**4.1 Erectile function after radical prostatectomy**

Generally, the potency rate is aggravated by injury to NVB after radical prostatectomy. Poel *et al.* reported a potency rate 53.3 %at 6 months after RALP, and 42% of patients had potency without using a PDE5 inhibitor. They concluded that prostatic fascia preservation resulted to good potency rates after RALP.18 Consequently, preservation of NVB and prostatic fascia is important to preserve erectile function. Di Pierro *et al.* compared potency rates between groups of patients treated with RRP and RALP. They performed RALP with a procedure using a transperitoneal approach and preserved the NVB through a tension- and energyfree technique19 as far as cancer localization allowed, and reported that the potency rate without PDE-5 inhibitors of the RALP group (68% and 55%) was significantly higher than that of the RRP group (25% and 26%) at 3 and 12 months after RALP.15
