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Optimising laser lithotripsy

Urinary stone disease is a major and growing medical field, with significant impact on patients’ quality of life and health. It is most commonly treated using lasers to destroy stones, and the technology has evolved rapidly over the last 30 years. This research examines lasers representing the two most commonly used technologies (Ho:YAG and thulium fibre lasers) in a bench environment, to investigate how the properties of these lasers correlate to performance outcomes. These outcomes include ablation rate (how quickly stone is destroyed), retropulsion (how much and what kind of unintended stone motion is caused) and particle size (the fragments remaining after stone destruction). This research also aims to establish robust, repeatable experimental frameworks by which other lasers can be assessed and compared.

Urological stone disease: a 5-year update of stone management using Hospital Episode Statistics.

OBJECTIVE: To reassess the trends in upper urinary tract (UUT) stone disease burden and management in the UK during the last 5 years. METHODS: The present paper is our third quinquennial analysis of trends in the management of renal stones in England. Data were collected using the Hospital Episode Statistics database for the years 2015-2020 inclusive. These were then analysed, summarized and presented. RESULTS: The number of UUT stone episodes increased by 2.2% from 86 742 in 2014-2015 to 88 632 in 2019-2020 but annual prevalence remained static at 0.14%. The number of UUT stone episodes in those of working age has remained static but increased by 9% for patients aged > 60 years (from 27 329 to 29 842). The number of shockwave lithotripsy (SWL) treatments decreased by 6.8%. There was a further increase in the use of ureteroscopy (URS) between 2015 and 2020 of 18.9%. Within this subgroup, flexible URS had the most rapid increase in use, with a rise of 20.4% from 7108 to 8558 recorded cases. Over the 20-year period from 2000 to 2020 there was a remarkable 257% increase in URS cases. There was a further decline in open surgery for UUT stone disease by 40%. Stone surgery day-case numbers have increased by 14.7% (from 31 014 to 35 566), with a corresponding decline in the number of bed days of 14.3%. Emergency cases increased by 40%, while elective cases saw a slight increase of 1.9%. CONCLUSION: The present study shows a plateauing in the prevalence of UUT stone disease in England in the last 5 years, with a move towards day-case procedures and an increase in the proportion of emergency work. For the first time in England, URS has overtaken SWL as the most common procedure for treating UUT stone disease, which might reflect patients' or physicians' preference for a more effective definitive treatment.

Local anaesthetic transperineal biopsy versus transrectal prostate biopsy in prostate cancer detection (TRANSLATE): a multicentre, randomised, controlled trial.

