The use of prostatic stents in patients with urinary retention who are unfit for surgery. An interim report

Temporary placement of covered retrievable expandable nitinol stents with barbs in high-risk surgical patients with benign prostatic hyperplasia: work in progress

PURPOSE

To report the use of a newly constructed, covered, retrievable, expandable nitinol stent with barbs to overcome the problem of stent migration associated with conventional covered prostatic expandable stents and to evaluate prospectively the technical feasibility and clinical effectiveness of the stents in patients with benign prostatic hyperplasia (BPH).

MATERIALS AND METHODS

A covered retrievable expandable nitinol stent with four barbs was placed with use of an 18-F stent delivery system in seven consecutive patients with symptomatic BPH who had high operative risks. Age range of patients was 62-83 years (mean 74 years). In cases in which the stent migrated, it was replaced with a stent with eight barbs. The stents were routinely removed 4 months after placement using a 21-F stent removal set.

RESULTS

Stent placement was technically successful and well tolerated in six of the seven patients. The remaining patient needed a second stent placement after removal of the first stent. The stent with four barbs migrated into the urinary bladder in four patients (57%); three of these patients received a second stent with eight barbs with good results, and the fourth patient did not need further treatment because his symptoms improved. Routine removal of the stent 4 months after placement was performed in three of the seven patients with good results.

CONCLUSIONS

Retrievable stents with eight barbs seem to overcome the problem of stent migration associated with conventional prostatic expandable stents. Preliminary results suggest that stents with barbs are both feasible and effective in patients with BPH.

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.

Interventional radiology and the use of metal stents in nonvascular clinical practice: a systematic overview

PURPOSE

The intent of this systematic overview was to describe the clinical role of metal stents in nonvascular health care interventions and the level of evidence supporting their use.

MATERIALS AND METHODS

Structured searches of Medline were conducted and limited to original peer-reviewed articles published in English.

RESULTS

Clinical practice involving metal stents was reported in more than 109 clinical series involving 4,753 patients. Stents were placed mainly for palliation of malignant biliary, esophageal, and airway obstruction in patients who were untreatable or had surgically unresectable lesions. Assessment of these interventions has so far centered on safety and technical success. Efficacy, quality of life, and costing factors were not routinely reported. Randomized trial evidence was available but limited; six randomized trials involving metal stents have been reported. Three trials involved biliary malignant obstruction, and all three reported metal stent (132 patients) palliation to be superior to plastic stent palliation (136 patients) based on longer patency and lower reintervention costs. Safety and complication differences between stents, however, were inconsistent across trials. In three trials involving esophageal malignant obstruction, metal stent (82 patients) palliation was reported to be superior to plastic stent (41 patients), based on lower complication and reintervention rates, and superior to laser therapy (18 patients), based on better dysphagia relief.

CONCLUSION

Use of metal stents has been reported for obstructed ducts and passageways of most body systems. There is, however, limited controlled trial evidence confirming the advantages of their use over plastic stents or other forms of treatment.

How to select patients suitable for transurethral microwave thermotherapy: a systematic evaluation of potentially predictive variables

OBJECTIVE

To identify clinical variables useful in predicting outcome after transurethral microwave thermotherapy (TUMT) of the prostate with Prostasoft v. 2.0.

PATIENTS AND METHODS

Thirty-eight men with symptomatic benign prostatic hyperplasia (BPH) were treated with TUMT using the Prostatron device with the low-energy (v. 2.0) software. Before and 6 months after treatment symptoms were evaluated using the Madsen-Iversen (M-I) symptom score, a clinical examination and suprapubic pressure-flow measurement, free urinary peak flow rate (Qmax) and determination of post-void residual urine volume (PVR). Bladder outlet obstruction was assessed from urodynamic pressure-flow studies using the classification of Abrams and Griffiths, the obstruction grading of Schäfer, and calculation of other published factors, e.g. the urethral resistance, an obstruction index and the detrusor adjusted mean passive urethral resistance factor (DAMPF). Categories of M-I score (total, irritative and obstructive), PVR and Qmax were investigated to determine whether any could predict the outcome after low-energy TUMT. The values after treatment and changes in Qmax, M-I score and PVR were used as efficacy variables.

