The role of airway stents in the management of pediatric tracheal, carinal, and bronchial disease.

OBJECTIVE: A variety of stents are available to aid in the management of complex tracheal, carinal and bronchial stenoses. We reviewed our multi-institutional experience with airway stents in children. METHODS: Thirty-three children (age, 13 days-18 years) from four institutions have had a total of 40 stents placed to aid in the management of complex airway stenoses. Three stent types were utilized: 29 silastic stents, five expandable metal stents and six customized carinal stents (four patients had two stents and one patient had four stents). Thirty children had tracheal stents, six children had bronchial stents, and two infants had carinal stents (three children had stenting of more than one area and two had stenting of all three locations). Twenty-eight patients (age, 5 months-18 years; mean, 8.06 years; SEM, 1.13 years) had stents placed after a variety of airway reconstructive procedures. Four underwent stenting in a non-operative setting and one as preoperative stabilization. RESULTS: Twenty-seven patients survived. One patient died early due to bleeding. Five patients died late: two due to bleeding, one from mediastinitis, and two patients with functional airways died late from unrelated problems. Complications are related to stent type and location. Carinal stents can migrate; several techniques are available to help manage this problem. Wire stents are essentially non-removable requiring periodic dilation. Silastic stents stimulate granulation tissue formation requiring periodic bronchoscopic removal. CONCLUSION: Tracheal stenting can aid in the management of pediatric airway problems. Complications are common, but can be managed with appropriate intervention.     

Metallic stents as a new therapeutic procedure for urinary tract obstruction

Tube stents are widely used to achieve internal urinary drainage in the urology field. Recently, in an attempt to improve upon metallic stents, these stents were introduced for use in the obstructed urethra and ureter. We review the current indications and devices for internal urinary drainage using metallic stents. In recent years, intraprostatic metallic stents have been established as a minimally invasive alternative treatment for benign prostatic hyperplasia (BPH). Appropriate patient selection and optimal stent positioning are required. However, intraprostatic metallic stents represent a useful option to BPH therapy for high operative-risk patients. Only limited data exist concerning patency rates and the efficacy of stent treatment of ureteral obstruction, and the indications for the implantation of metallic stents in these patients is controversial. The efficacy of metallic stents in this situation is not clear, but some investigators suggest that the implantation of metallic stents in obstructed ureters may be safely and effectively performed in patients with incurable malignancies.     

Endoscopic biliary drainage in patients with pancreatic cancer

Obstructive jaundice is a common clinical sign in patients with pancreatic cancer. 52% of all patients with a potentially resectable pancreatic cancer suffer from painless obstructive jaundice. There are no prospective studies showing a beneficial effect of preoperative drainage in patients with resectable pancreatic cancer. Morbidity (53%) and mortality (15%) in patients without preoperative biliary drainage are not significantly different from those who had endoscopic drainage preoperatively (morbidity 41%; mortality 15%). However, there are some logistic reasons for preoperative drainage, especially if surgery is delayed. In cases of nonresectable pancreatic cancer endoscopic drainage for palliation of obstructive jaundice is the method of choice. The decision between metallic and plastic stents for palliation is based on expected survival time and quality of life. Implantation of metal stents is the method of choice in patients with life expectancy exceeding six months. Scheduled three months exchange of plastic stents is recommended to avoid complications. After a six months interval about 70% of patients with scheduled exchange are without symptoms, compared to about 40% of patients who had exchange of plastic stents on demand. Scheduled three months exchange of plastic stents leeds to a patency rate of plastic stents comparable to those of metallic stents.     

