CAVERNOUS ARTERIAL AND ARTERIOLAR CIRCULATION IN PATIENTS WITH ERECTILE DYSFUNCTION: A POWER DOPPLER STUDY

Purpose

We assessed the morphodynamic features of cavernous arteries and helicine arterioles by power Doppler sonography in vasculogenic and nonvasculogenic impotent men.

Materials and Methods

A total of 40 impotent patients with and without definite vascular risk factors were studied by penile power Doppler sonography. The test was performed during penile flaccidity, after intracavernous injection of 20 mcg. alprostadil and after subsequent genital and audiovisual sexual stimulation. A second injection and stimulation were given if the erectile response observed after the initial injection was less than the maximum erection seen during sexual activity. Morphodynamic parameters evaluated by power Doppler imaging included vessel course, shape, wall thickness and pulsatility, peak systolic velocity, end diastolic velocity, acceleration time and resistance index.

Results

In the nonvasculogenic group all patients who achieved rigid erection showed normal cavernosal artery and helicine arteriole inflow. In these cases the arteriolar picture was characterized by the presence of 3 orders of distal ramifications originating from the cavernous arteries with an acute angle, systolic diastolic flow during penile tumescence and systolic flow alone at full rigidity. In the vasculogenic group patients with normal cavernous artery inflow showed an arteriolar tree that was pathological in 50% and was characterized by a reduced number of ramifications originating perpendicularly from the cavernous arteries and irregular caliber (arteriolar impotence). In the same group patients with reduced cavernous artery inflow also showed normal or pathological arteriolar components (pre-penile arterial impotence and diffused penile arterial impotence).

Conclusions

Power Doppler sonography allows a precise study of the morphodynamics of the cavernous arteries and helicine arterioles. Our preliminary data suggest that the intracavernous arteriolar component may have a significant role in the genesis of some forms of vasculogenic impotence.     

A Randomized Crossover Study Using Yohimbine and Isoxsuprine Versus Pentoxifylline in the Management of Vasculogenic Impotence

Purpose

We evaluated the efficacy and safety of yohimbine and isoxsuprine or pentoxifylline in the management of vasculogenic erectile dysfunction.

Materials and Methods

A total of 20 patients diagnosed with arterial insufficiency and cavernous venous leakage by pharmacological penile duplex scanning underwent nonhormonal oral therapy. A randomized crossover study was performed using 5.4 mg. yohimbine plus 10 mg. isoxsuprine or 400 mg. pentoxifylline 3 times daily. Response to therapy was assessed by a sexual questionnaire and repeat penile duplex ultrasonography.

Results

No patient in either phase of the study in either group had a complete response to the oral regimen(s) and there was no improvement in the pre-injection or post-injection cavernous arterial peak systolic flow velocities or resistance indexes.

Conclusions

Our study suggests that these oral agents, although well tolerated, were not effective in the management of these patients with mixed vasculogenic erectile dysfunction.     

The assessment of pelvic circulation after internal iliac arterial reconstruction:—A retrospective study of the treatment for vasculogenic impotence and hip claudication

The standard surgical treatment of vasculogenic impotence or hip claudication involves repairing vascular lesions, especially in the internal iliac arteries. It is difficult, however, to make a definite diagnosis or an accurate judgement of the therapeutic effects of this treatment due to the trouble in ruling out any other disorders. During the last five years, 19 patients with impotence and associated apparent internal iliac artery stenosis or occlusion and 2 patients with hip claudication, underwent internal iliac arterial reconstruction. The patients’ ages ranged from 37 to 70 with a mean age of 63.7 and the main procedure performed in all patients was aorto-iliac to femoral bypass grafting, or abdominal aortic aneurysmectomy. A retrospective study revealed that 74 per cent of those treated regained penile erectile activity postoperatively, and that hip claudication disappeared completely in all cases. One of the patients received percutaneous transluminal angioplasty (PTA) for the treatment of vasculogenic impotence, after which his postoperative penile brachial pressure index (PBPI) improved, demonstrating a statistically significant difference compared to the preoperative value. Trans-anal Doppler measurement also proved useful in providing complication-free perioperative understanding of pelvic circulation.     

