Overview of contemporary penile rehabilitation therapies

The science of vacuum erectile device in penile rehabilitation after radical prostatectomy

INTRODUCTION

Radical prostatectomy (RP) is a standard surgical treatment for clinically localized prostate cancer. Erectile dysfunction (ED) and penile shrinkage are common complications. Vacuum Erectile Device (VED) therapy uses negative pressure to distend the corporal sinusoids and to increase blood inflow into the penis. It is the second most commonly used method for penile rehabilitation after RP. However, the underlying mechanisms are still unclear. This paper is designed to review the scientific evidences of VED therapy after RP and discuss the possible mechanisms.

METHODS

We reviewed published papers of post-prostatectomy penile rehabilitation using VED. We analyzed the scientific evidences of VED therapy and discussed the possible underlying mechanisms.

RESULTS

There are existing clinical evidences for VED therapy to improve ED and preserve penile size. Emerging basic scientific evidence is available and further study is still needed to understand the mechanisms at the molecular level.

CONCLUSIONS

Current clinical evidences support the safety, tolerability, effectiveness and benefits of early VED therapy after RP. The available basic scientific evidences demonstrate that VED therapy for penile rehabilitation is achieved by increasing arterial inflow, anti-apoptotic, anti-fibrotic and anti-hypoxia mechanisms.

Early postoperative pelvic-floor biofeedback improves erectile function in men undergoing radical prostatectomy: a prospective, randomized, controlled trial

Erectile dysfunction (ED) and urinary incontinence are common complications following radical prostatectomy (RP). Although pelvic-floor biofeedback training (PFBT) may improve urinary continence following RP, its effects on the recovery of potency are unknown. Fifty-two patients selected for RP were prospectively randomized for a treatment group (n=26) receiving PFBT once a week for 3 months and home exercises or a control group (n=26), in which patients received verbal instructions to contract the pelvic floor. Erectile function (EF) was evaluated with the International Index of Erectile Function-5 (IIEF-5) before surgery and 1, 3, 6 and 12 months postoperatively. Patients were considered potent when they had a total IIEF-5 score>20. Continence status was assessed and defined as the use of no pads. Groups were comparable in terms of age, body mass index, diabetes, pathological tumor stage and neurovascular bundle preservation. A significant reduction in IIEF-5 scores was observed after surgery in both groups. In the treatment group, 8 (47.1%) patients recovered potency 12 months postoperatively, as opposed to 2 (12.5%) in the control group (P=0.032). The absolute risk reduction was 34.6% (95% confidence interval (CI): 3.8-64%) and the number needed to treat was 3 (95% CI: 1.5-17.2). A strong association between recovery of potency and urinary continence was observed, with continent patients having a 5.4 higher chance of being potent (P=0.04). Early PFBT appears to have a significant impact on the recovery of EF after RP. Urinary continence status was a good indicator of EF recovery, with continent patients having a higher chance of being potent.

Molecular mechanisms of vacuum therapy in penile rehabilitation: a novel animal study

BACKGROUND

Penile rehabilitation (PR) is widely applied after radical prostatectomy. Vacuum erectile device (VED) therapy is the one of three PR methods used in the clinical setting that improve erectile function (EF) and is the only PR method which may preserve penile length. However, its unknown mechanism hampered doctors' recommendations and patients' compliance.

OBJECTIVES

To assess the effects of VED therapy on erectile dysfunction (ED) in a rat model of bilateral cavernous nerve crush (BCNC) and to investigate the molecular mechanism of VED in postprostatectomy ED.

DESIGN, SETTING, AND PARTICIPANTS

This was an experimental study using Sprague-Dawley rats in three groups: sham, BCNC, and BCNC plus VED.

INTERVENTION

Intervention included BCNC, electrical stimulation of the cavernous nerve (CNS), and VED therapy.

MEASUREMENTS

At the end of a 4-wk period, CNS was used to assess EF by maximum intracavernosal pressure (ICP)/mean arterial pressure (MAP) ratio and duration (area under the curve [AUC]). For the structural analyses, whole rat penis was harvested. Terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling assay was used for the assessment of apoptotic indices (AI). Immunohistochemistry was performed for endothelial nitric oxide synthase (eNOS), α-smooth muscle actin (ASMA), transforming growth factor beta 1 (TGF-β1), and hypoxia inducible factor-1α (HIF-1α). Staining for Masson's trichrome was utilized to calculate the smooth muscle/collagen ratios.

RESULTS AND LIMITATIONS

EF was improved with VED therapy measured by ICP/MAP ratios and AUC. VED therapy reduced HIF-1α expression and AI significantly compared with control. Animals exposed to VED therapy had decreased TGF-β1 expression, increased smooth muscle/collagen ratios, and preserved ASMA and eNOS expression.

CONCLUSIONS

To our knowledge, this is the first scientific study to suggest that VED therapy in the BCNC rat model preserves EF through antihypoxic, antiapoptotic, and antifibrotic mechanisms.

Vacuum therapy in erectile dysfunction--science and clinical evidence

Vacuum therapy (VT) utilizes negative pressure to distend the corporal sinusoids and to increase the blood inflow to the penis. Depending on its purpose, VT could be used as vacuum constriction device (VCD), with the aid of an external constricting ring which is placed at the base of penis to prevent blood outflow, maintaining the erection for sexual intercourse. Also, as a vacuum erectile device (VED), without the application of a constriction ring, just increases blood oxygenation to the corpora cavernosa and for other purposes. The emerging of phosphodiesterase 5 inhibitors (PDE(5)I) for the treatment of erectile dysfunction (ED) eclipsed VCD as therapeutic choice for ED; however, widespread usage of VED as part of penile rehabilitation after radical prostatectomy and other purposes rekindle the interest for VT. The underlying hypothesis is that the artificial induction of erections shortly after surgery facilitates tissue oxygenation, reducing cavernosal fibrosis in the absence of nocturnal erections, and potentially increases the likelihood of preserving erectile function. Due to its ability to draw blood into the penis regardless of nerve disturbance, VED has become the centerpiece of penile rehabilitation protocols. Herein, we reviewed the history, mechanism, application, side effects and future direction of VT in ED.