A Prospective Study on the Effect of Photoselective Vaporization of Prostate by 120-W High-Performance System Laser on Sexual Function

Abstract

Introduction:

Photoselective vaporization of prostate (PVP) by 120W HPS laser emerged as an efficient, bloodless, and durable first line alternative to transurethral resection of prostate for treatment of lower urinary tract symptoms (LUTS) secondary to benign prostatic enlargement (BPE). In this study, we assessed effects of PVP by HPS laser on erectile function.

Material and Methods:

Between January 2012 and February 2014, 143 consecutive patients presenting with LUTS secondary to BPE, who underwent PVP by 120W HPS laser, were prospectively enrolled in the study. Patient's (Group A: International Index of Erectile Function-5 (IIEF-5) ≥19; Group B: IIEF <19) preoperative, perioperative and follow-up data were recorded. IIEF-5 was used to assess preoperative and postoperative erectile function at 1, 3, 6, and 12 months. Recorded data was analyzed statistically.

Results:

Preoperative and perioperative data of the two groups were comparable. Significant improvement in IPSS, Qmax, QoL, and post void residual urine at 1, 3, 6 and 12 months were observed in both groups with no significant difference between them. Although IIEF-5 scores declined in both groups postoperatively (Group A: 21.06±1.21 to 19.84±1.55, P=0.43; Group B: 14.67±2.05 to 12.79±1.42, P=0.53), it was not statistically significant in either group. No significant difference was noted in IIEF-5 score between patients with or without indwelling catheter in either of the two groups.

Conclusions:

In patients undergoing PVP by 120W HPS laser for LUTS secondary to BPE, no significant effect was observed in sexual function at 1 year follow-up.

Introduction

In recent years, photoselective vaporization of prostate (PVP) has emerged as an efficient, bloodless, and durable first line alternative to transurethral resection of prostate (TURP) for the surgical treatment of lower urinary tract symptoms (LUTS) secondary to benign prostatic enlargement (BPE).^1,2 Although significant improvement is reported in urinary symptoms with PVP by 120-W high-performance system laser (HPS laser), little is reported in the literature about the impact on sexual function.^3,4 Direct thermal injury to the erectile nerves is the possible cause of PVP–induced erectile dysfunction (ED).⁵ Since introduction in 2006, the lithium triborate (LBO) laser, also known as the GreenLight^™ HPS laser, has gradually replaced the 80-W potassium titanyl phosphate (KTP) laser. Due to its more collimated laser beam, this laser allows more efficient tissue vaporization.⁶ Despite the higher energy associated with HPS laser use and the theoretical risk of damage to erectile nerves, some studies demonstrated no detrimental effect on sexual function.^6,7 Now it is known that urinary symptoms influence the sexual function of men with LUTS, and further research has been recommended to evaluate the sexual consequences of new surgical options for LUTS secondary to BPE.⁸

Few prospective studies have been published regarding the effect of the 120-W HPS laser on sexual function.^5
–7 Therefore, we have conducted this study to assess the effect of PVP by 120-W HPS laser on sexual function in patients presenting with LUTS secondary to BPE. This is the first reported series from Southeast Asia evaluating the effect of this laser on sexual function.

Material and Methods

We conducted a prospective, nonrandomized comparative study between April 2011 and December 2013.

Inclusion criteria and patient evaluation

We included consecutive patients presenting with LUTS secondary to BPE scheduled for PVP by 120-W HPS laser. Patients were not included if they had a history of carcinoma prostate, neurogenic bladder disease, urethral stricture, uncontrolled diabetes with HbA1c levels ≥7 mg/dL, a major psychiatric disorder, history of urethral or prostatic surgery, were receiving a 5α-reductase inhibitor or phosphodiesterase-5 (PDE5) inhibitor, did not complete the International Index of Erectile Function (IIEF-5) score sheet, or didn't give informed consent.

Patient evaluation included the following: a detailed clinical history, including age and international prostate symptom score (IPSS), IIEF-5, and quality of life (QOL) scores; examination of external genitalia; digital rectal and focused neurologic examinations; other investigations, such as urinalysis, hemoglobin, serum prostate-specific antigen (PSA), prostate volume measurement by transrectal ultrasound (TRUS), postvoid residual urine (PVRU) estimation by abdominal ultrasound, and Q_max on uroflowmetry. Prostate cancer was ruled out by 12-core TRUS-guided prostatic biopsy in patients with abnormal digital rectal examination and/or PSA levels >4 ng/mL. Patients were divided into two groups based on preoperative IIEF-5 scores: group A had IIEF-5 scores ≥19 (A1=no preoperative indwelling catheter, A2=preoperative indwelling catheter) and group B had IIEF-5 scores <19 (B1=no preoperative indwelling catheter, B2=preoperative indwelling catheter).