Stenting and interventional radiology for obstructive jaundice in patients with unresectable biliary tract carcinomas

Together with biliary drainage, which is an appropriate procedure for unresectable biliary cancer, biliary stent placement is used to improve symptoms associated with jaundice. Owing to investigations comparing percutaneous transhepatic biliary drainage (PTBD), surgical drainage, and endoscopic drainage, many types of stents are now available that can be placed endoscopically. The stents used are classified roughly as plastic stents and metal stents. Compared with plastic stents, metal stents are of large diameter, and have long-term patency (although they are expensive). For this reason, the use of metal stents is preferred for patients who are expected to survive for more than 6 months, whereas for patients who are likely to survive for less than 6 months, the use of plastic stents is not considered to be improper. Obstruction in a metal stent is caused by a tumor that grows within the stent through the mesh interstices. To overcome such problems, a covered metal stent was developed, and these stents are now used in patients with malignant distal biliary obstruction. However, this type of stent has been reported to have several shortcomings, such as being associated with the development of acute cholecystitis and stent migration. In spite of these shortcomings, evidence is expected to demonstrate its superiority over other types of stent.     

Endoprostatic stents for management of benign prostatic hyperplasia

Endoprostatic stents have been developed for relieving bladder outlet obstruction secondary to benign hyperplasia of the prostate. The stents are designed either for permanent or for temporary placement. The short-term temporary stents of various biostable and biodegradable polymers are needed after minimally invasive therapy of prostate with heat. The temporary stents are a management option, whereas the permanent stents are a treatment option. Permanent stents offer immediate relief and their sustained results for 4-7 years make them ideally suited for medically compromised patients.     

Endoscopic biliary stenting: Plastic stent or expandable metallic stent?

Since its introduction 1979, endoscopic biliary stenting has become the method of first choice to treat cholestasis in malignant or benign biliary obstuction or leakage of biliary fistulas. The success rate of endoscopic biliary stenting generally exceeds 90% and procedure-related complications are rare. Although metal stents are becoming more popular, plastic stents are still the first choice. Their major drawback is occlusion with sludge mediated by bacteria. Pharmaco-chemical measures failed to prevent occlusion. With Teflon material and a 10-French stent, stent exchange rates were reduced to 15% in patients with malignant biliary obstruction, the shape without sideholes showing the best results. Stent exchange is easily feasable. Metal stents are expensive and more difficult to handle. Occlusion with sludge is rare, but patency is limited by tumor ingrowth. Metal stents may be indicated in selected patients, such as those with recurrent stent occlusion causing cholangitis. If only a small-caliber prosthesis (7-Fr) can be placed (e.g. in Klatskin tumor) metal stents may have a longer patency than plastic stents. Metal stents should not be used in benign biliary obstruction because these stents are not removable.     

Recent advances in ureteral stents

PURPOSE OF REVIEW: Conventional ureteral stents, which have been in use for almost 30 years, are undergoing several changes in materials, designs and purposes of use. RECENT FINDINGS: Recent advances in ureteroscopes reduced the numbers of double-J insertions. In addition, because of the frequent failures of the double-J stents in malignant obstructions of the ureter coiled metal stents, metal coil-reinforced stents and large-caliber self-expanding stents are being developed for such patients. In the near future, a new application will be stent-based drug delivery. SUMMARY: The conventional double-J stents and the concept of ureteral stenting is undergoing several changes. New generation stents will allow the physician to choose better-fitting stents according to the needs of the individual patient.     

Stented versus nonstented ureteroileal anastomoses: is there a difference with regard to leak and stricture?

We reviewed the clinical histories of 362 patients (711 renal units) who had undergone ileal conduit diversion. Stents were used in 126 patients (247 renal units) and were not used in 236 (464 renal units). The stented group was divided further into 95 patients (186 renal units) with silicone single J stents and 31 (61 renal units) with some other type of stent. The over-all incidence of urine leakage was 1.7 per cent (6 of 362 patients). The over-all incidence of stricture was 3.9 per cent (11 without and 3 with stents). No leak occurred among the 126 patients in whom a stent was used. None of the 95 patients in whom silicone single J stents were used had stricture. If stents are to be used, we recommend silicone single J stents because of their satisfactory performance to date.     

Bacterial colonization of ureteral stents.

