Urethral Stent Research Articles

MR‐CT registration using a Ni‐Ti prostate stent in image‐guided radiotherapy of prostate cancer

In image-guided radiotherapy of prostate cancer defining the clinical target volume often relies on magnetic resonance (MR). The task of transferring the clinical target volume from MR to standard planning computed tomography (CT) is not trivial due to prostate mobility. In this paper, an automatic local registration approach is proposed based on a newly developed removable Ni-Ti prostate stent. The registration uses the voxel similarity measure mutual information in a two-step approach where the pelvic bones are used to establish an initial registration for the local registration. In a phantom study, the accuracy was measured to 0.97 mm and visual inspection showed accurate registration of all 30 data sets. The consistency of the registration was examined where translation and rotation displacements yield a rotation error of 0.41° ± 0.45° and a translation error of 1.67 ± 2.24 mm. This study demonstrated the feasibility for an automatic local MR-CT registration using the prostate stent.

Treatment of traumatic penile urethral stricture in a dog with a self-expanding, covered nitinol stent

An 8-month-old castrated male mixed-breed dog was evaluated because of hematuria, stranguria, and dysuria of approximately 2 weeks' duration that developed immediately following elective castration. Results of physical examination, ultrasonography, retrograde double-contrast cystourethrography, and urethroscopy were consistent with a traumatic urethral stricture immediately proximal to the os penis resulting in a partial obstruction of urine outflow. Results of ultrasonographic examination of abdominal organs were considered normal. Digital radiography revealed no evidence of calculi. Balloon dilation of the urethral stricture was performed and was followed by 2 bougienage procedures during the subsequent 2 weeks when clinical signs returned. The owners declined scrotal urethrostomy, and a self-expanding, covered nitinol stent was placed approximately 3 weeks after the initial evaluation, resulting in amelioration of clinical signs. Results of follow-up urethroscopy and contrast cystourethrography 1 year after stent placement revealed a statically positioned, patent urethral stent, although a small number of polypoid mucosal structures were identified distal to the stent and 1 small structure consistent with tissue ingrowth into the stent was identified. Placement of a covered nitinol stent resulted in long-term resolution of clinical signs associated with traumatic stricture of the penile urethra in this young dog. Because the os penis in dogs limits radial expansion of the urethra, its presence may limit the use of stents in this location.

Management of the Detrusor Sphincter Dyssynergia

Detrusor sphincter dyssynergia (DSD) is a disturbance of the normal synergistic coordination between bladder contraction and external urethral sphincter muscles relaxation during voiding. In patients with neurogenic bladder, the urethral sphincter muscle contracts during voiding instead of completely relaxing. This results in alteration of the normal flow and rising of the bladder pressure. The voiding dysfunction and the subsequent dysfunction of the emptying phase of micturition represent a high risk of complications for patients with neurogenic bladder, in relation with high intra-vesical pressure and lack of complete bladder emptying such as: lithiasis, urinary tract infection (UTI), vesico-ureteral reflux, hydronephrosis, and renal failure. Therefore, management of DSD requires a multidisciplinary and careful follow-up to prevent complications. Various physicians should be involved including surgeon, rehabilitation physician, neurologist. Treatment of DSD is a moving field with new emerging approaches and therapies such as botulinum toxin, urethral stent, and promising pharmacological treatment. Therapeutics are often highly specific and should be individually tailored, but with always the same aim: to prevent complications which can impact quality of life, and life expectancy of patients. Here we propose a therapeutic approach to DSD, based on a review of the recent literature and our personal experience. At the end, we try to summarize recommendations for managing DSD in neurogenic bladder.

Nonstented tubularized incised plate urethroplasty with Y-to-I spongioplasty in non–toilet trained children

