Novel Thulium Fiber Laser for Enucleation of Prostate: A Retrospective Comparison with Open Simple Prostatectomy

Abstract

Introduction:

The objective of this study was to assess the efficacy and safety of novel thulium fiber laser enucleation of the prostate (ThuFLEP) vs conventional open simple retropubic prostatectomy (OP) for large volume benign prostatic hyperplasia (BPH).

Methods:

We performed a retrospective review of patients who underwent surgical treatment for large volume BPH (>80 cc) from 2015 to 2017. Preoperative patient examination included the assessment of functional parameters: International Prostate Symptom Score (IPSS), quality of life (QoL), maximum urine flow rate (Q_max), and postvoid residual urine volume. The hemoglobin level was measured before and after the operation.

Results:

A total of 130 patients were included in the study. Of these, 40 patients underwent OP, and 90 patients underwent ThuFLEP. Groups were similar in terms of preoperative functional parameters (IPSS, QoL, and Q_max). The mean operative time was comparable for both procedures (p = 0.285) as well as the mass of adenomatous tissue resected (p = 0.412). Resection speed was comparable (OP—0.9 vs ThuFLEP—1.0 g/min, p = 0.52). Patients in OP had significantly longer catheterization time and length of hospital stay (9.0 days vs 3.3 days, p < 0.001). At 6 months, stress urinary incontinence rate were 1.1% after ThuFLEP and 2.5% after OP.

Conclusions:

Despite the equally high efficacy of both modalities for infravesical obstruction due to BPH, ThuFLEP is a minimally invasive modality that is associated with a shorter hospital stay, a significantly greater return to normal activities, and a considerable reduction in rehabilitation time. Our results demonstrated that the ThuFLEP is a highly efficacious, minimally invasive modality for the management of BPH in large volume glands (>80 cc).

Introduction

Since the introduction of Frayer's open simple retropubic prostatectomy (OP) more than 100 years ago, and Millin's OP in 1945,^1,2 there have been significant technologic advancements transforming the traditional open approach for benign prostatic hyperplasia (BPH) to minimally invasive endoscopic modalities. However, OP still remains one of the preferred surgical approaches in patients with BPH of >80 cc in size.³

The adoption of holmium laser enucleation of the prostate (HoLEP) within the last two decades has allowed for the endoscopic enucleation of BPH independent of prostate size.^3
–5 Although the rate of recurrences after HoLEP does not exceed 5%, HoLEP is considered a technically challenging procedure. It is associated with a flat learning curve, requiring on average 50 to 60 procedures to reach the plateau.⁶ This has provoked surgeons to investigate alternative efficacious laser enucleation techniques for the resection of large-sized BPH.^7
–9 In light of this search, the thulium fiber (Tm-fiber) laser is of great interest.

Tm-fiber laser is a novel technology that has several advantages over other widely used lasers. Compared to Thulium:YAG (Tm:YAG) laser, Tm-fiber laser is both smaller in size and laser wavelength. Tm-fiber laser has a wavelength of 1940 nm (70 nm less than Tm:YAG), which is potentially correlated with reduced depth of penetration and an increase in laser energy adsorption in tissue.^3,10 Tm-fiber laser minimizes the depth of penetration by two times less than Tm:YAG, allowing for more accurate and precise incisions, as well as reduced tissue damage.⁷

Since the launch of the concept, Tm-fiber laser has been used for enucleation of prostate and urolithiasis. Thulium fiber laser enucleation of the prostate (ThuFLEP) has demonstrated both efficacy and safety in the treatment of large BPH, leading to a reduction of the prostate volume up to 90%.^11,12 Moreover, thulium enucleation demonstrates a significantly shorter learning curve compared to HoLEP.^6,13,14 There is a substantial body of literature comparing thulium laser enucleation of the prostate (ThuLEP) and other transurethral modalities such as transurethral resection of the prostate (TURP) and HoLEP. However, to the best of our knowledge, there are few studies comparing ThuFLEP and traditional OP.

The objective of this study was to assess and compare the efficacy and safety of ThuFLEP vs conventional OP for large volume BPH.

