Transurethral enucleation with bipolar (TUEB) using spatula loop is one of endoscopic enucleation methods for the surgical treatment of benign prostatic hyperplasia (BPH), and has more advantages in intraoperative hemostasis and specimen removal after enucleation. We investigated the learning curve and efficiency of TUEB using specialized spatula loop for patients with BPH.

Four hundred and ninety-four consecutive patients who underwent TUEB for BPH from August 2018 to March 2022 by a single surgeon were enrolled. To evaluate the learning curve of TUEB, perioperative parameters including TUEB efficiency (enucleated tissue weight/operation time), enucleation efficiency (enucleated tissue weight/enucleation time), and morcellation efficiency (enucleated tissue weight/morcellation time) were analyzed. The preoparative and postoperative functional outcomes and postoperative complications of all patients were also assessed, including the International Prostate Symptom Score (IPSS), quality-of-life score (QoLs) and uroflowmetry.

Median age of all patients was 72 years (Interquartile range [IQR] 66-78), while estimated prostate volume was 63.0 (IQR 46.0-90.6). In terms of operative efficiency, overall TUEB efficiency and enucleation efficiency were 0.21 gm/min (IQR 0.15-0.29) and 0.50 gm/min (IQR 0.35-0.72) respectively, reaching a plateau phase after consecutive 70 cases. The functional outcomes at 6 months postoperative improved substantially compared with baseline, including IPSS total score (9 vs. 20, p <0.001), QoLs (2 vs. 4, p <0.001), maximum urine flow rate (13 mL/sec vs. 9 mL/sec, p =0.006) and postvoid urine volume (17.5 mL vs. 76.0 mL, p <0.001). A total of 62 patients (13.2%) experienced overall complications after TUEB. There was a tendency of complication rates to decline as the number of TUEB cases increases, but without statistical significance (p =0.505).

To our best knowledge, there are only few studies on the learning curve of TUEB. The number of TUEB cases required to reach a plateau status in our study was 70 cases, with substantial improvements in functional outcomes at the 6-months follow-up compared with preoperative baseline values. However, the learning curve of 70 case for TUEB in our study was more than those of previous studies, ranging from 40 to 50 cases. Furthermore, perioperative outcomes such as TUEB efficiency or enucleation efficiency, and overall complication rates in our study was relatively inferior to those in previous study on learning curves of TUEB. These results could be partially explained by lack of structured mentoring system at our institution. There are several studies that stressed the importance of proper mentoring systems in the holmium laser enucleation of the prostate (HoLEP) and TUEB. Further study should be performed to evaluate the impact of mentor-based training system.

Our results suggest that the efficiency of TUEB using spatula loop reached a stable stage within 70 procedures, providing a significant improvement in functional outcomes.

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