How I Do It: ERAS protocol featuring erector spinae plane block for percutaneous nephrolithotomy.

Percutaneous nephrolithotomy (PCNL) is the gold-standard treatment for large and complex renal stones. Though associated with higher stone-free rates compared to other minimally invasive stone procedures, this comes at the expense of increased morbidity including postoperative pain and discomfort. We describe our enhanced recovery after surgery (ERAS) protocol for PCNL with emphasis on the use of erector spinae plane blocks to improve patient satisfaction and reduce postoperative opioid use and bother.

Prospective Randomized Trial of Antibiotic Prophylaxis Duration for Percutaneous Nephrolithotomy in Low-Risk Patients.

Introduction and Objective: Postoperative infection and sepsis account for the most common complications following percutaneous nephrolithotomy (PCNL), as high as 14% in low-risk patients. Although the American Urological Association (AUA) recommends perioperative antibiotics for 24 hours or less for PCNL, practice patterns vary regarding duration of antibiotic therapy. We aimed to compare the efficacy of 24-hour antibiotic coverage vs short-course protocol of antibiotic prophylaxis for PCNL. Materials and Methods: Low-risk patients with a sterile preoperative urine culture undergoing PCNL were prospectively randomized to antibiotics for up to 24 hours after procedure (24Hr) or continued until external urinary catheters were removed (CR) study groups. Patients were given a first generation cephalosporin, or ciprofloxacin in patients with penicillin allergy. Exclusion criteria included age <18 years, receiving antibiotics immediately before the procedure, history of urosepsis, presence of indwelling catheter >1 week, multistage procedure, immunosuppression, pregnancy, multiple antibiotic allergies, and patients who are breastfeeding. Results: Ninety-eight patients were randomized to either 24Hr (n = 49) or CR (n = 49). Mean duration of antibiotic administration was 20.6 and 34.0 hours in the 24Hr and CR groups (p = 0.04), respectively. Age, comorbidities, stone size, operative time, number of punctures, dilations, and proportion of "tubeless" procedures were similar between groups. There were no differences in febrile episodes, rates of systemic inflammatory response syndrome, bacteremia, or culture-proven postoperative urinary tract infection between the 24Hr and CR groups. Overall complication rates were similar between groups. In a subgroup analysis which excluded "tubeless" patients (24 and 29 patients in 24Hr and CR groups, respectively), no differences were seen in postoperative outcomes. Conclusions: In a randomized, prospective study, we found that a 24-hour protocol for antibiotic prophylaxis is not associated with increased risk of infection-related events compared to giving antibiotics until external catheters are removed in patients with low infectious risk undergoing PCNL. Clinicaltrials.gov: NCT02579161.

Utility of Frailty Assessment in Urologic Stone Surgery: A Review of the Literature.

Introduction and Objective: As life expectancy continues to rise, the prevalence of frailty is also increasing. The idea of frailty and its effect on the operative patient has been previously studied, but not regularly incorporated into routine practice. We present a review on frailty metrics in the literature, validated assessment methods, and simplified screening tools to better predict and optimize patient outcomes. Methods: An online PubMed search was conducted by three authors (T.A., T.G.R.B., M.M.) for overall frailty, frailty assessment, and preoperative risk assessment. Only English publications were included in the analysis. Full-text analysis was then conducted by all three authors to validate the data. Results: An abundance of literature was found on frailty. Even though some methods are validated as extremely effective for assessing frailty, they may be time-consuming and require a specialist. Various quick screening methods are also presented, many already validated, and should be utilized by urologists more regularly. Conclusions: Multiple studies demonstrate the relationship between frailty and surgical patients' outcome. Many quick, office-based, validated tools to screen for frailty are described, and should be incorporated into our practice in appropriate patients. Future research is now focused on the concept of "prehabilitation" to improve patient frailty status in the preoperative setting, and consequently operative outcomes.

LeGrand N. Denslow: Pioneer in dermatology or charlatan?

LeGrand N. Denslow (1852-1918) was a pioneer of American dermatology and one of its most controversial figures. His professional career revolved around the cities of New York; St. Paul; Minnesota; and London, England. In 1885, he became professor of skin diseases and genitourinary surgery, and secretary of the St. Paul Medical College, thus making him one of the earliest dermatologists to practice in the state of Minnesota. In 1908, Denslow created a sensation in the news media when he announced, in a paper read before the New York Academy of Medicine, that he had cured patients suffering from tabes dorsalis by treating various abnormalities that he had found in their urethras. Although some American physicians hailed Denslow's "cure" as a major advance in the treatment of tabetic patients, other physicians denounced his treatments as being worthless or, at best, providing minimal and transient symptomatic benefits. This contribution presents the highlights of Denslow's personal life and professional career. It also describes his urologic treatment of tabes dorsalis and the controversy that surrounded it.