BACKGROUND: Prostate cancer diagnosis requires biopsy, traditionally performed under local anaesthetic with ultrasound guidance via a transrectal approach (TRUS). Local anaesthetic ultrasound-guided transperineal biopsy (LATP) is gaining popularity in this setting; however, there is uncertainty regarding prostate sampling, infection rates, tolerability, side-effects, and cost-effectiveness. TRANSLATE was a randomised clinical trial that aimed to compare detection of Gleason Grade Group (GGG) 2 or higher prostate cancer, side-effects, tolerability, and patient-reported outcomes, after LATP versus TRUS biopsy. METHODS: In this randomised clinical trial which was done at ten hospitals in the UK, patients aged 18 years or older were eligible if investigated for suspected prostate cancer based on elevated age-specific prostate-specific antigen or abnormal digital rectal examination, and if biopsy-naive having received pre-biopsy MRI on a 1·5 or higher Tesla scanner. Individuals were excluded if they had any previous prostate biopsy, extensive local disease easily detectable by any biopsy (prostate-specific antigen >50 ng/mL or entire gland replaced by tumour on MRI), symptoms of concurrent or recent urinary tract infection, history of immunocompromise, need for enhanced antibiotic prophylaxis, absent rectum, or inability to position in lithotomy. Participants were randomly assigned in a 1:1 ratio to receive LATP or TRUS biopsy, using web-based software with a randomisation sequence using a minimisation algorithm to ensure balanced allocation across biopsy groups for minimisation factors (recruitment site, and location of the MRI lesion). The primary outcome was detection of GGG 2 or higher prostate cancer, analysed in the modified intention-to-treat population (all randomly assigned to treatment who had a biopsy result available). Key secondary endpoints assessing post-biopsy adverse events were infection, bleeding, urinary and sexual function, tolerability, and patient-reported outcomes. This trial is registered with ClinicalTrials.gov (NCT05179694) and at ISRCTN (ISRCTN98159689), and is complete. FINDINGS: Between Dec 3, 2021, and Sept 26, 2023, 2078 (76%) of 2727 assessed individuals were eligible, and 1126 (41%) of 2727 agreed to participate. 1044 (93%) of the 1126 participants were White British. Participants were allocated to TRUS (n=564) or LATP (n=562) biopsy, and were followed up at time of biopsy, and at 7 days, 35 days, and 4 months post-biopsy. We found GGG 2 or higher prostate cancer in 329 (60%) of 547 participants with biopsy results randomly assigned to LATP compared with 294 (54%) of 540 participants with biopsy results randomly assigned to TRUS biopsy (odds ratio [OR] 1·32 [95% CI 1·03-1·70]; p=0·031). Infection requiring admission to hospital within 35 days post-biopsy occurred in 2 (<1%) of 562 participants in the LATP group compared with 9 (2%) of 564 in the TRUS group. No statistically significant difference was observed in the reporting of overall biopsy-related complications (LATP 454 [81%] of 562 vs TRUS 436 [77%] of 564, OR 1·23 [95% CI 0·93 to 1·65]), urinary retention requiring catheterisation (LATP 35 [6%] of 562 vs TRUS 27 [5%] of 564), urinary symptoms (median International Prostate Symptom Score: LATP 8 [IQR 4-14] vs TRUS 8 [4-13], OR 0·36 [95% CI -0·38 to 1·10]), nor sexual function (median International Index of Erectile Function score: LATP 5 [2-25] vs TRUS 8 [3-24], OR -0·60 [-1·79 to 0·58]) at 4 months after biopsy. Trial participants more commonly reported LATP biopsy to be immediately painful and embarrassing compared with TRUS (LATP 216 [38%] of 562 vs TRUS 153 [27%] of 564; OR 1·84 [95% CI 1·40 to 2·43]). Serious adverse events occurred in 14 (2%) of 562 participants in the LATP group and 25 (4%) of 564 in the TRUS group. INTERPRETATION: Among biopsy-naive individuals being investigated for possible prostate cancer, biopsy with LATP led to greater detection of GGG 2 or higher disease compared with TRUS. These findings will help to inform patients, clinicians, clinical guidelines, and policy makers regarding the important trade-offs between LATP and TRUS prostate biopsy. FUNDING: National Institute for Health and Care Research (NIHR) Health Technology Assessment.

Central Adiposity Increases Risk of Kidney Stone Disease through Effects on Serum Calcium Concentrations.

SIGNIFICANCE STATEMENT: Kidney stone disease is a common disorder with poorly understood pathophysiology. Observational and genetic studies indicate that adiposity is associated with an increased risk of kidney stone disease. However, the relative contribution of general and central adipose depots and the mechanisms by which effects of adiposity on kidney stone disease are mediated have not been defined. Using conventional and genetic epidemiological techniques, we demonstrate that general and central adiposity are independently associated with kidney stone disease. In addition, one mechanism by which central adiposity increases risk of kidney stone disease is by increasing serum calcium concentration. Therapies targeting adipose depots may affect calcium homeostasis and help to prevent kidney stone disease. BACKGROUND: Kidney stone disease affects approximately 10% of individuals in their lifetime and is frequently recurrent. The disease is linked to obesity, but the mechanisms mediating this association are uncertain. METHODS: Associations of adiposity and incident kidney stone disease were assessed in the UK Biobank over a mean of 11.6 years/person. Genome-wide association studies and Mendelian randomization (MR) analyses were undertaken in the UK Biobank, FinnGen, and in meta-analyzed cohorts to identify factors that affect kidney stone disease risk. RESULTS: Observational analyses on UK Biobank data demonstrated that increasing central and general adiposity is independently associated with incident kidney stone formation. Multivariable MR, using meta-analyzed UK Biobank and FinnGen data, established that risk of kidney stone disease increases by approximately 21% per one standard deviation increase in body mass index (BMI, a marker of general adiposity) independent of waist-to-hip ratio (WHR, a marker of central adiposity) and approximately 24% per one standard deviation increase of WHR independent of BMI. Genetic analyses indicate that higher WHR, but not higher BMI, increases risk of kidney stone disease by elevating adjusted serum calcium concentrations (β=0.12 mmol/L); WHR mediates 12%-15% of its effect on kidney stone risk in this way. CONCLUSIONS: Our study indicates that visceral adipose depots elevate serum calcium concentrations, resulting in increased risk of kidney stone disease. These findings highlight the importance of weight loss in individuals with recurrent kidney stones and suggest that therapies targeting adipose depots may affect calcium homeostasis and contribute to prevention of kidney stone disease.