This study was designed to evaluate the supportive role of spongioplasty during tubularized incised plate (TIP) urethroplasty repair of hypospadias. All non-toilet trained children who underwent TIP repair for primary hypospadias by 1 surgeon over a 30-month period were included in our study. The divergent spongiosa was mobilized off the corpora cavernosa and was rotated toward the midline to wrap the neourethra. A dartos flap was used to cover the neourethra. The neourethra was calibrated immediately after surgery in all patients. A urethral stent was left in place only when difficult calibration was encountered. Complications and cosmetic appearance were documented at last follow-up. Thirty-two consecutive patients with a mean age of 18 (standard deviation [SD] 6) months were included in the study. The defects were distal and mid-shaft in 26 patients (81.3%) and proximal-shaft in 6 (18.8%). No intraoperative catheterization difficulties were encountered and all repairs were nonstented. Antibiotics and anticholinergics were not required. Mean follow-up was 9 (SD 6) months. Urinary extravasation developed in 1 patient (3.1%) on the second postoperative day. A urethral catheter was easily inserted and left indwelling for 5 days. One patient presented 6 days postoperatively with suspected voiding difficulty. Urethral calibration was easily performed excluding any mechanical obstruction. There were no urinary fistulae and reoperation was not required. An excellent cosmetic appearance was achieved in all patients. TIP urethroplasty is a versatile operation that can be performed in almost all cases of penile hypospadias. A nonstented technique for hypospadias repair simplifies postoperative care and obviates the need for antibiotics and anticholinergics. We believe that spongioplasty provides good support to the neourethra and the hypoplastic distal urethra that may facilitate catheterization in the immediate and early postoperative periods, if required. Future controlled study is warranted to further evaluate the role of spongioplasty.

The “perfect” hypospadias repair: Are we there yet?

The “perfect” hypospadias repair: Are we there yet?

Short Term Outcome of Urethroplasty with or without Urethral Stent: A Comparative Study

Urethroplasty is the surgery for Hypospadias. The most common complication of Hypospadias surgery is urethro-cutaneous (U-C) fistula. We designed this study to compare the short term outcome of Urethroplasty with or without urethral stent postoperatively. A total 30 patients of distal penile hypospadias except glnular variety have been studied prospectively in Pediatric Surgery Department of Banga Bandhu Sheikh Mujib Medical University, Dhaka for a period of 20 months, from March 2005 to October 2006. All patients were divided into Group-A (pt with stent) and Group- B (pts without stent). Age ranges of all patients were 2-12 years. After operation no patient developed urinary retention in stented group (Group-A) and 3 patients developed urinary retention which was managed by suprapubic puncture. 5 patients developed urethra-cutaneous fistula in stented group (Group- A) and 2 patients developed fistula in non stented group (Group-B). Calibration was done in all patients after 2 weeks of operation. Before calibration 2 patients came to us with narrow urinary stream of Group-B. After analyzing the result, it was concluded that the short term outcome of Urethroplasty without postoperative urethral stent is better than with stent specially in terms of Urethro-cutaneous fistula. DOI: http://dx.doi.org/10.3329/medtoday.v24i1.14110 Medicine TODAY Vol.24(1) 2012 pp.23-26

MAGPI hypospadias repair: factors that determine outcome

This is a review of our experience with the meatal advancement and glanuloplasty incorporated (MAGPI) hypospadias repair, and we point to some of the factors that determine outcome. We identified all patients who underwent MAGPI repair by a single surgeon over an 8-year period. We performed a retrospective chart review followed by telephone interview to assess parent satisfaction and also functional and cosmetic outcome. Decision to undergo this type of repair was intra-operative, depending on position and mobility of the meatus and the quality of peri-urethral tissue. We identified 48 patients, with a median age of 19 months (8 months-13 years). Position of meatus was glanular (40) or coronal (eight cases). Chordee required correction in 40 % (12/30). Urethral stenting was required in one case. There was no case of fistula, meatal regression, stenosis, or second procedure. A single case of mucosal prolapse was encountered. The majority (47/48) were performed as a day-case. Forty parents agreed to telephone interview. Cosmetic outcome was deemed satisfactory in 95 % (38/40). With regard to unsatisfactory cosmetic outcome, one had a megameatus and the other was aged 13 years and developed a mucosal prolapse. In selected cases, the MAGPI hypospadias repair provide excellent functional and cosmetic outcomes with minimal complications, and it can safely be performed as a day-case procedure.

Thermo-expandable metallic urethral stents for managing recurrent bulbar urethral strictures: To use or not?