Frailty as predictor of complications in patients undergoing percutaneous nephrolithotomy (PCNL).

INTRODUCTION & OBJECTIVE: Surgical complications are difficult to predict, despite existing tools. Frailty phenotype has shown promise estimating postoperative risk among the elderly. We evaluate the use of frailty as a predictive tool on patients undergoing percutaneous renal surgery. METHODS: Frailty was prospectively analyzed using the Hopkins Frailty Index, consisting of 5 components yielding an additive score: patients categorized not frail, intermediate, or severely frail. Primary outcomes were complications during admission and 30-day complication rate. Secondary outcomes included overall hospital length of stay (LOS) and discharge location. RESULTS: A total of 100 patients recruited, of whom five excluded as they did not need the procedure. A total of 95 patients analyzed; 69, 10, and 16 patients were not frail, intermediate, and severely frail, respectively. There were no differences in blood loss, number of dilations, presence of a staghorn calculus, laterality, or location of dilation. Severely frail patients were likely to be older and have a higher American Society of Anesthesiologists score and Charlson comorbidity index. Patients of intermediate or severe frailty were more likely to exhibit postoperative fevers, bacteremia, sepsis, and require ICU admissions (P < 0.05). Frail patients had a longer LOS (P < 0.001) and tended to require skilled assistance when discharge (p < 0.0001). CONCLUSIONS: Frailty assessment appears useful stratifying those at risk of extended hospitalization, septic complications, and need for assistance following percutaneous renal surgery. Risks of sepsis, bacteremia, and post-operative hemorrhage may be higher in frail individuals. Preoperative assessment of frailty phenotype may give insight into treatment decisions and represent a modifiable marker allowing future trials exploring the concept of "prehabilitation".

Novel Irrigation Protocol for Renal Pelvis Sterilization During Percutaneous Nephrolithotomy: A Pilot Study.

While percutaneous nephrolithotomy (PCNL) remains the treatment modality of choice for kidney stones larger than 2 cm, infectious complications are most common, ranging from 5% to 32%. We present here a novel technique for potentially improving collecting system sterility during PCNL and initial postoperative outcomes. Retrospective chart analysis data of our irrigation protocol were collected from our first 56 patients between February and July 2019. Traditional prone PCNL was performed in a standard manner using fluoroscopic guidance. Using a ureteral catheter that was placed cystoscopically, a renal pelvis urine culture was taken and subsequently 10 mL of betadine solution was instilled into the collecting system. Gentamicin in normal saline (80 mg/3 L) was utilized as the irrigant fluid for the first 6 L of irrigation. From this cohort, 57% patients were women and mean age was 60 ± 14 years. About 23% of patients were diabetic and 55% were hypertensive. Seventy percent of patients had stone burden >2 cm and no patients had stone burden <1 cm. Fifteen patients had positive urine cultures treated preoperatively, while four patients had contaminated cultures. All patients were treated with our antibiotic irrigation and betadine protocol regardless of preoperative cultures or antibiotics. Mean baseline creatinine level was 0.95 ± 0.41, with a mean change of 0.18 at postoperative day 1. Of the 15 (26%) of 56 patients with a systemic inflammatory response syndrome response (two of following four criteria: white blood cells <4 or >12; heart rate >90; hypothermia <96.8°F or hyperthermia >100.4°F; and respiratory rate >20), only six patients (11%) were febrile and two patients had positive blood cultures (3%). There were no adverse reactions to the betadine or antibiotic irrigation. We present here our initial experience of a new technique for renal pelvis sterilization and its safety and feasibility using intrarenal instillation of betadine and antibiotic irrigation. No Clinical Trial Registration number applicable.

Percutaneous kidney stone surgery and radiation exposure: A review.