The association of pre-operative home accelerometry with cardiopulmonary exercise variables.

We investigated the association of pre-operative activity, reported by the Duke Activity Score Index, Short Form-12 and measured by an accelerometer worn at home, with five cardiopulmonary exercise variables: peak power; peak oxygen consumption; anaerobic threshold; and ventilatory equivalents for oxygen and carbon dioxide. Fifty patients scheduled for major surgery underwent a standard pre-operative cardiopulmonary exercise test and wore a chest-mounted triaxial accelerometer for a mean (SD) duration of 3.2 (0.4) days. The Duke Activity Score Index and six accelerometer variables were significantly correlated with all five cardiopulmonary exercise variables, Pearson correlation coefficients 0.5-0.7, p = 0.02 to p 

CT Texture Analysis of Ex Vivo Renal Stones Predicts Ease of Fragmentation with Shockwave Lithotripsy.

INTRODUCTION: Understanding the factors affecting success of extracorporeal shockwave lithotripsy (SWL) would improve informed decision-making on the most appropriate treatment modality for an individual patient. Although stone size and skin-to-stone distance do correlate with fragmentation efficacy, it has been shown that stone composition and architecture, as reflected by structural heterogeneity on CT, are also important factors. This study aims to determine if CT texture analysis (CTTA), a novel, nondestructive, and objective tool that generates statistical metrics reflecting stone heterogeneity, could have utility in predicting likelihood of SWL success. MATERIALS AND METHODS: Seven spontaneously passed, intact renal tract stones, were scanned ex vivo using standard CT KUB and micro-CT. The stones were then fragmented in vitro using a clinical lithotripter, after which, chemical composition analysis was performed. CTTA was used to generate a number of metrics that were correlated to the number of shocks needed to fragment the stone. RESULTS: CTTA metrics reflected stone characteristics and composition, and predicted ease of SWL fragmentation. The strongest correlation with number of shocks required to fragment the stone was mean Hounsfield unit (HU) density (r = 0.806, p = 0.028) and a CTTA metric measuring the entropy of the pixel distribution of the stone image (r = 0.804, p = 0.039). Using multiple linear regression analysis, the best model showed that CTTA metrics of entropy and kurtosis could predict 92% of the outcome of number of shocks needed to fragment the stone. This was superior to using stone volume or density. CONCLUSIONS: CTTA metrics entropy and kurtosis have been shown in this experimental ex vivo setting to strongly predict fragmentation by SWL. This warrants further investigation in a larger clinical study for the contribution of CT textural metrics as a measure of stone heterogeneity, along with other known clinical factors, to predict likelihood of SWL success.

The Preoperative Assessment and Optimization of Patients Undergoing Major Urological Surgery.

PURPOSE OF REVIEW: Improving patient outcomes from major urological surgery requires not only advancement in surgical technique and technology, but also the practice of patient-centered, multidisciplinary, and integrated medical care of these patients from the moment of contemplation of surgery until full recovery. This review examines the evidence for recent developments in preoperative assessment and optimization that is of relevance to major urological surgery. RECENT FINDINGS: Current perioperative medicine recommendations aim to improve the short-term safety and long-term effectiveness of surgical treatments by the delivery of multidisciplinary integrated medical care. New strategies to deliver this aim include preoperative risk stratification using a frailty index and cardiopulmonary exercise testing for patients undergoing intra-abdominal surgery (including radical cystectomy), preoperative management of iron deficiency and anemia, and preoperative exercise intervention. Proof of the utility and validity for improving surgical outcomes through advances in preoperative care is still evolving. Evidence-based developments in this field are likely to benefit patients undergoing major urological surgery, but further research targeted at high-risk patients undergoing specific urological operations is required.

Routine Antibiotic Prophylaxis Is Not Required for Patients Undergoing Shockwave Lithotripsy: Outcomes from a National Shockwave Lithotripsy Database in New Zealand.

