Pure Bipolar Plasma Vaporization of the Prostate: Results from a Prospective 3D Ultrasound Volumetry Study with Clinical Outcome After 3 Years

Abstract

Introduction and Objectives:

Bipolar plasma vaporization (BPV) has been shown to be a low-morbidity alternative to conventional transurethral resection of the prostate (TURP). Improved functional short-term outcome and a postoperative prostate volume reduction comparable to TURP have been reported. However, comprehensive mid- or long-term results following BPV are still lacking.

Methods:

A consecutive series of men who underwent pure BPV in a tertiary care academic center was prospectively investigated. Clinical parameters [International Prostate Symptom Score with Quality-of-Life domain, peak urinary flow rate (Qmax), postvoid residual volume, and prostate-specific antigen] as well as prostate volume (assessed by planimetric volumetry following transrectal 3D-ultrasound) were recorded preoperatively and regularly after BPV (after catheter removal, 6 weeks, 6 months, 1 year, and 3 years). Statistical analysis was performed using the Wilcoxon signed-rank test. All p-values ≤0.05 were considered significant.

Results:

Seventy-five men were included in this prospective investigation. Their median (interquartile range) prostate volume was 41.0 mL (30.6–57.4 mL). In the first year after BPV, the prostate volume continuously decreased over time and the relative volume reduction was 52.2% after 12 months. Subsequently, the volume reduction remained stable with 50.7% after 3 years. All investigated outcome parameters improved significantly after the procedure and remained so after 3 years. Reoperations due to persistent or regrown adenoma were not necessary. Six (8.0%) and five patients (6.6%) developed a de novo urethral stricture or bladder neck contracture, respectively.

Conclusions:

Three years after pure BPV of the prostate, a durable prostate volume reduction in combination with a stable improvement of functional outcome parameters was detectable in our prospective study. The low morbidity of the procedure and the possibility to perform BPV under ongoing platelet aggregation inhibition confirms its role as minimally invasive alternative to conventional TURP.

Introduction

Conventional transurethral resection of the prostate (TURP) is still the standard surgical treatment for men suffering from lower urinary tracts symptoms due to enlarged prostates of 30–80 mL in size.¹ TURP offers excellent functional long-term results.^2,3 Overall, retreatment rates of 6% to 14% after up to 10 years have been reported.^4,5 Demographic changes required an extension of the indication for deobstructive prostate surgery to older patients with more comorbidities and to patients with platelet aggregation inhibitors (PAI) or on anticoagulation therapy.⁶ Thus, alternative surgical options with comparable performance but lower morbidity (i.e., less bleeding, although better coagulation properties reduced absorption of hypotonic irrigation fluid) were developed.

Bipolar plasma vaporization (BPV) of the prostate combines the advantages of a bipolar electrosurgery (improved coagulation and irrigation with isotonic saline) of the prostate with those of tissue vaporization (better coagulation with good intraoperative visibility).⁷ These properties make BPV a low morbidity alternative to conventional TURP. Low intra- and perioperative morbidity as well as excellent functional short-term results have been shown in several BPV studies.^8

–11 In a randomized trial, Geavlete and colleagues have shown that the outcome of 18 months after BPV was even superior to monopolar and bipolar TURP.¹² However, comprehensive mid- or long-term outcome following pure BPV is still lacking.

The extent of tissue ablation is a factor that affects the functional outcome and particularly the durability of a deobstructive procedure.¹³ In patients undergoing TURP, the amount of resected tissue can be estimated by weighing the removed prostate chips. Transrectal 3D ultrasound in combination with planimetric volumetry of the prostate allows to reliably determining tissue removal after prostate vaporization.¹⁴ We have previously shown that prostate volume reduction was comparable following BPV and TURP after a follow-up of 12 months.⁷ The aim of the present study was to investigate whether tissue reduction and functional outcome remain stable after three years.

