Validation of 90-Day Percent Erection Fullness as a Predictor of Long-Term Potency Recovery after Robot-Assisted Radical Prostatectomy
Objective: To introduce a patient-reported percent erection fullness scale (% fullness) following robot-assisted radical prostatectomy (RARP) as a qualitative adjunct to the International Index of Erectile Function - 5 (IIEF-5) questionnaire and as a 90-day predictor of two-year potency outcomes.
Patients and Methods: Prospective data was collected from 540 men with normal preoperative sexual function (defined as an IIEF-5 score between 22 and 25) who underwent RARP by a single surgeon, of which 299 had complete data at all follow-up time points. In addition to standard assessment tools (IIEF-5 and erections sufficient for intercourse), patients were asked to “indicate the fullness you are able to achieve in erections compared to before surgery?” (0-10...100%). The primary outcome was prediction of potency (defined as ESI) at 24 months, based on 90-day % fullness tertiles (0-24%, 25-74%, and 75-100%).
Results: 299 men with complete follow-up were included in initial analysis. Significant predictors of 24 month potency included age, BMI, pathologic stage, nerve-sparing status, and % fullness tertiles. In multivariable analysis, % fullness demonstrated excellent prediction of 2-year potency recovery (R2=0.89) and internal validation suggests good discrimination (AUC = 0.83). Repeated analysis in the full patient cohort (n=540) yielded similar results.
Conclusions: We introduce % fullness as a qualitative adjunct to the IIEF-5 and as a 90-day predictor of two-year potency recovery post-RP. This initial report is hypothesis-generating such that the use of % fullness enables the identification of men most likely to benefit from early, secondary intervention.