Efficacy and Safety of 1470 nm Diode Laser Enucleation of the Prostate in Elderly Benign Prostatic Hyperplasia Patients

Abstract

Objective:

The aim of this study was to evaluate efficacy and safety of 1470 nm diode laser enucleation of the prostate (DiLEP) and plasmakinetic resection of the prostate (PKRP) in elderly benign prostatic hyperplasia (BPH) patients with lower urinary tract symptoms.

Methods:

A total of 123 elderly patients with BPH were randomized to undergo either 1470 nm DiLEP or PKRP by means of a random number table from September 2020 to April 2022. The perioperative and postoperative data were studied during a 3- and 6-month follow-up.

Results:

The patients treated with 1470 nm DiLEP had significantly decreased operation time (74.6 ± 17.0 vs 98.8 ± 18.9 minutes, p < 0.001), hemoglobin loss (1.06 ± 0.49 vs 1.59 ± 0.60 g/dL, p < 0.001), bladder irrigation time (22.1 ± 8.1 vs 33.9 ± 10.0 hours, p < 0.001), catheter duration (3.2 ± 1.3 vs 5.8 ± 1.0 days, p < 0.001), and hospital stay (7.6 ± 1.4 vs 9.6 ± 1.3 days, p < 0.001) compared with the PKRP group. Besides, International Index of Erectile Function-5 score of 1470 nm DiLEP group at postoperative 3- and 6-month follow-up was significantly higher than PKRP group. No differences achieving statistical significance were identified in total prostate-specific antigen, maximum urinary flow rate, International Prostate Symptom Score, quality-of-life score, and the postvoid residual urine volume, transient incontinence, urethral stricture, bladder neck contracture, and retrograde ejaculation at 3- and 6-month follow-up.

Conclusions:

1470 nm DiLEP is safer than PKRP, with a smaller effect on sexual function, and it is comparable with the efficacy of PKRP, thus making it more suitable for elderly BPH patients.

Clinical Trial Registration number: S2021-463-01.

Introduction

Benign prostatic hyperplasia (BPH) refers to the main cause of lower urinary tract symptoms (LUTS) in aging men, seriously affecting their quality of life (QoL).¹ The incidence of BPH is positively correlated with age, ranging from 40% in men aged >50 years to 90% in men aged >80 years.² With the global escalation of the aging process, the number of elderly BPH patients (BPH patients >70 years of age) requiring surgical treatment is increasing.³ Transurethral resection of the prostate (TURP) is still the gold standard management of BPH for decades,⁴ whereas there are some complications that should be concerned after TURP.⁵ Besides, TURP shows numerous disadvantages for elderly BPH patients.

To be specific, elderly BPH patients often have chronic underlying disease, thus causing increased surgical and anesthetic risks.^6,7 Moreover, longer operative time and more bleeding are caused because of the larger prostate size in elderly BPH patients.⁸ Sexual function of elderly BPH patients (e.g., erectile function) is more likely to be impaired.⁹ Thus, the surgical outcome is worse and the perioperative and postoperative complications are higher in elderly BPH patients. Accordingly, it is imperative to find a safer and more effective minimally invasive procedure than TURP for the treatment of elderly BPH patients.

To improve the aforementioned issues, many urologists have explored new surgical treatment options to BPH.¹⁰ In recent years, enucleation of the prostate has been performed in more centers.¹¹ In comparison with TURP, it is safer with thorough removal of prostate tissue and less bleeding.¹² Our previous studies found that plasmakinetic vapor enucleation of the prostate with button electrode had advantages in terms of efficacy and safety compared with plasmakinetic resection of the prostate (PKRP) in large volume prostate patients.¹³ As new equipment continues to emerge, lasers have been used more often for enucleation of the prostate (e.g., holmium laser, green laser, thulium laser, and diode laser).^14

–17 In particular, the diode laser, which can be absorbed by water and hemoglobin at a wavelength of 1470 nm, reducing the damage to the surrounding prostate tissue and providing a high degree of safety.¹⁸

Based on the aforementioned, a prospective randomized study comparing the efficacy and safety of 1470 nm diode laser enucleation of the prostate (DiLEP) with PKRP in elderly patients with BPH was carried out in our research.

Materials and Methods

Patients

A total of 123 elderly patients with BPH were included in this study from September 2020 to April 2022. These patients were randomized to undergo either 1470 nm DiLEP or PKRP by means of a random number table. In general, the number of patients in the 1470 nm DiLEP group and the PKRP group was 61 and 62. The exclusion criteria were as follows: age <70, bladder cancer, prostate cancer, neurogenic bladder, urethral stricture, as well as a history of prostatic or urethral surgery. This study was authorized by the Ethics Committee of our hospital. The informed consent was received from the patients before the operation. Finally, 120 elderly patients with BPH (1470 nm DiLEP 60 vs PKRP 60) who completed the full follow-up were enrolled in our research (Fig. 1).

