Colonization of internal ureteral stent and bacteriuria

To demonstrate the infection rates, colonization rates following the internal ureteral stent placement; the correlation of indwelling time with the infection, bacterial colonization and the value of urine culture to identify colonizing bacteria One hundred and forty-eight stents of 146 patients were evaluated for the bacteriuria and colonization after internal ureteral placement average 8.6 weeks according to the indication. All patients were ambulatory and were examined in an outpatient clinic. Urine culture and 1 cm of proximal and distal ends was taken for culture for bacterial evaluation. The rate of colonization is 33, 50 and 54% when indwelling time is less than 4 weeks, 4–6 weeks and more than 6 weeks, respectively. Urine culture can detect colonization in 69%. Colonization was not found if the indwelling time was less than 2 weeks. Escherichia coli, Enterobacter and Pseudomonas spp. were the most common colonized organisms. Colonization is common if the indwelling time is more than 2 weeks, urine culture can detect colonization in about two to three of the patients. Even if the culture is negative, prophylactic antibiotic that cover gram-negative and gram-positive organisms should be administrated when the patients require further procedures.     

Knotted ureteral stent: a rare complication of ureteral stent usage

The use of ureteral stents has become a routine urological practice. There are many different complications with ureteral stent use. One rare complication is knotting, which can be a very difficult condition to treat. We report a case in which a complete knot was found in the proximal part of an indwelling ureteral stent with a proximal ureteral stone.     

Extended double-J ureteral stent

Continent forms of urinary diversion using intestinal segments are becoming increasingly common. As this new treatment modality evolves, our instruments and mechanical devices are likewise evolving and adapting to the changing needs placed on them. We have used a new type of double-pigtail ureteral catheter in patients requiring continent urinary diversion. It allows stenting of the ureteral-intestinal anastomosis and safeguards against urinary leak or extravasation; at the same time the catheter is accessible to the outside for easy replacement, manipulation, and radiographic evaluation. The catheter has also shown to be useful for other purposes such as uretero-neo-cystostomy. This is particularly important in the pediatric population where repeated cystoscopy for stent removal or manipulation can be a significant drawback.     

Anatomic, functional, and pathologic changes from internal ureteral stent placement.

The anatomic, hydrodynamic, functional, and pathologic changes associated with unilateral internal ureteral stenting were evaluated in 20 female canines. Selective glomerular filtration rates (GFR) were measured with technetium 99m diethylenetriamine pentaacetic acid (DTPA) renal scans (N = 14) prior to and several weeks after unilateral internal stent placement. Cystometry and cystography were done at weekly intervals to determine if reflux occurred and to measure the intravesical pressure to produce this reflux (N = 16). Ureteral lumenal capacities of mid 6-cm ureteral segments of stented and unstented ureters were compared. The mid-ureteral lumenal volumes were three times greater in the stented ureters (p < 0.002). There were no significant differences in the selective GFR before and after stenting. Low-pressure vesicoureteral reflux occurred at a mean intravesical pressure of 13.7 cm of water and was present in 84.6 percent (11/13) of the canines whose stents did not migrate or obstruct from encrustation. There were no significant alterations in serum chemistries or blood counts. Fluoroscopic imaging also showed ineffective ureteral peristalsis. This study confirms that internal ureteral stents cause vesicoureteral reflux and significant lumenal dilation without altering renal function.     

Double-ended pigtail ureteral stent: useful modification to single end ureteral stent.

A newly created ureteral stenting catheter of double-ended pigtail design is introduced. The pigtail design at both ends maintains the catheter in place by serving as a solid anchoring device, both intravesically and within the renal pelvis; upward or downward migration of the stent is thus prevented. It is designed also to minimize trigonal irritation. The catheter can be introduced easily either cystoendoscopically or through a percutaneous antegrade route, or by a combination of both methods. It offers the additional advantage of being readily available from an inexpensive stock source; it may be quickly and easily custom made and shaped for any ureter by the physician immediately prior to its insertion. It thus avoids having to have premanufactured, more expensive ureteral stents of different lengths. Open surgery for upper urinary tract decompression can thus be avoided.     

Role of color-coded Doppler sonography in the assessment of internal ureteral stent patency.

OBJECTIVE: To evaluate the role of color-coded Doppler sonography (CCDS) in the assessment of internal ureteral stent patency. PATIENTS AND METHODS: We compared micturating cystography (MC) and CCDS in 48 patients with internal ureteral stents. Forty-five of these patients had pyelocaliectasis on renal sonography. RESULTS: In all of the 48 patients, the distal end of the internal ureteral stent could be seen sonographically in the bladder. The color images of 30 patients showed typical flow from the distal holes of the stent. Micturating cystography demonstrated patency of the stents in 36 patients. The two procedures showed the same results in 42 of 48 patients. Six patients had no detectable flow by CCDS, but the MCs showed patency of the stents. CONCLUSION: The CCDS is a valid noninvasive method for the assessment of internal ureteral stent patency with a sensitivity of 100%, a specificity of 83%, a positive predictive value of 67%, and a negative predictive value of 100%.     

