Two-year outcome of unilateral sural nerve interposition graft after radical prostatectomy

Erectile Dysfunction: Treatments, Advances and New Therapeutic Strategies

Erectile dysfunction (ED) is the inability to get and maintain an adequate penile erection for satisfactory sexual intercourse. Due to its negative impacts on men's life quality and increase during aging (40% of men between 40 and 70 years), ED has always attracted researchers of different disciplines, from urology, andrology and neuropharmacology to regenerative medicine, and vascular and prosthesis implant surgery. Locally and/or centrally acting drugs are used to treat ED, e.g., phosphodiesterase 5 inhibitors (first in the list) given orally, and phentolamine, prostaglandin E1 and papaverine injected intracavernously. Preclinical data also show that dopamine D4 receptor agonists, oxytocin and α-MSH analogues may have a role in ED treatment. However, since pro-erectile drugs are given on demand and are not always efficacious, new strategies are being tested for long lasting cures of ED. These include regenerative therapies, e.g., stem cells, plasma-enriched platelets and extracorporeal shock wave treatments to cure damaged erectile tissues. Although fascinating, these therapies are laborious, expensive and not easily reproducible. This leaves old vacuum erection devices and penile prostheses as the only way to get an artificial erection and sexual intercourse with intractable ED, with penile prosthesis used only by accurately selected patients.

The Potential Role of C-peptide in Sexual and Reproductive Functions in Type 1 Diabetes Mellitus: An Update

BACKGROUND

Although hyperglycaemia is known to be the leading cause of diabetic complications, the beneficial effect of optimal glucose control in preventing diabetic complications is still far from being proven. In fact, such complications may not be related to glycaemic control alone.

OBJECTIVE

This review summarizes several studies that suggest that a C-peptide deficiency could be new and common pathophysiology for complications in type 1 diabetes, including sexual and reproductive dysfunction.

METHODS

We reviewed in vitro, in vivo, and human studies on the association between C-peptide deficiency or C-peptide replacement therapy and complications in type 1 diabetes. It seems that Cpeptide replacement therapy may interrupt the connection between diabetes and sexual/reproductive dysfunction.

RESULTS

The Diabetes Control and Complications Trial suggested that maintaining C-peptide secretion is associated with a reduced incidence of retinopathy, nephropathy, and hypoglycaemia. Risk of vascular, hormonal, and neurologic damage in the structures supplying blood to the penis increases with increasing levels of HbA1. However, several human studies have suggested an association between C-peptide production and hypothalamic/pituitary functions. When exposed to C-peptide, cavernosal smooth muscle cells increase the production of nitric oxide. C-peptide in diabetic rats improves sperm count, sperm motility, testosterone levels, and nerve conduction compared to non-treated diabetic rats.

CONCLUSION

C-peptide deficiency may be involved, at least partially, in the development of several pathological features associated with type 1 diabetes, including sexual/reproductive dysfunction. Preliminary studies have reported that C-peptide administration protects against diabetic microand macrovascular damages as well as sexual/reproductive dysfunction. Therefore, further studies are needed to confirm these promising findings.

Anatomy of the sural nerve complex: Unaccounted anatomic variations and morphometric data

BACKGROUND

The sural nerve (SN) is a cutaneous sensory nerve innervating the posterolateral leg. The SN is formed from a highly variable set of contributing nerves called the sural nerve complex (SNC). The SNC is made up of the lateral sural cutaneous nerve, medial sural cutaneous nerve, sural communicating branch, and SN. The SN is frequently cited as the most common donor nerve graft and is commonly injured in procedures of the lower extremity. Recent meta-analysis standardized six morphologies of the SNC and established a required reporting criterion for the group of nerves forming the SN. Due to the inconsistencies in previous literature, this study will group observed SNC's by one of these six SNC morphologies to assess and validate the meta-analysis grouping criteria. This study will also collect the same morphometric data previously outlined in order to grow the number of samples that are reported in a standardized fashion.

METHODS

100 formalin and 4 Theil preserved cadavers (n = 208) lower limbs were bilaterally dissected at Kansas City University and Creighton University School of Dentistry to observe the SNC in its entirety on the posterolateral leg. Anatomic data was captured utilizing the standardized morphologies types 1-6 with two sub-typing. Nerves that were found to be outside of this categorization were placed in an unassigned grouping.