The hypoactive corpora cavernosa with degenerative erectile dysfunction: a new syndrome

Background

In a group of 22 patients with erectile dysfunction, vasculogenic, neurogenic, endocrinologic or psychogenic investigations failed to find a cause for their erectile dysfunction. The electro-cavernosograms of these patients recorded a diminished activity. We investigated the hypothesis that diminished corpus cavernosum electromyography activity was the cause of erectile dysfunction in these patients.

Methods

The study comprised the above mentioned 22 patients (study group, 43.8 ± 5.9 SD years) and 15 healthy volunteers (control group, 41.8 ± 5.1 SD years). The electro-cavernosograms were recorded in the flaccid, erectile and detumescent phases by 2 electrodes inserted into the corpus cavernosum.

Results

The electro-cavernosogram of the healthy volunteers registered in the flaccid phase regular slow waves and random action potentials. The wave variables declined significantly in the erectile phase (p < 0.01). In the study group, the slow wave variables in the flaccid phase exhibited a significant decrease (p < 0.05) compared to the healthy volunteers, and the rhythm was irregular. Erection did not occur with sildenafil administration or intracavernosal papaverine injection, and penile implant was performed. Biopsy examination showed degenerated muscle fibers, and fragmented collagen and elastic fibers with areas of fibrosis.

Conclusion

A novel concept of the cause of erectile dysfunction was presented. Corpora cavernosa showed degenerative changes on histopathologic examination and exhibited diminished electromyography activity. They did not respond to sildenafil administration or intracavernosal papaverine injection. Penile implants were the only treatment. The condition is given the name 'hypoactive corpus cavernosum'. The cause of corpus cavernosum degenerative changes needs further study.     

Antiplatelet (aspirin) therapy as a new option in the treatment of vasculogenic erectile dysfunction: a prospective randomized double-blind placebo-controlled study

Purpose

To investigate the efficiency of antiplatelet (aspirin) therapy in vasculogenic erectile dysfunction (VED) patients with a high mean platelet volume.

Methods

A total of 184 patients diagnosed with VED between the ages of 18 and 76 were randomly divided into two groups and treated for 6 weeks [group 1: 120 patients (mean age 48.3), aspirin 100 mg/day; group 2: 64 patients (mean age 47.7), placebo 100 mg/day]. The changes from baseline to end point in erectile function scores on the International Index of Erectile Function (IIEF-EF) and the number of patients who answered “yes” to questions 2 and 3 of the sexual encounter profile (SEP) were compared statistically.

Results

The mean baseline IIEF-EF scores in groups 1 and 2 were 14.1 ± 4.9 and 14.3 ± 5.2, respectively (p = 0.7966), the number of patients who answered “yes” to SEP-2 was 62 (51.6%) in group 1 and 32 (50%) in group 2 (p = 0.8366), and the number of patients who answered “yes” to SEP-3 was 38 (31.6%) in group 1 and 20 (31.2%) in group 2 (p = 0.9557). In the aspirin group, the changes from baseline to end point in the IIEF-EF, SEP-2, and SEP-3 scores were 7.2, 36.6, and 46.6%, respectively. In the placebo group, these changes were 2.0, 9.4, and 12.5%, respectively. When compared with the placebo group, aspirin-treated subjects showed a significant improvement in all three efficacy measures (p < 0.0001).

Conclusions

100 mg of aspirin administered once a day significantly improved EF in men with VED.

     

Serum Arginase II level can be a novel indicator for erectile dysfunction in patients with vasculogenic erectile dysfunction: a comparative study

Purpose

The purpose of the study was to compare serum level of Arginase II in patients with vasculogenic erectile dysfunction (ED) versus healthy controls and to assess if its level is affected by severity of ED.

Methods

This is a prospective study that compared Arginase II in 40 patients with ED versus 40 healthy controls. Patients were excluded if they had any pelvic trauma or pelvic surgery, hormonal disorders, Peyronie’s disease, smoking, drug addiction or systemic illnesses. ED was evaluated by the validated Arabic version of the abbreviated five-item form of the international index of erectile function (IIEF-5). Serum arginase II level was assayed using ELIZA. Mann–Whitney, Kruskal–Wallis and Chi-square tests and Spearman correlation were used as appropriate and confirmed by logistic regression model.