Methods

We performed a retrospective chart review of patients who underwent either ThuFLEP or OP for BPH >80 cc in 2015 to 2017. Group 1 patients (n = 40) underwent open prostatectomy, and group 2 patients (n = 90) underwent ThuFLEP. The main inclusion criteria were as follows: International Prostate Symptom Score (IPSS) >20 or maximum urine flow rate (Q_max) <10 mL/s. Patients with a suprapubic tube, bladder calculi, and diagnosed with prostate cancer were excluded from this analysis. Patient demographics and clinical characteristics were recorded and compared between the two groups. Preoperative patient evaluation included digital rectal examination, transrectal ultrasound examination of the prostate volume, and assessment of functional parameters, including the IPSS questionnaire, IPSS-quality-of-life (QoL) questionnaire, Q_max, and postvoid residual urine (PVRU) volume. The hemoglobin level was measured before and after the operation.

Surgical techniques

The ThuFLEP technique was performed as the previously described two- or one-lobe(s) technique.^7,8 We used a No. 26F resectoscope providing continuous, low pressure, Iglesias-type irrigation (Karl Storz, Germany; Richard Wolf, Germany; ELEPS, Russia) and Urolase 120W 1940 nm thulium fiber laser (NTO IRE-POLUS, Russia); and a 600-μm laser fiber. The mean power used was 60W. Adenomatous tissue was excised using a straight cystoscope and morcellators (Piranha; Richard Wolf) or (ELEPS). All ThuFLEP procedures were performed by a single, highly experienced surgeon in EEP (HoLEP, electoenucleation) (surgeon D.E.).

Millin's open prostatectomy approach is preceded by bladder drainage via Foley urethral catheter. The access to the Retzius space is achieved by a mid-inferior incision. The anterior aspect of the bladder neck and prostate is then mobilized. The prostate gland is sutured and ligated while grasping the prostatic vessels above and below the suspected transverse incision of the gland. The lateral and medial hyperplastic lobes are then enucleated. The prostatic urethra is then excised after its dissection, along with the hyperplastic tissue of the prostatic lobes. After bladder neck incision, several sutures are applied on the posterior lip of the bladder neck for eversion and hemostasis. The bladder is then drained with a three-way catheter and the prostate is stitched using a double-row suture. The Retzius space is drained through a counterincision, and the wound is closed layer by layer.² All open interventions were performed by a single skilled surgeon (M.E.).

Statistical analyses

Continuous variables were compared using a one-way analysis of variance test. Categorical variables were compared via Chi-square tests. Nonparametric variables were compared using Kolmogorov–Smirnov and Kruskal–Wallis tests. Post hoc analysis was performed with the Mann–Whitney U test. All statistical analyses were carried out using SPSS Statistics, version 22.0 (SPSS, Inc., Chicago, IL). A p-value of <0.05 was considered statistically significant.

Results

A total of 130 patients were included in this study. Patient demographics and clinical characteristics of two groups are shown in Table 1. Preoperative assessment revealed only one difference between the ThuFLEP and OP groups, with IPSS score being higher in the OP group. Perioperative variables between the two groups are shown in Table 2. The mean operative time was comparable for both procedures (p = 0.285), and the mass of adenomatous tissue resected during the course of both interventions showed no significant change (p = 0.412). Patients subjected to OP had significantly higher blood loss demonstrated by a significant reduction in hemoglobin levels postoperatively, when compared to patients subject to ThuFLEP. ThuFLEP patients had a mean hemoglobin change of 2.8 g/dL after OP vs 1.0 g/dL after ThuFLEP (p < 0.001). The average catheterization time following OP was 6.4 days, while the catheter in most patients following ThuFLEP (79%) was removed within the first 24 hours. The OP group had significantly longer hospital stays compared with ThuFLEP (9.0 days vs 3.3 days, respectively; p < 0.001).

Table 1.

Preoperative Data

	OP (n = 40)	ThuFLEP (n = 90)	P
Age (mean, years, SD)	67.0 ± 1.0	67.4 ± 7.7	0.771
Prostatic volume (mean, cc, SD)	114.1 ± 38.9	127.8 ± 40.2	0.071
IPSS, score	24.6 ± 3.3	21.8 ± 1.1	<0.001^*
QoL, score	4.5 ± 1.5	3.9 ± 0.8	0.108
Q_max, mL/s	7.9 ± 2.8	7.5 ± 1.9	0.214
PVRU, mL	65.8 ± 19.5	73.4 ± 29.4	0.133

Statistically significant difference.