RESULTS

Variables describing infravesical obstruction had predictive characteristics that may be useful in selecting patients for TUMT v. 2.0 and significantly better results were obtained in patients with a low to moderate obstruction as graded using the DAMPF classification of obstruction. The results also indicated that patients with a high irritative M-I score or a Qmax of 7-14 mL/s were those who fared best after TUMT.

CONCLUSIONS

Variables expressing the obstruction grade seem to be useful in predicting outcome after TUMT (v. 2.0). Patients with a high obstruction index are probably unsuitable for TUMT (v. 2.0).

Does anamnestic symptom evaluation or clinical examination give enough information to evaluate the severity of obstruction in benign prostatic hyperplasia?

In this study we have investigated 70 men fulfilling the usual criteria accepted for transurethral resection of the prostate (TURP). The anamnestic evaluation included the Madsen-Iversen symptom score and a quality of life questionnaire. The clinical examination included suprapubic pressure flow measurement, free urinary flow, the determination of residual urine and the ultrasound evaluation of the size of the prostate. The clinical data were correlated with the grade of obstruction according to Schäfer calculated from the pressure/flow studies. No correlation was found between the grade of obstruction and anamnestic symptom data, the size of the prostate or residual urine. A slight correlation was found between the Schäfer grade of obstruction and the flow curve pattern or peak flow.

Heat-expansible permanent intraurethral stents for benign prostatic hyperplasia and urethral strictures

We report our experience with the insertion of a new thermoexpansible permanent intraurethral stent, the Memotherm. We treated 49 patients, 25 with benign prostic hyperplasia (BPH), 21 with recurrent urethral strictures (2 cervicourethral and 18 bulbar and 1 of a vescicourethral anastomosis after radical prostatectomy), and 3 with sphincterotomies (2 for dyssynergia and 1 with incontinence plus stenosis). The patients' ages ranged from 24 to 84 (mean 59.7) years. In all patients, stent insertion was achieved without any operative problem. In two patients, stents were removed (one in the BPH group and one in the urethral stricture group), and at long-term follow-up, we have seen two patients with severe mucosal hyperplasia.

The North American experience with the UroLume endoprosthesis as a treatment for benign prostatic hyperplasia: long-term results. The North American UroLume Study Group

OBJECTIVES

To determine the efficacy and safety of the UroLume endoprosthesis as a treatment for obstructive benign prostatic hyperplasia in healthy men.

METHODS

One hundred twenty-six men were enrolled prospectively in a multicenter North American Clinical Trial. Ninety-five men (mean age 68 +/- 7 years) had moderate or severe prostatism, whereas 31 participants (mean age 76 +/- 8 years) were in urinary retention. Voiding function for all patients was assessed prior to stent placement and in follow-up at 1, 3, 6, 12, and 24 months with the Madsen-Iversen symptom questionnaire, peak urinary flow rate, postvoid residual urine volume, and cystoscopic examination.

RESULTS

For the nonretention cohort at 24-month follow-up, the results were as follows: (1) total symptom score decreased from 14.3 +/- 0.5 preinsertion to 5.4 +/- 0.5 (p < 0.001); (2) peak urinary flow rate increased from 9.1 +/- 0.5 mL/s preinsertion to 13.1 +/- 0.7 mL/s (p < 0.001); and (3) postvoid residual urine volume decreased from 85 +/- 9 mL to 47 +/- 8 mL (p = 0.02). For the retention group, the total symptom score, peak urinary flow rate, and postvoid residual urine volume at 24 months were 4.1 +/- 0.5, 11.4 +/- 1.0 mL/s and 46 +/- 7 mL, respectively. By 12-month follow-up, most endoprostheses were completely covered with urothelium. Although significant long-term complications were minimal, 17 endoprostheses have been explanted for an overall removal rate of 13%. All devices were removed transurethrally without subsequent sequelae to the external urinary sphincter or urethra.

CONCLUSIONS

The long-term results from this North American Clinical Trial suggest that the UroLume endoprosthesis can be an effective and safe treatment for properly selected healthy men with obstructive benign prostatic hyperplasia. Randomized clinical trials comparing this minimally invasive procedure with transurethral resection of the prostate are now underway to document further its efficacy and safety.

