Stent-Change Therapy in Advanced Malignancies with Ureteral Obstruction

Impact of long-term indwelling JJ stent on renal volume and renal function

BACKGROUND

Data is lacking about long-term impact of JJ stents (JJst) on renal parenchyma. The aim of the study was to assess the evolution of renal parenchyma in patients with JJst indwelling for more than two years, and to find predictive factors for the development of renal atrophy.

METHODS

Consecutive patients with JJst indwelled for more than 24 months, with a history of cancer, were retrospectively included. Replacements of JJst were scheduled every six months, or earlier in case of premature obstruction. Patient characteristics at the time of insertion of JJst, history of indwelling JJst and most recent data (serum creatinine, cancer status, definite JJst removal, renal volume (RV) with3D software) were recorded.

RESULTS

With a median follow-up of 4 years, 73 patients were included. The indication of JJst insertion was mostly external compression (65.8%). CT scans were available to assess RV evolution in 66 patients (90.4%). Median shrinkage of RV was higher when JJ stenting was unilateral versus bilateral: -40% (-63; -15) versus -16% (-36; -3), P<0.001. The duration of indwelling JJst was the only statistically significative predictive factor of renal shrinkage in multivariate analysis (OR [CI 95%]: 1.35 [1.10-1.66] P=0.004). Median relative change from baseline in eGFR was -22% (-45%; -5%.). No statistically significant predictive factors of eGFR evolution were found in univariate and multivariate analysis.

CONCLUSIONS

Unilateral JJst for more than 2 years was associated with a significant shrinkage of renal parenchyma, especially since the duration of the indwelling stent was long.

It is Possible to Reduce Ureteral Stent Clogging and Stent-Related Symptoms to Soothe the Pain of the Patient: A Case Report

Introduction

Ureteral stent obstruction hinders the management of malignant diseases. Adequate stent insertion through an obstructed ureter does not necessarily guarantee renal decompression and stent-related symptoms adversely affect patient comfort. There are two major problems associated with ureteral stents: obstruction and intolerance to the stents.

Case Presentation

A 45-year-old woman was treated for cervical cancer with metastatic lymph nodes and ureteral obstruction with chemotherapy, radiotherapy, immunotherapy, and bilateral retrograde stenting. After recurrent stent obstruction, stent replacement was attempted more than 18 times over two years. In addition, stent-related symptoms adversely affected patient comfort. The patient was finally fitted with Superglide 8-French reinforced ureteral stents. Their replacement every six months was viewed by the patient as a relief compared to the all too frequent replacement of the previous stents. Moreover, the customized changes in the shape of Superglide stents improved patient comfort.

Discussion

Recent publications tend to indicate that large-lumen ureteral stents are most likely to remain permeable over time. Various modifications of the bladder or endo-ureteral part of double-pigtail stents have been increasingly reported, with the aim of improving their tolerance while maintaining effective drainage.

Conclusion

Adaptation of the internal lumen and shape of stents to the characteristics of the tumor and patient measurements appears to be important for increasing the drainage and tolerance of ureteral stents. The top priority for future ureteral stents suitable for malignant diseases should be to integrate these characteristics based on state-of-the-art data.

Acute kidney injury due to bilateral malignant ureteral obstruction: Is there an optimal mode of drainage?

There is a well-known relationship between malignancy and impairment of kidney functions, either in the form of acute kidney injury or chronic kidney disease. In the former, however, bilateral malignant ureteral obstruction is a surgically correctable factor of this complex pathology. It warrants urgent drainage of the kidneys in emergency settings. However, there are multiple controversies and debates about the optimal mode of drainage of the bilaterally obstructed kidneys in these patients. This review addressed most of the concerns and provided a comprehensive presentation of this topic from the recent literature. Also, we provided different perspectives on the management of the bilateral obstructed kidneys due to malignancy. Despite the frequent trials for improving the success rates and functions of ureteral stents, placement of a percutaneous nephrostomy tube remains the most recommended tool of drainage due to bilateral ureteral obstruction, especially in patients with advanced malignancy. However, the disturbance of the quality of life of those patients remains a major unresolved concern. Beside the unfavorable prognostic potential of the underlying malignancy and the various risk stratification models that have been proposed, the response of the kidney to initial drainage can be anticipated and evaluated by multiple renal prognostic factors, including increased urine output, serum creatinine trajectory, and time-to-nadir serum creatinine after drainage.

Analysis of Ureteral Tumour Stents for Malignant Ureteral Obstruction: Towards Reshaping an Optimal Stent

Introduction

Ureteral obstruction hinders the management of malignant diseases. Adequate stent placement does not necessarily guarantee renal decompression. The stent stiffness may play a major role to maintain patency. We carried out the present study in order to evaluate drainage efficiency by using stents with distinctive degrees of stiffness and to identify the physical factors that could prevent obstruction of the stent in patients with malignant ureteral obstruction (MUO).

Materials and Methods

We performed an analysis of 150 patients with MUO drainage at a single institution from June 2009 to June 2019. A progressive choice of stents was shaped to overcome each failure by focusing on the criterion of increasingly stiff stents.

Results

During the study period, 556 ureteral stent procedures (USP) were analysed separately. The stent failure with obstruction occurred in 23.0% (128/556) of USP at a mean of 4.4±3.6 months and depended on the type of stent. Stent failure occurred in 34.2% (70/205) of Vortek^® stents, in 42.9% (15/35) of Urosoft stents, in 15.4% (39/254) of Superglide or ureteral catheters and in 6.5% (4/62) of tandem stents. No significant differences were found between Vortek^® and Urosoft stents regarding stent failures, but there were significant differences between Superglide or Tandem stents and Vortek^® or Urosoft stents (p<10⁻⁷). The study demonstrated that ureteral stent obstruction significantly decreased with a larger lumen or a stiffer stent (p<10⁻⁷).

Conclusion

In the present study, Superglide and tandem stents were the best stents against stent failure, and the lumen and the stiffness of the stent have been shown to be critical factors in controlling patency. The results suggest that the lumen seems more important than the stiffness, and the stiffness would be the only means of keeping the lumen intact. Future stents for MUO should integrate the importance of the lumen of the stent.

Metal stent for the ureteral stricture after surgery and/or radiation treatment for malignancy

BACKGROUND

To assess the efficacy and safety of self-expanding metal ureteral stent for the stricture following surgery and/or radiation for malignancy.

METHODS

We performed 36 metal ureteral stent insertion procedures (32 patients) between May 2019 and June 2020. The main inclusion criterion was the patients with ureteral stricture due to surgery and/or radiation treatment for malignancy. The diagnosis of stricture was ascertained by history and radiographic imaging. The etiologies underlying the strictures were: surgery and/or radiation therapy for cervical and rectal cancer, surgery for ovarian cancer. The primary outcome was the stent patency rate, and the secondary outcomes were the postoperative complications and glomerular filtration rate (GFR). Stent patency was defined as stent in situ without evident migration, unanticipated stent exchange or recurrent ureteral obstruction. Cost analysis was calculated from stent cost, anesthesia cost and operating room fee.

