Clinical Efficacy Study of Green Light Top-Firing Sharp for the Treatment of Short-Segment Urethral Strictures in Men

Abstract

To analyse and evaluate the safety and efficacy of green light top-firing sharp in the treatment of short-segment urethral stricture in men. A retrospective analysis of the medical records of 65 men with short-segment urethral strictures confirmed at our hospital over the past 5 years was conducted. Patients were divided into two groups based on the surgical procedure: the cold knife urethral stricture endotomy group (direct vision internal urethrotomy [DVIU] group, n = 33) and the green light top-firing sharp urethral stricture endotomy + urethral stricture scar vaporisation group (Photoselective vaporization of the prostate [PVP] group, n = 32). Data before and after surgery were collected. The operation time was shorter and intraoperative bleeding was less in the PVP group than in the DVIU group, and the difference between the two groups was significant. There was no significant difference in the incidence of postoperative complications between the two groups. There were significant differences in the maximum urinary flow rate, residual urine volume, International Prostate Symptom Score and quality of life score before and after surgery between the two groups. Green light top-firing sharp treatment of men’s short-segment urethral stricture involves less injury, less bleeding and less complications than cold knife urethral stricture dissection and is a safe and effective method.

Keywords

urethral stricture endoureterotomy direct-exit green laser vaporisation

Introduction

Urethral stricture is one of the common diseases in urology, with an incidence of around 0.3% to 2.0% in men (J. Liu et al., 2024). Clinical manifestations mainly include dysuria, narrowed urine stream and frequent/urgent urination. The primary therapies for urethral stricture include urethral dilation, internal urethrotomy, urethral stricture excision + end-to-end anastomosis and urethroplasty. Despite being a more conservative therapy, urethral dilation exhibits a high recurrence rate. Internal urethrotomy, as the preferred treatment option, is effective for strictures shorter than 2 cm but carries risks of surgical trauma, bleeding and postoperative stricture recurrence (J. Liu et al., 2024). There are various surgical methods for internal urethrotomy, including cold knife internal urethrotomy, electrosurgery and laser techniques, with laser cutting technologies such as holmium lasers and green light lasers (Endo et al., 2025).

Cold knife internal urethrotomy has long been considered the standard therapy for urethral strictures. The European Association of Urology guidelines recommend cold knife internal urethrotomy under direct vision for patients with strictures ≤2 cm, whereas internal urethrotomy should not be used alone for strictures ≥2 cm (Campos-Juanatey et al., 2021). While electrosurgery can remove urethral scar tissue, the high temperatures generated during the procedure can damage the urethra and periurethral tissues, potentially leading to recurrent urethral strictures. Despite the introduction of the plasma electrosurgery system by Gyrus in the United Kingdom, thermal injury to urethral tissue cannot be completely avoided (Basok et al., 2008; Cai et al., 2016).

In contrast, the laser internal urethrotomy technique boasts the advantages of satisfactory haemostatic effects, clear surgical field, a short learning curve and ease of use (Zhu et al., 2021) and has demonstrated clear efficacy in treating urethral strictures, with low recurrence rates and minimal damage. Specifically, lasers used for treating urethral strictures include a holmium laser, green light laser, 1,470 nm laser and thulium laser. A retrospective analysis of the medical records of patients with urethral strictures in our department over the past 5 years found that direct-output green light laser treatment for urethral stricture is both safer and more effective. The objective of this study is to assess the safety and efficacy of the direct-output green light laser method in treating short-segment urethral strictures in men while comparing it with traditional cold knife internal urethrotomy.