Transurethral microwave thermotherapy (TUMT) in benign prostatic hyperplasia: placebo versus TUMT

OBJECTIVES

A prospective, randomized placebo-controlled study was designed to exclude a placebo response in transurethral microwave thermotherapy (TUMT).

METHODS

During a sham procedure, the microwave applicator was installed in the urethra as in the real TUMT treatment and a complete procedure was simulated by the microwave delivery system (Prostatron). Any patient who entered this study had the option to request a second real TUMT treatment if, 3 months after the initial procedure, his condition had not improved.

RESULTS

A total of 48 patients were available for evaluation at 3 months and 28 at 6 months. The TUMT group had an average decrease of 7.3 points (from 13.2 to 5.9) in the Madsen symptom score, an average increase in flowrate of 3.4 mL/s (9.6 to 13.0), and an increase in voiding percentage of 9.6% (81.7 to 91.3). All improvements were statistically significant. In the sham group, the average Madsen score decreased from 12.1 to 8.2 points, the average flowrate decreased from 9.7 to 9.5 mL/s, and the voiding percentage increased from 80.8% to 84.3%. Only the change in symptom score was significant. In both groups, observations at the 3-month follow-up were similar to those after 6 and 12 months. Patients who had TUMT after sham treatment showed similar significant changes in symptom score and peak flow as observed in the original TUMT group. Patients who did not respond favorably to a first TUMT did not experience improvement after a second TUMT.

CONCLUSIONS

A placebo effect, although minimal, exists. This placebo response, however, accounts for little of the observed benefit of TUMT.

Stent of shape-memory alloy for urethral obstruction caused by benign prostatic hyperplasia

Dilation and positioning a stent in the prostatic urethra have become important alternatives for the management of benign prostatic hyperplasia (BPH), but both have significant drawbacks, namely the need to repeat the treatment in the former case and the conflict between the introducing means and the generation of sufficient expansile force in the latter case. A spiral of a Chinese titanium-nickel alloy with shape memory was implanted in 25 patients with BPH using a self-made coaxial sheath. With a follow-up of 3 to 20 months, the success rate is 92%. There has been no encrustation or migration of the spirals. We deem the spiral of this shape-memory alloy to be a good alternative in patients with BPH who are unfit for surgery.

Use of multiple Wallstents in treatment of bladder outlet obstruction

Of 23 patients being treated with the Urolume Wallstent for bladder outlet obstruction, 4--3 with anterior urethral strictures and 1 with benign prostatic hyperplasia--required two to four stents. When placing multiple stents, there should be enough overlap to prevent the opening of a gap as the stents expand and shorten over the ensuing weeks. Use of more than 1 stent is indicated when the stricture or the prostatic urethra is longer than 3 cm or when stricture recurs beyond the end of a previously placed stent.

Endoluminal urethral stents: a review

Although Fabian first introduced the concept of an endourethral stent in 1980, recent developments in biomedical technology and the treatment philosophy of urethral obstruction has led to a resurgence of this concept. We review the past and current literature with regard to both temporary and permanent stents. Available stents are described, clinical results summarized, and indications discussed.

Urologic applications of a permanent, epithelializing urethral endoprosthesis

Recently, a flexible, self-expanding, permanent endoprosthesis has been developed to maintain patency of stenotic arteries after balloon angioplasty. This device, known as the UroLume Wallstent, is now under active investigation in both Europe and the United States as a treatment for: (1) recurrent bulbar urethral strictures, (2) benign prostatic hyperplasia, and (3) detrusor-external sphincter dyssynergia. Preliminary data demonstrate this device to be an effective treatment for all three indications in select patients and to be associated with minimal untoward effects. If the long-term results are equally encouraging, this unique endoprosthesis will represent a significant advancement for the field of urology.