During the past 3 decades, radiation exposure (RE) has increased drastically among patients undergoing percutaneous nephrolithotomy (PCNL), thus potentially causing new cases of cancer each year. The effective dose received by patients comes from pre- and post-operative computed tomography (CT) and intraoperative fluoroscopy (FL). We reviewed literature to find novel techniques and approaches that help to decrease RE of patients and personnel. We performed PubMed search using keywords percutaneous nephrolithotomy, intraoperative fluoroscopy, radiation exposure, imaging, percutaneous access, ultrasound, computed tomography, endoscopy, reconstruction, innovations, and augmented reality. Forty-four relevant articles were included in this review. As much as 20% of patients with first diagnosed urolithiasis exceed background RE level almost 17-fold. For diagnosing purposes using low-dose and ultra-low-dose CT, as well as low-dose dual energy scan protocols can be efficient ways to decrease RE while maintaining decent accuracy. Patients with urinary stones can be effectively monitored with digital tomosynthesis, ultrasound alone or ultrasound combined with plain film of the abdomen. Percutaneous access (PCA) into the kidney can be performed with reduced or even no RE, using novel PCA methods. REs from conventional imaging techniques during diagnosis and treatment increase probability of non-stochastic radiation effects. Urologists should be aware of protocols that decrease RE from CT and FL in diagnosis and management of urinary stones. Consideration of recently developed imaging modalities and PCA techniques will also aid in adherence to the "as low as reasonably achievable" principle.

Conservative Management of Liver Perforation During Percutaneous Nephrolithotomy: Case Couplet Presentation.

Percutaneous nephrolithotomy (PCNL) remains the recommended intervention for large kidney stones, major complications, although rare, are between 1% and 7%. Literature regarding liver injury during PCNL is sparse, and many incidences occur unnoticed. In general, most liver injuries can be treated conservatively when compared with other organ injury sustained during PCNL. Despite this, there is still significant potential for intraperitoneal bleeding as well as possible hemodynamic instability that may result secondary to the inadvertent access. Our team describes two cases of liver injury during PCNL with focus on presentation and injury management. Both cases were treated conservatively through close clinical monitoring and delayed removal of nephrostomy tube. Both liver injuries were diagnosed primarily through postprocedure axial CT imaging. In general, risk factors include supracostal access, particularly at or above the 11th rib, as well as hepatomegaly. Despite that liver injury is a rare complication of right-sided PCNL, outcomes can result in significant blood loss not diagnosed. We present in this study two instances of effective conservative management of liver injury after PCNL.

Management of Splenic Injury During Percutaneous Nephrolithotomy: Report of Two Cases.

Percutaneous nephrolithotomy (PCNL) has become the standard of care for the removal of kidney stones >2 cm. Major complications, although rare, are between 1% and 7%. Splenic injury during PCNL is rare and can often be managed conservatively, but has the potential to be devastating, necessitating the importance of early diagnosis. Our team describes two cases of splenic injury during PCNL with emphasis on diagnosis and management. Although both cases were managed conservatively through close monitoring and prolonged nephrostomy tube presence, one case had a concurrent pneumothorax. Both cases were diagnosed primarily through postprocedure CT imaging. Risk factors primarily include supracostal access and splenomegaly. Splenic injury is a rare complication that can often be managed conservatively; however, prompt recognition of injury is important. We present in this study two cases of conservative splenic injury management sustained during PCNL.

Management of Colon Perforation During Percutaneous Nephrolithotomy in Patients with Complex Anatomy: A Case Series.

Percutaneous nephrolithotomy (PCNL), first described in 1976, is the gold standard for the management of large kidney stones, with stone-free rates as high as 95% in contemporary literature. Colonic injuries during PCNL are a rare complication with an estimated incidence of 0.3%-0.5%. However, given the high morbidity incurred and the necessity of prompt operative intervention, it is imperative that practitioners have a low suspicion threshold for such injuries, particularly in those patients with altered or complex anatomy. This case series addresses peri- and postoperative outcomes of colon perforation during PCNL in patients with complex anatomy and reviews the technical challenges of surgery with potential methods to avoid injury in the future. Herein we review three instances of colonic injuries and their subsequent management to highlight both the presentation and the optimal management of these rare occurrences.

Endoscopic Management of Upper Urinary Tract Urothelial Carcinoma.

