Given that prostate size may influence perioperative performance, functional outcomes, and safety, we performed an exploratory subgroup analysis for patients with TRUS-estimated prostate volumes ≥150 mL (n = 35; 18 LBL, 17 en-bloc). In this subgroup, the en-bloc group had numerically shorter operative time (92 ± 36.7 vs. 113.5 ± 31 min), shorter enucleation time (71.4 ± 30.4 vs. 84.3 ± 21.4 min), and lower total laser energy use (152.4 ± 41 vs. 166.2 ± 39 kJ) compared with the LBL group. Bladder injury occurred in 4 LBL patients versus none in the en-bloc group, and the need for electrocautery for hemostasis was noted in 3 vs. 1 patient, respectively. At 2 weeks, stress urinary incontinence was observed in 3 en-bloc patients versus none in the LBL group, with only one patient remaining incontinent at 1 month. These data are detailed in (Supplementary Table 1).
The classical three-lobe technique for HoLEP offers the theoretical advantage of a step-by-step enucleation. It divides the procedure into smaller, more manageable steps, while providing clear reference points, borders, and landmarks. This method provides clear anatomical reference points and is particularly useful in prostates with a prominent middle lobe. However, it also has notable limitations. First, it requires three separate incisions, which may increase the risk of leaving residual adenomatous tissue due to inconsistent dissection planes. Additionally, the traditional approach lacks EAR, which increases the risk of mucosal trauma to the EUS. This typically occurs due to downward levering of the scope during the 12 o'clock incision, potentially leading to transient stress urinary incontinence (SUI). The reported incidence of transient SUI after classic HoLEP can reach up to 30% even in the hands of experienced surgeons [13].
To address these issues, en-bloc enucleation with EAR, developed first by Sancha et al. in 2015 using the Green Light Laser [16] was introduced. The potential advantages of this technique include: 1) preserving the integrity of the mucosal covering of the EUS by early demarcation of the 'white line,' between the prostatic apex and EUS, 2) dissecting the anterior zone from the sides, lowering the adenoma and eliminating the need for downward levering of the scope, thus avoiding the splitting of the sphincter that can result from the traditional 12 o'clock incision; 3) improved visibility, as irrigation fluid is restricted to a narrower area; and 4) reduced operative time, as the adenoma is dissected apically from the EUS, enabling a circumferential line of dissection that speeds up the procedure because a single plane of dissection is followed throughout the procedure. In 2019, Saitta et al. replicated these principles using HoLEP and reported shorter overall operative time compared to other methods, with a lower incidence of SUI (1.5% at three months) [18].
Some authors have applied the principles of EAR and urethral sphincter mucosal preservation to the lobe-by-lobe technique, reporting improved outcomes, particularly in terms of a reduced incidence of early urinary incontinence [17, 20]. In this study we compared both en-bloc vs lobe by lobe HoLEP while ensuring that both techniques incorporated EAR and careful sphincteric mucosal preservation. This allowed us to isolate the impact of the enucleation strategy itself on perioperative and functional outcomes.
We identified several key findings. First, the en-bloc technique was associated with significantly shorter enucleation and operative times and required less laser energy compared to the LBL approach, despite comparable enucleated tissue weights. These observed intraoperative advantages of en-bloc HoLEP may be attributed to maintaining a consistent dissection plane and avoiding repeated lobe repositioning. While enucleation and operative efficiency were numerically higher in the en-bloc group, these differences did not reach statistical significance. This finding is likely explained by the comparable resected prostate weights between groups, which narrowed the absolute difference in efficiency values. Additionally, variability in operative performance across individual cases -- reflected in the relatively wide standard deviations for enucleation time and tissue weight -- may have limited the statistical power to detect a significant difference in this derived metric. Importantly, as the primary endpoint (enucleation efficiency) is a derived variable expressed as a ratio (grams/minute), it inherently carries increased variability due to the combination of two independent measures: enucleation time and enucleated weight. This additional variability may have further limited the statistical power to detect a significant difference in this metric, despite clear significant differences in one of its constituent components (enucleation time). Future studies should carefully account for this increased variability when calculating the sample size for derived ratio endpoints."