Surgical procedure

All procedures were performed by one of the two consultants of our department. All surgeries were done under spinal anesthesia with the exception of patients on anticoagulant therapy, for whom general anesthesia was used. A 23F continuous flow laserscope, a 30 degree lens, a 600 micron, 70 degree side-firing HPS laser fiber with a wavelength of 532nm, and 0.9% sodium chloride for irrigation were used. Vaporization of prostatic tissue was done up to surgical capsule with the aim of achieving a wide TURP-like cavity. The distal limit of vaporization was the proximal end of verumontanum. The power setting was changed from 120-W to 80-W for vaporization of a 1 cm length of prostate adjacent to verumontanum.

In all patients, a 20F three-way Foley catheter was kept in situ after the procedure. Irrigation with 0.9% normal saline, if required, was started after the procedure till urine was clear. The catheter was removed in all patients the morning after surgery. Those who failed to void were recatheterized and given a voiding trial after 5 days. As per institutional policy, each patient was given a single dose of preoperative intravenous antibiotic at induction and an oral antibiotic for 5 days post catheter removal.

Recorded perioperative parameters included total energy used, energy used near prostatic apex (1 cm length of prostate just proximal to verumontanum), duration of operation (period for which laserscope was in situ), and duration of catheterization. Patients were followed up at 1, 3, 6, and 12 months, and IPSS, Q_max, PVRU, QOL, and IIEF-5 score parameters were recorded.

Statistical analysis

The primary outcome measure for analysis was the IIEF-5 score, while the secondary outcome measures for analysis were IPSS, Q_max, PVRU, and QOL scores. Recorded parameters were arranged using Microsoft Excel spreadsheets and analyzed by the SPSS version 12.0 software package. The parametric outcomes were expressed as the mean±standard deviation (SD) of the group. A two-tailed Student t-test was used as a statistical tool for continuous variables. χ ²-test and Fisher exact test were used to analyze categorical data. P values <0.05 were considered statistically significant.

Results

Of 154 patients screened, 70 and 84 patients were categorized in group A and B respectively. Subsequently 3 and 8 patients, from groups A and B respectively, were excluded from the study. This left 67 and 76 patients in groups A and B for analysis. See Figure 1 for the allocation of patients in this study.

FIG. 1.

Allocation and dispersion of patients.

Table 1 summarizes the baseline characteristics of the two groups. None of the baseline parameters were significantly different between the two groups; these parameters include patients age, PSA levels, prostate volume, IPSS, Q_max, PVRU, QOL, number of patients on anticoagulant, and number of patients on indwelling catheter.

Table 1.

Preoperative Data

	Group A	Group B	P value
Number of patients	67	76	0.43 (NS)
Age (years)	61.04±4.86	62.48±5.91	0.12 (NS)
PSA (ng/mL) (mean±SD)	2.85±1.99	3.30±2.69	0.11 (NS)
Indwelling catheter (%)	33 (49.25)	37 (48.68)	0.35 (NS)
Anticoagulant (%)	23 (34.32)	28 (36.84)	0.67 (NS)
Median prostate volume in mL (range)	70.60±27.32	68.25±22.53	0.42 (NS)
Mean IPSS (mean±SD)	20.16±3.10^*	20.34±1.87^#	0.17 (NS)
Mean Q_max (mL/min) (mean±SD)	6.52±1.96^*	7.71±1.72^#	0.27 (NS)
Mean PVRU (mL) (mean±SD)	129.40±49.50^*	154.78±48.79^#	0.31 (NS)
Mean QOL (mean±SD)	3.92±1.08	3.83±1.17	0.16 (NS)

n=34.

n=39.

Group A, IIEF-5 ≥19; Group B, IIEF-5 <19.

IPSS=international prostate symptom score; PVRU=postvoid residual urine; PSA=prostate-specific antigen; QOL=quality of life; SD=standard deviation.

The perioperative data is summarized in Table 2. The total amount of energy used, energy used near prostatic apex, duration of operation, and duration of catheterization were not significantly different between the two groups. The follow-up data was recorded in Table 3. Patients of both groups (A and B) demonstrated significant improvement in mean IPSS score, Q_max, PVRU, and QOL score at 1 month follow-up, and the improvement was consistent at 12 months follow-up. These parameters were not significantly different between the two groups during follow-up.

Table 2.

