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

Authors


Chryssanthos Kouriefs, 1 Galahad House, Knights Place, Noke Drive, Redhill, Surrey RH1 4AZ, UK.
e-mail: C.Kouriefs@btinternet.com

Abstract

OBJECTIVE

To evaluate the long-term results of using the UrolumeTM 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.

Abbreviations
PFR

peak flow rate

PVR

postvoid residual urine volume.

INTRODUCTION

BPH is the commonest urological condition in elderly men [1], and TURP remains the reference standard treatment for symptomatic BPH. The associated complication rate and need for regional/general anaesthetic resulted in an interest in minimally invasive and potentially safer treatments [2]. These include pharmacotherapy (α-blockers, 5α-reductase inhibitors), transurethral thermotherapy, transurethral electrovaporization of the prostate, high-intensity focused ultrasound, ‘laser’ techniques and urethral endoprostheses. Some of these have shown early promising results, but for some there is no evidence for satisfactory sustained long-term results. We previously published our 5-year follow-up of 62 patients with BPH treated with the UrolumeTM self-expanding endourethral prosthesis (American Medical Systems, Minnesota, USA) [3]. We herein report our 12-year follow-up data, which to our knowledge is the longest follow-up study reported on the use of the Urolume stent for treating BPH.

PATIENTS AND METHODS

Sixty-two men with BOO secondary to BPH were treated at our institution with the Urolume wallstent between 1991 and 1992. All patients had moderate to severe LUTS and were awaiting an elective TURP; none had a catheter in situ. The preoperative assessment included the IPSS, a physical examination including a DRE, urine culture, biochemical tests (urea, electrolytes and PSA) and a measurement of urinary peak flow rate (PFR), postvoid residual urine volume (PVR), and flexible cystoscopy. Patients with urethral stricture, a history of previous prostatic surgery, bladder or prostate carcinoma, bladder stones and neuropathic bladder were excluded from having a Urolume stent. All stents were inserted by the senior author (J.H.P.). Patients were followed at 2, 6 and 12 weeks, and 6 months and then yearly. The follow-up included the IPSS, PFR, PVR and flexible cystoscopy. Twenty-two men were followed for 5 and 11 for 12 years. A paired t-test, Mann-Whitney rank sum and one-way anova were used to compare the baseline, 5- and 12-year follow-up data.

RESULTS

The mean (range) age of the initial 62 men was 67 (40–89) years; their American Society of Anesthesiology score was I in 39%, II in 41%, III in 8% and IV in 2%, consistent with a relatively fit cohort of men. During the first 5 years of follow-up, 25 stents (40%) were removed, i.e. nine (36%) for malpositioning, eight (32%) as a result of poor case selection, four (16%) for device failure (migration) and another four (16%) because the patient was dissatisfied. Most of these 25 stents were removed during the first (48%) and second (24%) years of follow-up. Three stents were removed in the third year, two in the fourth and two in the fifth; no stent was removed at 5–9 years. Another four stents were then removed at 9 or 10 years because of progressive BOO and worsening symptoms. In all, 29 stents (47%) had been removed at 12 years (Fig. 1).

Figure 1.

The stents explanted (per year, red closed circles; cumulative, light red triangles), or remaining in situ (green open circles). Most stents were explanted in the first 2 years of follow-up; in all, 29 were removed at 12 years.

The complications are summarized in Table 1; there was early urinary retention in five (8%) men, managed with suprapubic catheterization in two (3%) and bladder washout (clot retention) in the rest (5%). Five men had a UTI (8%), managed with antibiotics. There was self-limiting urge incontinence in 12 (19%) men. The commonest early adverse event was dysuria, in half the men, but this resolved in all within 3 months. Late complications included a urethral stricture in one man (1.6%) and recurrent delayed haematuria in four (6.5%).

