Application of resonance metallic stents for ureteral obstruction

Study Type – Therapy (case series) Level of Evidence 4

OBJECTIVE

• ? To determine the effectiveness of the Resonance ureteral stent and clarify the risk factors that lead to stent failure. In the present study, we review our clinical experiences using Resonance stent in treating malignant and benign ureteral obstruction.

PATIENTS AND METHODS

• ? Nineteen patients with extrinsic malignant ureteral obstruction (n= 15) and benign stricture (n= 4) were retrospectively evaluated.
• ? All patients had received Resonance stent insertion through antegrade or cystoscopic retrograde approaches. The pre‐insertion and follow‐up interventions included image studies and biochemical tests. The insertion success rate, obstruction patency rate and complications were reviewed.
• ? For categorical variables, the chi‐square test and Fisher’s exact test were carried out to determine associations between variables.

RESULTS

• ? The technical success rate of stent insertion was 84.6%. The mean follow‐up was 5 months (range 1–10.5 months).
• ? Five stents failed to alleviate the obstruction, and the patency rate was 77.3% (17/22).
• ? Patients who had had previous radiation therapy had a lower ureter patency rate in comparison with non‐radiation patients (50% vs 92.3% respectively, P= 0.039).
• ? The 6‐ and 9‐month patency rates were 81.0% with 11 stents and 27.0% with 3 stents, respectively.

CONCLUSIONS

• ? The results of the present study demonstrated that malignant or benign ureteral obstruction could be treated safely and sufficiently with the Resonance metallic stent.
• ? Careful patient selection is critical to achieve successful results.
• ? For malignant ureteral obstruction, previous radiation therapy is a risk factor for stent failure.

     

Outcomes of indwelling metallic stents for malignant extrinsic ureteral obstruction

Objectives

To report the treatment outcomes of patients with extrinsic ureteral obstruction treated with metallic stents and to identify the factors predicting stent failure.

Methods

A total of 52 patients with extrinsic ureteral obstruction as a result of malignancy (66 ureters) were treated with metallic stents (Resonance^®) and included in the study. The median observation period was 118 days.

Results

The median survival time of these patients was 210 days, and the stent patency rate was 86.0% at 6 months and 60.0% at 1 year. Eight (15.4%) patients underwent nephrostomy as a result of stent failure. The occlusion rate of bilateral ureteral obstructed cases was significantly higher than that of unilateral cases. There was no correlation between the preoperative serum creatinine level, causes of ureteral occlusions (compression by tumor, lymph node metastasis, peritoneal dissemination), obstructed site (upper, middle, lower ureter) and stent failure.

Conclusions

Metallic stents are excellent in maintaining patency compared with the conventional stents. Therefore, they can be used as first‐line treatment of malignant ureteral obstructions.     

Stent failure in the management of malignant extrinsic ureteral obstruction: Risk factors

There is still controversy surrounding the indications for performing either a retrograde ureteral stent or percutaneous nephrostomy to manage malignant extrinsic ureteral obstruction (MEUO). We retrospectively analyzed 53 patients who underwent a decompression of MEUO using retrograde ureteral stent. Ureteral stent failure occurred in 18 of 53 patients (34%). Multivariate analysis showed that gastrointestinal cancer as the primary disease, poor preoperative performance status and severe preoperative hydronephrosis were independent predictors of stent failure. Based on the present data, we propose an algorithm for the management of MEUO.     

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.     

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.     

Comparison of efficacy between uncovered and covered self‐expanding metallic stents in malignant large bowel obstruction: a systematic review and meta‐analysis

Aim Insertion of a self‐expandable metallic stent (SEMS) can rapidly relieve colorectal obstruction. This study aimed to compare the efficacy between uncovered and covered SEMSs in the treatment of malignant colorectal obstruction. Method A systematic search in Medline, Embase, the Cochrane controlled trials register and bibliographies of retrieved articles was performed. Randomized controlled trials and other comparative studies comparing uncovered and covered SEMSs for treatment of malignant colorectal obstruction were selected for this systematic review and meta‐analysis. The main outcome measures were technical success, clinical success, tumour ingrowth, tumour overgrowth, early migration (≤ 7 days), late migration (> 7 days), overall complications and the duration of stent patency. Results Compared with covered SEMSs, uncovered SEMSs were associated with a lower late migration rate (relative risk 0.25; 95% CI 0.08, 0.80; P = 0.02), a higher tumour ingrowth rate (relative risk 5.99; 95% CI 2.23, 16.10; P = 0.0004) and a prolonged stent patency (weighted mean difference 15.34 days; 95% CI 4.31, 26.37; P = 0.006). There was no significant difference in technical success, clinical success, tumour overgrowth, early migration, perforation or overall complications between the two groups. Conclusion Tumour ingrowth occurred more frequently in the uncovered SEMS group, while late migration was more common in the covered SEMS group.     