FIG. 1.

Patient flowchart. DiLEP = diode laser enucleation of the prostate; PKRP = plasmakinetic resection of the prostate.

All elderly patients with BPH were estimated preoperatively by the prostate volume (transabdominal ultrasound measured), the postvoid residual urine volume (PVR, transabdominal ultrasound measured), International Prostate Symptom Score (IPSS), maximum urinary flow rate (Qmax), QoL score, total prostate-specific antigen (tPSA), as well as International Index of Erectile Function-5 (IIEF-5). The perioperative data included hemoglobin loss, sodium decrease, operation time, catheter duration, and hospital stay.

Surgical procedures

Both procedures were performed by the same senior surgeon experienced in both 1470 nm DiLEP and PKRP. The patients who underwent procedures were administered epidural anesthesia or general anesthesia in a lithotomy position. 20F three-way Foley catheter was inserted into the bladder, and physiologic saline was employed for continual irrigation in these procedures.

The procedure of 1470 nm DiLEP

The 1470 nm DiLEP procedure was performed by the 1470 nm diode laser therapy system (ML-DD01F, QiZhi, WuHan) based on a 26F continuous resectoscope and morcellator system (YSB-III, Hawk, HangZhou), which was operated with a vaporization power of 150 W and a coagulation power of 30 W. The detailed surgical techniques have been elucidated previously.¹⁵ In brief, the position of external sphincter was observed, the reversing “U” incision was made at the proximal verumontanum first, other incisions were made from proximal verumontanum to the bladder neck at 5 o'clock and 7 o'clock positions with the urethral mucosa cut to surgical capsule's level.

The middle lobe was enucleated after the aforementioned procedures. Next, a retrograde incision was made from 0.5 cm of the proximal external sphincter to the bladder neck at 12 o'clock positions. The enucleation of right and left lateral lobes was from 5 o'clock and 7 o'clock positions to 12 o'clock clockwise or counterclockwise. The prostate tissue in the bladder was removed using the morcellator system.

The procedure of PKRP

The PKRP procedure was performed by the Olympus Plasmakinetic System, which was set to 280 W for cutting and 120 W for coagulation. The detailed procedure techniques have been described in our previous study.¹³ In short, the resectoscope was passed into the bladder under direct vision and the anatomical landmarks such as the verumontanum, bladder neck, and bilateral ureteral orifices were confirmed. The verumontanum was used as a distal landmark, the marker sulcus was first incised at the 6 o'clock position of bladder neck to the level of the surgical capsule. Then, the median lobe and lateral lobes of prostate glands were sequentially resected.

Three- and six-month follow-up

Follow-up was conducted at 3 and 6 postoperative months. PVR, Qmax, IPSS, QoL, tPSA, and IIEF-5 were evaluated at respective follow-up. Postoperative complications were also recorded (e.g., retrograde ejaculation, transient incontinence, urethral stricture, and bladder neck contracture).

Statistical analysis

All data were statistically analyzed by SPSS 26.0. The measurement data were expressed as mean ± standard deviation (SD) ( $\bar{x}$ ± SD), and t-test was used for the comparison between two groups. The enumeration data such as the postoperative adverse events were expressed as frequencies and percentages [n (%)] and treated with the chi-square test. P < 0.05 indicated statistically significant differences.

Results

There was no difference with statistical significance in any baseline data of patients between two groups (Table 1). The aforementioned parameters included age, prostate volume, tPSA level, PVR, Qmax, IPSS, as well as QoL. Table 1 lists the significant differences in the operation time, hemoglobin loss, catheter duration, and hospital stay, which favors 1470 nm DiLEP outperform PKRP in the aforementioned parameters.

Table 1.

Baseline Patient Characteristics and Perioperative Data

Parameters	1470 nm DiLEP	PKRP	p
Age, years	77.6 ± 3.6	77.3 ± 3.2	0.705
Prostate volume, mL	71.8 ± 23.0	71.5 ± 24.1	0.940
tPSA, ng/mL	2.58 ± 0.91	2.53 ± 0.97	0.784
PVR, mL	221.5 ± 80.1	217.5 ± 83.1	0.791
Qmax, mL/s	6.5 ± 1.3	6.5 ± 1.4	0.979
IPSS	25.3 ± 3.0	25.1 ± 2.5	0.718
QoL	4.9 ± 0.8	4.9 ± 0.8	0.733
Operation time, minutes	74.6 ± 17.0	98.8 ± 18.9	<0.001
Hemoglobin loss, g/dL	1.06 ± 0.49	1.59 ± 0.60	<0.001
Sodium decrease, mmol/L	2.57 ± 0.97	2.59 ± 1.13	0.914
Bladder irrigation time, hours	22.1 ± 8.1	33.9 ± 10.0	<0.001
Catheter duration, days	3.2 ± 1.3	5.8 ± 1.0	<0.001
Hospital stay, days	7.6 ± 1.4	9.6 ± 1.3	<0.001

Two-sample t-test for independent samples (p < 0.05 was considered statistically significant).

