Inflatable penile prosthesis implant length with baseline characteristic correlations: Preliminary analysis of the PROPPER study

Background: "Prospective Registry of Outcomes with Penile Prosthesis for Erectile Restoration" (PROPPER) is a large, multi-institutional, prospective clinical study to collect, analyze, and report realworld outcomes for men implanted with penile prosthetic devices. We prospectively correlated co-morbid conditions and demographic data with implanted penile prosthesis size to enable clinicians to better predict implanted penis size following penile implantation. We present many new data points for the first time in the literature and postulate that radical prostatectomy (RP) is negatively correlated with penile corporal length. Methods: Patient demographics, medical history, baseline characteristics and surgical details were compiled prospectively. Pearson correlation coefficient was generated for the correlation between demographic, etiology of ED, duration of ED, co-morbid conditions, pre-operative penile length (flaccid and stretched) and length of implanted penile prosthesis. Multivariate analysis was performed to define predictors of implanted prosthesis length. Results: From June 2011 to June 2017, 1,135 men underwent primary implantation of penile prosthesis at a total of 11 study sites. Malleable (Spectra), 2-piece Ambicor, and 3-piece AMS 700 CX/LGX were included in the analysis. The most common patient comorbidities were CV disease (26.1%), DM (11.1%), and PD (12.4%). Primary etiology of ED: RP (27.4%), DM (20.3%), CVD (18.0%), PD (10.3%), and Priapism (1.4%), others (22.6%). Mean duration of ED is 6.2±4.1 years. Implant length was weakly negatively correlated with White/Caucasian (r=-0.18; P < 0.01), history of RP (r=-0.13; P < 0.01), PD as comorbidity (r=-0.16; P < 0.01), venous leak (r=-0.08; P < 0.01), and presence of stress incontinence (r=-0.13; P < 0.01). Analyses showed weak positive correlations with Black/AA (r=0.32; P < 0.01), CV disease as primary ED etiology (r=0.08; P < 0.01) and pre-operative stretched penile length (r=0.18; P < 0.01). There is a moderate correlation with pre-operative flaccid penile length (r=0.30; P < 0.01). Conclusions: Implanted penile prosthesis length is negatively correlated with some ethnic groups, prostatectomy, and incontinence. Positive correlates include CV disease, preoperative stretched penile length, and flaccid penile length.