RESULTS

The pre-metallic stent GFR was 22.53 ± 6.55 mL/min/1.73 m². Eight patients were on double-J stents before insertion of metallic stents. The total annual cost of per patient in our study was $10,600.2 US dollars (range $9394.4-$33,527.4 US dollars). During a median follow-up time of 16 months (range 8-21 months), 27 cases (31 sides, 84%) remained stent patency. Twelve patients died from their primary malignancy carrying a patency stent. Stent migration was observed in 4 patients within 10 months after insertion. Ectopic stents were endoscopically removed and replaced successfully. Three stents were occluded, and no encrustation was seen in our study. Three and four patients had postoperative fever and gross hematuria, respectively. Infection was observed in 2 cases, mandating antibiotics therapy. In addition, postoperative volume of hydronephrosis postoperatively was significantly reduced compared with preoperation (54.18 ± 15.42 vs 23.92 ± 8.3, P = 0.019). However, no statistically significant differences regarding GFR, creatinine levels, blood urea nitrogen and hemoglobin existed between preoperation and last follow-up.

CONCLUSIONS

The current study demonstrated that metal ureteral stent is effective and safe in the treatment of stricture following surgery and/or radiation therapy for malignant cancer. Patients hydronephrosis could be improved by the stent placement.

10-Year Experience with Reinforced Ureteral Stents for Malignant Ureteral Obstruction

Introduction

Malignant ureteral obstruction (MUO) hinders the management of malignant diseases. Indwelling stent is a common method to release renal obstruction, but stent failure with obstruction is frequent. The studies conclude that stent obstruction divides survival by 2 or even 4. We carried out the present study in order to evaluate drainage efficiency and overall survival by using stents with distinctive degrees of stiffness.

Materials and Methods

We performed an analysis of 156 patients with MUO drainage at a single institution from June 2009 to June 2019.

Results

Of the 156 patients, 128 (82.1%) died with a mean survival time of 15.3 ± 14.4 months after the first ureteral stent procedure (USP). In order to study stent failure and overall survival, the patients were divided into 3 groups. Group 1 with patients died soon after only one USP (n=37). Group 2 with patients had more than one USP and no obstruction (n=41). Patients in Group 3 had more than one USP and at least one stent obstruction (n=62). During the study period, 556 USPs were analysed separately. The stent failure with obstruction occurred in 23.0% (128/556) of USP at a mean of 4.4 ± 3.6 months. In case of stent failure, a progressive choice of stents was shaped to overcome each failure by focusing on the criterion of increasingly stiff stents. Patients in Group 1 died soon at mean of 4.9 ± 4.8 months. The mean survival time of patients in Groups 2 and 3 were, respectively, 19.4 ± 11.2 and 21.5 ± 16.3 months (P = 0.19).

Conclusion

MUO is a serious disease but this study is the first to prevent survival rate from falling by choosing the stent stiffness suitable for the patient. The active detection of stent failure has been shown to be essential for preserving survival.

Subcutaneous nephrovesical bypass in a patient with advanced prostate cancer

In the presence of hydronephrosis, as a result of ureteral malignant invasion, advanced pelvic tumor or retroperitoneal fibrosis, we most often perform a double J stent or percutaneous nephrostomy. In the search for a better quality of life for our patients in recent years in urological practice is increasingly becoming the use of subcutaneous nephrovesical bypass due to its proven safety, effectiveness and minimal invasiveness.

A novel risk classification score for malignant ureteral obstruction: a multicenter prospective validation study

Emergence of malignant ureteral obstruction (MUO) has been reported as a sign of poor prognosis; however, the distribution of survival time in patients with MUO is considerably wide, and no risk classification score has been constructed. To evaluate whether a novel risk classification score for overall survival that we previously developed, is effective in a large cohort. Investigator-initiated, prospective, multicenter diagnostic/prognostic study was conducted. Patients with MUO were divided into three risk groups based on the score calculated using four prognostic factors (PLaCT: Primary site, Laterality, serum Creatinine level, and Treatment for primary site) at the first visit, and prospective follow-up was performed. Overall survival and ureteral stent failure-free survival of each risk group were compared. In total, 300 patients with 21 different primary sites were enrolled. The numbers of patients in good, intermediate, and poor risk groups were 105, 106, and 89, respectively. Median survival times of patients in good, intermediate, and poor risk groups were 406, 221, and 77 days, respectively (P < 0.0001). In 217 patients with ureteral stenting, median ureteral stent failure-free survival times of good, intermediate, and poor risk groups were 385, 183, and 57 days, respectively (P < 0.0001). Limitations include the limited ethnicity and the extended duration of study enrollment. The novel PLaCT risk classification score could divide MUO patients into three risk groups with distinct survival times and ureteral stent patencies. This score will aid in establishing prognosis and treatment strategy for all physicians engaged in cancer treatment.

Hydronephrosis in patients with cervical cancer is an indicator of poor outcome: A nationwide population-based retrospective cohort study

Cervical cancer is a common malignancy in women. The presence of hydronephrosis in patients with cervical cancer can be a challenging clinical problem. The appropriate management of these patients and the prediction of their outcomes are concerns among gynecologists, urologists, medical oncologists, radiation oncologists, and nephrologists. We enrolled a total of 2225 patients with cervical cancer over a 12-year period from the nationwide database of Taiwan's National Health Insurance Bureau. Among them, 445 patients had concomitant hydronephrosis. The remaining 1780 patients without hydronephrosis were randomly enrolled as a control group for the analysis of associated factors. The results indicated that the proportions of patients with hypertension, chronic kidney disease, and diabetes were significantly higher in the hydronephrosis group. The hydronephrosis group showed a higher all-cause mortality than the non-hydronephrosis group (adjusted hazard ratio 3.05, 95% confidence interval 2.24-4.15, P < .001). The rates of nephrectomy and stone disease were also significantly higher in the hydronephrosis group. A higher percentage of other cancers was also observed in the hydronephrosis group than in the non-hydronephrosis group (12.36% vs 8.99%, respectively). This study shows that cervical cancer with hydronephrosis may have a higher morbidity and mortality than cervical cancer without hydronephrosis. Other factors such as human papilloma virus vaccination, smoking, and cancer staging need to be further studied.

Use of metallic and polymeric ureteral stents in malignant ureteral obstruction

Background

Malignant ureteral obstruction (MUO) is often caused by advanced intra‐abdominal cancers. Effective management must be attempted, but the treatment policy is unclear. Metallic ureteral stents are one of the latest options in managing MUO. Metallic ureteral stents are superior to traditional polyurethane stents. The present study retrospectively reviewed our four institutions’ experiences with treating MUO using metallic ureteral stent.

