Current status of penile rehabilitation after radical prostatectomy

Global research trends on the links between prostate cancer and erectile dysfunction between 2003 and 2023: A bibliometrics and visualized study

Background

The incidence of prostate cancer (PC) has increased in recent years. Erectile dysfunction (ED) after prostate cancer treatment has aroused extensive attention. Bibliometric analysis was designed to investigate a systematic understanding of developments between PC and ED during the past 20 years.

Methods

Literatures on PC and ED were retrieved from the Web of Science Core Collection database (WoSCC). By using the VOS viewer and CiteSpace software to analysis the metrics of bibliometric literature, such as number of articles, journals, countries, institutions, authors, keywords and associated information. The number of publications per year was statistically analysed and plotted thorough Microsoft Office. In addition, Pajek software was used to adjust the visual map.

Results

A total of 2332 screened articles were included in the analysis. The Journal of Sexual Medicine, ranking first among the analysed journals, published 235 articles. The United States and Canada were leaders in PC and ED research. There is a need to strengthen inter-agency cooperation in this area of research on a global scale. Mulhall JP, as the most prolific author in this area of research, published 80 articles. And Rosen RC was the author with the most co-citated (693 co-citated). The main research focus on the prevention, treatment and management of ED after PC treatment in this field through the keyword analysis.

Conclusions

Research on PC and ED is expected to expand further worldwide. We found ED, as new sustainable treatment modalities, scientific postoperative management and psychological interventions for patients, may become the research hotspots and should be closely concerned in this study.

Comparison of the efficacy of the early LI-SWT plus daily tadalafil with daily tadalafil only as penile rehabilitation for postprostatectomy erectile dysfunction

This study compares the efficacy of the early low-intensity shock wave therapy (LI-SWT) plus daily tadalafil with daily tadalafil only therapy as penile rehabilitation for postprostatectomy erectile dysfunction in patients with prostate cancer who underwent bilateral interfascial nerve-sparing radical prostatectomy (robotic or open). From April 2019 to March 2021, 165 patients were enrolled, and 80 of them successfully completed this prospective study. Daily tadalafil were administered to all the patients. LI-SWT consisted of a total of six sessions. Each session was performed on days 4, 5, 6, and 7, and on the second and fourth weeks after surgery. Each LI-SWT session consisted of 300 shocks at an energy density of 0.09 mJ/mm2 and a frequency of 120 shocks per minute that were delivered at each of the five treatment points for 15 min. Thirty-nine patients were treated with tadalafil-only (group A) while 41 were treated with tadalafil and LI-SWT simultaneously (group B). At postoperative 6 months, the proportion of patients with erection hardness scores (EHS) ≥ 3 (4/39 vs. 12/41) was significantly higher in group B (p = 0.034), and LI-SWT was the only independent factor for predicting EHS ≥ 3 (OR, 3.621; 95% CI, 1.054-12.437; p = 0.041). There were no serious side effects related to early LI-SWT. Early LI-SWT plus daily tadalafil therapy as penile rehabilitation for postprostatectomy erectile dysfunction is thought to be more efficacious than tadalafil only. Further large-scaled randomized controlled trials will be needed to validate these findings.

Sexual rehabilitation with intracavernous alprostadil after radical prostatectomy: Outcomes from a nursing program

INTRODUCTION AND OBJECTIVES

Erectile dysfunction (ED) is a common complication after radical prostatectomy that affects quality of life. There are several therapeutic options, including intracavernous alprostadil injections (IAI). However, no specific recommendations have been made on the optimal rehabilitation strategy. In this study we evaluated a sexual rehabilitation program (SRP) with IAI for patients with ED after radical prostatectomy, assessing the rate of compliance and reasons for dropout.

METHODS

The sexual rehabilitation program (SRP) was offered to all patients who underwent radical prostatectomy from 1 January 2010 to 31 December 2019. The first consultations were performed by a urology specialist nurse, explaining the IAI procedure and possible complications. The program was considered successful when the patients achieved autonomy in the drug preparation with a good injection technique. A medical consultation was performed at 6 months evaluating the IAI usage and adverse events. In case of dropout, a questionnaire about reasons for dropout was performed. The primary endpoint was the rate of compliance and dropout of the program. Secondary endpoints were the reasons for dropout and adverse events.