PURPOSE: To assess the effectiveness of routine prophylactic antibiotics in the prevention of urinary tract infection (UTI) after extracorporeal shockwave lithotripsy (SWL) and identify predictors of UTI development in a multicenter series of over 10,000 stone cases treated in New Zealand over a 20-year period. MATERIALS AND METHODS: Patients treated with SWL on the Mobile Medical Technology vehicle between June 19, 1995 and December 1, 2014 were identified. Data collection was undertaken prospectively for patient, stone and treatment characteristics, and, retrospectively, for treatment outcomes. The primary outcome was clinical UTI, defined as development of UTI symptoms requiring antibiotic therapy. Secondary outcomes included urinary sepsis, need for hospital admission due to infectious complications, and length of hospital stay. Multivariate analysis was undertaken to identify factors independently associated with the development of post-SWL UTI. RESULTS: Antibiotic prophylaxis was used in 62.1% (n = 6710) of cases. On comparing patients who received prophylactic antibiotics to those in whom antibiotics were withheld, no significant differences were observed in terms of post-SWL UTI (1.1% vs 1.3%, p = 0.335) or urinary sepsis (0.04% vs 0.15%, p = 0.075). The use of prophylactic antibiotics was not independently associated with post-SWL UTI (OR: 1.269, 95% CI: 0.886-1.818, p = 0.194). Female gender, larger stone size, and higher number of delivered shocks were predictive of UTI development, but antibiotic prophylaxis did not appear to offer any benefit in this subgroup. CONCLUSIONS: Routine antibiotic prophylaxis was not associated with a reduction in clinical UTI after SWL in this cohort of over 10,000 stone cases in New Zealand.

In Vitro Assessment of Three Clinical Lithotripters Employing Different Shock Wave Generators.

OBJECTIVE: To test the hypothesis that shock wave lithotripsy machines vary in their ability to fragment standardized artificial urinary calculi. MATERIALS AND METHODS: An in vitro test configuration was used to fragment synthetic U-30 Gypsum (U.S. Gypsum, Chicago, IL) stones (mean length 7.1 ± 0.2 mm, mean diameter 6.5 ± 0.07 mm, mean mass 299 ± 16 mg) using the Sonolith i-sys (EDAP TMS, Vaulx-en-Velin, France), Modulith SLX F2 (Storz Medical AG, Tägerwilen, Switzerland), and Piezolith 3000 (Richard Wolf GmbH, Knittlingen, Germany) lithotripters. Gypsum stones were placed at the nominal focus and treated with 250, 500, or 1000 shocks. The residual mass following passage through a 2-mm wire mesh was measured and compared using ANOVA and the Tukey-Kramer HSD test. RESULTS: There was no statistically significant difference between the Modulith SLX F2 and Piezolith 3000 lithotripters for 250 and 1000 shock treatments (p = 0.34 and 0.31, respectively). The Piezolith 3000 demonstrated the most favorable stone mass reduction for 500 shock treatments (187.4 ± 45.2 mg). The Sonolith i-sys was found to be significantly less effective than the other lithotripters for all shockwave conditions. Furthermore, performance of the Sonolith i-sys decreased beyond a threshold generator electrode age of 6000 shocks. CONCLUSIONS: This in vitro study found considerable variability in the ability of lithotripters to fragment synthetic urinary calculi. Synthetic stones were employed to provide a repeatable means of assessing variability in fragmentation efficiency of lithotripters. The Modulith SLX F2 and Piezolith 3000 are broadly equal and resulted in greater fragmentation efficiencies than the Sonolith i-sys. The performance of the Sonolith i-sys deteriorates at 6000 shocks, before the specified lifetime of 20,000 shocks.

Proteomic changes in response to crystal formation in Drosophila Malpighian tubules.

Kidney stone disease is a major health burden with a complex and poorly understood pathophysiology. Drosophila Malpighian tubules have been shown to resemble human renal tubules in their physiological function. Herein, we have used Drosophila as a model to study the proteomic response to crystal formation induced by dietary manipulation in Malpighian tubules. Wild-type male flies were reared in parallel groups on standard medium supplemented with lithogenic agents: control, Sodium Oxalate (NaOx) and Ethylene Glycol (EG). Malpighian tubules were dissected after 2 weeks to visualize crystals with polarized light microscopy. The parallel group was dissected for protein extraction. A new method of Gel Assisted Sample Preparation (GASP) was used for protein extraction. Differentially abundant proteins (p<0.05) were identified by label-free quantitative proteomic analysis in flies fed with NaOx and EG diet compared with control. Their molecular functions were further screened for transmembrane ion transporter, calcium or zinc ion binder. Among these, 11 candidate proteins were shortlisted in NaOx diet and 16 proteins in EG diet. We concluded that GASP is a proteomic sample preparation method that can be applied to individual Drosophila Malpighian tubules. Our results may further increase the understanding of the pathophysiology of human kidney stone disease.

