IMPACT OF NERVE SPARING ON POSTOPERATIVE CONTINENCE FOLLOWING ROBOT ASSISTED RADICAL PROSTATECTOMY: A PROPENSITY SCORE MATCHED STUDY

INTRODUCTION & OBJECTIVES: We evaluated the impact of nerve sparing during robot assisted radical prostatectomy (RARP) on postoperative continence outcomes in a single surgeon, single centre propensity score matched study. MATERIAL & METHODS: The study population consisted of 2362 patients who underwent RARP for localized prostate cancer by a single surgeon (VP) from January 2008 through May 2014. A query of our Institutional Review Board approved registry identified 92 men with nonnerve sparing (NNS, group 1) RARP who were computer-matched in a 1:1 ratio to 92 patients with complete nerve sparing (CNS: bilateral full nerve sparing, group 2) RARP and 92 patients with partial nerve sparing (PNS: unilateral full nerve sparing with or without contralateral partial nerve sparing and bilateral partial nerve sparing, group 3) RARP using a propensity score matched algorithm. Perioperative and postoperative functional outcomes for three groups were compared. Degree of nerve sparing (NS) was graded intra-operatively by the surgeon independently at either side as complete, partial or none. Postoperative continence was defined as using no pads per day. Followup data were collected at 6 weeks, 3, 6, 9, and 12 months to assess functional outcomes. RESULTS: When NNS group was compared with PNS group, all pre-operative clinical characteristics ,intraoperative and pathological parameters were comparable.At 3 months,the continence rate was significantly higher and mean time to continence was significantly lower in PNS group in comparison to NNS group(91.3% vs 72.1% respectively,p=0.01 and 2.19 months vs 3.91 months,p=0.03 ). However,on comparing CNS group with NNS group,NNS group has significantly higher clinical stage(p=0.03),D’Amico risk classification(p=0.04) and extraprostatic extension(p=0.03). However,at 3 months,the continence rate was significantly higher and mean time to continence was significantly lower in CNS group in comparison to NNS group(92.2% vs 72.1% respectively,p=0.01 and 2.03 months vs 3.91 months respectively,p=0.02 ). However, the continence rate was comparable in 3 groups at 1 year (94.1%, 92.7% and 84.7% respectively in CNS, PNS and NNS groups p =0.43). CONCLUSIONS: Neurovascular bundles(NVB) preservation (irrespective of complete or partial) during robot assisted radical prostatectomy results in an earlier return of postoperative urinary continence .A significantly higher number of patients achieve urinary continence between 0-3 months after surgery ,in comparison to propensity matched patients with non-nerve sparing procedure .Beyond 3 months post-surgery ,there was no difference in ability to achieve urinary continence regardless of NVB preservation status.