RESULTS

The most prevalent SNCs were type 1 at 41.35% (n = 86) and type 3 nerves at 34.62% (n = 72). Type 2 was found 8.65% (n = 18), type 4 and 5 were found each at 0.48% (n = 1). Type 6 was not observed. When comparing the present studies frequency of nerve types 1-6 to the meta-analysis a sub-grouping of "North American" cadaveric studies a X² = .903 p = .030 was found. Two distinct and previously unassigned formations of the SNC were 10.58% (n = 20) and 3.85% (n = 8) of data. These two SNC are termed type 7 & 8, these represent two formations of SN that are outside of what was previously reported. 15.87% (n = 33) did not match visual descriptions based on nerve origin of a type 1 SNC but met written definitions. These were termed type 1A1 and type 1A2. The SNC was asymmetrical in 57.69% (n = 120). The pooled mean length of the SN was 32.97 ± 14.12 cm (31.05-34.88), mean diameter was 2.31 ± 0.83 mm (2.20-2.42, and the distance of the posterior border of the lateral malleolus to the SN was found to be 1.72 ± 0.70 cm (1.63-1.80).

CONCLUSION

Anatomic variation in the SNC is highly variable, yet is consistent with previously observed literature. This study demonstrates two unaccounted formations of the SNC as well as two additional subcategories of SNC that were not included in the previous meta-analysis. These four variants warrant inclusion as standard formations of the SNC due to the high prevalence observed in this study as well as historical consistency observed in previous literature and case reports. These two SNC formations increase the risk of iatrogenic injury during surgical interventions of the lower extremity. Morphometric data describing the spatial relationship of this nerve complex on the posterolateral leg is consistent with previously reported data and aids in generating a large data set for future studies to characterize spatial properties of this nerve complex.

Cavernous Branched Nerve Regeneration Using Non-Tubular Artificial Nerve Sheets Using Freeze-Dried Alginate Gel Combined With Polyglycolic Acid Mesh in a Rat Model

Introduction

Neuroprotection and neuroregeneration of cavernous nerve plexus by biological/bioengineering solutions may have the potential to maintain erectile function.

Aims

We evaluated the efficacy of a newly developed artificial nerve sheet using freeze-dried alginate (ALG) with polyglycolic acid (PGA) mesh in a rat model. Methods: Bilateral cavernous nerves of male rats were excised to make an approximately 2 mm gap. A piece of the sponge-like freeze-dried sheet created by covalent cross-linking of ALG gel combined with PGA mesh was placed over the gap to cover each stump without any neural anastomosis. We compared erectile functions in the ALG groups with those in the sham group and the bilateral nerve excision group (n = 12, each).

Main Outcome Measures

Main outcome measure was a rat model with cavernous nerve excision.

Results

All rats in the sham group had erection at 63 or 64 days, and mating behavior was confirmed in 10 rats (83.3%) of the sham group at 56 to 62 days. No erection and mating behavior was observed in the excision group. Ten of the 12 (83.3%) rats in the ALG group had a mating behavior and an erection, and the rates of erection and mating behavior were significantly higher in the ALG group than those in the excision group (P < .01, P < .01, respectively). Using a retrograde FluoroGold, the rate of FluoroGold positive pelvic ganglia proximal to the gap at 61 or 62 days was significantly higher in the ALG group than that in the excision group (P = .014).

Conclusion

The results of our animal study have demonstrated that simply filling the cavernous nerve gap using the non-tubular artificial nerve sheets made of ALG with PGA mesh restored erectile function after cavernous nerve excision.

Narita S, Obara T, Ishikawa N, et al. Cavernous Branched Nerve Regeneration Using Non-Tubular Artificial Nerve Sheets Using Freeze-Dried Alginate Gel Combined With Polyglycolic Acid Mesh in a Rat Model. Sex Med 2021;9:100308.

Emerging nonsurgical and surgical techniques to treat erectile dysfunction: A systematic review of treatment options and published outcomes

Erectile dysfunction (ED) is one of the most common causes of morbidity in male patients, with a prevalence of 50-60% in men aged 40-70 years. EDs may be caused by physical or psychological trauma, the former of which may be treatable through surgical intervention. Physical trauma may be further categorized as vasculogenic, neurogenic, or idiopathic in nature. Although many patients do not respond well to nonsurgical treatment options, few opt for surgical intervention. This is likely due to the difficulty of the procedures, as well as relatively low historical success rates. As such, a systematic review of the literature was performed to identify novel surgical interventions for ED. A total of 19 manuscripts were included in this review, representing data of three minimally invasive approaches to ED treatment and seven novel surgical techniques. The data revealed compelling evidence in support of microsurgical treatments for ED - namely, microvascular arterial bypass penile revascularization surgery (MABS) and cavernous nerve graft reconstruction. Nerve grafts varied, with the use of end-to-side ilioinguinal, genitofemoral, and sural grafts, all demonstrating high rates of success. Furthermore, minimally invasive botulinum toxin (BoNT-A) treatment and adipose-derived stem cell (ADSC) therapy have shown extreme promise in rat models; with BoNT-A treatment entering phase II human clinical trials this year. Many of the surgical methods investigated in this review are microsurgical interventions that demonstrate high rates of success in patients with neurogenic or vasculogenic ED. As such, microsurgeons are uniquely trained and positioned to be of value to ED treatment.

