Follow-up of urolithiasis patients after treatment: an algorithm from the EAU Urolithiasis Panel.

OBJECTIVE: To develop a follow-up algorithm for urinary stone patients after definitive treatment. MATERIALS AND METHODS: The panel performed a systematic review on follow-up of urinary stone patients after treatment (PROSPERO: CRD42020205739). Given the lack of comparative studies we critically evaluated the literature and reached a consensus on the follow-up scheme. RESULTS: A total of 76 studies were included in the analysis, including 17 RCTs. In the stone-free general population group, 71-100% of patients are stone-free at 12 months while 29-94% remain stone-free at 36 months. We propose counselling these patients on imaging versus discharge after the first year. The stone-free rate in high-risk patients not receiving targeted medical therapy is < 40% at 36 months, a fact that supports imaging, metabolic, and treatment monitoring follow-up once a year. Patients with residual fragments ≤ 4 mm have a spontaneous expulsion rate of 18-47% and a growth rate of 10-41% at 12 months, supporting annual imaging follow-up. Patients with residual fragments > 4 mm should be considered for surgical re-intervention based on the low spontaneous expulsion rate (13% at 1 year) and high risk of recurrence. Plain film KUB and/or kidney ultrasonography based on clinicians' preference and stone characteristics is the preferred imaging follow-up. Computed tomography should be considered if patient is symptomatic or intervention is planned. CONCLUSIONS: Based on evidence from the systematic review we propose, for the first time, a follow-up algorithm for patients after surgical stone treatment balancing the risks of stone recurrence against the burden of radiation from imaging studies.

Patient's preferences: an unmet need by current urolithiasis guidelines: a systematic review.

INTRODUCTION: Shared decision making (SDM) in surgical specialties was demonstrated to diminish decisional regret, decisional anxiety and decisional conflict. Urolithiasis guidelines do not explicit patient preference to choose treatment. The aim of this review article was to perform a systematic evaluation of published evidence regarding SDM in urinary stone treatment. METHODS: A systematic review in accordance PRISMA checklist was conducted using the MEDLINE (PubMed) database. Inclusion criteria were studies that evaluated stone treatment preferences. Reviews, editorials, case reports and video abstracts were excluded. ROBUST checklist was used to assess quality of the studies. RESULTS: 188 articles were obtained. After applying the predefined selection criteria, seven articles were included for final analysis. Six out of seven studies were questionnaires that propose clinical scenarios and treatment alternatives. The last study was a patient preference trial. A general trend among included studies showed a patient preference towards the least invasive option (SWL over URS). The main reasons to choose one treatment over the other were stone-free rates, risk of complications and invasiveness. DISCUSSION: This review provides an overview of the patients' preferences towards stone treatment in small- and medium-sized stones. There was a clear preference towards the least invasive management strategy. The main reason was less invasiveness. This is opposed to the global trends of performing more ureteroscopies and less SWL. Physicians played a pivotal role in counselling patients. SDM should be encouraged and improved. The main limitation of this study is the characteristics of the included studies.

2022 Recommendations of the AFU Lithiasis Committee: Endoscopic description of renal papillae and stones.

Endoscopic observation is performed during treatments by flexible ureteroscopy to differentiate in situ between renal papillary abnormalities and stones based on their concordance with Daudon's morphological/composition descriptions adapted to endoscopy. These intraoperative visual analyses are now an integral part of the urinary stone disease diagnostic approach in addition to the morphological/structural and spectrophotometric analysis that remains the reference exam, but that loses information on the stone component representativeness due to the development of in situ laser lithotripsy. These are the first practical recommendations on the endoscopic description of renal papillae and stones. METHODOLOGY: These recommendations were developed using two methods: the Clinical Practice Recommendations (CPR) and the ADAPTE method, depending on whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis [EAU Guidelines on urolithiasis. 2022]) and their adaptability to the French context.

2022 Recommendations of the AFU Lithiasis Committee: Management of symptomatic urinary stones.

The acute situation, caused by an obstructive stone, is defined by a renal colic that may be uncomplicated, complicated, or at risk in specific conditions. Its management may be medical or require interventional treatment by extracorporeal shockwave lithotripsy, endoscopic removal, or ureteroscopy. METHODOLOGY: These recommendations were developed using two methods, the Clinical Practice Recommendations (CPR) and the ADAPTE method, in function of whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis) [EAU Guidelines on urolithiasis. 2022] and whether they could be adapted to the French context.

