Fragmentation Of Calculi Research Articles

Endoscopic management of chronic pancreatitis.

Chronic pancreatitis (CP) is an inflammatory process characterized by irreversible morphological changes in the pancreas. Pain is the predominant symptom observed during the course of CP. The etiopathogenesis of pain in CP is multifactorial and includes ductal hypertension due to obstruction of the pancreatic duct (PD), neuropathic causes, and extrapancreatic complications of CP like pseudocyst and distal biliary obstruction. A sizeable proportion of patients with CP are amenable to endoscopic treatment. The mainstay of endotherapy includes decompression of PD with one or more plastic stents in those with stricture, and fragmentation of PD calculi using extracorporeal shock wave lithotripsy. Nearly two-thirds of the patients achieve pain relief in the long term with endotherapy. Upfront assessment for the suitability of endotherapy is paramount to achieve the best outcomes. The predictors of poor response to endotherapy include multifocal disease, like those with multifocal strictures or multiple calculi throughout the pancreas, or a combination of both PD strictures and stones. With the emerging use of covered metal stents, the outcomes are likely to improve in cases with refractory PD strictures as well as CP-related distal biliary obstruction. The optimum stent design and indwell time of metal stents in cases with refractory PD strictures need further evaluation. Endoscopic ultrasonography has emerged as a complementary endoscopic modality in the management of CP as well as associated complications like pseudocysts, refractory pain, and vascular complications.

Porosity in Microtomography and Determination of Hounsfield Units do not Predict Calculi Fragmentation in Extracorporeal Lithotripsy: Analysis of an In-vitro Study

Background: Extracorporeal Shock Wave Lithotripsy (SWL) remains one of the most popular methods for treating urinary lithiasis. Objective: To evaluate structural and microtomographic characteristics associated with urinary calculi fragmentation in an experimental model of SWL. Methods: Samples consisting of at least two calculi fragments obtained from patients were submitted to urological procedures. All calculi were analyzed by X-ray diffraction and a morphological evaluation (weight, length, width, and volume measurements) was conducted along with microtomographic and conventional tomographic assessments in vitro. Thereafter, each sample was submitted to SWL in a ballistic gelatin model. The fragments were separated, using a granulometric sieve, into specimens larger than 4 mm and 2 mm, which were subsequently weighed. Results: Altogether, 48 urinary calculi were analyzed and were composed of whewellite (54%), struvite (22%), apatite (11%), uric acid (7%), cystine (4%), and whitlockite (2%). The fragmentation rate was 77.5% and 69.6% for samples > 4 mm and > 2 mm in size, respectively. Factors associated with a reduction in the effectiveness of SWL were volume, dry mass, and width of the calculus. The radiodensity and porosity of the samples evaluated by microtomography were not associated with the fragmentation of calculi. Conclusion: The volume, dry mass, and width of urinary calculi were positively correlated with the number of fragments larger than 4 and 2 mm in size obtained post-SWL.

Combined lithotripsy of mechanical clamping and electrohydraulics in facilitating endoscopic management of refractory residual biliary calculi after surgery

Although postoperative cholangioscopy (POC) guided electrohydraulic lithotripsy (EHL) is considered to be a conventional technique for residual biliary calculi, its efficacy still needs to be improved to fit in the managemet of refractory calculi. This study evaluated the efficacy and safety of combined lithotripsy of mechanical clamping and electrohydraulics in fragmentation and removal of refractory calculi. Totally, 281 patients, who suffered from residual biliary calculi after hepatectomy and underwnet POC from August 2016 to June 2018 were involved. The first 128 patients were subjected to conventional EHL, and later consective 153 to combined lithotripsyof mechanical clamping and EHL. Perioperative data, technical information, treatment outcomes and follow-up results were collected. Clinical characteristics were statistically comparable (P > 0.05). The overall POC interventional sessions (2.0 ± 0.65 vs. 2.9 ± 1.21 sessions), average operating time (99.1 ± 34.88 vs. 128.6 ± 72.87 minutes), incidence of intraoperative hemobilia (4.58% vs. 10.93%), cholangitis (6.54% vs. 14.06%), postoperative complications (10.45% vs. 21.87%), T-tube retaining time after first POC (20.7 ± 5.35 vs. 28.1 ± 8.28 days), and treatment costs ($2375 ± 661.72 vs. $3456.7 ± 638.07) were significantly lower in the combined lithotripsy group than those in the EHL group (P < 0.05). There were no differences between the two groups in calculi recurrence at half-a year, or one year follow-up. In conclusion, combined lithotripsy of mechanical clamping and electrohydraulics can safely and effectively benefit postoperative patients along with refractory residual biliary calculi.