Patients and Methods

This prospective investigation included a consecutive series of men who underwent pure BPV in our tertiary care academic center. The local Ethics Committee approved the study protocol and written informed consent was obtained from all included patients. The study design encompassing patient selection, inclusion criteria, exclusion criteria, and perioperative management was previously described in detail.⁷ Generally, BPV was performed in patients with prostate volumes between 30 and 80 mL in size. In patients under PAI, the medication was not stopped before surgery. Patients under oral anticoagulation (e.g., coumarine derivates) were excluded from the current study. Preoperatively, the following parameters were assessed: the International Prostate Symptom Score (IPSS) with Quality-of-Life (QoL) domain, peak urinary flow rate (Qmax), postvoid residual volume (RV), and prostate-specific antigen (PSA) values. The regular preoperative workup also included a complete blood count, coagulation parameters, and a urinalysis. In addition, transrectal 3D ultrasound of the prostate was performed using a ProFocus 2202 Ultrasound Scanner in combination with a UA0513 Magnetic Wheel Probe mover (both BK Medical, Herlev, Denmark). Planimetric volumetry of all generated images was performed using BK3D software version 7.0.0.519 (BK Medical) in 2 mm sections in the sagittal plane to accurately measure the pre- and postoperative prostate volumes.

Surgery was performed by a total of five surgeons (three senior surgeons and two senior residents) using a SurgMaster UES-40 generator in combination with a 26F OES continuous-flow Iglesias resectoscope and the first-generation hemispherical vaporization electrode (all Olympus Winter & Ibe GmbH, Hamburg, Germany). Tissue vaporization was performed as described previously (power output settings: 290–320 W for vaporization, 150–170 W for coagulation).¹⁰ The postoperative management was also described earlier.⁸

Follow-up visits took place after 6 weeks, 6 months, 1 year, and 3 years. At each follow-up visit, transrectal 3D ultrasound of the prostate was performed. In addition, IPSS and QoL, Qmax, RV, and PSA values were assessed. Relevant long-term complications (i.e., urethral stricture and bladder neck contracture) and repeat procedures were recorded.

Statistical analysis was performed using IBM^® SPSS^® Statistics Version 22 (IBM^® Armonk). Variables are displayed as median and interquartile range (Q_1–Q₃) or number and percent. The Wilcoxon-signed-rank test was used to compare preoperative with postoperative values. All p-values <0.05 were considered statistically significant.

Results

Seventy-five consecutive patients were included in this prospective investigation. Baseline characteristics as well as intra- and perioperative results have been described in detail before and are displayed in Table 1.

Table 1.

Baseline Parameters (A), Intra- and Perioperative Parameters (B)

(a) Baseline parameters
Number of patients: 75
Age (years)	66 (62–73)
Prostate volume (mL)	41.0 (30.6–57.4)
PSA (ng/mL)	2.6 (1.5–4.9)
IPSS	16 (13–23)
QoL	4 (3–5)
Qmax (mL/s)	10.1 (8.0–16.0)
Residual volume (mL)	91.0 (12.0–170.0)
Indwelling catheter (n)	16 (21.3%)
ASA score (n)
I	6 (8.0%)
II	45 (60.0%)
III	24 (32.0%)
PAI or OAC (n)	26 (34.7%)
Acetylsalicylic acid (n)	26 (34.7%)
Clopidrogel (n)	0
Coumarin (n)	0
Positive urine culture (n)	28 (37.3%)
Indwelling catheter (n)	14 (50.0%)
No catheter (n)	14 (50.0%)
(b) Intra- and perioperative parameters
Operative time (min)	75.0 (60.0–90.0)
Anesthesia
Intubation (n)	58 (77.3%)
Spinal anesthesia (n)	17 (22.7%)
Blood transfusion (n)	0
Duration of catheterization (d)	3.0 (3.0–3.0)
Recatheterization (n)	10 (13.3%)
Urinary retention (n)	9 (12.0%)
Persistent hematuria (n)	1 (1.3%)
Stress urinary incontinence (n)	0

Data presented as median (interquartile range) or number (percent).

PSA = prostate-specific antigen; IPSS = international prostate symptom score; QoL = quality of life; Qmax = maximum urinary flow rate; ASA score = American Society of Anesthesiology score; PAI = platelet aggregation inhibitors; OAC = oral anticoagulation.

Median preoperative prostate volume was 41 mL (IQR: 30.6–57.4 mL). The absolute and relative prostate volume reduction over time is shown in Table 2. At the time of catheter removal, a significant volume reduction of 33.3% of the baseline volume was detectable (p < 0.001). The prostate volume decreased further, and after 12 months, the volume reduction was 52.2% (43.8–61.2% p = 0.01). After 3 years, a volume reduction of 50.7% was detectable, which was not significantly different compared with the reduction after 1 year.

Table 2.