Perioperative Data

	Group A	Group B	P value
Total energy used (KJ)	180.72±33.53	182.85±30.65	0.24 (NS)
Energy used near apex (KJ)	16.14±3.97	16.95±3.79	0.26 (NS)
Duration of operation (min)	72.52±44.22	68.10±16.22	0.31 (NS)
Duration of catheterization (h)	24.21±3.24	23.22±4.08	0.53 (NS)

Values are shown in mean±standard deviation.

Group A, IIEF-5≥19; Group B, IIEF-5<19.

Table 3.

Follow-Up Data

	Preoperative		1 month postoperative		3 months postoperative		6 months postoperative		12 months postoperative
	A (n=67)	B (n=76)	A (n=67)	B (n=76)	A (n=66)	B (n=75)	A (n=65)	B (n=75)	A (n=63)	B (n=72)	P value
Mean IPSS	20.16±3.10	20.34±1.87	9.55±1.33	10±1.30	7.47±1.04	7.42±1.35	7.19±1.12	6.96±1.45	7.17±1.13	7±1.45	0.01 (S)
Mean Q_max	6.52±1.96	7.71±1.72	18.86±6.63	18.03±5.75	18.80±6.45	18.24±5.56	19.20±6.00	18.64±5.46	19.48±5.82	18.67±5.45	0.02 (S)
Mean PVRU (mL)	129.40±49.50	154.78±48.79	60.72±16.77	44.90±14.30	36.19±12.34	37.24±11.44	34.36±16.49	30.89±12.84	34.35±16.67	32.20±12.82	0.01 (S)
Mean QOL	3.92±1.08	3.83±1.17	1.95±0.69	2.11±0.61	1.45±0.50	1.81±0.56	1.43±0.50	1.66±0.57	1.44±0.50	1.76±0.48	0.03 (S)

Values are shown in mean±standard deviation.

Group A, IIEF-5≥19; Group B, IIEF-5<19.

IPSS=international prostate symptom score; PVRU=postvoid residual urine; QOL=quality of life.

Table 4 summarizes the preoperative and follow-up mean IIEF-5 scores. The mean preoperative IIEF-5 scores in group A and B are 21.06±1.21 and 14.67±2.05, respectively. In group A patients, the mean IIEF-5 score decreased at 1, 3, 6, and 12 month follow-up, but the decrease was not significant (P=0.43). Decline in mean IIEF-5 score was also observed in group B patients at 1, 3, 6, and 12 month follow-up, and it was not significant (P=0.53). IIEF-5 data of patients with and without indwelling catheters in either group is summarized in Table 5. Subgroup analysis in both groups (A1 vs A2; B1 vs B2) did not show significant difference in IIEF-5 data of patients with and without indwelling catheters.

Table 4.

IIEF-5 Data

	Preoperative (67/76)	1 month postoperative (67/76)	3 months postoperative (66/75)	6 months postoperative (65/75)	12 months postoperative (63/72)	P value
Group A (n=48)	21.0 6±1.21	20.29±1.41	20.06±1.52	19.95±1.50	19.84±1.55	0.43 (NS)
Group B (n=76)	14.67±2.05	13.65±1.70	13.08±1.50	12.97±1.51	12.79±1.42	0.53 (NS)

Values are shown in mean±standard deviation.

Group A, IIEF-5≥19; Group B, IIEF-5<19.

Table 5.

IIEF-5 Subgroup Data

	A1 (n=34)	A2 (n=33)	P value	B1 (n=39)	B2 (37)	P value
Preoperative	21.20±1.08	20.91±1.34	0.41	14.73±1.99	14.61±2.12	0.80
1 month postoperative	20.20±1.58	20.39±1.23	0.66	13.64±1.55	13.66±1.84	0.96
3 months postoperative	20.08±1.75	20.04±1.29	0.92	12.81±1.44	13.28±1.53	0.18
6 months postoperative	20.04±1.74	19.86±1.25	0.69	12.81±1.44	13.09±1.57	0.43
12 months postoperative	20.00±1.87	19.69±1.18	0.51	12.59±1.29	12.95±1.51	0.29

Values are shown in mean±standard deviation.

A1=no preoperative indwelling catheter (IIEF-5≥19); A2=preoperative indwelling catheter (IIEF-5≥19).

B1=no preoperative indwelling catheter (IIEF-5<19); B2=preoperative indwelling catheter (IIEF-5<19).

