Long-term clinical results and quality of life after insertion of a self-expanding flexible endourethral prosthesis

First experiences with the Spanner™ temporary prostatic stent for prostatic urethral obstruction

OBJECTIVES

To assess the ease of insertion and removal of a temporary prostatic stent (the Spanner™) following the use of a prostatic urethral measuring device (the Surveyor™).

PATIENTS AND METHODS

Patients with bladder outflow obstruction or urinary retention awaiting definitive surgery were fully consented. Data were collected pre- and post-insertion and patients followed-up until definitively treated.

RESULTS

16 patients had the Spanner inserted following use of the Surveyor. All insertions were uncomplicated. 14 patients were able to void satisfactorily immediately post-insertion with a mean Qmax of 15.0 ml/s and post-void residual of 51.3 ml. No symptomatic infection was reported. The stents stayed in situ for a median of 10 days. 12 stents were removed prematurely due to severe symptoms or retention. A total of 12 stents had to be removed endoscopically.

CONCLUSIONS

The Spanner is easy to insert. Stent removal via the retrieval suture has been difficult necessitating the use of endoscopy in the majority of cases. Possible causes of stent failure include underestimation of the prostatic urethral length by the Surveyor leading to obstruction by apical prostatic tissue, excessive suture length between the stent and distal anchor permitting proximal migration or inadequate suture length leading to urinary incontinence. Further design modifications are suggested.

Epithelializing Stent for Benign Prostatic Hyperplasia: A Systematic Review of the Literature

PURPOSE

We systematically reviewed the literature on the effectiveness, durability and safety of the UroLume stent for men with benign prostatic hyperplasia.

MATERIALS AND METHODS

We searched the MEDLINE and EMBASE databases for 1989 to 2005. Reference lists of included studies and review articles were also searched. We contacted the UroLume manufacturer and key authors for additional information. Primary outcomes were treatment failure and urological symptom scores. Secondary outcomes were uroflow parameters and minor complications. Two reviewers independently assessed the methodological quality of the studies and extracted data.

RESULTS

A total of 20 case series evaluated the UroLume stent in a total of 990 patients with benign prostatic hyperplasia. Of the patients 84% who were catheter dependent voided spontaneously after stent insertion. Ten studies assessed symptoms before stent insertion and at some point within 1 year after stent insertion. All reported decreases in symptom scores, including Madsen-Iversen by 7.9 to 14.3 points and International Prostate Symptom Score by 10 to 12.4 points. Peak urine flow rates increased by 4.2 to 13.1 ml per second. A total of 104 stents (16%) failed in 606 patients who were evaluable at 1 year and migration was the commonest cause of failure (38 stents or 37%). Most patients initially experienced perineal pain or irritative voiding symptoms following stent placement.

CONCLUSIONS

Of men who were catheter dependent 84% voided spontaneously after insertion of a UroLume stent and the improvement in symptoms was similar to that seen after transurethral prostate resection. However, 1 of 6 men needed the UroLume removed within a year because of complications. Inadequate followup prevented conclusions on stent durability beyond 1 year. This review supports the recommendation that stents should be considered only in patients at high risk.

Evaluation of the Effects of Temporary Covered Nitinol Stent Placement in the Prostatic Urethra: Short-Term Study in the Canine Model

PURPOSE

To evaluate the effect of temporary stent placement on the canine prostatic urethra.

METHODS

Retrievable PTFE-covered nitinol stents were placed in the prostatic urethras of 8 beagle dogs under fluoroscopic guidance. Retrograde urethrography was obtained before and after stenting. Retrograde urethrography and endoscopy were performed 1 and 2 months after deployment. The endoscopic degree of hyperplasia was rated on a scale of 0 to 4 (0 = absence, 4 = occlusion). On day 60, stents were removed and urethrography was performed immediately before euthanasia. Pathologic analysis was performed to determine the degree of glandular atrophy, periurethral fibrosis, and urethral dilation.