Surgical Factors Associated With Male and Female Sexual Dysfunction After Radical Cystectomy: What Do We Know and How Can We Improve Outcomes?

BACKGROUND

Sexual dysfunction after radical cystectomy (RC) is a frequent, though commonly overlooked symptom for both men and women. Improved oncological outcomes and the rising number of bladder cancer survivors mandate physicians to closely address and evaluate post-surgical sexual dysfunction and offer goal-directed treatment. Improvements in RC surgical techniques that promote post-operative sexual function have been proposed, alongside new quality-of-life inventories and sexual function therapeutic options; however, rigorous studies in the field are lacking.

AIM

To provide a comprehensive overview of post-RC sexual dysfunction and discuss new surgical techniques, sexual dysfunction evaluation, and novel treatment strategies.

METHODS

A non-systematic narrative review of the literature was performed through PubMed about sexual dysfunction in men and women after RC.

OUTCOMES

We reported on the surgical anatomy of sexual function-sparing RC, the most common inventories used to investigate sexual function in post-RC patients, and current treatment options.

RESULTS

Extensive knowledge about pelvic anatomy and nerve-sparing surgical techniques in men is well understood from studies about prostate anatomy and nerve-sparing prostatectomy. However, anatomical and surgical details of sexual-sparing RC in women needs further characterization. Several questionnaires are used to investigate sexuality after RC, but a standardized approach is still missing. Therapeutic options are available to treat sexual dysfunction, but limited studies have been conducted to specifically address the post-RC population.

CONCLUSION

Further work is needed to understand the best strategies to prevent and treat sexual dysfunction in patients after RC. Pederzoli F, Campbell JD, Matsui H, et al. Surgical Factors Associated With Male and Female Sexual Dysfunction After Radical Cystectomy: What Do We Know and How Can We Improve Outcomes? Sex Med Rev 2018;6:469-481.

Interpositional Nerve Grafting of the Prostatic Plexus after Radical Prostatectomy

Background:

Injury to the prostatic plexus may occur during radical prostatectomy even with the use of minimally invasive techniques. Reconstruction of these nerves by interpositional nerve grafting can be performed to reduce morbidity. Although the feasibility of nerve reconstruction has been shown, long-term functional outcomes are mixed, and the role of nerve grafting in these patients remains unclear.

Methods:

A retrospective study was performed on 38 consecutive patients who underwent immediate unilateral or bilateral nerve reconstruction after open prostatectomy. Additionally, 53 control patients who underwent unilateral, bilateral, or non–nerve-sparing open prostatectomy without nerve grafting were reviewed. Outcomes included rates of urinary continence, erections sufficient for sexual intercourse, and ability to have spontaneous erections. Analysis was performed by stratifying patients by D’Amico score and laterality of nerve involvement.

Results:

Unilateral nerve grafting conferred no significant benefit compared with unilateral nerve-sparing prostatectomy. Bilateral nerve-sparing patients demonstrated superior functional outcomes compared with bilateral non–nerve-sparing patients, whereas bilateral nerve-grafting patients displayed a trend toward functional improvement. With increasing D’Amico score, there was a trend toward worsening urinary continence and erectile function regardless of nerve-grafting status.

Conclusions:

In the era of robotic prostatectomy, interpositional nerve reconstruction is not a routine practice. However, the substantial morbidity experienced in patients with bilateral nerve resections remains unacceptable, and therefore, nerve grafting may still improve functional outcomes in these patients. Further investigation is needed to improve the potential of bilateral nerve grafting after non–nerve-sparing prostatectomy.

Surgical management of prostate cancer

Surgery remains a mainstay in the management of localized prostate cancer. This article addresses surgical aspects germane to the management of men with prostate cancer, including patient selection for surgery, nerve-sparing approaches, minimization of positive surgical margins, and indications for pelvic lymph node dissection. Outcomes for men with high-risk prostate cancer following surgery are reviewed, and the present role of neoadjuvant therapy before radical prostatectomy is discussed. In addition, there is a review of the published literature on surgical ablative therapies for prostate cancer.