Noninvasive assessment of patency of internal ureteral stent: role of colour Doppler ultrasound

OBJECTIVE: To compare colour Doppler ultrasonography (CDU) and retrograde cystography in the assessment of the patency of internal ureteral stents. PATIENTS AND METHODS: Thirty-two patients with 33 internal ureteral stents were evaluated for patency of the internal ureteral stent using both CDU and retrograde cystography. Real-time ultrasonography and CDU were performed before retrograde cystography. Stent patency was defined as seeing flow from the distal end of the stent in the urinary bladder or iodinated contrast in the renal pelvis. The two investigators had no prior knowledge of the other's results. After completion of both investigations, stent patency was proved by direct inspection of the stent after removal. RESULTS: Both investigations showed the same result in 27 of the 33 stents. Stent patency was found if either investigation was positive. The accuracies of retrograde cystography, CDU and both were 73%, 79% and 85%, respectively. CONCLUSIONS: CDU is a noninvasive method with high accuracy. Detection of flow at the distal end of the stent is helpful, but absence of flow may or may not indicate an obstructed stent and further investigation should be performed.     

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.     

Advances in ureteral stent technology

This review focuses on technological advances and relevant research related to ureteral stents. The importance of physical and chemical biomaterial type, biocompatibility, material coatings such as hydrogels, and infection related to indwelling ureteral stents are discussed. Recent in vitro and in vivo research has focused on materials that will reduce encrustation and bacterial biofilm formation. The adsorption of antimicrobials onto devices holds promise of reducing infection rates, but multidrug resistant bacteria, short leaching times and adverse side effects make it essential that alternative strategies be investigated. Just so, encrustation limits the long-term use of urinary materials, and a better understanding of factors involved in encrustation are needed to reduce the problem.     

Double pigtail ureteral stent.

Problems encountered in patients with ureteral obstruction treated with single pigtail polyethylene ureteral catheters (stents) were largely due to positioning difficulties, proximal migration, and irritation of the bladder mucosa by the distal flange. A new, double pigtail modification of this self-retained internal stent limits migration, minimizes irritant side effects, and facilitates endoscopic, percutaneous, and open surgical positioning over a springwire guide. These stents provide useful alternative to surgical correction or external tube diversion in many patients with complicated ureteral obstruction.     

输尿管内支架管的简易拔除方法探讨

目的 探讨不用膀胱镜便可取出输尿管内支架管的方法。方法 行肾及输尿管上端手术时，将双Ｊ管与肾造瘘管用丝线连接，术后将两者一并拔出。行膀胱及输尿管下端手术时，用丝线将双Ｊ管与导尿管相连，并使丝线保留一定长度，术后拔导尿管时，剪断丝线尾并妥善固定至所需时间，通过牵拉丝线拔出双Ｊ管。结果 用上述方法顺利取出双Ｊ管８４例，无明显并发症，均不需要膀胱镜。结论上述方法不用膀胱镜即可拔出双Ｊ管，操作简单，减少病     

Minimally invasive ureteral stent retrieval

PURPOSE: We developed a minimally invasive (noncystoscopic) method for retrieving ureteral stents. MATERIALS AND METHODS: A total of 30 consecutive patients underwent placement of a ureteral stent with a stainless steel bead attached to its distal end. The stent was later removed by a urethral catheter with a rare earth magnet attached to its proximal end. RESULTS: In 29 of the 30 patients the stent with the attached bead was removed without difficulty or patient discomfort. The single failure occurred in a patient with a large median prostate lobe. CONCLUSIONS: Minimally invasive, nonendoscopic ureteral stent retrieval was achieved in 97% of patients. The attractive force of the magnet for the bead was sufficient to attract and extract the stent. No adverse effects of the procedure or the stainless steel bead were noted. This magnet retrieval system is a feasible, simpler and less invasive alternative to cystoscopic retrieval of ureteral stents.     

Extracorporeal shock wave lithotripsy monotherapy of 'stoned' internal ureteral stent in children. Case report

A case of ESWL treatment, as monotherapy, of a 'stoned' ureteral stent in a 12-year-old boy was described. Two years previously, the patient had pyelolithotomy with staghorn stone removal, and double-J stent was left indwelling intraoperatively. The patient was lost for follow-up for 2 years, when he had multiple stone formation adherent to the whole length of the stent. Four ESWL sessions were required before the stent was freed for removal.     

Exchange/retrograde ureteral stent set

Once in position, ureteral stents are relatively inaccessible. A ureteral stent set was developed that allows for retrograde study of the collecting system or exchange of the stent with or without the assistance of a cystoscope. This has proved to be useful for opacification of the collecting system during extracorporeal shock wave lithotripsy or percutaneous nephrolithotomy, or after ureteroscopy.     

DSA导向下逆行双“J”输尿管支架置换术

目的观察DSA导向下逆行双"J"输尿管支架置换术的有效性和安全性。方法选取因输尿管梗阻行DSA导向下逆行双"J"输尿管支架置换术患者21例。收集患者的临床资料,分析输尿管支架置换术的技术要点、成功率及并发症。结果共置换输尿管支架32例次,技术成功率96.88%(31/32)。术后均未见严重并发症,轻度并发症包括尿道灼痛(32/32,100%)、出血(21/32,65.63%)、尿路感染(5/32,15.63%)。结论 DSA导向下逆行双"J"输尿管支架置换术是一项安全、有效的操作技术,值得推广;膀胱内抓捕输尿管支架和经导丝引入新支架是该技术操作的关键。