Ureteral Stent Encrustation: Epidemiology, Pathophysiology, Management and Current Technology.

PURPOSE: Encrustation is a common phenomenon that can occur following placement of a ureteral stent into the urinary tract, and it can lead to serious complications. The following review addresses the mechanism of encrustation, the management of these stents and the newest technology developed to mitigate this issue. MATERIALS AND METHODS: We performed a comprehensive literature search on stent encrustation including peer-reviewed publications, public product listings, and material on current and future stent technology. RESULTS: The mechanism of encrustation is complex and multifaceted, including dwell time, patient specific risk factors, conditioning film formation, biofilm formation and mineral deposition. Several technological developments in stent materials and coatings may have a role in reducing the risk of stent encrustation. It is important to identify the extent of stent encrustation and plan treatment strategies accordingly. We propose a novel treatment algorithm for the management encrusted ureteral stents. CONCLUSIONS: The ubiquity of ureteral stents in urology practice mandates updated knowledge about the prevention of stent encrustation, identification of high risk patients and preparedness for removal using multimodal techniques.

Tamsulosin or Silodosin Adjuvant Treatment Is Ineffective in Improving Shockwave Lithotripsy Outcome: A Short-Term Follow-Up Randomized, Placebo-Controlled Study.

INTRODUCTION: The role of α-blockers after shockwave lithotripsy (SWL) is controversial. The aim of our study was to evaluate the effect of tamsulosin and silodosin after SWL for kidney stones. METHODS: From 2012 onward, a consecutive series of patients undergoing SWL were prospectively enrolled and randomized by closed envelopes in three groups receiving tamsulosin 0.4 mg (A), silodosin 8 mg (B), and placebo (C) daily for 21 days after SWL. Anthropometrics, stone size, and location were recorded before SWL. Visual analogue scale (VAS) score was collected at 6, 12, and 24 hours after treatment to evaluate patients' discomfort. Stone-free rate was assessed 1 and 3 weeks postoperatively. Complications and medical treatment-related adverse events (AEs) were recorded. Differences in VAS score, stone-free rate, and complications were compared among the groups. RESULTS: Overall, 60 patients were enrolled. Mean stone sizes were 10.28 ± 2.46 mm, 10.45 ± 1.73 mm, and 9.23 ± 2.04 mm in groups A, B, and C, respectively (p = 0.474). There was no significant difference between the three groups with regard to stone location. Comparable energy was used to treat patients from the three groups. The overall 3-week stone-free rate was 53%: 58% in the tamsulosin group, 47% in the silodosin group, and 55% in the placebo group (p = 0.399). No significant differences were observed in the VAS scores reported by the groups at 6 hours (p = 1.254), 12 hours (p = 0.075), and 24 hours (p = 0.490). Overall, 12 complications were reported: 11 patients (7 in group C and 4 in group B) needed analgesics for colic, and 1 patient (group B) was surgically treated for Steinstrasse. Tamsulosin was superior to placebo (p = 0.008) and silodosin (p = 0.021) in preventing complications; no difference between silodosin and placebo (p = 0.629) was noted. CONCLUSIONS: Tamsulosin and silodosin are ineffective in increasing stone-free rate as well as early patients' discomfort after extracorporeal lithotripsy.

Risk factors for formation of steinstrasse after extracorporeal shock wave lithotripsy for pediatric renal calculi: a multivariate analysis model.

OBJECTIVES: To define various stone, renal and therapy factors that could affect steinstrasse (SS) formation after extracorporeal shock wave lithotripsy (SWL) for pediatric kidney stones. Thus, SS could be anticipated and prophylactically avoided METHODS: From January 1999 through December 2012, 317 children underwent SWL with Dornier Lithotripter S for the treatment of renal stones. Univariate and multivariate statistical analyses of patients, stones and therapy characteristics in relation to the incidence of SS were performed to detect the factors that had a significant impact on SS formation. RESULTS: The overall incidence of SS was 8.5%. The steinstrasse was in the pelvic ureter in 74.1% of the cases, lumbar ureter in 18.5% and iliac ureter in 7.4%. Steinstrasse incidence significantly correlated with stone size, site and age of child. Steinstrasse was more common with increasing stone length and stones located in renal pelvis or upper calyx with the age below 4 years. A statistical model was constructed to estimate the risk of steinstrasse formation accurately. The equation for logistic regression is Z = -4.758 + B for age + B for size stone X length in mm + B for stone site. CONCLUSIONS: The stone size, site and age are the most important risk factors responsible for SS formation in children. Our regression analysis model can help with prospective identification of children who will be at risk of SS formation. Those children at high risk of SS formation should be closely monitored or treated by endoscopic maneuvers from the start.

Estudo da ocorrência de litíase renal e ureteral em gatos com doença renal crônica / Study of nephrolithiasis and ureterolithiasis in cats with chronic kidney disease

Investigou-se a ocorrência de nefrolitíase e/ou ureterolitíase em 72 gatos portadores de doença renal crônica (DRC), classificados predominantemente no estágio II, segundo os critérios designados pela IRIS - International Renal Interest Society. Destes pacientes, 47 (65,27por cento) apresentaram litíase renal e ou ureteral. Não houve diferença estatística entre o grupo de estudo (DRC com cálculo) e o grupo controle (DRC sem cálculo) em relação à idade (p=0,274). Apesar disso, os pacientes portadores de nefrolitíase e/ou ureterolitíase apresentaram maiores indícios de lesão renal, caracterizados por diferenças estatisticamente relevantes da densidade urinária (p=0,013) e pelo menor tamanho dos rins direito (p=0,009) e esquerdo (p=0,048). Encontrou-se similaridade entre os grupos em relação a outros parâmetros, tais como as concentrações plasmáticas de cálcio total, cálcio ionizado, fósforo, sódio, potássio e paratormônio intacto (PTHi). Os valores das concentrações séricas de ureia e bicarbonato diferiram entre os grupos, com valores de p=0,039 e p=0,037, respectivamente. Além disso, foi mensurada a pressão arterial, que se manteve inalterada na comparação entre o grupo de estudo e o grupo controle. Os resultados obtidos reforçam a necessidade de acompanhamento ultrassonográfico de todos os pacientes portadores de DRC, mesmo daqueles assintomáticos ou em estágios iniciais da doença.