Reconstruction of the abdominal vagus nerve using sural nerve grafts in canine models

Background

Recently, vagus nerve preservation or reconstruction of vagus has received increasing attention. The present study aimed to investigate the feasibility of reconstructing the severed vagal trunk using an autologous sural nerve graft.

Methods

Ten adult Beagle dogs were randomly assigned to two groups of five, the nerve grafting group (TG) and the vagal resection group (VG). The gastric secretion and emptying functions in both groups were assessed using Hollander insulin and acetaminophen tests before surgery and three months after surgery. All dogs underwent laparotomy under general anesthesia. In TG group, latency and conduction velocity of the action potential in a vagal trunk were measured, and then nerves of 4 cm long were cut from the abdominal anterior and posterior vagal trunks. Two segments of autologous sural nerve were collected for performing end-to-end anastomoses with the cut ends of vagal trunk (8–0 nylon suture, 3 sutures for each anastomosis). Dogs in VG group only underwent partial resections of the anterior and posterior vagal trunks. Laparotomy was performed in dogs of TG group, and latency and conduction velocity of the action potential in their vagal trunks were measured. The grafted nerve segment was removed, and stained with anti-neurofilament protein and toluidine blue.

Results

Latency of the action potential in the vagal trunk was longer after surgery than before surgery in TG group, while the conduction velocity was lower after surgery. The gastric secretion and emptying functions were weaker after surgery in dogs of both groups, but in TG group they were significantly better than in VG group. Anti-neurofilament protein staining and toluidine blue staining showed there were nerve fibers crossing the anastomosis of the vagus and sural nerves in dogs of TG group.

Conclusion

Reconstruction of the vagus nerve using the sural nerve is technically feasible.

Tissue engineering and stem cells: basic principles and applications in urology

To overcome problems of damaged urinary tract tissues and complications of current procedures, tissue engineering (TE) techniques and stem cell (SC) research have achieved great progress. Although diversity of techniques is used, urologists should know the basics. We carried out a literature review regarding the basic principles and applications of TE and SC technologies in the genitourinary tract. We carried out MEDLINE/PubMed searches for English articles until March 2010 using a combination of the following keywords: bladder, erectile dysfunction, kidney, prostate, Peyronie's disease, stem cells, stress urinary incontinence, testis, tissue engineering, ureter, urethra and urinary tract. Retrieved abstracts were checked, and full versions of relevant articles were obtained. Scientists have achieved great advances in basic science research. This is obvious by the tremendous increase in the number of publications. We divided this review in two topics; the first discusses basic science principles of TE and SC, whereas the second part delineates current clinical applications and advances in urological literature. TE and SC applications represent an alternative resource for treating complicated urological diseases. Despite the paucity of clinical trials, the promising results of animal models and continuous work represents the hope of treating various urological disorders with this technology.

Interposition nerve grafting during radical prostatectomy: cumulative review and critical appraisal of literature

In 1997, the first report of sural nerve interposition grafting during radical prostatectomy was published in Urology. The favorable findings in this initial pilot study generated numerous follow-up reports that have demonstrated conflicting and contradictory outcomes. Certainly, controversy exists regarding the true benefit of nerve grafting. This review will objectively and critically summarize the salient literature, discuss evolving techniques, and offer insight into the future of interposition grafting in the current era of clinically localized prostate cancer and robotic prostatectomy.

Randomized phase II trial evaluation of erectile function after attempted unilateral cavernous nerve-sparing retropubic radical prostatectomy with versus without unilateral sural nerve grafting for clinically localized prostate cancer

BACKGROUND

Nonrandomized studies of unilateral nerve-sparing (UNS) radical prostatectomy (RP) have reported improved recovery of erectile function if the sacrificed cavernous nerve is reconstructed with a sural nerve graft (SNG).

OBJECTIVE

To determine whether UNS RP plus SNG results in a 50% relative increase in potency at 2 yr compared to UNS RP alone.

DESIGN, SETTING, AND PARTICIPANTS

The study enrolled patients from October 2001-May 2006 from a single academic center and was randomized, open label. Participants were men with localized prostate cancer recommended for UNS RP, less than 66 yr old, normal baseline erectile function, and willing to participate in early erectile dysfunction (ED) therapy. Patients were followed up to 2 yr.

INTERVENTION

Patients underwent UNS RP and ED therapy starting at 6 wk: oral prostaglandin type-5 (PDE5) inhibitor, vacuum erection device (VED), and intracavernosal injection therapy. In the SNG group, a plastic surgeon performed the procedure at the time of RP.