OBJECTIVES: The aim of this study was to assess the frequency of bacterial stent colonization and stent-associated bacteriuria, and to evaluate the significance of urinary cultures for identification of colonizing microorganisms. METHODS: A total of 93 ureteral stents from 71 patients were examined: 9 patients with permanent ureteral stenting due to malignant ureteral obstruction (27 stents), and 62 patients with temporary ureteral stents (66 stents). RESULTS: Bacteriuria and bacterial stent colonization were found in all patients with permanent stents. In patients with temporary stents, colonized stents were found in 69.3% (43/62), mainly in combination with sterile urine (45.2%, 28/62). Mean indwelling times did not differ between patients with sterile urine and sterile stents (11.8 days) and patients with sterile urine and colonized stents (11.2 days). Prophylactic antibiosis in 42/62 temporarily stented patients did not reduce colonization rates compared to patients without antibiotics (70 vs. 65%). Enterococci were the bacteria most frequently cultured from urine and stents. CONCLUSIONS: In the present study, ureteral stent colonization rates were 100% in permanently and 69.3% in temporarily stented patients. Antibiotic prophylaxis did not prevent stent colonization and should not be routinely administered. Since urinary cultures correctly identified all colonizing microorganisms in only 21%, removal/replacement and bacteriologic evaluation of ureteral stents may be necessary in case of urosepsis.     

Use of endotracheal silicone stents for relief of tracheobronchial obstruction.

In this article we describe our initial experience with bifurcated and longitudinal silicone stents that can be inserted entirely endoscopically. A total of 10 patients were stented; half had upper airways obstruction resulting from malignant disease and half had anastomotic obstruction after single-lung (3 patients), double-lung (1 patient), or heart-lung transplantation (1 patient). All patients derived immediate relief of life-threatening stridor. Stents were in place for between 5 days and 2 1/2 years (mean, 232.9 days). In the patients with malignant disease, the stents have provided effective relief from stridor for the remainder of their lives. In the transplant recipients, the medium-term results are encouraging, with the stents providing effective relief from stridor, although the longitudinal stents have been associated with distal migration, requiring that the stents be replaced on up to five occasions. The stents have not been associated with infection in the nonimmunosuppressed patients, and during the relatively short follow-up period there has been no tissue reaction to the material.     

输尿管镜术后双J管引流无效原因分析

目的　总结输尿管镜手术后应用双J管引流无效的原因。　方法　回顾性分析 2 0 0 0年 6月至 2 0 0 3年 3月输尿管镜手术后放置双J管引流的 3972例患者拔管前进行追踪观察。男 2 184例 ,女 1788例 ,共放置双J管 4 6 35例次 ,其中经尿道逆行放置者 3138例次 ,经皮肾造瘘口顺行放置者14 97例次。　结果　全组双J管引流无效者 115例次 ,占 2 .4 8%。常见原因有严重腔外梗阻、严重输尿管石街、严重输尿管狭窄和支架管过期留置。　结论　严格掌握输尿镜手术及双J管放置适应证和术后紧密追踪观察是减少发生输尿管镜术后双J管引流无效的关键     

Anaesthesia for endobronchial intervention and tracheobronchial stents

There is an increasing use of large airway stents for non-malignant disease processes. As advances in stent development and manufacture are made, there are more patients being treated with airway stents. Stenting can be short term or long term and can be used for the management of large airway obstruction where surgery carries both morbidity and mortality.Pre-operative assessment is particularly important and may determine which of the wide range of techniques that have been used is most appropriate for the individual case.The anaesthetic management of patients with stents already in situ is becoming more important as the number of patients with stents increases. There are some specific pitfalls and problems associated with anaesthesia and these are reviewed.     

Lethal complications of standard self-retaining ureteral stents in patients with ileal conduit urinary diversion

While standard commercially available pigtail ureteral stents are used commonly in the obstructed patient, particularly when metastatic disease has been identified, our recent experience suggests caution in the use of such stents for patients with ileal conduits. Rapid obstruction of these stents occurs with unacceptable frequency, which has resulted in urosepsis and death, and they do not appear to be cost-effective even for palliation. Although these standard pigtail stents have physical properties that allow easy placement by angiographic wire guidance, they are not to be recommended. Safe internal ureteral diversion in patients with an ileal conduit awaits further evolution in stent technology.     

