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Transformations of many aspects of surgery have provided a potentially fertile ground for the implementation of surgical simulators in the medical mainstream. The expansion of minimally invasive diagnostic and therapeutic modalities, increasing healthcare demands, fiscal constraints, and sensitivity to medicolegal considerations limit resident instruction and practical experience in the operating room. Furthermore, the need for objective, structured assessments of surgical residents during training and the requirement for physicians to gain and maintain certification demand that innovative solutions be sought. Surgical simulators are poised to deliver broad-based training experiences to trainees of all levels. In urology, simulation has been centered on endourologic procedures, namely ureteroscopy and cystoscopy. In this paper, various models of simulation developed for ureteroscopy and cystoscopy in urology are reviewed, with a brief description of each model, its benefits and disadvantages, and current research surrounding each simulation model.

Ureteropelvic junction obstruction (UPJO) is a well-known pathologic condition with several potential associated urologic complications. The treatment for UPJO has evolved dramatically during the past two decades with the advent of minimally invasive treatment options. This has resulted in shorter hospital stays, reduced postoperative pain, and quicker convalescence compared with the gold standard, open pyeloplasty. Antegrade (percutaneous) endopyelotomy is one of the many minimally invasive treatment options for this disorder. In this article, we review the technical aspects, outcomes, and current role of antegrade endopyelotomy in the treatment of UPJO.

Urethral stents are a minimally invasive therapy used in the treatment of benign prostatic hyperplasia, urethral stricture, or detrusor sphincter dyssynergia. This chapter reviews the different types of urethral stents, indications for their use, and clinical results. Urethral stents may be positioned in the urethra or prostatic urethra and are classified as temporary or permanent. Temporary stents are further subdivided into biodegradable and nonbiodegradable. This form of therapy is particularly useful in patients who are at high anesthetic risk and are unable to undergo surgical procedures considered to be the gold standard, such as transurethral prostatectomy or open urethroplasty for prostatic enlargement and urethral stricture disease. Urethral stents can provide an effective alternative to transurethral and open procedures in many urological disorders that affect the prostate and urethra.

Ureteral stents are commonly used in urolithiasis patients for relief of obstruction or in association with stone treatments such as ureteroscopy and extracorporeal shock wave lithotripsy. There are currently many different bulk materials and coatings available for the manufacture of ureteral stents, however the ideal material has yet to be discovered. All potential biomaterials must undergo rigorous physical and biocompatibility testing before commercialization and use in humans. Despite significant advances in basic science research involving biocompatibility issues and biofilm formation, infection and encrustation remain associated with the use of biomaterials in the urinary tract. There have been many significant advances in the design of ureteral stents in recent years and these will be highlighted along with a discussion of future aspects of biomaterials and use of stents in association with urolithiasis.

Ureteral stents are commonly used in urology today, but the biofilms that form on them within hours of placement may harbor bacteria that can result in infection or encrustation. Triclosan is an antimicrobial commonly used in consumer and medical products that inhibits bacterial fatty-acid synthesis. The bactericidal and bacteriostatic effect of a triclosan-eluting ureteral stent was tested against clinical isolates of common bacterial uropathogens in an in-vitro setting.Triclosan eluted from a drug-loaded ureteral stent was suspended in artificial urine with bacterial pathogens (Escherichia coli C1214, Proteus mirabilis 296, Enterococcus faecalis 1131, Klebsiella pneumoniae 280, Staphylococcus aureus Newman, Pseudomonas aeruginosa AK1) to assess growth, virulence-promoter activity, and bacterial adherence to the stent. Generic stents were utilized as controls.Triclosan inhibited the growth of E. faecalis, K. pneumoniae, S. aureus, and P. mirabilis in a dose-dependent manner. Pseudomonas aeruginosa demonstrated significant resistance. Lower concentrations of triclosan downregulated E. coli virulence-factor promoters of outer membrane protein X and p-fimbriae. Triclosan stents had significantly fewer adherent viable bacteria than control stents.Triclosan-eluting ureteral stents inhibit the growth of common bacterial uropathogens and thus may reduce the incidence of urinary-tract infections and, potentially, encrustation. This drug-eluting stent provides both mechanical drainage of the upper urinary tract and local antibiosis.

Lower-pole ureteronephroscopy requires transmission of holmium:YAG energy along a deflected fiber. Current ureteroscopes are capable of high degrees of deflection, which may stress laser fibers beyond safe limits during lower-pole use. We hypothesized that optical fiber and safety measures differ among manufacturers.Small (200-273-microm) and medium-diameter (300-400-microm) Ho:YAG fibers were tested in a straight and 180 degrees bent configuration. Energy transmission was measured by an energy detector. Fiber durability was assessed by firing the laser in sequentially tighter bending diameters. The fibers were bent to 180 degrees with a diameter of 6 cm and run at 200- to 4000-mJ pulse energy to determine the minimum energy required to fracture the fiber. The bending diameter was decreased by 1-cm increments and testing repeated until a bending diameter of 1 cm was reached. The maximum deflection of the ACMI DUR-8E ureteroscope with each fiber in the working channel was recorded. The flow rate through the working channel of the DUR-8E was measured for each fiber.The mean energy transmission differed among fibers (P0.001). The Lumenis SL 200 and the InnovaQuartz 400 were the best small and medium-diameter fibers, respectively, in resisting thermal breakdown (P0.01). The Dornier Lightguide Super 200 fractured repeatedly at a bend diameter of 2 cm and with the lowest energy (200 mJ). The other small fibers fractured only at a bend diameter of 1 cm. The Sharplan 200 and InnovaQuartz Sureflex 273T were the most flexible fibers, the Lumenis SL 365 the least. The flow rate was inversely proportional to four times the power of the diameter of the fiber.Optical performance and safety differ among fibers. Fibers transmit various amounts of energy to their cladding when bent. During lower-pole nephroscopy with the fiber deflected, there is a risk of fiber fracture from thermal breakdown and laser-energy transmission to the endoscope. Some available laser fibers carry a risk of ureteroscope damage.

