Outcome after treatment of detrusor-sphincter dyssynergia by temporary stent

OBJECTIVES: To evaluate follow-up treatments used after treatment of detrusor-sphincter dyssynergia (DSD) by a temporary urethral sphincter stent. MATERIALS AND METHODS: Between February 1994 and June 2003, 147 men with a mean age of 41.3+/-14.4 years were treated by temporary urethral stent inserted across the external sphincter for DSD. The underlying neurologic disease was quadriplegia in 85 cases, multiple sclerosis in 24 cases and paraplegia in 21 cases. A Nissenkorn (Bard) stent was used in 130 cases and a Diabolo (Porgès) stent was used in 17 cases. All patients were either unable to or they refused to perform intermittent self-catheterization. DSD was demonstrated by urodynamic studies in every case. RESULTS: The mean duration of temporary stenting was 10.15+/-16.07 months. After temporary stenting, 92 patients were treated by permanent stent (Ultraflex, Boston Scientifics), 7 started intermittent self-catheterization, 12 had repeated changes of the temporary stent, 4 had an indwelling catheter, 3 underwent cystectomy with non-continent diversion, 2 were treated by endoscopic sphincterotomy, 1 was treated by bladder neck incision, 1 was treated by neuromodulation and 1 was treated by cystostomy. Fifteen patients were lost to follow-up. Two patients died during follow-up (not related to DSD). CONCLUSION: After treatment of DSD by a temporary urethral sphincter stent, 70.7% of patients subsequently require a permanent urethral sphincter stent. This period allows selection of patients unlikely to benefit from permanent urethral sphincter stent.     

Urethral stent for the treatment of detrusor-sphincter dyssynergia: evaluation of the clinical, urodynamic, endoscopic and radiological efficacy after more than 1 year

PURPOSE: We studied the intermediate-term clinical, urodynamic, endoscopic and radiological efficacy of the Ultraflex urethral stent (Boston Scientific Co., Boston, Massachusetts) for the treatment of detrusor-sphincter dyssynergia (DSD) in spinal cord injured patients. MATERIALS AND METHODS: A total of 47 consecutive men presenting with DSD due to spinal cord injury (39) or various spinal cord diseases (9) were treated with the Ultraflex stent. DSD was demonstrated by urodynamic assessment with electromyographic recording of the striated urethral sphincter muscle activity. RESULTS: Postoperatively, all patients voided by reflex. The number of patients with symptomatic postoperative urinary tract infection decreased significantly (p <0.001). Urodynamic assessment (mean followup +/- SD 2.2 +/- 1.3 years) showed reduction of mean peak detrusor pressure from 65.7 +/- 27.8 to 46.4 +/- 28.8 cm H2O (p <0.005) and reduction of mean residual urine from 231.6 +/- 168.1 to 70.3 +/- 85.6 ml (p <0.0005). Mean urethral closing pressure was markedly reduced from 73.9 +/- 40.9 to 23.8 +/- 25.1 cm H2O (p <0.0005). Mean endoscopic followup was 1.7 +/- 1.1 years. Mean percentage of epithelialization was 90.8% +/- 19.7%, and no obstructive granulation tissue or stone encrustation was observed inside the stent. On ultrasound signs of hydronephrosis persisted in only 1 of 8 patients. There were no immediate postoperative complications. Complementary bladder neck incision was performed in 21% of patients. CONCLUSIONS: The Ultraflex stent appears to be effective for intermediate-term treatment of DSD on the basis of clinical, urodynamic, endoscopic and radiological parameters.     