Absolute and Relative Prostate Volume Reduction

Absolute volume reduction	p values ^a	p values ^b	Relative volume reduction	p values ^a	p values ^b
Postoperative
13.4 mL (8.3–19.9)	<0.001	n/a	33.3% (21.0–43.4)	<0.001	n/a
6 weeks
18.9 mL (12.4–27.2)	<0.001	<0.001	46.0% (37.0–54.3)	<0.001	<0.001
6 months
22.8 mL (13.7–29.5)	<0.001	<0.001	50.5% (41.9–58.0)	<0.001	<0.001
12 months
21.7 mL (13.3–30.0)	<0.001	0.01	52.2% (43.8–61.2)	<0.001	0.01
3 years
22.4 mL (14.7–29.3)	<0.001	0.38	50.7% (43.0–57.3)	<0.001	0.58

Data presented as median (interquartile range).

p-values <0.05 indicate a statistically significant difference compared to the baseline value (Wilcoxon signed-rank test).

p-values <0.05 indicate a statistically significant difference compared to the preceding value (Wilcoxon signed-rank test).

n/a = not available.

Clinical follow-up parameters are summarized in Table 3. As described previously, significant improvements of all investigated outcome parameters in comparison to baseline values were already detectable after 6 weeks (IPSS: 16 [13–23], QoL: 4 [3–5], Qmax: 10.1 mL/s [8.0–16.0 mL/s], RV: 91.0 mL [12.0–170.0 mL], and PSA: 2.6 ng/mL [1.5–4.9 ng/mL]). Afterwards, the outcome parameters remained stable with further improvements of the IPSS after 6 and 12 months and of the QoL domain after 6 months. Apart from a minor but statistically significant reduction of the maximum flow rate (16.6 vs 16.3 mL/s; p = 0.03), no significant changes in the investigated outcome parameters were detectable between 1 year and 3 years.

Table 3.

Clinical Outcome Parameters

IPSS (points)	QoL (points)	Qmax (mL/s)	RV (mL)	PSA (ng/mL)
Baseline
16 (13–23)	4 (3–5)	10.1 (8.0–16.0)	91.0 (12.0–170.0)	2.6 (1.5–4.9)
Postoperative
n/a	n/a	14.7 (9.5–22.9)^a	20.0 (0.0–50.0)^a	n/a
6 weeks
8 (5–13)^a	2 (1–3)^a	16.6 (11.2–25.7)^a	10.0 (0.0–21.5)^a,b	1.4 (0.7–2.7)^a
6 months
3 (2–9)^a,b	1 (1–2)^a,b	17.0 (11.8–22.1)^a	6.5 (0.0–30.6)^a	1.2 (0.5–2.5)^a
12 months
3 (1–6)^a,b	1 (1–2)^a	16.6 (10.7–26.8)^a	11.0 (0.0–47.5)^a	1.1 (0.5–2.5)^a
3 years
3 (1–8)^a	1 (1–2)^a	16.3 (13.4–19.8)^a,b	20.0 (0.0–80)^a	1.1 (0.6–2.5)^a

Data presented as median (interquartile range).

Indicates a statistically significant improvement compared to the baseline value (Wilcoxon signed-rank test).

Indicates a statistically significant improvement compared to the preceding value (Wilcoxon signed-rank test).

RV = postvoid residual volume; n/a = not available.

A symptomatic de novo urethral stricture was diagnosed in the postoperative follow-up in six patients (8.0%). Three patients developed a stricture during the first 12 months and three patients between 12 months and 3 years. Strictures were located in the membranous urethra in two patients, in the bulbar urethra in three patients, and at the meatus in one patient. With regard to surgeons' experience, more strictures were found in patients operated by senior residents (4 of 15 patients [26.6%]) compared with senior surgeons (2 of 60 patients [3.3%]). All patients were effectively treated by internal urethrotomy without the need for further intervention. A bladder neck contracture developed in five patients (6.6%) with a median preoperative prostate volume of 36.2 mL (range 30.6–56.3 mL). It was diagnosed after 4 months (n = 2), 14 months (n = 1), 15 months (n = 1), and 22 months (n = 1). Effective transurethral bladder neck incision was performed in all patients. In one patient, a urethrotomy and a bladder neck incision were performed simultaneously. Re-resections due to persistent or regrown adenoma were not necessary in any patient up to 3 years of follow-up.

