Impact of unilateral interposition sural nerve grafting on recovery of urinary function after radical prostatectomy

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.

Patient- and Tumour-related Prognostic Factors for Urinary Incontinence After Radical Prostatectomy for Nonmetastatic Prostate Cancer: A Systematic Review and Meta-analysis

CONTEXT

While urinary incontinence (UI) commonly occurs after radical prostatectomy (RP), it is unclear what factors increase the risk of UI development.

OBJECTIVE

To perform a systematic review of patient- and tumour-related prognostic factors for post-RP UI. The primary outcome was UI within 3 mo after RP. Secondary outcomes included UI at 3-12 mo and ≥12 mo after RP.

EVIDENCE ACQUISITION

Databases including Medline, EMBASE, and CENTRAL were searched between January 1990 and May 2020. All studies reporting patient- and tumour-related prognostic factors in univariable or multivariable analyses were included. Surgical factors were excluded. Risk of bias (RoB) and confounding assessments were performed using the Quality In Prognosis Studies (QUIPS) tool. Random-effects meta-analyses were performed for all prognostic factor, where possible.

EVIDENCE SYNTHESIS

A total of 119 studies (5 randomised controlled trials, 24 prospective, 88 retrospective, and 2 case-control studies) with 131 379 patients were included. RoB was high for study participation and confounding; moderate to high for statistical analysis, study attrition, and prognostic factor measurement; and low for outcome measurements. Significant prognostic factors for postoperative UI within 3 mo after RP were age (odds ratio [OR] per yearly increase 1.04, 95% confidence interval [CI] 1.03-1.05), membranous urethral length (MUL; OR per 1-mm increase 0.81, 95% CI 0.74-0.88), prostate volume (PV; OR per 1-ml increase 1.005, 95% CI 1.000-1.011), and Charlson comorbidity index (CCI; OR 1.28, 95% CI 1.09-1.50).

CONCLUSIONS

Increasing age, shorter MUL, greater PV, and higher CCI are independent prognostic factors for UI within 3 mo after RP, with all except CCI remaining prognostic at 3-12 mo.

PATIENT SUMMARY

We reviewed the literature to identify patient and disease factors associated with urinary incontinence after surgery for prostate cancer. We found increasing age, larger prostate volume, shorter length of a section of the urethra (membranous urethra), and lower fitness were associated with worse urinary incontinence for the first 3 mo after surgery, with all except lower fitness remaining predictive at 3-12 mo.

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.

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.

Histologic and electrophysiological study of nerve regeneration using a polyglycolic acid-collagen nerve conduit filled with collagen sponge in canine model

OBJECTIVES

To determine the rate of achieving electrophysiologically proved functional recovery by autonomic nerve regeneration, with the aid of an artificial nerve conduit.

METHODS

A polyglycolic acid (PGA) collagen nerve conduit filled with collagen sponge was interposed in a 10-mm-long gap of the right hypogastric nerve (HGN) in 16 dogs. Histologic evaluation of nerve regeneration and electrophysiological analysis at 2 weeks and 2, 3, 4, 5, 6, 7, and 8 months (n = 2, each) after surgery was performed, measuring the responses for the spermatic ducts (SD), bladder neck (BN), and prostate contraction, by stimulating the right lumbar splanchnic nerves (LSNs) from L2 to L4, after transection of the left HGN to eliminate substitutive pathways.

RESULTS

Two months after implantation, the regenerated neurofilaments were successfully extended through the graft from the proximal-to-distal direction. In 2 control dogs, electrostimulation of the right LSNs induced elevation of the intraluminal pressure of the SD, elevation of the BN pressure, and prostate contraction. No responses were observed in all dogs up to 6 months of follow-up after implantation. In 1 dog with a 7-month follow-up, electrostimulation elicited elevation of BN pressure alone. In both dogs with an 8-month follow-up, electrostimulation induced similar responses to control in all SD, BN, and prostate; however, after excision of the area of the interposed right HGN, no response was observed.

CONCLUSIONS

These results proved that regeneration of a 10-mm gap of the HGN, using a novel PGA-collagen nerve conduit could be achieved within 8 months.

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.

Impact of unilateral sural nerve graft on recovery of potency and continence following radical prostatectomy: 3-year longitudinal study

PURPOSE

We conducted a 3-year longitudinal study assessing the impact of unilateral sural nerve graft on recovery of potency and continence following radical prostatectomy.

MATERIALS AND METHODS

A total of 113 patients undergoing radical retropubic prostatectomy were classified into 3 groups according to the degree of nerve sparing, that is unilateral nerve preservation with contralateral sural nerve graft interposition, bilateral nerve sparing and unilateral nerve sparing. Urinary continence and potency were estimated by the UCLA Prostate Cancer Index questionnaire.

RESULTS

Patients in the nerve sparing plus sural nerve graft group were younger than those in the bilateral nerve sparing or unilateral nerve sparing groups. At baseline the unilateral nerve sparing plus sural nerve graft group and the bilateral nerve sparing group reported better sexual function than the unilateral nerve sparing group (62.1 and 61.5 vs 49.9, p<0.05). The bilateral nerve sparing group showed more rapid recovery than the unilateral nerve sparing plus sural nerve graft group after radical retropubic prostatectomy (p<0.01). After 24 months there were no significant differences observed between the bilateral nerve sparing and the unilateral nerve sparing plus sural nerve graft group (28.7 vs 32.9). The bilateral nerve sparing group reported a better sexual function score than the unilateral nerve sparing group throughout the postoperative period (p<0.05). The bilateral nerve sparing group maintained significantly better urinary function at 1 month after radical retropubic prostatectomy than the unilateral nerve sparing plus sural nerve graft group (p <0.05). After 3 months these groups were almost continent. The unilateral nerve sparing group reported lower urinary function scores during the first year compared to the other groups.