ObjectivesTo assess the role of temporary thermally expandable urethral stents in maintaining urethral patency in patients with a recurrent bulbar urethral stricture. Patients and methodsTwenty-three men with a recurrent bulbar urethral stricture after several attempts at direct visual internal urethrotomy (DVIU) and/or failed urethroplasty were managed with a thermally expandable, biocompatible nickel–titanium alloy urethral stent (Memokath® MK044, Pnn Medical, Kvistgaard, Denmark). The stents were applied by a special mounting device via a rigid urethroscope after DVIU. All patients were followed using plain radiography, uroflowmetry and urine analysis every 3months for 1year, and then every 6months. ResultsThe mean (SD) age of the patients was 55.4 (7.3) years and the mean (SD) stricture length was 3.6 (1.2) cm. All patients tolerated the stent, with minimal discomfort in some patients. Four patients (17%) had urinary tract infections, three (13%) had haematuria, three (13%) had obstructed stents due to encrustation, in five (22%) the stent migrated, and two patients had no delayed complications. The mean (SD) follow-up was 17.4 (6.1) months. ConclusionUrethral stenting with nickel–titanium alloy thermally expandable stents can be an acceptable temporary procedure for patients with recurrent bulbar urethral strictures who are unfit for or who refuse urethroplasty. However, they have limitations; the search for an ideal urethral stent continues.

Early Experience With a Thermo-Expandable Stent (Memokath) for the Management of Recurrent Urethral Stricture

PurposeTo report our early experience with thermo-expandable urethral stents (Memokath) for the management of recurrent urethral stricture and to assess the efficacy of urethral stents.Materials and MethodsBetween March 2012 and February 2013, 13 patients with recurrent urethral stricture after several attempts with direct visual internal urethrotomy (DVIU) or failed urethroplasty underwent DVIU with thermally expandable, nickel-titanium alloy urethral stent (Memokath) insertion. Follow-up study time points were at 1, 3, 6, 9, and 12 months after stent insertion. Follow-up evaluation included uroflowmetry, retrograde urethrogram, plain radiography, and urinalysis.ResultsThe mean patient age was 47.7 years (range, 18 to 74 years). The mean urethral stricture length was 5.54 cm (range, 1 to 12 cm). There were six patients with bulbar, four patients with proximal penile, one patient with distal penile, and two patients with whole penile urethral strictures, respectively. The overall success rate was 69% (9/13) and the mean postoperative peak flow rate was 17.7 mL/s (range, 6 to 28 mL/s). Major complications occurred in four patients including one patient (7.7%) with urethrocutaneous fistula induced by the stent and three patients with urethral hyperplasia. The mean follow-up duration was 8.4 months.ConclusionsOur initial clinical experience indicates that thermo-expandable stents can be another temporary management option for recurrent urethral stricture patients who are unfit for or refuse urethroplasty. Distal or whole penile urethral stricture can be factors predicting poor results.

Memokath<sup>TM</sup> Urethral Stents Induce Incontinence in Patients with Urethral Balloon Catheters

With an aging society, elderly patients increasingly require long-term placement of urethral balloon catheters. In this study, we investigated if Memokath(TM) urethral stents, when inserted from the bladder neck to distal to the urethral sphincter in elderly men being treated with urethral balloon catheters, induce incontinence, which would then be managed with adult briefs. Of all outpatients who were being managed with urethral balloon catheters at our institution from September 2011 through March 2012, 4 patients who had had problems with the catheters were included in the study. Exclusion criteria were a performance status of 1 or 2 and the ability to urinate after standard placement of the stent. After application of local anesthesia to the urethra, the Memokath(TM) stent was placed distal to the urethral sphincter under radiographic guidance in all patients. After stent placement, all patients had total incontinence and were catheter-free. Although 2 patients were receiving anticoagulant therapy before the procedure, no intraprocedural or postprocedural anticoagulant-related complications were noted. Memokath(TM) stent-induced incontinence is a safe and effective treatment for patients requiring long-term placement of urethral balloon catheters who are expected to have continuing urination difficulties.

Evaluation of outcome following urethral stent placement for the treatment of obstructive carcinoma of the urethra in dogs: 42 cases (2004–2008)