RESULTS

340 patients underwent radical prostatectomy at our institution, and 123 patients accepted to participate in the rehabilitation program. A total of 96 patients (78%) successfully completed the SRP, and at 6 months 60 (62.5%) still used IAI. Concerning the reasons for dropping out, the most frequent were the need of injectable therapy and pain. Regarding complications, 17 patients (13.8%) reported pain related to the injection and 1 patient (0.8%) had a priapism, managed with conservative treatment.

CONCLUSIONS

Management of post-radical prostatectomy ED by a nursing program achieved good rates of patients' self-injection accomplishment and treatment compliance. Close monitoring for dose adjustment and management of post-injection penile pain is required during the follow-up.

Sexual rehabilitation recommendations for prostate cancer survivors and their partners from a biopsychosocial Prostate Cancer Supportive Care Program

PURPOSE

This study aimed to highlight the biopsychosocial recommendations provided to prostate cancer survivors and their partners during sexual rehabilitation.

METHODS

Retrospective analysis of a prospectively maintained patient database was conducted for visits between 2013 and 2019. The sexual health rehabilitation action plan (SHRAP) is a standardized 29-item list of biopsychosocial recommendations. The frequency of biopsychosocial recommendations provided to patients via their SHRAPs was assessed.

RESULTS

Among 913 patients, across 2671 appointments, nearly 74% of patients underwent radical prostatectomy. Other treatments included combination therapy (surgery, radiation, and/or androgen deprivation therapy (ADT)) (13%), radiation (external beam radiation or brachytherapy) (5%), and active surveillance (2%). Each patient had a median of 2 (SD 2.06) appointments and received a mean of 10.0 (SD 3.9) recommendations at each visit. Educational recommendations (penile rehabilitation, orgasmic guidelines, and climacturia management) were provided in 84% of visits followed by psychosexual recommendations (pleasure-focused, dedicated time, simmering, sexual aids, and sensate focus) in 71% of all appointments. The top recommendations (total n, frequency of recommendation) were penile rehabilitation (2253, 84%), pleasure-focus (1887, 71%), phosphodiesterase inhibitors (1655, 62%), clinical counselor (1603, 60%), vacuum erectile device (1418, 53%) and intracavernosal injections (1383, 52%).

CONCLUSIONS

Biopsychosocial programs are evolving to be a key part of prostate cancer survivorship. This study's insight suggests that prostate cancer survivors require education around their sexual consequences and psychosexual counseling alongside proven biomedical strategies for erectile dysfunction.

IMPLICATIONS FOR CANCER SURVIVORS

Cancer survivorship programs should integrate educational and psychosocial strategies alongside biological strategies for prostate cancer survivors and their partners.

Pelvic Floor Muscle Training and Erectile Dysfunction in Radical Prostatectomy: A Randomized Controlled Trial Investigating a Non-Invasive Addition to Penile Rehabilitation

INTRODUCTION

Pelvic floor muscle (PFM) training for postprostatectomy incontinence is considered a first line approach to rehabilitation, but PFM training for erectile dysfunction (ED) after surgery is less well known. With more than 1.4 million new cases diagnosed globally per year, there is a need for non-invasive options to assist sexual dysfunction recovery.

AIM

Commencing preoperatively and using both fast and slow twitch fibre training performed in standing postures, new protocols were developed to address clinical presentations with aims to reduce ED and impact on quality of life (QoL). Comparisons with "usual care" PFM training, prerehabilitation and postrehabilitation were then assessed.

METHODS

A randomised controlled trial of 97 men undergoing radical prostatectomy (RP) were allocated to either a control group (n = 47) performing "usual care" of 3 sets/d PFMT or an intervention group (n = 50), performing 6 sets/d in standing, commencing 5 weeks before RP.

OUTCOME MEASURES

Participants were assessed preoperatively and at 2, 6, and 12 weeks after RP using the Expanded Prostate Cancer Index Composite for Clinical Practice, International Index of Erectile Function-5, and real time ultrasound measurements of PFM function.

RESULTS

At all time points, there was a significant difference (P< 0.05) between groups; however, the only time point where this difference was clinically relevant was at 2 weeks after RP, with the intervention group reporting less distress in the Expanded Prostate Cancer Index Composite for Clinical Practice QoL outcome. Secondary measures of EPIC-EF and real time ultrasound PFM function tests demonstrated improvement over all time points in both groups with lower bothersome scores in the intervention group.