The need to develop new methods of surgical training combined with advances in computing has led to the development of sophisticated virtual reality surgical simulators. The PERC Mentortrade mark is designed to train the user in percutaneous renal collecting system access puncture. We evaluated and established face, content and construct validation of the simulator in this task.A total of 63 trainees underwent baseline testing on the simulator, consisting of percutaneous renal puncture followed by the introduction of a guidewire into the collecting system. Subjects were then randomized to an intervention arm, in which they underwent 2, 30-minute training sessions on the simulator, and a control arm, in which no further training was given, followed by repeat testing. Performance was assessed using a global rating scale and by virtual reality derived parameters.There were no significant differences between the 2 groups with respect to baseline measures. Subjects who underwent training with the simulator demonstrated significant improvement in objective and subjective parameters compared to their baseline performance and compared to the untrained control group. Spearman rank correlations demonstrated a significant relationship between multiple parameters of the objective and subjective data.Training on the simulator improves virtual reality skills. It may allow trainees to develop the basic skills necessary to perform percutaneous renal collecting system access. Face and content validity were demonstrated and construct validity was supported by establishing convergent validity.

Knowledge of urinary stone composition and structure provides important insights in guiding treatment and preventing recurrence. No current method can successfully provide information relating structure and composition of intact stones. We are developing a tomographic technique that uses measures of coherently scattered diagnostic x-rays to yield stone composition. Coherent-scatter (CS) properties depend on molecular structure and are, therefore, sensitive to material composition. Powdered, amorphous or polycrystalline materials with no significant orientation produce circularly symmetric CS patterns. However, in materials with preferred crystallite orientation, like urinary stones, bright spots in CS patterns are observed. This compromises a composition analysis based on comparing CS measurements from calculi to a library of CS signatures from powdered chemicals. We show that a computed tomographic reconstruction of CS measurements using filtered backprojection (CSCT) effectively eliminates bright spots and yields CS patterns equivalent to powdered materials. This allows for direct comparison with a powdered chemical reference library to establish composition. Validation is achieved through a tomographic CS analysis of an aluminium (Al) rod phantom. Much like calculi, CS patterns from a solid polycrystalline Al rod exhibit diffraction spots, absent in the ring-like Al powder CS pattern. We show that the reconstructed Al CS cross-section is equivalent to its powdered counterpart and results in clearly defined composition images. The potential of CSCT to identify stone composition is demonstrated through images of intact stones deemed chemically pure by infrared spectroscopy. Computed tomographic reconstruction of CS signals allowed the generation of composition maps, showing the distribution of stone components. These images provide strong evidence that current laboratory techniques risk missing critical stone components due to inadequate sampling. This is of particular importance since follow-up treatments are based on these composition analyses. CS analysis can distinguish common stone components and can provide topographic composition maps of intact stones. Such details offer invaluable clinical information regarding stone formation, treatment and follow-up, and thus support the development of CS analysis as a laboratory stone analysis technique.

Infection and encrustation remain major limitations of ureteral stent use and to our knowledge no device has completely overcome these obstacles to date. Triclosan is a biocide currently used in a plethora of consumer and medical products that has recently been loaded into a ureteral stent. Using a rabbit model of UTI we examined the effects of triclosan impregnated stent segments on the growth and survival of Proteus mirabilis, a uropathogen commonly associated with device related UTI and encrustation.A total of 48 male New Zealand White rabbits were instilled transurethrally with 1 x 10(6) P. mirabilis 296. A stent curl from a triclosan eluting, Percuflex Plus or Optima ureteral stent was placed intravesically. Urine was cultured on days 1, 3 and 7. On day 7 the stents were assessed for encrustation and viable organisms, while the bladders were scored for the degree of inflammation.Throughout the study urine isolated from the triclosan group contained significantly fewer viable organisms than controls with 7 of 13 animals completely clearing the infection by day 7. Similarly 9 of 13 triclosan eluting stents showed no viable organisms upon recovery and the remaining 4 showed significantly fewer organisms than controls. Urine and stents in all controls were positive for P. mirabilis at all time points. Although there was no significant difference in encrustation among the groups, bladders harvested from the triclosan group demonstrated significantly less inflammation.Triclosan eluting stents greatly decreased P. mirabilis growth and survival in a rabbit UTI model compared to controls. These stents may prove useful for decreasing device related P. mirabilis UTIs.

Current urinary stone analysis techniques are limited in their abilities to simultaneously characterize composition and structure. Laboratory techniques such as IRS and x-ray diffractometry require small powdered samples for analysis, rendering composition results dependent on the choice of sample and its preparation. We investigated the application of x-ray CS analysis to identify topographic urinary stone composition ex vivo. CS is essentially a transmission based x-ray diffractometry method that depends on molecular structure and, therefore, can distinguish different compounds. Diagnostic x-ray equipment facilitates the examination of structural arrangements of minerals in intact calculi.Tomographic images of intact calculi CS properties were acquired with a purposely built scanner. Composition is extracted from CS by fitting a library of common pure stone component CS signatures to those of the unknown sample in each image pixel. Two zones per stone were isolated (powdered) for IRS composition analysis for comparison with CS maps at these locations. Each stone was also independently analyzed for bulk composition by IRS analysis.CS composition maps revealed the spatial arrangement of minerals in intact calculi. IRS results showed good agreement with CS in the selected regions of interest. Bulk composition by IRS was noted to miss some important stone components, indicating that the choice of sample may skew composition results.CS from diagnostic x-rays can be used to identify structure and composition in mixed urinary calculi nondestructively. The tissue specific CS images presented support the development of CS analysis as a means of identifying stone composition characteristics in the laboratory.

