Men with high urethral resistance related benign prostatic enlargement preoperatively benefit most from the relief of bladder outlet obstruction1. However, chronic bladder outlet obstruction results in structural and functional changes and reduction of contractility to the bladder wall. In such cases, it is difficult to differentiate the reduction of detrusor contractility from the bladder outlet obstruction. The ICS recommends pressure-flow studies before invasive therapy or when a precise diagnosis of bladder outlet obstruction is important2. This is especially obscure for urodynamically equivocal men with severe lower urinary tract symptoms (LUTS) associated with prostatic enlargement. Therefore, this study investigated the predicting factors affecting the successful outcomes after holmium laser enucleation of prostate in urodynamically equivocal men,

We retrospectively reviewed and analyzed the medical records of patients ≥ 40 years old suffering with LUTS who were preoperatively urodynamically equivocal and had undergone holmium laser enucleation of prostate. The urodynamically equivocal group was defined as 20≤ bladder outlet obstruction index (PdetQmax - 2*Qmax) <40 according to the provisional ICS method for the definition of obstruction. The successful outcomes for the surgery was defined as quality of life score on International Prostate Symptom Score (IPSS) ≤ 2 at postoperative 3 months. We compared preoperative factors such as age, prostate volume, IPSS, uroflowmetry parameters, post-void residual urine volume and urodynamic study parameters including the index for detrusor underactivity (Wmax <7 W/m2 and bladder contractility index (PdetQmax + 5*Qmax) <100)  between the patients with successful outcomes group and not-successful outcomes group.

We enrolled 24 patients. Mean patient age was 67.5 ± 9.7 years (range 51 to 88). Mean prostate volume was 42.7 ± 21.4 ml (range 20 to 97.9). Mean total IPSS score was 20.9 ± 9.4 (range 6 to 32). Mean maximum urinary flow rate was 10.2 ± 4.8 ml/s (range 4 to 15.8). There were no significant differences in age, prostate volume, IPSS score, uroflowmetry parameters, post-void residual urine volume and PdetQmax, Qmax on urodynamic study parameters. The only related factor with successful outcomes was Wmax ≥7 W/m2 (p<0.001) (Table 1).

The maximum Watts factor (Wmax≥7W/m2), an index for detrusor underactivity, is the only predicting factor affecting the successful outcomes after holmium laser enucleation of prostate in urodynamically equivocal men.

The maximum Watts factor (Wmax≥7W/m2) is the only predicting factor affecting the successful outcomes after holmium laser enucleation of prostate in urodynamically equivocal men.

van Venrooij GE, van Melick HH, Eckhardt MD, et al: Correlations of urodynamic changes with changes in symptoms and well-being after transurethral resection of the prostate. Urol 168: 605–609, 2002
Recommendations of the International Scientific Committee: Evaluation and treatment of lower urinary tract symptoms (LUTS) in older men, in Chatelain C, Denis L, Foo KT, et al (Eds): Benign Prostatic Hyperplasia: 5th International Consultation on Benign Prostatic Hyperplasia (BPH). Plymouth, UK, Plymbridge Distributors, 2001, pp 519–534.