2022 Recommendations of the AFU Lithiasis Committee: Extracorporeal shock wave lithotripsy (ESWL).

Extracorporeal shock wave lithotripsy (ESWL) is a minimally invasive technique for the fragmentation of urinary tract stones using shock waves under fluoroscopic and/or ultrasound guidance. ESWL results depend on the indication (stone size/composition, clinical context) and also on how it is performed. The stone structure, nature and density (Hounsfield units; evaluated by CT without contrast agent) influence the fragmentation achieved by ESWL. The upper size limit of kidney stones has been lowered to 15mm (1.68cm3) due to the increased risk of steinstrasse with larger sizes and the potential need of anesthesia and ureteral stenting. Conversely, the development of endourological technologies allows a finer stone fragmentation and/or better elimination, thus reducing the risk of steinstrasse and decreasing the potential number of sessions or additional interventions. METHODOLOGY: These recommendations were developed using two methods: the Clinical Practice Recommendations method (CPR) and the ADAPTE method, depending on whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis [EAU 2022]) and their adaptability to the French context.

[Diagnosis and treatment of four cases of asymptomatic and non-hydrous ureteral calculi].

This paper analyzed the clinical data, diagnosis and treatment of 4 asymptomatic patients with ureteral calculi without hydrops in our hospital from October 2018 to January 2019, and comprehensively discussed the previous literature. The 4 patients in this group had no obvious clinical symptoms, no positive stones were found in the B-ultrasound of the urinary system, and no hydroureter and hydroureter of the affected side was found. Urinary CT scan confirmed ureteral stones. They were all located in the lower ureter, and the stones obstructed the lumen. The stones were round and smooth, and there was no obvious hyperplasia and edema in the surrounding mucosa. The lithotripsy was completed in the first-stage operation, and the DJ catheter was left behind for one month after the operation. Based on the clinical diagnosis and treatment process of the 4 cases of asymptomatic calculi in this group and the analysis of previous studies, these patients were mostly detected by imaging examinations or other systematic imaging examinations during the regular review of urinary calculi. Ureteral stones with obstruction did not necessarily have stone-related symptoms. The onset of renal colic involved an increase in intraluminal pressure, related stimulation of nerve endings, smooth muscle spasms caused by stretching of the ureteral wall, and systemic changes in cytokines and related hormones. Cascade reactions, etc., were associated with the movement of stones down. Ureteral stones without hydrops were mostly located in the lower ureter, which had a certain buffering effect on obstructive pressure. Asymptomatic ureteral calculi could also induce irreversible damage to renal function, and the proportion of damage increased with the diameter of the stone. Patients with a history of urinary calculi, especially those with asymptomatic stones for the first time, should be paid attention to during clinical follow-up. At present, there are few research reports on asymptomatic and non-accumulating ureteral calculi. We analyze the clinical diagnosis and treatment process and characteristics of this group of patients combined with previous literature to provide a reference for the diagnosis and treatment of such patients.

Pulsed Thulium:YAG laser - What is the lithotripsy ablation efficiency for stone dust from human urinary stones? Results from an in vitro PEARLS study.

BACKGROUND: The novel pulsed thulium:yttrium-aluminum-garnet (p-Tm:YAG) laser was recently introduced. Current studies present promising p-Tm:YAG ablation efficiency, although all are based on non-human stone models or with unknown stone composition. The present study aimed to evaluate p-Tm:YAG ablation efficiency for stone dust from human urinary stones of known compositions. METHODS: Calcium oxalate monohydrate (COM) and uric acid (UA) stones were subjected to lithotripsy in vitro using a p-Tm:YAG laser generator (Thulio®, Dornier MedTech GmbH, Germany). 200 J was applied at 0.1 J × 100 Hz, 0.4 J × 25 Hz or 2.0 J × 5 Hz (average 10W). Ablated stone dust mass was calculated from weight difference between pre-lithotripsy stone and post-lithotripsy fragments > 250 µm. Estimated ablated volume was calculated using prior known stone densities (COM: 2.04 mg/mm3, UA: 1.55 mg/mm3). RESULTS: Mean ablation mass efficiency was 0.04, 0.06, 0.07 mg/J (COM) and 0.04, 0.05, 0.06 mg/J (UA) for each laser setting, respectively. This translated to 0.021, 0.029, 0.034 mm3/J (COM) and 0.026, 0.030, 0.039 mm3/J (UA). Mean energy consumption was 26, 18, 17 J/mg (COM) and 32, 23, 17 J/mg (UA). This translated to 53, 37, 34 J/mm3 (COM) and 50, 36, 26 J/mm3 (UA). There were no statistically significant differences for laser settings or stone types (all p > 0.05). CONCLUSION: To our knowledge, this is the first study showing ablation efficiency of the p-Tm:YAG laser for stone dust from human urinary stones of known compositions. The p-Tm:YAG seems to ablate COM and UA equally well, with no statistically significant differences between differing laser settings.