To evaluate the outcome following urethral stent placement for the palliative treatment of obstructive carcinoma of the urethra in dogs. Retrospective case series. 42 dogs with obstructive carcinoma of the urethra. Medical records for dogs in which a self-expanding metallic stent (SEMS) was used for the treatment of obstructive carcinoma of the urethra were reviewed. Signalment, diagnostic findings, clinical signs before and after SEMS placement, and patient outcome were analyzed. Fluoroscopic images were evaluated to determine the effects of stent size, obstruction length, tumor length, and urethral length and width on the incidence of incontinence or stranguria. Resolution of urinary tract obstruction was achieved in 41 of 42 (97.6%) dogs. After SEMS placement, 6 of 23 male and 5 of 19 female dogs developed severe incontinence, and 1 of 23 male and 1 of 17 female dogs developed stranguria. Stent length, diameter, and location were not associated with incidence of incontinence or stranguria. Median survival time after SEMS placement was 78 days (range, 7 to 536 days). Treatment with NSAIDs before and chemotherapeutics after SEMS placement increased median survival time to 251 days (range, 8 to 536 days). Urethral SEMS placement was an effective palliative treatment for dogs with obstructive carcinoma of the urethra; however, severe incontinence subsequently developed in 11 of 42 (26%) treated dogs. Adjunctive treatment of affected dogs with NSAIDs and chemotherapeutics significantly increased the median survival time.

Outcome of urethral stent placement for management of urethral obstruction secondary to transitional cell carcinoma in dogs: 19 cases (2007–2010)

To determine the outcome in dogs undergoing urethral stent placement for management of urethral obstruction secondary to transitional cell carcinoma (TCC). Retrospective case series. 19 dogs with histopathologically confirmed TCC. Information regarding urethral stent placement and follow-up treatment was obtained from review of medical records. Quality of life assessment was performed with an owner questionnaire. Self-expanding nitinol stents were successfully placed in 17 of 19 dogs; stent placement was not possible in one dog, and another dog was euthanatized 2 days after stent placement, but before discharge from the hospital. Median survival time in 17 dogs following successful long-term stent placement was 78 days (range, 2 to 366 days). Complications following stent placement in 18 dogs included incontinence (n = 7), reobstruction from continued growth of urethral TCC (3), acute reobstruction shortly after the procedure (1), and stent migration (2). Of the 17 owners surveyed, 16 were satisfied with the outcome and would recommend urethral stent placement. The placement of self-expanding nitinol urethral stents was successful in alleviating TCC-induced urethral obstruction and providing good quality of life for most dogs.

The use of octyl cyanoacrylate (superglue) in hypospadias repair including its use as a fixator for urethral stents

BackgroundOctyl cyanoacrylate has been used for many years for simple skin closure, but its use in hypospadias repair and as a urethral stent fixator has not been previously reported. We report our experience. MethodA retrospective study was performed of all children undergoing hypospadias surgery from July 2007 to July 2011. Octyl cyanoacrylate was used for skin closure after placing a few sutures to align the skin edges. No other dressing was used. A urethral stent, if used, was glued to the penis and removed after one week. ResultsSeventy two procedures were performed on 37 patients. Eight distal hypospadias (22%) underwent single stage repair. Seventeen (46%) underwent staged repair for severe hypospadias, and twelve (32%) “hypospadiac cripples” underwent various salvage procedures.One patient (1/72) had partial dehiscence, and one stent dislodged. There were no wound infections. Four (4/25) tabularized urethroplasties developed a fistula (16%). ConclusionOctyl cyanoacrylate is easy to apply on difficult hypospadias contours. It forms a strong, waterproof adhesive bond which separates from epithelial surfaces in 7 to 10days and makes it an effective urethral stent fixator and an ideal dressing for hypospadias surgery.

Résultats à moyen terme du traitement de la dyssynergie vésicosphinctérienne par sphinctérotomie prothétique permanente

The aim of this study was to assess the outcomes of nitinol permanent urethral stents used in detrusor-striated sphincter dyssynergia (DSD) treatment on male patients with a spinal cord injury. We investigated retrospectively all patients treated from 2004 to 2012. A total of 22 patients were included, with an age ranging from 22 to 76 years old. The DSD syndrome was due to spinal cord injury (18) or various spinal cord diseases (four) and treated with a nitinol urethral stent (11 Ultraflex(®) and 11 Mémotherm(®)). Every patient had an urodynamical study. The follow-up reached at least 2 years. The mean follow-up was 56 months (± 14). Complementary procedures after stenting included: five stent prolongation or displacement (mean interval 7.6 months), six bladder neck incisions (12.2 months), three urethrotomy (42 months), ten obstruction treated by laser (47.3 months). Eight patients had a change of their urinary pattern: four underwent ileal conduit diversion, one had a continent urinary diversion, one chose self intermittent catheterization, two were under indwelling catheterization waiting for another treatment. Stent retrieval was either harmful or impossible for four of them. Three patients were free of complementary procedures. Nitinol urethral stent was an effective treatment initially. However, by the third year, urethral stenosis and hypertrophic growth of the urethral mucosa usually require iterative endoscopic procedures (0.31 per patient per year). Patients treated with permanent uretral stent deserve a yearly endoscopic follow-up. Safety and effectiveness of permanent uretral stent compared to surgical sphincterotomy to treat DSD are discussed.

