The Effect of the Vesical Adaptation Response to Diuresis on Lower Urinary Tract Symptoms after Robot-Assisted Laparoscopic Radical Prostatectomy: A Pilot Proof of Concept Study

BACKGROUND When urine output increases, voided volume at each voiding also increases in normal subjects. This is generally understood as a vesical adaptation response to diuresis (VARD). Because lower urinary tract symptoms (LUTS) are supposed to be improved by the change in bladder function after robot-assisted laparoscopic radical prostatectomy (RARP), the aim of the present study was to investigate whether VARD is involved in the improvement of LUTS after RARP. METHODS 100 consecutive patients who underwent RARP and had the International Prostate Symptom Score (IPSS), quality of life (QOL) index, a frequency-volume chart (FVC), uroflowmetry, and post-voided residual urine (PVR) available were evaluated before and after RARP. This cohort was divided into patients with and without preoperative LUTS according to the preoperative IPSS total score. VARD was defined as the presence of a significant correlation between the urine output rate and voided volume at each voiding (R2>0.2). RESULTS In patients with preoperative LUTS, the IPSS total, storage, and voiding symptom scores were significantly improved after RARP (all P<0.001). The QOL index was also significantly improved after RARP (P<0.05). Although VARD was not seen before RARP (R2 = 0.05), it was seen after RARP (3 months R2 = 0.22, 12 months R2 = 0.23). PVR was significantly reduced after RARP (P = 0.004). CONCLUSIONS Improvement of LUTS was seen with acquisition of VARD after RARP. As a result, urinary QOL was also improved in patients with preoperative LUTS. RARP might be an effective procedure for amelioration of LUTS by the acquisition of VARD.