Correlation of the Degree of Hydronephrosis and Computed Tomography Value of Calculi with Efficacy of Ureteroscopic Lithotripsy in Patients with Upper Urinary Tract Infectious Calculi.

OBJECTIVE: The correlation of the degree of hydronephrosis and computed tomography (CT) value of calculi with the efficacy of ureteroscopic lithotripsy (URSL) in patients with upper urinary tract infectious calculi was explored. METHODS: The clinical data of 152 patients with upper urinary tract infectious calculi and on URSL in Shanghai Baoshan District Wusong Central Hospital from November 2019 to November 2021 were collected for retrospective analysis. All patients received CT examination before surgery. According to the therapeutic effect of URSL, all patients were divided into the non-calculi group (NCG, n = 101) and residual calculi group (RCG, n = 51), which were compared in terms of the degree of hydronephrosis and CT value of calculi. Then, the correlation of the degree of hydronephrosis and CT value of calculi with the efficacy of URSL in patients was analysed. RESULTS: No significant difference in clinical data was found between the groups (p > 0.05). Patients in the NCG group had lower degree of hydronephrosis than those in the RCG group (p < 0.05), and the NCG had lower CT value of calculi (p < 0.001). Spearman rank correlation analysis showed that the degree of hydronephrosis in patients with upper urinary tract infectious calculi was negatively correlated with the efficacy of URSL (r = -0.676, p < 0.001), and the CT value of calculi in such patients was negatively correlated with the efficacy of URSL (r = -0.795, p < 0.001). CONCLUSIONS: The degree of hydronephrosis and CT value of calculi were negatively correlated with the efficacy of URSL. Both can be used to predict clinical efficacy and have clinical guiding value for the formulation of treatment plans in patients with urinary tract infectious calculi.

A population-based retrospective cohort study of surgical trends and outcomes of pediatric urolithiasis in Ontario, Canada (2002-2019).

INTRODUCTION: The worldwide incidence of pediatric urinary stone disease (PUSD) is increasing. However, there is no commensurate data on whether this translates to an increasing need for surgical intervention for PUSD, given the role of conservative management. OBJECTIVE: We aimed to evaluate the trends and outcomes of clinically significant PUSD, using administrative databases to identify patients surgically treated for PUSD. STUDY DESIGN: This retrospective population-based cohort study assessed the incidence and trends of surgically treated PUSD and outcomes in Ontario, Canada in patients <18 years of age who underwent their first PUSD procedure between 2002 and 2019 utilizing administrative databases held at the Institute of Clinical Evaluative Sciences (ICES). We assessed the incidence of surgically treated PUSD, demographics, initial surgical treatment and imaging modality, and risk factors for repeat intervention within 5 years. Statistical analyses summarized demographics, surgical trends, and logistic regression was used to identify risk factors for repeat surgical intervention. RESULTS: We identified 1149 patients (mean age 11.3 years), with 59.6% older than 12 years. There was a decrease in the number of PUSD procedures performed per year that was close to statistical significance (p = 0.059) and a trend towards increased utilization of ureteroscopy (URS) compared with Shockwave Lithotripsy (SWL). In addition, there was a significant increase in the proportion of females surgically treated with PUSD (p = 0.001). In the 706 patients followed for 5 years, 17.7% underwent a repeat procedure within 6 months, while 20.4% underwent a repeat procedure from 6-months to 5 years. Renal stone location (OR 2.79, 95% confidence interval (CI) 1.62-4.80, p = 0.0002) and index SWL (OR 1.66, 95% CI 1.20-2.31, p = 0.0025) were risk factors for repeat surgical intervention within the first 6-months. There was an increasing utilization of ultrasound (US) compared to computerized tomography (CT) (p = 0.0008). DISCUSSION: Despite the literature reporting increasing PUSD incidence, we observed a non-significant decrease in the number of surgical PUSD procedures performed. Exclusion of those treated conservatively may explain our results. The increase in the proportion of females treated reflects the narrowing gender gap in stone disease. A trend towards increased URS utilization was observed and re-intervention rates were similar to previous studies. CONCLUSION: The overall rate of surgically treated PUSD did not show an increasing trend in Ontario, Canada from 2002 to 2019. URS was the most common surgical treatment modality, with a corresponding decline in SWL rates. PUSD was associated with a high surgical re-intervention rate within 6 months.

