Is there an optimal time for intracavernous prostaglandin E1 rehabilitation following nonnerve sparing radical prostatectomy? Results from a hemodynamic prospective study

PURPOSE: Previous studies have shown that early intracavernous prostaglandin E1 injection may reduce significantly the incidence of veno-occlusive dysfunction before spontaneous erections recover after nerve sparing radical prostatectomy. We identify the more convenient postoperative timing for successful intracavernous injection rehabilitation in a series of patients who underwent nonnerve sparing radical prostatectomy. MATERIALS AND METHODS: A total of 73 patients with a normal preoperative International Index of Erectile Function score were randomly allocated to undergo dynamic color Doppler ultrasound study 20 mg. prostaglandin E1 at 1, 2 to 3, 4 to 6 and 7 to 12 months postoperatively, respectively. In all cases the peak systolic velocity, end diastolic velocity and resistance index were evaluated at 5, 10 and 20 minutes after injection. RESULTS: Of the patients 36 received the intracavernous injection within the first 3 months (group 1) and 37 received it at 4 to 12 months (group 2). A significantly higher proportion of group 1 patients had grade 3 erection compared with group 2. Peak systolic velocity less than 30 cm. per second in at least 1 cavernosal artery was recorded in 22.2% of group 1 patients and 51.3% of group 2 (p >0.05). CONCLUSIONS: Intracavernous injections after nonnerve sparing radical prostatectomy produce valid erectile responses in a significantly higher proportion of patients when started within month 3 after the operation. Injection given in postoperative month 1 gives the best response rate but with significant complications and poor patient compliance. Arteriogenic and venogenic factors seem to be involved with failure.