Predicting the success of retrograde stenting for managing ureteral obstruction

PURPOSE: Retrograde ureteral stenting is often considered the first line option for relieving ureteral obstruction when temporary drainage is indicated. Several retrospective studies have implied that in cases of extrinsic obstruction retrograde ureteral stenting may fail and, therefore, percutaneous nephrostomy drainage is required. We examined the efficacy of retrograde ureteral stenting for resolving ureteral obstruction and identified clinical and radiological parameters predicting failure. MATERIALS AND METHODS: Enrolled in our prospective study were 92 consecutive patients with ureteral obstruction, which was bilateral in 8. Retrograde ureteral stenting was attempted in all cases by the urologist on call. When stent insertion failed, drainage was achieved by percutaneous nephrostomy. Patients were followed at 3-week intervals for 3 months. Each followup visit included a medical interview, blood evaluation, urine culture and ultrasound. Stent malfunction was defined as continuous flank pain manifesting as recurrent episodes of acute renal colic, 1 or more episodes of pyelonephritis, persistent hydronephrosis or elevated creatinine. Preoperative data and outcomes were compared in cases of intrinsic and extrinsic obstruction. Univariate and multivariate analysis was done to identify predictors of the failure of ureteral stent insertion and long-term function. RESULTS: The etiology of obstruction was intrinsic in 61% of patients and extrinsic in 39%. Extrinsic obstruction, which was associated with a greater degree of hydronephrosis, was located more distal. Retrograde ureteral stenting was successful in 94% and 73% of patients with intrinsic and extrinsic obstruction, respectively. At the 3-month followup stent function was maintained in all patients with intrinsic obstruction but in only 56.4% with extrinsic obstruction. On multivariate logistic regression the type of obstruction, level of obstruction and degree of hydronephrosis were the only predictors of stent function at 3 months. Stent diameter and preoperative creatinine had no predictive value. CONCLUSIONS: Retrograde ureteral stenting is a good solution for most acutely obstructed ureters. In patients with extrinsic ureteral obstruction a more distal level of obstruction and higher degree of hydronephrosis are associated with a greater likelihood of stent failure. These patients may be better served by percutaneous drainage.     

15-year experience with the management of extrinsic ureteral obstruction with indwelling ureteral stents

PURPOSE: We assessed the success of retrograde placement of indwelling ureteral stents in the management of ureteral obstruction due to extrinsic compression. MATERIALS AND METHODS: Between July 1987 and December 2002 adequate followup was available for 101 patients who underwent primary retrograde ureteral stenting for extrinsic ureteral obstruction. Mean age at presentation was 61.4 years (range 33 to 90). Chart review was performed on all patients for primary diagnosis, symptomatology, degree of hydronephrosis, creatinine levels (baseline, treatment and posttreatment), location of compression, size and number of stents used, progression to percutaneous nephrostomy tube (PNT), stent failure, days to stent failure, post-stent therapy and status at last followup. RESULTS: Mean length of followup was 11 months (range 1 to 127). In 101 patients 138 ureteral units (UU) were stented. Total stent failure occurred in 41 (40.6%) patients and 58 (42.0%) UU. A total of 40 (29.0%) UU required PNTs at a mean of 40.3 days (range 0 to 330) with 18 PNTs placed in less than 1 week. Cases of stent failure that did not undergo PNT placement included 18 (13.0%) UU at a mean of 52.4 days (range 3 to 128). A total of 90 (89.1%) patients had metastatic cancer at stenting with 32.2% dead at 5.8 months (range 1 to 32). Univariate and multivariate analyses identified cancer diagnosis, baseline creatinine greater than 1.3 mg/dl and post-stent systemic treatment as predictors of stent failure. Proximal location of compression and treatment creatinine greater than 3.11 mg/dl were marginal predictors of failure on univariate analysis, while proximal location of obstruction was also marginally significant on multivariate analysis. No predictors were identified for early stent failure (less than 1 week). CONCLUSIONS: At almost 1 year followup stent failure due to extrinsic compression occurred in nearly half of treated patients. Analysis of data revealed a diagnosis of cancer, baseline mild renal insufficiency and metastatic disease requiring chemotherapy or radiation as predictors of stent failure. Managing extrinsic compression by retrograde stenting continues to be a practical but guarded decision and should be tailored to each patient.     