PNEUMATIC CONTACT TRANSURETHRAL ureterOLITHOTRIPSY in emergency urological practice

Relevance. Minimally invasive methods of removing the ureteral calculus in urological practice have steadily taken the leading position. According to the Russian clinical recommendations the indications for endoscopic correction of ureteral calculus are concrements with a low probable passage, constant pain symptomatic on the background of adequate analgesia, the varying degrees of obstruction severity and impaired renal function. The purpose of the work is to assess the efficacy of transurethral pneumatic contact lithotripsy of ureteral calculus in emergency urological practice. The research tasks included the refinement of the endoscopic lithotripsy results, depending on the localization level among men and women. Materials and methods. The results of endoscopic treatment of ureteral calculus among 360 patients of both sexes, hospitalized in a urological hospital with emergency indications of a renal colic diagnosis, are presented. Results. The efficiency of retrograde pneumatic contact ureterolithotripsy reached 91.8 %. The most optimal this method is with the localization of calculus in the lower third of the ureter, regardless of the concrement size and sex. The percentage of the calculus fragmentation of the middle third of the ureter among men and women was 91.6 and 93.4 respectively. The lithotripsy in the upper part of the ureter was 23.6 % more effective among women. Operational complications were registered in 7.5 % cases.

The prediction of urinary calculi fragmentation duration under the holmium laser pulses

The results of settlement-experimental definition (prediction) of urinary stones fragmentation duration by the holmium laser impulses with the wavelength of 2.1 microns and energy from 0.8 to 1.6 J are presented in the paper. The obtained analytical expressions allow to estimate the duration of urinary stone complete fraction on the basis of its volume and radiological density as well as on its location, comprising the auxiliary manipulations time, and to predict lithotripsy operation duration regarding this data.

Summary of "Biomedical Acoustics and Physical Acoustics: Shock Waves and Ultrasound for Calculus Fragmentation".

This paper summarizes the special session, "Shock Waves and Ultrasound for Calculus Fragmentation," that took place during the 176th Meeting of the Acoustical Society of America and 2018 Acoustics Week in Canada. The sessions were cosponsored by the Biomedical Acoustics and Physical Acoustics Technical Committees and consisted of ten talks by industry and academic researchers from institutions in the United States, France, and the Russian Federation. The sessions described basic and applied acoustic research to manage urinary stones.

Predictive Value of Hounsfield Unit, Volumetric Stone Burden in Fragmentation and Specific Composition of Urinary Calculi

Predictive Value of Hounsfield Unit, Volumetric Stone Burden in Fragmentation and Specific Composition of Urinary Calculi

Use of a laparoscopic specimen retrieval pouch to facilitate removal of intact or fragmented cystic calculi from standing sedated horses: 8 cases (2012-2015).

OBJECTIVE To evaluate the use of a laparoscopic specimen retrieval pouch for removal of intact or fragmented cystic calculi from standing horses. DESIGN Retrospective case series. ANIMALS 8 horses (5 geldings and 3 mares) with cystic calculi. PROCEDURES Physical examination and cystoscopic, ultrasonographic, and hematologic evaluations of urinary tract function were performed for each horse. A diagnosis of cystic calculus was made on the basis of results of cystoscopy and ultrasonography. Concurrent urolithiasis or other urinary tract abnormalities identified during preoperative evaluation were recorded. Horses were sedated and placed in standing stocks, and the perineum was aseptically prepared. Direct access to the urinary bladder was gained in geldings via perineal urethrotomy or in mares by a transurethral approach. Calculi were visualized endoscopically, manipulated into the retrieval pouch, and removed intact or fragmented (for larger calculi). RESULTS For 4 geldings and 1 mare, fragmentation was necessary to facilitate calculus removal. Mean duration of surgery was 125 minutes, and trauma to the urinary bladder and urethra was limited to areas of hyperemia and submucosal petechiation. No postoperative complications were encountered for any horse. When lithotripsy was required, the retrieval pouch provided an effective means of stabilizing calculi and containing the fragments for removal. CONCLUSIONS AND CLINICAL RELEVANCE Use of the laparoscopic specimen retrieval pouch was an effective, minimally traumatic method for retrieving cystic calculi from standing horses. The pouch protected the urinary bladder and urethra from trauma during calculus removal and allowed for stabilization, containment, and fragmentation of calculi when necessary.

