Is there a correlation between the outcome of transurethral resection of prostate and preoperative degree of bladder outlet obstruction?

To compare the impact of transurethral resection of prostate (TURP) on symptom scores and maximal flow rates (Qmax) in patients with equivocal bladder outlet obstruction (BOO) and definite BOO and to assess the relationship between the surgical outcomes and degree of preoperative BOO, we prospectively evaluated men with lower urinary tract symptoms and bladder outlet obstruction index (BOOI) greater than 20, who were refractory to conventional medical treatment and underwent TURP. Urodynamic evaluation, International Prostate Symptom Score (IPSS), uroflowmetry, post-void residual volume (PVR) check and transrectal ultrasound were performed. 20<BOOI<40 was defined as equivocal BOO and BOOI≥40 as definite BOO. Changes of IPSS, Qmax, PVR and correlation analysis was performed between the degree of improvement of Qmax, subdomains of IPSS and BOOI. Fifty-four patients showed equivocal BOO and 80 patients showed definite BOO. Preoperatively equivocal BOO group and definite BOO group showed significant differences in maximal bladder capacity and prevalence of detrusor overactivity, whereas no difference was noted in prostate volume. Postoperatively both groups showed improvements in Qmax, obstructive (IPSSO) and irritative (IPSSI) subdomain of IPSS, but the degree of improvement in Qmax and IPSSI subdomain was statistically significantly greater in definite BOO group. The degree of improvement of Qmax and IPSSI showed weak correlation with preoperative BOOI. As a weak correlation was identified between preoperative degree of BOO and outcome of TURP, other factors other than BOOI such as severity of patients' symptoms should be considered in deciding treatment modality.