Increased Optical Magnification From 2.5× to 4.3× With Technical Modification Lowers the Positive Margin Rate in Open Radical Retropubic Prostatectomy

Purpose: We compared the positive surgical margin rate of 2.5× and 4.3× optical loupe magnification with associated technical improvement during open radical retropubic prostatectomy. Materials and Methods: From January 2, 2004 to September 16, 2005, 511 consecutive patients underwent open radical retropubic prostatectomy, as performed by 1 surgeon. Because 10 patients refused authorization for a retrospective chart review, 501 were evaluable. For the first 265 patients 2.5× power loupes were used and for the subsequent 236 we used 4.3× power loupes. We used the chi-square test for univariate analysis, followed by multivariate logistic regression analysis adjusted for commonly recognized predictors of positive surgical margins in the 2 successive cohorts. Focusing on the apex, which was the most commonly reported site of positive surgical margins, we include operative video segments mimicking 4.3× magnification to demonstrate the surgical precision possible at 4.3× for managing the periurethral fascial bands of Walsh and urethral transection at the prostato-urethral junction. Results: Positive surgical margins were identified in 39 of 265 patients (14.7%) at 2.5× and in 12 of 236 (5.1%) at 4.3×. Apical positive surgical margins were identified in 25 of 265 patients (9.4%) at 2.5× and in 5 of 236 (2.1%) at 4.3×. On multivariate analysis 4.3× magnification was independently associated with a 75% decrease in the odds of a positive surgical margin overall and in the apex alone (p <0.001 and 0.003, respectively). Conclusions: This exploratory retrospective study suggests that, compared with 2.5× magnification, the use of 4.3× magnification with technical refinements that are not possible or deemed safe at 2.5× resulted in a substantial decrease in the positive surgical margin rate.