Salivary Stone Pneumatic Lithotripsy in a Live Porcine Model.

The purpose of this study is to evaluate the efficacy of endoscopic fragmentation and removal of artificial calculi in a live porcine model employing intracorporeal pneumatic lithotripsy. In this experimental study, 7 submandibular ducts were accessed and artificial calculi placed. A salivary pneumatic lithotripter probe was inserted through an interventional sialendoscope to fragment the calculi. A salivary duct catheter was then used to flush stone fragments, followed by endoscopy to assess complete fragmentation and ductal trauma. Ultimately, 7 artificial stones (3-10 mm, 4F/5F) were successfully fragmented without causing significant endoluminal trauma. Number of pulses for adequate stone fragmentation averaged 20 (range, 5-31). In all cases, stone fragments were successfully flushed out with the salivary duct catheter. Postprocedure endoscopy confirmed ductal integrity in all 7 ducts. While more studies are needed, this preliminary animal model demonstrates efficacy of endoscopic pneumatic lithotripsy for the management of sialolithiasis.

Feasibility study on a short-pulsed IR wavelength for effective calculus fragmentation

Laser-induced lithotripsy has been used for a minimally-invasive surgery to treat kidney-stone disease associated with urinary obstruction. A short-pulsed Tm:YAG laser (λ = 2.01 µm) was developed to improve fragmentation efficiency and was evaluated with a Ho:YAG laser (λ = 2.12 μm) as to its ablation feature and mass removal rate. Application of a train of sub-microsecond pulses with a lower energy at a frequency of 500 Hz created multiple events of cavitation that accompanied strong acoustic transients. During Tm:YAG irradiation, both high light absorption and secondary photomechanical impacts readily fragmented the calculus into small pieces (< 3 mm) and removed them 130 times faster than photothermal Ho:YAG lithotripsy. The proposed short-pulsed Tm:YAG approach may be an effective lithotripter for treating calculus disease.

Impact of Renal Anatomy on Shock Wave Lithotripsy Outcomes for Lower Pole Kidney Stones: Results of a Prospective Multifactorial Analysis Controlled by Computerized Tomography

We evaluated which variables impact fragmentation and clearance of lower pole calculi after shock wave lithotripsy. We prospectively evaluated patients undergoing shock wave lithotripsy for a solitary 5 to 20 mm lower pole kidney stone between June 2012 and August 2014. Patient body mass index and abdominal waist circumference were recorded. One radiologist blinded to shock wave lithotripsy outcomes measured stone size, area and density, stone-to-skin distance, infundibular length, width and height, and infundibulopelvic angle based on baseline noncontrast computerized tomography. Fragmentation, success (defined as residual fragments less than 4 mm in asymptomatic patients) and the stone-free rate were evaluated by noncontrast computerized tomography 12 weeks postoperatively. Univariate and multivariate analysis was performed. A total of 100 patients were enrolled in the study. Mean stone size was 9.1 mm. Overall fragmentation, success and stone-free rates were 76%, 54% and 37%, respectively. On logistic regression body mass index (OR 1.27, 95% CI 1.11-1.49, p = 0.004) and stone density (OR 1.0026, 95% CI 1.0008-1.0046, p = 0.005) significantly impacted fragmentation. Stone size (OR 1.24, 95% CI 1.07-1.48, p = 0.039) and stone density (OR 1.0021, 95% CI 1.0007-1.0037, p = 0.012) impacted the success rate while stone size (OR 1.24, 95% CI 1.04-1.50, p = 0.029), stone density (OR 1.0015, 95% CI 1.0001-1.0032, p = 0.046) and infundibular length (OR 1.1035, 95% CI 1.015-1.217, p = 0.015) impacted the stone-free rate. The best outcomes were found in patients with a body mass index of 30 kg/m(2) or less, stones 10 mm or less and 900 HU or less, and an infundibular length of 25 mm or less. The coexistence of significant unfavorable variables led to a stone-free rate of less than 20%. Obese patients with higher than 10 mm density stones (greater than 900 HU) in the lower pole of the kidney with an infundibular length of greater than 25 mm should be discouraged from undergoing shock wave lithotripsy.

