We conducted a prospective, single-center study at Monaldi Hospital (Naples, Italy) between June 2022 and June 2024. The study adhered to the principles outlined in the Declaration of Helsinki for medical research involving human subjects¹⁴ and was approved by the University of Campania Luigi Vanvitelli-A.O.R.N. dei Colli Ethics Committee (approval number: 11566/2022). All participants provided written informed consent for inclusion of their data in the study database and for their use in scientific publications.

Consecutive male patients with BPO secondary to BPH who were refractory to medical therapy and were candidates for ThuVAP at our institution were considered for inclusion.

Eligible patients were aged ≥40 years, had moderate-to-severe LUTS defined by an International Prostate Symptom Score (IPSS) ≥8¹⁵ or the presence of an indwelling urinary catheter despite optimized BPH medical therapy, a prostate volume ≤80 mL on transrectal ultrasonography, and urodynamically confirmed bladder outlet obstruction (BOO) according to International Continence Society (ICS) criteria.^16,17

Exclusion criteria comprised prior prostatic surgery; suspected or documented prostate cancer (PCa); history of pelvic radiotherapy; neurogenic lower urinary tract dysfunction; history of bladder cancer; presence of bladder stones; previous urethral stricture or urethral reconstruction; chronic bacterial prostatitis; recurrent urinary tract infections (UTIs); chronic pelvic pain syndrome; uncontrolled diabetes. Patients with severe, uncontrolled comorbidities that contraindicated anesthesia or endoscopic surgery were excluded. Men with psychiatric disorders or an inability to complete the questionnaires were also excluded, as were subjects with missing data. Ongoing anticoagulant or antiplatelet therapy that could not be discontinued was not considered an exclusion criterion.

All patients underwent a comprehensive baseline evaluation, including demographic data, general clinical parameters, and BPO-specific history. Preoperative assessment comprised digital rectal examination (DRE), serum prostate-specific antigen (PSA) measurement, transrectal ultrasonography (TRUS) for prostate volume determination, IPSS, uroflowmetry with postvoid residual (PVR) volume determination, and invasive urodynamic testing. The presence of a median lobe was determined intraoperatively by endoscopic identification of intravesical protrusion; no ultrasound measurements or dimensional cut-off criteria were applied. No fixed PSA cutoff was applied as a sole exclusion criterion. In cases of elevated PSA and/or abnormal DRE, patients underwent mpMRI and, when indicated, targeted and/or systematic prostate biopsy. All patients with clinical suspicion or histological confirmation of prostate cancer were excluded from enrollment.

Urodynamic studies were performed at baseline (T0) and at 6 months postoperatively (T1) in accordance with ICS standards,¹⁷ and were conducted in all cases by the same experienced functional urologist to ensure methodological consistency. The primary outcome was the change in the Bladder Outlet Obstruction Index (BOOI) from T0 to T1. According to the International Continence Society (ICS) definition, a BOOI ≥40 was considered obstruction, 20–40 equivocal, and <20 as no obstruction.¹⁸ Secondary urodynamic outcomes included functional, normal, and strong desire to void capacities (first desire to urinate [FDU], normal desire to urinate [NDU], strong desire to urinate [SDU]); maximum cystometric capacity (MCC); low bladder compliance (LBC, defined as ≤20 mL/cmH₂O;)¹⁹ presence of involuntary detrusor contractions (IDC) and detrusor pressure at IDC; detrusor pressure at opening of flow (P_det at opening); detrusor pressure at maximum flow (P_detQ_max); maximum detrusor pressure during voiding (P_det, _max); maximum urinary flow rate during the pressure-flow study (Q_max); time to maximum flow (tQ_max); voiding time (VT); postvoid residual volume (PVR) and proportion with PVR ≥ 100 mL; bladder voiding efficiency (BVE); bladder outlet obstruction index (BOOI), proportion with BOOI ≥ 40; bladder contractility index (BCI); and Schäfer nomogram grade.²⁰

The International Prostate Symptom Score (IPSS) questionnaire, defined a priori as a secondary clinical endpoint, was administered at baseline (T0) and at 6 months postoperatively (T1). Free uroflowmetry was obtained at baseline and subsequently at 3, 6, and 12 months postoperatively.