CONCLUSIONS

Early PFM training reduces early QoL impact for postprostatectomy ED, with faster return to continence enabling earlier commencement of penile rehabilitation. While our 12-week protocol and sample size was not powerful enough to demonstrate conclusive benefits of early PFM training for ED, PFM intervention after RP over longer times has been supported by others. Milios JE, Ackland TR, Green DJ. Pelvic Floor Muscle Training and Erectile Dysfunction in Radical Prostatectomy: A Randomized Controlled Trial Investigating a Non-Invasive Addition to Penile Rehabilitation. J Sex Med 2020;8:414-421.

Pericyte-Derived Extracellular Vesicle-Mimetic Nanovesicles Restore Erectile Function by Enhancing Neurovascular Regeneration in a Mouse Model of Cavernous Nerve Injury

BACKGROUND

Extracellular vesicle (EV)-mimetic nanovesicles (NVs) from embryonic stem cells have been observed to stimulate neurovascular regeneration in the streptozotocin-induced diabetic mouse. Pericytes play important roles in maintaining penile erection, yet no previous studies have explored the effects of pericyte-derived NVs (PC-NVs) in neurovascular regeneration in the context of erectile dysfunction.

AIM

To investigate the potential effect of PC-NVs in neurovascular regeneration.

METHODS

PC-NVs were isolated from mouse cavernous pericytes, and neurovascular regeneration was evaluated in an in vitro study. Twelve-week-old C57BL/6J mice were used to prepare cavernous nerve injury model. Erectile function evaluation, histologic examination of the penis, and Western blots were assessed 2 weeks after model creation and PC-NVs treatment.

OUTCOMES

The main outcomes of this study are PC-NVs characterization, intracavernous pressure, neurovascular regeneration in the penis, and in vitro functional evaluation.

RESULTS

The PC-NVs were extracted and characterized by cryotransmission electron microscopy and EV-positive (Alix, TSG101, CD81) and EV-negative (GM130) markers. In the in vivo studies, PC-NVs successfully improved erectile function in cavernous nerve injury mice (∼82% of control values). Immunofluorescence staining showed significant increases in pericytes, endothelial cell, and neuronal contents. In the in vitro studies, PC-NVs significantly increased mouse cavernous endothelial cells tube formation, Schwann cell migration, and dorsal root ganglion and major pelvic ganglion neurite sprouting. Finally, Western blot analysis revealed that PC-NVs upregulated cell survival signaling (Akt and eNOS) and induced the expression of neurotrophic factors (brain-derived neurotrophic factor, neurotrophin-3, and nerve growth factor).

CLINICAL IMPLICATIONS

PC-NVs may be used as a strategy to treat erectile dysfunction after radical prostatectomy or in men with neurovascular diseases.

STRENGTHS & LIMITATIONS

We evaluated the effect of PC-NVs in vitro and in a mouse nerve injury model, cavernous nerve injury. Additional studies are necessary to determine the detailed mechanisms of neurovascular improvement. Further study is needed to test whether PC-NVs are also effective when given weeks or months after nerve injury.

CONCLUSION

PC-NVs significantly improved erectile function by enhancing neurovascular regeneration. Local treatment with PC-NVs may represent a promising therapeutic strategy for the treatment of neurovascular diseases. Yin GN, Park S-H, Ock J, et al. Pericyte-Derived Extracellular Vesicle-Mimetic Nanovesicles Restore Erectile Function by Enhancing Neurovascular Regeneration in a Mouse Model of Cavernous Nerve Injury. J Sex Med 2020;17:2118-2128.

Advanced Penile Length Restoration Techniques to Optimize Penile Prosthesis Placement Outcomes

INTRODUCTION

The most common cause of patient dissatisfaction after penile prosthesis placement is penile shortening compared with one's memory of a natural erection. Surgical techniques as well as preoperative and postoperative protocols have been reported to preserve and possibly enhance penile length in someone undergoing penile prosthesis surgery.

OBJECTIVES

This article presents a description of as well as the authors' experience with presurgical protocols, intraoperative techniques, and postsurgical protocols that allow for preservation or enhancement of penile length for patients who undergo inflatable penile prosthesis insertion.