Table 1.  The early and late complications associated with Urolume stent insertion for BPH
ComplicationsNManagement
Immediate
Urinary retention2Suprapubic catheter
Clot retention3Bladder washout
Early
UTI4Antibiotics
Epididymitis1Antibiotics
Urge incontinence12Expectant (no treatment)
Haematuria4Expectant (no treatment)
Dysuria31Expectant (no treatment)
Late (up to 5 years)
Calcification2Expectant (no treatment)
Stricture1Urethral dilatation
Haematuria1Investigations
Intractable urgency, persistent BOO symptoms, stent migration, prostate too large, poor positioning25Removal of Urolume
Late (5–12 years)
Haematuria3Investigation
Progressive BOO symptoms4Remove Urolume, TURP

Twenty-one (34%) patients died during the follow-up with the stent in place, all from causes unrelated to BPH. One patient was diagnosed with an invasive bladder carcinoma and had a cystoprostatectomy.

Eleven men (18%) completed the 12 years of follow-up with the stent in situ (mean age 79 years, range 72–84). The mean IPSS and quality-of-life scores were 10.8 and 2.4, respectively, compared with 6.7 (P < 0.05) and 1.3 (P = 0.012) at 5 years. The mean PFR and PVR were 12.1 mL/s and 87 mL, respectively. There was no statistically significant difference in PFR between 5 and 12 years (P = 0.6). On flexible cystoscopy, eight of the 11 the stents were completely re-epithelialized, whereas three were partly (<10%) exposed, with minimal encrustation. Four men had mild-to-moderate and two marked epithelial hyperplasia with no significant anatomical obstruction.

DISCUSSION

Alexis Carrel is credited with the novel idea of using stents for obstructed luminal viscae, publishing his experience in stenting canine thoracic aortae with glass and metal tubes covered with paraffin wax, in 1912 [4]. Charles Dotter, a vascular surgeon, reintroduced the concept of using implantable prosthetic devices to maintain luminal integrity of diseased vessels in 1964. Fabian [5] first described the use of a ‘urological spiral’, a temporary stent, in treating BOO, in 1980. Since then, the idea of permanent (epithelializing) and more recently biodegradable stents has been introduced. The Urolume is a permanent stent made of a single stainless-steel superalloy wire woven in a tubular mesh. Its shape allows the urothelium to grow through the interstices and completely epithelialize the stent, maintaining the urethral lumen at 42 Fr. Such a calibre allows the introduction of a resectoscope sheath through the stent for future interventions. Its deployment is easy, safe and can be done under local anaesthesia. The Urolume has been used for BPH, bulbar urethral strictures and detrusor sphincter dyssynergia [6].

BPH is the commonest urological condition; half of men aged 51–60 and 90% aged > 90 years have histological evidence of BPH [7]. About 40% of men will need surgical treatment for BOO secondary to BPH at an average age of 74 years [8]. TURP has dominated the surgical treatment of BPH and is the reference treatment, with a sustained symptom improvement of 75–90%[2]. However, 10–15% of elderly men with symptomatic BPH are considered unfit for TURP. Furthermore, the morbidity and mortality rates after TURP are 25% and 0.2%, respectively, or even higher (30% morbidity) in men aged > 80 years [9]. These disadvantages make TURP an unsuitable treatment option for the very elderly and frail. Such patients would benefit from minimally invasive treatments such as prostatic stents. Prostatic stents, like other minimally invasive treatments for BPH, have been questioned because there are few long-term follow-up data. The present study, unique in having a follow-up of > 10 years, should provide clinicians with information and evidence on the durability of prostatic stents, and will help patient counselling and deciding about treatment.

Early symptomatic improvement after prostatic stenting has been reported by three prospective unrandomized studies from North America and Europe (Table 2) [10–12]. In the North American Urolume multicentre trial [10], 126 healthy men with symptomatic BOO were treated with the Urolume prostatic stent. At 12 months, the symptom score and mean PFR improved significantly (P < 0.001). In a European multicentre study, Guazonni et al.[12] reported on 135 men with BOO treated with the Urolume stent. The PFR and symptom score also improved significantly at 1 year. The important point is whether the improvement in symptoms is sustainable. Previously we reported intermediate (5-year) follow-up results, which showed a significant improvement in PFR and IPSS [3]; at 5–12 years there was a slight decline in the mean PFR but it was not statistically significant (P = 0.6). The IPSS and quality-of-life scores were significantly greater at 5–12 years (P < 0.05 and 0.012). However, at the 12-year follow-up the men were even older (mean 79 years) and some symptomatic decline would be expected. What is most important is that all of the 11 patients who completed the 12-year of follow-up were offered alternative treatments but all reported being satisfied with their symptoms and declined any further treatment.