Founded in 1881,1 the Department of Surgery is one of the largest departments in the Schulich School of Medicine & Dentistry at Western University. Housing 8 divisions, the department has experienced tremendous growth in the past 10 years. Several endowed chairs have been established in recent years, such as the J.C. Kennedy Chair in Orthopaedic Surgery, the Sandy Kirkley Chair in Musculoskeletal Research, the Graham King Musculoskeletal Research Chair and the Ray and Margaret Elliott Chair in Surgical Innovation. Through international initiatives in education, research and surgical advancements, the international profile of the department has increased substantially. With a long history of surgical innovation2 and providing high-quality patient-centred care, the department has become a sought-after training opportunity.

A variety of devices are currently available for intracorporeal stone fragmentation. Recently a new wavelength of laser, the Holmium:YAG, has demonstrated a variety of potential urologic applications including ablation of soft tissue lesions as well as stone fragmentation. This laser has a wavelength of 2100 nm and operates in a pulsed mode. Energy is delivered through a 400 um quartz end-firing fiber. In this presentation we review our clinical experience with the Holmium:YAG laser for the treatment of renal and ureteral calculi. Over a 23 month period, 63 patients underwent 67 procedures. Seven procedures consisted of percutaneous nephrolithotripsy for large or staghorn renal calculi. Sixty procedures were performed for ureteral stones. Procedures for proximal ureteral stones (6) employed a retrograde approach using flexible ureteroscopes (8.5 or 9.8). Stones in the mid ureter (12) and distal ureter (42) were approached transurethrally using a 6.9 rigid ureteroscope. Complete stone fragmentation without the need for additional procedures was achieved in 82% of cases. Treatment failures included 1 stone migration into the renal pelvis during laser activation, 6 patients who had incomplete fragmentation and 3 patients in which laser malfunction precluded complete fragmentation. Stone analysis available in 23 patients revealed calcium oxalate monohydrate (15), calcium oxalate dihydrate (2), cystine (2), uric acid (3) and calcium phosphate (1). A single complication of ureteral perforation occurred when the laser was fired without direct visual guidance. Radiographic follow-up at an average of 16 weeks is available in 22 patients and has identified 2 patients with ureteral strictures that are not believed to be related to laser lithotripsy. In summary, we have found the Holmium:YAG laser to be a reliable and versatile device for intracorporeal lithotripsy. Its safety and efficacy make it a suitable alternative for performing intracorporeal lithotripsy of urinary calculi.

Objectives The preoperative planning of partial nephrectomy can be facilitated by the ability to view the tumor and surrounding tissue in three-dimensional (3D) virtual reality (VR). A technique to convert Digital Imaging and Communications in Medicine computed tomography scan data into a fully 3D VR environment was developed. The model can be transferred to a personal computer, allowing the surgeon to view the 3D model in the operating room. Methods Computed tomography data from a patient with multifocal renal masses was converted into a 3D polygonal mesh using Amira running on a desktop personal computer with Windows XP Professional. A Silicon Graphics Monster Onyx2 running the Linux operating system was used to view the 3D stereo model in the VR environments: either the CAVE or a specialized desk called the Immersadesk. An application to view and interact with the model on a desktop personal computer was written in C++. Results A 3D model of the kidney, the multiple tumors, and the associated systems was created. The model could be viewed and manipulated in a true VR environment and on a desktop personal computer. Conclusions This project completed two major goals. First, a 3D model of a kidney containing multiple masses was created and viewed in a VR environment. Second, an interface to display the model on a desktop personal computer in the operating room was created. This is the first step in bringing VR technology to the operating room to assist the surgeon directly.

SELDI‐TOF‐MS is a highly sensitive protein‐analysis tool capable of detecting minute protein profile differences between biological samples. As proteins have been associated with urinary tract calculi, protein‐based urinalysis may offer insights into their diagnosis. The purpose of this study was to evaluate SELDI‐TOF‐MS as a potential method for identifying urinary biomarkers of urolithiasis. Midstream sterile urine samples were obtained from 25 male patients with a confirmed diagnosis of urolithiasis (test group) and 25 male subjects with no known history of the disease (controls). Urinary levels of oxalate, total protein, albumin, and osteopontin were determined. Protein profiles were generated using SELDI‐TOF‐MS. SELDI‐TOF‐MS profiling revealed a relationship between protein peak intensities at 67 and 24 kDa that differed between the two groups. The ratio of p67:p24 was found to be less than 1.0 in all of the control samples (mean 0.26), while 18 out of 25 (72%) of the test group samples displayed a ratio greater than 1.0 (total group mean 4.75, P

Advances in ureteroscope design and refinements of ancillary instrumentation have resulted in an expanded role for ureteroscopy in the management of urinary calculi. Technological enhancements coupled with improved endourologic skills have also been associated with a reduction in procedural-related complications. Historically, postoperative imaging with ultrasound (U/S) or intravenous pyelogram (IVP) had been advocated to rule out persistent obstruction due to retained stone fragments or ureteral stricture. The purposes of this study were to evaluate the incidence of postoperative ureteral obstruction in a contemporary series of patients undergoing ureteroscopic holmium:YAG laser lithotripsy without basket extraction of fragments and to identify patient, stone and operative factors predictive of which patients will benefit from postoperative imaging.The charts and imaging studies of 89 consecutive patients undergoing a total of 94 holmium:YAG ureteroscopic lithotripsy procedures between December 1998 and December 2000 were retrospectively reviewed. Preoperative, intraoperative and postoperative data were collected and analyzed. The primary outcome measure was the incidence of postoperative ureteral obstruction documented on upper tract imaging. Secondary outcome measures included interventions required for postoperative obstruction and other nonobstructive postoperative complications.Twenty-eight females and 61 males were studied, with a mean patient age of 54 (range 13-80) years. Fifty-five percent of patients underwent related procedures prior to referral to our tertiary endourology centre. Complete clinical and radiological follow-up is available for 68 of 89 (76.4%) patients, with a mean follow-up duration of 24.2 weeks. Overall stone-free rate was 97%. Six patients had evidence of urinary tract obstruction on follow-up radiological assessment, two from residual stone fragments and four from ureteral stricture. Each of these four patients had at least one preoperative risk factor for ureteral stricture.Routine postoperative upper tract imaging is not necessary in all patients undergoing uncomplicated ureteroscopic holmium:YAG laser lithotripsy. Indications for upper tract imaging include chronic stone impaction, significant ureteral trauma, pre-existing renal function impairment, endoscopic evidence of stricture and postoperative flank pain or fever.