Ureteroscopic removal of retained ureteral Double-J stents

At the Lahey Clinic Medical Center, Double-J stents are placed primarily for management of patients with calculi. They are used before extracorporeal shock-wave lithotripsy (ESWL) of large renal calculi or bilateral ESWL treatments and after ureteroscopic instrumentation or removal of calculi. They are also used for palliative urinary diversion for patients with ureteral obstruction secondary to pelvic cancer. Fluoroscopy with C-arm guidance is the standard radiologic technique employed for manipulation of all calculi and insertion of stents. Results have been good with the use of these stents, but in 3 patients the rigid ureteroscope was required to remove a retained Double-J stent.     

Do ureteral stent diameter and length or patient demographics play a role in stent encrustation?

IntroductionRetained ureteral stents may constitute a technical challenge. The purpose of this study was to analyze the patient population with retained ureteral stents with regards to stent sizes to better understand if these factors could play a pivotal role in their encrustation.MethodsAfter institutional review board approval, we retrospectively analyzed the data of patients who underwent multimodal surgical procedures for the removal of retained ureteral stents from 2010–2018. The primary outcomes analyzed were ureteral stent length and diameter, location of stent placement, and patients’ demographics as potential etiologies for encrustation.ResultsWe included 30 patients with 32 encrusted ureteral stents and 37 patients with 46 forgotten non-retained ureteral stents. Indications for stenting included urolithiasis, malignancy, pregnancy, ureteral stricture, and ureteropelvic junction obstruction. Stent diameters ranged from 6–8.5 Fr. Stent lengths ranged from 22–30 cm, and multilength stents were used too. Smaller diameter stents were less likely to be retained when compared to larger diameter stents (>6 Fr) (p=0.002). Overall stent length was not found to be significant (p=0.251); however, the difference in stent surface area differed by over 1 cm (p<0.001). Patients who were uninsured were more likely to have retained stents (p=0.003). Patients who reside with longer commuting distance to the main academic medical center were more likely to have retained stents (p=0.010).ConclusionsRetained ureteral stents could be avoided. Taking into consideration ureteral anatomical variation among patients, smaller diameter stents and smaller surface area may prevent encrustation. Uninsured patients with farther distance to seek medical care and females are the most at risk.     

Advances in ureteral stent design

BACKGROUND AND PURPOSE: Ureteral stents are widely used in patients with urologic disorders. This review critically evaluates the recent literature, providing an update on advances in the development and design of stents. METHODS: A thorough MEDLINE and PubMed literature search on ureteral stents was performed, and all pertinent articles were reviewed in detail. This review was formulated on the basis of these articles, encompassing both basic science and clinical aspects of advances in ureteral stent design. RESULTS: The advances in development and design have been directed primarily toward decreasing stent-related morbidity such as discomfort, bladder irritability, infection, encrustation, and the need for an additional cystoscopic procedure to remove the stent. In recent years, there have been many significant advances in the design of ureteral stents, including tapered distal ends, and construction, such as magnetic, biodegradable, and tissue-engineered materials. CONCLUSIONS: There are many different bulk materials and coatings available for the manufacturing of ureteral stents, many of which are new. However, the ideal biomaterial has yet to be discovered. With ongoing research in this area, further advances in ureteral stent design will continue to improve outcomes for patients who require stents. Future advances are likely to include drug-coated stents, drug-eluting stents, and localized stenting techniques such as endoluminal gel paving.     