Late ureteral obstruction after kidney transplantation

Abstract Today, the incidence of urological complications following renal transplantation is 2 %-10 %. Most of these complications occur within the 1st year and affect the distal ureter. We report on two patients who developed very late ureteral obstruction, 14 and 18 years after transplantation. Both patients had rejection episodes 1 and 10 months prior to the ureteral stenosis. Histological examination of one resected ureter revealed findings strongly suggestive of a rejection process. Open surgery with antirefluxive reimplantation into the bladder was successful in both patients, with a postoperative observation time of 20 and 8 months, respectively. We conclude that a percutaneous nephrostomy may be required in patients with rising creatinine and incipient hydronephrosis even long after transplantation has been performed.     

镍钛形状记忆合金支架治疗良恶性直肠梗阻

目的 探讨镍钛形状记忆合金支架治疗良恶性直肠梗阻的疗效及意义。方法 对 12例恶性肿瘤致直肠狭窄和 1例良性狭窄导致的急慢性直肠梗阻患者实施了支架置入术。支架在冰水中柔软,易压缩,通过手工或乙状结肠镜送至狭窄部位,灌注热水后支架复形扩张。结果 11例患者成功置入, 5 h内恢复了排便。 8例作为永久性姑息治疗, 2例经过充分的肠道准备,择期施行了切除手术, 1例良性狭窄长期带支架维持排便。 2例支架脱落后再次置入。 1例穿孔改行结肠造口。 11例中死亡 6例,生存期 56～ 720 d。其他 5例已存活至今,达 6～ 32个月,无再发肠梗阻。结论 网管状支架能有效地对晚期直肠癌以及具有高危手术因素的患者进行永久性姑息治疗,同时能缓解急性梗阻,避免结肠造口,为择期手术创造条件。配合化疗和免疫治疗,有利于延长患者生存期。     

Late ureteral obstruction after kidney transplantation

Today, the incidence of urological complications following renal transplantation is 2%–10%. Most of these complications occur within the 1st year and affect the distal ureter. We report on two patients who developed very late ureteral obstruction, 14 and 18 years after transplantation. Both patients had rejection episodes 1 and 10 months prior to the ureteral stenosis. Histological examination of one resected ureter revealed findings strongly suggestive of a rejection process. Open surgery with antirefluxive reimplantation into the bladder was successful in both patients, with a postoperative observation time of 20 and 8 months, respectively. We conclude that a percutaneous nephrostomy may be required in patients with rising creatinine and incipient hydronephrosis even long after transplantation has been performed.     

The efficacy and safety of ureteral dilation and long-term type ureteral stent for patients with ureteral obstruction

ObjectiveThis study was conducted to investigate the efficacy and safety of ureteral dilation and placement of a long-term ureteral stent for patients with various types of ureteral obstructions.MethodsWe retrospectively reviewed the records of 39 patients presenting with ureteral obstruction secondary to malignant strictures (n = 9) or nonmalignant strictures (n = 30). The mean age of these patients was 55.8 ± 16.1 years (range, 13–87 years). All patients underwent retrograde ureteral balloon dilation and placement of one to three ureteral stents. Stent patency rate and complications including febrile urinary tract infection, stent encrustation, and stent fragmentation were recorded.ResultsA total of 117 ureteral stents were implanted during the 83 procedures. Three stents were placed in seven patients and two stents in 20 patients. The patency rate was 95.2% with a mean 75-day follow-up. There was no encrustation in 104 stents and Grade 1 in 13 stents. The patency rate was similar between the patients with malignant strictures and those with nonmalignant strictures (100% vs. 94.7%, p = 0.57). However, three episodes of febrile urinary tract infection were noted only in patients with malignant strictures. The improvement of hydronephrosis and complications were also comparable between those patients with ureteral stents indwelling for >90 days and those for <90 days. No stent fragmentation was found in any of the patients.ConclusionWe demonstrated that ureteral dilation and placement of a single or multiple ureteral stents was effective and safe for patients with ureteral obstruction.     

Management and treatment options when facing malignant ureteral obstruction

Malignant ureteral obstruction is an unfortunate finding that can be caused by a wide-ranging number of malignancies with a prognosis of limited survival. Given its presentation and progression, it can be refractory to treatment by traditional single polymeric ureteral stents. With a higher failure rate than causes of benign ureteral obstruction, a number of other options are available for initial management, as well as in cases of first-line therapy failure, including tandem stents, metallic stents, percutaneous nephrostomies and extra-anatomic stents. We reviewed the literature and carried out a PubMed search including the following keywords and phrases: “malignant ureteral obstruction,” “tandem ureteral stents,” “metallic ureteral stents,” “resonance stent,” “metal mesh ureteral stents” and “extra-anatomic stents.” The vast majority of studies were small and retrospective, with a large number of studies related to metallic stents. Given the heterogenous patient population and diversity of practice, it is difficult to truly assess the efficacy of each method. As there are no guidelines or major head-to-head prospective trials involving these techniques, it makes practicing up to the specific provider. However, this article attempts to provide a framework with which the urologist who is presented with malignant ureteral obstruction can plan in order to provide the individualized care on a case-by-case basis. What is clear is that prospective, randomized clinical trials are necessary to help bring evidence-based medicine and guidelines for patients with malignant ureteral obstruction.     