Materials and Methods

General Clinical Data

This is a retrospective study involving men diagnosed with short-segment urethral stricture at our hospital between 2018 and 2023. All included patients were men who underwent preoperative evaluation through retrograde and antegrade urethrography, urinary computed tomography (CT) and ureteroscopy, confirming the diagnosis of urethral stricture with a stricture ≤2 cm long. Based on the surgical approaches performed, patients were divided into two groups: the group with cold knife used for incision of urethral strictures (DVIU group) and the group with direct-output green light laser for incision of urethral strictures (PVP group). In the DVIU Group (n = 33, age: 25–78 years), based on the location of stenosis, there was bulbous stenosis (n = 13), membranous stenosis (n = 8), prostatic stenosis (n = 5) and bladder neck stenosis or atresia (n = 2). In the PVP group (n = 32, age: 26–80 years), based on the location of stenosis, there was bulbous stenosis (n = 17), membranous stenosis (n = 7), prostatic stenosis (n = 5) and bladder neck stenosis or atresia (n = 3). The inclusion criteria were as follows: (a) Men aged 18 years and above; (b) patients diagnosed with urethral stricture through retrograde and antegrade urethrography, urinary CT and ureteroscopy, with a stricture ≤2 cm long and (c) patients who consented to participate in the study and signed an informed consent form. The exclusion criteria included (a) patients with a stricture ≥2 cm long; (b) patients with severe cardiovascular diseases, diabetes or other underlying conditions; (c) patients with a history of urethral stricture surgery and (d) patients unable to comply with postoperative follow-up. This study was approved by the ethics committee of our hospital, the written informed consent was waived due to the retrospective nature of the study and the use of anonymised data in accordance with the Declaration of Helsinki and local regulatory requirements.

Surgical Methods

All procedures, including the green light laser surgeries, were performed by a single experienced surgeon. For the DVIUs (Ali et al., 2023), a Storz urethral stricture incision endoscope was inserted under direct vision to the site of the urethral stricture to observe the condition of the stricture and check for any associated false passages. Following this, a zebra guidewire or F4 ureteral catheter was placed into the bladder as a guide. Radial incisions were then made at the scar tissue of the urethral stricture using a cold knife, with incisions made at the 5 and 7 o’clock positions for the anterior urethra and at the 12, 3 and 9 o’clock positions for the posterior urethral stricture. Additionally, the scar tissue of the urethral stricture was adequately released, and the incision was advanced until it passed through the stricture segment and entered the bladder. Finally, an 18 to 22 F catheter was indwelled postoperatively and removed after 3 to 6 weeks.

In the PVP group (Atak et al., 2011), an electrosurgical resection endoscope was inserted under direct vision to the site of the urethral stricture to observe the condition of the stricture and check for any associated false passages. Following this, a zebra guidewire or F4 ureteral catheter was placed into the bladder as a guide. An inline green light laser fibre was then inserted through the operating channel, with power settings of 60 to 100 W for cutting and 40 W for coagulation, followed by radial incisions made at the scar tissue of the urethral stricture (i.e. incisions made at the 5 and 7 o’clock positions for the anterior urethra and at the 12, 3 and 9 o’clock positions for the posterior urethral stricture). After adequately releasing the scar tissue of the urethral stricture, the narrowed scar was vaporised and removed, with the incision advanced until it passed through the stricture segment and entered the bladder. Finally, an 18 to 22 F catheter was indwelled postoperatively and removed after 3 to 6 weeks.

Observation Indicators

The following observation indicators were recorded. (a) Surgical time and intraoperative blood loss. (b) Surgical complications (e.g. penile haematoma, penile oedema, urethral bleeding, bladder spasm, urinary incontinence, urinary retention and erectile dysfunction) (Litwin et al., 1998); (c) Residual urine volume (measured pre-operation and at 3, 6 and 9 months postoperatively): this refers to the remaining urine excreted from the bladder by catheterisation or other methods after normal urination, which is a key indicator for assessing voiding function. (d) Maximum urinary flow rate, the maximum urine flow rate recorded during urodynamic testing, generally expressed as millilitres per second (mL/s) and used for assessing urethral patency and voiding function. (e) International Prostate Symptom Score (IPSS), a scale used to assess the severity of prostate symptoms consisting of seven questions, with a score of 0 to 5 each and a total score of 0 to 35 (higher scores indicate more severe symptoms). (f) Quality of life (QoL) score, which is one of the questions in the IPSS questionnaire, assessing the impact of urinary symptoms on QoL, with scores of 0 to 6 (higher scores indicate a greater impact) (Barry et al., 1992).

