This policy originated from an Arkansas Blue Cross Blue Shield Technology Assessment in May 2001.

 

Limited data are published regarding the long-term outcomes of sural nerve grafting; the largest study reported is a case series of 23 men with a mean 23-month follow-up.  All men had clinically localized, but high-volume prostate cancer such that bilateral resection of the neurovascular bundles was considered necessary. Before surgery, all men reported spontaneous erection. Outcomes included assessment of erectile function based on:

Patients were also encouraged to use a variety of erectile dysfunction treatments, including intracavernosal injections, vacuum constriction devices, or sildenafil citrate, as needed. The results were compared to a group of 12 men who were potent preoperatively and had undergone prostatectomy with bilateral nerve resection, but who declined nerve graft placement. Of the 23 men undergoing nerve graft, 6 (26%) had spontaneous, medically unassisted erection sufficient for sexual intercourse. An additional 6 men (26%) reported 40% to 60% spontaneous erection that was insufficient for intercourse; 4 of these patients were able to have intercourse using sildenafil. Therefore, a total of 10 of the 23 patients were able to have intercourse, either spontaneously or with pharmacologic therapy. A total of 11 men had no clinical response even with the use of sildenafil. Not unexpectedly, all outcomes were significantly better compared to the control group. Side effects of the sural nerve donor site, which included incisional pain and a sensory deficit along the lateral aspect of the foot, were considered tolerable. The authors noted improvement 8 to 12 months postoperatively and accelerated improvement at 12 to 18 months postoperatively. In addition there are reports from the same group of surgeons who reported in 2001 that some 220 sural nerve grafts had been performed at their institution.  Some surgeons have performed unilateral sural nerve grafts. However, without a controlled study in this population, it will be difficult to isolate the contribution of the sural nerve graft compared to the spontaneous recovery of erectile activity.

 

In summary, the data are insufficient to permit scientific conclusions regarding the long-term effectiveness of sural nerve grafting in men undergoing prostatectomy.

 

A search of the literature did not identify any additional published articles that would alter the above conclusions; therefore, the policy statement is unchanged. Singh and colleagues investigated whether unilateral sural nerve graft would improve urinary function after radical prostatectomy.  Patients with and without a sural nerve graft were invited to complete a questionnaire. At 12 months after surgery, 94.7% of patients with a sural nerve graft reported complete urinary control compared to 58.3% without a sural nerve graft. The authors concluded that these preliminary results required validation in larger, multicenter, prospective randomized studies. No additional studies were identified that focused on the outcome of potency.

 

A search of the literature was conducted through February 2007. Secin and colleagues reported results on 44 consecutive patients who underwent bilateral nerve grafting from 1999 to 2004 at Memorial Sloan-Kettering Cancer Center.   The overall five-year recovery of erectile function was 34% and the rate of consistent function was 11%. None of a number of variables (e.g. age, type of nerve (sural, genitofemoral, ilioinguinal), comorbidities, etc.) were significantly associated with recovery of postoperative erectile function. The authors concluded that nerve grafts might be beneficial in select patients; but that a randomized controlled trial was needed.

 

Sim reported on two-year results in 41 patients who received unilateral sural nerve grafts following radical prostatectomy when one neurovascular bundle was resected.  In this series, recovery of erectile function was reported for 63% of patients (based on 24 of 38 patients). This paper also reported on erectile function on another group of patients who had unilateral resection at the same institution but without a nerve graft. In this group that was older and was not a matched on key characteristics to the group who received a nerve graft, the erectile function was 26.5% (13 of 49). Nelson reported on results of using genitofemoral nerve grafts in 27 patients (5 with bilateral grafts) with radical prostatectomy.  At a mean follow up of 14 months, 56% of patients reported erectile function sufficient for penetration. The authors noted uncertainly about whether their findings were a consequence of an effective unilateral nerve-sparing dissection or of the nerve grafting.

 

While these numerous studies demonstrate that unilateral or bilateral nerve grafting is feasible, whether or not this technique results in improved patient outcomes following radical prostatectomy requires further study in randomized controlled trials. Thus, the policy statement is unchanged.

 

A literature search was conducted using MEDLINE for February 2007 to April 2008. The studies identified were small, single-center cohort studies; some had non-grafted comparison groups. Several studies report on small numbers (3 to 6 patients) with bilateral grafting that are insufficient for making comparisons or conclusions.

 

Zorn et al (2008) reported the experience of 27 nerve grafted (23 unilateral, 4 bilateral) sural nerve grafts on sexual and urological function over a mean of 26 months.  Several comparisons were made using their prospectively collected database of non-grafted patients. At one year, continence rates were not different for the grafted and non-grafted but nerve(s) spared groups. Sexual function was defined using validated questionnaires, and 24 of 27 nerve grafted patients were potent preoperatively. No differences between unilateral nerve graft and unilateral nerve sparing with no grafting were noted with respect to return to baseline sexual function. At mean follow-up of 26 months, 47.8% of unilaterally grafted patients had regained potency, compared to 56% for age matched unilateral nerve sparing with no grafting.

 

Namiki et al (2007) published a 3-year study from Japan of the results of unilateral sural nerve graft on recovery of sexual and urological function. A total of 113 patients were compared: 19 patients with unilateral nerve sparing plus sural nerve graft, 60 patients with unilateral nerve sparing but no grafting, and 34 patients with bilateral nerve sparing surgery. Sexual function was assessed with validated questionnaires and at 2 years there was no difference between the nerve grafted and the bilateral nerve sparing patients with regard to sexual function scores. At 3 years, 25 and 28% of patients in the nerve grafted and bilateral nerve sparing patients respectively considered their sexual function as fair or good. Urinary function returned to baseline in the nerve grafted and bilateral nerve sparing groups at 6 months and in the unilateral nerve spring group at 12 months. Differences in sexual function were present at baseline with the nerve grafted and bilateral nerve sparing patients reporting higher baseline function than the unilateral nerve sparing group.

 

Randomized trails are still warranted in order to discern the effects of nerve grafting and nerve sparing and to remove selection biases present in the current studies.  The impact of nerve grafting in association with radical prostatectomy on outcomes is unknown.  The statement of noncoverage remains.

 

 

 

 

 

 

 

 

In 2014, Siddiqui et al reported 3-year follow-up on 66 men with clinically localized prostate cancer who had undergone sural nerve grafting during radical retropublic prostatectomy (Siddiqui, 2014). Forty-three (65%) were unilateral nerve grafts, and 23 (36%) were bilateral. All procedures were performed by a single surgeon. Recovery of potency was defined as a postoperative International Inventory of Erectile Function (IIEF) score greater than 22. Patients were permitted to use phosphodiesterase type 5 inhibitors) for erectile dysfunction. The mean preoperative IIEF score was 23.4 (SD 1.6), and postoperatively, 19 patients (28.8%) recovered potency ie, had an IIEF score greater than 22. When stratified by graft type, erectile function recovery rates were 28% after unilateral and 30% after bilateral nerve grafting.