Endothelin in unilateral ureteral obstruction: vascular and cellular effects

PURPOSE: Unilateral ureteral obstruction results in decreased blood flow and tissue loss in the obstructed kidney. This condition is compensated by increased perfusion and trophic changes in the contralateral kidney. Vascular mediators' effects are central to these changes and of these mediators endothelin is the most potent vasoconstrictor known. We explored the role of endothelin and the effects of endothelin receptor blockade in unilateral ureteral obstruction. MATERIALS AND METHODS: Rats were subjected to unilateral ureteral obstruction for 24 hours. Endothelin-1 mRNA expression was determined in kidney extracts from control, obstructed and contralateral (nonobstructed) kidneys. Cortical and medullary blood flow was determined in control and obstructed kidneys, and after endothelin receptor blockade with bosentan. Apoptotic rates were determined in control and obstructed kidneys after treatment with bosentan using the terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end technique.RESULTS After 24 hours of unilateral ureteral obstruction endothelin-1 mRNA expression was increased in the obstructed kidney and decreased in the contralateral kidney. Obstruction was associated with a decrease in renal blood flow, which was reversed by endothelin receptor blockade. Unilateral ureteral obstruction also increased apoptosis, which was blocked by endothelin inhibition. CONCLUSIONS: Endothelin expression increases in the obstructed kidney. Inhibition of its action protects against vascular and cellular changes. Decreased endothelin expression in the contralateral kidney may facilitate trophic changes and compensatory increased blood flow.     

The management of malignant ureteral obstruction treated with ureteral stents

PURPOSE: We developed an algorithm for the management of ureteral obstruction due to malignant extrinsic compression. MATERIALS AND METHODS: We retrospectively reviewed all ureteral stents placed for noncalculous reasons at our institution from January 1, 1990 to January 1, 2004. Further clinical information was gathered from 157 patients with malignant extrinsic ureteral compression. Failure was defined as recurrent ureteral obstruction or an inability to place stents cystoscopically. RESULTS: A total of 157 patients underwent retrograde ureteral stent attempt for malignant extrinsic ureteral obstruction. Mean patient age was 54.7 years (range 23 to 83) and average followup was 13.6 months. Of our patients 61% were women, and the most common cancer diagnoses were ovarian cancer (in 26), lymphoma (17) and cervical cancer (16). A total of 24 patients required immediate percutaneous nephrostomy (PCN) referral. There were 32 patients who experienced a late failure and required PCN (average 180 days after initial stent), and 83 patients in our series (52.9%) who experienced 110 major complications. Type of cancer did not predict need for PCN. However, when invasion into the bladder was noted on cystoscopy, 55.9% (19 of 34, p = 0.008) progressed to PCN referral. A total of 77 patients underwent stent replacement on average 2.8 times and with an interval of 95 days. CONCLUSIONS: In our series patients with malignant extrinsic ureteral compression presenting for ureteral stent(s) experienced a failure rate of 35.7% (56 of 157). Invasion at cystoscopy had a significant predictive value for progression to PCN. We present an algorithm on the management of extrinsic malignant ureteral obstruction.     

Ureteropelvic junction obstruction: an innovative approach combining metallic stenting and virtual endoscopy

PURPOSE: We report our experience with auto-expandable metallic stents for treating ureteropelvic junction obstruction. MATERIALS AND METHODS: We treated 4 patients with a mean age of 45 years who had ureteropelvic junction obstruction with placement of a self-expandable intraureteral metallic stent (Wallstent, Schneider, Zurich, Switzerland). All patients presented with recurrent ureteropelvic junction obstruction after open pyeloplasty. Excretory urography and 3-dimensional reconstruction computerized tomography were performed 1 and 6 months after stent insertion. Virtual endoscopy images were obtained at followup due to the need to define ureteral patency. RESULTS: Mean followup was 16 months (range 9 to 24). Wallstent placement was successful and immediate patency was achieved in all cases. During followup 3 patients required no further intervention and the stented ureteropelvic junction remained patent. In the remaining patient stricture recurred 2 months after initial stent insertion due to the ingrowth of scar tissue through the prosthesis. Additional intervention was deemed necessary after placing a longer 6 cm., completely coaxial overlapping metal stent. Virtual endoscopy and excretory urography findings concurred. Virtual endoscopy allows visualization of the stented ureteropelvic junction lumen cephalad and caudal to the prosthesis. It also enables easy navigation within the stent at different angles of view. CONCLUSIONS: The concept of applying metallic stents for ureteropelvic junction obstruction and adjacent adynamic ureteral segments combined with virtual endoscopy is strengthened by the results of this study.     