Perioperative variables—such as operative time, catheterization time, length of hospital stay, and need for blood transfusion—were recorded for all patients. Intraoperative complications and postoperative adverse events were systematically documented, with postoperative events classified according to the Clavien-Dindo (CD) grading system.²¹ During follow-up, any initiation or resumption of medical therapy for BPO or any surgical re-intervention for persistent obstruction was recorded. All patients completed a minimum follow-up of 12 months.

All patients underwent preoperative urine culture, and surgery was performed only in cases with negative results or after resolution of a documented UTI, confirmed by repeat culture following appropriate antibiotic therapy. Perioperative antibiotic prophylaxis, in accordance with the institutional protocol, consisted of a single intravenous dose of ceftriaxone (1 g) administered 30–60 min before the start of the procedure.

In all cases, a high-power continuous-wave thulium:YAG laser (Cyber TM, Quanta System, Italy) was used, delivering 200 W for vaporization and 30 W for hemostasis through an 800 μm end-firing fiber. The laser was operated via a 26 Ch continuous-flow resectoscope (KARL STORZ SE & Co. KG, Tuttlingen, Germany) with a 12° lens and an Iglesias working element, under continuous 0.9% saline irrigation. Vaporization was performed using a two- or three-lobe approach, depending on the presence of a median lobe. The procedure began with bladder neck incisions at the 5 and 7 o’clock positions using a painting technique. When a prominent median lobe was present, vaporization was initiated at this site before proceeding to the lateral lobes. All lobes were vaporized down to the prostatic capsule.

Upon completion of the procedure, a 20 Ch three-way Dufour catheter was inserted. Per protocol, all patients left the operating room with slow continuous bladder irrigation to minimize clot formation and retention. Irrigation was usually discontinued within the first 12 h. Catheter removal was routinely scheduled between postoperative days (POD) 1 and 3, depending on the individual patient’s clinical course. As part of the postoperative protocol, patients were advised to take ibuprofen primarily as an anti-inflammatory measure to reduce transient urinary discomfort and irritative symptoms, especially after catheter removal. The medication was prescribed for up to 7 days, with subsequent use on an as-needed basis. No nutraceutical agents were administered. All pharmacological treatments for BPO were discontinued from the time of surgery. The use of tadalafil 5 mg once daily for potential concomitant erectile dysfunction was not permitted during the study period.

Sample size calculation was performed a priori based on the primary outcome (change in BOOI from T0 to T1). Assuming an expected postoperative BOOI reduction of ≥20 points, as a conservative and clinically meaningful target, and an estimated standard deviation of the paired differences of 23,^22,23 a paired two-tailed t-test with α = 0.05 and 80% power yielded a minimum required sample size of 13 patients. To account for a potential 20% attrition rate, the planned enrollment was increased to 16 patients.

Continuous variables were expressed as mean ± standard deviation [SD] or median (interquartile range [IQR]), depending on the distribution assessed by the Shapiro–Wilk test. Categorical variables were reported as absolute frequencies and percentages. Comparisons between T0 and T1 for continuous variables were performed using the paired t-test or Wilcoxon signed-rank test, as appropriate according to their distribution. Paired dichotomous variables were compared using McNemar’s test. For paired categorical outcomes with more than two levels, the Stuart–Maxwell test for marginal homogeneity was applied. Continuous paired variables were analyzed with paired t-tests or Wilcoxon signed-rank tests as appropriate. Continuous variables were graphically illustrated using paired dot plots or bar plots, while categorical variables were visualized using stacked bar charts.