METHODS

An extensive, systematic literature review was performed using PubMed searching for key terms including penile lengthening, inflatablepenile prosthesis, penile girth, buried penis, and penile enhancement. All articles with subjective and/or objective penile length outcomes were reviewed.

RESULTS

Several preoperative treatment protocols were found for penile length preservation and enhancement, which included use of a vacuum erection device as well as traction therapy. Intraoperative techniques included cavernosal sparing, channeling without dilatation, circumferential penile degloving, ventral phalloplasty, suprapubic lipectomy, liposuction, suspensory ligament release, sliding technique, modified sliding technique, multislice technique, and aggressive implant sizing. Postoperative protocols included early device inflation and cycling. Table 1 summarizes and compares the various preoperative, intraoperative, and postoperative strategies identified during literature review with their corresponding reported length gain.

CONCLUSIONS

Many preoperative, intraoperative, and postoperative surgical techniques can be performed by high-volume implanters to improve one's perceived or true penile length. In the hands of experienced, high-volume implanters, these techniques can be very meaningful for patients undergoing penile prosthesis insertion, particularly those who are concerned with penile length. Shah B, Kent M, Valenzuela R. Advanced Penile Length Restoration Techniques to Optimize Penile Prosthesis Placement Outcomes. Sex Med Rev 2020;XX:XXX-XXX.

Smooth Muscle Progenitor Cells Preserve the Erectile Function by Reducing Corporal Smooth Muscle Cell Apoptosis after Bilateral Cavernous Nerve Crush Injury in Rats

Radical prostatectomy causes erectile dysfunction (ED) and irreversible morphologic changes, including induction of endothelial and smooth muscle cell (SMC) apoptosis in the corpus cavernosum (CC). The injection of smooth muscle progenitor cells (SPCs) thickens the vascular intima and has demonstrated therapeutic benefit in cardiovascular disease animal. Herein, we investigated the effect of SPCs on the recovery of erectile function (EF) in rat models with bilateral cavernous nerve (CN) injury. Twenty-four male Sprague-Dawley rats were randomized into sham, vehicle only, or SPC treatment groups. Rats in the SPC treatment and vehicle groups were subjected to bilateral CN injury before intracavernosal injection. Intracavernosal injections of SPCs increased all EF parameters at day 28 after injury and simultaneously reduced apoptosis of the SMCs. Ultrastructural analysis revealed that SPCs maintained the integrity of the CC by preserving the structure of the adherens junctions. Tracking transplanted SPCs labeled with EdU showed that transplanted SPCs remained in the CC 28 days after treatment. Intracavernosal SPC injection restored EF after bilateral CN injury by reducing SMC apoptosis, which favored the maintenance of the structure of adherens junctions and regulated the stability of corporal vessels. These findings demonstrate the therapeutic potential of SPCs for treating ED in humans.

Penile rehabilitation after nerve-sparing prostatectomy: Fact or fiction?

A 65-year-old man is seen in the clinic two months after a robot-assisted bilateral nerve-sparing radical prostatectomy. He is completely continent and has been since the catheter was removed. The main reason for his referral is erectile dysfunction. Pre-operatively his SHIM score was 25 (maximum score 25). He currently experiences some thickening with stimulation, and an erection hardness score of 2. He has a pleasurable sensation of orgasm during which he remains dry. His sex drive remains normal. He has a long-standing history of hypertension and raised LDL cholesterol, managed with amlodipine and simvastatin respectively. He has no other overt cardiovascular or ischaemic heart disease, and he is not a diabetic, but has an elevated fasting glucose of 6.0 mmol per litre. He stopped smoking five years ago, is 5 feet 11 inches tall, a weight of 95 kg, has a waist measurement of 44 inches (BMI 29 – upper end of overweight) (range <18.50 underweight; 18.50–24.99 healthy weight; 25.00–29.99 overweight; >30.00 obese). He performs no regular exercise. His wife is 60. He is keen to try to regain his erectile function.