Nephrolithiasis and/or ureterolithiasis were investigated by means of ultrasonography in 72 cats with chronic kidney disease (CKD), predominantly classified in stage II, according to IRIS - International Renal Interest Society criteria. Of these patients, 47 (65.27 percent) had nephrolithiasis and/or ureterolithiasis. There was no statistical difference between the study group (CKD with calculi) and control group (CKD without calculi) regarding age (p=0.274). Nevertheless, patients with nephrolithiasis and/or ureterolithiasis had greater evidence of renal injury, characterized by statistically significant differences in the urinary density (p=0.013) and the smaller size of the right kidney (p=0.009) and left kidney (p=0.048), measured in the longitudinal plane. There were no difference between groups in the other parameters investigated such as plasmatic total calcium, ionized calcium, phosphorus, sodium, potassium and intact parathyroid hormone concentrations. The values of serum urea and bicarbonate differ between groups with p=0.039 and p=0.037, respectively. Furthermore, arterial blood pressure was measured, remaining unchanged between the groups. One can conclude that nephrolithiasis and/or ureterolithiasis are common findings in cats with CKD and these results reinforce the need to perform image investigation in cats with CKD even in the asymptomatic ones, or those in the early stages of the disease.

Unusual presentation of bilateral ureteroceles with ureterolithiasis in a patient after robotic prostatectomy.

We present a unique case of incidentally discovered symptomatic, stone-laden ureteroceles after robotic prostatectomy at a high-volume institution. The 2-month postoperative timeline to presentation and laser unroofing management strategy for bilateral ureteroceles after robotic prostatectomy are described.

Retrograde ureteral access after cross-trigonal ureteral reimplantation: A straightforward technique.

PURPOSE: Retrograde ureteral access after cross-trigonal ureteral reimplantation can be challenging. We present our experience with percutaneous retrograde ureteral catheterization, status post cross-trigonal ureteral reimplantation. MATERIALS AND METHODS: We evaluated all patients who underwent attempted percutaneous retrograde ureteral catheterization after cross-trigonal ureteral reimplantation. All clinical data, radiographic images and operative reports were reviewed. Ureteral access was obtained by percutaneously entering the bladder with an intravenous needle/catheter under cystoscopic guidance. The needle was then removed leaving the catheter in place. The ureteral orifice was then accessed through the intravenous catheter by a ureteral access wire and/or ureteral catheter under cystoscopic guidance. RESULTS: From 1978 to 2008, 13 patients (11 boys and 2 girls) with a history of cross-trigonal ureteral reimplantation underwent percutaneous retrograde ureteral catheterization. The procedure was unilateral in 12 patients and bilateral in one. Indications for the procedure included: retrograde pyelography and double-J stent insertion for ureteropelvic junction or ureterovesical junction obstruction (10); removal of migrated stent (2); and treatment of a ureteral stone (1). The procedure was performed successfully in all patients and without complications. CONCLUSIONS: Percutaneous retrograde ureteral catheterization is a safe, straightforward, and effective modality for obtaining retrograde ureteral access in children, status post cross-trigonal ureteral reimplantation.

Retrocaval ureter with stone in the retrocaval segment of the ureter.

Retrocaval ureter is abnormal looping of the proximal ureter behind the inferior vena cava. The aberrant anatomy results in the compression of the ureter causing hydronephrosis. This is a very infrequent cause of hydronephrosis in children. Association of retrocaval ureter with a stone in the looping segment of the ureter is extremely rare. We report one such pediatric case which was diagnosed preoperatively with a review of pediatric-only cases reported in last 5 years.

[Single session cystolitholapaxy and PCNL for encrusted DJ stent with large associated stone burden]. / Stent DJ calcifico con litiasi multipla calicopielica e vescicale associata: trattamento con litotrissia vescicale e PCNL in una singola seduta.

INTRODUCTION: Ureteral stent use is commonplace in urology to prevent or relieve ureteral obstruction. If ureteral stents are neglected, they can cause severe morbidity due to migration, occlusion, encrustation, breakage, stone formation, and even death, due to life-threatening urosepsis or complications related to operative intervention. Extracorporeal shockwave lithotripsy, ureterorenoscopy, electrohydraulic lithotripsy, laser lithotripsy, and percutaneous nephrolitholapaxy (PCNL) have been reported for forgotten ureteral stent management, but currently there are no guidelines for this challenging situation and only few algorithms have been introduced by some studies. METHODS: We present a case of a man presenting with an encrusted left double J (DJ) stent, inserted two years before, and bulky radiolucent lithiasis at both ends of the stent. The patient was studied with intravenous pyelogram and non contrast-enhanced computed tomography, and then treated with cystolithotripsy and PCNL in a single session. RESULTS: Complete clearance of the stones was obtained and the DJ stent was removed without breaking from the percutaneous access. CONCLUSIONS: Neglected stents still represent a challenge in urology: while endourology remains the best option for treatment, the management of ureteral stents should be based on follow-up and prevention, using for example a computerized warning and stent retrieval software system.

Litiasis ureteral en paciente portadora de derivación urinaria tipo Bricker / Ureteral lithiasis in a patient with Bricker type urine diversion

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