Nerve Grafting to Restore Erectile Function in Patients After Radical Prostatectomy
Prostate cancer is a very widespread disease affecting as many as 11% of men in the United States. This condition is frequently treated surgically by means of radical prostatectomy, when the whole prostate, seminal vesicles and part of the ureter are removed. In total, there are 90,000 RPs performed every year in the US alone. Up to 85% of men report suffering from erectile dysfunction after prostatectomy, so effective penile rehabilitation techniques for post-RP patients are highly sought after.
A new treatment protocol developed by a group of Australian microsurgeons and described in this 2019 European Urology article has a success rate of 71% at 12 months post-surgery. It aims to restore the normal function of nerves responsible for initiating penile erection, which often get damaged during radical prostatectomy. To do that, two grafts of the sural nerves are taken from the patient’s legs and placed into their thighs. One end of each graft is attached to the femoral nerve in the thigh. The other end is planted inside the corpora cavernosa of the penis. As new nerve fibers grow along the graft and into the cavernous body of the penis, the patient’s erectile function gets restored. The donor sural nerves are not necessary for the normal functioning of the leg, so their removal does not cause any unwanted effects apart from temporary quadriceps weakness that goes away within a week after surgery.
The new procedure is minimally invasive and, due to the use of autologous nerve graft, reduces the risk of adverse reactions. For comparison, other common means of treating post-prostatectomy erectile dysfunction frequently case side effects. Up to 50% of all patients using intracavernous alprostadil injections to treat ED report experiencing penile pain and up to 30% suffer from other side effects. The latter include priapism, corporeal fibrosis, bruising at the site of injection and urethral bleeding. Penile prosthesis surgery is another alternative treatment with a higher success rate of over 90%. However, it is more invasive and associated with a high incidence of post-operative infections of 8-20%.
Nerve grafting technology itself is not new – the first medical articles describing it date back to 1903. A number of studies released between 2006 and 2014 focused on the use of nerve grafts in post-RP patients showing varying efficacy between 28% and 71%. However, these earlier studies were based on different techniques of connecting the donor nerve grafts to the nerves in the penis. The new approach to the treatment – sural to femoral end-to-side nerve grafting – was first used to restore erectile function in 2017 by Dr. Fausto Viterbo from Brazil. Drs. Reese, Dangerfield, and Coombs improved the treatment further by inducing minor injury to the femoral nerve prior to attaching the sural nerve graft to it. This minor injury stimulates nerve regeneration and allows to reach the desired effect sooner.
There were 10 patients enrolled in the original study by Viterbo et al. 6 of these patients were able to engage in penetrative intercourse 13 months after surgery. The study by Reese, Dangerfield and Coombs included 17 patients, 12 of whom had their erectile function restored in full 1 year after surgery. The results of new clinical studies are expected to be released in 2019 and, as more data on the efficacy and safety of the new technology becomes available, we will see it used more widely to treat post-RP erectile dysfunction.
- Prostate cancer incidence statistics - https://www.cancer.org/cancer/prostate-cancer/about/key-statistics.html
- Number of radical prostatectomies per year in the United States - https://www.onclive.com/publications/obtn/2011/march-2011/robotic-assisted-laparoscopic-radical-prostatectomy-has-steep-learning-curve
- Prevalence of ED in post-prostatectomy patients - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5005072/
- JC Reese, DC Dangerfield, CJ Coombs, Nerve grafting to improve erectile function following radical prostatectomy - https://www.europeanurology.com/article/S0302-2838(19)30265-9/fulltext
- Incidence of side effects in patients with ED receiving intracavernous alprostadil injections - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1477601/
- Penile prosthesis surgery success rates - https://healthcare.utah.edu/urology/sexual-dysfunction/penile-implants/about-procedure.php
- Incidence of infection in patients undergoing penile prosthesis surgery - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2581729/
- Overview of studies focusing on nerve grafting to restore erectile function in post-RP patients, 2006 to 2014 - https://medicalpolicies.amerigroup.com/medicalpolicies/policies/mp_pw_a053390.htm
- F Viterbo et al, Using nerve grafting to improve erectile function in post-prostatectomy patients with ED - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5636474/