The long-term placement of biomaterials within the urinary tract is limited by the development of encrustation. In a noninfected urinary environment, encrustation often results from the deposition of calcium oxalate on the biomaterial surface. There is an association between the absence of Oxalobacter formigenes, a commensal colonic bacterium capable of degrading oxalate, and calcium oxalate stone formation. This pilot study was designed to evaluate several oxalate-degrading enzymes produced by O. formigenes as a potential biomaterial coating to reduce urinary tract encrustation.Circular silicone disks of 6-mm diameter were incubated for 48 hours in oxalylcoenzyme A decarboxylase (OXC), formyl-coenzyme A transferase (FRC), and coenzyme A, while control disks were incubated in distilled water. The adsorption of OXC and FRC was assessed using enhanced chemiluminescence (ECL) and atomic force microscopy (AFM). Coated and uncoated disks (20 of each) were implanted in the bladders of 40 female New Zealand White rabbits. After 30 days, the disks were recovered, and the degree of encrustation on the polymer surface was evaluated utilizing dry weight measurement, calcium atomic absorption spectroscopy (AAS), and scanning electron microscopy/energy-dispersive X-ray analysis (SEM/EDX).Both ECL and AFM demonstrated coating of the silicone disks with OXC and FRC. The mean dry weights of the coated and control disks following explantation were 0.591 +/- 0.438 g and 0.747 +/- 0.428 g, respectively (P = 0.307). The mean weight of calcium on the coated and control disks, as determined by AAS, was 154.1 +/- 96.25 mg and 258 +/- 181.35 mg, respectively (P = 0.008).The use of oxalate-degrading enzymes from O. formigenes to coat urinary biomaterials represents a novel paradigm to reduce biomaterial-related encrustation. Coating of silicone with oxalate-degrading enzymes from O. formigenes results in a modest reduction in encrustation with no apparent toxicity. Further studies are warranted.

Objectives To assess the long-term efficacy of percutaneous antegrade endopyelotomy for the treatment of ureteropelvic junction (UPJ) obstruction performed at a single institution during a 10-year period. We provide alterations in investigation and management strategies on the basis of the results. Methods From July 1990 to June 2001, 80 patients with clinical and radiographic evidence of UPJ obstruction underwent percutaneous endopyelotomy for the treatment of primary (n = 61) or secondary (n = 19) UPJ obstruction. The mean patient age was 35 years (range 4 to 76). Percutaneous endopyelotomy was performed in a standard fashion using either a hooked-knife (n = 77) or holmium laser (n = 3). Results With a mean patient follow-up of 55 months (range 16 to 138), the overall success rate was 67% (53 of 79). The success rate for primary and secondary UPJ obstruction was 65% (39 of 60) and 74% (14 of 19), respectively. The mean time to failure was 15 months (range 1 to 79). Operative intervention for 24 of 26 patients with failure included open pyeloplasty (n = 18, 75%), indwelling ureteral stenting (n = 2, 8%), retrograde balloon dilation (n = 1, 4%), and nephrectomy (n = 3, 13%). Two asymptomatic patients with recurrent radiographic evidence of obstruction elected conservative follow-up. Significant crossing vessels were encountered at open pyeloplasty in 15 (83%) of 18 patients. Conclusions Our long-term results of percutaneous endopyelotomy demonstrated somewhat lower success rates than that reported in published studies. Long-term follow-up is critical in identifying late failures. The high prevalence of crossing vessels encountered at open pyeloplasty provided further evidence to support its role in endopyelotomy failure. Routine preoperative helical computed tomography to detect significant crossing vessels is recommended. Patients with crossing vessels are likely better served with operative techniques that specifically address this issue, namely open or laparoscopic pyeloplasty.

A case of hydrocele infection secondary to a cutaneous b-hemolytic group A streptococcal infection is described in a renal transplant recipient. Sepsis and renal failure occurred in the setting of this severe, life-threatening infection. This case represents the first description of a group A streptococcal hydrocele infection in an adult. This type of infection can progress rapidly to sepsis and its attendant complications, especially in an immunocompromised patient. Early diagnosis and treatment is crucial in order to optimize the outcome.

Biomaterials such as urethral catheters, urethral stents, and ureteral stents are commonly used in patients with urologic disorders. There are currently many different bulk materials and coatings available for the manufacture of urinary tract biomaterials; however, the ideal material has yet to be discovered. Any potential biomaterial must undergo rigorous physical and biocompatibility testing before commercialization and use in humans. Despite significant advances in basic science research involving biocompatibility issues and biofilm formation, infection and encrustation remain associated with the use of biomaterials in the urinary tract, and therefore, limit their long-term use. This review critically evaluates the literature published over the past 12 months, providing an update on the current status of naturally derived and synthetic polymeric biomaterial use in the urinary tract. We focus on urethral catheters, urethral stents, and ureteral stents. We discuss issues of biocompatibility and new approaches to biocompatibility testing, biomaterials currently available for use, new biomaterials and coatings, and novel ureteral stent designs. Finally, we discuss the future of biomaterial use in the urinary tract.

