MP57-17: The Collar technique for apical dissection during robot-assisted radical prostatectomy: updated series after five years from its introduction.

Angelo Mottaran*, Bologna, Italy, Carlo Andrea Bravi, Milan, Italy, Luca Sarchi, Modena, Italy, Pietro Piazza, Bologna, Italy, Fernando Gonzalez Meza, Marco Corsetti, Ghent, Belgium, Sophie Knipper, Hamburg, Germany, Marco Paciotti, Milan, Italy, Marco Amato, Modena, Italy, Rui Farinha, Ghent, Belgium, Stefano Puliatti, Modena, Italy, Simone Scarcella, Celine Sinatti, Ghent, Belgium, Geert De Naeyer, Ruben De Groote, Alexandre Mottrie, Aalst, Belgium

Introduction: Apical dissection is a challenging step during robot-assisted radical prostatectomy (RARP), and may affect the risk of positive surgical margins (PSM). For this delicate surgical step, we previously described the “Collar” technique that allowed us to lower the rate of PSM. After five years from its introduction, we want to update our series on this novel surgical technique.

Methods: A total of 1716 consecutive patients underwent RARP at OLV hospital (Aalst, Belgium) between 2010 and 2020. As of June 2015, the “Collar” technique was utilized during apical dissection, which included the incision of the urethral sphincter complex (USC) 2–3 mm distally to the apex; the underlying smooth muscle was exposed and incised closer to the apex to preserve the maximal length of the lissosphincter. Standard technique consisted in sharp and direct division of membranous urethra at the level of the urethra-prostatic junction without dissection of single components of the USC. Multivariable logistic regression tested the association between technique employed (standard vs. Collar technique) and risk of PSM and, in separate analysis, apical PSM, after adjusting for preoperative PSA level, pathologic grade, stage, and nodal status.

Results: A total of 1034 (60%) and 682 (40%) men received collar and standard technique, respectively. Despite higher rate of International Society of Urologic Pathology group was =3 at final pathology in the collar vs. standard technique group (39% vs. 32%; p=0.002), preoperative PSA, stage, and nodal status did not differ between the groups (all p=0.075). Overall, 269 (16%) patients had PSM, and 134/269 (50%) were apical PSM. There were no differences between the groups with respect to both PSM (17% vs. 15% in standard vs. collar technique group) and apical PSM (8% vs. 7% in standard vs. collar technique group; both p=0.3). After adjusting for confounders, patients receiving the collar technique had lower odds of overall PSM (odds ratio [OR]: 0.78; 95% confidence interval [CI]: 0.75, 0.82; p<0.0001). Similar results were found when apical PSM was the outcome of interest, with lower probability of apical PSM for men in the collar vs. standard technique group (OR: 0.82; 95%CI: 0.81, 0.82; p<0.0001).

Conclusions: The collar technique during apical dissection reduces the rates of both overall and apical positive surgical margins as compared to traditional surgical technique. Future investigations are warranted to confirm also functional results.

Source of Funding: None