Hypothesis / aims of study
Robot-assisted radical prostatectomy (RARP) using the da Vinci surgical system has become the standard procedure for localized prostate cancer. RARP is considered a minimally invasive technique with a low complication rate, low transfusion rate, and short hospital stay. Unfortunately, however, a certain number of patients had a reduced quality of life (QOL) due to postoperative urinary incontinence. Various factors were reported to influence urinary incontinence RARP. In addition, techniques such as nerve sparing, bladder neck preservation, Retzius sparing, and the Hood technique have been devised for achievement of urinary continence. Advanced Reconstruction of Vesicourethral Support (ARVUS) is a technique reported in 2017 for achievement of urinary continence [1]. We had performed ARVUS in patients undergoing non-nerve-sparing RARP from 2019. The purpose of this study is to evaluate the effect of ARVUS on postoperative urinary continence in non-nerve-sparing RARP.
Study design, materials and methods
Patients who underwent non-nerve-sparing RARP between October 2010 and December 2020 at our department for prostate cancer (stages cT1–cT3 N0 M0) were included in the present study. All patients consented after being fully informed in accordance with the ethics committee at our institution. All study data were analyzed retrospectively. Age, BMI, prostate-specific antigen (PSA), prostate volume (PV), membranous urethral length (MUL), Gleason score (GS), clinical stage were recorded. Cystography was performed to measure the distance from the symphysis pubis to the bladder neck and the posterior urethrovesical angle. IPSS, ICIQ-SF, QOL index, and number of pads used each day were evaluated before RARP and at 1, 3, 6, and 12 months after RARP. Data are presented as median value and interquartile range (IQR). To exclude possible influences on urinary continence after RARP other than ARVUS, 1:1 propensity score matching was conducted. Propensity scores were estimated by multivariable logistic regression using variables such as age, clinical stage, BMI, PV, and MUL. Demographic factors were evaluated using the Mann-Whitney U test, chi-square test. To identify factors associated with urinary continence using the PICOMB definition at 12 months postoperatively, multivariable logistic regression analysis was performed [2]. Values of p<0.05 were considered significant. Statistical analyses were performed using EZR, which is a modified version of R Commander.
Results
In Table 1 patients’ characteristics are presented. The number of patients in non-ARVUS group was 41 and ARVUS group was 41. Median age, BMI, PV, and MUL for the ARVUS and non-ARVUS groups were 70.5 and 69 years, 23.2 and 24.1 kg/m², 24.2 and 26.6 ml, and 12.5 and13.8 mm, respectively. The distance from the symphysis pubis to the bladder neck at cystography was significantly shorter in the ARVUS group (median 10.9 mm vs. 17.6 mm, p<0.001) and the posterior urethrovesical angle was significantly smaller in the AUVUS group (median 129.6 degrees vs. 145 degrees, p<0.001). Table 2 showed ICIQ-SF total score, question 1, 2, 3, IPSS total score, and QOL index between two groups. In the ICIQ-SF, questions 1, 2, 3, and total scores were not significantly different at 1 and 3 months postoperatively, but the ARVUS group was significantly better at 6 and 12 months postoperatively. In terms of IPSS, the ARVUS group was significantly better than the non-ARVUS group after 3 months postoperatively. The QOL index was significantly better in the ARVUS group than in the non-ARVUS group at 6 months postoperatively, but there were no significant differences at other time points. Pad free rates were 9.1% and 6.8% in the non-ARVUS and ARVUS groups at 1 month, 20.5% and 15.9% at 3 months, 36.4% and 34.1% at 6 months, and 45.5% and 61.4% at 12 months postoperatively. In a multivariable logistic regression analysis with age, BMI, PV, MUL, and ARVUS performed as factors, MUL and ARVUS were significant factors in achieving PICOMB definition at 12 months postoperatively.
Interpretation of results
In the present study, postoperative urinary continence and QOL were both better with ARVUS group. The mechanism of ARVUS is to reinforce the vesicourethral anastomosis in a hammock-like shape, which is similar to the mechanism after urethral sling surgery, and is useful against urinary incontinence. In our study, postoperative cystography showed that the posterior urethrovesical angle in the ARVUS group was more sharply angled than in the non-ARVUS group. This was thought to be due to dorsal support of the urethra. In addition, for the evaluation of urinary continence, International Continence Society (ICS) recommended pad weight, not pad count, for the assessment of postoperative urinary incontinence after radical prostatectomy. The International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF) was developed as an international common questionnaire for the assessment of urinary incontinence symptoms and QOL [3]. In our study, there was no difference in pad free rate between the ARVUS and non-ARVUS groups, but the ARVUS group was significantly better in terms of urinary continence on the ICIQ-SF, suggesting that it is difficult to evaluate urinary incontinence by the number of pads used.