Statistical Analysis

Statistical analysis of the collected data was performed using SPSS 22.0 software. Count data were expressed as mean ± standard deviation (x ± s), and t-tests or chi-square tests were utilised. Data not following the hypothesis of normal distribution were processed using non-parametric tests, such as the Mann–Whitney U test and Kruskal–Wallis H test. A p-value of <.05 was considered statistically significant.

Results

In the DVIU group, 33 patients received surgery, with 31 successfully operated on and 2 forced to terminate due to an unclear surgical field caused by significant surgical bleeding. In the PVP group, 32 patients received surgery, with all successfully operated. Significant differences were observed in the surgical time and intraoperative blood loss between the two groups, with the DVIU group reporting longer surgical time and more intraoperative blood loss than the PVP group (see Table 2). Baseline characteristics of patients in both groups are detailed in Table 1, including age, weight, comorbidities (e.g. hypertension, diabetes), length of stenosis, severity of stenosis, aetiology and the course of disease.

Table 1.

Baseline Characteristics of Patients

Characteristics	DVIU group (n = 33)	PVP group (n = 32)	p value
Age (years)	55.2 ± 10.5	54.6 ± 9.8	.7^a
Weight (kg)	72.3 ± 11.4	73.5 ± 12.1	.5^a
Comorbidities (n [%])
Hypertension	15 (45.5%)	14 (43.8%)	.9^b
Diabetes	8 (24.2%)	9 (28.1%)	.8^b
Length of stenosis (cm)	1.8 ± 0.3	1.7 ± 0.4	.3^b
Severity of stenosis (n [%])
Mild	10 (30.3%)	12 (37.5%)	.6^b
Moderate	15 (45.5%)	14 (43.8%)	.9^b
Severe	8 (24.2%)	6 (18.8%)	.7^b
Cause of disease (n [%])
Trauma	8 (24.2%)	7 (21.9%)	.9^b
Iatrogenic injury	15 (45.5%)	16 (50%)	.8^b
Inflammatory infection	10 (30.3%)	9 (28.1%)	.9^b
Course of disease (months)	24.5 ± 15.2	23.1 ± 14.6	.4^b

t-tests.

Chi-square tests.

Overall complications include penile haematoma, penile oedema, urethral bleeding, bladder spasm, urinary incontinence, urinary retention and penile erectile dysfunction. The overall incidence of complications was 6.45% (2/31) in the DVIU group and 24.2% (8/33) in the PVP group (p > .05), indicating no significant differences in surgical complications between the two groups (Table 2).

Table 2.

Inter-Group Comparison of Intraoperative Indicators and Surgical Complications

Items	DVIU (n = 31)	PVP (n = 33)	p value
Surgical time (min)	69.20 ± 19.40	24.20 ± 13.40	<.05^a *
Intraoperative blood loss (mL)	54.28 ± 19.86	21.40 ± 6.01	<.05^a *
Complications (n)
Penile haematoma	2	0	>.05^b
Penile oedema	1	0	>.05^b
Urethral haemorrhage	3	1	>.05^b
Rectal injury	0	0	>.05^b
Urinary retention	1	0	>.05^b
Urinary incontinence	0	0	>.05^b
Erectile dysfunction	2	0	>.05^b
Cost (Renminbi)	7,993.73 ± 833.11	13,001.34 ± 3,220.00	<.05^a *

t-tests

Chi-square tests.

p < .05.

Statistically significant differences were found in residual urine volume, maximum urinary flow rate, IPSS score and QoL score pre- and post-operation between the two groups, but there was no statistically significant difference in residual urine volume, maximum urinary flow rate, IPSS score and QoL score pre- and post-operation between the two groups (Tables 3–4).