Table 2.  The 2-year results of the three main trials of the use of the Urolume for BPH
Variable[12][10][11]
  1. n/a- not available.

N13512696
Before stenting
Symptom score 14.114.017.9
PFR, mL/s 9.3 9.1 8.0
Follow-up, months:
12
Symptom score 6.4 5.9 3.4
PFR, mL/s 15.7 13.018.1
24
Symptom scoren/a 5.4 3.5
PFR, mL/sn/a 13.111.1

Another criticism of prostatic stents is the high explantation rate. Guazzoni et al.[12] reported an overall 29% explantation rate at the 18-month follow-up. Similarly, the explantation rate at the North American trial was 23% at 7 years [10]. Williams et al.[11] reported a lower explantation rate of 11%. In the North American trial half the explantations were in the first year of follow-up, for stent migration or displacement. The explantation rate reported by groups using stents for treating detrusor-sphincter dyssynergia was similar to that reported in BPH series, but the rate reported by groups using stents for bulbar urethral strictures was significantly lower, at 5%[6]. In the present series (Fig. 1), the explantation rate at 12 years was high (47%). This can be explained by the lack of strict exclusion criteria, relative inexperience, but most importantly by the significantly longer follow-up. At 2 years the explantation rate was <30%, which is comparable with other published data; 41% of the explanted stents were removed in the first and another 21% in the second year. Only four stents were removed at 5–12 years, because of symptom progression. Amongst the 25 stents explanted over the first 5 years, a third were removed because of malpositioning. This can be improved with experience and indeed permanent stent placement requires considerable training. Four stents (16%) were removed because of migration, which again may be related to technique or anatomical and physiological factors. Most importantly, eight (32%) of these stents were removed because of poor case selection; this is preventable, and case selection is very important. Urolume stenting should be avoided in men with a high bladder neck, short (<2 cm) or very long prostates (>4.5 cm). The presence of prominent irritative symptoms should be considered a relative contraindication to Urolume insertion, as such symptoms deteriorate afterward. As noted, other contraindications include neuropathic bladder, bladder stones, bladder or prostate cancer and previous prostatic surgery. Only four of the stents were removed because the results were unsatisfactory despite adequate positioning.

During the 12 years of follow-up, 21 patients (34%) died from unrelated causes, with the stent in place. The present patients had direct access to primary-care groups and our department. None of the 21 patients contacted their GP or us about any voiding dysfunction, and thus we can only assume that they were satisfied with their stent. The men were relatively healthy but had BPH; the 12-year mortality rate in a cohort of older and less fit men would be expected to be more than 34%. In such a selected cohort of older and unfit patients, a higher proportion would die with the stent rather than outlive its ‘lifespan’. If we define successful treatment to be satisfactory symptomatic improvement with no need for further intervention, then patients dying from other causes with the stent in situ should be considered as a success. However, there is a hypothetical risk of the need for a higher explantation rate in older and less fit men whose initial symptoms are more likely to be more severe and may be more irritative. Such a need for explantation would subject patients to a second procedure of removing the stent. In our experience the procedure is easy and can be done under general or local anaesthesia with sedation. The senior author has previously reported the technique for removing Urolume stents [13].

The present study has some weaknesses; it was not a randomized prospective study, had relatively few patients, and included men voiding spontaneously. The need for intervention was based on their symptoms and PFR. In an ideal situation the men should have been assessed before stenting by pressure-flow analysis to identify BOO, and afterward to predict success.

The Urolume for men with BPH is a useful tool and an alternative to other minimally invasive procedures. We do not propose that the Urolume is used as a first-line treatment, and we do not consider it to be as effective as TURP, but it can be useful in carefully selected patients. In our institution we now reserve the Urolume for treating BPH and retention in men who are unfit for general anaesthetic, do not respond to medical treatment and do not wish to have a long-term indwelling urethral catheter. Other minimally invasive surgical options should also be considered in such patients, e.g. thermotherapy, electrovaporization, focused ultrasound and ‘laser’ techniques.

CONFLICT OF INTEREST

None declared.

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