Study shows genitofemoral grafts feasible during RP

June 1, 2005

San Antonio--Genitofemoral (GF) nerve grafting during radical retropubic prostatectomy can be performed safely with a low risk of postoperative morbidity and shows promising efficacy for returning erectile function after surgery involving wide nerve resection, according to the results of a retrospective study.

San Antonio-Genitofemoral (GF) nerve grafting during radical retropubic prostatectomy can be performed safely with a low risk of postoperative morbidity and shows promising efficacy for returning erectile function after surgery involving wide nerve resection, according to the results of a retrospective study.

The investigation, undertaken by urologists from Vanderbilt University, Nashville, TN, considered men who had undergone RP between 2001 and 2003. Of 457 men operated on during the study period, 27 underwent genitofemoral nerve grafting. Twenty-two men (81%) received a single nerve graft with nerve-sparing contralaterally, and the remaining five men (19%) had a bilateral graft that was accomplished by harvesting a single nerve in three of the five men. All of the surgeries were performed by Joseph A. Smith, Jr, MD, professor and chairman of Vanderbilt's department of urology.

Minimal morbidity was noted during a mean follow-up of 14 months. Results from a non-validated questionnaire asking men to indicate presence and severity of numbness or pain in the ipsilateral thigh or in the ipsilateral scrotum showed only two patients (6.5%) had postoperative side effects. Both reported a decrease in sensation in the ipsilateral anterior thigh and rated severity as almost none or not bothersome.

"The GF nerve, which is readily available during RP, was the first tissue used in animal studies of nerve grafting to restore erectile function after RP. While there have been concerns about significant patient morbidity when this procedure was performed clinically, the results of this study support the feasibility and safety of GF nerve grafting in men undergoing RP."

Adequate preoperative data on erectile function were not consistently available in this retrospective study, but an exploratory analysis was performed to determine potency outcomes. The results showed 56% of the 27 men could achieve an erection firm enough for penetration either spontaneously or with sildenafil citrate (Viagra).

Consistent with data from studies of men having standard nerve-sparing prostatectomy, subgroup analyses showed a better outcome among men with normal erectile function preoperatively compared with those having any degree of dysfunction. Within those two groups, proportions of men achieving erections sufficient for penetration were 69% (9/13 men) and 43% (6/14 men), respectively.

When men were stratified by whether they had a unilateral or bilateral graft, rates of return of an erection firm enough for penetration were 52% and 20%, respectively, Dr. Nelson reported.

"Although the follow-up is still early and no definitive conclusions can be drawn regarding erectile function given our study design, the rates of return noted, especially among men who had a bilateral graft, are very encouraging," he said.

Dr. Nelson noted historical data indicates that when a bilateral wide neurovascular bundle resection is properly done for sound oncologic principles, less than 5% to 10% of men will have erectile function postoperatively.

"Our results suggest there may be a benefit for the nerve grafting and also compare favorably with previous studies using the sural nerve that report approximately one-third of men recover erectile function after a bilateral graft procedure," he said.

Prospective study underway To better define the effects of the procedure on erectile function, a prospective study is now underway enrolling men who need to undergo radical prostatectomy with wide unilateral or wide bilateral nerve resection. Erectile function will be assessed pre- and postoperatively using the validated International Index of Erectile Function (IIEF) and other potency tools.

Patients will be stratified by various factors, and potency outcomes for those subgroups will be compared with appropriately matched cohorts who underwent prostatectomy without nerve grafts during the same time period.

Of particular interest, the research at Vanderbilt will also include patients undergoing robotically assisted laparoscopic prostatectomy.

"We have performed a number of procedures with genitofemoral nerve grafting using the robot and intend to include this group in our prospective studies," Dr. Nelson said.