International Alliance of Urolithiasis (IAU) guideline on staghorn calculi management.

BACKGROUND: The stone burden based management strategy reported in the guidelines published by different associations is well known for a long time. Staghorn calculi, representing the largest burden and most complex stones, is one of the most challenging cases to practicing urologists in clinical practice. The International Alliance of Urolithiasis (IAU) has released a series of guidelines on the management of urolithiasis. PURPOSE: To develop a series of recommendations for the contemporary management management of staghorn calculi and to provide a clinical framework for urologists treating patients with these complex stones. METHODS: A comprehensive literature search for articles published in English between 01/01/1976 and 31/12/2022 in the PubMed, OVID, Embase and Medline database is performed. A series of recommendations are developed and individually graded following the review of literature and panel discussion. RESULTS: The definition, pathogenesis, pathophysiology, preoperative evaluation, intraoperative treatment strategies and procedural advice, early postoperative management, follow up and prevention of stone recurrence are summarized in the present document. CONCLUSION: A series of recommendations regarding the management of staghorn calculi, along with related commentary and supporting documentation offered in the present guideline is intended to provide a clinical framework for the practicing urologists in the management of staghorn calculi.

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

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

Percutaneous nephrolithotomy - the puncture.

OBJECTIVE: To determine what importance is given to the puncture and assistive technologies in percutaneous nephrolithotomy (PNL) in the current urological literature. METHODS: PubMed was searched for English publications and reviews for the keywords: 'percutaneous nephrolithotomy', 'percutaneous nephrostomy', 'puncture'. The search was limited to the last 5 years, January 2016 until February 2021. Based on 183 abstracts, 121 publications were selected, read, and reviewed. References, older or seminal papers were read and cited if they contributed to a better understanding. A total of 198 references form the basis of this narrative review. RESULTS: The puncture is frequently referred to as the most crucial part of PNL. In contrast, the influence of the puncture on the failure rate of PNL and the specific puncture-related complications seems to be low in the single-digit percentage range. However, there are no universally accepted definitions and standards measuring the quality of puncture. Consequently, the impact of the puncture on general PNL complications, on stone scores predicting success rates and on learning curves evaluating surgeons' performance have not been systematically studied. Assistive technologies rely on fluoroscopy and ultrasonography, the latter of which is becoming the preferred imaging modality for monitoring the entire procedure. Needle bending, a problem relevant to all puncture techniques, is not addressed in the urological literature. CONCLUSIONS: The importance attached to puncture in PNL in the current urological literature is subjectively high but objectively low. Some basics of puncture are not well understood in urology. Disciplines other than urology are more actively involved in the development of puncture techniques.

The economics of stone disease.

The rising prevalence of kidney stone disease is associated with significant costs to healthcare systems worldwide. This is in part due to direct procedural and medical management costs, as well as indirect costs to health systems, patients, and families. A number of manuscripts evaulating the economics of stone disease have been published since the 2008s International Consultation on Stone Disease. These highlight costs associated with stone disease, including acute management, surgical management, and medical management. This work hopes to highlight optimization in care by reducing inefficient treatments and maximizing cost-efficient preventative strategies.

Positioning for percutaneous nephrolithotomy.

PURPOSE OF THE REVIEW: To highlight the progressive evolution of the issue of patient positioning for percutaneous nephrolithotomy (PNL), explain the history of the prone and supine positions, report respective advantages and drawbacks, critically interpret the past and current literature supporting such arguments, identify the best candidates for each position, and reflect on the future evolution of the two approaches. RECENT FINDINGS: Positioning for PNL has become a matter of debate during the last decade. The traditional prone PNL position - most widely performed with good success and few complications, and exhibiting essentially no limits except for the treatment of pelvic kidneys - is nowadays flanked mainly by the supine and supine-modified positions, equally effective and probably safer from an anesthesiological point of view. Of course, both approaches have a number of advantages and drawbacks, accurately reported and critically sieved. SUMMARY: The current challenge for endourologists is to be able to perform PNL in both prone and supine positions to perfectly tailor the procedure on any patient with any stone burden, including increasingly challenging cases and medically high-risk patients, according to the patient's best interest. Intensive training and experience is especially needed for supine PNL, still less popular and underperformed worldwide. VIDEO ABSTRACT: http://links.lww.com/COU/A8.