Trends in urological stone disease: a 5-year update of hospital episode statistics.

OBJECTIVE: To provide a 5-year follow-on update on the changes in prevalence and treatment of upper urinary tract (UUT) stone disease in England. METHODS: Data from the Hospital Episode Statistics (HES) website (http://www.hesonline.nhs.uk) were extracted, summarised, analysed, and presented. RESULTS: The total number of UUT stone hospital episodes increased slightly from 83 050 in 2009-2010 to 86 742 in 2014-2015 (4.4% increase). The use of shockwave lithotripsy (SWL) for treating all UUT stones remained stable over the 5-year study period following a significant increase in previous years. There was a 49.6% increase in the number of ureteroscopic stone treatments from 12 062 in 2009-2010 to 18 055 in 2014-2015. Increase in ureterorenoscopy (flexible ureteroscopy) showed the most rapid increase from 3 267 to 6 631 cases in the 5-year study period (103% increase). The gap between the total number of ureteroscopies and SWL treatments continues to narrow. Open stone surgery continued to decline with only 30 reported cases in 2014-2015. Due to the continued rapid increase in the number of ureteroscopies performed, treatment for stone disease has continued to increase significantly in comparison to other urological activity. CONCLUSION: This study provides an update on the changing landscape of the management of UUT stones in England. It shows a sustained high prevalence of stone disease commensurate with levels in other developed countries. This study reveals a trend in the last 5 years to surgically intervene on a higher proportion of patients with stones. As in other countries, there is a significant increase in the use of ureteroscopy (particularly intrarenal flexible ureteroscopy) in England. These data have important implications for work-force planning, training, service delivery, and research in the field of urolithiasis.

The success of shock wave lithotripsy (SWL) in treating moderate-sized (10-20 mm) renal stones.

Many centres favour endourological management over shock wave lithotripsy (SWL) in the management of moderate-sized (10-20 mm) renal stones. International guidelines support all available modalities for the treatment of these stones. The aim of this study was to evaluate the efficacy of SWL in the treatment of 10- to 20-mm renal stones. From January 2013 to October 2014, all patients with a renal stone measuring between 10 and 20 mm in maximum diameter on CT scan that were eligible for lithotripsy were included. 130 consecutive patients were evaluated. Demographics, location of stone within the kidney, number of SWL sessions and treatment outcomes were analysed. Treatment success was classified into complete stone clearance and the presence of clinically insignificant residual fragments <4 mm (CIRF). 119 patients (92 %) completed treatment and radiological follow-up. Eleven patients were excluded due to incomplete follow-up data. The mean age was 56.8 (23-88). Male to female ratio was 1.9:1 (78:41) and the mean BMI was 28.4 (17.9-58). The mean stone size was 12.8 mm (10-14 mm: n = 87; 15-20 mm: n = 32). The mean number of treatments was 2.14 and 2.82 for stones 10-14 and 15-20 mm, respectively. Overall treatment success was 66.4 % (combined complete stone clearance and CIRFs). Subdivided by stone size <15 mm and ≥15 mm, the success rate was 70.4 and 53.1 %, respectively. The treatment success by stone location was 65, 64 and 70 % for upper, middle and lower pole stones, respectively and 67 % for PUJ stones. For those who failed SWL treatment, the majority 50 % (n = 20) were managed expectantly, 42.5 % (n = 17) required URS, and 7.5 % (n = 3) required PNL. This study suggests that SWL has an efficacy for treating larger renal stones (10-20 mm) that is equivalent to success rates for smaller stones in other series. As a low-risk and non-invasive procedure SWL should be considered a first-line treatment for these stones.

The cost of stone surgery.

Obtaining patient feedback in an outpatient lithotripsy service is facilitated by use of a touch-screen tablet (iPad™) survey.