Maintenance of the contractile phenotype in corpus cavernosum smooth muscle cells by Myocardin gene therapy ameliorates erectile dysfunction in bilateral cavernous nerve injury rats

The pathophysiology of erectile dysfunction post radical prostatectomy is not clearly clarified, and the low efficacy of traditional PDE5i treatment remains a major complaint in contemporary practice. This study aimed to demonstrate phenotypic modulation in bilateral cavernous nerve injury (BCNI) rats within 7 days, and subsequently validate gene therapy with Myocardin (Mycod) by maintaining a contractile phenotype in corpus cavernosum smooth muscle cells. Initially, 36 male rats were randomly divided into BCNI and negative control (NC) groups for histological and phenotypic molecular measurements at 3, 5, and 7 days. Afterwards, an additional 30 rats received a single intra-cavernous injection of 50 μL PBS, Ad-Myocd (1 × 1011  pfu/ml) or Ad-vector for 10 animals each, namely the NC+PBS, BCNI+Ad-Myocd, and BCNI+Ad-vector groups. Finally, the validity and mechanism of Myocd transfection was explored at 21 days in vivo and 48 h in vitro. Western blotting showed canonical declines in Myocd, α-SMA, and Calponin expression, as well as elevated Osteopontin (OPN) expression, before corporeal morphological and SM-to-collagen ratio changes at day 5 after injury. Overexpression of Myocd maintained the contractile phenotype of corpus cavernosum smooth muscle cells, ameliorated bilateral cavernous nerve injury rat erectile dysfunction, as well as promoted cell contractility and suppressed proliferative capacity. Simultaneously, confocal imaging revealed up-regulation and co-localization of serum response factor in gene-transferred cells. In conclusion, our study is the first to investigate corpus cavernosum smooth muscle cells phenotypes in the early stages of cavernous injury model rats, and Myocd reversed phenotypic modulation by activating serum response factor. The experimental results demonstrated the validity of gene therapy for erectile dysfunction.

Antioxidative mechanism of Lycium barbarum polysaccharides promotes repair and regeneration following cavernous nerve injury

Polysaccharides extracted from Lycium barbarum exhibit antioxidant properties. We hypothesized that these polysaccharides resist oxidative stress-induced neuronal damage following cavernous nerve injury. In this study, rat models were intragastrically administered Lycium barbarum polysaccharides for 2 weeks at 1, 7, and 14 days after cavernous nerve injury. Serum superoxide dismutase and glutathione peroxidase activities significantly increased at 1 and 2 weeks post-injury. Serum malondialdehyde levels decreased at 2 and 4 weeks. At 12 weeks, peak intracavernous pressure, the number of myelinated axons and nicotinamide adenine dinucleotide phosphate-diaphorase-positive nerve fibers, levels of phospho-endothelial nitric oxide synthase protein and 3-nitrotyrosine were higher in rats administered at 1 day post-injury compared with rats administered at 7 and 14 days post-injury. These findings suggest that application of Lycium barbarum polysaccharides following cavernous nerve crush injury effectively promotes nerve regeneration and erectile functional recovery. This neuroregenerative effect was most effective in rats orally administered Lycium barbarum polysaccharides at 1 day after cavernous nerve crush injury.

A Phase 3 Study to Evaluate the 1-Year Efficacy and Safety of Udenafil 75 mg Once Daily in Patients With Erectile Dysfunction

INTRODUCTION

Once-daily administration of phosphodiesterase type 5 inhibitors has been shown to correct erectile dysfunction (ED).

AIM

To evaluate the long-term efficacy and safety after once-daily oral administration of udenafil 75 mg in men with ED.

METHODS

This clinical trial was an open-label, fixed-dose, 24-week extension study (DA8159_EDDL_III) of a 24-week double-blinded efficacy and safety study of once-daily udenafil (parent study: DA8159_EDD_III). Subjects received udenafil 75 mg once daily for 24 weeks during this extension study, and the follow-up visit occurred during the 4-week ED treatment-free period.

MAIN OUTCOME MEASURES

Subjects were asked to complete the International Index of Erectile Function questionnaire and the Global Assessment Questionnaire at the 24-week extension and after the 4-week ED treatment-free period, and the development of adverse drug reactions was investigated.