Extracorporeal shock wave lithotripsy: An opinion on its future.

The development of miniaturized nephroscopes which allow one-stage stone clearance with minimal morbidity has brought the role of shock wave lithotripsy (SWL) in stone management into question. Design innovations in SWL machines over the last decade have attempted to address this problem. We reviewed the recent literature on SWL using a MEDLINE/PUBMED research. For commenting on the future of SWL, we took the subjective opinion of two senior urologists, one mid-level expert, and an upcoming junior fellow. There have been a number of recent changes in lithotripter design and techniques. This includes the use of multiple focus machines and improved coupling designs. Additional changes involve better localization real-time monitoring. The main goal of stone treatment today seems to be to get rid of the stone in one session rather than being treated multiple times non-invasively. Stone treatment in the future will be individualized by genetic screening of stone formers, using improved SWL devices for small stones only. However, there is still no consensus about the design of the ideal lithotripter. Innovative concepts such as emergency SWL for ureteric stones may be implemented in clinical routine.

The past, present and future of minimally invasive therapy in urology: a review and speculative outlook.

INTRODUCTION: Twenty-five years of SMIT represents an important date. In this article we want to elaborate the development of minimally invasive surgery in urology during the last three decades and try to look 25 years ahead. MATERIAL AND METHODS: As classical scenarios to demonstrate the changes which have revolutionized surgical treatment in urology, we have selected the management of urolithiasis, renal tumour, and localized prostate cancer. This was based on personal experience and a review of the recent literature on MIS in Urology on a MEDLINE/PUBMED research. For the outlook to the future, we have taken the expertise of two senior urologists, middle-aged experts, and upcoming junior fellows, respectively. RESULTS: Management of urolithiasis has been revolutionized with the introduction of non-invasive extracorporeal shock wave lithotripsy (ESWL) and minimally invasive endourology in the mid-eighties of the last century obviating open surgery. This trend has been continued with perfection and miniaturization of endourologic armamentarium rather than significantly improving ESWL. The main goal is now to get rid of the stone in one session rather in multiple non-invasive treatment sessions. Stone treatment 25 years from today will be individualized by genetic screening of stone formers, using improved ESWL-devices for small stones and transuretereal or percutaneous stone retrieval for larger and multiple stones. Management of renal tumours has also changed significantly over the last 25 years. In 1988, open radical nephrectomy was the only therapeutic option for renal masses. Nowadays, tumour size determines the choice of treatment. Tumours >4 cm are usually treated by laparoscopic nephrectomy, smaller tumours, however, can be treated either by open, laparoscopic or robot-assisted partial nephrectomy. For patients with high co-morbidity focal tumour ablation or even active surveillance represents a viable option. In 25 years, imaging of tumours will further support early diagnosis, but will also be able to determine the pathohistological pattern of the tumour to decide whether the patient requires removal, ablation or active surveillance. Management of localized prostate cancer underwent significant changes as well. 25 years ago open retropubic nerve-sparing radical prostatectomy was introduced as the optimal option for effective treatment of the cancer providing minimal side-effects. Basically, the same operation is performed today, but with robot-assisted laparoscopic techniques providing 7-DOF instruments, 3D-vision and tenfold magnification and enabling the surgeon to work in a sitting position at the console. In 25 years, prostate cancer may be managed in most cases by focal therapy and/or genetically targeting therapy. Only a few patients may still require robot-assisted removal of the entire gland. DISCUSSION: There has been a dramatic change in the management of the most frequent urologic diseases almost completely replacing open surgery by minimally invasive techniques. This was promoted by technical realisation of physical principles (shock waves, optical resolution, master-slave system) used outside of medicine. The future of medicine may lie in translational approaches individualizing the management based on genetic information and focalizing the treatment by further improvement of imaging technology.

Percutaneous nephrolithotomy and chronic kidney disease: results from the CROES PCNL Global Study.