经内镜金属支架治疗胃出口梗阻的疗效评价

目的 评价经内镜金属支架治疗胃出口梗阻的临床价值.方法 总结1999年3月至2008年1月间复旦大学附属中山医院内镜中心采用内镜金属支架治疗胃出口梗阻56例患者的临床资料.结果 56例患者中男33例、女23例.年龄(65±14)岁;晚期胃窦癌17例,胃癌术后复发15例(其中毕Ⅰ式吻合8例),十二指肠癌4例,壶腹周围癌7例,转移性肿瘤13例.支架置入成功率98.2%(55/56).49例患者(87.5%)在支架置入1～3(2±1)d后开始进流质饮食,进食半流质的时间为4～9(6±2)d;42例(76.4%)患者在支架置入10～16(13±3)d后开始进普通饮食.并发症发生率包括疼痛14.5%、支架移位1.8%和出血25.5%,无穿孔.截至2008年1月20日,53例(96.4%)接受了随访,生存期14～332(139±15)d,中位生存期135 d.支架通畅率94.3%(50/53),有3例患者分别在术后143 d、158 d和190 d出现了再狭窄,通过再次置入金属支架后好转.结论 内镜下金属支架引流术是治疗胃出口梗阻的一种微创、安全、有效的方法.     

经内镜金属支架治疗胃出口梗阻的疗效评价

目的评价经内镜金属支架治疗胃出口梗阻的临床价值。方法总结1999年3月至2008年1月间复旦大学附属中山医院内镜中心采用内镜金属支架治疗胃出口梗阻56例患者的临床资料。结果56例患者中男33例、女23例，年龄（65±14）岁；晚期胃窦癌17例，胃癌术后复发15例（其中毕I式吻合8例），十二指肠癌4例，壶腹周围癌7例，转移性肿瘤13例。支架置入成功率98．2％（55／56）。49例患者（87．5％）在支架置入1～3（2±1）d后开始进流质饮食，进食半流质的时间为4-9（6±2）d；42例（76．4％）患者在支架置入10～16（13±3）d后开始进普通饮食。并发症发生率包括疼痛14．5％、支架移位1．8％和出血25．5％，无穿孔。截至2008年1月20日，53例（96．4％）接受了随访，生存期14～332（139±15）d，中位生存期135d。支架通畅率94．3％（50／53），有3例患者分别在术后143d、158d和190d出现了再狭窄，通过再次置入金属支架后好转。结论内镜下金属支架引流术是治疗胃出口梗阻的一种微创、安全、有效的方法。     