INTRODUCTION: Endoscopic management of upper tract urothelial carcinoma has become more popular over the last few decades as there has been an impetus for renal preservation in these patients. While radical nephroureterectomy has been the gold standard in treatment of this disease, ureteroscopic and percutaneous management has become a viable option for select patients. METHODS AND MATERIALS: The literature on endoscopic management of upper urinary tract tumors was explored. Different management methods are discussed, both from published literature and experience of the authors of this chapter. RESULTS: We review the indications, details of the procedure, and troubleshooting methods in the endoscopic management of upper tract urothelial carcinoma. Imperative indications as well as controversial indications are discussed. The role and efficacy of adjuvant intrarenal topical agents are examined as well as the protocol for administering these agents. Follow-up protocols are also reviewed. DISCUSSION: In select patients, endoscopic management with ureteroscopy and/or percutaneous resection of upper tract urothelial tumors is appropriate and can preserve renal function while obtaining comparable oncologic control compared with radical surgery.

Efficacy of Multi-Detector Computed Tomography for the Diagnosis of Medullary Sponge Kidney.

OBJECTIVE: To expand the diagnostic armamentarium for medullary sponge kidney (MSK), we evaluate the use of high-resolution multidetector computed tomography (MDCT) for MSK diagnosis and compare to the standard intravenous urography (IVU). Despite a significant prevalence amongst stone formers, diagnosis of this well described condition has declined. IVU, the gold standard in MSK diagnosis, has largely been replaced by CT, which has previously been shown unable to demonstrate signs of MSK. METHODS AND MATERIALS: Patients with known history of MSK based on IVU underwent limited MDCT urogram. Control group patients, without MSK, also had MDCT urograms performed for other clinically indicated conditions. Studies were scored by board-certified radiologists on a 0-2 scale based on the likelihood of MSK. IVU studies, when available, were similarly graded. RESULTS: MDCT was diagnostic of MSK in 9 out of the 10 patients with known history of MSK. No false positives were present in our series. The one case of MSK not detected on MDCT was graded as a "1" on its respective IVU. Sensitivity and specificity were 90 and 100%, respectively, when compared with IVU. CONCLUSION: Concordance with IVU findings, despite a small reduction in sensitivity, indicates MDCT to be a suitable, and more readily available replacement for IVU in the diagnosis of MSK.

Incorporation of the fluoroless C-Arm Trainer at the American Urological Association hands on training percutaneous renal access.

OBJECTIVES: To assess for usefulness and validity evidence for incorporating the C-Arm Trainer (CAT) simulator into the annual AUA hands on course for training percutaneous nephrolithotomy (PCNL). MATERIALS AND METHODS: The course started with a didactic session followed by four stations for training the "bull's eye" technique using the CAT simulator. Each station included a pre-test, 30-min practice on the simulator, and post-test. All participants were assessed using a 4-item checklist. All participants were asked to fill in a qualitative self-assessment questionnaire after the pre- and the post-test, and respond to a course evaluation questionnaire and post-course survey. RESULTS: A total of 38 physicians, who attended the hands on course, voluntarily participated in the study. Only 21.1% had previous practice on PCNL simulators. Compared with the results of the checklist total score and the qualitative self-assessment questionnaire scores after the pre-test, there was significant improvement in the checklist total score (p < 0.001), temporal demands (p = 0.003), situational stress (p = 0.003, and performance (0.003) after the post-test. A total of 14 (36%) participants responded to the course evaluation questionnaire, 50% evaluated the course as excellent, 28.6% as very good, and 21.4% as good. Unfortunately, only five (13%) participants responded to the post-course survey, 4/5 implemented the new competencies and knowledge into their practice, and 3/5 have attempted to obtain fluoroscopic guided PCA without assistance. CONCLUSION: The CAT simulator was considered useful for training the percutaneous renal access procedure. There was significant improvement in the qualitative and quantitative assessment parameters after the post-test compared with the pre-test.

Renal functional outcomes are not adversely affected by selective angioembolization following percutaneous nephrolithotomy.

OBJECTIVE: Selective angioembolization (SAE) effectively diagnoses and treats iatrogenic vascular complications following percutaneous nephrolithotomy (PCNL). METHODS: We retrospectively reviewed 1329 consecutive PCNLs and identified patients who underwent SAE following PCNL with at least 12-month follow-up. Estimated glomerular filtration rate (eGFR) was calculated for all patients preoperatively, postoperatively and at last follow-up. A 1:2 matched cohort analysis was performed. RESULTS: Twenty-three patients underwent SAE and matched to 46 controls. There was no statistically significant difference in preoperative, postoperative, and follow-up eGFR when comparing patients who underwent SAE and those with an uneventful course. CONCLUSION: Long-term eGFR is comparable in patients who undergo uncomplicated PCNL and those requiring SAE.

