Paclitaxel-coated stents to prevent hyperplastic proliferation of ureteral tissue: from in vitro to in vivo.

Ureteric stents have become an indispensable tool in the armamentarium of every urologist. However, they carry their own morbidity resulting mostly from infectious or abacterial fouling and biofilm formation, and/or urothelial hyperplastic reaction. All of these may interact and lead to clinical complications. Many different stent designs and coatings have been proposed. In this study, we focused on the effect of paclitaxel-coated stents on hyperplastic proliferation of ureteral tissue, using as example anastomotic strictures after ureteroureterostomy in a rat model. Human urothelial cells (SV-HUC-1) were used to determine paclitaxel dosages in vitro. Polyurethane stents were coated with a paclitaxel containing biodegradable polymer and studied in a ureteroureterostomy rat model. 48 male 9-week-old Sprague-Dawley rats underwent either sham surgery (n = 16) or ureteroureterostomy with sutured anastomosis, and consecutive stenting with either a paclitaxel-coated or an uncoated stent (16 per group), respectively. The animals received daily intraperitoneal injections of 5-bromo-2-deoxyuridine (20 mg/ml, 100 mg/kg body weight) during the first eight postoperative days, and were sacrificed on day 28. Healing of the ureteral anastomosis and proliferation of urothelial cells was examined histologically and immunohistochemically. In vitro, a concentration of 10 ng/mm2 paclitaxel can be considered as non-toxic, while still exerting an anti-proliferative effect on urothelial cells. Histologically, typical wound healing processes were seen at the site of the ureteral anastomosis in vivo. Proliferation of urothelial cells was significantly lower in animals with paclitaxel-coated stents compared to those with uncoated stents (LI 41.27 vs. 51.58, p < 0.001). Our results indicate that stenting of ureteral anastomoses with paclitaxel-coated stents can reduce hyperplastic proliferation of ureteral tissue. Paclitaxel-coated stents thus might be able to prevent not only scar-induced postoperative stenosis after reconstructive surgery, but also hyperplastic urothelial reaction in non-anastomotic stent patients as part of their inflammatory response to the foreign material.

Benign prostate hyperplasia and nutrition.

BACKGROUND: and aims: Benign Prostatic hyperplasia (BPH) is an important public health problem. Roughly half of all men will suffer from BPH related symptoms later in life. The prostate gland, a hormone dependent part of the male reproductive system, is susceptible to internal and external disruptions of regulatory systems. We attempt in this paper to collect available evidence on influence of lifestyle modifications, and naturally occurring substances, plants, micronutrients and supplements on BPH symptoms. METHODS: Systematic review was performed within the MEDLINE database and Cochrane Library Central Search using a combination of Medical Subject Headings (MeSH) and keywords. RESULTS: Moderate exercise and the type and amount of protein intake have a considerable influence on BPH symptoms. The intake of zinc and vitamin D also positively influence BPH symptoms, and so do certain supplements, such as saw palmetto, cemilton and pygeum extracts. CONCLUSIONS: Lifestyle changes, diet modification and certain nutritional supplements can favorably influence BPH symptoms.

Vision for the future on urolithiasis: research, management, education and training-some personal views.

The field of urolithiasis has undergone many rapid changes in the last 3 decades. In this article, three eminent experts in various fields of urolithiasis research describe their respective visions for the future in stone research, stone treatment and surgical training. Many stone researchers have seen and regretted that there has not been a real breakthrough for decades now. Exceptions are the application of citrate prophylaxis and the abandonment of calcium-avoiding diet in stone formers. Certain areas of stone research have been exhausted and the body of literature available should suffice as background knowledge in those. Yet, to find meaningful mechanisms of clinically applicable stone prevention, the limited funds which are currently available should be used to research priority areas, of which crystal-cell interaction is envisioned by one of the present authors as being a crucial direction in future stone research. In the opinion of the second author, surgical stone treatment is very much technology-driven. This applies to the evolution of existing technologies and instruments. In addition, robotics, IT and communication software, and artificial intelligence are promising and are steadily making a meaningful impact in medicine in general, and endourology in particular. Finally, the third author believes that despite the exciting advances in technology, the role of the surgeon can never be replaced. The idea of a fully automated, artificially thinking and robotically performing system treating patients medically and surgically will not appeal to urologists or patients but may at least be a partial reality. His vision therefore is that surgical training will have to take on a new dimension, away from the patient and towards virtual reality, until the skill set is acceptably developed.

Ureteral stent encrustation. Pathophysiology.