Memokath stents for the treatment of detrusor sphincter dyssynergia (DSD) in men with spinal cord injury: the Princess Royal Spinal Injuries Unit 10-year experience

STUDY DESIGN: Medical records review. OBJECTIVE: To assess the effectiveness of the Memokath (Engineers and Doctors A/S, Denmark) thermosensitive stent as a 'nondestructive' means of reducing bladder outlet resistance by treating detrusor sphincter dyssynergia (DSD) of neurogenic bladder dysfunction associated with spinal cord injury. SETTING: Spinal Injuries Unit, Sheffield, England. METHODS: A medical records review was performed to examine our experience of Memokaths over the last 10 years. During this time, 29 patients with spinal cord injury (17 tetraplegic and 12 paraplegic) underwent stenting of the external urethral sphincter either for prevention of dysreflexic symptoms, high residual urine volumes and subsequent urinary tract infection (UTI) or for protection of the upper tracts. RESULTS: A total of 33 stents were inserted into 29 men (25-77 years) with suprasacral spinal cord injury. Initial results showed that the Memokath was effective in almost all for relief of dysreflexic symptoms and elimination of DSD on pressure flow urodynamics. However, to date, 30 of the 33 stents have been removed. The overall mean working life of the Memokath was 21 months. Four stents were removed electively and 23 for complications, which included stent migration (seven) and blockage (14). Single-ended stents were more prone to migration, which was rare after 1 year (1-13 months, median 3 months, mean 5.5 months). Stent blockage by encrustation or prostatic ingrowth did not occur before 12 months (12-45 months, median 30, mean 27.9 months). CONCLUSIONS: In selected patients, temporary, thermo-expandable (Memokath) stents are effective in the treatment of DSD. The 'working life' of a Memokath stent is 21 months; however, complications do occur which may necessitate removal. Our overall experience with Memokath stents was disappointing. In future, Memokath stents will only be inserted after careful consideration in patients with prior 'failed' transurethral sphincterotomy or with caution in patients suitable for reconstructive surgery.     

The use of the Memokath stent in the treatment of detrusor sphincter dyssynergia in spinal cord injury patients: a single-centre seven-year experience

AIMS: A retrospective analysis of our seven-year experience with the Memokath urethral stent for the treatment of detrusor sphincter dyssynergia (DSD) in spinal cord injured (SCI) patients. PATIENTS AND METHODS: Twenty five patients with SCI underwent rhabdosphincter Memokath stent insertion. The mean age was 45.5 years (range 32-65 years). The level of injury was cervical in 14 and thoracic in 11 patients. All patients were shown to have neurogenic detrusor overactivity with DSD associated with high detrusor pressures and incomplete emptying on pre-operative video-cystometrograms (VCMG). The Memokath stent was inserted using a standardized protocol. Follow-up assessment included blood chemistry, ultrasound scan (upper tracts and residual urine) at one and three months after insertion, and a follow-up VCMG at six months. The pre-operative and six-month post-operative VCMG results were analysed by the paired t-test and p value <0.05 was taken as significant. RESULTS: There was a significant reduction in maximum detrusor pressure, duration of contraction and residual urine volume (p<0.05) on the VCMG six months after insertion of the stent. At present six patients have a Memokath stent in situ at a mean of 34.7 months (range 6-86 months). Nineteen stents were removed for several reasons at a mean of 20.3 months (range 0.25-41 months). These include, exacerbation of autonomic dysreflexic symptoms (n=3); stent migration (n=7); encrustation and stone formation (n=5); incomplete bladder emptying without obstruction (n=3); entrance into fertility program (n=1). CONCLUSION: The Memokath stent is safe, easy and quick to insert with minimal trauma to the urethra. It is effective in the management of DSD and decreasing the detrusor pressure and residual urine volume in SCI patients. Moreover the ease of its removal in a non-traumatic fashion makes this stent an attractive option when patients are still contemplating the method of bladder management, in those wishing to be involved in fertility program and in recently SCI patients who may recover some manual dexterity to perform clean intermittent self-catheterisation. It must be remembered that this is a temporary stent, as our study clearly shows that the majority are removed within two years of insertion.     