CONCLUSIONS

The nerve graft procedure may contribute to the recovery of urinary function as well as sexual function after radical retropubic prostatectomy. This finding needs to be validated in a randomized trial.

Analysis of Risk Factors for Urinary Incontinence after Radical Prostatectomy

INTRODUCTION

Our aim was to identify the independent risk factors associated with urinary incontinence after radical retropubic prostatectomy (RRP).

MATERIALS AND METHODS

Using univariate and multivariate analyses, we examined several pre- and perioperative factors. One hundred and sixty-six patients were divided into three groups: patients who were immediately continent after catheter removal (group I), patients who became continent later (group II) and incontinent patients (group III).

RESULTS

There were 34 patients (20.5%) in group I, 111 (66.9%) in group II, and 21 (12.6%) in group III. The multivariate analysis between the continent and incontinent patients proved that the postoperatively measured total length of the posterior urethra (strongly associated with length of the sphincter, length of the urethral stump and the presence of anastomotic stricture) was the independent risk factor for permanent incontinence or delayed continence following RRP. The age of patients per se represented a risk factor only for delayed continence, but not for permanent incontinence.

CONCLUSIONS

Postoperatively measured shorter posterior urethral length results in an increased risk of urinary incontinence and delays continence after RRP. It seems that older age only delays reaching continence.

Bilateral Cavernous Nerve Interposition Grafting During Radical Retropubic Prostatectomy: Memorial Sloan-Kettering Cancer Center Experience

PURPOSE

Cavernous nerve graft is an option for men requiring bilateral cavernous nerve resection for cancer control during radical prostatectomy. We determined the success rate and identified determinants of success of bilateral cavernous nerve grafting following resection of the 2 nerves during radical prostatectomy in patients who were potent preoperatively.

MATERIALS AND METHODS

We retrospectively reviewed the records of 44 consecutive patients who underwent bilateral nerve grafting from 1999 to 2004. Postoperative erectile function was defined as the achievement of erections satisfactory for intercourse with or without oral medication. We calculated cumulative erectile function recovery rates using Kaplan-Meier curves. The log rank test was used to compare variables affecting erectile function recovery with p <0.0083 considered significant after adjusting for the number of variables evaluated using the Bonferroni correction.

RESULTS

The overall 5-year cumulative recovery of erectile function permitting penetration was 34% and the rate of consistent penetration was 11%. None of the analyzed variables were significantly associated with recovery of postoperative erectile function, including patient age (p = 0.3), incomplete bilateral cavernous nerve resection (p = 0.045), sural nerve grafts compared to genitofemoral or ilioinguinal nerves as donor sites (p = 0.067), post-radiation salvage radical prostatectomy (p = 0.15), neoadjuvant hormone therapy (p = 0.7) and comorbidities (p = 0.15) or medications (p = 0.4) affecting EF.

CONCLUSIONS

Bilateral cavernous nerve grafts might be beneficial in select patients. A definitive answer awaits the performance of a multi-institutional, randomized, controlled trial.

Hope springs eternal: cavernosal nerve regeneration

Erectile dysfunction after radical prostatectomy for prostate cancer remains a significant morbidity for a large group of patients. A large body of work suggests that disrupting the cavernosal nerves is central as a causative factor. Extensive research has focused on ways to increase potency rates after surgery, either by preserving neuro-integrity, or attempting to restore it using various approaches. Herein we discuss the neurophysiology of nerve injury and regeneration, and review the work to date on cavernosal nerve regeneration.

Urinary incontinence and voiding dysfunction after radical retropubic prostatectomy (prospective urodynamic study)

AIMS

During this prospective study we analyzed the effects of radical retropubic prostatectomy (RRP) on bladder and sphincter function by comparing preoperative and postoperative urodynamic data. The aim of the study was to determine the reason for urinary incontinence after RRP and explain why one group of patients will be immediately continent after catheter removal, while others need some time to reach complete continence.

METHODS

Urodynamic examination was performed in 63 patients 3-7 days before and 2 months after surgery.

RESULTS

Forty-three (68.2%) and 53 (84.1%) patients regained continence at 2 and 9 months following RRP, respectively. Ten patients (15.9%) were immediately continent after catheter removal. Urodynamic stress incontinence was detected in 18 (28.6%), and detrusor overactivity incontinence in 2 (3.2%) patients 2 months after surgery. The amplitude of preoperative maximal voluntary sphincteric contractions was significantly higher in the postoperative continent group (125 vs. 96.5 cmH(2)O, P < 0.0001). The patients who were immediately continent following catheter removal had no lower urinary tract symptoms (LUTS) and urodynamic abnormality preoperatively, and they had significantly higher preoperative and postoperative maximum urethral closure pressure (at rest and during voluntary sphincter contraction) than those who became continent later on.

CONCLUSIONS

These data suggest that the main cause of incontinence after RRP is sphincteric weakness. In the continent group, those who became immediately continent had significantly higher maximum urethral closure pressure values at rest and at voluntary sphincteric contraction even before the surgery.