Protective patch linked to erectile function recovery
October 20, 2014
The application of dehydrated human amniotic membrane as a therapeutic patch covering the neurovascular bundle may have profound effects on the early recovery of erectile function in men undergoing nerve-sparing, robot-assisted laparoscopic radical prostatectomy, a retrospective study suggests.
Taipei, Taiwan-The application of dehydrated human amniotic membrane (dHAM) as a therapeutic patch covering the neurovascular bundle may have profound effects on the early recovery of erectile function in men undergoing nerve-sparing, robot-assisted laparoscopic radical prostatectomy, a retrospective study suggests.
The study examined 60 patients who underwent surgery for low-volume prostate cancer. Of 22 men receiving an AmnioFix (MiMedx, Marietta, GA) dHAM during a bilateral nerve-sparing procedure, 20 (90.9%) demonstrated a return of erectile function at 3 months, and 21 men (95.5%) recovered function at 6 months. In 38 men undergoing the same procedure but without the dHAM, 16 (42.1%) recovered erectile function at 3 months and 20 (52.6%) at 6 months (p=.0005 at 3 months and ≤.0002 at 6 months for the cohort comparisons).
The patch appears to assert its influence early. Only two of the men (5.26%) without the patch had erectile function at first follow-up compared to nine of men (40.9%) receiving the patch (p=.0006).
"I think we now have a means of circumventing some of the surgical trauma (associated with nerve-sparing prostatectomy). No matter how good we are, we inflict some trauma on these fine, delicate nerves," Sanjay Razdan, MD, MCh, director of the International Robotic Prostatectomy Institute and associate professor of urology at the Herbert Wertheim College of Medicine, Florida International University, Miami, told Urology Times.
Dr. Razdan, the study's lead author and sole surgeon, said the insults to the neurovascular bundle included thermal injury, inflammation, traction injury, and scar tissue formation.
"I think that adding this layer of protection with a dehydrated amniotic membrane is going to go a long way in bringing a rapid return of erectile function," he said.
Dr. Razdan explained that the dHAM derived its effects from a rich trove of growth factors such as TGF-a and TGF-b, which encourage wound healing; bFGF, which promotes cell growth and tissue repair; and factors such as EGF, PDGF, and VEGF, all of which mediate the proliferation and differentiation of cells. These factors have anti-inflammatory properties as well as anti-scarring effects.
Dr. Razdan said the procedure is not particularly challenging but that there is a definite learning curve.
"Once the prostatectomy is completed but before the urethral anastomosis is conducted, the membrane is passed to the site via a 12-mm side port,” he explained. “My assistant rolls up the membrane, which is like parchment. It has to remain perfectly dry as it passes through the port because if it gets wet, you can't handle it. I grab it with the robotic arm and depending on the thickness and width of the neurovascular bundle, it can be placed as one sheet or if the bundles are wide apart, it can be cut into two sheets.
“It is wrapped around the nerve. The moment it gets moist, it sticks. There is no need for sutures. The sides are labeled 'up' and 'down.' The 'down' side goes onto the nerve. Otherwise, it will not stick.”
The study was recognized as "The Best Paper in Robotics" following its presentation at the World Congress of Endourology and SWL in Taipei, Taiwan. The retrospective trial consisted of 22 dHAM patients and 38 controls with low-volume prostate cancer and good pre-procedure erections. Dr. Razdan conducted all procedures. The average age in the control group was 62 years (48-70) compared to 59 years (40-73) in the membrane group. Gleason scores for the controls were ≤6, 55%; 7, 45%; and 8-10, none. The Gleason scores for the membrane group were ≤ 6, 50%; 7, 36%; and 8-10, 14%. The mean International Index of Erectile Function score for the control group was 19.84 (SD, 3.02) compared to 20 (SD, 3.5) for the membrane group.
Given the responses seen in a pilot study, the WCE study, and initial data from a recently closed prospective randomized study, Dr. Razdan now offers the membrane to all patients who meet criteria of having low-volume disease and good preoperative erections. As might be expected, the costs of the procedure have yet to be covered by insurance.
One of the surprising aspects of the study may be that the membrane has not been used in prostatectomies earlier, said Dr. Razdan. He added that this is the first documented study in the world using dHAM during robotic prostatectomy. Dr. Razdan said he first learned of the membrane in a casual cafeteria conversation with a neurosurgeon. A subsequent literature search showed the membrane to have a well-established role in general, orthopedic, neurologic, podiatric, bariatric, and plastic surgeries.
Dr. Razdan received free membranes from MiMedx for the retrospective trial.