Table 3.

Inter-Group Comparison of Residual Urine Volume and Maximum Urine Flow Rate

Items	DVIU (n = 31)	PVP (n = 33)	p value
Residual urine volume (mL)
Pre-operation	150 ± 60.09	152 ± 59.28	>.05^a
3 months post-operation	17.80 ± 7.70	17.02 ± 5.51	>.05^a
6 months post-operation	17.10 ± 7.00	16.23 ± 5.41	>.05^a
12 months post-operation	15.01 ± 5.23	14.90 ± 5.01	>.05^a
p value	<0.05^b *	<0.05^b *
Maximum urine flow rate (mL/s)
Pre-operation	4.47 ± 1.13	4.97 ± 1.37	>.05^a
3 months post-operation	18.90 ± 2.50	19.50 ± 2.71	>.05^a
6 months post-operation	17.14 ± 1.40	18.70 ± 1.35	>.05^a
12 months post-operation	18.50 ± 3.60	19.10 ± 3.10	>.05^a
p value	<.05^b *	<.05^b *

t-tests.

Mann–Whitney U test.

p < .05.

Table 4.

Inter-Group Comparison of IPSS Scores and QoL Scores

Items	DVIU (n = 31)	PVP (n = 33)	p value
IPSS scores
Pre-operation	25.50 ± 3.40	26.20 ± 2.15	>.05^a
3 months post-operation	9.41 ± 1.60	11.01 ± 1.70	>.05^a
6 months post-operation	9.15 ± 1.59	9.60 ± 2.20	>.05^a
12 months post-operation	9.20 ± 2.30	9.41 ± 1.85	>.05^a
p value	<0.05^b *	<0.05^b *
QoL scores
Pre-operation	4.50 ± 0.40	5.10 ± 0.41	>.05^a
3 months post-operation	1.20 ± 0.40	1.41 ± 0.51	>.05^a
6 months post-operation	1.30 ± 0.21	1.41 ± 0.20	>.05^a
12 months post-operation	1.10 ± 0.30	1.00 ± 0.30	>.05^a
p value	<.05^b *	<.05^b *

Note. QoL = quality of life.

t-tests.

Mann–Whitney U test.

p < .05.

Discussion

In this study, the direct-output green light laser internal urethrotomy for urethral stricture (PVP group) and cold knife internal urethrotomy for urethral stricture (DVIU group) methods for treating short-segment urethral stricture in men were compared in terms of safety and efficacy, thereby providing new clinical data. The findings showed shorter surgical time and less intraoperative blood loss in the PVP group than in the DVIU group, with no significant differences in surgical complications between the two groups. Additionally, the two groups exhibited substantial improvement in maximum urinary flow rate, residual urine volume, IPSS score and QoL score post-operation, without clear inter-group differences. These findings are in line with data from current studies and indicate that the direct-output green light laser method is safer and more effective in reducing surgical injuries and bleeding.

A green light laser is a green-coloured laser with a wavelength of 532 nm, known for its unique property of being highly absorbed by haemoglobin while not being absorbed by water, also referred to as a selective laser (Wang et al., 2020). Due to the advantage of high selective absorption of the green light laser, cutting, haemostasis and coagulation can be performed simultaneously during surgery, resulting in almost zero blood loss and ensuring a clear surgical field, which is crucial for the successful completion of endovascular surgeries for urethral strictures, allowing clinicians to target their interventions effectively. Moreover, another surgical advantage of the green light laser lies in its shallow tissue penetration (approx. 0.8 mm) (Yang et al., 2010), which minimises damage to the urethra and surrounding tissues, thereby reducing the risk of collateral damage, urinary extravasation, penile hematoma and urinary fistula, as confirmed in this study. Furthermore, the green light laser vaporises tissue while simultaneously forming a coagulation layer with a thickness of 1 to 2 mm on the surface, reducing fluid absorption and extravasation. In addition, the green light laser can simultaneously vaporise scar tissue, enlarge the passage and provide a neat wound surface within the urethra in the process of releasing urethral scar tissue, creating favourable conditions and a solid foundation for subsequent urethral mucosal healing.