Surgical simulation has emerged in the last decade as a potential tool for aiding acquisition of technical skills, including anesthesia protocols, trauma management, cardiac catheterization and laparoscopy. We evaluate and validate the use of a computer based ureteroscopy simulator (URO Mentor, Simbionix Ltd., Lod, Israel) in the acquisition of basic ureteroscopic skills.We assessed 20 novice trainees for the ability to perform basic ureteroscopic tasks on a computer based ureteroscopy simulator. Participants were randomized to receive individualized mentored instruction or no additional training, and subsequently underwent post-testing. Pre-training and post-training improvement in performance was assessed by objective simulator based measurements. Subjective overall performance was rated using a validated endourological global rating scale by an observer blinded to subject training status.Demographics and pre-test scores were similar between groups. Post-testing revealed a significant effect of training on objective and subjective measurements. Spearman rank correlation demonstrated a significant association between objective simulator based measurements and the endourological global rating scale.Use of a computer based ureteroscopy simulator resulted in rapid acquisition of ureteroscopic skills in trainees with no prior surgical training. Results of this study demonstrate the use of a virtual reality ureteroscopy simulator in endourological training. Correlation of simulator based measurements with a previously validated endourological global rating scale provides initial validation of the ureteroscopy simulator for the assessment of ureteroscopic skills.

Objectives. To review the results of holmium laser lithotripsy in a cohort of patients who presented with symptomatic urolithiasis in pregnancy. Symptomatic urolithiasis in pregnancy that does not respond to conservative measures has traditionally been managed with ureteral stent insertion or percutaneous nephrostomy. Holmium:yttrium-aluminum-garnet (YAG) laser lithotripsy using state-of-the-art ureteroscopes represents an emerging strategy for definitive stone management in pregnancy. Methods. A retrospective analysis was conducted at two tertiary stone centers from January 1996 to August 2001 to identify pregnant patients who were treated with ureteroscopic holmium laser lithotripsy for symptomatic urolithiasis or encrusted stents. Eight patients with a total of 10 symptomatic ureteral calculi and two encrusted ureteral stents were treated. The mean gestational age at presentation was 22 weeks. The mean stone size was 8.1 mm. The stones were located in the proximal ureter/ureteropelvic junction (n = 3), midureter (n = 1), and distal ureter (n = 6). Results. Complete stone fragmentation and/or removal of encrusted ureteral stents were achieved in all patients using the holmium:YAG laser. The overall procedural success rate was 91%. The overall stone-free rate was 89%. No obstetric or urologic complications were encountered. Conclusions. Ureteroscopy and holmium laser lithotripsy can be performed safely in all stages of pregnancy, providing definitive management of symptomatic ureteral calculi. The procedure can be done with minimal or no fluoroscopy and avoids the undesirable features of stents or nephrostomy tubes.

Coherent scatter properties depend on the molecular structure of the scattering medium and measured scatter patterns are often characteristic of a chemical species. We explored the usefulness of coherent scatter analysis as a basis for identifying urinary calculus composition.A laboratory system for collecting coherent scatter signals from biological specimens was developed. This technique uses a diagnostic x-ray tube and image intensifier, and measures coherent scatter from intact renal stones. The coherent scatter signatures of 6 common stone components (calcium oxalate monohydrate, calcium phosphate, calcium phosphate dihydrate, cystine, magnesium ammonium phosphate and uric acid) were acquired from pure chemical samples and stones identified by infrared spectroscopy as having a uniform composition. In addition, a sample of calculus identified as containing only calcium oxalate dihydrate was examined. The same fragmented stone samples analyzed by infrared spectroscopy were scanned using coherent scatter.In each case the scatter patterns from powdered chemicals and fragmented stones showed circular symmetry and consisted of a series of broad rings of various intensities. Each pure chemical sample produced a distinct coherent scatter pattern. The signatures of the stone specimens closely agreed with those of the chemical samples.These initial results indicate that coherent scatter analysis using diagnostic x-rays has potential as a tool for urinary calculous composition identification. Further developments in this technique may have the potential for determining the composition of a calculus in vivo before therapy, thus, aiding in therapy planning.

We assessed the effectiveness and safety of holmium:YAG laser lithotripsy for managing upper urinary tract calculi in a prospective cohort of 598 patients.Ureteroscopic holmium:YAG laser lithotripsy was performed in 598 patients between 1993 and 1999. Calculi were located in the distal ureter in 39.6% of cases, mid ureter in 18.6%, proximal ureter in 32.4% and kidney in 9.4%. Patients were treated on an outpatient basis with various flexible and semirigid endoscopes. Of the cases 59% were referred as previous treatment failures. Patients were assessed 6 to 12 weeks postoperatively with repeat plain x-ray and ultrasound or excretory urography for late obstructive complications.The overall stone-free rate was 97%. As stratified by location, the stone-free rate was 98% in the distal ureter, 100% in the mid ureter, 97% in the proximal ureter and 84% in the kidney. Fragmentation was incomplete in 6% of cases and secondary intervention was required in 6%. The overall complication rate was 4%. New onset ureteral stricture developed postoperatively in 0.35% of patients.Holmium:YAG laser lithotripsy is a highly effective and safe treatment modality for managing ureteral and a proportion of intrarenal calculi on an outpatient basis. The effectiveness and versatility of the holmium laser combined with small rigid or flexible endoscopes make it our modality of choice for ureteroscopic lithotripsy.

