With the increasing degree of population aging, the number of patients undergoing surgical treatment for benign prostatic hyperplasia (BPH) is steadily rising. Among them, patients with small-volume prostates (≤30 mL) represent a distinct clinical subgroup.

This population has several unique characteristics:

1. Approximately 17.5% of patients show suboptimal postoperative outcomes.
2. The incidence of postoperative bladder neck contracture (BNC) is relatively high, reaching up to 19.3% in some reports.

In addition, the pathophysiological mechanisms of small-volume BPH are different from those of larger prostates. These include increased fibrotic tension of the bladder neck and bladder neck elevation.

At present, there is no clearly established surgical approach specifically designed to further improve postoperative outcomes or effectively prevent bladder neck contracture in patients with small-volume BPH.

This study primarily compares the safety and efficacy of transurethral thulium laser enucleation of the prostate (ThuLEP) versus ThuLEP combined with bladder neck incision in the treatment of small-volume benign prostatic hyperplasia (BPH), with the aim of further optimizing surgical management strategies for small prostates and reducing the incidence of postoperative complications.

Benign prostatic hyperplasia (BPH) is a common urological disease in middle-aged and elderly men. With the acceleration of population aging in China, the incidence of BPH is continuously increasing. Domestic epidemiological data show that the prevalence of histological BPH is approximately 20% in men aged 50-60 years, 50% in those aged 61-70 years, 57.1% in those aged 71-80 years, and 83.3% in those aged 81-90 years. BPH leads to bladder outlet obstruction and changes in lower urinary tract symptoms, thereby significantly affecting patients' quality of life, and in advanced stages may result in bladder and renal dysfunction.

Transurethral resection of the prostate (TURP) has long been regarded as the "gold standard" for the surgical management of BPH by urologists. However, its application is limited by relatively high rates of postoperative complications, including bleeding, bladder neck contracture, urethral stricture, TUR syndrome, and a considerable reoperation rate. With the development and increasing application of laser technologies in urology, laser-based procedures have demonstrated growing advantages in the treatment of BPH.

Thulium (Tm) laser is a novel medical laser technology with a wavelength range of 1.75-2.22 μm. Thulium laser technology is characterized by simplicity of operation, minimal tissue injury, excellent hemostatic capability, and high precision. In recent years, it has developed rapidly and been widely adopted in urology. Transurethral thulium laser enucleation of the prostate is considered safe and efficient, with an easy learning curve, relatively short training period, and lower procedural cost, thus demonstrating broad clinical prospects.

The pathophysiology of bladder outlet obstruction in BPH can be divided into two major components: dynamic factors (increased smooth muscle tone of the prostate) and mechanical factors (urethral compression due to prostate enlargement) . Unlike large prostates (>80 mL), in most small-volume BPH cases, mechanical compression of the posterior urethra is not the predominant cause of obstruction. Some studies suggest that the main pathophysiological mechanisms in small prostates include bladder neck fibrosis, increased fibrous ring tension, and chronic prostatitis . In addition, bladder neck elevation and an increased prostatic urethral angle are also closely associated with lower urinary tract obstruction symptoms in this population.

Based on these considerations, we propose a combined surgical approach consisting of transurethral laser enucleation of the prostate combined with bladder neck longitudinal incision. By surgically incising the bladder neck, this technique may simultaneously address both prostatic hyperplasia and bladder neck abnormalities. For patients with small prostates accompanied by bladder neck stenosis, fibrosis, or anatomical abnormalities (such as bladder neck elevation), this combined procedure may effectively correct both tissue obstruction and bladder neck dysfunction in a single stage.

Our center previously conducted a retrospective analysis on the efficacy and safety of thulium laser enucleation combined with bladder neck incision in the treatment of small-volume BPH. The study included 20 patients treated between June 2024 and December 2024. The patients were aged 63-77 years, with a mean age of 73 years. Prostate volume ranged from 19 to 29 mL, with a mean of 26 mL. All patients achieved satisfactory immediate urinary continence. With a follow-up period exceeding 12 months, no cases of bladder neck contracture were observed. The results suggest that thulium laser enucleation combined with bladder neck incision is an effective and safe treatment option for small-volume BPH.

