Postoperative Bladder Neck to Pubic Symphysis Ratio Predictive for De Novo Overactive Bladder after Robot-Assisted Radical Prostatectomy

Nayuka Matsuyama; Taku Naiki; Shuzo Hamamoto; Yosuke Sugiyama; Yasue Kubota; Takashi Hamakawa; Toshiki Etani; Shoichiro Iwatsuki; Kazumi Taguchi; Yuya Ota; Masakazu Gonda; Maria Aoki; Toshiharu Morikawa; Taiki Kato; Atsushi Okada; Takahiro Yasui

doi:10.3390/diagnostics13203173

Postoperative Bladder Neck to Pubic Symphysis Ratio Predictive for De Novo Overactive Bladder after Robot-Assisted Radical Prostatectomy

Diagnostics (Basel). 2023 Oct 11;13(20):3173. doi: 10.3390/diagnostics13203173.

Authors

Affiliations

¹ Department of Nephro-Urology, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan.
² Department of Pharmacy, Nagoya City University Hospital, Nagoya 467-8601, Japan.
³ Department of Clinical Physiology, Graduate School of Nursing, Nagoya City University, Nagoya 467-8601, Japan.
⁴ Department of Urology, Nagoya City University West Medical Center, Nagoya 462-8508, Japan.
⁵ Department of Urology, Nagoya City University East Medical Center, Nagoya 464-8547, Japan.

Abstract

Background: The aim was to investigate the incidence and clinical predictive factors of de novo overactive bladder (OAB) after robot-assisted radical prostatectomy (RARP), including a Retzius-sparing (RS) approach, in the same period at a single institution.

Methods: Of a total of 113 patients with localized prostate cancer, 81 received conventional RARP (CON-RARP) and 32 received RS-RARP at our institution. The basic characteristics data of patients and self-assessment questionnaires, including IPSS and OABSS, were obtained preoperatively and 1, 3, and 6 months after RARP. In addition, a retrospective biomarker analysis was also performed of predictive clinical parameters obtained from cystography that included a postoperative bladder neck to pubic symphysis (BNPS) ratio.

Results: Patients' basic characteristics were similar between CON-RARP and RS-RARP groups. With respect to the surgical procedure, anastomosing time was found to be significantly longer for patients in the RS-RARP compared to the CON-RARP group (p < 0.01). Compared to the CON-RARP group, the RS-RARP group showed a significantly lower postoperative BNPS and aspect ratio (p < 0.001). The incidence of de novo OAB in patients of the CON-RARP group was greater than for those in the RS-RARP group (40.7% CON-RARP vs. 25.0% RS-RARP), though this was not significant. Regarding the emergence of de novo OAB, the following were revealed in univariate analysis to be independent prognostic factors: age > 64 years (hazards ratio [HR]: 4.32, 95% confidence interval [CI]: 1.51-12.3), postoperative BNPS ratio > 0.44 (HR: 8.7, 95% CI: 6.43-54.5), postoperative aspect ratio > 1.18 (HR: 3.36, 95% CI: 1.49-7.61). Additionally, multivariate analysis identified a sole significant prognostic factor: postoperative BNPS ratio > 0.44 (HR: 13.3, 95% CI: 4.33-41.1).

Conclusion: Our findings indicate that the postoperative BNPS ratio may be a practical predictive indicator of the emergence of de novo OAB after RARP.

Keywords: Retzius sparing; de novo overactive bladder; postoperative bladder neck to pubic symphysis ratio.

Grants and funding

This research received no external funding.