Our findings were consistent with previously published data. In a RCT comparing en-bloc vs 2-lobe vs 3 lobe HoLEP, Rucker et al. [23] reported a significantly higher operative efficiency for en-bloc and two-lobe compared to three-lobe (1.82, 1.76 and 1.67 gm/min, respectively P = 0.006) with no significant difference between en-bloc and two-lobe techniques. Similarly, Tuccio et al. [24], in a retrospective analysis, found that enucleation time, operative times and laser energy were significantly lower in the en-bloc compared to three-lobe technique. It is however worth noting that the mean prostate volume in the current study was notably larger than in the previous studies.
Second, we evaluated postoperative continence using a robust approach combining objective pad test measurements and subjective ICIQ-SF assessments, allowing a more accurate comparison between en-bloc and lobe-by-lobe (LBL) HoLEP techniques. At three months, the incidence of stress urinary incontinence (SUI) was 3.8% in the en-bloc group and 4% in the LBL group, without significant difference. These rates are notably lower than the historically reported incidence of SUI following conventional HoLEP techniques, where transient SUI rates reached up to 30%. Our findings align with prior studies that implemented similar technical modifications. For instance, Saitta et al. [18] reported a 1.5% SUI rate at three months in 137 patients undergoing en-bloc HoLEP. Similarly, Tuccio et al. [24] compared en-bloc HoLEP with EAR to the lobe-by-lobe technique and found a significantly lower incidence of SUI at one month in favor of the en-bloc (4.5% vs. 13.5%, P < 0.05).
In a large multicenter study involving over 5000 patients, the incidence of SUI was significantly higher in the LBL group compared to the en-bloc group. Furthermore, the absence of EAR was identified as an independent predictor of SUI on multivariate analysis [25]. Interestingly, Rucker et al. [23] found no statistically significant difference in SUI incidence among en-bloc, two-lobe, and three-lobe techniques within the first three months (5%, 4%, and 5.5%, respectively; P = 0.8), though they used a binary (yes/no) question to assess SUI. The slightly higher SUI rates observed in our study could be attributed to the use of more sensitive assessment methods, including the pad test, which likely captured milder degrees of incontinence.
Although the present study was not specifically powered to detect subtle differences in continence outcomes, our findings suggest that with consistent EAR, continence outcomes are similarly favorable regardless of enucleation technique. Future trials aiming to explore the potential continence benefits of en-bloc HoLEP should be designed as large, multicenter studies, as detecting minor differences may require substantially greater statistical power. Finally, these results support shifting focus from continence -- once EAR is standardized -- to operative efficiency, precision, and safety as primary endpoints comparing en-bloc and LBL techniques.
Third, we found that both the en-bloc and lobe-by-lobe HoLEP techniques yielded comparable functional outcomes, as reflected by significant and sustained improvements in IPSS, QoL, PVR, and Q max at all follow-up time points. This confirms both techniques effectively relieve obstruction and improve function. Fourth, in the exploratory subgroup analysis of prostates >150 mL, trends favored the en-bloc technique in terms of shorter operative and enucleation times and lower laser energy use. Early stress urinary incontinence at 2 weeks was observed more frequently in the en-bloc group, but this largely resolved by 1 month. Conversely, the lobe-by-lobe group demonstrated a higher frequency of bladder injury and greater use of auxiliary hemostatic procedures. These findings highlight that both techniques have potential advantages and limitations in very large prostates. As the present study was not powered for this subgroup, dedicated trials specifically addressing optimal technique selection in such cases are warranted. Additionally, no significant differences in intraoperative or 30-day postoperative complications were found, suggesting comparable safety profiles when performed by experienced surgeons. These complication rates were also consistent with those reported in previously published studies [26]. Thus, technique selection can depend on surgeon experience without compromising outcomes.
Finally, our study offers several strengths. It is the first randomized controlled trial comparing en-bloc and lobe-by-lobe HoLEP incorporating both Early Apical Release (EAR) and external urethral sphincter mucosal preservation. The use of standardized dual-modality continence assessment -- objective (pad test) and subjective (ICIQ-SF) -- ensured a comprehensive and reliable evaluation. However, there are some limitations to be acknowledged. First, sexual function was not assessed, as a large proportion of patients were not sexually active preoperatively. Second, the study was conducted at a single high-volume center, and all procedures were performed by experienced endourologists, limiting the generalizability of our findings. Third, although the follow-up period was sufficient to capture early and intermediate outcomes, a longer follow-up is needed. Finally, the study was not powered to detect small differences in early urinary incontinence rates between both techniques. Further multicenter, prospective studies are warranted to assess the learning curve and long-term functional outcomes of different HoLEP techniques.