PURPOSE: We compared the characteristics and outcomes of patients treated with percutaneous nephrolithotomy in the CROES (Clinical Research Office of the Endourological Society) Global Study according to preoperative renal function. MATERIALS AND METHODS: Prospective data on consecutive patients treated with percutaneous nephrolithotomy in a 1-year period were collected from 96 participating centers. The glomerular filtration rate was estimated using the Modification of Diet in Renal Disease formula based on preoperative serum creatinine measurement. Patients were divided into 3 groups by glomerular filtration rate, including chronic kidney disease stages 0/I/II-greater than 60, stage III-30 to 59 and stages IV/V-less than 30 ml/minute/1.73 m(2). Patient characteristics, operative characteristics, outcomes and morbidity were assessed. RESULTS: Estimated glomerular filtration rate data were available on 5,644 patients, including 4,436 with chronic kidney disease stages 0/I/II, 994 with stage III and 214 with stages IV/V. A clinically significant minority of patients with nephrolithiasis presented with severe chronic kidney disease. A greater number of patients with stages IV/V previously underwent percutaneous nephrolithotomy, ureteroscopy or nephrostomy and had positive urine cultures than less severely affected patients, consistent with the higher incidence of staghorn stones in these patients. Patients with chronic kidney disease stages IV/V had statistically significantly worse postoperative outcomes than those in the other chronic kidney disease groups. CONCLUSIONS: Poor renal function negatively impacts the post-percutaneous nephrolithotomy outcome. By more aggressive removal of kidney stones, particularly staghorn stones, at first presentation and more vigilantly attempting to prevent recurrence through infection control, pharmacological or other interventions, the progression of chronic kidney disease due to nephrolithiasis may be mitigated.

Clinical staging error in prostate cancer: localization and relevance of undetected tumour areas.

OBJECTIVE: To describe the localization and to assess the clinical implications of areas of undetected prostate cancer in radical prostatectomy (RP) specimens, focusing on patients with unilaterally negative preoperative biopsy cores. PATIENTS AND METHODS: The study included 149 of 559 consecutive patients (26.7%) who had RP for prostate cancer. Unilateral prostate cancer was diagnosed from prostate biopsies, taken by several physicians, but > or = pT2c disease was present in the RP specimen. The prostate was dissected by standardized transversal cuts and tumour areas were mapped by one genitourinary pathologist. To estimate the tumour size and location, areas of prostate cancer were transferred to a digital grid database representing the prostate by 794 units. RESULTS: The most frequent location of undetected prostate cancer was in the dorsalateral region and in the apex of the prostate. The mean tumour volume of the false-negative lobe was significantly lower than contralaterally (18.9 vs 47.5 units, P < 0.001). In 36 of 149 patients (24.2%), the tumour volume on the negative biopsy side was equal or higher than on the positive biopsy side; in the final RP specimen, 60 patients (40.3%) had capsular involvement on the negative biopsy side. CONCLUSION: Significantly many patients with newly diagnosed prostate cancer remain clinically understaged. The apical and dorsolateral region of the prostate are not adequately represented in current biopsy strategies. Undetected tumour areas are often clinically significant by size and capsular involvement, indicating a direct clinical implication when planning nerve-sparing RP or focal therapy. Our results show a continuing need for optimized and standardized biopsy protocols.

The lymphatic system and its specific growth factor vascular endothelial growth factor C in kidney tissue and in renal cell carcinoma.

OBJECTIVE To determine the role of vascular endothelial growth factor C (VEGF-C) and the quantitative extent of the lymphatic system in renal cell carcinoma (RCC) to analyse a possible correlation with the metastatic spread of cancer cells. PATIENTS AND METHODS In all, 44 patients with clear cell RCC and 12 with papillary or chromophobe RCC were included in an immunohistochemical study. The lymphatic vessel density (LVD) was assessed in the tumour body, the tumour capsule and the tumour-free adherent renal tissue. The expression of VEGF-C was semiquantitatively assessed by the percentage of positive epithelial and cancer cells. Data were analysed for any correlation with the clinicopathological variables. RESULTS The clear and papillary cell RCC contained no lymphatic vessels (0.2, sd 0.8). Chromophobe RCC specimens showed scattered obliterated vessels (0.0-7.7). Several lymphatic vessels were found in the normal renal tissue, mainly associated with blood vessels (2.9, sd 1.9). The highest mean (sd) LVD was in the tumour capsule, of 6.9 (3.4). There was no statistical correlation between the LVD and VEGF-C. In clear cell RCC the expression of VEGF-C was correlated with the size of the tumour (P = 0.042). CONCLUSIONS RCC does not promote the growth of its own lymphatic vessels. The role of a high LVD in the tumour capsule needs to be determined. The VEGF-C staining pattern in normal kidney tissue hints at functions other than lymphangiogenesis.