Feasibility of a temporary urethral stent through the striated sphincter in patients in the early phase (6 months) of spinal cord injury

OBJECTIVE: To assess the feasibility of a temporary urethral stent through the striated sphincter in patients in the early phase (before 6 months) of spinal cord injury (SCI) in a department of neurological rehabilitation. METHODS: Fourteen consecutive men with SCI with urinary retention within 6 months after SCI were prospectively treated. Thirteen patients were tetraplegic (C2 to C7) and 1 was paraplegic. All patients were managed with indwelling catheters (10) or intermittent catheterization (4). The Nissenkorn polyurethane urethral stent was inserted across the external sphincter under local anesthesia for an anticipated 4-month duration. RESULTS: No perioperative complications were encountered. Hospital mean stay at the urological department was 1.9 days (range 1-4 days). All patients had good emptying of the bladder (residual urine less than 100 ml) and were free of all types of catheterization. Five stents had to be repositioned in the first 2 weeks, 1 was removed for obstruction at 2.5 months. There was no lithiasis, no upper urinary tract alteration, no symptomatic infection nor local discomfort during follow-up. At a mean of 3.7 months after implantation, 10/14 (71.5%) patients chose sphincterotomy by permanent urethral stent and 4 had stent removal for learning of self-intermittent catheterization (3) and indwelling catheter (1). CONCLUSIONS: The temporary sphincter stent is a new, feasible and reversible technique to manage neuropathic bladder dysfunction in the early phase after SCI. A randomized study on intermittent catheterization should be conducted. It should consider patients' and nursing caregivers' evaluations.     

Airway stents in management of tracheal stenosis: have we improved?

BACKGROUND: Airway stenting is an alternative approach for relieving airway stenosis when lesions are inappropriate for single-stage reconstruction. The aim of this study was to present our experience using airway stent in the management of patients with tracheal stenosis. METHODS: This study retrospectively reviewed 45 patients who underwent airway stenting during a 2-year period. Between June 2002 and August 2004, 45 patients underwent rigid bronchoscopy for tracheal stenosis using an Ultraflex stent (Microvasive; Boston Scientific, Boston, MA, USA), Hood stent (Hood Laboratories, Pembroke, MA, USA) and Montgomery T-tube (Boston Medical, Westborough, MA, USA). Clinical improvement, intraoperative, early and late postoperative complications were evaluated. RESULTS: Ultraflex stent was used in 14 patients, Hood stent in 9 and Montgomery T-tube in 22. The overall clinical improvement was 95.5%. Four per cent of the patients (2/45) had intraoperative complications, 8.8% (4/45) had early postoperative complications and 51% (23/45) had late postoperative complications. No significant difference was determined between stent type and complication rates. CONCLUSION: Rigid bronchoscopic insertion of airway stents for tracheal stenosis is a safe and effective procedure. No difference exists between stent type and clinical improvement, intraoperative and early and late postoperative complications.     

Complication of benign tracheobronchial strictures by self-expanding metal stents

OBJECTIVES: Self-expanding metal stents are used to palliate benign strictures. We examined the complications of this approach. METHODS: Between 1997 and 2002, we observed recurrent airway obstruction and extension of benign inflammatory strictures after the placement of tracheobronchial Microvasive Ultraflex stents and Wallstents (Boston Scientific Corp, Natick, Mass), in 10 patients with postintubation strictures and 5 with other indications; all but 1 patient were referred to us. Patients with tracheal (9), subglottic (1), combined tracheal and subglottic (3), and bronchial (2) strictures had been treated with covered and uncovered Wallstents (6) and Microvasive Ultraflex stents (9). RESULTS: After stent insertion, stricture and granulations within previously normal airway were seen in all patients. New subglottic strictures resulting from the stent caused hoarseness in 4 patients. A bronchoesophageal fistula was found in 1 patient at presentation and a tracheoesophageal fistula in another during extraction of a Wallstent. Primary surgical reconstruction, judged to have been feasible before wire stent insertion in 10 patients, was possible after stenting in only 7 and failed in 2. Palliative tubes were placed in 60% (9/15). Self-expanding metal stents may lengthen luminal damage, incite subglottic strictures, and cause esophagorespiratory fistula in inflammatory airway strictures. The injury is severe, occurs after a short duration of stenting, and precludes definitive surgical treatment or requires more extensive tracheal resection. CONCLUSION: The current generation of self-expanding metal stents should be avoided in benign strictures of trachea and bronchi.     