Methods

A total of 45 patients who required metallic ureteral stent placement for MUO at Yokohama City University Medical Center (Yokohama, JAPAN) between January 2014 and May 2016 were analyzed. We defined stent failure as having to change the ureteral stent before the scheduled ureteral stent exchange time or having to perform percutaneous nephrostomy (PCN). Complications were defined as an unscheduled hospital visit or hospitalization caused by incompatibility, infection, and pain of the metallic ureteral stent, etc., unrelated to the primary disease. We compared stent failure and the overall survival (OS) between metallic and polymeric ureteral stents. To evaluate the workload of the medical staff, we used the NASA Task Load Index (NASA‐TLX) in a total of 11 urologists.

Results

During the observation period, 8 (17.8%) patients in the metallic ureteral stent group and 10 (27.8%) in the control group developed stent failure. Complications were noted in 14 (31.1%) patients in the metallic ureteral stent group and 15 (41.7%) patients in the control group. A Kaplan–Meier analysis and log‐rank test showed no significant differences between two groups in the overall survival (P = 0.673). One or more complications developed in 19 (32.2%) patients in the metallic ureteral stent group and 18 (38.3%) patients in the control group (P = 0.409). Renal dysfunction after the replacement of the ureteral stent developed in 9 (15.3%) patients in the metallic ureteral stent group and 14 (29.8%) patients in the control group. No patients developed a urinary tract infection (UTI) that required hospitalization in the metallic ureteral stent group, whereas 3 (6.4%) patients in the control group had a UTI that was treated with hospitalization. The average workload score in the six subscales was analyzed, and the scores for mental demand and performance were higher in the metallic ureteral stent group, although there was no significant difference between the metallic and polymeric ureteral stent groups.

Conclusions

Metallic ureteral stents showed favorable ureteral stent patency and reduced the workload for urologists.

Outcome of Palliative Urinary Diversion and Observation for Malignant Extrinsic Ureteral Obstruction

Background: Urologists are often referred to manage the extrinsic malignant ureteral obstruction (MUO) caused by nonurological malignancies. Usually palliative urinary diversion (ureteral stent or nephrostomy) will be performed; however, in the cases of no symptom or poor prognosis, observation (OBS) without any intervention will be selected. There are few reports about outcome of the OBS policy for MUO. Objective: To evaluate the outcome of palliative urinary diversion or OBS for MUO. Design: We retrospectively reviewed the selection of treatment and the prognosis. Setting/Subjects: A total of 151 cases were introduced to our department as MUO between April 2011 and December 2016. Measurements: The patients were divided to immediate palliative urinary diversion (immediate-DIV) or OBS. The latter patients were subdivided to OBS followed by deferred palliative urinary diversion (deferred-DIV), and observation only (OBS-only). Results: There was no significant difference between immediate-DIV and OBS about overall survival (OS) from the consultation. In OBS group, deferred-DIV did not prolong prognosis from the consultation more than OBS-only. In the same way, there was no significant difference between immediate-DIV and deferred-DIV in OS from the intervention. Unfavorable prognostic factors for OS were lack of anticancer treatment after consultation, symptoms of MUO, and gastrointestinal cancer. When we classified the patients by these factors, the group with three factors showed significantly poorer prognosis than the others. Conclusion: Immediate-DIV or OBS did not influence the prognosis in the whole patients. Three prognostic factors that will be judged by urologists easily might be useful for the indication and timing of palliative urinary diversion.

Ureteral stent placement and percutaneous nephrostomy in the management of hydronephrosis secondary to cervical cancer

OBJECTIVE

This study aimed to evaluate the efficacy of ureteral stent placement for the treatment of hydronephrosis secondary to cervical cancer and analyze factors that may predict failure of ureteral stent placement and the differences between ureteral stent placement and percutaneous nephrostomy.

STUDY DESIGN

Clinical data of patients with cervical cancer complicated with hydronephrosis admitted to our hospital from July 2008 to August 2018 were retrospectively analyzed. To evaluate the efficacy of ureteral stent placement and percutaneous nephrostomy in the management of hydronephrosis secondary to cervical cancer.

RESULTS

A total of 89 patients were analyzed. A ureteral stent was successfully placed in 60 patients. Indwelling stent failed in 29 patients, and then percutaneous nephrostomy was performed. Both surgical procedures were safe and effective. There was a significant correlation between the success rate of ureteral stent placement and the degree of hydronephrosis and the length of the ureteral obstruction. There was no significant difference in the incidence of complications following ureteral stent placement and percutaneous nephrostomy, while there were significant differences between the two treatment modalities in terms of surgical time, hospitalization time, and surgical cost.

CONCLUSION

Ureteral stent placement is the preferred method for the treatment of hydronephrosis secondary to cervical cancer. However, in patients with more severe hydronephrosis and ureteral obstruction >3 cm in length, percutaneous nephrostomy may be more appropriate.

Renal function is associated with prognosis in stent-change therapy for malignant ureteral obstruction

Purpose

The authors performed this study to investigate the risk factors for predicting stent failure and to evaluate its impact on prognosis.

Materials and Methods

Between January 2002 and March 2017, we retrospectively reviewed 117 consecutive patients who underwent retrograde ureteral stenting and exchanging at least once every 3 months for malignant ureteral obstruction. The patients were classified according to their pre-stenting chronic kidney disease (CKD) stage. The factors affecting stent failure were analyzed using a logistic regression model. Overall survival (OS) was estimated, and the prognostic significance of each variable was estimated using Cox proportional-hazards regression modeling.

Results

Before stenting, 91 patients were CKD stages 1–3 and 26 patients were CKD stages 4–5. These two groups differed significantly only in pre-stenting estimated glomerular filtration rate (eGFR), bilateral obstruction, and pre-stenting pyuria. Among the 117 patients, stent failure occurred in 30 patients (25.6%), and there were no differences between the groups. Pre-stenting pyuria and post-stenting complications were significant predictors of stent failure. There were 79 deaths in total, including 56 in the CKD stages 1–3 group and 23 in the CKD stages 4–5 group. In the multivariate analysis predicting patient OS, pre-stenting eGFR and post-stenting disease progression were significant factors.

Conclusions

Internal ureteral stenting was effective for maintaining renal function in malignant ureteral obstruction. However, it did not restore renal function, which is related to the prognosis of the patients. Therefore, to improve patients' renal function and prognosis, patients who require stenting must be quickly recognized and treated.

Comparison of single and tandem ureteral stenting for malignant ureteral obstruction: a prospective study of 104 patients

OBJECTIVES

The aim of this study was to compare single and tandem ureteral stenting in the management of malignant ureteral obstruction (MUO).