[Efficacy and safety of superpulse thulium laser lithotripsy in the intracavitary treatment of urinary calculi].

Objective: To evaluate the efficacy and safety of superpulse thulium laser lithotripsy in the intracavitary treatment of urinary calculi. Methods: From May 2021 to July 2022, patients diagnosed with urinary calculi were screened in four medical centers. Those who met the criteria were treated with superpulse thulium fiber laser under endoscope. The patients' perioperative conditions were recorded. The main effective index was stone-free rate (SFR) 4 weeks after operation, the main safety index was the failure rate of the experimental instruments during operation, and the secondary safety index was the incidence rate of perioperative complications. Results: A total of 76 eligible patients completed superpulse thulium fiber laser lithotripsy, with an average age of (52.0±11.1) years, 54 males and 22 females. There were 31 renal stones, 43 ureteral stones and 2 bladder stones. Percutaneous nephrolithotomy was performed in 17 patients. Ureteroscopy lithotripsy/flexible ureteroscopy lithotripsy was performed in 57 patients and transurethral bladder lithotripsy was in 2 patients. The lithotripsy time of all patients was (50.9±31.4) minutes. There was no failure of experimental instruments during the operation. Six patients refused follow-up examination after operation. The incidence of postoperative adverse events was 61.8% (47/76). One patient needed hospitalization due to inguinal hernia after operation, and the rest were classified as Clavien-dindo grade 1-2. The SFR was 94.3% (66/70) at 4 weeks after operation. Conclusion: It is effective and safe to use superpulse thulium fiber laser in the treatment of urinary calculi.

Pulsed thulium:YAG laser-ready to dust all urinary stone composition types? Results from a PEARLS analysis.

PURPOSE: To evaluate whether stone dust can be obtained from all prevailing stone composition types using the novel pulsed thulium:YAG (p-Tm:YAG), including analysis of stone particle size after lithotripsy. METHODS: Human urinary stones of 7 different compositions were subjected to in vitro lithotripsy using a p-Tm:YAG laser with 270 µm silica core fibers (Thulio®, Dornier MedTech GmbH®, Wessling, Germany). A cumulative energy of 1000 J was applied to each stone using one of three laser settings: 0.1 J × 100 Hz, 0.4 J × 25 Hz and 2.0 J × 5 Hz (average power 10 W). After lithotripsy, larger remnant fragments were separated from stone dust using a previously described method depending on the floating ability of dust particles. Fragments and dust samples were then passed through laboratory sieves to evaluate stone particle count according to a semiquantitative analysis relying on a previous definition of stone dust (i.e., stone particles ≤ 250 µm). RESULTS: The p-Tm:YAG laser was able to produce stone dust from lithotripsy up to measured smallest mesh size of 63 µm in all seven stone composition types. Notably, all dust samples from all seven stone types and with all three laser settings had high counts of particles in the size range agreeing with the definition stone dust, i.e., ≤ 250 µm. CONCLUSION: This is the first study in the literature proving the p-Tm:YAG laser capable of dusting all prevailing human urinary stone compositions, with production of dust particles ≤ 250 µm. These findings are pivotal for the broader future implementation of the p-Tm:YAG in clinical routine.