Outcome of dual flange metallic urethral stents in the treatment of neuropathic bladder dysfunction after spinal cord injury

Abstract Purpose: To review the results of metallic urethral stents used in patients with neuropathic bladder dysfunction after spinal cord injury (SCI). Patients and Methods: 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. Results: 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.     

Experience with Ultraflex expandable metallic stents in the management of endobronchial pathology

BACKGROUND: Experience with Ultraflex expandable metallic stents (Micro-invasive, Boston Scientific, Watertown, MA) in the management of endobronchial pathologies leading to airway compromise is reported. METHODS: Between January 1999 and August 2000, twenty-eight expandable metallic stents were inserted into 25 patients (7 men and 18 women; median age, 65 years) who presented with respiratory distress. Each patient had comorbid medical conditions or end-stage malignancy that precluded formal surgical repair. Seventeen patients had intrinsic airway obstruction, 5 had extrinsic compression, 2 had a tracheal tear, and 1 had a tracheoesophageal fistula. Stents were inserted through a bronchoscope under direct vision. Eighteen patients received tracheal stents alone (1 of these patients received two tracheal stents), and 5 patients received bronchial stents only. Two patients received a tracheal and a bronchial stent. Twenty-one stents were covered and seven were uncovered. RESULTS: All patients had successful stents with restoration of airway patency and closure of tracheal defects. One patient developed a respiratory infection early after the operation. Follow-up bronchoscopy confirmed satisfactory stent position in each patient. Late complications included sputum retention, halitosis, and granulation tissue formation. CONCLUSIONS: Ultraflex expandable metallic stents should be considered in the management of airway compromise in selected patients for whom formal surgical repair is inappropriate or contraindicated.     

Medium-term follow-up after deployment of ultraflex expandable metallic stents to manage endobronchial pathology

Background

Between March 1997 and March 2004 we deployed 80 Ultraflex metallic expandable stents (Boston Scientific, Waterson, MA) in 69 patients under direct vision using rigid bronchoscopy. We report our medium- to long-term experience in patients for whom these stents were deployed.

Methods

To date 15 patients have been followed for more than 1 year (median 41 months, range 12 to 83 months) after stent deployment. Indications for stenting in these patients were neoplasia (5), stricture (5), airway malacia (1), iatrogenic tracheal tear (1), and compression from an aortic aneurysm (1), a right interrupted aortic arch (1), and a right brachiocephalic artery aneurysm with tracheomalacia (1). Ten tracheal stents (9 covered, 1 uncovered) and 10 bronchial stents (8 uncovered, 2 covered) were inserted, and 5 patients received two stents.

Results

Five of these patients experienced no long-term problems. Complications included troublesome halitosis (5), which was difficult to treat despite various antibiotic regimes; granulation tissue formation above and below the stent that was successfully treated with low-power Nd:YAG laser therapy (7); and metal fatigue (1). We did not encounter stent migration.

Conclusions

We conclude that Ultraflex expandable metallic stents have an important role in the management of selected patients with diverse endobronchial pathologies and are well tolerated in the long-term. Although associated granulation tissue can be successfully treated with Nd:YAG laser, halitosis can be a difficult problem to address.     

Insertion of self-expanding metal stents for malignant dysphagia: assessment of a simple endoscopic method

AIM: To assess the efficacy, safety and long-term results of self-expanding metallic prostheses, placed using an entirely endoscopic method, for the relief of dysphagia in oesophageal carcinoma. PATIENTS AND METHODS: A consecutive series of 50 patients (30 men, 20 women), aged 43-91 years (median, 75 years) underwent stent placement (Ultraflex Stent, Boston Scientific, Watertown, MA, USA) under general anaesthesia without fluoroscopic control. RESULTS: Stent placement was successful in all patients. Swallowing improved from dysphagia score 4, 3 or 2 to score 1 (or 0) in all patients available for long-term follow-up (excluding two patients who died, and two who had resection, in the immediate post-stenting period). There were two early deaths that were, or could have been, procedure-related and one early complication, in addition to technical problems in 6 cases, all early in the series. Seven patients required endoscopic laser treatment, on 13 occasions, subsequently for tumour in-growth or over-growth. Of the 46 patients with long-term stents in situ, 36 patients died with a median survival time of 4 months (range 10 days to 24 months). At the time of writing, 10 patients are still alive with a median survival of 4 months (range 1-11 months). CONCLUSIONS: Self-expanding metallic stents provide rapid, safe and effective relief of dysphagia. They can provide long-term palliation (> 1 year) with endoscopic laser treatment for recurrent in-growing/over-growing tumour. Fluoroscopic control is not necessary for the safe and accurate placement of such stents.     