The "Wallstent": a new stent for the treatment of urethral strictures

Ten patients have been reviewed in whom urethral stents were implanted for treatment of urethral stricture. Their urethral strictures had been treated with a median of 4.2 endoscopic urethrotomies under direct vision without success. The patients were first treated with optical urethrotomy, and dilatation to 30 F--after which the stents were inserted under direct endoscopic control. A total of 12 stents were inserted. All patients had a 30 mm stent inserted first, and two patients had an additional 20 mm stent inserted because of recurrent stricture at the distal or proximal end of the first stent. One patient had a urethrotomy 12 months after insertion of the stent because of a short recurrent stricture at its distal end. The median length of follow up was 24 months. The median preoperative maximum flow rate was 6.5 ml/s, and the median postoperative maximum flow rate was 20.3 ml/s. Half the patients had postmicturition dribbling postoperatively. The stents were covered with epithelium after 6-18 months, most between 12 and 18 months.

Restenosis of the urethra despite indwelling Wallstent

Of 5 patients with recurrent urethral strictures were treated with a self-expandable permanently implanted urethral stent 2 had stenosis within the stent 2.5 and 9 months after placement of the stent, respectively.

Nonsurgical, nonpharmacologic treatment of benign prostatic hyperplasia

New treatment modalities are becoming available for benign prostatic hyperplasia. Permanent or temporary stenting of the prostatic urethra, balloon dilatation of the prostate, and hyperthermia and thermotherapy are in the forefront. None of the methods has found a definite place in the spectrum of indications. Prospective trials are needed to ascertain the safety, efficacy, and durability of results.

Encrustation of intraprostatic stents--a comparative study

Metallic stents have been used in the management of prostatic disease in patients unfit for surgery. A variety of stents have become available but the optimum design and metal of construction has not yet been defined. This study examined one of the potential complications of stent insertion by demonstrating that they are susceptible to encrustation. Using an in vitro model it compares the ability of the different materials used in their construction to resist this encrustation. Titanium appears less able to resist deposition than the other metals examined. The long-term complication of encrustation may inhibit the use of some of these stents.

The Intraprostatic Spiral: Clinical Results In 150 Consecutive Patients

The clinical results of treatment of infravesical prostatic obstruction with an intraurethral coil in 150 consecutive patients are reported. A total of 80 patients had urinary retention and 70 had severe prostatism. Median observation time was 8.2 months, with a range of 0 to 40 months. In 75 patients the spiral was removed after a median of 4 months (range 0 to 30 months) because of planned prostatectomy in 17, urinary retention in 16, incontinence in 10, local discomfort in 7, no symptomatic improvement in 13 and causes not related to the spiral (stroke and so forth) in 7. Migration occurred 55 times in 42 patients but this only led to coil removal in 5. A total of 23 patients died with the coil in situ. Voiding symptoms improved considerably in the majority of the patients. Approximately two-thirds of the patients had no or few symptoms, while a fourth had moderate symptoms, leaving only approximately 10% with severe prostatism. Chronic bacteriuria was noted in 52 patients but was not a clinical problem. Calcification on the top and inside of the coil was noted mainly after long-term treatment, and probably necessitated exchange of the coil after 2 to 3 years. We conclude that the prostatic spiral is a useful alternative to an indwelling catheter. However, life-long followup is necessary in most patients.

Alternatives to prostatectomy

The danger of the treatments described are that patients may be treated without referral to a urologist. Investigations to determine whether genuine obstruction is the cause of their symptoms may not be performed and follow-up to exclude the side effects of their outflow obstruction or indeed their treatment may not be carried out. In addition, in cases where digital palpation does not alert the clinician to the possibility of prostatic malignancy, the loss of specimens for histological interpretation may lead to missed diagnoses. In summary, the alternatives to prostatectomy are still limited. Hormonal manipulation, hyperthermia and prostatic dilatation using the smaller balloons have no role at present in symptomatic patients. The role of larger balloons has still to be determined. Alpha blockade, while achieving relief in the short-term, still requires long-term objective follow-up studies in patients with urodynamically proven obstruction to assess patient compliance and the effects of treatment before it can be recommended as a long-term alternative. Similar information is also required before the efficacy of hyperthermia in patients with retention can be determined. For high risk patients with a limited life expectancy who present with retention of urine, prostatic stents may have a role, but once again long-term follow-up data are required before this treatment can be advocated in fitter or symptomatic patients.