RESULTS

Stent deployment was technically successful in 7 animals, and failed in 1 dog due to a narrow urethral lumen. Complete migration was seen in 2 animals at 1 month, and an additional stent was deployed. On day 30, endoscopy showed slight hyperplasia (grade 1) in 3 animals. On day 60, moderate hyperplasia (grade 2) was evidenced in 4 cases. No impairment of urinary flow was seen during follow-up. Retrieval was technically easy to perform, and was successful in all dogs. The major histologic findings were chronic inflammatory cell infiltrates; prostate glandular atrophy, with a mean value of 1.86 (SD 0.90); periurethral fibrosis, with a mean ratio of 29.37 (SD 10.41); and dilatation of the prostatic urethra, with a mean ratio of 6.75 (SD 3.22).

CONCLUSION

Temporary prostatic stent placement in dogs is safe and feasible, causing marked enlargement of the prostatic urethral lumen. Retrievable covered stents may therefore be an option for bladder outlet obstruction management in men.

Hourglass-shaped nitinol prostatic stent in treatment of patients with lower urinary tract symptoms due to bladder outlet obstruction

OBJECTIVES

To assess the efficacy and safety of the thermoexpandable hourglass-shaped nitinol prostatic stent in the treatment of patients with lower urinary tract symptoms due to bladder outlet obstruction.

METHODS

The stents were inserted in an outpatient setting under local anesthesia and direct vision. Five different stent lengths (2.0 to 4.0 cm) were used, depending on the length of the prostatic urethra. Assessment of voiding function and symptom scores was performed at baseline, directly after stent insertion, at 14 days, and 1, 3, 6, and 12 months after stent placement.

RESULTS

We enrolled 35 men in the trial. In 5 patients, insertion of the stent failed, mainly because of anatomical limitations. After all placement procedures, minimal temporary hematuria was observed. Spontaneous voiding was achieved in all patients, with immediate significant improvements in voiding parameters and symptom scores. The median indwelling time of the stent was 70 days. Kaplan-Meier survival analysis showed that at 14 days and at 3, 6, and 12 months, the stent was still in situ in 73%, 40%, 33%, and 23% of the patients, respectively. The main reason for removal of the stent was migration (93%), in most cases toward the bladder. Removal was uneventful in all but 1 case.

CONCLUSIONS

The placement of the thermoexpandable hourglass-shaped nitinol stent results in relief of outflow obstruction and improvement of symptom scores. Because of the high migration rate, however, this stent design needs further improvement to be suitable for clinical practice.

Ease of removal of thermo-expandable prostate stents

OBJECTIVE

To report the ease of removal of the Memokath 028 prostatic stent (Engineers & Doctors A/S, Hornbaek, Denmark), an important attribute of the 'ideal' prostatic stent.

PATIENTS AND METHODS

Data on patients who had had a Memokath 028 stent removed in three different centres in Europe over an 8-year period were collected retrospectively. Standardized forms were used to record relevant information from each physician's patient files.

RESULTS

Ninety-three patients had their stents removed at the three reporting centres; the mean indwelling time of their stent was 12.9 months, and most stents were inserted for symptomatic benign prostate disease. Reasons for removal included recurrent outlet or storage-type urinary symptoms, migration of the stent, stent-related pain, recurrent urosepsis and detrusor failure. The stents were removed on a day-case basis in 32% of patients. Topical anaesthesia or no anaesthesia was used in 48%. Of these patients, only 9% described moderate discomfort or worse. The procedure took a mean of 11 min and was felt to be easy or fairly easy in 90% of patients.

CONCLUSIONS

These data show the ease of removal of the Memokath 028 stent, reinforce its overall success in achieving the requirements of the ideal intraprostatic stent, and further emphasize the advantages of this implant over the epithelializing, permanent intraprostatic stent.