Prediction of surgical complications in the elderly: Can we improve outcomes?

As the number of Americans aged 65 years and older continues to rise, there is projected to be a corresponding increase in demand for major surgeries within this population. Consequently, it is important to utilize accurate preoperative risk stratification techniques that are applicable to elderly individuals. Currently, commonly used preoperative risk assessments are subjective and often do not account for elderly-specific syndromes that may pose a hazard for geriatric patients if not addressed. Failure to accurately risk-stratify these patients may increase the risk of postoperative complications, morbidity, and mortality. Therefore, we aimed to identify and discuss the more objective and better-validated measurements indicative of poor surgical outcomes in the elderly with special focus on frailty, patient optimization, functional status, and cognitive ability.

A Randomized Controlled Comparison of Nephrostomy Drainage vs Ureteral Stent Following Percutaneous Nephrolithotomy Using the Wisconsin StoneQOL.

OBJECTIVE: We compared postoperative outcomes and quality of life (QoL) between patients who received a nephrostomy tube vs a ureteral stent following percutaneous nephrolithotomy (PCNL) in a prospective, double-blind, randomized manner. MATERIALS AND METHODS: Between September 2015 and March 2016, we randomized 30 patients undergoing PCNL to receive nephrostomy drainage (Group 1: 8F or 10F) or Double-J ureteral stent (Group 2) at conclusion of surgery. Nephrostomy tubes were removed within 48 hours (before discharge) and ureteral stents were removed at least 2 weeks after surgery. Patients' QoL was assessed with the Wisconsin StoneQOL questionnaire preoperatively and then 7 to 10 days and 30 days following surgery. Inclusion criteria included an uncomplicated procedure, normal preoperative renal function, and clinically insignificant residual stone fragments on postoperative imaging. We calculated the preoperative and postoperative QoL score difference between the two groups. We also evaluated perioperative characteristics, inpatient analgesic requirements, length of stay (LOS), and postsurgical complications. OUTCOME: Patient characteristics between Groups 1 and 2 were comparable with similar age (58.3 vs 54.7, p = 0.534), gender ratio, and stone burden (276.6 mm2 vs 259 mm2, p = 0.84) and composition. There was no significant difference between perioperative outcomes, including stone-free rate (93.3% vs 86.7%), operative times (125.7 minutes vs 115 minutes, p = 0.29), estimated blood loss (103.3 mL vs 100.7 mL, p = 0.9), LOS (3.2 days vs 1.9 days, p = 0.1), and complications (2 in each group). Inpatient analgesic requirements were also the same (both 21.1 mg, p = 1.0). Assessment of QoL using the Wisconsin StoneQOL questionnaire showed significant differences between preoperative and postoperative health-related QoL in 18 of the 28-question instrument at 7 to 10 days. Patients in Group 2 had significantly worse QoL change and a multitude of negative responses on the StoneQOL assessment, not only those commonly associated with stent irritation. Eighty percent of participants in Group 2 also attributed their complaints to having a stent placed. Both groups had similar QoL status at 30 days after surgery. CONCLUSION: Despite the literature advocating "tubeless" PCNL with ureteral stent placement at conclusion of surgery, our randomized prospective study shows that QoL is significantly worse with stent placement than with temporary nephrostomy drainage in the immediate aftermath following PCNL, using a validated QoL assessment instrument specific for nephrolithiasis.

A Case for Nephron Sparing Surgery in the Management of Upper Tract Urothelial Carcinoma.

Upper tract urothelial carcinoma (UTUC) is rare and its management presents many challenges. Outside of distal ureterectomy for select cases, management has been primarily radical nephroureterectomy. Endoscopic nephron sparing management (NSM) is recognized to have some role in UTUC treatment; however, it is yet to gain firm footing in the treatment algorithm. In this review, we discuss the benefits of NSM with regards to oncologic outcomes, renal function preservation, and cost savings. Finally, we propose recognition of endoscopic NSM as a first-line treatment in selected patients with low risk disease.

Can Activities of Daily Living Predict Complications following Percutaneous Nephrolithotomy?