To determine if 20 mL of 2% intraurethral lidocaine gel is superior to 10 mL of 2% lidocaine or sterile lubricant for flexible cystoscopy in men.A randomized, double-blind, placebo-controlled trial was conducted. Sixty men scheduled to undergo diagnostic flexible cystoscopy were randomized to receive either 20 mL of placebo gel (Group I), 10 mL, of 2% lidocaine gel (Group II) or 20 mL of 2% lidocaine gel (Group III). A penile clamp was applied for 15 minutes to ensure consistent indwelling time in all patients. Patients recorded their pain on a 10-cm non-graphical visual analog scale prior to cystoscopy as a baseline, during the procedure, and immediately after the procedure. Patients also recorded their pain and willingness to have the same anesthetic on a 4-point descriptive scale. Heart rate and mean arterial blood pressure (MAP) were recorded at specific intervals throughout the procedure, and increases in mean arterial pressure were considered objective evidence of patient pain.Pain perception was not statistically different in the groups (Group I 4.65, Group II 3.93, Group III 3.57; P = 0.406). Pain assessment and willingness to have the same anesthetic also did not differ statistically among the groups. Similarly, differences in the increases in MAP were not statistically significant between groups.Instillation of 20 mL or 10 mL of 2% lidocaine gel has no advantage over plain lubricant in providing anesthesia for flexible cystoscopy in men.

We evaluated the serum renal biochemical profile as an indicator of unrecognized laparoscopic bladder injury in four women. The patients were seen 24 to 56 hours postoperatively with elevated serum creatinine and urea levels, and electrolyte changes compatible with acute renal dysfunction. The mechanism responsible for these biochemical changes appears to be extravasation and reabsorption of urine. Biochemical values returned to normal within 24 hours after bladder repair.

Since the introduction and widespread use of extracorporeal shockwave lithotripsy (SWL), various complications have been noted. Perinephric hematoma and ureteral obstruction may be anticipated by urologists as potential problems. We report the first case of perinephric abscess encountered after 17 895 SWL treatments at our institution. A 65 year old woman presented 4 months following a second SWL procedure with a perinephric abscess and was successfully treated with percutaneous drainage. A review of the English literature revealed only 3 other cases of perinephric abscess following SWL. This diagnosis should be considered in early and late presentations of flank pain following SWL.

Appendicovesical fistulae are rare and occur secondary to acute or missed acute appendicitis. A 15 year old boy presented with urinary symptoms and a pelvic abscess on imaging studies. At laparotomy an appendicovesical fistula was encountered and was successfully managed by a right colectomy and ileal transverse colon anastomosis. The presentation and management of appendicovesical fistula is discussed.

Renal calculous disease is an infrequent but not insignificant occurrence during pregnancy. In 50 to 80% of the cases conservative management is appropriate and the stone will pass spontaneously. Should intervention be required, recent advances in stone management and techniques for urinary tract drainage may be successfully applied to the obstetric population. Concerns regarding surgical and anesthetic risks, and the potential hazards of radiation exposure during pregnancy favor a minimally invasive approach with definitive treatment late in pregnancy or post partum. We review our experience during a 5-year period in managing 29 patients with urinary calculous disease during pregnancy. Based on our experience and review of the literature an algorithm for treatment of urolithiasis during pregnancy is proposed.

A new percutaneous approach for the management of stone-containing caliceal diverticula is described that was used successfully in three patients with symptomatic calculi. Access to the stones was achieved via transdiverticular puncture into the renal collecting system, allowing a guidewire to be manipulated down the ureter to provide secure access for the stone-removal procedure. Prolonged probing with a wire for the neck of the diverticulum was avoided and secure access to the diverticulum quickly achieved.

This review focuses on technological advances and relevant research related to ureteral stents. The importance of physical and chemical biomaterial type, biocompatibility, material coatings such as hydrogels, and infection related to indwelling ureteral stents are discussed. Recent in vitro and in vivo research has focused on materials that will reduce encrustation and bacterial biofilm formation. The adsorption of antimicrobials onto devices holds promise of reducing infection rates, but multidrug resistant bacteria, short leaching times and adverse side effects make it essential that alternative strategies be investigated. Just so, encrustation limits the long-term use of urinary materials, and a better understanding of factors involved in encrustation are needed to reduce the problem.

The treatment options available for managing bladder calculi include transurethral cystolithotripsy, open cystolithotomy, and shockwave lithotripsy. For larger calculi, transurethral treatment can be time consuming, and the manipulation has the potential to cause urethral injury. Percutaneous suprapubic cystolithotripsy represents another treatment option for bladder calculi which is effective and minimally invasive.Fifteen patients had bladder calculi treated with percutaneous cystolithotripsy over a 3-year period. The mean stone size was 39 mm (range 10-64 mm). Stones were single in seven patients and multiple in eight patients. The indications for cystolithotripsy were stone size3 cm, multiple stones1 cm, and inability to perform transurethral cystolithotripsy because of patient anatomy. Percutaneous suprapubic cystolithotripsy was done through either a 30F or a 36F cystotomy tract. Fragmentation and removal was performed with a 26F rigid nephroscope and the pneumatic Swiss Lithoclast. Suprapubic and urethral catheters were placed postoperatively in all patients.Each patient was cleared of the stone burden with a single procedure, and there were no major complications. The mean duration of suprapubic catheterization was 2.6 (range 1-5) days.Percutaneous suprapubic cystolithotripsy is an effective and safe technique for treating large bladder calculi. It is minimally invasive, avoids urethral injury, and, in combination with the pneumatic Swiss Lithoclast, can be used to fragment and remove large and hard bladder calculi.

