The Risks and Benefits of Cavernous Neurovascular Bundle Sparing during Radical Prostatectomy: A Systematic Review and Meta-Analysis

Purpose: We summarize published data on associations between cavernous neurovascular bundle preservation (nerve sparing) during prostatectomy and positive surgical margins, erectile function, urinary function and other patient reported outcomes. Materials and Methods: A systematic literature search of MEDLINE (R), Embase (R) and Cochrane Reviews databases was performed for interventional or observational studies published between 2000 and 2014. English language articles that compared clinical outcomes of patients undergoing nerve sparing and nonnerve sparing radical prostatectomy were included. Meta-analyses were performed to calculate pooled relative risk estimates for positive surgical margins, erectile dysfunction and urinary incontinence in nerve sparing and nonnerve sparing groups. Sensitivity analyses compared outcomes among unilateral and bilateral nerve sparing vs nonnerve sparing groups. Results: Of the 1,883 articles identified, 124 studies (73,448 patients) were included in the analysis. Nerve sparing did not increase the risk of positive surgical margins in patients with pT2 (RR 0.92, 95% CI 0.75-1.13) or pT3 disease (RR 0.83, 95% CI 0.71-0.96), potentially due to appropriate patient selection. The risk of incontinence was lower in nerve sparing cases (RR 0.75, 95% CI 0.65-0.85 and RR 0.61, 95% CI 0.44-0.84) at 3 and 12 months, respectively. The relative risk of erectile dysfunction with nerve sparing was 0.77 (95% CI 0.70-0.85) at 3 months and 0.53 (95% CI 0.39-0.71) at 12 months. Subgroup analyses of unilateral and bilateral nerve sparing approaches demonstrated similar results. Conclusions: Among cohort studies nerve sparing was not associated with worse cancer outcomes. Nerve sparing is associated with better urinary and erectile function. These results should be interpreted with caution given the potential for selection bias and unadjusted confounding factors.