双金属支架对于晚期恶性肝门部梗阻的疗效分析

目的对比内镜双金属支架和塑料支架引流治疗晚期肝门部胆管恶性梗阻的安全性和疗效。方法回顾性分析2007年1月至2013年10月收治的41例采用内镜支架引流治疗的晚期肝门部胆管恶性梗阻的临床资料。结果双金属支架相对于单塑料及双支架有更长的支架通畅时间(187±10 d vs 139±8.8 d;P0.05)。两组之间的术后并发症比较无明显统计学差异。双金属支架可以明显增加肝脏的容积。结论采用内镜双金属支架引流治疗晚期肝门部胆管恶性梗阻是安全可行的,同时可以明显改善肝脏的功能。     

恶性肿瘤致输尿管梗阻治疗方法的选择及疗效观察

目的 探讨恶性肿瘤引起的输尿管梗阻治疗方法的选择并观察其疗效.方法 回顾性分析2011年6月至2013年12月中山大学附属第六医院泌尿外科收治的因恶性肿瘤引起的输尿管梗阻患者32例,行逆/顺行输尿管金属支架置入术或经皮肾穿刺造瘘术,分析治疗过程的临床资料.结果 32例患者均先行逆行输尿管金属支架置入手术,成功17例（53.1％）,失败15例（46.9％）,失败15例患者再行顺行输尿管金属支架置入手术,成功10例（66.7％）,失败5例（33.3％）,失败5例患者最后行经皮肾穿刺造瘘术,全部成功.所有患者治疗后临床症状明显改善,肌酐（Cr）,血尿素氮（BUN）及肾盂分离值三种指标均较治疗前有显著性改善（P＜0.05）.经皮肾穿刺造瘘术患者慢性疼痛发生率显著高于输尿管金属支架置入术患者（P＜0.05）.所有患者均无严重并发症.结论 输尿管金属支架逆/顺行置入术或经皮肾穿刺造瘘术治疗恶性肿瘤引起的输尿管梗阻临床疗效满意,可根据不同情况灵活选择术式.     

经内镜平行法双金属支架引流治疗晚期肝门部胆管恶性梗阻的疗效评价

目的 探讨经内镜“平行法”双金属支架引流治疗晚期肝门部胆管恶性梗阻的可行性、安全性及疗效.方法 采用对照研究的方法,将2011年1月至2012年12月期间收治的69例经内镜置放不同种类和数量支架进行治疗的晚期肝门部胆管恶性梗阻的临床资料进行总结和分析.结果 双金属支架组相对于双塑料及单塑料支架组而言,具有更长的支架平均通畅时间(187±10 d VS.139±8.8 d VS.99 ±3.3 d;P <0.05)和患者平均生存时间(239±10 d vs 191±8.8 d VS.151 ±3.3d;P<0.05),但三组之间的减黄效果和术后并发症的发生率无统计学差异.结论 采用经内镜“平行法”双金属支架引流治疗晚期肝门部胆管恶性梗阻是安全、可行的.其在支架平均通畅时间和病人平均生存时间方面均明显优于塑料支架.     

Initial clinical experience with full-length metal ureteral stents for obstructive ureteral stenosis

OBJECTIVES: Long-term ureteral stenting is used to ensure urinary drainage if a reconstructive approach or a release of an extrinsic obstruction is not possible. In this contribution, a long-term experience with a new full-length, metal indwelling stent is presented. METHODS: Fourteen patients with ureteral obstruction received full metal indwelling stents in 18 collecting systems (benign disease in 5 and malignant disease in 13). Stent placement was performed cystoscopically under fluoroscopic guidance. Follow-up was done every 3 months with ultrasonographic examination, creatinine levels, and a visual analog pain score. RESULTS: Eight stents were removed, whereas eight are still in situ. One patient without stent-related problems died because of progressive rectal cancer 9 months after bilateral stent insertion. Mean stent duration (8 stents still in situ) is 8.6 months, whereas mean stent duration for benign and malignant disease is 11.8 (median 13) and 7.3 (median 6) months, respectively (p<0.05). All removed stents were extracted endoscopically without any problems and had no incrustation except two. Neither migration nor mechanical damage was observed. CONCLUSION: This novel stent is easy to insert and remove. It is an option for patients in which a surgical reconstruction of the obstructed ureter is not possible. Stents have been developed further and are now available in various lengths. This might result in a reduction of problems associated with inadequate stent length and should increase patient comfort and stent durability.     

