Surgical Technique to Minimize Positive Margins During Nerve Sparing Robotic Prostatectomy

Jason D Engel¹, Arnold Schwartz*², Carter Le¹, Harold Frazier^1
1George Washington University, Washington, DC;²George Washington University, Chevy Chase, MD

Introduction:
The positive margin rate for robotic prostatectomy has in most large series been inordinately high. We describe an anatomically correct, non-intuitive dissection plane that ensures maximal capsular preservation. This has led to a positive margin rate in our series of 7%, a reduction from 29% before our dissection plane modification.
Methods:
103 consecutive robotic prostatectomies were reviewed. At case 64, we changed our plane of dissection while maintaining a nerve sparing technique in all cases. (Presentation will include video)
Results:
A reduction in positive margin rate from 29.7% to 7.7% was realized. (p=.007)

Demographics	Before change of dissection plane	After change of dissection plane	p-value
Number of patients	64	39
Mean age	59.77	58.75	0.459935
Mean Pre-op PSA	6.3157	5.9123	0.527986
Mean Pre-op Gleason Score	6.2969	6.475	0.224468
Mean Post-op Gleason score	6.4483	6.6757	0.176089
Gleason 6 and under	40	22	0.638519
Gleason 3+4	19	11	0.873936
Gleason 4+3	5	3	0.982579
Gleason 8 and over	2	4	0.13656
Mean Pct gland involvement	15.7407	18.2813	0.398695
Positive Margins (%)	0.296875	0.076923	0.007009

Conclusions:
The criticism of robotic prostatectomy that the rate of margin positivity is unacceptably high holds merit. Extreme care must be taken not to follow the natural dissection plane presented to the surgeon during the antegrade robotic approach. We have realized that there are two layers of fascia enveloping the prostate. With disciplined dissection that keeps the surgeon between these two layers, negative margins can be consistently achieved in nearly all cases without the need for nerve sacrifice. The technique we describe therefore may hold promise for allowing the robotic surgeon to achieve oncologic results comparable or better to even the most impressive open surgical series.

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