Discussion

Our prospective investigation is the first to report three-year results following pure, contemporary BPV of the prostate. It confirms the promising results that have previously been reported by others and us with a shorter follow-up. Subjective patient satisfaction parameters (i.e., IPSS and QoL) as well as objective clinical outcome parameters (i.e., Qmax, RV) remained significantly improved over time. Due to a significant and stable prostate volume reduction of 50%, reoperations of persistent or regrown adenoma were not necessary. The only downside of the procedure identified so far is the rather high rate of de novo urethral strictures and bladder neck contractures.

Previously, deobstructive prostate surgery was often not performed in older patients with relevant comorbidities and in patients who were not allowed to stop their PAI or anticoagulation medication for the procedure. Especially older patients' monopolar TURP is associated with a significant morbidity.¹⁵ For this patient population, the bipolar technique offers an improved safety profile, particularly in terms of bleeding complications and absorption of hypotonic irrigation fluid. Our group and others have shown that BPV is a low morbidity procedure with an excellent short-term outcome.^7,16 Bleeding complications, including reoperations due to persistent hematuria or blood transfusions, were not observed at all in our cohort.

However, not only immediate intra- or perioperative complications are important to assess the value of a novel procedure for prostatic deobstruction. The mid- and long-term efficacy is affected by reinterventions due symptoms caused by persistent or regrown adenoma tissue and other relevant complications such as urethral strictures or bladder neck contractures. Thus, they are important parameters to assess during follow-up of these procedures.

Other groups reported a retreatment rate of 3.5% within 18 months following pure BPV, which is comparable to the rate following conventional TURP.¹² A nation-wide study, including 20.671 men followed for up to 8 years after TURP demonstrated a cumulative retreatment rate of 2.9%, 5.8%, and 7.4% at 1, 5, and 8 years, respectively.⁴ Data from randomized controlled trials showed reoperation rates for bipolar TURP of 9% after 5 years and 11.8% after 8 years.^17,18 Retreatment rates following laser vaporization of the first-generation 80-W GreenLight laser (80 W), another alternative ablation technique for patients with increased bleeding risks, have been reported to be as high as 25% after 5 years.¹⁹ A retrospective analysis of the more powerful 120-W GreenLight laser demonstrated an overall retreatment rate of 4.3% after 5 years.²⁰ Others reported a higher retreatment rate of already 8.9% after 3 years following 120-W laser ablation.²¹ Our 3 D ultrasound investigation detected a volume reduction of 43.3% 12 months after 120-W GreenLight laser vaporization.¹⁴

The absence of re-resections in our patient cohort underlines the effectiveness of the BPV procedure. Compared to published data for either monopolar or bipolar TURP or vaporization using the GreenLight laser, our results can be considered superior.²² A reason for these excellent results might be the good overview due to minimal intraoperative bleeding, which allows for a well-controlled ablation until the end of the procedure. The relative prostate volume reduction of more than 50% in our cohort supports this hypothesis.

Although reoperations due to persistent or regrown adenoma were not necessary in our cohort, a relevant number of patients had to undergo additional procedures due to symptomatic urethral strictures or bladder neck contractures. Both the rates of urethral strictures (8%) and of bladder neck contractures (6.6%) seem to be rather high, when compared to the published rates after monopolar or bipolar TURP.²³ In our cohort, strictures were mostly located in the bulbomembranous urethra. A potential explanation for the high rate of urethral strictures may be the more extensive movement that needs to be performed during BPV compared to transurethral resections. To remove the same amount of tissue, the spherical BPV electrode has to be moved more often over the prostatic tissue than the resection loop. These movements might result in more microtraumata to the urethra and thus increase the rate of urethral strictures. Another explanation might be the use of a relatively large resectoscope (26F) in our series. It has been shown that the use of larger diameter resectoscopes may cause an increase in the incidence of urethral strictures.²⁴ Using the new generation oval button electrode with an adapted shape and a larger surface might enable more effective tissue vaporization and thus require less movements of the resectoscope. In addition, the use of resectoscopes with smaller diameters might also reduce shear stress to the urethra during surgery. Our finding that strictures occurred more often in patients operated by senior residents underlines the hypothesis that more extensive movements of the resectosocpe due to a lower experience level may lead to higher stricture rates.