Sphincterotomy and the treatment of detrusor-sphincter dyssynergia: current status,future prospects

STUDY DESIGN: Literature review of current treatment options for detrusor-sphincter dyssynergia (DSD) in spinal cord injury. OBJECTIVES: To review the outcomes and complications associated with external sphincterotomy and to summarise the results and complications of alternative treatment options for detrusor-sphincter dyssynergia in spinal cord injury. In addition, we propose a potential alternative future drug treatment for external sphincter dyssynergia based upon recent research on the neuropharmacology of the external urethral sphincter. SETTING: The National Spinal Injuries Centre, Stoke Mandeville Hospital, Aylesbury, UK. METHODS: Medline search from 1966 to 2002 using the words 'external sphincterotomy', 'detrusor-sphincter dyssynergia' and 'neurogenic bladder combined with surgery'. RESULTS: While external sphincterotomy is an effective treatment for DSD, a significant number of men following this procedure continue to have high intrarenal pressures, recurrent urinary infection or troublesome autonomic dysreflexia and a worryingly high proportion demonstrate persistently raised leak point pressures, putting them at subsequent risk of renal damage. Alternative treatments for external sphincter dyssynergia include urethral stents and balloon dilatation, both of which are effective. However, over the long term stents can undergo encrustation and there remains a definite risk of stent migration necessitating stent removal or replacement. Balloon dilatation of the external sphincter is associated with a risk of subsequent stricture formation. Intraurethral Botulinum A toxin seems to be effective though there have been no large randomised studies comparing it against placebo. However, it is not a durable treatment option and it has not found a common place in the treatment of DSD.There is now a considerable amount of experimental data from both animal and human studies to suggest that nitric oxide (NO) is an important physiological inhibitory neurotransmitter in the urethral sphincter, mediating relaxation of the external urethral sphincter. The potential role of sphincter NO augmentation for treatment of DSD is discussed. CONCLUSION: External sphincterotomy remains the mainstay of treatment for urodynamically significant detrusor-sphincter dyssynergia, but in recent years a number of effective, alternative treatment options have become available. While at present there is no effective systemic drug treatment, recent research into external sphincter neuropharmacology suggests that systemic or topical augmentation of external sphincter NO may provide an effective method for lowering sphincter pressure.     

Epidural catheters can facilitate laparoscopic placement of ureteral stent: description of a technique

AIM: To introduce a novel technique for laparoscopic placement of ureteral stent and to investigate the safety and effectiveness of this new method. METHODS: Fourteen patients underwent laparoscopic placement of ureteral stents with the technique. The stent was indwelled with an epidural catheter, delivered to the operative field, and placed through the ureteral incision into the renal pelvis and bladder, respectively. The stent was then secured with pincers, while the epidural catheter was removed. RESULTS: With this method, the ureteral stent insertion is very convenient and time saving (the mean time for inserting a stent was 2.7 min). The stents were successfully inserted into 13 patients once. One patient underwent insertion of the stent twice intraoperatively. Thirty days after the operations, none of double-J stents had migrated out of the renal pelvis or bladder. CONCLUSIONS: This technique is reliable and effective in laparoscopic ureteral operations. Its use should be generalized in laparoscopic ureteral operations.     

