V2160: Intraoperative Neurovascular structure-adjacent frozen-section examination (NeuroSAFE) increases nerve-sparing frequency and reduces positive surgical margins in DaVinci-robot-assisted laparoscopic radical prostatectomy (DVP): experience after 1157 consecutive patients

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Introduction and Objectives
The clinical and oncological benefit of intraoperative frozen sections covering the entire contact area of the prostate and the right and left neurovascular bundle (NeuroSAFE) in open radical prostatectomy has been described earlier. However in DVP this approach is often avoided due to suspected difficulties in harvesting the prostate during the procedure, loss in pneumoperitoneum, increased blood loss and lacking impact on functional outcome.

In this study, we demonstrate the technique, feasability and beneficial impact of our NeuroSAFE technique on the rate of nerve-sparing (NS) in DVP and analyze the oncological outcome.

Methods
We analyzed 1157 consecutive patients who underwent DVP from 2004 to 2012. NeuroSAFE was performed in 786 patients.

Specimen harvesting: DVP was performed in a descending technique. After separation of the prostate from the sphincter, the camera trocar was disconnected from the camera arm. The specimen was removed via the camera trocar incision by extending the incision according to the size of the prostate. All other arms stay connected. To avoid blood spillage from the dorsal vein complex, one robotic arm maintained upward traction on the transurethral catheter. Pneumoperitoneum was reestablished by suturing the widened trocar site and replacement of the optical trocar.

NeuroSAFE was performed on the whole latero-rectal surface of the prostate corresponding to the area of the preserved neurovascular bundles.

We analyzed OR-time, blood loss and the rate of NS in men with vs. without NeuroSAFE. A propensity score based analysis was performed with the postoperative clinico-pathological variables (pT-stage, pN, Gleason score, PSA and year of surgery).

Results
There was no significant difference in blood loss (253±220 ml vs. 259±267 ml, p=0.99) and OR-time in NeuroSAFE vs. non-NeuroSAFE (224 min ±48.0 vs. 221 min ±67.5 p=0.276).

The rate of NS in DVP was significantly higher with NeuroSAFE (overall 94% vs. 76%, pT2 97% vs. 86%, pT3a 90% vs. 74%, pT3b 89% vs. 32%). The rate of positive surgical margins was lower in men with >pT3a-PCa and NeuroSAFE (overall 19% vs. 25%, T3a 15% vs. 41%, T3b 41% vs. 61%).

Conclusions
Intraoperative frozen section using the NeuroSAFE-technique in DVP is a rapid and feasible procedure without compromising OR-time and oncological outcome. We recommend performing our NeuroSAFE technique in all DVPs with intended nerve-sparing.

Funding: none