Results

22 (55%) patients had DM. 15 (37.5%), 7 (17%), 6 (15%) and 12 (30%) patients suffered from severe, moderate, mild to moderate and mild ED, respectively. The level of serum Arginase II was significantly higher in patients than controls (p?<?0.001) and confirmed by multivariate logistic regression analysis. It also correlated significantly with age (r²?=?0.22; p?<?0.001) and IIEF-5 score (r²?=?0.8; p?<?0.001). Serum Arginase II increased significantly with more severe ED (p?<?0.001). Arginase II was also significantly higher in diabetic patients (p?<?0.001).

Conclusion

Serum level of Arginase II is significantly higher in patients with vasculogenic ED compared to healthy controls. It correlates significantly with age and IIEF-5 and was significantly affected by the severity of ED.

     

Erectile Dysfunction Following Transurethral Resection of the Prostate

Purpose

We objectively measured the incidence of erectile dysfunction following transurethral resection of the prostate.

Materials and Methods

A total of 56 men completed a questionnaire detailing perceived sexual dysfunction, and underwent nocturnal penile tumescence testing for 3 nights before transurethral resection of the prostate and again at 3 months postoperatively.

Results

Complete data were available for 40 men. No significant difference was found in penile tumescence, number of erectile events and duration of events before and after surgery. Preoperative and postoperative rigidity was statistically different, with a slight improvement after transurethral resection of the prostate (p less than 0.05). A subjective decrease in quality of erection after transurethral resection of the prostate was reported in 27.5 percent of the patients. However, on further questioning, 63.6 percent of these patients equated retrograde ejaculation with decreased potency.

Conclusions

We demonstrated no decrease in objective parameters of erectile function studies following transurethral resection of the prostate. Previous estimates of impotence after transurethral prostatectomy may have been tainted by subjective patient reports equating retrograde ejaculation with erectile dysfunction.     

Penile Vascular Assessment Using Color Duplex Sonography in Men with Peyronie's Disease

Purpose

We assessed penile vasculature in men with Peyronie's disease using color duplex ultrasound.

Materials and Methods

A total of 99 consecutive men with Peyronie's disease underwent duplex ultrasound with 60 mg. intracavernous papaverine to gain an understanding of penile vasculature and its correlation to erectile rigidity. Patients were stratified into groups according to duplex ultrasound vascular parameters and the presence or absence of impotence (that is rigidity adequate for intromission).

Results

Of 97 men 31 (32 percent) complained of impotence, 8 of 99 (8 percent) had evidence of corporeal veno-occlusive dysfunction on duplex ultrasound (defined as end diastolic flow velocity greater than 4.5 cm. per second) and 43 percent had a history of vascular risk factors that may have contributed to erectile insufficiency. Impotent patients had decreased peak systolic flow velocity, increased end diastolic flow velocity and a higher percent of vascular risk factors (p = 0.0006, 0.027 and 0.0004, respectively) compared to potent patients.

Conclusions

Duplex ultrasound provides a dynamic noninvasive functional assessment of penile vasculature in Peyronie's disease. Although corporeal veno-occlusive dysfunction has been considered the primary vascular etiology of erectile dysfunction associated with Peyronie's disease, arterial insufficiency is a major contributor, which is best detected before definitive therapy.     

The assessment of pelvic circulation after internal iliac arterial reconstruction: a retrospective study of the treatment for vasculogenic impotence and hip claudication

The standard surgical treatment of vasculogenic impotence or hip claudication involves repairing vascular lesions, especially in the internal iliac arteries. It is difficult, however, to make a definite diagnosis or an accurate judgement of the therapeutic effects of this treatment due to the trouble in ruling out any other disorders. During the last five years, 19 patients with impotence and associated apparent internal iliac artery stenosis or occlusion and 2 patients with hip claudication, underwent internal iliac arterial reconstruction. The patients' ages ranged from 37 to 70 with a mean age of 63.7 and the main procedure performed in all patients was aorto-iliac to femoral bypass grafting, or abdominal aortic aneurysmectomy. A retrospective study revealed that 74 per cent of those treated regained penile erectile activity postoperatively, and that hip claudication disappeared completely in all cases. One of the patients received percutaneous transluminal angioplasty (PTA) for the treatment of vasculogenic impotence, after which his postoperative penile brachial pressure index (PBPI) improved, demonstrating a statistically significant difference compared to the preoperative value. Trans-anal Doppler measurement also proved useful in providing complication-free perioperative understanding of pelvic circulation.     