Through this study, valuable insights into the success of direct-output green light laser urethrotomy have been obtained as follows. (a) For case selection, it is essential to reasonably grasp the indications for urethrotomy, and urethroplasty is recommended for long-segment strictures or patients with failed urethral surgery. (b) Perioperative prevention and control of urethral infection can reduce the probability of postoperative recurrent urethral strictures, and sensitive antibiotics are recommended based on the results of urine culture. (c) Safe guidewire placement is crucial for the entire procedure; otherwise, the surgery may go awry, leading to the formation of false passages. For urethral atresia, a urethral probe should be placed through a cystostomy channel to the proximal end of the urethra during surgery and twitched repeatedly to locate an appropriate incision site. (d) The green light laser power should not be set too high, primarily low power (30–80 W) in most cases, with 40 W recommended (X. L. Liu et al., 2009; Sun et al., 2016; Zhang et al., 2018). For stenosis at the bladder neck or prostate, or for dense scar tissue in the urethra, the power can be moderately increased. (e) Gradual vaporisation of scar tissue should be performed progressively to gradually enlarge the cavity. (g) Silicone catheters should be selected for indwelling urinary catheters, which should not be excessively large, with sizes of 18 to 22 F typically selected (Zhou et al., 2016). Additionally, the duration of indwelling catheters should not be too short (generally 3–6 weeks), as studies have indicated that urethral epithelial repair takes around 3 weeks and the crawling of the urethral mucosal epithelium takes around 6 weeks. (h) Regular urethral dilation postoperatively is the key to the success or failure of the surgery. Specifically, urethral dilation can reduce the recurrence of strictures following urethrotomy (Lv et al., 2016; Morey, 2017; Regmi et al., 2018).

However, this study has certain limitations. First, the sample size is relatively small and it is a retrospective study. The lack of randomisation and the relatively small sample size could introduce selection bias. Additionally, the potential for performance bias exists, as the surgical procedures were performed by a single surgeon, although efforts were made to ensure consistent technique across all cases. Furthermore, the termination of two surgeries in the DVIU group due to significant surgical bleeding may introduce performance and detection bias, as these cases were excluded from the final analysis, potentially affecting the overall outcomes. Furthermore, the relatively short follow-up time. Additionally, preoperative evaluation for the depth of spongiofibrosis was not conducted in this study. The presence of more extensive spongiofibrosis could result in a more challenging dissection during DVIU, potentially leading to longer surgical times and increased blood loss. Therefore, these conclusions should be considered preliminary, and further larger randomised trials with long-term outcomes, are necessary to draw more definitive conclusions regarding efficacy.

Conclusion

In conclusion, it is believed that direct-output green light laser treatment for short-segment (<2 cm) urethral strictures in men is safe and effective, with less damage, less bleeding and fewer complications, thereby making it worthy of further promotion and application in clinical practice.

Footnotes

Acknowledgements

None.

ORCID iD

Zongyao Hao

Ethical Considerations

This study was conducted in accordance with the declaration of Helsinki. This study was approved by Anqing Municipal Hospital.

Consent to Participate

The written informed consent was waived due to the retrospective nature of the study and the use of anonymised data in accordance with the Declaration of Helsinki and local regulatory requirements.

Author Contributions/CRediT

Conceptualisation: W QF;

Methodology: B T;

Formal analysis and investigation: C ZJ & H ZY;

Writing—original draft preparation: W QF;

Writing—review and editing: W QF & H ZY.

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship and/or publication of this article: This study was supported by the Genitourinary System Diseases Anhui Key Laboratory open project fund (2022APKLGUD09).

Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.

Data Availability

All data generated or analysed during this study are included in this article.

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