Office Evaluation of Male Patients with Lower Urinary Tract Symptoms

Lower urinary tract symptoms due to benign prostatic hyperplasia (LUTS/BPH) are one of the most common urologic disorders in men. Accurate history-taking and focused physical examination allows us to diagnose the majority of cases. A better understanding of risk factors helps us tailor our treatment and predict outcomes more accurately. Population studies are crucial in our understanding of LUTS/BPH natural history. Temporary prostatic urethral stents that are used for the management of urinary retention may also be used for evaluation of patients with detrusor hypo-contractility. The use of ultrasound to measure intravesical prostatic protrusion (IPP) and the Doppler study for prostate capsular artery resistive index are promising. Near-infrared spectroscopy (NIRS) examines the tissue oxygenation that may be affected by bladder outlet obstruction. The mathematical algorithm needs some fine-tuning, and its reproducibility is debatable. Serum and urinary biomarkers may help us to diagnose the disorder, and more effectively monitor patients' response to therapy. Among all, IPP is clinically more applicable at this time.

Temporary Prostatic Urethral Stenting as a Provocative Tool to Determine Surgical Eligibility in Complex Bladder Outlet Obstructed Patients: Our Initial Experience

Background/Aims: To evaluate the usefulness of a temporary prostatic urethral stent to determine which complex surgical patients would benefit from definitive surgical management of their benign prostatic hyperplasia. Methods: We retrospectively analyzed our benign prostatic hyperplasia database and identified all patients that received at least one temporary prostatic urethral stent between April 2008 and December 2010. Results: Forty Spanner^TM stents were placed in 20 patients. Mean age was 78.1 years and prostate size was 62.1 cm³. Urinary retention was present in 60% (12/20) of patients. No statistically significant changes in mean maximal flow rate, average flow rate, and post void residual was noted. Seven patients (35%) did well with the stent and progressed to definitive surgical management whereas 10% of the cohort (2/20) leaked urine with the stent in place and subsequently went back to catheter management. Another 30% (6/20) were unable to tolerate the stent while 1 patient passed away unrelated to the stent. Conclusions: The use of the temporary prostatic urethral stent provided a good provocative test that enabled patients to experience what their voiding status would be if they were to undergo definitive surgical management.

Catheter-associated urinary tract infection

Catheter-associated urinary tract infection (CAUTI) is the commonest nosocomial infection worldwide. Here we review the recent advances in the prevention of CAUTI. After more than 30 years, new guidelines were issued in 2008-2011 by the Infectious Diseases Society of America, Society for Healthcare Epidemiology of America, Healthcare Infection Control Practices Advisory Committee and European Association of Urology. These guidelines addressed novel technologies such as silver alloy or antimicrobial coatings on catheters, hydrophilic catheters, urethral stents, use of sealed catheter-tube junctions and antiinfective bladder irrigation. In addition, multiple trials have been published recently on the reduction of inappropriate urinary tract catheterization. Numerous strategies have been developed to reduce the incidence of CAUTI but few have proven effective. Reducing the inappropriate use of catheters and development of novel technologies targeted against these increasingly multidrug-resistant pathogens may be useful in the prevention of CAUTI in our vulnerable patients.