IPSS = International Prostate Symptom Score; OP = open prostatectomy; PVRU = postvoid residual urine; Q_max = maximum urine flow rate; QoL = quality of life; SD = standard deviation; ThuFLEP = thulium fiber laser enucleation of the prostate.

Table 2.

Intra- and Perioperative Parameters

	OP (n = 40)	ThuFLEP (n = 90)	p
Operation time (mean, minutes, SD)	109.5 ± 11.03	103.2 ± 36.6	0.285
Mass of resected tissue, (mean, g, SD)	99.2 ± 35.3	104.5 ± 33.4	0.412
Resection speed, g/min	0.9	1.01	0.52
Catheterization time, (mean, days, SD)	6.4 ± 1.5	1.4 ± 0.6	<0.001^*
Hospital stay, (mean, days, SD)	9.0 ± 2.4	3.3 ± 0.6	<0.001^*
hemoglobin level before the surgery, (mean, g/dL, SD)	13.4 ± 1.2	13.6 ± 1.1	0.242
hemoglobin level after the surgery (mean, g/dL, SD)	10.6 ± 1.6	12.7 ± 1.1	<0.001^*

Statistically significant difference.

Patients complaining of stress urinary incontinence (SUI) underwent a pad test to assess the degree of incontinence. Short-term SUI (mild) was noted in 6 (6.7%) patients after ThuFLEP vs 2 (5.0%) patients after OP (Table 3). At 3-month follow-up appointments, the rate of transient SUI in the OP group was 2.5% (1 patient) and 4.4% (4 patients) in the ThuFLEP group (p = 0.598). At 6-month follow-up appointments, the number of patients with transient SUI decreased to 1 in each group. Five (12.5%) patients developed urgency following OP vs 4 (4.4%) patients in the ThuFLEP group. Three months after surgery, the rate of urgency decreased to 7.5% (3 patients) in the OP group and to 1.1% (1 patient) in the ThuFLEP group. Six months postoperatively, one patient in both the OP and the ThuFLEP group had complaints of urgency.

Table 3.

Complications

Complication	Grade	OP (n = 40)	ThuFLEP (n = 90)	p
Urinary tract infection, n (%)	I	5 (12.5)	5 (5.5)	0.173
Stress-induced incontinence, n (%)	I	2 (5.0)	6 (6.7)	0.718
Urgent incontinence, n (%)	I	5 (12.5)	4 (4.4)	0.096
Postoperative bleeding, n (%)	I	3 (7.5)	3 (3.3)	0.102
Bladder tamponade, n (%)	II	2 (5.0)	2 (2.2)	0.151
Blood transfusion, n (%)	II	2 (5.0)	0	0.033^*
Delayed morcellation, n (%)	III	0	3 (3.3)	0.346

Statistically significant difference.

One of the most common complications was bleeding: 2 (5%) patients who underwent OP experienced immediate intraoperative and postoperative bleeding requiring a blood transfusion. Postoperative bleeding presented in 3 (3.3%) ThuFLEP patients, which was managed conservatively with prolonged bladder irrigation. In the event of intraoperative bleeding control insufficiency (including electrocoagulation), a 3-way Foley catheter with an irrigation system was placed upon completing the enucleation. Then, after 48 hours, morcellation was performed. Morcellation was postponed in 3 (3.3%) of the ThuFLEP procedures (Table 3).

After 6 months, a control examination was conducted to investigate the IPSS, QoL, Q_max, and the volume of residual urine of each patient. All the parameter values demonstrated a significant improvement in both groups (for IPSS, Q_max, and PVR p < 0.001) (Table 4), exhibiting the effective removal of the BPH-associated infravesical obstruction. PSA level, as the possible marker for completeness of adenoma enucleation,¹⁵ after 6 months was 0.84 ± 0.5 after ThuFLEP and 0.90 ± 0.5 after OP (p = 0.802), signifying that both procedures are equally efficacious in BPH removal.

Table 4.