There is now a requirement for every doctor in the UK to obtain patient feedback for revalidation. This can be an onerous and time-consuming task. The objective of this study was to evaluate a novel electronic patient feedback method in an outpatient lithotripsy service setting. Between September 2013 and January 2014, 100 patients attending an outpatient lithotripsy service in Oxford were asked to complete a selection of pre-approved NHS questions about the service they had received. Questions were presented on a tablet device (iPad™) and answered using the touch screen. Departmental staff were unaware of the questions in the survey. Patients were asked to complete the survey by an independent research nurse. Questions were created online in a free-to-use web-based survey application and presented on the tablet device in a user-friendly format via an application. Data were uploaded via wifi™ to the online system. Data were viewed, automatically analysed and displayed graphically. The age range of the patients surveyed was 20-80 years of age. All 100 patients completed the survey without difficulty. All patients answered every question. Data could be automatically viewed, analysed and presented graphically. This method of collecting patient feedback proved to be rapid and efficient. The feedback highlighted a high patient satisfaction with the lithotripsy service. A touch screen tablet device is an efficient and effective method of collecting truly objective patient feedback. This method of patient feedback could be employed in other clinical environments to collect data for revalidation purposes.

Would You Want to Be the Patient? "Live Surgical Broadcast" or "As-Live Unedited Surgical Broadcast".

OBJECTIVE: To evaluate patient safety, educational value, and ethical issues surrounding "Live surgical broadcast" (LSB) and "As-live surgical broadcast" (ALB) using data obtained from urologic delegates attending two recent endourology meetings in the United Kingdom. SUBJECTS AND METHODS: Two hundred twelve delegates at the UK section meeting of the Société Internationale d'Urologie (SIU) were invited to complete an online survey using SurveyMonkey(®) to compare their previous perceptions of LSB and ALB, and to compare their current experience of ALB to previous experience of LSB. One hundred three delegates at the British Association of Urological Surgeons (BAUS) Endourology meeting used live voting keypads to compare their experience of LSB and ALB simultaneously, as well as comparing their current experience of ALB to previous experience of LSB. Responses were recorded using a Likert scale. RESULTS: One hundred sixty-five responses were analyzed from the meetings. Most delegates were in specialist practice as a consultant or trainee (89.1%). LSB had been witnessed more than ALB (87.1% vs 66.6%, p=0.049). Based on previous experiences, the educational value of both formats was felt similar, but delegates felt there were significant patient safety benefits with ALB over LSB. Delegates were significantly less likely to recommend a friend or family, or volunteer themselves to be a patient in an LSB setting. On-the-day comparison of LSB and ALB shows a similar educational value to both formats, but with significantly less concern for the surgeon and patient's outcome with ALB. CONCLUSION: ALB offers similar educational opportunities to delegates when compared with LSB, while appearing to offer significant welfare benefits to both surgeon and patient. Further studies are required to objectively quantify these subjective observations.

Diet and risk of kidney stones in the Oxford cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC).

The lifetime prevalence of kidney stones is around 10 % and incidence rates are increasing. Diet may be an important determinant of kidney stone development. Our objective was to investigate the association between diet and kidney stone risk in a population with a wide range of diets. This association was examined among 51,336 participants in the Oxford arm of the European Prospective Investigation into Cancer and Nutrition using data from Hospital Episode Statistics in England and Scottish Morbidity Records. In the cohort, 303 participants attended hospital with a new kidney stone episode. Cox proportional hazards regression was performed to calculate hazard ratios (HR) and their 95 % confidence intervals (95 % CI). Compared to those with high intake of meat (>100 g/day), the HR estimates for moderate meat-eaters (50-99 g/day), low meat-eaters (<50 g/day), fish-eaters and vegetarians were 0.80 (95 % CI 0.57-1.11), 0.52 (95 % CI 0.35-0.8), 0.73 (95 % CI 0.48-1.11) and 0.69 (95 % CI 0.48-0.98), respectively. High intakes of fresh fruit, fibre from wholegrain cereals and magnesium were also associated with a lower risk of kidney stone formation. A high intake of zinc was associated with a higher risk. In conclusion, vegetarians have a lower risk of developing kidney stones compared with those who eat a high meat diet. This information may be important to advise the public about prevention of kidney stone formation.

Shock-wave lithotripsy: variance within UK practice.