The primary association between urodynamic de-obstruction and symptom relief was assessed using ANCOVA with IPSS at 6 months as the dependent variable, BOOI at 6 months as the main predictor, and baseline IPSS as a covariate. Additional models adjusted for baseline BOOI and clinically relevant covariates (age, prostate volume, Q_max, PVR). Sensitivity analyses included the correlation between changes (ΔIPSS vs. ΔBOOI) and responder analyses based on BOOI thresholds (unobstructed < 20; obstructed > 40; equivocal 20–40).

All statistical tests were two-tailed, and p-values < 0.05 were considered statistically significant. Analyses were conducted using R software v.4.5.1 (R Foundation for Statistical Computing, Vienna, Austria) within the RStudio environment v.2025.05.1+513 (Posit, Boston, MA, USA).

In this prospective study, ThuVAP demonstrated substantial urodynamic de-obstruction at six months. The mean BOOI decreased from 55.9 ± 13.4 to 21.3 ± 10.4, reducing the proportion of patients classified as obstructed from 79.7% to 7.8%. Pressure–flow analyses revealed a marked decline in detrusor pressure at maximum flow (P_detQ_max: 58.1 ± 24.2 to 32.5 ± 14.1 cmH₂O), accompanied by a significant increase in maximum urinary flow (Q_max: 10.3 ± 4.3 to 17.7 ± 7.0 mL/s). Moreover, detrusor overactivity resolved in nearly three-quarters of affected patients, and the prevalence of low bladder compliance decreased from 18.8% to 3.1%. Importantly, lower postoperative BOOI values were independently associated with greater symptom relief, underscoring the clinical relevance of urodynamic de-obstruction. Collectively, these results indicate that ThuVAP produces consistent and meaningful improvements across obstruction, voiding, and storage domains. Direct comparisons with the literature are difficult, as few ThuVAP studies have reported paired urodynamic outcomes. A large retrospective 200-W ThuVAP series provided baseline pressure–flow data but no postoperative urodynamic follow-up, instead focusing on clinical parameters such as IPSS, Q_max, and PVR.²⁴ Similarly, a prospective ThuVAP cohort reported early improvements in these same clinical outcomes, but did not include pressure–flow testing after surgery.²⁵

Against this backdrop, contextualization with established procedures is essential. Conventional TURP remains the reference standard for prostates between 30 and 80 mL, with EAU 2024 guidelines recommending monopolar or bipolar TURP as the first-line intervention when medical therapy fails.²⁶ Randomized controlled trials and meta-analyses consistently confirm robust and durable improvements in IPSS, Q_max, and PVR following TURP.²⁷

Holmium laser enucleation of the prostate (HoLEP) has been extensively benchmarked against TURP in the same prostate volume range. Comparative studies demonstrate equivalent efficacy in both functional and urodynamic outcomes, with HoLEP offering advantages in transfusion requirements, catheterization duration, and hospital stay, albeit at the expense of longer operative times.^28–30

Minimally invasive surgical therapies (MIST) such as Aquablation and Rezūm have also been evaluated in men with prostates <80 mL. The WATER randomized trial³¹ reported non-inferior IPSS and Q_max outcomes for Aquablation compared with TURP at five years, with a clear advantage in ejaculatory function preservation, though perioperative morbidity was slightly higher. More recently, a multicenter randomized study comparing TURP, Aquablation, and Rezūm in prostates 30–80 mL found broadly similar improvements in LUTS, albeit with somewhat slower functional gains and lower flow improvements in the MIST arms.^32,33