METHODS

Our hospital's institutional review board approved this prospective study. Between November 2014 and June 2017, single ureteral stenting was performed in 56 patients (94 renal units) and tandem ureteral stenting in 48 patients (63 renal units) for MUO. A comparative analysis of the technical success rate, patient survival, stent patency, and complications was performed.

RESULTS

Similar demographic data were observed in patients receiving either single or tandem ureteral stenting. The technical success rate was 93.6% (88/94) for single ureteral stenting and 95.2% (60/63) for tandem ureteral stenting. There was no difference in overall survival between patients receiving single or tandem ureteral stenting (p = 0.41), but the duration of stent patency in tandem ureteral stenting was significantly longer (p = 0.022). The mean patency time was 176.7 ± 21.3 days for single ureteral stenting, and 214.7 ± 21.0 days for tandem ureteral stenting. The complications of ureteral stenting were urinary tract infection (n = 18), lower urinary tract symptoms (n = 5), haematuria (n = 3), and stent migration (n = 1).

CONCLUSIONS

Tandem ureteral stenting is a safe and feasible treatment for MUO, and had better efficacy compared to single ureteral stenting.

KEY POINTS

• Ureteral stenting is an established treatment for the management of malignant ureteral obstruction (MUO) • Prospective single-centre study showed that tandem ureteral stenting is a safe and feasible treatment for MUO • Tandem ureteral stenting provides longer stent patency compared to single ureteral stenting in patient with MUO.

Gastrointestinal cancer and bilateral hydronephrosis resulted in a high risk of ureteral stent failure

Background

Urologists frequently encounter malignant ureteral obstruction (MUO) caused by advanced urological or non-urological malignant disease, but the treatment policy is unclear. The present study examined the risk factors for predicting ureteral stent failure in patients with MUO after ureteral stent insertion and the change in the renal function after retrograde ureteral stent insertion in cases of bilateral hydronephrosis.

Methods

A total of 39 patients who required ureteral stent placement for MUO at Yokohama City University Medical Center (Yokohama, Japan) between February 2007 and May 2016 were included in this study. The age, gender, type of cancer, hydronephrosis side, pre-stenting estimated glomerular filtration rate (eGFR), and eGFR increase were assessed as predictive factors for stent failure. Among these 39 patients, 25 showed bilateral hydronephrosis. Thirteen of these patients had bilateral ureteral stents placed, and the remaining 12 had a unilateral ureteral stent placed. The renal function and overall survival (OS) were analyzed between these two groups.

Results

Among all 39 patients, 9 (23.1%) had stent failure. A univariate analysis revealed that causative disease (gastrointestinal cancer vs. others; p = 0.045) and laterality of hydronephrosis (bilateral vs. unilateral; p = 0.05) were associated with stent failure. A multivariate analysis revealed that only age (hazard ratio, 0.938; 95% confidence interval, 0.883–0.996; p = 0.038) was associated with stent failure. A Kaplan-Meier analysis and log-rank test indicated that having a unilateral ureteral stent placed was not correlated with a lower OS rate than having bilateral ureteral stents placed (p = 0.563). Among patients with bilateral hydronephrosis, the increase in the eGFR of those who had bilateral ureteral stents placed was not significantly different from that of those who had a unilateral ureteral stent placed (p = 0.152).

Conclusions

We revealed that age > 60 years was helpful for predicting stent failure. MUO due to gastrointestinal cancer and bilateral hydronephrosis may be predictive of stent failure. These factors may help urologists decide the optimal time to perform early percutaneous nephrostomy. These findings suggest that patients with bilateral hydronephrosis do not necessarily need to have a ureteral stent placed into both sides of the hydronephrosis.

Disease- and Treatment-related Complication on F-18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Oncology Practice: A Pictorial Review

F-18-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) is routinely performed in oncology patients for various indications including staging, restaging, recurrence detection, and treatment response evaluation. Many disease- and treatment-related complications can be incidentally detected on PET/CT, which may be due to the complication of radiotherapy, chemotherapy, intervention, or primary tumor itself. Some of these complications could be life threatening and need urgent intervention. Therefore, these incidental findings should be recognized on PET/CT and immediately informed to the treating physicians if required urgent intervention.

Retrograde pyelography predicts retrograde ureteral stenting failure and reduces unnecessary stenting trials in patients with advanced non-urological malignant ureteral obstruction

Objective

To evaluate predictive factors for retrograde ureteral stent failure in patients with non-urological malignant ureteral obstruction.

Materials and methods

Between 2005 and 2014, medical records of 284 malignant ureteral obstruction patients with 712 retrograde ureteral stent trials including 63 (22.2%) having bilateral malignant ureteral obstruction were retrospectively reviewed. Retrograde ureteral stent failure was defined as the inability to place ureteral stents by cystoscopy, recurrent stent obstruction within one month, or non-relief of azotemia within one week from the prior retrograde ureteral stent. The clinicopathological parameters and first retrograde pyelographic findings were analyzed to investigate the predictive factors for retrograde ureteral stent failure and conversion to percutaneous nephrostomy in multivariate analysis with a statistical significance of p < 0.05.

Results

Retrograde ureteral stent failure was detected in 14.1% of patients. The mean number of retrograde ureteral stent placements and indwelling duration of the ureteral stents were 2.5 ± 2.6 times and 8.6 ± 4.0 months, respectively. Multivariate analyses identified several specific RGP findings as significant predictive factors for retrograde ureteral stent failure (p < 0.05). The significant retrograde pyelographic findings included grade 4 hydronephrosis (hazard ratio 4.10, 95% confidence interval 1.39–12.09), irreversible ureteral kinking (hazard ratio 2.72, confidence interval 1.03–7.18), presence of bladder invasion (hazard ratio 4.78, confidence interval 1.81–12.63), and multiple lesions of ureteral stricture (hazard ratio 3.46, confidence interval 1.35–8.83) (p < 0.05).

Conclusion

Retrograde pyelography might prevent unnecessary and ineffective retrograde ureteral stent trials in patients with advanced non-urological malignant ureteral obstruction.

Change of Renal Parenchymal Width in Patients with Unilateral Ureteral Stent: A Bicenter Retrospective Study

PURPOSE

To determine whether kidney sizes were changed after ureteral stents were instilled, and if so, what parameters were significant.

METHODS

Parenchymal width (PW) of 98 patients with unilateral ureteral stents was measured from the coronal view of CT scans for both stented and unstented contralateral kidney. The mean PW and % change of mean PW were calculated before stenting and at the time of last stent change. Estimated glomerular filtrate rate (eGFR) was recorded as well.

