior or posterior SWL in proximal ureteral stones opposite to 4th and 5th lumbar vertebrae?

BACKGROUND: Results of SWL in treatment of upper ureteral calculi are conflicting which is definitely affected by stone locations along the proximal ureter, which is may be due to the more deep and medial course of the ureter distally over the thick and strong abdominal back wall which may hinder shock waves. METHODOLOGY: One hundred patients with radiopaque proximal ureteral stone opposite 4th and 5th lumbar vertebrae who had SWL were randomized into two groups. First group had SWL through anterior belly wall in supine position with countertraction, the second group had standard posterior SWL. Patient's demographics and stone characters were evaluated assessing stone burden and calculating S.T.O.N.E score. Patients were followed up to assess stone-free rate using serial digital plain X-ray KUB. RESULTS: Anterior approach needed less power to reach SFR (p = 0.05) in less number of sessions where 90% of cases in anterior group had only one session to reach SFR versus 52% in posterior group (p = 0.001). Also, post-SWL pain, hematuria, obstruction and infection were significantly less in anterior group (p = 0.005). Although patients who had anterior approach showed statistically significant shorter time to stone expulsion. SFR does not differed significantly between study groups (p = 0.02). On further analysis; anterior SWL had a better chance to reach SFR (HR = 1.6, p = 0.001). CONCLUSION: It seems that anterior SWL approach in supine position is safe and effective especially in mild obese patient with floppy abdomen. Patients who had anterior SWL approach had a better chance to achieve stone-free rate.

Deep Learning versus Spectral Techniques for Frequency Estimation of Single Tones: Reduced Complexity for Software-Defined Radio and IoT Sensor Communications.

Despite the increasing role of machine learning in various fields, very few works considered artificial intelligence for frequency estimation (FE). This work presents comprehensive analysis of a deep-learning (DL) approach for frequency estimation of single tones. A DL network with two layers having a few nodes can estimate frequency more accurately than well-known classical techniques can. While filling the gap in the existing literature, the study is comprehensive, analyzing errors under different signal-to-noise ratios (SNRs), numbers of nodes, and numbers of input samples under missing SNR information. DL-based FE is not significantly affected by SNR bias or number of nodes. A DL-based approach can properly work using a minimal number of input nodes N at which classical methods fail. DL could use as few as two layers while having two or three nodes for each, with the complexity of O{N} compared with discrete Fourier transform (DFT)-based FE with O{Nlog2 (N)} complexity. Furthermore, less N is required for DL. Therefore, DL can significantly reduce FE complexity, memory cost, and power consumption, which is attractive for resource-limited systems such as some Internet of Things (IoT) sensor applications. Reduced complexity also opens the door for hardware-efficient implementation using short-word-length (SWL) or time-efficient software-defined radio (SDR) communications.

The effect of focus size and intensity on stone fragmentation in SWL on a piezoelectric lithotripter.

PURPOSE: We aim to analyze the efficacy of different focus sizes and the influence of pulse pressure (intensity) during shock wave lithotripsy (SWL) in terms of stone fragmentation. METHODS: Combination of three focal sizes (F1 = 2 mm, F2 = 4 mm, F3 = 8 mm) and 11 output pressure settings (intensity 10-20) of a piezoelectric lithotripter (Wolf PiezoLith 3000) were tested on artificial stones (n = 99). The stones were placed within a 2 mm mesh cage. The needed number of shockwaves (SW) to first visible crack, 50% and 100% stone disintegration were recorded. RESULTS: Similar number of SW's were observed until the first crack 10, 11 and 11 SW's for F1, F2, and F3, respectively (p > 0,05). The median number of SW needed for 50% stone disintegration was 245 for F1 group, 242 for F2 group and 656 for F3 group. F1 vs F2 p = 0.7, F1 vs F3 and F2 vs F3 p < 0.05. Similarly, with larger focus size a higher number of shockwaves were necessary for 100% stone disintegration. 894, 877 and 1708 SW's for F1, F2 and F3, respectively. Only for F1 vs F3 and F2 vs F3 (all p < 0.05) a statistical difference was observed. These findings were consistent in all different power settings, with an increased difference in lower power levels (≤ 14). CONCLUSIONS: A smaller focus size, as well as a higher peak pressure results in a more effective stone fragmentation. However, these results need to be confirmed in an in vivo setting with multiple parameters interfering the efficacy, like BMI, respiration or stone migration.