A Matched and Controlled Longitudinal Cohort Study of Dehydrated Human Amniotic Membrane Allograft Sheet Used as a Wraparound Nerve Bundles in Robotic-Assisted Laparoscopic Radical Prostatectomy – Beyond the Abstract

Approximately 29,000 men die from prostate cancer each year in the United States. When diagnosed in the early organ-confined stage, there are multiple options for treatment depending on patient characteristics and preferences, including brachytherapy, external beam radiation therapy, or surgery. Robotic-assisted laparoscopic radical prostatectomy (RALP) has become the preferred modality of surgical treatment by most practicing urologists due to improved dexterity and visualization with equivalent oncologic and functional outcomes when compared with open prostatectomy.
During RALP, there are various steps that can potentially damage or traumatize the cavernosal nerves, causing compromised potency levels postoperatively. Intraoperative stretch injury, neuropraxia, thermal damage, lateral traction on nerves, etc. are all known to contribute to decreased potency postoperatively. Interestingly, sixty-eight percent of sexually active men without prostate cancer were willing to trade in 10 % of their lifespan if it gave them the pre-operative degree of sexual potency post procedure. It then behooves the surgeon to do his or her part to make a concerted effort in minimizing any and all factors which could potentially damage these delicate nerves intraoperatively, as well as adopt techniques which could potentially mitigate the effects of inadvertent trauma.

We came across reports in other fields, especially neurosurgery, where surgeons used dehydrated amniotic membrane (dHAM) wrapped around nerves for improved regeneration after trauma. An additional search revealed that these membranes have been used in a variety of treatment protocols for burns, orthopedic surgeries, eye surgery and even venous stasis ulcers. dHAM is a mechanically robust composite of biologically active amniotic tissue membrane derived naturally from the consensually donated human placenta of screened and tested women obtained during C-section. It has been proven to be safe for human use. Within urology, nerve growth factors and amniotic membrane wraps have been used in rats that had their cavernosal nerves severed during radical pelvic surgery, with improved electrically stimulated erections and mating behavior.

Figure 1
UroToday Individual and Single dHAM wraps for NVB
A. Single dHAM wrap for NVB   B. Individual dHAM wraps for NVB

Inspired by the abundance of data showing improved healing and nerve function with dHAM, we envisaged extrapolating this effect of dHAM to human cavernosal nerve recovery as early as 2011-2012 in a pilot study. Specifically, we used dHAM as a nerve wrap, placing the sheet around the composite of cavernosal nerve bundles during RALP. Initial work required countless hours spent in trying to determine the optimal technique, timing, and mode of delivery of dHAM to the sensitive area. Once we were able to perfect the technique and its reproducibility we were encouraged by the outcomes and reported our results to the international urological community. We then became the first in the world to use and report dHAM during RALP for early return of erectile function, with our early study winning Best Original Research at the 2014 World Congress of Endourology in Taipei, Taiwan.

Since our initial studies we have been able to accrue a large number of patients, and our current publication continues to demonstrate and ratify the improved rates of erectile function post RALP as objectively manifested as time until first erection and quantal changes in potency at 3 monthly intervals until 1 year post surgery using the Sexual Health Inventory for Men (SHIM) questionnaire score. To the best of our knowledge, this is the largest study published to date on the effect of dHAM as an effective adjunct to improved potency after RALP.

It is our hope that our research continues to spur further work on the potential benefits of dHAM in accelerating cavernosal nerve healing, and consequently, the onset of erectile function post RALP.

Written by: Sanjay Razdan, M.D.,MCh. Professor and Chairman, International Robotic Prostatectomy Institute, Director, Urology Center of Excellence, Director, Robotic Urology, MiVIP Center of Miami, Director, Robotic Prostate Program, Kendall Regional Medical Center, Director, Endourology, Robotic Fellowship Program, Larkins University Hospital, Miami, FL.
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