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。     

Current status of metal stents for managing malignant ureteric obstruction

Obstruction of the ureters caused by extrinsic compression from a primary tumour or retroperitoneal lymph node masses is not unusual in the course of advanced pelvic malignancies. Most of the cases are of gynaecological or gastrointestinal origin, and the situation can be aggravated by peri‐ureteric fibrosis, a long‐term adverse event of previous chemotherapy or radiotherapy. Undoubtedly upper urinary tract decompression and maintenance of ureteric patency, even as a palliative measure, is important in managing these patients. Options for upper tract decompression include percutaneous nephrostomy, retrograde stenting and open urinary diversion. Plastic stents have long been used for managing malignant ureteric obstruction, but their overall success remains limited. Plastic stents often fail to be placed correctly, require regular exchange, and are faced with a high incidence of encrustation and migration. For these reasons plastic stents have been unsuccessful for long‐term maintenance of ureteric patency. To overcome these limitations metal stents were introduced and recently developed in an effort to ensure better long‐term patency of the obstructed ureter, fewer hospital admissions for stent change and better overall quality of life. In the present review the clinical applications of different types of metal stents are discussed, with a specific focus on the latest advances and the future options for managing malignant ureteric obstruction.     

Erythropoietin and its non‐erythropoietic derivative: Do they ameliorate renal tubulointerstitial injury in ureteral obstruction?

Objectives: Pleiotropic effects of recombinant human erythropoietin (EPO) have recently been discovered in many non‐renal animal models. The renoprotective effects of EPO and carbamylated‐erythropoietin (CEPO), a novel EPO which has a small stimulatory effect on hemoglobin, have never been explored in unilateral ureteral obstruction (UUO), a chronic tubulointerstitial (TI) disease model which is independent of systemic factors. Methods: In order to examine the effects of EPO and CEPO treatments on renal TI injury, 36 male Sprague‐Dawley rats, weighing 250–320 g, underwent: UUO without treatment (group 1, n = 12), UUO with EPO (groups 2, n = 12), and UUO with CEPO (group 3, n = 12). EPO and CEPO were injected subcutaneously at a dose of 5000 u/kg to each respective rat at 1 day pre‐UUO and at day 3, 7 and 10 post‐UUO. After days 3, 7, and 14 of UUO, TI injury, collagen, α‐smooth muscle actin (α‐SMA) positive cell, ED1‐positive cell, terminal deoxynucleotidyl transferase (TdT) mediated nick‐end labeling (TUNEL)‐positive cell, and transforming growth factor‐β1 (TGF‐β1) messenger ribonucleic acid (mRNA) were determined. Bcl‐2 expression was also assessed to verify the mechanism of apoptosis. Results: At day 14 UUO caused severe TI injury with a significant increase in collagen, α‐SMA, ED1‐positive cell, TUNEL‐positive cell, and TGF‐β1 mRNA expression. Administration of EPO and CEPO significantly attenuated TI injury, collagen, ED1‐positive cells, and TUNEL‐positive cells. Only CEPO‐treated rats had decreased α‐SMA positive cells and TGF‐β1 mRNA. The expression of Bcl‐2 was demonstrated only in EPO‐treated rats. The hematocrit levels in EPO‐treated rats were higher than the control and CEPO‐treated rats. Conclusions: EPO and CEPO can limit 14‐day UUO‐induced TI injury by reducing inflammation, interstitial fibrosis, and tubular apoptosis.     

Metallic stents in large bowel obstruction: experience in a District General Hospital

INTRODUCTION: Metallic stents are used increasingly in the palliation of malignant large bowel obstruction. Stenting has also been used in the setting of acute obstruction, allowing appropriate patient preparation for an elective colectomy. METHODS: Uncovered metallic stents were inserted using a combined endoscopic/radiological technique in patients presenting with large bowel obstruction. RESULTS: Seventeen patients (10 female, mean age 75.2 years) presented with large bowel obstruction, 14 due to malignancy and 3 secondary to diverticular stricture. Technical success was achieved in 13/17 with clinical success in 12 of these 13. There were no perforations or procedure related deaths. One stented patient had elective surgery. The five patients with clinical/technical failure required emergency surgery. CONCLUSION: The result of our preliminary experience in the use of metallic stents is encouraging. Metallic stents should be available in all hospitals as part of a multimodality approach in treating large bowel obstruction.     