Lymphangiogenesis occurs in upper tract urothelial carcinoma and correlates with lymphatic tumour dissemination and poor prognosis.

OBJECTIVE: To describe the lymphatic vessel density and to determine the functional and prognostic significance of tumoral lymphatic vessels in upper tract urothelial carcinoma (UTUC). PATIENTS AND METHODS: The study included 65 patients who had a radical nephroureterectomy (RNU) for UTUC between 1997 and 2004. All pathological slides were re-evaluated by one reference pathologist and clinical data were reviewed. Lymphatic endothelial cells (LECs) were stained immunohistochemically using D2-40. The lymphatic vessel density (LVD) was described in representative intratumoral (ITLVD), peritumoral (PTLVD) and non-tumoral (NTLVD) areas. Random samples were selected for double-immunostaining with D2-40 and CD-34 (to distinguish blood and lymphatic vessels) and the proliferation marker Ki-67 to detect lymphangiogenesis. The primary outcome measures were disease-specific survival (DSS) and disease recurrence (urothelial and/or distant). RESULTS: The median (interquartile range) PTLVD was 4.0 (3.0-6.3), and significantly higher than that for ITLVD, of 0.3 (0-1.7) (P < 0.001), and NTLVD, of 3 (2.0-3.7) (P < 0.001). Both a higher ITLVD and PTLVD, the presence of lymphovascular invasion (LVI) (each P < 0.001) and a high tumour grade (P = 0.004) were associated with reduced DSS on univariate analysis. A higher PTLVD (P = 0.028) and the presence of LVI (P = 0.020) independently predicted reduced DSS on multivariate analysis. IT and PT lymphatic vessels showed proliferating LECs in all analysed samples. CONCLUSION: Lymphangiogenesis is present in UTUC, as shown by a significantly increased PTLVD and proliferating LECs. Our findings suggest functional relevance of PT lymphatic vessels during lymphatic tumour spread. PTLVD is a potential novel prognostic factor for DSS in UTUC, and further prospective studies will be needed to determine the effect of its routine evaluation on clinical outcomes of this malignancy.

An alternative continence tube for continent urinary reservoirs: evaluation of surgical technique, pressure and continence study in an ex-vivo model.

OBJECTIVE: Despite the large number of surgical techniques for continent cutaneous diversion described in literature, the creation of a reliable, continent and easily catheterizable continence mechanism remains a complex surgical procedure. AIM: Aim of this study was the evaluation of a new method for a catheterizable continence mechanism using stapled pig intestine. METHODS: Small and large pig intestines were used for construction. A 3 or 6 cm double row stapling system was used. Three variations using small and large intestine segments were constructed. A 3 or 6 cm long stapler line was placed alongside a 12 Fr catheter positioned at the antimesenterial side creating a partially two-luminal segment. Construction time for the tube was measured. The created tube was then embedded into the pouch. Pressure evaluation of the continence mechanism was performed for each variation. Intermittent external manual compression was used to simulate sudden pressure exposure. RESULTS: All variations were 100% continent under filling volumes of up to 700 ml and pressure levels of 58 +/- 6 cm H(2)O for large intestine and 266 ml and 87 +/- 18 cm H(2)O for small intestine, respectively. With further filling above the mentioned capacity suture insufficiency occurred but no tube insufficiency. Construction time for all variations was less than 12 min. CONCLUSION: The described technique is an easy and fast method to construct a continence mechanism using small or large intestine. Our ex vivo experiments have shown sufficient continence situation in an ex-vivo model. Further investigations in an in-vivo model are needed to confirm these results.

Paclitaxel encapsulated in cationic liposomes: a new option for neovascular targeting for the treatment of prostate cancer.