RESULTS

The mean duration of ureteral stent indwelled was 15.6 ± 10.2 (mean ± SD) months. The change of mean PW of stented kidneys and unstented contralateral kidneys was -16.9 ± 16.4 (mean ± SD)% and 3.6 ± 10.7%, respectively. eGFR before and at the time of the last stent change did not show significant difference (p = 0.294). Duration of ureteral stent indwelled was found to be inversely related to the % change of mean PW (Spearman's correlation coefficient = -0.291, p < 0.001).

CONCLUSIONS

For unilateral ureteral obstruction, kidney size was decreased over time in spite of indwelling ureteral stent. This finding can be overlooked by clinicians due to compensatory growth of contralateral kidney and resultant normal eGFR.

Outcomes of patients with ureteral obstruction who achieved stent-free state following balloon dilatation

OBJECTIVE

The aim of this study was to assess the therapeutic role of ureteral stent removal following balloon dilatation (BD) in patients with a stent implanted for unilateral ureteral obstruction and with normal contralateral renal function.

MATERIALS AND METHODS

This retrospective cohort study consisted of 37 consecutive patients with unilateral ureteral obstruction whose stents were removed after BD. All patients satisfied the following criteria: normal contralateral renal function, no evidence of malignancy, and the patient was eager to obtain a stent-free state (SFS) without invasive treatment. The relative function of the affected kidney and total renal function before and after stent removal were analyzed using renal scans and estimated glomerular filtration rate (eGFR). A successful outcome was defined as SFS without pain or febrile urinary tract infection plus maintenance of eGFR.

RESULTS

The mean age of all patients was 58.2 years. The mean follow-up periods before and after stent removals were 15.7 and 23.6 months, respectively. The most common underlying cause of ureteral obstruction was pelvic or abdominal surgery (51.4%). Of the 37 patients, 32 (86.5%) achieved successful SFS at last follow-up. Overall in the 37 patients, the eGFR (from 77.1 to 69.8 ml/min/1.73 m(2); p = 0.017) and relative renal function of the affected kidney (from 35.5 to 30.2%; p = 0.002) were significantly compromised. However, the reduction in total eGFR was not significant (p = 0.075) in the successful SFS group.

CONCLUSION

The removal of a stent with BD is a viable option for achieving a successful SFS in patients with unilateral ureteral obstruction.

Predicting the failure of retrograde ureteral stent insertion for managing malignant ureteral obstruction in outpatients

Malignant ureteral obstruction (MUO) is an unpropitious sign that is commonly observed in patients with advanced incurable cancer. The present study aimed to evaluate predictive factors for the failure of retrograde ureteral stent insertion in the management of MUO in outpatients. A total of 164 patients with MUO were retrospectively assessed in this study. Clinical factors, including age, gender, type of malignancy, level of obstruction, cause of obstruction, pre-operative creatinine level, degree of hydronephrosis, condition of the contralateral ureter, prior radiotherapy, Eastern Cooperative Oncology Group performance status (ECOG PS), bladder wall invasion and technical failure, were recorded for each case. Univariate and multivariate logistic regression analyses were used to investigate the risk factors for predicting the failure of retrograde ureteral stent insertion. In total, 38 out of 164 patients experienced bilateral obstruction, therefore, a total of 202 ureteral units were available for data analysis. The rate of insertion failure in MUO was 34.65%. Multivariate analyses identified ECOG PS, degree of hydronephrosis and bladder wall invasion as independent predictors for insertion failure. Overall, the present study found that rate of retrograde ureteral stent insertion failure is high in outpatients with MUO, and that ECOG PS, degree of hydronephrosis and bladder invasion are potential independent predictors of insertion failure.

Early Application of Permanent Metallic Mesh Stent in Substitution for Temporary Polymeric Ureteral Stent Reduces Unnecessary Ureteral Procedures in Patients With Malignant Ureteral Obstruction

OBJECTIVE

To identify risk factors for metal stent failure in patients who received polymeric double J (PDJ) ureteral stents for malignant ureteral obstructions (MUOs) and review our clinical experiences using a ureteral metallic stent.

PATIENTS AND METHODS

Patients who underwent metallic stent placement to replace a double J ureteral stent for nonurological MUO between January 2011 and February 2014 were included. The collected data included gender, age, laterality, cause of obstruction, PDJ ureteral stenting duration, immediate success of the metal stent, and additional procedures to relieve obstruction after metal stenting (eg, additional metal stenting or percutaneous nephrostomy (PCN) indwelling catheter placement). Cox regression tests were used for the statistical analyses.

RESULTS

In this analysis 40 ureteral units were included. There was no initial technical failure. However, 9 (22.5%) units required additional procedures due to de novo ureteral obstruction, including additional indwelling metal stents (7.5%), additional PDJ stenting (10%), or indwelling percutaneous nephrostomy (5%). Univariate and multivariate analyses revealed that the duration of previous PDJ ureteral stenting was an independent prognostic factor for predicting ureteral metal stent failure (hazard ratio = 1.063, 95% confidence interval = 1.004-1.125; P = .037).

CONCLUSION

Long-term indwelling of a PDJ ureteral stent increases the risk of additional management for de novo ureteral stricture after ureteral metal stent replacement for nonurological MUO. Our data suggest that careful patient selection and counseling for those at high risk are needed when metal stent replacement is considered for patients with long-term PDJ ureteral stents for MUO.

A prognostic model for survival after palliative urinary diversion for malignant ureteric obstruction: a prospective study of 208 patients

OBJECTIVE

To identify factors associated with survival after palliative urinary diversion (UD) for patients with malignant ureteric obstruction (MUO) and create a risk-stratification model for treatment decisions.

PATIENTS AND METHODS

We prospectively collected clinical and laboratory data for patients who underwent palliative UD by ureteric stenting or percutaneous nephrostomy (PCN) between 1 January 2009 and 1 November 2011 in two tertiary care university hospitals, with a minimum 6-month follow-up. Inclusion criteria were age >18 years and MUO confirmed by computed tomography, ultrasonography or magnetic resonance imaging. Factors related to poor prognosis were identified by Cox univariable and multivariable regression analyses, and a risk stratification model was created by Kaplan-Meier survival estimates at 1, 6 and 12 months, and log-rank tests.

RESULTS

The median (range) survival was 144 (0-1084) days for the 208 patients included after UD (58 ureteric stenting, 150 PCN); 164 patients died, 44 (21.2%) during hospitalisation. Overall survival did not differ by UD type (P = 0.216). The number of events related to malignancy (≥4) and Eastern Cooperative Oncology Group (ECOG) index (≥2) were associated with short survival on multivariable analysis. These two risk factors were used to divide patients into three groups by survival type: favourable (no factors), intermediate (one factor) and unfavourable (two factors). The median survival at 1, 6, and 12 months was 94.4%, 57.3% and 44.9% in the favourable group; 78.0%, 36.3%, and 15.5% in the intermediate group; and 46.4%, 14.3%, and 7.1% in the unfavourable group (P < 0.001).

