Long-term change in measured penile length after primary inflatable penile prosthesis without a standardized postoperative cycling protocol: an opportunistically ascertained single-surgeon cohort of 223 returning patients

INTRODUCTION: Long-term penile length data after inflatable penile prosthesis placement derive largely from small rehabilitation series. We evaluated long-term change in measured penile length and transverse width, potential predictors, and device use after primary implantation without a prescribed rehabilitation protocol. METHODS: This retrospective cohort analysis included 223 returning patients with a preoperative stretched-flaccid length, a fully inflated intraoperative placement-time length, and a fully inflated office length recorded at least 24 months after primary implantation. The primary outcome was the within-state placement-to-follow-up difference. Secondary analyses included the mixed-state difference from preoperative stretched-flaccid length, tape-measured mid-shaft width, exploratory predictors, device use, and prespecified subgroups. RESULTS: The mean follow-up was 49.0 months and the mean age was 74.2 years. Long-term fully inflated length exceeded the fully inflated placement-time length by 1.28 cm (95% CI, 1.12-1.45; P < .0001). Using a pragmatic 0.5-cm descriptive threshold, 70.0% increased, 25.6% were stable, and 4.5% decreased. The 2.04-cm difference from preoperative stretched-flaccid length mixed different measurement states and was not interpreted as biological gain. Mean tape-measured mid-shaft width changed by 0.13 cm (95% CI, 0.08-0.17), but the method did not support mechanistic inference. In the complete 2021-2023 operative registry, 160 of 628 eligible implants (25.5%) were represented. Of 223 patients, 213 (95.5%) reported sexual activity at follow-up. CONCLUSIONS: Among patients who returned for long-term care, the measured fully inflated penile length was greater than the intraoperative placement-time value. The opportunistic and uncontrolled design, incomplete capture, rater-timepoint confounding, measurement limitations, and device-state differences preclude causal or mechanistic conclusions. These findings do not support prosthesis placement as a cosmetic lengthening procedure or use of the exploratory predictor for clinical decisions.