Neovascular targeting is an established approach for the therapy of prostate cancer (PCa). Cationic liposomes have been shown to be absorbed by immature vascular endothelial cells due to negative electric charge of their outer cell membrane. We aimed to evaluate the antitumoural efficacy of paclitaxel encapsulated in cationic liposomes for the treatment of PCa. Tumours were generated by subcutaneous injection of 10(6) MatLu tumour cells into the right hind leg of 21 male Copenhagen rats. After tumour growth, the animals were treated by an i.v. infusion with either 5% glucose (Gl), paclitaxel (Pax), cationic liposomes (CL) or paclitaxel encapsulated in cationic liposomes (EndoTAG-1) on days 12, 14, 16 and 19. Treatment was initiated on day 12 after tumour inoculation at mean tumour volumes of 0.31+/-0.13 mm(3). On the last day of treatment, animals treated with EndoTAG-1 had the significantly lowest tumour volumes with 2.49+/-0.84 cm(3) vs. Pax (5.59+/-0.45 cm(3)) vs. CL (3.87+/-1.25 cm(3)) vs. GL (5.17+/-1.70 cm(3)). The quantification of MVD showed the lowest count for EndoTAG-1-treated tumours (11.78+/-2.68 vessels/mm(2)) followed by Gl (15.64+/-6.68 vessels/mm(3)), Pax (18.22+/-9.50 vessels/mm(3)) and CL (40.9+/-32.8 vessels/mm(3)). The data confirm that neovascular targeting with EndoTAG-1 is a promising new method for the treatment of PCa by reducing the primary tumour mass and demonstrating benefits in the suppression of angiogenesis in comparison with the conventional treatment.

Outcome of sigmoid compared to ileal orthotopic bladder substitution in terms of micturition and defecation parameters in an 8-year long-term follow-up.

INTRODUCTION: Various techniques have been described for orthotopic bladder substitution. Bladder substitution with sigma is rather classed as a useful alternative standby. We report the long-term results of sigmoid neobladder in comparison to ileal neobladder with respect to urodynamic and defecation parameters. PATIENTS AND METHODS: We matched 10 patients with sigmoid neobladder (mean age 62.6 +/- 10.9) and 10 patients with ileal neobladder (mean age 66.4 +/- 10.2). Mean follow-up for sigmoid neobladder was 8.1 +/- 2.1 years and 7.2 +/- 1.9 years for the ileal neobladder. Each patient was evaluated by medical history, the SF-36 questionnaire, physical examination and urodynamics. RESULTS: Bladder capacity differed significantly between both groups (sigmoid neobladder 619 ml, ileal neobladder 422 ml). Pressure showed a slight statistical difference (sigmoid neobladder 15 +/- 3 cm H(2)O, ileal neobladder 18 +/- 4 cm H(2)O). The defecation frequency varied significantly between the two groups (sigmoid neobladder 1.1/day, ileal neobladder 3.1/day, p < 0.0001). The SF-36 questionnaire showed no significant difference. CONCLUSION: Orthotopic bladder substitution with sigmoid segments has shown equivalent results compared to orthotopic ileal bladder substitution. The sigmoid neobladder is a useful alternative to the ileal neobladder.

[Looking back on 50 years of stone treatment]. / Rückblick auf 50 Jahre Steintherapie.

Urolithiasis is an urologist's daily business. This article provides an overview of the developments in the management of urinary stone disease since the 1970s. While conventional KUB X-rays and intravenous pyelography were standard imaging procedures in the past, computed tomography is the first choice today. Conservative treatments such as medical expulsive therapy were established to facilitate ureteral stone passage, but have come into discussion in the past few years. Fifty years ago, open stone surgery was the standard procedure to access renal stones. This has been superseded by minimally-invasive procedures ranging from percutaneous nephrolithotomy (PCNL) to extracorporeal shock-wave lithotripsy (ESWL) and ureteroscopy (URS), which is today's standard for most upper urinary tract stones. It would have been desirable if such enormous efforts and progress had been made in the evaluation of stone pathogenesis and the improvement of preventative measures. Unfortunately, the knowledge on stone formation has hardly improved compared to 1970.

Metastasis is promoted by a bioenergetic switch: new targets for progressive renal cell cancer.