CONCLUSIONS

Our stratification model may be useful to determine whether UD is indicated for patients with MUO.

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.

The use of internal stents in chronic ureteral obstruction

PURPOSE

Despite the lack of a well delineated definition, chronic ureteral obstruction imposes significant quality of life loss, increased pathological morbidity and risk of mortality as well as substantial economic burden. Ureteral stenting serves as an important therapeutic option to alleviate obstruction. Thus, we assessed the recently published literature on chronic ureteral obstruction; treatment options; types, benefits and shortcomings of current ureteral stents; as well as outcomes and complications of chronic ureteral stenting, with the goal of providing concise management guidelines.

MATERIALS AND METHODS

A systemic literature review was performed on Embase™, PubMed®, Cochrane Controlled Trials Register and Google Scholar™ on ureteral obstruction and internal ureteral stents. Relevant reviews, original research articles and their cited references were examined, and a synopsis of original data was generated on a clinically oriented basis.

RESULTS

Chronic ureteral obstruction can be classified into compression that is either intrinsic or extrinsic to the ureteral wall, or obstruction that is of a benign or malignant origin. Patients with malignant ureteral obstruction generally have a poor prognosis and are often difficult to treat. The aim of stenting is to adequately drain the upper urinary tracts while minimizing hospitalization and the negative impact on quality of life. Facing the challenge of chronic ureteral obstruction, novel stents with new compositions, materials, coatings and designs have been developed. Metallic stents are emerging as efficacious and financially viable alternatives. Early stent related complications include iatrogenic injury, stent migration or patient discomfort, while late complications include infection, difficulties with stent exchange, hardware malfunction, infection and stent encrustation.

CONCLUSIONS

Stenting in chronic ureteral obstruction is a complex and challenging problem. Much work is being done in this area and many options are being explored.

Subcutaneous nephrovesical bypass: Treatment for ureteral obstruction in advanced metastatic disease

The aim of the present study was to explore the value of subcutaneous nephrovesical bypass (SNVB) for the treatment of ureteral obstruction due to pelvic metastatic disease. SNVB stents (n=30) were implanted in 24 patients with advanced metastatic disease between January 2008 and December 2012. Urinalysis, serum creatinine (SCr), glomerular filtration rate (GFR), quality of life (QoL) scores, and renal ultrasonography were evaluated at follow-up. The SNVB procedures were successful in all 24 patients. Patient follow-ups occurred at an average of 10.6 months. Preoperative hydronephrosis was eliminated in 16 cases (53.3%) and reduced in the remaining patients. Following surgery, SCr levels reduced significantly from 256±46 to 124±23 μmol/l (P<0.001). GFRs increased from 25±4.8 to 45±5.3 ml/min (P<0.01). The mean QoL scores were 3.4±1.4 preoperatively and 7.6±1.0 postoperatively (P<0.001). The results showed that SNVB is a minimally invasive, effective and safe procedure for patients with ureteral obstruction resulting from advanced malignant disease. As an alternative procedure to percutaneous nephrostomy, SNVB offers patients a better QoL.

Outcomes of stent-change therapy for bilateral malignancy-related ureteral obstruction

OBJECTIVE

To study the long-term outcomes of stent-change therapy for malignancy-related ureteral obstruction in terms of renal function outcomes.

METHODS

We retrospectively reviewed 87 consecutive patients who underwent bilateral ureteral stenting for malignant bilateral ureteral obstruction. Predictive value of clinical variables, such as age, sex, comorbidities, renal function at time of stenting, and securing of the dominant functional kidney or both with early percutaneous nephrostomy (PCN) conversion on renal function preservation, were analyzed.

RESULTS

The mean serum Cr level was 3.3 mg/dl at the time of bilateral stenting, which significantly decreased to 1.6 mg/dl at 6 months post-stenting and progressively deteriorated to 2.3 mg/dl at 3 years post-stenting. Chronic kidney disease (CKD) stage 4 or 5 developed in 18.3% of patients at 6 months post-stenting and in 57.2% at 3 years post-stenting. During the follow-up period, 12 patients (13.8%) had PCN conversion. Patients who had early PCN conversion before progression to CKD 4 or more tended to show a better renal function outcome than patients with CKD 4 or more who had late PCN conversion or no conversion. Multivariate analysis showed that an age older than 55 years, diabetes, and an eGFR<60 before obstructive symptoms or signs were significant predictive factors for the development of CKD stage 4 or more.

CONCLUSIONS

To preserve renal function, patients with bilateral malignant ureteral obstruction, especially those aged 55 or more or with diabetes or poor baseline renal function, should be considered for early PCN conversion in the dominant functional kidney or both.

Evaluation of 18F-FDG excretion patterns in malignant obstructive uropathy

OBJECTIVES

This study aims to evaluate whether (18)F-FDG excretion patterns reflect renal function in malignant obstructive uropathy and to evaluate if these patterns predict internal ureteral stent success.

METHODS

One hundred twelve patients who underwent PET/CT for abdominal tumors and displayed hydronephrosis on CT and 59 patients who underwent PET/CT for cancer screening were included in a retrospective study. Hydronephrosis was graded by initial CT and correlated with visual analysis of (18)F-FDG renal parenchymal uptake and excretion patterns. Stent insertion was performed for 84 patients after PET. Follow-up CT was reviewed for hydronephrosis improvement.

RESULTS

There were 4 PET patterns in obstructive hydronephrosis which correlated linearly with hydronephrosis severity and serum creatinine levels. Patients with no parenchymal retention and renal excretion (PET pattern 1) showed 97% (28/29) hydronephrosis improvement after stent insertion, and patients with no parenchymal retention and no renal excretion showed 0% (0/9) hydronephrosis improvement after stent insertion. Multivariate analysis showed creatinine levels and PET pattern predicted stent success, but CT hydronephrosis did not.

CONCLUSIONS

There are 4 PET patterns of obstructive hydronephrosis which correlated with hydronephrosis grade and creatinine levels. Some of these PET patterns can be useful in the prediction of hydronephrosis improvement after stent insertion. Recognition of these patterns in obstructive hydronephrosis may be helpful in improving patient prognosis and quality of life.

Current status of minimally invasive endoscopic management of ureteric strictures

Endourological techniques are used more often nowadays in the treatment of ureteric strictures of various etiologies. Advances in technology have provided new tools to the armamentarium of the endoscopic urological surgeon. Numerous studies exist that investigate the efficiency and safety of each of the therapeutic modalities available. In this review, we attempt to demonstrate the available and contemporary evidence supporting each minimally invasive modality in the management of ureteric strictures.

Prognostic marker for patients with malignant ureter obstruction

PURPOSE

To investigate the relationship between overall survival (OS) and prognostic risk factors for patients with malignant ureteral obstruction.