A reason for the rather high number of bladder neck contractures in our series might be the coagulation depth of the bipolar electrode. It has been shown that the coagulation zone after BPV is larger than after monopolar TURP. This results in better tissue coagulation but might also lead to a more pronounced scar formation, which can result in contractures at the bladder neck.^25,26 Due to the repeated movements of the vaporization electrode over the tissue, coagulation depth and scar formation might be even more pronounced after BPV. Another known risk factor of bladder neck contracture is the size of the prostate. Given the higher risk of bladder neck contractures in smaller prostates, transurethral incision of the prostate (TUIP) instead of TURP is recommended in small prostates. However, the prostate size of the patients who developed a bladder neck contracture is not particularly small in our patient cohort (range 30.6–56.3 mL).

When interpreting the rate of urethral strictures and bladder neck contractures in the context of published results, it has to be taken into consideration that underreporting of urethral strictures and bladder neck contractures has been identified to be an issue in several published series.³ In contrast to these series, assessment of postoperative complications has been systematically performed in a prospective manner in the present study.

Since this is the first report of volume reduction and clinical outcome with a follow-up of 3 years after BPV, the reintervention rate found in this study can only be compared to studies with a shorter follow-up. The longest available follow-up of 18 months has been published by Geavlete et al.¹² They observed urethral strictures in 4.7% and bladder neck contractures in 0.6% of their cohort. In our series, half of the complications were observed within the first 12 months follow-up and half after 12 months follow-up.

Regarding the clinical outcome after BPV as assessed by the IPSS, QoL, Qmax, RV, and PSA, we observed a significant and persistent improvement of all parameters up to 3 years. Our results are well comparable to reported data after conventional monopolar and bipolar TURP.^1,23

There are limitations to our investigation, which have already been reported, including the lack of a control group.⁸ This is a single-center, single-arm investigation. To confirm the validity of our results a comparative multicenter study with even longer follow-up is needed. However, as midterm results following BPV are still lacking, our study adds important new information to the field of deobstructive prostate surgery.

Conclusion

Three years after pure BPV of the prostate a durable prostate volume reduction in combination with a stable improvement of functional outcome parameters was detectable in our prospective study. The low morbidity of the procedure and the possibility to perform BPV under ongoing platelet aggregation inhibition confirms its role as minimally invasive alternative to conventional TURP.

Footnotes

Acknowledgment

The authors acknowledge Ms. Alexandra Veloudios for the excellent organization of the patient care during this study.

Author Disclosure Statement

The authors declare that no competing financial interests exist.

Abbreviations Used

References

Gratzke

, Bachmann

, Descazeaud

, et al. EAU guidelines on the assessment of non-neurogenic male lower urinary tract symptoms including benign prostatic obstruction. Eur Urol, 2015; 67:1099–1109.

Reich

, Gratzke

, Stief

. Techniques and long-term results of surgical procedures for BPH. Eur Urol, 2006; 49:970–978; discussion 970–978.

Cornu

, Ahyai

, Bachmann

, et al. A systematic review and meta-analysis of functional outcomes and complications following transurethral procedures for lower urinary tract symptoms resulting from benign prostatic obstruction: An update. Eur Urol, 2015; 67:1066–1096.

Madersbacher

, Lackner

, Brössner

, Röhlich

, Stancik

, Willinger

, Schatzl

. Reoperation, myocardial infarction and mortality after transurethral and open prostatectomy: A nation-wide, long-term analysis of 23,123 cases. Eur Urol, 2005; 47:499–504.

Varkarakis

, Bartsch

, Horninger

. Long-term morbidity and mortality of transurethral prostatectomy: A 10-year follow-up. Prostate, 2004; 58:248–251.

Mainous

, Tanner

, Shorr

, Limacher

. Use of aspirin for primary and secondary cardiovascular disease prevention in the United States, 2011–2012. J Am Heart Assoc, 2014; 3: pii: e000989.

Kranzbühler

, Gross

, Fankhauser

, et al. Prostate volume reduction following pure transurethral bipolar plasma vaporization and conventional transurethral resection of the prostate: A prospective investigation using transrectal 3D ultrasound volumetry. World J Urol, 2017; 35:429–435.

Kranzbühler

, Wettstein

, Fankhauser

, et al. Pure Bipolar Plasma Vaporization of the Prostate: The Zurich Experience. J Endourol, 2013; 27:1261–1266.