The 12-year outcome analysis of an endourethral wallstent for treating benign prostatic hyperplasia

OBJECTIVE

To evaluate the long-term results of using the Urolume(TM) endourethral prosthesis (American Medical Systems, Minnetonka, MN, USA) for managing benign prostatic hyperplasia (BPH), an alternative minimally invasive option.

PATIENTS AND METHODS

Sixty-two patients with moderate/severe lower urinary tract symptoms secondary to BPH were treated with the Urolume stent by one surgeon (J.H.P.). They were followed up at 12 weeks, 6 months and then yearly. Data recorded before and after treatment included symptom scoring, peak urinary flow rate (PFR) and postvoid residual volume (PVR). A one-way anova was used to compare baseline and the 5- and 12-year follow-up data.

RESULT

Twenty-two and 11 patients completed the 5- and 12-year follow-up, respectively. Twenty-one (34%) patients died with the stent in situ from causes unrelated to BPH and Urolume insertion. Twenty-nine (47%) stents were removed; 18 in the first 2 years, seven at 3-5 years and four at 9-10 years. Early stent explantation was primarily a result of poor case selection, or stent malposition/migration. Four stents were removed because the patient was dissatisfied. Late stent explantation was for symptom progression. At 5 years, the symptom score and PFR were 6.82 an 11.7 mL/s, respectively, compared with 20.4 and 9 mL/s at basleine (P < 0.05); at 12 years, the symptom score, PFR and PVR were 10.82, 11.5 mL/s and 80 mL, respectively. The mean quality of life score was 2 and no patient opted for any further treatment.

CONCLUSION

The Urolume wallstent is a safe treatment for BPH, in selected patients. Careful case selection and experience is mandatory. This stent can provide the urologist with an alternative along with other minimally invasive treatments for men with BPH at high risk of requiring transurethral resection.

Percutaneous Placement of Permanent Metal Stents for Treatment of Ureteroenteric Anastomotic Strictures

PURPOSE

To evaluate the efficacy of permanent metal stent placement in the treatment of ureteroenteric anastomotic strictures following failed balloon dilation or laser endoureterotomy.

PATIENTS AND METHODS

Metal stents were placed in six ureteroenteric anastomotic strictures in four patients presenting with recurrent obstruction after balloon dilation or laser endoureteromy. Patients were evaluated at 1 week postoperatively with antegrade ureterography and at 3 to 6 months with renal ultrasound or CT scans. Serum creatinine assays and physical examination were performed at serial postoperative clinic visits.

RESULTS

At 1-week follow-up, antegrade studies demonstrated a patent anastomosis in all six strictures. With a mean follow-up of 10 months (range 7-12 months), no stricture recurrence has been seen. All patients have been clinically stable, without episodes of pyelonephritis, flank pain, or need for indwelling stents or nephrostomy tube placement. Serum creatinine concentrations have been stable in all patients.

CONCLUSIONS

Metal stents offer a useful treatment option in patients who develop ureteroenteric anastomotic strictures after urinary diversion. Further, such stents may be used in patients failing balloon dilation or laser endoureterotomy. Further study to assess the long-term durability of metal stent placement is needed.

A novel temporary prostatic stent for the relief of prostatic urethral obstruction

OBJECTIVES

To determine the effect of a novel temporary prostatic stent (The Spanner, AbbeyMoor Medical, Inc., Minnesota, USA) on variables of voiding function and quality of life among patients with prostatic urethral obstruction.

PATIENTS AND METHODS

The stent design is very similar to the proximal 4-6 cm of a Foley catheter; this includes a proximal balloon to prevent distal displacement, a urine port situated cephalad to the balloon, and a reinforced stent of various lengths to span most of the prostatic urethra. There is also a distal anchor mechanism attached by sutures, and a retrieval suture which extends to the meatus and deflates the proximal balloon when pulled. The stent was inserted under topical anaesthesia in 30 patients. The maximum flow rate (Qmax), voided volume (W), postvoid residual (PVR), the International Prostate Symptom Score (IPSS) and stent position were assessed.