Postoperative Outcomes at 6 Months

	IPSS preoperative, score	IPSS postoperative, score	p	QoL preoperative, score	QoL postoperative, score	p	Q_max, preoperative, mL/s	Q_max, postoperative, mL/s	p	PVR preoperative, mL	PVR postoperative, mL	p
ThuFLEP (n = 90)	21.8 ± 1.1	10.7 ± 2.6	<0.001	3.9 ± 0.8	1,6 ± 0.7	0.032	7.5 ± 1.9	17,7 ± 2,3	<0.001	73.4 ± 29.4	16,8 ± 10,9	<0.001
OP (n = 40)	24.6 ± 3.3	10.6 ± 3.4	<0.001	4.5 ± 1.5	1.5 ± 0.7	0.098	7.9 ± 2.8	17,2 ± 2,7	<0.001	65.8 ± 19.5	15,1 ± 14,0	<0.001
P	<0.001	0.996		0.108	0.432		0.214	0.23		0.133	0.454

PVR = postvoid residual.

Discussion

Since the introduction of OP >100 years ago, there have been many modifications to improve the technique and reduce morbidity associated with the procedure.^1,2 Despite the advancements, OP remains a highly invasive and morbid procedure, causing longer hospital stays and an increased risk of infection compared with transurethral interventions.^1,3

With the advancement of endoscopic technology, transurethral, minimally invasive modalities have become the standard of care for men with BPH regardless of prostate size. HoLEP and TURP have become one of the most widely used procedures for lower urinary tract symptoms (LUTS) due to BPH. There have been many comparison studies between the OP, HoLEP, and TURP.¹⁶ These studies over the last two decades have concluded that TURP and, most recently, HoLEP have become the gold standard for surgical management of BPH independent of prostate size. However, HoLEP is considered a technically challenging procedure with a flat learning curve. In the hands of a well-trained and experienced surgeon, the outcomes have been shown to be excellent.

Thulium laser technology has become an increasingly popular approach since its introduction in 2005.^17,18 Initially used as a thulium vapoenucleation of the prostate (ThuVEP) technique with excessive use of a laser, this technology was subsequently introduced and modified to blunt enucleation technique (ThuLEP).^19,20 Thulium fiber laser technology differs from Tm:YAG and Holmium:YAG (Ho:YAG) in similar aspects. The shallower penetration depth of Tm-fiber laser (two times lower than in Tm:YAG laser) allows for a decrease in the carbonization rate and an overall much more accurate incision compared to all other enucleation techniques.²¹ ThuFLEP has already shown its superior efficiency in comparison to other techniques of endoscopic enucleation of the prostate (holmium and electroenucleation techniques), proving its place in clinical practice.⁷

In our clinical practice, ThuFLEP is usually performed at 60W. However, when we reached the verumontanum zone, the power was decreased to 30W as a preventive measure to preserve continence. This step does not make the incision at the verumontanum harder to perform and minimizes the chance of external sphincter damage.

During the 6-month postoperative follow-up appointments, all the patients reported a considerable improvement in the quality of urination, regardless of the type of surgical intervention. These findings were confirmed by improved LUTS recorded at this time period (IPSS, QoL, Q_max, and PVRU volume). However, our study indicated that ThuFLEP was associated with a lower rate of postoperative complications when compared with open prostatectomy. For example, the postoperative urgency rate was considerably lower after ThuFLEP than after OP (after removal of the catheter and after 3 months). The duration of SUI in the majority of the patients did not exceed 3 months in either group.

In addition to higher rates of postoperative complications, high postoperative morbidity rates are another disadvantage of OP.^22,23 As a minimally invasive technique, ThuFLEP avoids the need for urinary tract dissection and rarely requires catheter placement for >1 day, theoretically resulting in a reduced risk of infectious catheter-associated complications.^24,25

Furthermore, our results indicated that ThuFLEP significantly reduces intraoperative and postoperative blood loss when compared with open simple prostatectomy. This is reflected in the smaller change in postoperative hemoglobin levels seen in patients who underwent ThuFLEP compared to that of patients subjected to OP. Moreover, OP caused an episode of postoperative bleeding that warranted transfusion of blood components. Several other studies reported similar results.^10,26,27 Bach et al.²⁸ attributes the reduced blood loss associated with thulium enucleation to the continuous thulium laser wave smoothly dissecting and vaporizing tissue, which, in turn, facilitates a better hemostatic effect. As previously mentioned in articles on other EEP techniques (HoLEP), its speed and efficacy increase with the prostate size, while OP speed remains constant in prostates of all sizes.²⁷ It should be noted that, in addition to reliable hemostasis, a small depth of penetration (<2 μm) coupled with the continuous wave of the thulium laser fiber leads to precise and instantaneous tissue excision. This allows for the resection of adenomatous nodes with no damage to the underlying tissues.^7,10