The stone-free rate after extracorporeal shock wave lithotripsy (ESWL††Dornier Medical Systems, Inc., Marietta, Georgia.) is primarily determined by a plain abdominal radiograph alone. However, the accuracy of that assessment can be challenged by renal tomography and flexible nephroscopy. We report on 29 patients with large renal calculi treated with a combination of percutaneous nephrolithotripsy and ESWL. Stone-free rates were determined by plain abdominal radiograph, renal tomography and flexible nephroscopy. The plain abdominal radiograph and renal tomography overestimated stone-free rates by 35% and 17%, respectively, compared to flexible nephroscopy. To determine stone-free rates after ESWL renal tomography is superior to a plain abdominal radiograph alone. Also, among patients with large renal calculi the use of the flexible nephroscope markedly improves the stone-free rate.

With the development of small-caliber ureteroscopes and lithotripsy devices, it is now possible to perform intracorporeal stone fragmentation without dilatation of the ureteral orifice. Ureteral stones are typically fragmented into small particles that can be difficult to retrieve for stone analysis. Infrared spectroscopy (IRS) of the precipitate from urine after intracorporeal lithotripsy represents a method for obtaining stone analysis.A total of 69 patients underwent ureteroscopic lithotripsy with the holmium laser or the electrohydraulic probe for stones in the ureter (N = 65) or kidney (N = 4). Each patient's bladder was then drained and the urine filtered. The resulting precipitate was analyzed using IRS.The amount of material for analysis wasor =1 mg in 56 patients (82%). Stone composition was positively identified in 44 patients (64%). Material suitable for analysis was recovered from 73% of patients when the bladder was drained with a cystoscope sheath compared with 43% when a urethral catheter was used (P = 0.03). There was no significant difference in pretreatment stone size in the patients who had a positive v a negative result (11.7 mm v 10.9 mm; P = 0.06). Similarly, the stone location was not significantly related to the likelihood of positive analysis (P = 0.29).Straining the urine after ureteroscopic intracorporeal lithotripsy and analyzing the precipitate with IRS is able to identify stone composition in the majority of patients. This method is especially useful in the setting of holmium laser lithotripsy, in which the majority of the stone is converted to spontaneously passable particles.

Purpose: Many kidney stones have a heterogeneous composition in layers about a central core. At present, infrared spectroscopy (IRS) or conventional x‐ray diffractometry are used to determine stone composition which is required to determine appropriate follow‐up care for recurrence prevention. Both methods are limited requiring that stones be crushed prior to examination and a bulk measure of composition is obtained. We are currently conducting a clinical trial using coherent‐scatter computed tomography (CSCT) as an ex‐situ technique of stone analysis. We believe this technique will provide detailed structural information, including the initial nucleating mineral at the core of the stone. Method and Materials: Our ongoing prospective trial examines urinary calculi from 100 consecutive eligible patients undergoing either percutaneous nephrolithotripsy or ureteroscopy. All calculi removed intra‐operatively are analyzed with CSCT and then the same samples are sent for IRS (the standard of care at our center). Stone analyses from the two modalities are compared for overall bulk composition and the CSCT data analyzed to determine composition of the core. Results: Of the first 25 stones examined, 12 had core minerals that were not the primary component reported by IRS. In four, IRS reported 100% cystine where CSCT showed a distinct UA core inside cystine. In another, IRS reported 85% struvite while CSCT showed a calcium oxalate monohydrate core inside a struvite outer layer. Conclusion: We are finding a significant fraction of stones in which IRS does not report the mineral component at the core of the stone as a large component of bulk composition. This raises the question whether recurrence rates could be improved by targeting the core component.

To review the physics related to the holmium laser, its laser-tissue interactions, and its application to the treatment of urological diseases.The holmium: YAG laser is a solid-state, pulsed laser that emits light at 2100 nm. It combines the qualities of the carbon dioxide and neodymium:YAG lasers providing both tissue cutting and coagulation in a single device. Since the holmium wavelength can be transmitted down optical fibers, it is especially suited for endoscopic surgery.The authors provide a review of the literature as it relates to the holmium laser and its application to urology.The holmium wavelength is strongly absorbed by water. Tissue ablation occurs superficially, providing for precise incision with a thermal injury zone ranging from 0.5 to 1.0 mm. This level of coagulation is sufficient for adequate hemostasis. The most common urologic applications of the holmium laser that have been reported include incision of urethral and ureteral strictures; ablation of superficial transitional cell carcinoma; bladder neck incision and prostate resection; and lithotripsy of urinary calculi.The holmium: YAG laser is a multi-purpose, multi-specialty surgical laser. It has been shown to be safe and effective for multiple soft tissue applications and stone fragmentation. Its utilization in urology is anticipated to increase with time as a result of these features.

Spatial anatomy of the lower renal pole, as defined by the infundibulopelvic angle (LIP angle), infundibular length (IL), and infundibular width (IW), plays a significant role in the stone-free rate after shockwave lithotripsy. A wide LIP angle, a short IL, and a broad IW, individually or in combination, favor stone clearance, whereas a LIP70 degrees, an IL3 cm, or an IWor =5 mm are individually unfavorable. When all three unfavorable factors or an unfavorable LIP and IL coexist, the post-SWL stone-free rate falls to 50% or less. Using these criteria, more than one fourth of our patients with a lower-pole calculus might have been better served by an initial percutaneous or perhaps ureteroscopic procedure, neither of which is significantly affected by the lower-pole spatial anatomy.