Ureteral stents are the most commonly used urological implants. They are used for temporary as well as for long-term ureteral stenting. Amongst others, complications of ureteral stenting are encrustation and cellular adherence which, in turn, promotes urinary tract infection and can induce impaired healing in case of ureteral damage. Biofilm formation on urological implants leads to the protection of persisting bacteria from local defense mechanisms, thereby rendering persistent urinary tract infections more common. It seems clear that antibiotics cannot penetrate into biofilms adequately. Also, bacteria persist in biofilms in a state of reduced metabolism which further reduces antibiotic efficacy. Furthermore, bacteria develop resistance more quickly in biofilms. This paper tries to give an overview of the complex pathophysiological mechanisms that underlie stent encrustation as far as we know to date.

A comprehensive update on urinary tract lithiasis management.

In the past decade, the field of urology has been one of the most rapidly progressing in applied technological advancements at the level of both medical diagnostics and treatment. The introduction of modern robotic laparoscopy has changed the face of minimally invasive surgery. For endourology specialists, stone surgery continues to be in the forefront of daily practice and innovations and new technologies are constantly being developed, aiming towards ever higher stone free rates and earlier recovery for the patient. But, is there a price? Indeed, in addition to advances in conservative treatment and prevention, modern endourology and stone disease management in particular enjoys a large variety of sophisticated new equipment and disposables, used either alone or in combination, developed from various companies at considerable cost. It is more than often that even expert professionals are not totally familiar with the whole range of treatment options and devices that are available in the market, as they commonly bear different names despite being used for the same purpose. Furthermore, a question of integrity might arise when using newly developed equipment directly in the operating theatre, with respect to the efficacy of the device as well as the learning curve required by the operator. In this review, we shall outline the latest advances in interventional lithotripsy technology and also demonstrate the most effective ways to use each particular modality efficiently and safely, with respect to the latest published guidelines and evidence-based recommendations.

Stent encrustation in feline and human artificial urine: does the low molecular weight composition account for the difference?

Anecdotal evidence suggests that the rate of encrustation on JJ stents placed in domesticated cats appears to be decreased as compared to humans. Our study tests the hypothesis that this may be due to specific differences in the chemical composition of human and feline urine. Artificial human and feline urine solutions were used in an in vitro encrustation model where an 80 % stent encrustation could be expected after 7 weeks of incubation. Scanning electron microscopy (SEM) was used to analyse crystal morphology. Energy dispersive X-ray spectrometry (EDS) was used to assess composition weight. The percentage of surface coverage of encrustation on the respective stents was quantified using image J Java plug-in software. No significant difference was observed between both solutions with regard to quality and quantity of stent encrustation. Crystals were formed in both solutions as a mixture of Ca-dihydrate and Ca-monohydrate. The study shows that there is no significant difference in the rate of encrustations on JJ stents incubated in artificial feline or human urine. This suggests that a possible difference in stent encrustation between cats and humans is due to factors other than the inorganic biochemical composition of the urines alone. Keeping in mind a true species difference, analysis of urinary macromolecules and proteins will be the logical next step.

Factors predicting success of emergency extracorporeal shockwave lithotripsy (eESWL) in ureteric calculi--a single centre experience from the United Kingdom (UK).

Few studies show that "emergency extracorporeal shockwave lithotripsy (eESWL)" reduces the incidence of ureteroscopy in patients with ureteric calculi. We assess success of eESWL and look to study and identify factors which predict successful outcome. We retrospectively studied patients presenting with their first episode of ureteric colic undergoing eESWL (within 72 h of presentation) over a 5-year period. Patient's age, gender, stone size and location, time between presentation and ESWL, number of shock waves and ESWL sessions, and Hounsfield units (HU) were recorded. 97 patients (mean age 40 years; 76 males, 21 females) were included. 71 patients were stone free after eESWL (73.2 %) (group 1) and 26 patients failed treatment and proceeded to ureteroscopy (group 2). The two groups were well matched for age and gender. Mean stone size in group 1 and 2 was 6.4 mm and 7.7 mm, respectively, (p = 0.00141). Stone location was 34, 21, and 16 in upper, middle and lower ureter in group 1 compared to 11, 5, and 10 in group 2, respectively. Mean HU in group 1 was 480 and 612 in group 2 (p value 0.0036). In group 2, significantly, more patients received treatment after 24 h compared with group 1 (38 vs 22.5 %). The number of shock waves, maximal intensity, and ESWL sessions were not significantly different in the two groups. No complications were noted. eESWL is safe and effective in patients with ureteric colic. Stone size and Hounsfield units are important factors in predicting success. Early treatment (≤24 h) minimizes stone impaction and increases the success rate of ESWL.

Update on intracorporeal laser lithotripsy.