This Month in Investigative Urology

No AccessJournal of UrologyThis Month in Investigative Urology1 Jan 2015This Month in Investigative Urology Karl-Erik Andersson Karl-Erik AnderssonKarl-Erik Andersson More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.10.054AboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail "This Month in Investigative Urology." The Journal of Urology, 193(1), pp. 6–7 References 1 : Circulating serum miRNA (miR-367-3p, miR-371a-3p, miR-372-3p and miR-373-3p) as biomarkers in patients with testicular germ cell cancer. J Urol2015; 193: 331. Link, Google Scholar 2 : Fragmentation of urinary calculi in vitro by burst wave lithotripsy. J Urol2015; 193: 338. Link, Google Scholar 3 : Expression and role of leptin under hypoxic conditions in human testis: organotypic in vitro culture experiment and clinical study on patients with varicocele. J Urol2015; 193: 360. Link, Google Scholar © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 1January 2015Page: 6-7 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Karl-Erik Andersson More articles by this author Expand All Advertisement PDF downloadLoading ...

Evaluation of the pressure leak test in increasing the lifespan of flexible ureteroscopes

Flexible ureteroscopes are expensive and delicate instruments that are integral in the offering of a minimally invasive technique of diagnosis and treatment of urolithiasis. Published literature has identified the importance of early damage recognition in preventing frequent use of the scope that would lead to further damage and high repair and replacement costs. Our study was designed to examine the outcome of the pressure leak test on the condition of flexible ureteroscopes after every use and analysing the damage and costs of maintenance. A prospective study was designed with two treatment groups. Group 1, 95 consecutive procedures (n = 95) of flexible ureterorenoscopy and laser fragmentation of renal calculi were performed with ACMI DUR 8, (a scope with no in-built leak test facility). This was compared against group 2, where 98 procedures of laser fragmentation of renal calculi (n = 98) were performed using Storz Flex X(2) Ureteroscopes (with a in-built leak test facility). All scopes in Group 2 were tested for pressure leak after every procedure and the outcome of the tests recorded. Both groups were comparable for grade of surgeon; stone location, size & number; access sheath usage and duration of lasering. In Group 1, there were seven scope damages resulting in repairs/replacement amounting to costs $46264.40 (7.1% damage). In Group 2, three scopes revealed a positive pressure leak test, implying damage with repair costs of $9952.80 (3.1% damage) (p < 0.05). Significant cost savings and reduction in downtime were made in Group 2. Pressure leak testing following flexible ureterorenoscopy helped to significantly control costs of maintenance and repair. Newer scopes should have a leak testing mechanism as it prevents further detrimental damage to the scope, build-up of repair costs are avoided and there is an increase in the longevity of these delicate instruments.