MEASUREMENTS

The ability to have an erection suitable for intercourse with or without a PDE5 inhibitor at 2 yr. The hypothesis was that SNG would result in a 60% potency rate compared to 40% for controls (80% power, 5% two-way significance).

RESULTS AND LIMITATIONS

The trial planned to enroll 200 patients, but an interim analysis at 107 patients met criteria for futility and the trial was closed. For patients completing the protocol to 2 yr, potency was recovered in 32 of 45 (71%) of SNG and 14 of 21 (67%) of controls (p=0.777). By intent-to-treat analysis, potency recovered in 32 of 66 (48.5%) of SNG and 14 of 41 (34%) of controls (p=0.271). No differences were seen in time to potency or quality of life scores for ED and urinary function. Limitations included slower-than-expected accrual and poor compliance with ED therapy: <65% for VED and <40% for injections.

CONCLUSIONS

The addition of SNG to a UNS RP did not improve potency at 2 yr following surgery.

TRIAL REGISTRATION

ClinicalTrials.gov, Identifier: NCT00080808, http://www.clinicaltrials.gov/ct2/show/NCT00080808?term=NCT00080808&rank=1.

Recovery of erectile function after unilateral and bilateral cavernous nerve interposition grafting during radical pelvic surgery

PURPOSE

The use of cavernous nerve interposition grafting to preserve erectile function in men who require neurovascular bundle resection for cancer control is controversial. We report outcomes and predictors of cavernous nerve interposition grafting in men undergoing unilateral grafting during radical prostatectomy or bilateral grafting during radical cystectomy and prostatectomy with autologous nerve grafts.

MATERIALS AND METHODS

We retrospectively reviewed the electronic records of 36 patients who underwent cavernous nerve interposition grafting between 2003 and 2006. Postoperatively erectile function was assessed with the International Index of Erectile Function 15-item questionnaire. Predictors of potency, including age at surgery, time since surgery and prostate specific antigen at surgery, were assessed by univariate analysis.

RESULTS

A total of 33 patients (92% response rate) were followed for a median of 32, 25 and 11 months after bilateral grafting during radical cystectomy (10), unilateral grafting during radical prostatectomy (20), and bilateral grafting during radical cystectomy and prostatectomy (3), respectively. The rate of potency, defined as the ability to attain and maintain erection sufficient for penetration at least 50% of the time with or without phosphodiesterase-5 inhibitors, was 31% (5 of 13 men) for unilateral grafts, 38% (5 of 16) for bilateral grafts and 30% (3 of 10) for bilateral grafts during radical cystectomy. Age at surgery was the only significant determinant of potency and it showed an inverse relationship in the bilateral nerve graft group (p = 0.02).

CONCLUSIONS

Cavernous nerve interposition grafting appears to have a role in the recovery of erectile function. To our knowledge this study represents the largest series of cavernous nerve interposition grafting during cystectomy and it suggests that this should be considered during bilateral neurovascular bundle resection.

Factors affecting erectile function after radical retropubic prostatectomy: results from 1620 consecutive patients

OBJECTIVE

To report the return of erectile function in 1620 consecutive men after radical retropubic prostatectomy (RRP), chosen by half of men diagnosed with clinically localized prostate cancer, and the goal of which is to completely excise the tumour while preserving continence and erectile function.

PATIENTS AND METHODS

From January 1992 to October 2006, one surgeon performed RRP with a nerve-sparing technique where feasible. Men with erectile dysfunction before surgery, salvage RRPs, those not having a nerve-sparing procedure, neoadjuvant or adjuvant therapy within 6 months of RRP and a follow-up of <6 months were excluded from the analyses. Erectile function was evaluated by the surgeon when possible or by an annual questionnaire. Potency was defined as erectile function sufficient for intercourse with or without a phosphodiesterase-5 inhibitor.

RESULTS

Of 619 men who had a bilateral and of 178 who had a unilateral nerve-sparing RRP, 72% and 53%, respectively, were potent. When stratifying by age groups (<or=49, 50-59, 60-69 and >or=70 years) potency rates were 86%, 76%, 58% and 37%, respectively. Potency was more common after bilateral than unilateral nerve-sparing RRP in all age groups (P < 0.001). Age, bilateral nerve-sparing (odds ratio 2.9) and surgeon experience were associated with potency in a multivariate analysis.

CONCLUSION

Careful patient selection and meticulous surgical technique are essential to achieve the right balance between cancer control and morbidity. The patient's age, nerve-sparing RRP and the surgeon's experience were the significant predictors of return of potency after RRP.