Within this context, our findings suggest that ThuVAP achieves functional outcomes directionally comparable to TURP and HoLEP, particularly with respect to BOOI reduction and IPSS improvement. It also offers the intrinsic advantages of laser technology, including excellent hemostasis and a favorable perioperative safety profile. Unlike MIST procedures, however, ThuVAP did not preserve ejaculatory function in the majority of patients, underscoring trade-offs that should be carefully considered in treatment selection. Photoselective vaporization (PVP) provides an additional indirect comparator. In an 80-W KTP PVP series with paired urodynamic testing, BOOI decreased from 49.8 to 9.8, P_detQ_max from 68.7 to 40.6 cmH₂O, and the proportion of obstructed patients from 64% to 4% at six months.³⁴ Another prospective PVP study documented significant relief of outlet obstruction, with detrusor overactivity decreasing from 47.4% to 26.9%, while detrusor contractility remained largely unchanged.³⁵ Overall, our results align with these findings, reinforcing the physiological plausibility of a de-obstructive effect with ThuVAP, and highlight the need for dedicated prospective studies with standardized urodynamic endpoints.

This study represents, to our knowledge, the first prospective clinical trial to comprehensively assess paired pre- and postoperative urodynamic parameters after ThuVAP. Strengths include its prospective design, prespecified primary endpoint (BOOI) supported by an a priori power calculation, and a predefined secondary objective linking de-obstruction to symptom relief. Standardized urodynamic testing was performed by a single experienced functional urologist (RB), ensuring methodological consistency, while narrow inclusion and exclusion criteria and consistent laser parameters further enhanced internal validity.

Nevertheless, important limitations must be acknowledged. The absence of a comparator arm precludes direct conclusions relative to TURP, HoLEP, or MIST. The single-center design and strict eligibility criteria limit generalizability to broader BPH populations. While the study was sufficiently powered for its primary endpoint, the relatively modest sample size limited subgroup analyses and may have underestimated rare adverse events. Urodynamic follow-up was restricted to six months, and clinical follow-up to twelve months, preventing evaluation of late complications, long-term durability, and reoperation rates. Moreover, sexual outcomes were assessed only using the IIEF-5 and reporting of retrograde ejaculation, without the application of more comprehensive validated instruments such as the full IIEF or MSHQ-EjD. Finally, patient-reported outcomes were unblinded and may be subject to expectation bias, though the magnitude and consistency of improvement support the validity of the observed effects.

The restriction to prostates <80 mL introduces a notable selection bias, as this is precisely the group in which TURP remains the gold standard supported by randomized evidence and guideline recommendations. Therefore, our results should not be interpreted as demonstrating superiority over TURP, but rather as supporting ThuVAP as an effective alternative in carefully selected patients. In larger prostates, HoLEP or other enucleation techniques may offer superior long-term outcomes, highlighting the need for stratified comparative trials.

Finally, our adoption of PVR thresholds (>100 mL or >20% of bladder volume) as indicators of clinically significant incomplete emptying is supported by the literature. ICS guidance³⁶ identifies PVR >100 mL as a widely accepted cut-off associated with impaired emptying and increased risk of lower urinary tract dysfunction, while Rubilotta et al.³⁷ demonstrated that residual urine exceeding 20% of bladder volume correlates with impaired contractility and worse symptom severity. In our cohort, both absolute and relative PVR values improved markedly, with nearly all patients falling below clinically meaningful thresholds postoperatively. These results further substantiate the physiological plausibility of ThuVAP’s de-obstructive effect and the utility of standardized PVR criteria in assessing surgical efficacy.

Future studies should build on current evidence by conducting multicenter, randomized comparative trials to directly benchmark ThuVAP against gold-standard procedures and other laser techniques, using harmonized urodynamic endpoints and patient-reported outcomes. Larger sample sizes are required to enable reliable subgroup and multivariate analyses, particularly in relation to baseline obstruction severity, detrusor contractility, prostate volume, age, and the presence of a median lobe. Longer follow-up is essential to confirm the durability of functional improvements and to provide more reliable estimates of medical retreatment and reoperation rates. Broader eligibility criteria—including patients with larger prostates, prior procedures, or relevant comorbidities—would enhance external validity and generalizability. Finally, systematic assessment of sexual and ejaculatory function with validated outcome tools, together with economic and learning-curve evaluations, would help define the role of ThuVAP in contemporary BPO management.