Geavlete

, Multescu

, Dragutescu

, Jecu

, Georgescu

, Geavlete

. Transurethral resection (TUR) in saline plasma vaporization of the prostate vs standard TUR of the prostate: ‘the better choice’ in benign prostatic hyperplasia?. BJU Int, 2010; 106:1695–1699.

10.

Reich

, Schlenker

, Gratzke

, Tilki

, Riecken

, Stief

, Seitz

, Bachmann

. Plasma vaporisation of the prostate: Initial clinical results. Eur Urol, 2010; 57:693–698.

11.

Robert

, Descazeaud

, Delongchamps

, et al. Transurethral plasma vaporization of the prostate: 3-month functional outcome and complications. BJU Int, 2012; 110:1–6.

12.

Geavlete

, Georgescu

, Multescu

, Stanescu

, Jecu

, Geavlete

. Bipolar plasma vaporization vs monopolar and bipolar TURP-A prospective, randomized, long-term comparison. Urology, 2011; 78:930–935.

13.

Antunes

, Srougi

, Coelho

, Leite

, Freire

GdC

. Transurethral resection of the prostate for the treatment of lower urinary tract symptoms related to benign prostatic hyperplasia: How much should be resected?. Int Braz J Urol, 2009; 35:683–689; discussion 689–691.

14.

Hermanns

, Gross

, Kranzbühler

, et al. Ablative efficiency of 532-nm laser vaporization compared to transurethral resection of the prostate: Results from a prospective three-dimensional ultrasound volumetry study. World J Urol, 2014; 32:1267–1274.

15.

Evrard

P-L

, Mongiat-Artus

, Desgrandchamps

. Morbi-mortality of transurethral resection of the prostate in patients aged 75 and over. Prog Urol, 2017; 27:312–318.

16.

Geavlete

, Stanescu

, Moldoveanu

, et al. Continuous vs conventional bipolar plasma vaporisation of the prostate and standard monopolar resection: A prospective, randomised comparison of a new technological advance. BJU Int, 2014:113:288–295.

17.

Zhu

, Chen

, Yang

, Wu

, Ge

, Wu

, Liao

, Tan

. Electrosurgical enucleation versus bipolar transurethral resection for prostates larger than 70 ml: A prospective, randomized trial with 5-year followup. J Urol, 2013; 189:1427–1431.

18.

Muslumanoglu

, Yuruk

, Binbay

, Akman

. Transurethral resection of prostate with plasmakinetic energy: 100 months results of a prospective randomized trial. BJU Int, 2012; 110:546–549.

19.

Elshal

, Elmansy

, Elhilali

. Two laser ablation techniques for a prostate less than 60 mL: Lessons learned 70 months after a randomized controlled trial. Urology, 2013; 82:416–424.

20.

Park

, Cho

, Jeong

, Son

. 5-year long-term efficacy of 120-W GreenLight photoselective vaporization of the prostate for benign prostate hyperplasia. PLoS One, 2017; 12:e0184442.

21.

Guo

, Müller

, Bonkat

, Püschel

, Gasser

, Bachmann

, Rieken

. GreenLight laser vs diode laser vaporization of the prostate: 3-year results of a prospective nonrandomized study. J Endourol, 2015; 29:449–454.

22.

Rieken

, Bachmann

, Shariat

. Long-term follow-up data more than 5 years after surgical management of benign prostate obstruction: Who stands the test of time?. Curr Opin Urol, 2016; 26:22–27.

23.

Mamoulakis

, Ubbink

, de la Rosette

JJMCH

. Bipolar versus monopolar transurethral resection of the prostate: A systematic review and meta-analysis of randomized controlled trials. Eur Urol, 2009; 56:798–809.

24.

Günes

, Keles

, Kaya

, et al. Does resectoscope size play a role in formation of urethral stricture following transurethral prostate resection?. Int Braz J Urol, 2015; 41:744–749.

25.

Maddox

, Pareek

, Al Ekish

, Thavaseelan

, Mehta

, Mangray

, Haleblian

. Histopathologic changes after bipolar resection of the prostate: Depth of penetration of bipolar thermal injury. J Endourol, 2012; 26:1367–1371.

26.

Mamoulakis

, Schulze

, Skolarikos

, Alivizatos

, Scarpa

, Rassweiler

, de la Rosette

JJMCH

, Scoffone

. Midterm results from an international multicentre randomised controlled trial comparing bipolar with monopolar transurethral resection of the prostate. Eur Urol, 2013; 63:667–676.