Nowadays, rigid and flexible ureteroscopy is a precise, minimal invasive surgery that can assess the entire collecting system in order to treat a stone with intracorporeal lithotripsy. The implication of laser technology has revolutionized the intracorporeal lithotripsy. Currently, laser lithotripsy is advancing in two different directions: improvements of the existing Ho:YAG laser platform and the development of novel laser systems. Herein, we review the current literature upon intracorporeal lithotripsy.

[Freiburg index of patient satisfaction: interdisciplinary validation of a new psychometric questionnaire to describe treatment-related patient satisfaction]. / Freiburger Index für Patientenzufriedenheit: Interdisziplinäre Validierung eines psychometrischen Instrumentes zur Erfassung behandlungsbezogener Patientenzufriedenheit.

BACKGROUND: The recently introduced Freiburg index of patient satisfaction (FIPS) is a new questionnaire to assess treatment-related patient satisfaction after surgery and interventional procedures. The questionnaire had first been tested psychometrically in a mixed population of urology patients. The current study describes the results of an interdisciplinary validation. In addition, an English version is presented. METHODS: The questionnaire was used in two cohorts of cardiology (n = 120) and surgical (n = 127) patients. The evaluation included a comprehensive methodological and statistical evaluation including validation in comparison to the ZUF-8 questionnaire. RESULTS: The psychometric evaluation showed good results. The analyzed samples showed no missing values or ceiling effects. Furthermore, a high reliability (Cronbach's alpha 0.82), unidimensionality, sufficient distribution of values and validity (high correlation to the ZUF-8, r = 0.65, p < 0.001) of the questionnaire could be confirmed. CONCLUSIONS: The FIPS constitutes an interdisciplinary validated questionnaire to evaluate treatment-related patient satisfaction which can be used to objectify and compare results from clinical studies and quality in patient care. Colleagues of English-speaking countries are invited to participate in the validation of the hereby presented English version.

The Barts 'flank-free' modified supine position for percutaneous nephrolithotomy.

BACKGROUND: The last decade has seen the emergence of a variety of supine positions for carrying out percutaneous nephrolithotomy (PCNL). These positions all differ with regard to ease of puncture under image guidance, operative field availability, ability to make and dilate multiple tracts and ease of combining retrograde intrarenal surgery (RIRS). As all of these positions have their limitations regarding the important parameters mentioned above, there is a need for a supine position which addresses some of the difficulties. METHODS: We describe and illustrate our flank-free modified supine position, which we believe addresses a number of the issues. RESULTS: Our position allows easy percutaneous access under fluoroscopy (torso only tilted to around 15°), space for placing (flank free of support) and dilating multiple tracts (kidney lies in a fairly neutral position and hence less mobile), a fairly horizontal tract allowing low intrarenal pressures and easy washout of fragments as well as allowing RIRS in a position of relative familiarity. The lesser torso rotation compared with the Valdivia, Galdakao modified and the Barts modified Valdivia positions also means it is more comfortable for patients. CONCLUSIONS: Our results are encouraging and easily comparable with published series on prone position, Valdivia, complete supine and the Barts modified Valdivia positions. We would like to highlight the Barts 'flank-free' modified supine position as one of the standard positions for carrying out supine PCNL.

The new digital flexible ureteroscopes: 'size does matter'--increased ureteric access sheath use!

OBJECTIVES: To evaluate whether the use of sheaths to access the ureter has increased after the introduction of new digital ureterorenoscopes in patients undergoing flexible ureteroscopy. METHODS: 140 patients with kidney stones were randomised to be scoped with either an old-generation fibre-optic flexible ureteroscope (DUR-8, Elite, ACMI; distal tip diameter = 6.75 Fr) or a new-generation digital LCD flexible ureteroscope (Invisio D-URD flexible ureteroscope; distal tip diameter = 8.7 Fr). We recorded the necessity to use a sheath to access the ureter, sheath-related and postoperative complications, and whether or not a JJ stent was left behind. RESULTS: 157 (80 fibre-optic and 77 digital) ureterorenoscopies were performed. Ureteral access sheaths were used significantly more frequently with digital scopes (p = 0.00174). Two patients in the digital scope group had a small distal ureteric perforation from the introducer sheath compared with none in the fibre-optic scope group. CONCLUSIONS: A statistically significant increase in sheath use was observed in the new-generation digital flexible ureteroscopy group. Despite the improvement in image quality, better durability and improved stone clearance, there are some potential drawbacks of these scopes. The increased distal tip diameter can result in increased use of ureteric access sheaths and this may increase morbidity and expense.

Use of a virtual reality simulator to improve percutaneous renal access skills: a prospective study in urology trainees.