Permanent external striated sphincter stents in patients with spinal injuries

Nine patients with complete quadriplegia underwent external striated sphincter stenting with the Wallstent in place of an external striated sphincterotomy. Although suprapubic catheters were placed to provide an outlet should problems develop with the stent, they were successfully removed within 6 weeks in all but 1 patient. Complete bladder emptying with reduced voiding pressures was achieved, together with a significant reduction in the duration of hyper-reflexic contractions. Epithelialisation of the stent was almost complete within 3 months and intermittent catheterisation or endoscopy (and resection) is possible through the stent. Although this is a preliminary report of this new technique, it is hoped that sphincter stenting will provide a rapid, safe and effective method of treating high pressure hyper-reflexia and detrusor sphincter dyssynergia in quadriplegic patients.     

Coated v noncoated ureteral metal stents: an experimental model.

PURPOSE: The purpose of the present study was to compare the standard metal stents with internally and externally coated metal stents in the pig model. MATERIALS AND METHODS: In nine female pigs weighing between 25 and 30 kg, the metal stents were randomly placed in either the right or left ureter, for a total of 18 stented ureters. Six ureters were stented with a Wallstent (Schneider, Zurich, Switzerland), six with a Passager stent (Boston Scientific, Natick, MA, USA), and six with a Corvita endoluminal graft (CEG) (Boston Scientific, Natick, MA, USA). Patency was examined by nephrostotomography 24 hours and 21 days after the initial procedure. RESULTS: Free flow of urine through the stents into the bladder was revealed in all ureters with the exemption of four cases where a Passager stent migrated into the bladder, jeopardizing ureteral patency. The Wallstent generated mild inflammation with metaplasia of the urothelium; the CEG a more pronounced inflammatory response in the adjacent ureter; and the Passager stent severe inflammatory reaction with necrosis of the urothelium. The sections of the Wallstents revealed the presence of a mild polypoid reaction adherent to the internal surface of the devices. The coated stents showed no tissue ingrowth through the lining material into the ureteral lumen, and thus, the urothelium was compressed beneath the prostheses. CONCLUSIONS: Our experimental results suggest that the standard Wallstent generates less inflammation of the surrounding tissues than coated stents. The coated stents have the advantage of minimal tissue ingrowth but have a tendency to migrate toward the bladder.     

Anesthetic management of tracheobronchial stent insertion and extracorporeal lung assist (ECLA)

We experienced eight cases of general anesthesia for tracheobronchial stent insertion. All stents were Ultraflex stent (Boston Scientific, Tokyo), and they were inserted guided by bronchofiberscopy under general anesthesia. Anesthesia was induced with patients under spontaneous breathing, and we inserted a tracheal tube or a laryngeal mask airway. Anesthesia was maintained with propofol and sevoflurane. In four cases with severe tracheobronchial stenosis, we used venovenous extracorporeal lung assist (ECLA) before general anesthesia induction. Oxygenation during stent insertion was well-maintained in all patients. We must evaluate the severity of tracheobronchial stenosis preoperatively. In high risk cases anticipated of airway obstruction, ECLA should be used for safe anesthetic management.     

Incontinence, intermittent self-catheterization and the artificial genitourinary sphincter

Although the artificial genitourinary sphincter is ideally suited for incontinent patients who can empty the bladder completely, we have observed 22 patients with artificial sphincters who also perform intermittent self-catheterization to augment bladder emptying. No cuff erosions have occurred to date, with 11 patients on intermittent catheterization for more than 30 months. In patients who will require intermittent self-catheterization after sphincter implantation the cuff should be placed around the bladder neck. We believe that patients with sphincteric incontinence and decreased bladder contractility resulting in excessive residual urine volume are reasonable candidates for use of the artificial sphincter with intermittent self-catheterization.     