PURPOSE: Activities of daily living provide information about the functional status of an individual and can predict postoperative complications after general and oncological surgery. However, they have rarely been applied to urology. We evaluated whether deficits in activities of daily living could predict complications after percutaneous nephrolithotomy and how this compares with the Charlson comorbidity index and the ASA(®) (American Society of Anesthesiologists(®)) classification. MATERIALS AND METHODS: We retrospectively reviewed the records of all patients who underwent percutaneous nephrolithotomy between March 2013 and March 2014. Those with complete assessment of activities of daily living were included in analysis. Perioperative outcomes, complications and hospital length of stay were examined according to the degree of deficits in daily living activities. RESULTS: Overall 176 patients underwent a total of 192 percutaneous nephrolithotomies. Deficits in activities of daily living were seen in 16% of patients, including minor in 9% and major in 7%. Complications developed more frequently in those with vs without deficits in daily living activities (53% vs 31%, p = 0.029) and length of stay was longer (2.0 vs 4.5 days, p = 0.005). On multivariate logistic regression activities of daily living were an independent predictor of complications (OR 1.11, p = 0.01) but ASA classification and Charlson comorbidity index were not. CONCLUSIONS: Activities of daily living are easily evaluated prior to surgery. They independently predict complications following percutaneous nephrolithotomy better than the Charlson comorbidity index or the ASA classification. Preoperative assessment of daily living activities can help risk stratify patients and may inform treatment decisions.

Percutaneous nephrolithotomy in super obese patients (body mass index ≥ 50 kg/m²): overcoming the challenges.

OBJECTIVE: To analyse our experience with and the outcomes and lessons learned from percutaneous nephrolithotomy (PCNL) in the super obese (body mass index [BMI] ≥50 kg/m(2) ). PATIENTS AND METHODS: In this institutional review board approved study we retrospectively reviewed our PCNL database between July 2011 and September 2014 and identified all patients with a BMI ≥ 50 kg/m(2) . Patient demographics, peri-operative outcomes and complications were determined. Additionally, we identified a number of special PCNL considerations in the super obese that can maximize safe outcomes. RESULTS: A total of 21 PCNL procedures performed on 17 super obese patients were identified. The mean patient age was 54.8 years, the mean BMI was 57.2 kg/m(2) and the mean stone area was 1 037 mm(2) . Full staghorn stones were observed in six patients and partial staghorns in four patients. The mean operating time was 106 min and the mean haemoglobin decrease was 1.2 g/dL. The overall stone-free rate was 87%. There were four total complications: two Clavien grade II, one Clavien IIIb and one Clavien IVb. We identified several special considerations for safely preforming PCNL in the suber obese, including using extra-long nephroscopes and graspers, using custom-cut extra long access sheaths with suture 'tails' secured to easily retrieve the sheath, choosing the shortest possible access tract, readily employing flexible nephroscopes, placing nephroureteral tubes rather than nephrostomy tubes postoperatively, and meticulous patient positioning and padding. CONCLUSION: With appropriate peri-operative considerations and planning, PCNL is feasible and safe in the super obese. Stone clearance was similar to that reported in previous PCNL series in the morbidly obese, and is achievable with few complications.

Stenting for malignant ureteral obstruction: Tandem, metal or metal-mesh stents.

Extrinsic malignant compression of the ureter is not uncommon, often refractory to decompression with conventional polymeric ureteral stents, and frequently associated with limited survival. Alternative options for decompression include tandem ureteral stents, metallic stents and metal-mesh stents, though the preferred method remains controversial. We reviewed and updated our outcomes with tandem ureteral stents for malignant ureteral obstruction, and carried out a PubMed search using the terms "malignant ureteral obstruction," "tandem ureteral stents," "ipsilateral ureteral stents," "metal ureteral stent," "resonance stent," "silhouette stent" and "metal mesh stent." A comprehensive review of the literature and summary of outcomes is provided. The majority of studies encountered were retrospective with small sample sizes. The evidence is most robust for metal stents, whereas only limited data exists for tandem or metal-mesh stents. Metal and metal-mesh stents are considerably more expensive than tandem stenting, but the potential for less frequent stent exchanges makes them possibly cost-effective over time. Urinary tract infections have been associated with all stent types. A wide range of failure rates has been published for all types of stents, limiting direct comparison. Metal and metal-mesh stents show a high incidence of stent colic, migration and encrustation, whereas tandem stents appear to produce symptoms equivalent to single stents. Comparison is difficult given the limited evidence and heterogeneity of patients with malignant ureteral obstruction. It is clear that prospective, randomized studies are necessary to effectively scrutinize conventional, tandem, metallic ureteral and metal-mesh stents for their use in malignant ureteral obstruction.