Laparoscopic pyeloplasty for secondary ureteropelvic junction obstruction

PURPOSE: Laparoscopic pyeloplasty has become a viable option for the treatment of select patients with primary ureteropelvic junction obstruction with success rates similar to those of open surgery. However, little has been written on the application of this technique for secondary ureteropelvic junction obstruction. We report the largest series of secondary ureteropelvic junction obstruction managed by laparoscopic pyeloplasty. MATERIALS AND METHODS: Between March 1994 and March 2001, 36 patients underwent laparoscopic transperitoneal pyeloplasty for secondary ureteropelvic junction obstruction. The patients had undergone an average of 1.3 ureteropelvic junction procedures (range 1 to 4) prior to presentation, including cutting balloon retrograde endopyelotomy in 28, antegrade endoscopic endopyelotomy in 7, retrograde endoscopic endopyelotomy in 4, retrograde balloon dilation in 4 and open pyeloplasty in 3. A preoperative diagnosis of recurrent obstruction was confirmed by renal scan in 31 cases, retrograde pyelography in 2 and computerized tomography in 3. Of the 31 patients who underwent spiral computerized tomography angiogram 87% had crossing vessels. Laparoscopic repair comprised dismembered pyeloplasty in 31 cases, Fengerplasty in 3 and flap repair in 2. Postoperative renal scan or excretory urography objective followup was available for all patients at a mean of 10 months (range 3 to 40). Postoperative subjective patient well-being was assessed using an analog pain scale at a mean followup of 21.8 months (range 3 to 85). RESULTS: Average operative time was 6.2 hours (range 2.7 to 10). Average hospital stay was 2.9 days (range 1 to 7). One intraoperative complication occurred, that is bleeding necessitating conversion to an open procedure. Postoperative complications occurred in 8 cases, including anastomotic leakage in 4, and urinary tract infection, pneumonia, atelectasis, fever, bilateral upper extremity weakness and stone formation 2 months postoperatively in 1 each. On excretory urography, furosemide renal scan or the Whitaker test 32 of 36 patients (89%) had a widely patent ureteropelvic junction. Two patients (5.5%) had equivocal radiographic studies but were asymptomatic. In 2 patients the ureteropelvic junction was obstructed by renal scan. One patient had an indwelling stent for renal function deterioration and 1 was asymptomatic. Hence, 34 of the 36 patients (94%) had a reasonable objective response. Overall a 50% or greater decrease in pain was seen in 32 of 36 patients (89%). In the 4 patients with a less than 50% decrease in pain objective renal scans showed an open ureteropelvic junction. As such, the overall success rate of a greater than 50% decrease in pain, a patent ureteropelvic junction and stable or improved function of the affected renal unit was 83% (30 of 36 patients). CONCLUSIONS: For secondary ureteropelvic junction obstruction, laparoscopic pyeloplasty can be performed safely with a success rate comparable to that of standard open pyeloplasty. The patient benefits of laparoscopic ureteropelvic junction repair of secondary ureteropelvic junction obstruction are similar to the benefits of laparoscopic repair of primary ureteropelvic junction obstruction.     

植入镍钛记忆合金支架治疗恶性胆道梗阻的临床分析

目的 评价植入镍钛记忆合金支架治疗恶性胆道梗阻的疗效。方法 对16例恶性胆道梗阻患者。采用经手术及介入方法植入镍钛记忆合金胆道支架。结果 术后1个月内死亡1例，15例黄疸完全解除。随访15例，12例术后平均生存13．1个月。结论 植入镍钛合金胆道支架可提高姑息切除的疗效；对不能切除病灶患者，支架植入可解除黄疸，改善生活质量。     

Regional expression of inducible nitric oxide synthase in the kidney in dogs with unilateral ureteral obstruction

PURPOSE: In the early stage of unilateral ureteral obstruction total renal blood flow increases but medullary blood flow decreases, exacerbating medullary tissue hypoxia. We examined the expression of inducible nitric oxide synthase, a product of a hypoxia sensitive gene, in the cortex and medulla in dogs with unilateral ureteral obstruction for 21 hours. MATERIALS AND METHODS: Hemodynamic and clearance experiments were performed after release of ureteral obstruction in 6 dogs with unilateral ureteral obstruction, followed by Western blot analysis of nitric oxide synthase and immunohistochemistry. RESULTS: Ureteral obstruction raised mean ureteral pressure plus or minus standard error to 35.0 +/- 7.2 mm. Hg. In dogs with unilateral ureteral obstruction mean renal blood flow was 116 +/- 10 ml. per minute, lower than the 213 +/- 22 ml. per minute in sham operated dogs (p <0.01). After unilateral ureteral obstruction release the mean glomerular filtration rate was 9.5 +/- 2.1 ml. per minute, lower than the 27.3 +/- 1.8 ml. per minute in the contralateral unobstructed kidney (p <0.01). Western blot analysis showed that mean nitric oxide synthase/beta-actin in the cortex of the obstructed kidney was 0.04 +/- 0.01 densitometry units, lower than 0.11 +/- 0.02 densitometry units in the unobstructed contralateral kidney (p <0.05). In contrast, mean nitric oxide synthase/beta-actin in the medulla of the obstructed kidney was 1.29 +/- 0.33 densitometry units, greater than the 0.34 +/- 0.03 densitometry units in the unobstructed kidney (p <0.05). Immunohistochemistry revealed that the increased expression of nitric oxide synthase protein was localized to the endothelium of the vasa recta. CONCLUSIONS: Unilateral ureteral obstruction enhances nitric oxide synthase expression in the medulla but not in the cortex. This increased expression in the medulla may be the result of increased medullary hypoxia in unilateral ureteral obstruction, possibly contributing to medullary hyperemia after unilateral ureteral obstruction release.