Correlation of the Degree of Hydronephrosis and Computed Tomography Value of Calculi with Efficacy of Ureteroscopic Lithotripsy in Patients with Upper Urinary Tract Infectious Calculi

Objective: The correlation of the degree of hydronephrosis and computed tomography (CT) value of calculi with the efficacy of ureteroscopic lithotripsy (URSL) in patients with upper urinary tract infectious calculi was explored. Methods: The clinical data of 152 patients with upper urinary tract infectious calculi and on URSL in Shanghai Baoshan District Wusong Central Hospital from November 2019 to November 2021 were collected for retrospective analysis. All patients received CT examination before surgery. According to the therapeutic effect of URSL, all patients were divided into the non-calculi group (NCG, n = 101) and residual calculi group (RCG, n = 51), which were compared in terms of the degree of hydronephrosis and CT value of calculi. Then, the correlation of the degree of hydronephrosis and CT value of calculi with the efficacy of URSL in patients was analysed. Results: No significant difference in clinical data was found between the groups (p > 0.05). Patients in the NCG group had lower degree of hydronephrosis than those in the RCG group (p < 0.05), and the NCG had lower CT value of calculi (p < 0.001). Spearman rank correlation analysis showed that the degree of hydronephrosis in patients with upper urinary tract infectious calculi was negatively correlated with the efficacy of URSL (r = −0.676, p < 0.001), and the CT value of calculi in such patients was negatively correlated with the efficacy of URSL (r = −0.795, p < 0.001). Conclusions: The degree of hydronephrosis and CT value of calculi were negatively correlated with the efficacy of URSL. Both can be used to predict clinical efficacy and have clinical guiding value for the formulation of treatment plans in patients with urinary tract infectious calculi (AU)

How did COVID-19 affect acute urolithiasis? An inner Anatolian experience.

BACKGROUND: The COVID-19 pandemic has changed the number of patients seeking medical help from the emergency service (ES) with non-COVID complaints, consequencing in postponed presentations of different surgical and medical situations. Acute urinary stone disease is one of these situations and needs to be investigated in terms of the effect of COVID-19 on its presentation to the ES. METHODS: In this observational, retrospective, and single-center study, we scanned each abdominopelvic computed tomography requested in ES for possible acute urolithiasis during 1 year before and after the outbreak of COVID-19. We searched to state the number of abdominopelvic computed tomographies applied and the number of ratifying urinary stone positivity. We enrolled patients' gender, age, stone location, and stone size. We also recorded C-reactive protein, leukocyte count, and creatinine and noted how long the patients suffering from pain, the duration until the intervention, and the management option selected for each case. RESULTS: Total number of abdominopelvic computed tomographies performed was 1089. Of these, 517 were pre-pandemic and 572 were peri-pandemic. The number of pre and peri-pandemic stone-positive scans were, respectively, 363 (70.2%) and 379 (66.2%) (P=0.643). The females' percentage in the COVID-19 period (37.2%) was significantly lower than in the pre-pandemic period (54.3%) (P=0.013). The median size of ureter stones of the pre and peri-pandemic groups were, respectively, 4.8 mm and 3.9 mm depicting no significant difference (P=0.197). No significant difference was sighted between the pre and peri-pandemic groups concerning stone locations, blood parameters, painful duration, treatment options, and time to intervention. CONCLUSION: The COVID-19 pandemic resulted in neither sicker nor fewer patients suffering from acute ureteric colic in the ES.

[Features of encrustation of ureteral stents in patients with calcium oxalate and urinary acid stones].

INTRODUCTION: Stent encrustation is one of the most difficult problems that can lead to difficulties in stent removal, while ureteral obstruction can lead to renal failure. Despite the search for various preventive measures, it still remains unresolved. AIM: To study the effect of Blemaren on stent encrustation in patients with calcium-containing and uric acid stones after ureteroscopy with lithotripsy. MATERIALS AND METHODS: A total of 60 patients with ureteral stones who underwent ureteroscopy with lithotripsy in A.V. Vishnevsky National Medical Research Center of Surgery from January to August 2022, were included in the study. In all cases ureteral stents 6 Ch were placed at the end of the procedure. Patients with uric acid and calcium oxalate stones (n=48) were randomized into two groups: in the main group (n=20), they were prescribed Blemaren up to the stent removal. In the control group (n=28), patients did not receive additional therapy. To determine the severity of incrustation, we used our own classification, where the percentage of lithogenic deposits relative to the lumen of the stent was calculated. Visual assessment and microscopic examination of the removed stents were performed on days 30+/-4.1 and 60+/-7.3. RESULTS: In patients of both groups, the severity of encrustation on the 30th day after stent placement was low (up to 30%). There were no significant differences between the groups (p=0.421). The main changes were detected 60 days after stent placement. Microscopic study revealed significant differences between two groups. In patients who did not receive Blemaren, microscopic signs of encrustation of the proximal curl of the stent occurred 2.5 times more often than in the main group (p=0.001). CONCLUSIONS: 1. The number of encrusted stents in patients with calcium oxalate and uric acid stones who did not receive Blemaren significantly increases after two months. 2. Upper urinary tract drainage with a stent for a period of more than 2 months is possible if clinically necessary, however, preventive measures to reduce the risk of encrustation should be applied.