DiLEP = diode laser enucleation of the prostate; IPSS = International Prostate Symptom Score; PKRP = plasmakinetic resection of the prostate; PVR = postvoid residual urine volume; Qmax = maximum urinary flow rate; QoL = quality of life; tPSA = total prostate-specific antigen.

Three- and 6-month follow-up data are listed in Tables 2 and 3. Table 2 lists the postoperative data (including Qmax, PVR, IPSS, QoL, and tPSA). At 3 and 6 months, PVR, IPSS, QoL, and tPSA all significantly decreased compared with the perioperative data in the respective group, but Qmax was significantly improved. No difference with statistical significance was found between two groups at 3 and 6 months.

Table 2.

Baseline and 3- and 6-Month Follow-Up Data

	Baseline	3 Months	6 Months
tPSA
1470 nm DiLEP	2.58 ± 0.91	1.88 ± 0.63	1.55 ± 0.45
PKRP	2.53 ± 0.97	1.90 ± 0.63	1.50 ± 0.48
p-Value	0.784	0.842	0.600
PVR
1470 nm DiLEP	221.5 ± 80.1	22.0 ± 6.4	18.6 ± 6.8
PKRP	217.5 ± 83.1	22.3 ± 8.6	18.2 ± 6.3
p-Value	0.791	0.810	0.707
Qmax
1470 nm DiLEP	6.5 ± 1.3	21.1 ± 2.8	23.8 ± 2.4
PKRP	6.5 ± 1.4	20.8 ± 2.5	23.6 ± 3.0
p-Value	0.979	0.456	0.711
IPSS
1470 nm DiLEP	25.3 ± 3.0	8.4 ± 2.8	7.3 ± 2.3
PKRP	25.1 ± 2.5	8.2 ± 2.4	7.4 ± 2.1
p-Value	0.718	0.778	0.772
QoL
1470 nm DiLEP	4.9 ± 0.8	2.0 ± 0.7	1.8 ± 0.7
PKRP	4.9 ± 0.8	2.1 ± 0.8	1.7 ± 0.6
p-Value	0.733	0.350	0.561

Two-sample t-test for independent samples (p < 0.05 was considered statistically significant).

Table 3.

Baseline and 3- and 6-Month Follow-Up Sexual Function Data

	Baseline	3 Months	6 Months
IIEF-5
1470 nm DiLEP	18.4 ± 4.6	18.6 ± 4.3	18.7 ± 4.1
PKRP	18.5 ± 4.0	17.0 ± 4.4	17.1 ± 4.3
p-Value	0.899^*	0.047^*	0.035^*
Retrograde ejaculation, n (%)
1470 nm DiLEP	0	3 (5)	2 (3.3)
PKRP	0	8 (13.3)	7 (11.7)
p-Value	—	0.114^†	0.083^†

Two-sample t-test for independent samples (p < 0.05 was considered statistically significant).

†

Chi-square test (p < 0.05 was considered statistically significant).

IIEF-5 = International Index of Erectile Function-5.

The preoperative, 3 and 6 months postoperative IIEF-5 scores and the number of retrograde ejaculations in the two groups are listed in Table 3. There was no difference with significance in the preoperative IIEF-5 scores between the two groups (18.4 ± 4.6 and 18.5 ± 4.0, respectively; p = 0.899). There were significant differences in the IIEF-5 scores at 3 and 6 months after surgery in respective group (p = 0.047, p = 0.035). Three and two patients in the 1470 nm DiLEP group, and eight and seven patients in the PKRP group developed retrograde ejaculation at 3 and 6 months, whereas no statistical differences were found between the respective group (p = 0.114, p = 0.083).

During the postoperative follow-up period, three and two patients in the 1470 nm DiLEP group, and six and four patients in the PKRP group suffered from varying degrees of transient incontinence at the 3- and 6-month follow-ups without intrinsic sphincter deficiency through urodynamic evaluation. No significant difference was identified between the two groups (p = 0.298, p = 0.402). The number of urethral strictures was two in the 1470 nm DiLEP group, whereas there were five cases in the PKRP group. No significant difference was identified between the respective group (p = 0.243) (Table 4). Two patients in the 1470 nm DiLEP group had bladder neck contracture, five cases occurred in the PKRP group, but no statistical differences were found between the two groups of patients who underwent the different procedures (p = 0.402).

Table 4.