Targeted therapies have demonstrated clinical benefit with limited impact on long-term disease specific survival in the treatment of renal cell cancer (RCC). New opportunities for the treatment of tumors that are resistant or have relapsed, are needed. Increased anaerobic glucose fermentation to lactate (aerobic glycolysis), leading to oxygen- and mitochondria-independent ATP generation is a hallmark of aggressive cancer growth. This metabolic shift results in increased lactate production via cycling through the pentose phosphate pathway (PPP), and plays an important role in tumor immune escape, progression and resistance to immune-, radiation- and chemo-therapy. This study explored the activity and impact of the oxidative and nonoxidative branches of the PPP on RCC to evaluate new therapeutic options. Activity was determined in the oxidative branch by glucose-6-phosphate-dehydrogenase (G6PD) activity, and in the nonoxidative branch by the total transketolase activity and the specific expression of the transketolase-like-1 (TKTL1) protein. Transketolase and G6PD activity were intensely elevated in tumor tissues. Transketolase, but not G6PD activity, was more elevated in metastasizing tumors and TKTL1 protein was significantly overexpressed in progressing tumors (p = 0.03). Lethal tumors, where surrogate parameters such as grading and staging had failed to predict progression, showed intensive TKTL1 protein expression. RCC was found to have activated oxidative and nonoxidative glucose metabolism through the PPP, displaying a bioenergetic shift toward nonoxidative glucose fermentation in progressing tumors. The coexistence of cancer cells with differentially regulated energy supplies provides new insights in carcinogenesis and novel anticancer targets.

Conventional high pressure versus newly developed continuous-flow ureterorenoscope: urodynamic pressure evaluation of the renal pelvis and flow capacity.

PURPOSE: We evaluated the pressure and flow relation of a newly developed continuous-flow ureterorenoscope (URS) in comparison with a common ureterorenoscope in an ex-vivo urinary tract model. MATERIALS AND METHODS: Ureterorenoscopies were performed with the newly developed 10.5F continuous-flow URS with separate inflow and outflow channel and a conventional 10.5F URS with a combined inflow and outflow channel. The ex-vivo model consisted of complete urinary tracts of domestic pigs obtained freshly from the slaughterhouse. Both instruments were used in five urinary tracts, and six ureterorenoscopies were performed in each urinary tract. The pressure in the renal pelvis (RP) was measured during each procedure. Height of the irrigation solution above renal level and flow capacity were also documented. RESULTS: The conventional URS showed a correlation of intrapelvic pressure and the height of the irrigation solution above renal level rising from 20+/-3.7 cm H(2)O at a solution level of 20 cm to a plateau pressure of 40+/-3.3 cm H(2)O with a distinct renal influx at a level of 50 cm. The maximum flow capacity at a solution level of 20 cm was 0.2 mL/min rising to a flow capacity of 0.5 mL/min at 40 cm above renal level. The maximum flow capacity for the continuous-flow URS was about 100 times higher, rising from 20 mL/min at a solution level of 20 cm to 70 mL/min at 40 cm above renal level. The intrapelvic pressure was 15+/-2.1 cm H(2)O at a solution level of 20 cm and did not exceed the physiologic renal pressure of 20 cm H(2)O even if the irrigation solution was at a height of 100 cm above renal level. CONCLUSION: The newly developed continuous-flow URS provides a 100 times higher flow capacity while simultaneously preserving the physiologic pressure in the RP compared with the conventional URS. These characteristics will improve visibility and reduce retrograde stone manipulation, operative time, and complications under clinical conditions.

Transarterial nephrectomy: the current status of experimental and clinical studies.

