Results of January survey 2006

The most advisable method to favour the recovery of erectile function after nerve-sparing radical prostatectomy is:

1) early initiation of PGE1 injections: Percentage of answers: 37,1%
2) early initiation of vacuum device: Percentage of answers: 5,7%
3) early initiation of PDE5 inhibitors: Percentage of answers: 42,9%
4) simultaneous placement of a penile prosthesis at radical retropubic prostatectomy: Percentage of answers: 5,7%
5) either 1) or 2): Percentage of answers: 8,6%

Comments

Data is available showing that PGE1 may act on penile rehabilitation not only by relaxing corpora cavernosa and increasing blood flow and oxygenation, but also by stimulating the regeneration of local nerves, thereby increasing NO release (6-11). From a clinical viewpoint, early administration of PGE1 seems to facilitate the immediate recovery of spontaneous erection, both in NSRRP and NNSRRP, and (although further evidence is needed) improve the response to PDE5 inhibitors. (12-14)
The role of vacuum device in ED rehabilitation has not yet been demonstrated. Vacuum device + proximal constriction bend is an effective treatment of ED, but causes penile hypoxia and acidosis, and rather than promoting cavernosal relaxation and arterial inflow, induces erection by reducing external pressure. Clinical efficacy of vacuum in rehabilitation has been evaluated in a controlled study on 109 pts, with inconclusive results. (1-5)
Many responders preferred PDE5 inhibitors as a rehabilitative treatment, although the efficacy of PDE5 in improving erection in the early post-operative period is very questionable, as being impaired by nerves surgical trauma. Options 1, 2 and 5 have probably been selected by responders who share this perplexity. However, the daily administration of sildenafil bed-time has been shown to improve nocturnal erection (NPT) and decrease penile fibrosis after RP, and to improve recovery of spontaneous erection 1 year after bilateral NSRRP. (14-15) Actually, the mechanism through which early use of PDE5 inhibitors after RP could rehabilitate erectile function in the long-term has not been fully understood, but may include reduction in postoperative corpora hypoxia, enhanced endothelial function and possible neurotropic action.
Finally, simultaneous placement of penile prosthesis is a valid option, warranting a good postoperative QoL in patients who are not candidate to a nerve sparing procedure. (17)

References

1. Bosshardt RJ, Farwerk R, Sikora R, Sohn M, Jakse G. Objective measurement of the effectiveness, therapeutic success and dynamic mechanisms of the vacuum device. Br J Urol. 1995;75:786-791.

2. Broderick GA, McGahan JP, Stone AR, White RD. The hemodynamics of vacuum constriction erections: assessment by color Doppler ultrasound. J Urol. 1992;147:57-61.

3. Diederichs W, Kaula NF, Lue TF, Tanagho EA. The effect of subatmospheric pressure on the simian penis. J Urol. 1989;142:1087-1089.

4. Raina R, Agarwal A, Ausmundson S, et al. Early use of vacuum constriction device following radical prostatectomy facilitates early sexual activity and potentially earlier return of erectile function. Int J Impot Res. 2006;18:77-81.

5. Moon DG, Lee DS, Kim JJ. Altered contractile response of penis under hypoxia with metabolic acidosis. Int J Impot Res. 1999;11:265-271.

6. Snider WD, Zhou FQ, Zhong J, Markus A. Signaling the pathway to regeneration. Neuron. 2002;35:13-16.

7. Pearse DD, Pereira FC, Marcillo AE, et al. cAMP and Schwann cells promote axonal growth and functional recovery after spinal cord injury. Nat Med. 2004;10:610-616.

8. Chierzi S, Ratto GM, Verma P, Fawcett JW. The ability of axons to regenerate their growth cones depends on axonal type and age, and is regulated by calcium, cAMP and ERK. Eur J Neurosci. 2005;21:2051-2062.

9. Cai D, Qiu J, Cao Z, McAtee M, Bregman BS, Filbin MT. Neuronal cyclic AMP controls the developmental loss in ability of axons to regenerate. J Neurosci. 2001;21:4731-4739.

10. Kogawa S, Yasuda H, Terada M, Maeda K, Kikkawa R. Apoptosis and impaired axonal regeneration of sensory neurons after nerve crush in diabetic rats. Neuroreport. 2000;11:663-637.

11. Padmanaban P, McCullough AR. The effect of prostaglandin E-1 (PGE-1) urethral suppository (MUSE) and injections on corporal oxygen saturation (StO2) in men with erectile dysfunction (ED). J Androl. In press.

12. Montorsi F, Guazzoni G, Strambi LF, et al. Recovery of spontaneous erectile function after nerve-sparing radical retropubic prostatectomy with and without early intracavernous injections of alprostadil: results of a prospective, randomized trial. J Urol. 1997;158:1408-1410.

13. Gontero P, Fontana F, Bagnasacco A, et al. Is there an optimal time for intracavernous prostaglandin E1 rehabilitation following nonnerve sparing radical prostatectomy? Results from a hemodynamic prospective study. J Urol. 2003;169:2166-2169.

14. Mulhall JP, Land S, Parker M, Waters B, Flanigan RC. The use of an erectogenic pharmacotherapy regimen following radical prostatectomy improves recovery of spontaneous erectile function. J Sex Med. 2005;2:532-542.

15. Schwartz EJ, Wong P, Graydon RJ. Sildenafil preserves intracorporeal smooth muscle after radical retropubic prostatectomy. J Urol. 2004;171:771-774.

16. Padma-Nathan H, McCullough A, Guiliano F, Toler S, Wohlhuter C, Shlipsky A. Postoperative nightly administration of sildenafil citrate significantly improves normal spontaneous erectile function after bilateral nerve-sparing radical prostatectomy. J Urol. 2003;169(suppl4):375.

17. Ramsawh HJ, Morgentaler A, Covino N, Barlow DH, DeWolf WC Quality of life following simultaneous placement of penile prosthesis with radical prostatectomy J Urol. 2005 Oct;174(4 Pt 1):1395-8.