Perioperative Complications

	3 Months	6 Months
Transient incontinence, n (%)
1470 nm DiLEP	3 (5)	2 (3.3)
PKRP	6 (10)	4 (6.7)
p-Value	0.298	0.402
Urethral stricture, n (%)
1470 nm DiLEP	2 (3.3)	2 (3.3)
PKRP	5 (8.3)	5 (8.3)
p-Value	0.243	0.243
Bladder neck contracture, n (%)
1470 nm DiLEP	2 (3.3)	2 (3.3)
PKRP	4 (6.7)	4 (6.7)
p-Value	0.402	0.402

Chi-square test (p < 0.05 was considered statistically significant).

Discussion

This study indicated the better safety and equal efficacy of 1470 nm DiLEP compared with PKRP in elderly BPH patients with good surgical effects and less complications.

In this study, 1470 nm DiLEP was safer than PKRP. The reasons for this result are presented as follows. 1470 nm DiLEP was effective in enucleating the prostate tissue, this characteristic can shorten the anesthesia and operative time significantly and reduce the surgical risk, which benefits elderly patients with underlying diseases such as cardiopulmonary insufficiency. Besides, there was less hemoglobin loss in the 1470 nm DiLEP group. The reason for this is that 1470 nm DiLEP showed excellent coagulation and vaporization characteristic and enucleation started from the surgical capsule, which can avoid repeated hemostasis.¹⁹

In contrast, the same vessel is repeatedly bleeding and coagulated to stop the bleeding at different levels, thus causing hemoglobin loss during PKRP. Besides, patients treated by 1470 nm DiLEP can be administrated with oral anticoagulants or antiplatelet drugs continuously,²⁰ so there is a small effect on pre-existing cardio-cerebrovascular disease and a lower risk of cardio-cerebrovascular accidents during the perioperative period.

1470 nm DiLEP indicated a smaller effect on sexual function compared with PKRP (e.g., erectile function and ejaculation function). The erectile dysfunction after prostate surgery is mainly associated with perforation of the capsule and erection-related vascular and nerve damage during operation.²¹ The unavoidable use of electrocoagulation or electrotomy during PKRP causes long operating time, tissue bleeding, thermal injury, capsule perforation, and inflammation, which inevitably increases the chance of damage to the erectile nerve and vascular bundle outside the prostate capsule, thus more significantly affecting erectile function.

However, surgical capsule can be found clearly during 1470 nm DiLEP, which can avoid the harm and perforation of the capsule and decrease the chance of exudation and inflammation. Besides, erection-related vascular and nerve damage can be decreased as a result of shallower heat injury during 1470 nm DiLEP than PKRP.^22
–24 In comparison with PKRP, DiLEP can preserve the internal sphincter of the bladder neck and maintaining the integrity of the bladder neck, which can reduce the occurrence of retrograde ejaculation.²⁵

1470 nm DiLEP and PKRP had the similar efficacy for remission obstruction and LUTS. PVR, Qmax, IPSS, QoL, and tPSA were all significantly ameliorated after 1470 nm DiLEP. Compared with PKRP, DiLEP has decreased bladder irrigation time, catheter duration, and hospital stay as previous report.²⁶ The possible reason for the aforementioned result is the wavelength of the diode laser providing the highest simultaneous absorption both in water and hemoglobin, thus leading to good hemostasis a clear vision field to the surgeons.²⁷ For complications, transient incontinence, urethral stricture, and bladder neck contracture were explored in this study. In comparison with PKRP, the number of the aforementioned cases was fewer in 1470 nm DiLEP, whereas no difference with statistical significance was identified between groups at 3 and 6 months. The aforementioned result may be correlated with the limited number of cases in the enrolled sample.

Because of the limitations of this trial, such as the single-center experience and short follow-up, the current research conclusions require further validation through multicenter large-sample studies and long-term follow-up data.

Conclusion

Compared with PKRP, better safety and equal efficacy of 1470 nm DiLEP were achieved with less bleeding, significantly shorter operation time, bladder irrigation time, duration of catheter and hospital stay, and especially a smaller effect on sexual function, thus making it more suitable for elderly patients with BPH.

Footnotes

Authors' Contributions

D.S. collected data and drafted the article. Z.Z. and Z.L. were responsible for screening the patients for the study. H.Z., D.S., T.D., and Z.W. evaluated patients and recorded data. K.Z. and Q.F. conceived the study, participated in its design, and gave final approval of the version to be published. All authors read and approved the final article.

Author Disclosure Statement

There are no conflicts of interest declared by the authors.

Funding Information

This research was supported by The National Key Research and Development Program of China (2021YFC2009300 and 2021YFC2009304), Academic Promotion Programme by Shandong First Medical University (2020LI001).

Abbreviations Used

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