PATIENTS AND METHODS

We retrospectively evaluated 214 patients who had received a nephrostomy for ureteral obstruction because of malignancy. Univariate and multivariate Cox regression models addressed OS.

RESULTS

The median OS was 6.4 months. The OS at 1, 3, 6, and 12 months were 89.5%, 72.4%, 53.0%, and 26.5%, respectively. Using univariate Cox regression analysis, serum levels of creatinine (P = .0131), albumin (P < .0001), sodium (P < .0001), potassium (P = .0141), corrected calcium (P = .0167), C-reactive protein (P < .0001), white blood cell count (P = .0246), and the number of events related to malignant dissemination (P < .0001) were associated with OS. Using multivariate Cox regression analysis, serum levels of albumin (P = .0147), sodium (P = .0046), C-reactive protein (P < .0001), and the number of events related to malignant dissemination (P = .0002) were independent predictors of OS.

CONCLUSION

Low serum levels of albumin and sodium and the number of events related to malignant dissemination before PCN were independent factors associated with a poor prognosis. High serum C-reactive protein level was also associated with a poor prognosis using multivariate analysis.

Predicting factors for stent failure-free survival in patients with a malignant ureteral obstruction managed with ureteral stents

Purpose

To determine predictive factors for stent failure-free survival in patients treated with a retrograde ureteral stent for a malignant ureteral obstruction.

Materials and Methods

We retrospectively reviewed 71 patients who underwent insertion of a cystoscopic ureteral stent due to a malignant ureteral obstruction between May 2004 and June 2011. Performance status, type of cancer, hydronephrosis grade, location of the obstruction, presence of bladder invasion, C-reactive protein (CRP), serum albumin, and inflammation-based prognostic score (Glasgow prognostic score, GPS) were assessed using a Cox proportional regression hazard model as predicting factors for stent failure.

Results

A univariate analysis indicted that hypoalbuminemia (<3.5 g/dL; hazard ratio [HR], 2.43; 95% confidence interval [CI], 1.21 to 4.86; p=0.012), elevated CRP (≥1 mg/dL; HR, 4.79; 95% CI, 2.0 to 11.1; p=0.001), and presence of a distal ureter obstruction (HR, 3.27; 95% CI, 1.19 to 8.95; p=0.021) were associated with stent failure-free survival. A multivariate analysis revealed that the presence of a mid and lower ureteral obstruction (HR, 3.27; 95% CI, 1.19 to 8.95; p=0.007), GPS ≥1 (HR, 7.22; 95% CI, 2.89 to 18.0; p=0.001), and elevated serum creatinine before ureteral stent placement (>1.2 mg/dL; HR, 2.16; 95% CI, 1.02 to 4.57; p=0.044) were associated with stent failure-free survival.

Conclusions

A mid or lower ureteral obstruction, GPS ≥1, and serum creatinine before ureteral stent insertion >1.2 mg/dL were unfavorable predictors of stent failure-free survival. These factors may help urologists predict survival time.

Percutaneous nephrostomy versus indwelling ureteral stent in the management of gynecological malignancies

OBJECTIVES

The aims of this study were to evaluate the efficacy of retrograde ureteral stenting and to identify the predictive factors for potential failure of this technique in women with advanced gynecologic malignancies.

METHODS

From 2006 to 2010, a retrospective analysis was performed on a total of 75 patients with ureteral obstruction due to gynecologic malignancies. This population was divided into group 1 (n = 50) in which retrograde stent placement was successful, and group 2 (n = 25) in which stent placement failed and subsequent percutaneous nephrostomy tube placement was required. Multivariate analysis was done to identify predictors of the failure of ureteral stent insertion.

RESULTS

Multivariate analysis revealed that mean preprocedureal serum cystanin C greater than 2.5 mg/L and length of the ureteral obstruction greater than 3 cm were significant predictors of stent failure. Neither the causes nor location of obstruction predicted the need for percutaneous nephrostomy (PCN). No statistical significance was detected among the subgroups of patients with different degrees of hydronephrosis. Statistical significant differences were found between the 2 groups in procedural time, average cost, and mean interval of stent/catheter replacement. However, no statistically significant difference was found in the median survival time and overall stent-related or catheter-related complications between the 2 groups.

CONCLUSIONS

Retrograde ureteral stenting is a first-line option for managing ureteral obstruction caused by gynecologic malignancies. However, in cases where the preprocedureal mean serum cystanin C is greater than 2.5 mg/L and the length of the ureteral obstruction segment is greater than 3 cm, these patients may be better served by percutaneous drainage.

Current outcome of patients with ureteral stents for the management of malignant ureteral obstruction

PURPOSE

We analyzed the prognostic factors associated with overall survival and predictive factors of stent failure in patients treated with an indwelling retrograde ureteral stent for malignant ureteral obstruction.

MATERIALS AND METHODS

Among 186 Japanese patients treated with an indwelling retrograde ureteral stent for ureteral obstruction from January 2005 to March 2010, 61 with malignant ureteral obstruction and 95 ureteral units were analyzed retrospectively.

RESULTS

Median survival was estimated at 228 days. Unfavorable prognostic factors of overall survival were no treatment after indwelling retrograde ureteral stent placement (p = 0.023) and a serum creatinine before indwelling retrograde ureteral stent placement of 1.2 mg/dl or greater (p = 0.016). Overall survival differed significantly among cancer groups (p <0.001) as did stent failure-free survival (p = 0.011). Overall survival differed significantly among 3 risk groups divided according to the score calculated with regard to prognostic factors (p <0.001).

CONCLUSIONS

Gynecologic cancer was a significant favorable predictor of stent failure-free survival. Patients treated with an indwelling retrograde ureteral stent for malignant ureteral obstruction were divided into 3 groups, which showed significant differences in overall survival. This risk classification may help urologists predict survival time.

Diagnosis and management of infectious complications in critically ill patients with cancer

Cancer and its treatments lead to profound suppression of innate and acquired immune function. In this population, bacterial infections are common and may rapidly lead to overwhelming sepsis and death. Furthermore, infections caused by viral and fungal pathogens should be considered in patients who have specific immune defects. As cancer therapies have become more aggressive the risk for infection has increased and many patients require intensive care support. Despite improvements in long-term survival, infections remain a common complication of cancer therapy and accounts for the majority of chemotherapy-associated deaths. By understanding the host defense impairments and likely pathogens clinicians will be better able to guide diagnosis and management of this unique population.

Endourologic management of malignant ureteral obstruction: indications, results, and quality-of-life issues

Obstruction of the upper urinary tract is a problem commonly faced by practicing urologists. The constant evolution in endourology has effectively facilitated minimally invasive management of upper-tract obstruction. In a case in which malignancy is the cause of obstruction, however, the situation significantly changes. Questions arise regarding the need for relieving the obstruction, the means to accomplish this, and the benefits and drawbacks of each technique regarding both their efficacy and their impact on the patients well-being and the crucial issue of quality of life in the face of malignancy.