Surgical bypass versus metallic stent for unresectable pancreatic cancer

With the development of interventional radiology and endoscopy, the practice of inserting expandable metallic stents for malignant jaundice has become widespread. Many studies have compared surgical bypass with polyethylene stents, or metallic stents with polyethylene stents. However, few data are available on the comparison of surgical bypass and metallic stents. The aim of this study was to compare the patient's postprocedure course and the cost performance of surgical bypass and metallic stents in patients with unresectable pancreatic cancer. The parameters analyzed were the rates of procedural and therapeutic success, duration of hospital stay, prevalence of early and late complications, cost performance, and prognosis. The rates of procedural and therapeutic success were excellent with both palliative treatments. With surgical bypass, there was a low prevalence of late complications, but duodenal obstruction sometimes occurred in patients without gastric bypass. With metallic stents, there was shorter hospitalization and lower cost, but a higher prevalence of late complications. Stent occlusion tended to occur in patients with uncovered metallic stents. There was no difference in the prognosis between the two palliative treatments. Thus, in consideration of the poor prognosis of pancreatic cancer, in patients with unresectable pancreatic cancer, insertion of covered metallic stents would be preferable to surgical bypass, because of the subsequent short hospitalization and the low cost. On the other hand, in patients with a relatively long expected prognosis, or in those with existing duodenal obstruction, biliary bypass with gastrojejunostomy may provide an advantage. Received: February 13, 2001 / Accepted: May 11, 2001     

冠脉支架患者非心脏手术的围手术期处理

背景 近三十年来,心脏冠脉支架患者日益增多,此类患者在接受非心脏手术时其围手术期将面临特殊挑战.目的 现将重点讨论支架血栓的病理生理以及冠脉支架患者非心脏手术围手术期的处理策略.内容 冠脉支架患者为预防支架内血栓的发生,通常接受由阿司匹林和氯吡格雷为主要药物的双联抗血小板治疗,其疗程为裸金属支架bare metal s...     

Extracorporeal shock wave lithotripsy for large renal calculi: the role of ureteral stents. A randomized trial

Ureteral stents reduce complications after extracorporeal shock wave lithotripsy (ESWL*) and contribute to successful stone passage. However, some reports note complications that are attributed to indwelling ureteral stents. We randomized 64 patients with large renal calculi (stone burden more than 200 mm.2) for in situ treatment or treatment with a prophylactically inserted stent. We used a 6Ch round stent with single-coiled ends or a triangular shaped stent with double-coiled ends. Patients were treated with a Siemens Lithostar lithotriptor. After 3 months we evaluated the results of treatment and post-ESWL morbidity. Of the in situ group (23 patients) treatment complications consisted of fever in 3, pyelonephritis in 1 and steinstrasse in 3. After 3 months 8 patients (35%) were free of stones. Of the stented population (41 patients) treatment complications consisted of fever in 7, pyelonephritis in 1, steinstrasse in 6 and bladder discomfort in almost half of the patients. Stent calcification and stent migration were also seen in 7 and 10 patients, respectively. Calcified stents had been in situ longer than noncalcified stents. The round stents migrated and calcified more often than the more rigid triangular stents. After 3 months 18 of the stented patients were stone-free (44%). We conclude that ureteral stents do not reduce post-ESWL complications. They are clearly associated with morbidity and do not improve stone passage markedly. Therefore, patients with a stone burden of more than 200 mm.2 should be treated in situ without auxiliary stenting.     

输尿管镜钬激光碎石术后双J管相关并发症的危险因素

目的探讨输尿管镜钬激光碎石术后双J管相关并发症的危险因素。方法于2009年3月至2010年12月前瞻性持续纳入病例,对可能引起并发症的因素进行单因素和多因素统计分析。结果纳入257例患者,术后并发症的发生率为83.2%。多因素分析显示,尿路刺激症的危险因素为双J管远端经过膀胱中线、留置26 cm双J管、双J管留置超过4周;排尿困难的危险因素为留置26 cm双J管;腰痛的危险因素为留置24、26 cm双J管。镜下血尿的危险因素为留置26 cm双J管、留置超过4周;急性尿失禁的危险因素为双J管远端经过膀胱中线。结论多数并发症与双J管长度过长有关。选择合适长度的双J管可能是减少术后相关并发症最重要的因素。