Nickel-titanium shape memory alloy Memokath 051 ureteral stent for managing long-term ureteral obstruction: 4-year experience

PURPOSE: We present our 4-year experience with the thermo-expandable shape memory alloy Memokath 051 stent (Engineers and Doctors of Copenhagen, Copenhagen, Denmark) for managing long-term ureteral obstruction. MATERIALS AND METHODS: We used a nickel-titanium shape memory alloy ureteral stent to treat 28 patients 29 to 86 years old (mean age 59.2). Ureteral obstruction was caused by malignancy in 18 cases and by recurrent benign disease in 10. A total of 37 stents were inserted from November 1996 to November 2000 using general anesthesia. Mean followup was 19.3 months (range 3 to 35). RESULTS: Upper tract decompression was achieved in all cases. Currently 15 stents are functional in 13 patients, while 8 patients died with a total of 13 functioning stents in place. In 7 patients 9 stents were removed for various reasons. There has been no radiological evidence of encrustation to date. No patient has been rehospitalized with stent related sepsis pain or hematuria, resulting in improved quality of life. CONCLUSIONS: This stent seems to provide a significant benefit over conventional Double-J (Medical Engineering Corp., New York, New York) and other metallic stents. Its remarkable thermal memory permits removal, a feature that until recently was not available in any other metallic ureteral stent. Durable and complication-free decompression of the upper tract can be achieved with the Memokath 051.     

The use of triclosan eluting stents effectively reduces ureteral stent symptoms: a prospective randomized trial

Study Type – Therapy (RCT) Level of Evidence 1b What's known on the subject? and What does the study add? Infection, encrustation and ureteral‐stent‐related symptoms (USRS) including pain, urgency and frequency are all major problems associated with stent use. No current ureteral stent or exogenously applied therapy adequately deals with these problems and antibiotic use is ineffective once a bacterial biofilm forms on the device. Triclosan is a broad spectrum antibacterial agent widely used in numerous healthcare products and has been previously shown to reduce inflammation on the skin and in the oral cavity. This study tested a triclosan‐impregnated ureteral stent for its ability to reduce infection, encrustation and USRS. This study shows that while a triclosan‐impregnated ureteral stent cannot reduce infection rates alone compared with antibiotic use, the stent can reduce several USRS including pain during indwelling. This study suggests that the triclosan eluting stent may have a role in treating patients, perhaps in combination with standard antibiotic therapy.

OBJECTIVE

• ? To evaluate the capacity of triclosan‐loaded ureteral stents to reduce stent‐associated bacterial attachment, biofilm formation and encrustation, thereby potentially reducing infection development and other device‐related sequelae.

PATIENTS AND METHODS

• ? Twenty subjects requiring short‐term stenting (7–15 days) were randomized to receive either a Percuflex Plus® non‐eluting stent (control) or a Triumph® triclosan eluting stent.
• ? Control‐stented subjects received 3 days of levofloxacin prophylaxis (500 mg once daily) while Triumph®‐stented subjects did not.
• ? All subjects were assessed for positive urine and stent cultures, stent biofilm development and encrustation.
• ? Following device removal, each subject completed an analogue‐scale symptom assessment questionnaire.

RESULTS

• ? Ureteral stenting was performed after nine ureteroscopic and one extracorporeal shock wave lithotripsy procedure in the control group and eight ureteroscopic and two shock wave lithotripsy procedures in the triclosan group.
• ? No significant differences were observed for culture, biofilm and encrustation between the two groups.
• ? Subjects in the triclosan group reported significant reductions in lower flank pain scores during activity (58.1% reduction, P= 0.017) and urination (42.6%, P= 0.041), abdominal pain during activity (42.1%, P= 0.042) and urethral pain during urination (31.7%, P= 0.049).

CONCLUSIONS

• ? In this study, the use of the Triumph® triclosan eluting stent had no marked impact on biofilm formation, encrustation or infection development in short‐term stented patients.
• ? The Triumph® device led to significant reductions in several common ureteral‐stent‐related symptoms, supporting its use in this patient population.

     

金属内支架治疗消化道恶性梗阻的方法探讨

目的探讨不能手术治疗的消化道恶性梗阻患者，使用金属内支架治疗的方法和疗效。方法回顾分析63例食管癌、6例胰头癌和6例直肠癌所致75例消化道梗阻患者行金属内支架植入术的资料，分析不同部位梗阻行内支架植入的手术操作相似点和不同点及影响术后疗效的因素。结果①各种支架植入术的难度由低到高为食管支架、直肠支架和十二指肠支架植入术；②消化道各部位支架植入术在操作步骤、导管导丝的运用手法、支架直径与长度的选择标准和释放支架的原理方面具有明显的相似性；③十二指肠支架植入在患者术中体位、所用导管型号、医生所受辐射剂量和交换超长超硬导丝的手法方面具有一定特点；④直肠支架植入在患者术中体位、释放支架后1／3时的手法方面具有一定特点；⑤影响术后疗效的主要因素为病变位置特点、患者饮食习惯及疾病发展转归，患者的死亡原因主要为转移和全身衰竭。结论消化道不同部位的金属内支架植入术的操作过程具有高度的相似性，术后并发症的防治亦十分相近；有条件的医疗单位可通过练习依次开展食管支架、直肠支架和十二指肠支架植入术。