RESULTS

In total, 302 subjects were enrolled in this extension study. Improvement was shown with an increased erectile function (EF) domain score compared with baseline (14.60 ± 4.57) at extension week 48 (23.98 ± 5.44) and a slight increase in EF domain score compared with the last time point (week 24) of the parent study (P < .001). The Global Assessment Questionnaire showed a high improvement rate of 95.4% at the extension 48-week time point. For shift to normal, almost half the subjects (45.1%) recovered "normal" EF, and 14.2% of subjects reported normal erections after the 4-week ED treatment-free period. The occurrence rate of adverse drug reactions was 8%, which consisted mainly of flushing and headache.

CONCLUSION

Once-daily dosing of udenafil 75 mg showed excellent efficacy and safety with long-term administration and allowed a more spontaneous sexual life.

Restoration of erectile function with intracavernous injections of endothelial progenitor cells after bilateral cavernous nerve injury in rats

Endothelial progenitor cells (EPCs) are bone marrow-derived endothelial cells capable of circulating, proliferating, and differentiating into mature endothelial cells. Circulating EPCs can be directly recruited to some extent at sites of injury, and their administration could accelerate repair or endothelialization of the damaged tissue. We investigated the effects of intracavernous injections of EPCs into the corpora cavernosa of rats with erectile dysfunction (ED) caused by bilateral cavernous nerve (CN) injury. Overall, 24 male Sprague-Dawley rats were randomized into three groups: sham surgery, vehicle-only, or EPC treatment. Rats in the EPC treatment and vehicle-only groups were subjected to bilateral CN injury before injection of EPCs or vehicle, respectively, into the corpora cavernosa. Four weeks after surgery, erectile function was assessed by measuring maximum intracavernosal pressure (ICP), change in ICP, area under the ICP curve, and ratio of change in ICP and mean arterial pressure (MAP; ΔICP/MAP). Penile tissue was histomorphometrically analyzed for the expression of neural nitric oxide synthase (nNOS), neurofilament-1 (NF-1), von Willebrand factor (vWF), endothelial NOS (eNOS), and smooth muscle cell content. Maximum ICP and all other functional parameters of erectile function were significantly reduced in the vehicle-only group vs. the sham and EPC treatment groups (all p < 0.001). Smooth muscle cell content was decreased in the vehicle-only vs. the sham and EPC treatment groups (both p < 0.01). Expressions of vWF and eNOS in the dorsal artery were significantly higher in the EPC treatment than the vehicle-only group (p < 0.05). In conclusion, EPC treatment restored erectile function in a rat model of bilateral CN injury through recruitment of EPCs toward the dorsal artery and preservation of smooth muscle cells in the corpus cavernosum. These findings elucidate the therapeutic potential of EPCs for treating ED in humans.

Light-controlled relaxation of the rat penile corpus cavernosum using NOBL-1, a novel nitric oxide releaser

Purpose

To investigate whether relaxation of the rat penile corpus cavernosum could be controlled with NOBL-1, a novel, light-controllable nitric oxide (NO) releaser.

Materials and Methods

Fifteen-week-old male Wistar-ST rats were used. The penile corpus cavernosum was prepared and used in an isometric tension study. After noradrenaline (10^-5 M) achieved precontraction, the penile corpus cavernosum was irradiated by light (470–500 nm) with and without NOBL-1 (10^-6 M). In addition, we noted rats' responses to light with vardenafil (10^-6 M), a phosphodiesterase-5 (PDE-5) inhibitor. Next, responses to light in the presence of a guanylate cyclase inhibitor, ODQ (1H-[1,2,4] oxadiazolo[4,3-a]quinoxalin-1-one) (10^-5 M), were measured. All measurements were performed in pretreated L-NAME (10^-4 M) conditions to inhibit endogenous NO production.

Results

Corpus cavernosal smooth muscle, precontracted with noradrenaline, was unchanged by light irradiation in the absence of NOBL-1. However, in the presence of NOBL-1, corpus cavernosal smooth muscle, precontracted with noradrenaline, relaxed in response to light irradiation. After blue light irradiation ceased, tension returned. In addition, the light response was obviously enhanced in the presence of a PDE-5 inhibitor.

Conclusions

This study showed that rat corpus cavernosal smooth muscle relaxation can be light-controlled using NOBL-1, a novel, light sensitive NO releaser. Though further in vivo studies are needed to investigate possible usefulness, NOBL-1 may be prove to be a useful tool for erectile dysfunction therapy, specifically in the field of penile rehabilitation.