TRAITEMENT DES CALCULS URINAIRES PAR LITHOTRITIE EXTRA-CORPORELLE

Introduction : Until the begining of the eigthies, the surgery was the only way to extract calculi localised in the kidney or the ureter. The extra-corporeal lithotripsy, who allow fragmentation of calculi by schock waves, was the most important discover. Nowadays it is the most useful method for the treatement of calculi. This field knows an important development with the appearance of new machines more and more performant. The objective of this study is to evaluate the clinical results after one year’s experience with a new generation lithotriptor : the lithostar multiline tm (siemens). Materiels and methods : The authors treated 147 patients ages between the ages of 8 and 73 years, presenting with renal stones in 67,23% of cases, ureteral stones in 31,07% of cases and bladder stones in 1,69% in cases .The mean stone diameter was 14mm (3-34mm). An average of 3846 (range 1500-6000) shock waves were applied with a mean energy level of 4,29 (range : 1,5 -7) Results : The succes rate was 62% for the renal stones, 82% for lumbar ureter and 60,7% for the pelvic stones. The morbidity was low (10% of renal colic, 5% of obstructive stone and 1,4% of pyelonephritis). Conclusion : The (siemens) multiline tm lithostar is a new generation lithotriptor, efficient and with a low morbidity. These data indicates the limits of the efficacy nature of a modern lithotriptor for the pelvic stones.

Remifentanil patient controlled analgesia for patients unable to tolerate lithotripsy with enteral analgesia

Background: Extracorporeal shock wave lithotripsy is an effective treatment for kidney stones which does not require general anaesthesia and can be performed as a daycase procedure. The fragmentation of calculi can be painful and various analgesic regimens have been described. A small minority of our patients are unable to tolerate ESWL with enteral analgesia. We offered a repeat ESWL treatment with remifentanil Patient Controlled Analgesia (R-PCA) to this group. Methods: Patients were given oral paracetamol 1g and 100mg rectal diclofenac before ESWL. Remifentanil PCA was prepared to provide a 0.5mcg/kg bolus with 2 minute lockout with dose increase as necessary. The primary outcome measure was ESWL energy level tolerated and was compared between groups with the Wilcoxon signed-rank test. Secondary outcomes included pain score, sedation score and adverse effects. Results: Twenty-one patients were treated with adjuvant R-PCA for one (n=21), two (n=7) or three (n=1) ESWL sessions. All patient were able to tolerate a significantly higher ESWL power level with R-PCA compared to enteral analgesia (p<0.01). Sedation was minimal (all sedation scores ≥ 3) with a low incidence of side effects. Conclusion: Patients treated with R-PCA tolerated a significantly higher ESWL power level and all patients completed the treatment. These patients were maintained on their intended treatment modality and avoided the operative and anaesthetic risks of alternative procedures such as ureteroscopy. On demand bolus PCA allows accurate titration of opiate to pain and is safe to use with the limited resources available in the ESWL suite. The combination of this delivery method with the minimal sedation and rapid elimination of remifentanil proved effective and safe with few adverse effects.

Impact of stone density on the outcome of extracorporeal shock wave lithotripsy

Objectives This study aims to evaluate the attenuation of renal calculi measured by Hounsfield unit (HU) by noncontrast spiral computerized tomography (NCSCT) as a predictor of calculus fragmentation by extracorporeal shock wave lithotripsy (SWL). Background The outcome of extracorporeal SWL is measured in terms of stone fragmentation and clearance. Some authors have suggested that HU of renal calculi by NCSCT may predict stone-free rates after extracorporeal SWL. Patients and methods This prospective nonrandomized open study included 100 patients with renal stone up to 20 mm in size. Stone attenuation was measured by HU on NCSCT. Patients were grouped according to stone attenuation as group (1), less than 500 HU, (2), 500-1000 HU, and (3), greater than 1000 HU. Patients were treated subsequently with extracorporeal SWL. The outcome was categorized as stone free, clinically insignificant stone fragments, and residual fragments more than 3 mm. Results The rate of stone fragmentation was 100% (41 of 41 cases) in group 1, 95.7% (44 of 46) in group 2, and 0% (0 of 13) in group 3. A statistically significant association was found between SWL treatment outcome and stone density. When we correlated the absolute stone HU measured with the number of shock waves required for complete fragmentation, we found that the mean number of shock waves was 248 122 in group 1, 334 826 in group 2, and 726 077 in group 3 ( P Conclusion Stone attenuation measured by HU by NCSCT is a predictor of outcome of SWL and suspected number of shock waves required for fragmentation.