For small-volume BPH, transurethral incision of the prostate (TUIP) is a guideline-recommended standard procedure. The core technique involves incision of the bladder neck and prostatic urethra, typically performed at the 5 o'clock and 7 o'clock positions, with partial resection of bladder neck tissue.

In the present study, the experimental group underwent only a single bladder neck incision at the 6 o'clock position following thulium laser enucleation. The depth of incision was consistent with that of TUIP. The incision was neither extended nor increased in number, resulting in minimal trauma to the bladder neck. Theoretically, this approach does not increase the risk of complications such as bleeding, urinary incontinence, urethral stricture, or bladder neck contracture, and is supported by sound anatomical rationale and clinical safety considerations.

This study is a multicenter, randomized, single-blind clinical trial. The study population consists of male patients aged 50-85 years who meet the diagnostic criteria for benign prostatic hyperplasia (BPH) and require surgical intervention.A centralized randomization system will be used, and 120 participants will be allocated in a 1:1 ratio to the control group and the intervention group.

Group allocation and interventions:

Intervention group (n = 60): Transurethral thulium laser enucleation of the prostate (ThuLEP) combined with bladder neck incision.

Control group (n = 60): Transurethral thulium laser enucleation of the prostate (ThuLEP) alone.

Study duration: Patients will be followed up until 6 months postoperatively.

Primary objective:

To evaluate the improvement of postoperative lower urinary tract symptoms in patients with small-volume benign prostatic hyperplasia (BPH) treated with transurethral thulium laser enucleation of the prostate combined with bladder neck incision.

Primary outcome measure:

The maximum urinary flow rate (Qmax) at 6 months postoperatively in patients with small-volume BPH, which will also be used for sample size calculation.

Secondary objective 1:

To evaluate the safety and overall efficacy of transurethral thulium laser enucleation of the prostate combined with bladder neck incision in the treatment of small-volume BPH.

Outcome measures 1:

Perioperative vital signs; complete blood count; liver and renal function tests; serum electrolytes; and urinalysis. Intraoperative and early postoperative complications will be recorded, including severe bladder spasms, hematuria, and urinary tract injury or perforation. At 6 months postoperatively, IPSS score, post-void residual urine volume, and quality of life (QoL) will be assessed. Clinical outcomes will also include recurrence of voiding difficulty, weak urinary stream, and reduced urinary force, as well as the rates of urethral dilation, cystoscopy, and reoperation.

Secondary objective 2:

To assess the incidence of postoperative bladder neck contracture between the two groups.

Outcome measure 2:

The incidence rate of bladder neck contracture during the follow-up period in both groups.

Inclusion Criteria:

• Male patients aged 50-85 years who meet the diagnostic criteria for benign prostatic hyperplasia (BPH), with a prostate volume ≤30 mL and requiring surgical intervention.
• Preoperative International Prostate Symptom Score (IPSS) ≥8.
• Preoperative maximum urinary flow rate (Qmax) ≤15 mL/s.
• Bladder capacity ≥150 mL.
• Willing to participate in this clinical trial and has signed the informed consent form.
• Able to communicate well with investigators and comply with the study protocol requirements.

Exclusion Criteria:

• Patients with urethral stricture in whom passage of surgical instruments is not feasible.
• Total PSA >10 ng/mL, or PSA between 4-10 ng/mL with a free-to-total PSA ratio <0.16, and confirmed malignancy on biopsy.
• Coagulation disorders, including platelet count <80 × 10⁹/L.
• Uncontrolled urinary tract infection.
• Neurogenic bladder.
• Presence of malignant tumors.
• Urodynamic diagnosis of bladder neck sclerosis, detrusor underactivity, detrusor-sphincter dyssynergia, or unstable bladder.
• Contraindications to surgery, such as severe cardiopulmonary disease.
• Cognitive impairment, including senile dementia, cerebral atrophy, acute cerebrovascular disease, sequelae of cerebrovascular disease, or other conditions affecting cognitive function.
• History of suprapubic cystostomy for benign prostatic hyperplasia.
• Acute localized or systemic bacterial infection that has not been effectively controlled.
• Presence of shock or other critical conditions that preclude cooperation with the procedure and outcome evaluation.
• Psychiatric or neurological disorders preventing cooperation with the study.
• Participation in another clinical trial within 1 month prior to enrollment.
• Any other condition deemed inappropriate for inclusion by the investigators.