Is there any difference in urinary continence between bilateral and unilateral nerve sparing during radical prostatectomy? A systematic review and meta-analysis

Context In men with prostate cancer, urinary incontinence is one of the most common long-term side effects of radical prostatectomy (RP). The recovery of urinary continence in patients is positively influenced by preserving the integrity of the neurovascular bundles (NVBs). However, it is still unclear if bilateral nerve sparing (BNS) is superior to unilateral nerve sparing (UNS) in terms of post-RP urinary continence. The aim of this study is to systematically compare the differences in post-RP urinary continence outcomes between BNS and UNS. Methods The electronic databases of PubMed and Web of Science were comprehensively searched. The search period was up to May 31, 2023. English language articles comparing urinary continence outcomes of patients undergoing BNS and UNS radical prostatectomy were included. Meta-analyses were performed to calculate pooled relative risk (RR) estimates with 95% confidence intervals for urinary continence in BNS and UNS groups at selected follow-up intervals using a random-effects model. Sensitivity analyses were performed in prospective studies and robotic-assisted RP studies. Results A meta-analysis was conducted using data from 26,961 participants in fifty-seven studies. A meta-analysis demonstrated that BNS improved the urinary continence rate compared to UNS at all selected follow-up points. RRs were 1.36 (1.14-1.63; p = 0.0007) at <= 1.5 months (mo), 1.28 (1.08-1.51; p = 0.005) at 3-4 mo, 1.12 (1.03-1.22; p = 0.01) at 6 mo, 1.08 (1.05-1.12; p < 0.00001) at 12 mo, and 1.07 (1.00-1.13; p = 0.03) at >= 24 mo, respectively. With the extension of the follow-up time, RRs decreased from 1.36 to 1.07, showing a gradual downward trend. Pooled estimates were largely heterogeneous. Similar findings were obtained through sensitivity analyses of prospective studies and robotic-assisted RP studies. Conclusion The findings of this meta-analysis demonstrate that BNS yields superior outcomes in terms of urinary continence compared to UNS, with these advantages being sustained for a minimum duration of 24 months. It may be due to the real effect of saving the nerves involved. Future high-quality studies are needed to confirm these findings.