RESULTS

Stents remained in situ for a mean (range) of 57 (1-98) days. The mean overall Qmax at baseline and after insertion were 8.2 and 11.6 mL/s, representing a 42% improvement (P < 0.001); the respective mean overall Ws were similar, at 219.7 and 221.6 mL (0.9% increase, not significant) and the PVRs were 312.1 and 112.3 mL, representing a 64% decrease (P = 0.004). The overall mean IPSS declined from 22.3 before to 7.1 after insertion, representing a 68% decrease (P < 0.001). There were only minor adverse events. The stability, patency and lack of migration of the device were confirmed radiographically up to 12 weeks of use.

CONCLUSIONS

This early study shows that this temporary prostatic stent is easily inserted and removed, remains anchored in position, and significantly improves the Qmax, PVR and IPSS while preserving volitional voiding and continence.

Experience with urethral stent explantation

PURPOSE

We examined the timing, causes and results of the explantation of UroLume (American Medical Systems, Minnetonka, Minnesota) urethral stents.

MATERIALS AND METHODS

The North American Study Group enrolled 465 patients in a trial of UroLume stent placement, including 69 (14.8% of the series) who required removal of a total of 73 stents (15.6% of stents) in 7 years. The time of explantation, reason for stent removal and local histological findings were determined from patient charts and reviewed in relation to the indication for stent placement.

RESULTS

In patients treated for bladder outlet obstruction secondary to benign prostatic hyperplasia 23% of the stents were removed, as were 5% of those implanted in patients with bulbar urethral stricture and 22% of those in patients with detrusor-sphincter dyssynergia (see figure). Of the explantations 43.8% were done during year 1. Migration and/or inappropriate placement was the cause in 38.4% of cases. The most common stent site tissue finding was focal inflammation with a hyperplastic tissue response. Stent specific malignant changes were not observed. Stent removal was feasible with no sequelae. CONCLUSIONS When used appropriately, the UroLume endoprosthesis has a low incidence of failure. Stent removal is technically feasible and options are available for subsequent therapy. Local tissue reaction is minimal.

Thermo-expandable intraprostatic stents in bladder outlet obstruction: an 8-year study

OBJECTIVE

To assess the use of a thermo-expandable intraprostatic stent (Memokath(R), Engineers and Doctors A/S, Copenhagen, Denmark) for bladder outlet obstruction in men unable to undergo transurethral resection of the prostate (TURP), assessing symptoms, complications and duration of stent life.

PATIENTS AND METHODS

The Memokath stent is a coil of a nickel-titanium alloy which has 'shape memory', the lower end expanding when heated to 55 degrees C. Risks associated with inserting the stent with a flexible cystoscope under local anaesthesia are minimal. Men were selected who were either permanently or temporarily unfit for TURP. Indications included severe respiratory and cardiovascular disease. Exclusion criteria included bladder carcinoma, calculi or detrusor failure; in all, 211 men were fitted with 217 intraprostatic stents over 8 years.

RESULTS

There were 1511 TURPs during the study period; the mean age of men receiving a stent was 80.2 years, compared with 70.2 years for those undergoing TURP. The International Prostate Symptom Score decreased from a mean of 20.3 to 8.2 (P < 0.001) in the first 3 months after stent placement; there was virtually no change over 7 years. During the follow-up, 38% of men died with their stents in situ, 34% remain alive, 23% have had their stents removed for failure and 4% were removed as they were no longer required. There was a 13% migration rate and 16% repositioning rate. There were few side-effects (pain 3%, haematuria 3%, incontinence 6% and infection 6%). These frail men were more likely to die than have their stent fail.

CONCLUSION

The Memokath intraprostatic stent is a valuable addition to the armamentarium of the urologist treating elderly or frail men with advanced bladder outlet obstruction and complements existing technologies.

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.