BOOI‐Defined Obstruction Stratifies Early Outcomes After ThuLEP in Men With Detrusor Underactivity: A Retrospective Complete‐Case Cohort Study

BACKGROUND: The benefit of transurethral outlet surgery in men with benign prostatic enlargement/benign prostatic obstruction (BPE/BPO) and detrusor underactivity (DU) remains uncertain, particularly when bladder outlet obstruction (BOO) is not demonstrated by pressure-flow testing. OBJECTIVE: To evaluate early outcomes after transurethral thulium laser enucleation of the prostate (ThuLEP) in men with DU and BPE/BPO-related voiding dysfunction, and to examine whether BOOI-defined obstruction status stratifies early postoperative improvement. METHODS: We retrospectively reviewed 189 ThuLEP records from a single centre and constructed a 100-patient complete-case cohort with interpretable preoperative pressure-flow studies and 3-month follow-up. DU was defined as bladder contractility index (BCI) < 100. BOO status was classified using bladder outlet obstruction index (BOOI) as definite BOO, equivocal BOO or no BOO. Functional, symptom, catheter-removal, anatomical and safety outcomes were compared descriptively across BOO strata. RESULTS: increased from 3.88 ± 1.76 mL/s at baseline to 9.98 ± 3.68 mL/s at 1 month and 11.03 ± 4.02 mL/s at 3 months (both p < 0.001). Mean PVR decreased from 267.8 ± 167.4 to 142.6 ± 115.3 mL and 124.7 ± 103.4 mL, respectively (both p < 0.001). IPSS and QoL also improved. Because enucleated specimen weight was unavailable, postoperative prostate volume was analyzed as an anatomical surrogate; mean 3-month postoperative prostate volume was 18.8 ± 4.3 mL, corresponding to an absolute volume reduction of 38.0 ± 14.2 mL and a percentage reduction of 65.4% ± 6.3% in the DU cohort. Catheter-removal success was 83.9% in definite BOO, 68.0% in equivocal BOO and 40.0% in no BOO patients (descriptive p = 0.009). CONCLUSIONS: Preoperative BOOI-based stratification may help counsel men with DU regarding expected early functional improvement after ThuLEP. BOOI-defined no-BOO patients in this cohort were clinically selected after counseling, and the findings should be interpreted as exploratory because of the retrospective design, complete-case selection, short follow-up, and the small no-BOO subgroup.