In-vivo evaluation of flow characteristics of novel metal ureteral stent

PURPOSE: To characterize the flow of a novel ureteral stent composed of a nickel-cobalt-chromium-molybde-num alloy and compare it with flow in a standard ureteral stent. MATERIALS AND METHODS: Six 6F Resonance stents and six 6F standard Black Beauty ureteral stents were placed in six Yucatan minipigs, with each pig serving as its own control. Flow assessment was performed on all stents via a nephrostomy tube delivering a standard rate of 0.9% saline at 35 cm H(2)O. Flow studies on the standard stents encompassed extraluminal (i.e., lumen of stent occluded with a guidewire), intraluminal (i.e., ureter secured to stent with a constricting suture), and combined (i.e., open lumen without constricting suture) flow. In the Resonance stent, only combined and intraluminal flow could be addressed, as there is no access to the lumen of this stent. RESULTS: With the Resonance stent, intraluminal flow was much greater than combined flow, with mean values of 5.15 mL/min and 2.50 mL/min, respectively (P = 0.057; SD = 7.73). Intraluminal flow was similar to combined flow in the 6F standard stent, with mean values of 7.34 mL/min and 7.30 mL/min, respectively (P = 0.88; SD = 1.76). The standard stent had significantly greater combined flow than the Resonance stent (P = 0.023) but not intraluminal flow (P = 0.247). Of note, whereas it was possible to occlude the 6F standard stent completely with a ureteral ligature (i.e., no guidewire placed in the lumen), it was not possible to occlude the Resonance stent regardless of how tightly the suture was tied. CONCLUSION: The Resonance metal alloy stent provides less overall flow than a standard stent. However, under circumstances of extrinsic ureteral compression sufficient to occlude a standard stent (e.g., extrinsic compression plus an internal guidewire), the metal stent continues to provide satisfactory drainage.     

Externally coated ureteral metallic stents: an unfavorable clinical experience

OBJECTIVE: The purpose of the present study was to evaluate the use of externally coated stents in patients with malignant ureteral obstruction. MATERIALS AND METHODS: We have prospectively evaluated 16 patients, 10 men and 6 women, with malignant ureteral obstruction treated successfully by placement of Passager metal stents (Boston Scientific, Natick, MA, USA) bypassing the stricture. Mean patient age was 65.6 years (range 62-78 years). Ureteral patency was confirmed 24 and 48 hours by injection of contrast material through the nephrostomy tube, and after patency confirmation the nephrostomy catheter was removed. RESULTS: All stents were positioned successfully, and the postoperative course was uneventful. In 13 cases (81.2%) the prostheses finally migrated into the bladder hindering overall ureteral patency (mean time of migration: 1.5 months). Patency was achieved in the remaining ureters (n=3), during the follow-up period (mean: 8 months, range 6-16 months), without any need for further intervention. CONCLUSION: The inappropriate anchorage and the increased ureteral peristalsis are the main causes of migration towards the bladder, thus, minimizing the usefulness of this stent for the treatment of ureteral strictures.     

How to manage acute urethral false passage due to intermittent catheterization in spinal cord injured patients who refused insertion of an indwelling catheter

PURPOSE: Acute urethral false passage is an important complication of clean intermittent catheterization in spinal cord injured patients. Temporary urethral stenting with an indwelling catheter is generally an excellent conventional therapeutic option to treat patients with acute false passage. However, how can acute false passage be managed in a patient who refuses insertion of an indwelling catheter? MATERIALS AND METHODS: For 3 years 5 male patients with acute urethral false passage due to catheterization refused urethral stenting because indwelling catheter insertion would prevent sexual intercourse. We placed a nitinol prostatic stent successfully in the false urethral passage in all 5 patients. The stents were left in place for 3 to 6 months. RESULTS: The stent migrated in 1 patient and it was replaced. During a retention period of 3 to 6 months all patients continued clean intermittent catheterization without any difficulty and achieved sexual intercourse. On urethral cystoscopy we observed that all false passages disappeared without a gross tissue reaction. The stents were then removed without any complications. During a mean followup of 11.8 months (range 4 to 25) none of these patients had another false passage. All continued to perform clean intermittent catheterization without any further difficulty. CONCLUSIONS: Temporary placement of a removable endourethral stent is a safe and effective method for managing acute urethral false passage in patients on clean intermittent catheterization who refuse insertion of an indwelling catheter. This approach makes further clean intermittent catheterization possible and improves patient quality of life.