Discussion

Strong strength of association and dose response effects between ED and LUTS is a proven fact. Also, urinary symptoms are known to affect sexual function in men with LUTS.^8,9 For evaluating the sexual function in men with LUTS secondary to BPE, IIEF-5 is an accepted and effective diagnostic questionaire.^10,11

Various authors reported the effect of surgical treatment of BPE on sexual function. TURP is considered a safe procedure for preservation of sexual function. Risk factors associated with detrimental effect on sexual function are diabetes mellitus, severe cardiovascular disease, small adenoma, and capsular perforation.^12

–15 Jaidane et al found improvement in sexual function even in cases of capsular perforation during TURP.¹⁶ Currently, commonly used lasers for BPE surgery are the KTP/LBO laser, Holmium laser, and Thulium laser with wavelengths of 532 nm, 2,140 nm, and 2,013 nm, respectively, and corresponding 800 μm, 400 μm, and 250 μm depth of penetration in tissue.¹⁷ Theoretically, with the maximum depth of penetration, KTP/LBO laser has the maximum chance of damaging the erectile nerves. Thulium laser has been shown to improve sexual function, with large adenoma size being an adverse factor. Overall, a 20% risk of erectile dysfunction has been reported with Thulium laser.^18,19 As far as Holmium laser for BPE surgery is concerned, it has shown improvement in erectile function with results equivalent to TURP.^20,21

Few studies have reported the effect of PVP on sexual function. Paick and colleagues studied erectile function following high-power KTP laser PVP and observed significant improvement in total IIEF sum from a baseline mean of 27.4±3.8 to 34.9±3.7 (P=0.010). All IIEF domains demonstrated improvement at 6-month follow-up (P<0.05).²² Hamann et al observed no effect on erectile function and libido score with 80-W KTP laser.²³ Kavoussi and associates evaluated postoperative erectile function following PVP in a prospective study and observed that patients who were catheter free and those on CIC preoperatively maintained sexual function, whereas those with indwelling catheters showed improvement. They did not found significant differences between preoperative and postoperative sexual function for patients with mild or no preoperative erectile dysfunction.²⁴ In their prospective study, Bruyère et al used KTP laser for prostate <40 cm³ and LBO laser for prostate >40 cm³ and found comparable preoperative and postoperative IIEF-5 scores at 1-year follow-up. However, significant detrimental effect was seen at 24-month follow-up in patients with preoperative IIEF-5 scores >19. Effect on erectile function was not different with the 80-W KTP or 120-W LBO lasers. Diffusion of the power around the prostate, more at the apex than the base, may affect the erectile function.⁵ Hossack et al, with 120-W LBO laser, observed significant changes in erectile function (major decline in 12.4% and 24% and major improvement in 8.3% and 6% at 3 and 12 months, respectively).²⁵ Spaliviero et al prospectively evaluated sexual function following PVP by 120-W HPS laser and found no detrimental effect. Deterioration (Sexual Health Inventory for Men [SHIM] reduction >5) and improvement (SHIM increase >5) in erectile function was observed in 7% and 19.3% patients, respectively, at 52 weeks follow-up. New-onset retrograde ejaculation was found in 30%.⁶ Terrasa and associates prospectively analyzed 102 patients with 12-month follow-up and found no significant change in postoperative global DAN-PSSsex and erection symptom scores, but ejaculation symptom and DAN-PSSsex symptom scores were significantly worse (P=0.04). Significant improvement was found in postoperative DAN-PSSsex bother score (P<0.0001) and global sexual satisfaction (P=0.02), probably due to relief in urinary symptoms.⁷

In our study, which is the first reported study in Southeast Asian patients, improvements in IPSS, Q_max, PVRU, and QOL were significant at each follow-up. The mean IIEF-5 score decreased in both groups of patients, with the fall not statistically significant in either group (group A, 21.06±1.21 vs 19.84±1.55, P=0.43; group B, 14.67±2.05 vs 12.79±1.42, P=0.53). Although 33 (49.25%) and 37 (48.68%) of patients in group A and B respectively had preoperative indwelling catheters, subgroup comparative analysis among patients with and without indwelling catheters did not demonstrate significant difference between these groups (A1 vs A2; B1 vs B2). The result in group A patients (IIEF-5 ≥19) is in contrast with our previously published results using an 80-W KTP laser. With 80-W KTP laser use, patients with IIEF-5 ≥19 demonstrated significant decrease in IIEF-5 scores (21.1±2.1 vs 16.1±9.5, P=0.02).²⁶ The difference in results with 80-W and 120-W HPS lasers may be due to less total energy delivered at the prostatic apex. As the results for these two lasers are from different time periods, definite conclusions cannot be drawn. A future study measuring the effect of total energy delivered specifically at the apex may provide suitable answers.

Conclusion

In patients undergoing PVP by 120-W HPS laser for LUTS secondary to BPE, no significant effect was observed in sexual function at 1-year follow-up.

Footnotes

Disclosure Statement

No competing financial interests exist.

Abbreviations Used

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