Ejaculation-Preserving Versus Conventional Dual Wavelength Diode Laser Vaporization of the Prostate

BACKGROUND

Loss of antegrade ejaculation follows conventional transurethral resection or vaporization of the prostate in the majority of men. Two anatomical regions are considered central to this: the internal urethral sphincter at the bladder neck, which prevents retrograde passage of semen, and the paracollicular and supracollicular tissue around the verumontanum, which contributes to the emission phase. Techniques preserving one or both regions have been described across several endoscopic platforms, but evidence specific to the dual-wavelength diode laser is limited and follow-up in previous work has been short.

OBJECTIVE

To determine whether an ejaculation-preserving technique of dual-wavelength diode laser vaporization of the prostate preserves antegrade ejaculation without compromising relief of bladder outlet obstruction, and whether any benefit is durable to 12 months.

DESIGN

Prospective, randomized, single-centre comparative study conducted at the Department of Urology, Royal Hospital, Sulaymaniyah, Kurdistan Region, Iraq. Allocation followed a computer-generated random sequence, with assignments concealed in sequentially numbered opaque sealed envelopes opened after consent. Participants were not informed of their allocation. The operating surgeon was necessarily aware of allocation.

INTERVENTION

All procedures were performed by a single surgeon under spinal or general anaesthesia, using a 22 Fr continuous-flow laser cystoscope sheath with normal saline irrigation. Energy was delivered by a Ceralas dual-wavelength diode laser system (biolitec biomedical technology GmbH, Jena, Germany) emitting simultaneously at 980 nm and 1470 nm, through a bare-tip fibre in continuous-wave mode at a total power of 140 W. Laser wavelength, fibre type, emission mode and power setting were identical in both arms.

Conventional arm: vaporization proceeded from the bladder neck to the verumontanum in the standard fashion, including tissue at the bladder neck and immediately proximal to the verumontanum, until a wide channel was created.

Ejaculation-preserving arm: no vaporization was performed within 10 mm distal to the bladder neck, and no vaporization was performed within 10 mm proximal to the verumontanum. Between these two margins, the lateral lobes, median lobe and anterior tissue were vaporized to the same endpoint as in the conventional arm. Adherence to both margins was recorded prospectively in every case.

ASSESSMENTS

Participants were assessed at baseline and at day 7 to 14, 1 month, 3 months, 6 months and 12 months. Symptoms were quantified with the International Prostate Symptom Score and its quality-of-life item, and erectile function with the five-item International Index of Erectile Function. Uroflowmetry was accepted only with a voided volume of at least 150 mL. Post-void residual volume and prostate volume were measured by transabdominal ultrasound. Ejaculatory status was recorded as a binary patient-reported outcome: presence or absence of any antegrade ejaculate during sexual activity since the preceding visit. Complications were graded using the Clavien-Dindo classification.

ANALYSIS

Continuous variables were compared between arms with the Mann-Whitney U test and within arms against baseline with the Wilcoxon signed-rank test. Proportions were compared with the two-sided Fisher exact test, with risk differences reported using Newcombe hybrid-score 95 percent confidence intervals. No imputation was performed. Analysis was restricted to participants with complete records at every scheduled visit.

NOTE ON REGISTRATION

This trial was registered retrospectively. The protocol, including the primary endpoint, the secondary endpoints and the two 10 mm technical margins, was submitted to and registered by the Scientific Committee of the Department of Clinical Sciences, College of Medicine, University of Sulaimani (number 28, 25 February 2025) and approved by the Ethics Committee of the same institution (number 62, 2 March 2025). Public registry registration was not undertaken before enrolment because the requirement was not appreciated at the time. No outcome measures, eligibility criteria or analysis definitions were altered after the study began.