ThuFLEP also demonstrates several advantages over other fiber laser-based surgical approaches, mostly due to the use of the Tm-fiber laser, which is different from the Tm:YAG laser previously used. According to EAU guidelines,³ the thulium laser improves hemostasis, reduces damage to the underlying tissues, and allows the capsule and the neurovascular bundles intimately adjacent to the posterolateral surface of the prostate to remain intact. Thulium fiber laser technology enables even smaller penetration into tissues and temperature rise. Moreover, ThuFLEP reduces the carbonization effect compared to Tm:YAG laser (ThuLEP).¹⁰ ThuFLEP allows for the efficacious separation of prostate tissues and a rapid restoration of the enucleation plane if it is lost. Holmium laser enucleation, however, requires considerable time to restore the plane.^14,29 This advantage of the Tm-fiber laser is determined by two main features. First, the thulium fiber laser is a continuous-wave laser, whereas the holmium laser operates in a pulsed mode. As a result, tissue separation is achieved by the formation of steam bubbles at the tip of a laser fiber.³⁰ Second, Tm-fiber laser, due to a wavelength of 1.94 μm, is four to five times better absorbed in water. This only penetrates the tissues at a shallow depth (Tm-fiber—<0.2 mm; Ho:YAG—0.4–0.7 mm).³¹ Therefore, while such a well-established laser for enucleation as Ho:YAG leads to thermomechanical tissue separation (combining high temperature around the fiber tip with large amounts of vapor bubbles separating adenoma with mechanical power), the incision created by the thulium laser is more accurate and allows for quick identification of the enucleation plane. This uniquely small size of the coagulation zone produced by the Tm-fiber laser makes it optimal for typical vessel coagulation.³²

This fundamental difference in the laser properties altered our approach to surgery. The technique used in our study (ThuFLEP) is based on laser incision combined with small portion of mechanical enucleation (in approximate ration of 70%–30%), whereas the ThuVEP technique is based on massive tissue vaporization, and ThuLEP mostly uses mechanical movement. Such an approach allows a faster surgery performance with a minimal rate of capsule damage and enucleation plane loss. Another advantage is the shorter learning curve of ThuFLEP. It became possible because HoLEP offers more challenges when trying to regain the enucleation layer because of its pulsed wave and laser-induced steam. This may lead to loss of the enucleation plane during the EEP. Identifying and maintaining the enucleation plane are paramount for effective surgery. The Tm-fiber laser more effectively allows for this than Ho:YAG (due to more precise tissue cutting), leading to a lower rate of hemorrhage and prostate capsule injury at the beginning of the learning curve. This may imply that it is the perfect tool for novice surgeons who train for EEP.¹⁴

In three patients in the ThuFLEP group, the morcellation was done as the second step of the surgery 1 day after enucleation. This happened due to significant bleeding from the capsular veins, which occurred during laser enucleation. Coagulation with the laser and electrocoagulation was insufficient. Continuous bleeding led to low visibility, which is inadmissible during morcellation. These patients underwent bladder drainage with Foley catheter, and morcellation was delayed.

Limitations of our study include its retrospective nature, and a relatively small number of patients in the OP group, which was due to complete substitution of this technique with EEP at our institution. There were several factors that affected the number of patients in the OP group and in the ThuFLEP group. First was the timing of the technology, as OP was the gold standard before the introduction of fiber laser techniques. Several other factors included the size of the prostate and patient preference. Another limitation to this study is that such dramatic differences in catheterization (e.g., hospital stay) in OP and ThuFLEP groups were mostly due to standard practices of open surgery in Russia. Nevertheless, in a number of surgeries, the catheter placement in OP was 3 to 4 days, with a hospitalization rate of 5 to 6 days, which still significantly differs from the laser enucleation postoperative factors.