Objectives. To study the efficacy and safety of a new transurethral microwave thermotherapy device (the Urowave) in the treatment of men with clinical benign prostatic hyperplasia (BPH) in a randomized, double-blind, sham-controlled trial. Methods. A total of 220 patients (mean age 66.2 years) with clinical BPH, an American Urological Association symptom index (AUA SI) of 13 points or more, and a peak flow rate of 12 mL/s or less were enrolled and randomized 2:1 for active versus sham treatment. All treatments were conducted as an outpatient procedure under local anesthesia, with oral sedation and analgesia only. Patients were followed up at 1 week and 1, 3, and 6 months after treatment. Results. The treatments were well tolerated, and no patient received general or spinal anesthesia. The AUA SI dropped from 23.6 to 12.7 points at 6 months (P

The development of a reliable, minimally invasive method of distinguishing physiologically significant renal obstruction from dilation without obstruction would have important clinical implications. As it is well known that renal blood flow decreases over time in the presence of obstruction, we investigated the ability of color flow Doppler ultrasonography and dynamic contrast-enhanced CT scanning to detect changes in blood flow in unilaterally obstructed porcine kidneys. In the initial phase of this study, the effect of acute unilateral obstruction were studied in nine pigs. The resistive index (RI) was measured with Doppler ultrasonography, and renal blood flow was quantitated with dynamic CT using tracer kinetic principles and deconvolution. The RI measurements were unable to distinguish between the obstructed kidneys and their controls. Dynamic CT scanning demonstrated a greater fall in blood flow in the obstructed kidney, and this change was significantly different from baseline. The same findings were supported by radiolabelled microsphere blood-flow measurement. In the chronic portion of the study, after surgical creation of a partial ureteric obstruction, the kidneys were studied by both techniques at 1, 2, and 3 weeks. Again, RI was unable to demonstrate any difference between obstructed and unobstructed kidneys, while CT showed a progressive fall in blood flow in each successive week that was statistically significant. Dynamic contrast-enhanced CT scanning is a promising diagnostic tool that might be used to distinguish a functionally significant renal obstruction from nonobstructive dilation. Further clinical studies to validate this technique are warranted.

Although endoscopic lithotripsy of bladder stones has been well described and is widely practiced, comparison of the main modalities of mechanical, electrohydraulic, and ultrasonic lithotripsy is lacking. The exact role of these and other modalities such as the Swiss Lithoclast and extracorporeal shockwave lithotripsy is not clearly defined. The safety and efficacy of the various lithotripsy modalities available to treat bladder calculi were reviewed retrospectively over an 18-year period. A total of 106 patients were treated with some form of intracorporeal lithotripsy. In general, all devices proved to be effective with a low rate of complications. The addition of transurethral resection of the prostate to bladder stone management under the same anesthetic was also found to be a safe procedure for moderate benign prostatic hyperplasia. In summary, transurethral endoscopic lithotripsy is a safe and effective method of bladder stone management both alone and in combination with transurethral prostatectomy. All modalities of intracorporeal lithotripsy are effective; however, devices such as ultrasound lithotripters or the Swiss Lithoclast that utilize larger, rigid probes may be more efficient for patients with large or particularly hard vesical calculi.

Electrohydraulic lithotripsy (EHL) of ureteral calculi has proved to be an effective and relatively inexpensive method of intracorporeal lithotripsy. However, the potential for significant ureteral injury is an everpresent concern with conventional EHL. The electromechanical impactor (EMI), an innovative modification of a standard EHL probe, has been shown in initial investigations to be capable of fragmenting urinary calculi with a greater margin of safety. Herein, we describe our preliminary experience with this new device in 23 patients with ureteral calculi. In nine patients selected to undergo EMI treatment, the device could not be employed because of either inability to access the stone with the large endoscope required (six cases) or device malfunction (three cases). Among the patients in whom the EMI was used, five required an additional modality of intracorporeal lithotripsy to complete stone fragmentation. In the remaining nine patients, stone fragmentation was achieved with the EMI as the sole modality of lithotripsy, for an overall success rate of 39% (9/23). There were no complications directly related to use of the EMI as noted endoscopically or on postoperative imaging. The EMI appears to be a safe device for intracorporeal lithotripsy. Its application to a large population of patients with ureteral stones may be limited by the probe size (5F), which precludes its use with the smaller rigid and flexible ureteroscopes.

The ideal surgical laser for the treatment of soft tissue pathology should possess both ablative and hemostatic abilities. As well, for use in urologic conditions the laser must also be suitable for endoscopic use. The Holmium:YAG laser possesses these qualities and in preliminary clinical use has demonstrated a variety of potential urologic applications. In this study we review our initial experience with the Holmium:YAG laser over a 18 month period. A total of 51 patients underwent 53 procedures for a variety of soft tissue conditions including: bladder tumor ablation (25), incision of ureteral stricture (15), incision of urethral stricture (6), treatment of ureteropelvic junction obstruction (3), incision of bladder neck contracture (2), and ablation of a ureteral tumor (2). Satisfactory hemostasis was achieved in all cases. Procedures were considered successful (no further intervention being required to treat the condition) in 81% of the cases. Two patients with dense bladder neck contractures required electroincision under the same anesthetic for completion of the procedure. A single complication, that of urinary extravasation following incision of a urethral stricture resolved with conservative management. In summary, the Holmium:YAG laser has demonstrated safety and proficiency in the treatment of a variety of urologic soft tissue conditions.

Currently three modalities are available for intracorporeal stone fragmentation--electrohydraulic, ultrasound and laser lithotripsy. A new device, the Swiss Lithoclast, has been developed by the Departments of Medical Electronics and Urology at the University of Lausanne, Switzerland. This device has been used clinically in several countries for the treatment of stones throughout the human urinary tract. While no adverse outcomes have been reported, the potential tissue effects of the device have not been thoroughly investigated in an animal model. The objective of the present study is to evaluate the possible acute and long-term tissue effects of this instrument on the pig urinary tract. In all acute animals, visible mucosal lesions were seen at the site of probe firing in the bladders and ureters. Histologic examination demonstrated the effects of acute trauma with edema, hemorrhage and mucosal denudation. No significant long-term tissue effects were noted either pathologically or on radiographs in the 3- and 6-week animals. This study confirms our clinical impression that the Swiss Lithoclast effectively fragments urinary calculi and is associated with a large margin of safety.