The objectives of this study are to determine the current treatment policies of UK shock-wave lithotripsy centres. Fixed-site lithotripter centres in the UK were identified via the national Therapeutic Interventions for Stones of the Ureter (TISU) study (n = 25). Questionnaires were completed regarding current SWL protocols for each centre, including management of anticoagulation, use of antibiotics and analgesia, urine testing, pacemakers, and arterial aneurysms. Data were collected regarding service delivery. Responses were obtained for 21 centres. Most centres use the Storz Modulith (85.7 %). Wide variation was observed in clinical contraindications to SWL, with 47.6 % centres performing SWL in patients with an abdominal aortic aneurysm, 66.7 % performing SWL in patients with a pacemaker, and 66.7 % of centres not performing SWL in asymptomatic patients with a urine dipstick positive for nitrites and leucocytes. The management of anticoagulation pre- and post-SWL showed wide variation, with the omission of anticoagulation ranging from 0 to 10 days pre-SWL. Seventeen distinct analgesia regimens were reported and prophylactic antibiotics are routinely administered in 25.0 % of centres. Tamsulosin is prescribed to all patients in 20.0 % of centres and a further 15.0 % of centres routinely prescribe tamsulosin post-SWL of ureteric stones. The included centres undertake SWL a median of 4 days per week and treat a median of six patients per list. Emergency SWL is unavailable in 30.0 % of centres. This observational real-life study has identified a significant disparity in the delivery of SWL throughout the UK, despite high numbers of patients with renal and ureteric stones being treated with this modality. Further studies should address the key areas of controversy, including an assessment of technical training, and facilitate the development of national guidelines to ensure a high level of standardized care for SWL patients.

Shock wave lithotripsy (SWL): outcomes from a national SWL database in New Zealand.

OBJECTIVES: To present the national outcomes for New Zealand of over 9000 stone cases treated with SWL at 21 centres over a 20 year period. SUBJECTS/PATIENTS AND METHODS: Stone cases treated with SWL on board the Mobile Medical Technology (MMT) vehicle between 19 June 1995 and 1 December 2014 were identified, and data collection undertaken prospectively for patient, stone and treatment characteristics, and retrospectively for treatment outcomes. The primary outcome was treatment success, defined as complete stone clearance or clinically insignificant residual fragments (CIRFs) of ≤4 mm. Secondary outcomes were stone free rate, complications and auxiliary procedures, and all statistical analyses were descriptive. RESULTS: 9538 stone cases (7769 patients) were included. The overall, cumulative success rate was 58.7%; this included 45.1% that were stone free and 13.5% in which there were CIRFs ≤4 mm. Success rates varied widely by stone size and location. Overall rates of urinary tract infection, perinephric haematoma, hospital admission and ureteral stent placement were 1.1%, 0.2%, 6.8% and 4.1%, respectively. Variations in SWL protocols across centres limits the overall reliability of our findings. CONCLUSION: SWL remains a low morbidity management option requiring careful patient selection. This study provides valuable data for patient counseling and the formation of evidence based guidelines in SWL. The MMT SWL service has demonstrated that is it possible to deliver a high volume specialist stone service without requiring patients to travel further for treatment.

Quantification of the Range of Motion of Kidney and Ureteral Stones During Shockwave Lithotripsy in Conscious Patients.

Effective shockwave lithotripsy requires accurate targeting of the stone throughout the course of treatment. Stone movement secondary to respiratory movement can make this more difficult. In vitro work has shown that stone motion outside the focal region reduces the efficacy of stone fragmentation; however, there are few clinical data on the degree of stone movement in patients during treatment. To investigate this, X-ray fluoroscopic images of the kidney and ureteral stones at the upper and lower limits of the normal respiratory cycle were acquired during shock wave lithotripsy of 58 conscious patients, and stone excursion was calculated from these images. In addition, the respiration rate and patient perceived pain were recorded during the course of the treatment. It was found that stone motion secondary to respiration was 7.7 ± 2.9 mm for kidney stones and 3.6 ± 2.1 mm for ureteral stones-less than has been reported in studies with anesthetized patients. There was no significant change of motion over the course of treatment although pain was found to increase. These data suggest that stone motion in conscious patients is less than in anesthetized patients. Furthermore, it suggests that lithotripters with focal regions of 8 mm or greater should not suffer from a marked drop in fragmentation efficiency due to stone motion.

EVALUATION OF THE DIAGNOSTIC ACCURACY OF MULTIDETECTOR COMPUTER TOMOGRAPHY UROGRAPHY (MDCTU) FOR DIAGNOSING BLADDER CANCER IN PATIENTS PRESENTING WITH MACROSCOPIC HAEMATURIA OVER 40 YEARS OF AGE