Conclusions

Both OP and ThuFLEP are efficacious surgical modalities for the management of infravesical obstruction due to large-sized BPH. Our single-center analysis demonstrated that the complication rate after OP is higher than ThuFLEP. Moreover, ThuFLEP is a minimally invasive modality that allows for earlier patient discharge, considerably reducing the length of hospital stay and resumption of normal activities. Further prospective, randomized studies are needed to confirm our findings that ThuFLEP is a highly efficacious minimally invasive modality for the management of BPH in large glands (>80 cc).

Footnotes

Acknowledgment

All authors state that they have no commercial interests in this article.

Ethical Approval

For this type of study formal consent is not required.

Informed Consent

Informed consent was obtained from all individual participants included in the study.

Authors' Contributions

D.E.—article writing/editing; protocol/project development. L.R.—protocol/project development. M.T.—article writing/editing; data analysis and collection. M.E.—article editing. O.S.—data analysis. J.I.—data collection and management. T.C.—article editing. Z.O.—article writing/editing. P.G.—protocol/project development.

Author Disclosure Statement

All authors state that they have no disclosure that might potentially bias the work.

Abbreviations Used

References

Freyer

. A new method of performing perineal prostatectomy. Br Med J, 1900; 1:698–699.

Millin

. Retropubic prostatectomy; a new extravesical technique; report of 20 cases. Lancet, 1945; 2:693–696.

Gravas

, Drake

, Gacci

, et al. Management of Non-neurogenic Male Lower Urinary Tract Symptoms (LUTS), Incl. Benign Prostatic Obstruction (BPO). The Netherlands: EAU Guidelines Office, 2018.

Naspro

, Suardi

, Salonia

, et al. Holmium laser enucleation of the prostate versus open prostatectomy for prostates >70 g: 24-Month follow-up. Eur Urol, 2006; 50:563–568.

Kuntz

, Lehrich

, Ahyai

. Holmium laser enucleation of the prostate versus open prostatectomy for prostates greater than 100 grams: 5-Year follow-up results of a randomised clinical trial. Eur Urol, 2008; 53:160–168.

Brunckhorst

, Ahmed

, Nehikhare

, Marra

, Challacombe

, Popert

. Evaluation of the learning curve for holmium laser enucleation of the prostate using multiple outcome measures. Urology, 2015; 86:824–829.

Enikeev

, Glybochko

, Okhunov

, et al. Retrospective analysis of short-term outcomes after monopolar versus laser endoscopic enucleation of the prostate: A single center experience. J Endourol, 2018; 32:417–423.

Iacono

, Prezioso

, Di Lauro

, et al. Efficacy and safety profile of a novel technique, ThuLEP (Thulium laser enucleation of the prostate) for the treatment of benign prostate hypertrophy. Our experience on 148 patients. BMC Surg, 2012; 12(Suppl 1):S21.

Krambeck

, Handa

, Lingeman

. Holmium laser enucleation of the prostate for prostates larger than 175 grams. J Endourol, 2010; 24:433–437.

10.

Fried

, Murray

. High-power thulium fiber laser ablation of urinary tissues at 1.94 microm. J Endourol, 2005; 19:25–31.

11.

Bach

, Herrmann

TRW

, Haecker

, Michel

, Gross

. Thulium:yttrium–aluminium-garnet laser prostatectomy in men with refractory urinary retention. BJU Int, 2009; 104:361–364.

12.

Xia

, Zhuo

, Sun

, Han

, Shao

, Zhang

. Thulium laser versus standard transurethral resection of the prostate: A randomized prospective trial. Eur Urol, 2008; 53:382–389.

13.

Saredi

, Pirola

, Pacchetti

, Lovisolo

, Borroni

, Sembenini

, Marconi

. Evaluation of the learning curve for thulium laser enucleation of the prostate with the aid of a simulator tool but without tutoring: Comparison of two surgeons with different levels of endoscopic experience. BMC Urol, 2015; 15:49.

14.

Enikeev

, Glybochko

, Rapoport

, Gahan

, Gazimiev

, Spivak

, Enikeev

, Taratkin

. A Randomized Trial Comparing The Learning Curve of 3 Endoscopic Enucleation Techniques (HoLEP, ThuFLEP, and MEP) for BPH Using Mentoring Approach-Initial Results. Urology, 2018; 121:51–57.