Storz Medical Lithotripsy Index Predicts Success of Shock Wave Lithotripsy in Ureteric Stones.

PURPOSE: The aim of this study is to evaluate the factors affecting treatment success in patients who underwent Shock wave lithotripsy (SWL) for ureter stones and to investigate the effect of Storz Medical Lithotripsy Index (SMLI) on treatment effectiveness in ureteric stones. METHOD: Prospective data were collected on patients undergoing SWL treatment for ureter 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 with local anaesthesia. The total amount of energy applied to the stone was calculated using the Storz Medical Lithotripsy Index (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 (SF) or detection of residual fragments < 4 mm that did not require further treatment Results: A total of 1199 patients with ureter stones were included in the study. The mean age of the patients was 43.11 ± 10.65 (18-73), and the mean BMI was 27.87±8.12(19.02-38.65). During SWL, 89.3% of patients demonstrated excellent pain tolerance (1070/1199). A total of 119 patients could not tolerate pain during SWL (10.7%). Treatment success was associated with fewer treatment sessions (2.04±1.64 vs. 2.50 ± 1.48; p < 0.001), smaller stone size (7.35±2.99 vs. 9.02 ± 3.81; p < 0.001) and higher SMLI/stone size (29.70 ± 17.48 vs. 24.98±16.01; p < 0.001). In the univariate and multivariate regression analysis, the factors affecting the success of the treatment were the number of sessions (OR: 1.147), stone size (OR: 1.112), SMLI/stone size (OR: 1.115) and pain tolerance (OR: 0.740). CONCLUSION: In the treatment of ureteral stones with SWL, number of sessions, 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.

How I Do It: Ureteroscopy and high-power holmium laser lithotripsy to treat renal stones.

In North America, ureteroscopy has become the most popular treatment modality for upper urinary tract urinary calculi. Herein we describe our technique for the treatment of renal stones with flexible ureteroscopy and high-power holmium laser lithotripsy. We discuss preoperative planning, intraoperative strategies, and laser settings for a high-frequency dusting technique with the goal to provide optimal patient outcomes.

Microureteroscopy in the treatment of upper urinary tract stones in pediatric patients younger than 3 years of age.

The aim of this study is to evaluate the usefulness of microureteroscopy (m-URS) in the treatment of renal and ureteral stones in children younger than 3 years of age. A retrospective analysis of pediatric patients aged < 3 years with upper urinary tract calculi who underwent lithotripsy was performed. The children were divided into the m-URS group (4.85 F, n = 41) and the ureteroscopy (URS) group (4.5/6.5 F, n = 42) according to the type of ureteroscope used. The mean age of the patients was 23.5 ± 10.7 months in the m-URS group and 20.6 ± 7.1 months in the URS group (P = 0.212). The success rate of one-stage surgery was 80.5% (33/41) for m-URS and 38.1% (16/42) for URS (P < 0.001). The success rates of m-URS were 60.0%, 69.2%, and 91.3% for stones located in the renal pelvis/calix, upper ureter, and mid-lower ureter, respectively. Eight children in the m-URS group and 26 children in the URS group underwent the second-stage ureteroscopic surgery. The mean operation time was 50 (30-60) min in the m-URS group and 40 (34-60) min in the URS group (P = 0.287). The complication rates were 4.9% and 7.1% in the m-URS and URS groups, respectively (P = 1.000). The stone-free rate at 1 month after lithotripsy was 87.8% in the m-URS group and 83.3% in the URS group (P = 0.563). The mean anesthesia session was 2.1 in the m-URS group and 2.5 in the URS group (P = 0.002). M-URS can effectively reduce the number of anesthesia sessions and is considered an alternative treatment for upper urinary tract calculi in selected pediatric patients younger than 3 years of age.

Selection and Outcomes for Dissolution Therapy in Uric Acid Stones: A Systematic Review of Literature.