INTRODUCTION: Open nephrectomy is associated with significant morbidity. For several years, minimally invasive alternatives have been developed such as laparoscopic nephrectomy or transarterial renal ablation. This paper focuses on the different principles of vaso-occlusion and further improvements of the technique such as capillary chemoembolization in experimental as well as clinical studies. MATERIALS AND METHODS: Based on own in vitro studies, the principle of capillary embolization with occlusion of the entire arterial system up to the capillaries by a precipitating corn protein (Ethibloc) has been developed in animal studies (i.e., rat and canine kidney model). The precipitation speed of Ethibloc can be prolonged by 40% glucose per injection. The organ-ablative efficacy was evaluated in models of unilateral hypertension and chemically induced renal tumors (i.e., dimethyl-nitrosamine). Further studies using the model of unilateral transarterial implantation of Yoshida-sarcoma cells compared capillary chemoembolization using Ethibloc/mitomycin C (MMC) versus chemoperfusion and capillary embolization. Before starting clinical trials, the optimal mixture of Ethibloc and MMC was determined in vitro and in vivo. Prior to the vaso-occlusion, the volume of the arterial system of the kidney is determined by perfusion of the kidney with contrast-dye via a blocked balloon-catheter. Then 25% of the determined volume of 40% glucose is pre-injected followed by Ethibloc/MMC being injected with 1-cm(3) syringes. Once the capillary bed and tumor sinusoids are reached, the balloon catheter is emptied by postinjection of 40% glucose. RESULTS: Capillary embolization proved to be significantly superior to a central (i.e., ligation of renal artery) or peripheral type of occlusion resulting in complete coagulation necrosis of the normal rat and canine kidney with reduction of the elevated blood pressure, similar to nephrectomy in the model of renal hypertension. In the model of chemically induced renal tumors, complete necrosis of T2 stages could be achieved in 83% using Ethibloc compared to only 63% with Gelfoam particles, and 17% after ligation. In T3/T4 stages, the response rate was only 60% versus 0% after central and peripheral occlusion. In the highly aggressive Yoshida-sarcoma model, capillary chemoembolization yielded an 80% complete response rate compared to only 75% after capillary embolization and 70% after chemoperfusion. The optimal mixture of Ethibloc and MMC ranged between 1 and 2 mg of MMC to 1 cm(3) of Ethibloc, therefore for clinical trials 10 mg MMC was added to the 7.5 cm(3) syringe of Ethibloc. Clinical studies included 68 preoperatively as well as 62 palliatively embolized patients with renal cell carcinoma. The procedure was relatively well tolerated and usually associated with a mild postembolization syndrome. After an interval of up to 28 days, complete necrosis of the renal tumor could be achieved in tumors up to 9 cm in diameter. Hematuria ceased in all cases, and in selected cases long-lasting responses of very large tumors (i.e., vena cava involvement) could be achieved. DISCUSSION: Capillary chemoembolization represents an effective concept for ablation of malignant renal tumors. It offers control of tumor growth in case of temporary inoperability as well as cessation of hematuria in a palliative situation. Because of the local ablative efficiency, it may still represent a minimally invasive option in advanced stages of renal carcinoma (i.e., in combination with immunochemotherapy or targeted therapy).

Systematic evaluation of a recently introduced 2-microm continuous-wave thulium laser for vaporesection of the prostate.

BACKGROUND AND PURPOSE: A novel 2-microm continuous wave (CW) thulium laser device for interventional treatment of benign prostatic hyperplasia was recently introduced into clinical practice and is postulated to have several advantages over more established laser devices. A systematic ex-vivo evaluation of the thulium laser was undertaken to compare the results to transurethral resection of the prostate (TURP) and the potassium-titanyl-phosphate (KTP) laser as reference standard methods. MATERIALS AND METHODS: The RevoLix CW thulium laser system was evaluated in the well-established model of the isolated blood-perfused porcine kidney to determine its tissue ablation capacity and hemostatic properties at different power settings. Histologic examination of the ablated tissue followed. The results were compared to the reference standards, TURP and 80-W KTP laser. RESULTS: At a power setting of 70 W, the CW thulium laser displays a higher tissue ablation rate, reaching 6.56+/-0.69 g after 10 minutes, compared to the 80 W KTP laser (3.99+/-0.48 g; P<0.05). Only 30 seconds were needed to resect tissue with the same surface area using TURP, resulting in 8.28+/-0.38 g of tissue removal. With a bleeding rate of 0.16+/-0.07 g/min, the CW thulium laser offers hemostatic properties equal to those of the KTP laser (0.21+/-0.07 g/min), and a significantly reduced bleeding rate compared to TURP (20.14+/-2.03 g/min; P<0.05). The corresponding depths of the coagulation zones were 264.7+/-41.3 microm for the CW thulium laser, 666.9+/-64.0 microm for the KTP laser (P<0.05), and 287.1+/-27.5 microm for TURP. CONCLUSION: In this standardized ex-vivo investigation, the 2-microm CW thulium laser offered a higher tissue ablation capacity and similar hemostatic properties as those of the KTP laser, and in comparison to TURP both tissue ablation and the bleeding rate were significantly reduced.