OBJECTIVES: This study aims to assess the impact of a virtual reality trainer in improving percutaneous renal access skills of urological trainees. METHODS: A total of 36 urology trainees participated in this prospective study. Initially, they were taken through the exercise of gaining access to the lower pole calyceal system and introducing a guidewire down the ureter. Trainees' performance was then assessed by virtual reality-derived parameters of the simulator at baseline and after 2 h of training. RESULTS: Participants who underwent training with the simulator demonstrated significant improvement in several parameters compared to their baseline performance. There was a statistically significant correlation between total time to perform the procedure and time of radiation exposure, radiation dose and correct calyx puncture (p < 0.01). Trainees needed a mean of 15.8 min from skin puncture to correct guidewire placement into the pelvicalyceal system before and 6.49 min following training. CONCLUSIONS: We found percutaneous renal access skills of trainees improve significantly on a number of parameters as a result of training on the PERC Mentor TM VR simulator. Such simulated training has the potential to decrease the risks and complications associated with the early stages of the learning curve when training for percutaneous renal access in patients.

Use of a segmental thermoexpandable metal alloy stent in the management of malignant ureteric obstruction: a single centre experience in the UK.

INTRODUCTION: The Memokath 051™ is a semipermanent inert metal alloy ureteric stent which can bridge strictures and, compared to double J stents, causes less bladder irritation and pain, is more resistant to external compression forces and may be more effective in patients with malignant ureteric obstruction. We present our experience with this novel stent in such cases. METHODS: All suitable patients referred to us with malignancy-associated ureteric strictures over a 4-year period had ureteric Memokath 051™ stents inserted. Data on aetiology and position of the strictures as well as length of the Memokath stents used and their efficacy and complications were recorded prospectively. RESULTS: 42 ureteric Memokath 051™ stents were inserted in 37 patients (mean age 64 years). 40.5% of strictures were related to gynaecological cancer, 21% to bowel cancer, 14% were post radiation, 14% occurred in prostate cancer patients and 9.5% were found in other cancers. The mean follow-up was 22 months (range 5-60 months). The main complications were stent migrations in 5, urinary tract infections in 3 and blockage of stent due to progressive transitional cell carcinoma of the ureter in 2 cases. CONCLUSION: Memokath 051™ ureteric stents are safe, effective and durable in the long-term treatment of malignant strictures.

Percutaneous nephrolithotomy for removal of a calcified intra-renal artillery shell fragment.

Residual metallic fragments after intra-abdominal penetrating injuries due to fragments of artillery shells are generally inert, although they may rarely re-activate. The authors present a case where such a fragment presented as a renal stone 17 years after injury. The literature was reviewed and the initial difficulties with the radiological diagnosis, as well as treatment approaches and post-operative findings are discussed in the light of existing reports. An additional challenge arose as the authors working in a tertiary endourology centre attempted to remain as minimally invasive as possible, but were limited by the very nature of the foreign body.

Treating bladder-outflow obstruction with thermo-expandable prostate metal stents.

Bladder-outflow obstruction is a common age-related clinical entity due to a variety of benign and malignant diseases of the prostate. Surgical treatment is not suitable for high-risk elderly patients who seek minimally invasive management. We present a prostatic thermo-expandable metal stent for treating bladder-outflow obstruction. In this review, we include the design characteristics of this novel device, the performance assessment in comparison with alternative devices, the limitations, our personal clinical experience, as well as a long-term perspective. According to our experience among 127 patients (who underwent insertion of 192 stents) after 1, 2 and 3 years, 82, 61 and 47% of the original stents were functional without apparent complications, respectively. The mean single stent indwelling time was 1 year, with a maximum of 4 years. In 41% of patients, the stent needed to be removed and/or exchanged owing to stent encrustation (15%), migration (10%), penile pain (6%), bladder-outflow obstruction symptoms (5%), urinary incontinence (<3%), tissue granulation (<3%), recurrent urinary tract infections (<3%) or urethral stricture (<3%). The thermo-expandable prostatic stent seems to be an effective minimally invasive treatment of bladder-outflow obstruction, especially in high-risk patients.

Pain in extracorporeal shock wave lithotripsy.

Pain tolerance has long been identified as a factor influencing successful treatment of renal calculi by shock wave lithotripsy (SWL). We aimed to clarify which factors directly influence pain tolerance to predict which patients are likely to undergo successful treatment. We analysed retrospectively 179 patients who received their first SWL for a solitary kidney stone. All patients were on a non-opioid analgesia protocol and were treated on an outpatient basis. The target was to deliver 4,000 shock waves at an energy level of 4. In total, 53% of patients could tolerate the targeted shock wave number and energy and were retrospectively allocated into group A. Those who required a reduction in either energy levels or shock wave number were allocated in group B. Multivariate and univariate analysis showed that female patients, who are young with thin body habitus, have lower pain tolerance to SWL.