PURPOSE OF REVIEW: The prevalence of uric acid (UA) urolithiasis contributes significantly to global disease burden, due to high rates of recurrence and diagnostic challenges. Dissolution therapy plays a valuable role in the conservative management of UA calculi, reducing the requirement for surgical intervention. This review summarises the existing evidence for the efficacy of medical dissolution of uric acid urolithiasis. RECENT FINDINGS: A systematic search was conducted of worldwide literature according to PRISMA methodology and Cochrane standards for systematic review. Studies were included if they reported outcome data for the administration of medical therapy for the dissolution of UA calculi. A total of 1075 patients were included in the systematic review. Complete or partial dissolution of UA calculi was observed in 80.5% of patients (865/1075 patients), with 61.7% (647/1048 patients) achieving complete dissolution and 19.8% (207/1048 patients) achieving partial dissolution. A discontinuation rate of 10.2% (110/1075 patients) was noted, and 15.7% (169/1075 patients) required surgical intervention. Dissolution therapy is a safe and effective method of conservatively managing uric acid stones in the short term. Despite the significant disease burden of UA calculi, current guidelines are limited by deficiencies in the existing body of research. Further research should be undertaken to develop evidence-based clinical guidelines for diagnosis, treatment, and prevention of UA urolithiasis.

Plasma formation in holmium:YAG laser lithotripsy.

OBJECTIVES: During holmium:yttrium-aluminum-garnet (holmium:YAG) laser lithotripsy to break urinary stones, urologists frequently see flashes of light. As infrared laser pulses are invisible, what is the source of light? Here we studied the origin, characteristics, and some effects of flashes of light in laser lithotripsy. METHODS: Ultrahigh-speed video-microscopy was used to record single laser pulses at 0.2-1.0 J energy lasered with 242 µm glass-core-diameter fibers in contact with whole surgically retrieved urinary stones and hydroxyapatite (HA)-coated glass slides in air and water. Acoustic transients were measured with a hydrophone. Visible-light and infrared photodetectors resolved temporal profiles of visible-light emission and infrared-laser pulses. RESULTS: Temporal profiles of laser pulses showed intensity spikes of various duration and amplitude. The pulses were seen to produce dim light and bright sparks with submicrosecond risetime. The spark produced by the intensity spike at the beginning of laser pulse generated a shock wave in the surrounding liquid. The subsequent sparks were in a vapor bubble and generated no shock waves. Sparks enhanced absorption of laser radiation, indicative of plasma formation and optical breakdown. The occurrence and number of sparks varied even with the same urinary stone. Sparks were consistently observed at laser energy >0.5 J with HA-coated glass slides. The slides broke or cracked by cavitation with sparks in 63 ± 15% of pulses (1.0 J, N = 60). No glass-slide breakage occurred without sparks (1.0 J, N = 500). CONCLUSION: Unappreciated in previous studies, plasma formation with free-running long-pulse holmium:YAG lasers can be an additional physical mechanism of action in laser procedures.

Polycythemia with elevated erythropoietin production in a patient with a urinary stone and unilateral hydronephrosis: a case report.

BACKGROUND: Absolute polycythemia can be primary or secondary. Erythropoietin-producing diseases (for example, hypoxia) are the major cause of secondary polycythemia. There are reports of polycythemia secondary to hydronephrosis. However, to our knowledge, there is no report on polycythemia secondary to hydronephrosis due to a urinary stone. Herein, we present a case of polycythemia with an elevated erythropoietin level in a patient with a urinary stone and unilateral hydronephrosis. CASE PRESENTATION: A 57-year-old Japanese man presented with polycythemia and an elevated erythropoietin level. Erythropoietin accumulation was not due to erythropoietin secretion by a tumor as no obvious lesions were detected on contrast-enhanced computed tomography. Abdominal ultrasonography revealed a stone in the left urinary tract and renal hydronephrosis, and 2 weeks later, the patient underwent transurethral ureterolithotripsy without complications. Blood tests 2 weeks after transurethral ureterolithotripsy showed that the erythropoietin level had declined. Hemoglobin concentration decreased from 20.8 mg/dL before and immediately after transurethral ureterolithotripsy to 15.8 mg/dL 3 months after transurethral ureterolithotripsy. This case was diagnosed as erythropoietin elevation due to unilateral hydronephrosis with a urinary stone, resulting in polycythemia. CONCLUSIONS: Hydronephrosis is a common disease but is not often associated with polycythemia. Further studies are required to elucidate the mechanism and implications of elevated erythropoietin production in hydronephrosis.