15.

Herrmann

TRW

, Bach

, Imkamp

, Georgiou

, Burchardt

, Oelke

, Gross

. Thulium laser enucleation of the prostate (ThuLEP): Transurethral anatomical prostatectomy with laser support. Introduction of a novel technique for the treatment of benign prostatic obstruction. World J Urol, 2010; 28:45–51.

16.

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.

17.

Xia

, Zhang

, Lu

, Sun

, Zhang

, Zhu

, Li

. Thulium laser resection of prostate-tangerine technique in treatment of benign prostate hyperplasia. Zhonghua Yi Xue Za Zhi, 2005; 85:3225–3228.

18.

Wendt-Nordahl

, Huckele

, Honeck

, Alken

, Knoll

, Michel

, Häcker

. Systematic evaluation of a recently introduced 2-microm continuous-wave thulium laser for vaporesection of the prostate. J Endourol, 2008; 22:1041–1046.

19.

Netsch

, Stoehrer

, Brüning

, Gabuev

, Bach

, Herrmann

TRW

, Gross

. Safety and effectiveness of Thulium VapoEnucleation of the prostate (ThuVEP) in patients on anticoagulant therapy. World J Urol, 2014; 32:165–172.

20.

Kyriazis

, Świniarski

, Jutzi

, et al. Transurethral anatomical enucleation of the prostate with Tm:YAG support (ThuLEP): Review of the literature on a novel surgical approach in the management of benign prostatic enlargement. World J Urol, 2015; 33:525–530.

21.

Enikeev

, Glybochko

, Alyaev

, et al. [Comparative analysis of the effectiveness of various techniques of endoscopic prostate enucleation in a single center]. Khirurgiia (Mosk), 2017:11; 4–14.

22.

Misraï

, Pasquie

, Bordier

, Elman

, Lhez

, Guillotreau

, Zorn

. Comparison between open simple prostatectomy and green laser enucleation of the prostate for treating large benign prostatic hyperplasia: A single-centre experience. World J Urol, 2018; 36:793–799.

23.

Parsons

, Rangarajan

, Palazzi

, Chang

. A national, comparative analysis of perioperative outcomes of open and minimally invasive simple prostatectomy. J Endourol, 2015; 29:919–924.

24.

Barie

, Eachempati

. Surgical site infections. Surg Clin North Am, 2005; 85:1115–1135, viii–ix.

25.

Bass

3rd , Jarvis

JAW

, Mitchell

CK.

Urinary tract infections. Prim Care, 2003; 30:41–61, v–vi.

26.

Ketan

, Prashant

. Thulium laser enucleation of the prostate is a safe and a highly effective modality for the treatment of benign prostatic hyperplasia—Our experience of 236 patients. Urol Ann, 2016; 8:76–80.

27.

Ahyai

, Chun

FKH

, Lehrich

, Dahlem

, Zacharias

, Fisch

, Kuntz

. Transurethral holmium laser enucleation versus transurethral resection of the prostate and simple open prostatectomy—Which procedure is faster?. J Urol, 2012; 187:1608–1613.

28.

Bach

, Huck

, Wezel

, Hacker

, Gross

, Michel

. 70 vs 120 W thulium:yttrium-aluminium-garnet 2 microm continuous-wave laser for the treatment of benign prostatic hyperplasia: A systematic ex-vivo evaluation. BJU Int, 2010; 106:368–372.

29.

Netsch

, Bach

, Herrmann

TRW

, Neubauer

, Gross

. Evaluation of the learning curve for Thulium VapoEnucleation of the prostate (ThuVEP) using a mentor-based approach. World J Urol, 2013; 31:1231–1238.

30.

Teichmann

H-O

, Herrmann

, Bach

. Technical aspects of lasers in urology. World J Urol, 2007; 25:221–225.

31.

Wei

, Zhuo

, Sun

, et al. Safety and efficiency of thulium laser prostate resection for the treatment of benign prostatic hyperplasia in large prostates. Lasers Med Sci, 2014; 29:957–963.

32.

Jacques

. Optical properties of biological tissues: A review. Phys Med Biol, 2013; 58:R37–R61.