Report on research of calculus fragmentation by HIFU-induced cavitation in Tsinghua University: 2. Thermal effects

Thermal effects in the research of breaking kidney stones using HIFU-induced cavitation were studied. Damages to the phantom could be observed after an acting period of HIFU. It was shown that temperature rise is much greater in phantom than in water. Greatest changes occur near the focal region of HIFU transducer. Distinct temperature changes can be observed with input of continuous signals, while modest changes appear with input of pulsed signals. The fact that pulsed signals generate less damage, indicate the favourable acting patterns of HIFU. More tests are being done at the moment.

Report on research of calculus fragmentation by HIFU-induced cavitation in Tsinghua University: 1. Effects of tissue-mimicking phantom

Study of the acoustic attenuation through human tissues was carried out, in order to accurately evaluate the damaging power of the generated cavitation cloud. Tissue phantom was made, with acoustic properties (acoustic speed and acoustic attenuation factor) similar to human tissues. Preliminary results show that, with the increase of intensity and acting time of the HIFU acoustic waves, the depths of the craters increase rapidly, while the radii of the craters increase mildly. Mass loss of the artificial stones in phantom is less than in water (about 50%), indicating considerable energy dissipation in tissues.

Endoscopic‐Assisted Electrohydraulic Shockwave Lithotripsy in Standing Sedated Horses

To report use of transendoscopic electrohydraulic shockwave lithotripsy for fragmentation of urinary calculi in horses. Case series. Male horses (n = 21). Fragmentation of cystic calculi (median, 6 cm diameter; range, 4-11 cm diameter) was achieved by transurethral endoscopy in standing sedated horses using an electrohydraulic shockwave fiber introduced through the biopsy channel of an endoscope. The fiber was advanced until it contacted the calculus. Repeated activation of the fiber was used to disrupt the calculus into fragments <1 cm diameter. Visibility within the bladder was maintained by repeated lavage with saline solution. Complete calculus removal was achieved in 20 horses (95%) with mean total surgical time of 168.6 minutes (range, 45-450). In the 20 horses with single calculi, 1-6 sessions were required to completely fragment the calculus. Except for 1 horse, in which perineal urethrotomy was eventually performed for complete fragment removal, fragments calculi were excreted via the urethra. Postoperative complications included hematuria because of severe mucosal erosion (n = 2), dysuria because of a trapped urethral fragment (2), small amount of urinary debris (1). One horse was euthanatized because of bladder rupture. Complete clearance of calculi and urinary debris was confirmed endoscopically 20 (3-45) days after the last session. Telephone follow-up (mean, 18.8 months; range, 7-24 months) revealed that horses had returned to previous activity levels without recurrence of clinical signs. Transendoscopic electrohydraulic lithotripsy appears to be an effective method for fragmentation of low-density calcium carbonate cystic calculi in male horses.

Abdominal fat distribution on computed tomography predicts ureteric calculus fragmentation by shock wave lithotripsy

To assess the effects of abdominal fat on shock wave lithotripsy (SWL). We used pre-SWL unenhanced computed tomography (CT) to evaluate the impact of abdominal fat distribution and calculus characteristics on the outcome of SWL. One hundred and eighty-five patients with a solitary ureteric calculus treated with SWL were retrospectively reviewed. Each patient underwent unenhanced CT within 1 month before SWL treatment. Treatment outcomes were evaluated 1 month later. Unenhanced CT parameters, including calculus surface area, Hounsfield unit (HU) density, abdominal fat area and skin to calculus distance (SSD) were analysed. One hundred and twenty-eight of the 185 patients were found to be calculus-free following treatment. HU density, total fat area, visceral fat area and SSD were identified as significant variables on multivariate logistic regression analysis. The receiver-operating characteristic analyses showed that total fat area, para/perirenal fat area and visceral fat area were sensitive predictors of SWL outcomes. This study revealed that higher quantities of abdominal fat, especially visceral fat, are associated with a lower calculus-free rate following SWL treatment. Unenhanced CT is a convenient technique for diagnosing the presence of a calculus, assessing the intra-abdominal fat distribution and thereby helping to predict the outcome of SWL. • Unenhanced CT is now widely used to assess ureteric calculi. • The same CT protocol can provide measurements of abdominal fat distribution. • Ureteric calculi are usually treated by shock wave lithotripsy (SWL). • Greater intra-abdominal fat stores are generally associated with poorer SWL results.