Impact of prostatic shape on the difficulty of robot-assisted laparoscopic radical prostatectomy

Background: To investigate the impact of prostatic shape observed on preoperative magnetic resonance imaging (MRI) on the difficulty of robot-assisted laparoscopic radical prostatectomy (RALP). Methods: We retrospectively reviewed the operative records of 211 patients who underwent RALP. We excluded patients who received neoadjuvant therapy. All surgeries in this study were performed by two surgeons. Each patient clinicopathological and surgical data were reviewed. Prostate sphericity was evaluated by measuring the roundness of the prostate at the largest axial slice by MRI. The console time was adopted as an objective indicator for assessing surgical difficulty. Results: The mean prostate volume was 34 cc (range 14 to 88) and the mean prostate roundness was 0.55 (range 0.24 to 0.90). The mean console time was 194 minutes (range 95 to 296). To assess the relationship between prostate volume and console time, scatter plot analysis was performed. The prostate volume had a weak positive correlation with the console time (r =0.165, p=0.016). Similarly, scatter plot analysis between the prostate roundness and console time demonstrated a weak positive correlation (r =0.167, p=0.015) . Next, we performed subgroup analysis of 56 patients with a large prostate volume (≥ 40 cc), and the positive correlation between the prostate volume and the console time disappeared (r =0.142, p=0.296). On the other hand, the prostate roundness was more strongly correlated with the console time (r =0.439, p=0.001). Conclusions: Our results indicated that the spherical shape of the prostate is associated with the surgical difficulty of RALP, especially in patients with a large prostate volume.