Short-term stretched penile length analysis for subsequent erectile dysfunction after robotic-assisted radical prostatectomy with bilateral neurovascular bundle preservation

Introduction Stretched Penile Length (SPL) is observed to shrink after radical prostatectomy (RP) and has chances resuming the length as long as 12 months. Objective To assess the short-term SPL change from patients after robotic-assisted radical prostatectomy (RARP) with bilateral neurovascular bundle (NVB) preservation and experiencing subsequent erectile dysfunction (ED). Effects from tadalafil, post-operative androgen deprivation therapy (ADT), and no medication or intervention are compared. Methods From April to December 2018, patients developing ED (IIEF-5<22) after RARP with bilateral NVB preservation were included. SPL was measured as length from pubic symphysis to external urethral opening. Tadalafil 5 mg once daily (Group 1), postoperative ADT (Group 2) and control group (Group 3) were classified. Postoperative ADT was prescribed during the whole periods of 6 months for surgical adverse effects in group 2. Follow-ups were arranged 2 weeks after operation in the first time, and then every month up to 6 months. Student t test, chi-square test and SAS 9.4 were utilized to see if significant difference when p<0.05. Results With 64 men, 1 was excluded for preoperative ADT use. SPL-related comparisons were listed at Table 1. Preoperative SPL was measured without differences. Generally, in 6-month span, more men were with increased SPL in group 1 than in group 3, and also more with deterioration compared to group 3 (p=0.048). Same trend was observed in group 2 compared to group 3 (p=0.036). Men in group 1 (at the time deciding to take tadalafil) experienced a worse shortening SPL than group 3 (the 30–day change after operation) (p< 0.0001). Significantly improvement on SPL between before (7.93±1.89 (median: 7.5) cm) and after (8.59±2.17 (median:9) cm) tadalafil in group 1 (p=0.037) and also significantly improved against the SPL change from post-operative 30-day to 5-month of group 3 (p=0.004). Conclusions In our analysis, 63.7% of subsequent ED after RARP with bilateral NVB preservation would experience SPL shortening around 3 cm (around 30% of preoperative SPL) if only observation in 6 months after operation. Postoperative ADT for 6 months would contribute to approximately additional 15% shortening rates with the same degree. Significant improvement around 1 cm (around 10% of the preoperative SPL) on SPL was observed after tadalafil 5 mg once daily with median 4-month prescription. Disclosure Work supported by industry: no.