Evaluation of the Anti-migration Effect of Barbed Prostatic Stents: In Vitro Study in Urethra-mimicking Bovine Pericardium Phantoms

This study was designed to compare the migration rates of covered stents with eight, four, and zero barbs in urethra-mimicking bovine pericardium models. Three types of polytetrafluoroethylene-covered retrievable self-expandable prostatic stents, with eight, four, and zero barbs, were tested in bovine pericardium models, consisting of normal saline-filled acrylic containers with tubes at both ends and a replica of the human urethra. The barbs were 2mm in length and projected 60° toward the urinary bladder. The anti-migration force (AMF) and resistance force against stent removal (RFSR) were measured by an automatic push-pull gauge system at a fixed rate (2mm/s). Significant differences in AMF among the three stent types were detected (P<0.001). Median AMF was far greater for eight-barbed than for four-barbed stents (11.96 vs. 7.55N, P=0.003). For stent removal, the difference between 4- and 8-barbed stents were not significant in median static (5.54 vs. 6.08N, P=0.15) or sliding (prostatic urethra, 5.32 vs. 5.59N, P=0.65; membranous urethra, 7.78 vs. 8.57N, P=0.364) RFSR. No perforations or scratched traces were observed during removal of these stents. The inclusion of eight barbs projecting 60° toward the urinary bladder were not only effective against stent migration in this model but suggests that these stents may be suitable for the treatment of prostatic urethral strictures without severely irritating the tissue. However, whether these results translate into living urethral tissue is unclear, necessitating further studies.

Does the type of urinary diversion affect the result of distal hypospadias repair? A prospective randomized trial

The purpose of this review is to evaluate different techniques in urinary diversion and urethral stenting in hypospadias surgery. The surgical procedure included 192 tubularized incised plate (TIP) repairs for distal penile hypospadias. The patients were prospectively randomized into three groups: In group A, a urethral catheter was used as a stent and for diversion of urine (63 patients); in group B we use no urethral stenting (63 patients), only a suprapubic catheter; and in group C we use a suprapubic diversion and we put a small catheter in the anterior urethra only (66 patients). The urethral catheter was removed in group A at the 6th-7th postoperative day and in group C the urethral stent was removed at the 3rd-4th postoperative day. The suprapubic catheter was removed in both groups B and C at the 7th-9th postoperative day. All patients received an injection of antibiotics in the morning of the operation and daily until the day of catheter removal. All of the operations were performed by the same surgeon. The mean ages of our patients were 3, 5, and 5 years in groups A, B, and C, respectively. The mean hospital stay was 5 days (3-8). Follow-up ranged from 8 to 48 months (mean of 21.5 ± 10.1 months). Bladder spasm was observed in 33% of our patients in group A while there were no cases of spasm in the other two groups with a statistically significant difference (p < 0.05). Fistula was reported in eight patients (12.7%) of our urethral catheter group A, while it was observed in three patients (2.3%) of our suprapubic diversion groups B and C with a statistically significant difference between the two groups (p < 0.05). Meatal stenosis was reported in eight patients in group B (12.7%; nonstented group) versus three patients of both groups A and C (2.4%; stented groups) with a statistically significant difference (p < 0.05). Suprapubic diversion is an important step in hypospadias repair as it provides a better success rate with a significantly lower rate of occurrence of fistula. However, the addition of a stent in the anterior urethra to suprapubic diversion avoids the development of meatal stenosis and also avoids the bladder spasm observed with a urethral catheter.

Outcome of Dual Flange Metallic Urethral Stents in the Treatment of Neuropathic Bladder Dysfunction After Spinal Cord Injury

To review the results of metallic urethral stents used in patients with neuropathic bladder dysfunction after spinal cord injury (SCI). In a rehabilitation unit for SCI and stroke in Cape Town, South Africa, we performed a case note review of dual flange Memokath stents placed from March 2008 until October 2011. Stents were placed rather than performing an external sphincterotomy in selected patients. With the patient under deep general anesthesia, a thermosensitive expandable metallic stent was positioned over the internal and external urethral sphincters. In total, 33 stents were placed in 28 male patients. SCI was cervical in 23 patients and thoracic in 5. Average follow-up was 18 months (range 1-40 months, median 18 months). The most common indications were repeated catheter blockage in eight patients and urinary tract infection in six. The average time from SCI to stent insertion was 79 months (range 1-468 months, median 21 months). Severe autonomic dysreflexia was present in 17 cases before stent placement and in 7 after stents were placed (P=0.003). Stents failed in 15 patients (45%) and were removed. The most common reason for failure was stone formation. Comparing the group of patients with stents lasting >20 months (n=11) to the group with stent removal before 20 months (n=10), the mean time between SCI and stent placement was 31 vs 119 months (P=0.057). Medium term results (up to 27 months) were significantly influenced by earlier stent placement (P=0.0484). One major complication was stent migration that caused an urethrocutaneous fistula.