Serum creatinine predicts success in retrograde ureteral stent placement in patients with pelvic malignancies

OBJECTIVES

To evaluate serum hemoglobin, baseline serum creatinine, serum creatinine at the diagnosis of obstructive hydronephrosis, and the increase in serum creatinine greater than baseline to predict for success in retrograde ureteral stent placement in patients with pelvic malignancies.

METHODS

In a retrospective chart review, we identified 57 patients at our institution with obstructive hydronephrosis secondary to pelvic malignancies in which retrograde ureteral stent placement was attempted from January 2002 to May 2005. The patient charts were reviewed for the baseline serum creatinine, preoperative serum creatinine and hemoglobin, and serum creatinine at presentation of obstructive hydronephrosis. This population was divided into group 1 (n = 31, 54%), in which retrograde stent placement was successful, and group 2 (n = 26, 46%), in which stent placement failed and subsequent percutaneous nephrostomy tube placement was required. The Student t test was used to determine whether a significant difference existed between the two groups for each laboratory parameter.

RESULTS

The serum hemoglobin and baseline creatinine were not significantly different between the two groups and could not be used to predict for the success or failure of stent placement (P = 0.10 and P = 0.59, respectively). However, the average serum creatinine at presentation of obstructive hydronephrosis was significantly different between group 1 (2.4 +/- 1.4 ng/dL) and group 2 (5.3 +/- 6.3; P = 0.014), as was an increase in serum creatinine greater than baseline (P = 0.002).

CONCLUSIONS

The results of this study have shown that the serum creatinine level at the presentation of obstructive hydronephrosis can be used to predict for success in retrograde ureteral stent placement in patients with pelvic malignancies.

Antibiotic pretreatment of hydrogel ureteral stent

PURPOSE

To compare bacterial adhesion to hydrogel-coated and uncoated ureteral stents. The antimicrobial activity of coated and uncoated stents treated with commonly used antibiotic solutions also was evaluated.

MATERIALS AND METHODS

Hydrogel coated and uncoated stent segments were dipped in different antibiotic solutions (ciprofloxacin, gentamicin, and cefazolin). Normal saline was used as the control. The segments were incubated in separate broths of Escherichia coli and Enterococcus faecalis to reach the log phase. They were sonicated to free the bacteria, and colony-forming units were determined after 48 hours. To evaluate antibacterial activity, hydrogel-coated and uncoated stent segments were dipped in the above-mentioned antibiotic solutions. Normal saline was used as the control. Segments were incubated in separate Mueller-Hinton agar plates inoculated with E. coli or Enterococcus faecalis, and the zones of inhibition were determined at 24 hours. The duration of antibacterial activity for each bacterium-antibiotic combination also was studied.

RESULTS

Hydrogel coating did not significantly reduce bacterial adhesion. Zones of inhibition around stent pieces dipped in antibiotic solutions differed with the organism and the antibiotic. Cefazolin produced a significantly larger zone of inhibition with hydrogel-coated stent, but the duration of antibacterial activity was similar to that of uncoated stent. Hydrophilic coating significantly increased the duration of antibacterial activity of ciprofloxacin and gentamicin.

CONCLUSION

Hydrogel coating on the surface of ureteral stents does not prevent or reduce bacterial adhesion. However, after antibiotic treatment, stents exhibit antibacterial activity in the local environment at greater intensity and for a longer time, depending on the bacterium-antibiotic combination.

Retrograde ureteral stents for extrinsic ureteral obstruction: nine years' experience at University of Michigan

OBJECTIVES

To review our experience with retrograde ureteral stenting for extrinsic ureteral obstruction because previous reports have suggested only moderate success.

METHODS

We performed a retrospective review of the course of patients who underwent retrograde ureteral stent placement from March 1996 to April 2005. The gathered clinical parameters included stent failure, which was defined as any ureteral unit (UU) that remained obstructed.

RESULTS

A total of 54 patients treated for extrinsic ureteral compression, representing 87 UUs, were followed for an average of 16 months (range 0.7 to 98) in successful cases. Of the stents, 68% were placed for malignancy, 23% for retroperitoneal fibrosis, and 9% for benign masses. The overall success rate was 84%, with malignancy, retroperitoneal fibrosis, and benign masses having an 81%, an 85%, and a 100% success rate, respectively. Fourteen UUs failed, with a mean time to stent failure of 4.8 months (range 0.07 to 27). Multiple stents were placed in 54 UUs, with a mean of 5.5 stent exchanges, at a mean interval of 3.6 months. On univariate analysis, only greater posttreatment creatinine was associated with stent failure (P <0.01), although stents placed for localized disease tended to be more successful than those placed for regional disease (100% versus 81%, P = 0.07).

CONCLUSIONS

If initial stent placement was possible, extrinsic ureteral obstruction was managed successfully with retrograde ureteral stent placement in 84% of cases. Because no preoperative characteristics could be identified, except for a trend toward less success in cases of regional disease, retrograde stenting can be considered first-line treatment in patients with extrinsic ureteral obstruction.

The outcome with ureteric stents for managing non-urological malignant ureteric obstruction

OBJECTIVE

To investigate the clinical outcome using ureteric stents to manage ureteric obstruction in advanced non-urological malignancies.

PATIENTS AND METHODS

We retrospectively reviewed the use of ureteric stents (Endo-sof, Cook Urological, Spencer, IN, USA) placed for malignant ureteric obstruction from June 2001 to September 2006. The clinical and radiological variables for predicting the failure of stent insertion, functional stent failure and death were analysed.

RESULTS

In all, 86 patients with a non-urological malignant ureteric obstruction were treated by ureteric stenting; 13 (15%) had failure of retrograde stent insertion, and of the remaining 73, 12 (16%) had stent failures during the subsequent follow-up. The risk of failure for stent insertion significantly increased with male gender (hazard ratio 6.45, P = 0.028) and the presence of bladder invasion (hazard ratio 27.04, P < 0.001). There was no independent predictor of stent failure in univariate analysis. Of the 86 patients, 54 (63%) died with a mean survival time of 8.6 months after an initial attempt to place a stent, and 41 (48%) died within 1 year. Multivariate analysis showed that low performance status, upper ureteric obstruction and no chemotherapy after stenting were independently associated with a poor prognosis (P = 0.03, 0.004 and 0.003, respectively).

CONCLUSION

The method of diversion for a malignant ureteric obstruction should be carefully discussed with male patients or if there is bladder invasion. Patients with a low performance status, upper ureteric obstruction and no scheduled chemotherapy after stenting had a poor survival time.