Import Catheter in Erectile Dysfunction

Purpose

We propose an alternative technique for intracavernous self-injection of sodium nitroprusside for erectile dysfunction by inserting a Medtronic ImPort^* catheter with a valved tip.

Materials and Methods

A silicone catheter was implanted in 3 patients with psychogenic impotence. The reservoir, which is used for vasoactive agent injection, was implanted laterally to the anterosuperior iliac spine and the distal tip of the catheter was inserted into the corpora cavernosa via a subcutaneous tunnel. The injection technique was taught to the patient and the initial injection was performed 1 week later.

Results

All patients and partners were satisfied with the technique and quality of erections at a mean followup of 14 months. There were no major local complications due to catheter implantation and no systemic complications due to sodium nitroprusside injection.

Conclusions

An alternative technique for intracavernous pharmacotherapy of inserting an ImPort catheter prevented the complications of intracavernous injections in patients with erectile dysfunction.     

Residual renal function and erectile dysfunction in patients on hemodialysis

Introduction

Residual renal function and erectile dysfunction are important parameters of quality of life in dialysis patients.

Goal

The purpose of our investigation was to determine correlations between erectile dysfunction and residual diuresis in patients on hemodialysis.

Methods

The survey was organized as a cross-sectional study in men aged up to 65?years on hemodialysis. All respondents voluntarily completed the questionnaire of the International Index of Erectile Function (IIEF)-5. Demographic and anthropometric characteristics, the duration of dialysis, smoking, alcohol consumption, residual renal function, comorbidity, and routine biochemical parameters were determined for all patients. The adequacy of dialysis was calculated as Kt/V. Based on residual renal function, the patients were divided into a group without residual diuresis and a group with preserved residual renal function.

Results

Nearly two-thirds of our patients did not have preserved diuresis, while 82.8% of our respondents had erectile dysfunction. Patients with preserved residual renal function were heavier (P?=?0.047) and had higher body mass index (P?=?0.047), but the prevalence of cardiovascular disease (P?<?0.0001) and erectile dysfunction (P?<?0.0015) was lower, compared to patients without residual diuresis. The regression model also demonstrated a statistically significant relationship between the residual diuresis and the total IIEF score (b?=?4.74; P?<?0.001).

Conclusion

Hemodialysis patients with preserved diuresis retain erectile function better.     

Impotence and Incontinence After Immediate Realignment of Posterior Urethral Trauma: Result of Injury or Management?

Purpose

We examined further whether the injury or method of management is responsible for impotence and incontinence after immediate realignment of prostato-membranous urethral disruptions.

Materials and Methods

A total of 20 patients with complete urethral disruptions treated with immediate realignment (group 1) was compared to 12 with partial or complete injuries treated with retrograde catheterization alone (group 2). Followup status was obtained by patient questionnaire or telephone interview.

Results

Of the patients 83 percent in group 1 and 80 percent in group 2 are continent, and 76 percent and 70 percent, respectively, regained erections suitable for sexual intercourse.

Conclusions

The results suggest that impotence and incontinence in this setting are the result of the injury and not of attempts at immediate surgical management.     

THE EFFECT OF THE SPECIFIC PHOSPHODIESTERASE (PDE) INHIBITORS ON HUMAN AND RABBIT CAVERNOUS TISSUE IN VITRO AND IN VIVO

Purpose

Phosphodiesterases (PDE) are key enzymes in the regulation of the smooth muscle tone. Experimental studies showed PDE III and V-isoenzymes to play an important role in the smooth muscle tone regulation of corpus cavernosum. Recently, a specific PDE III-inhibitor (milrinone) and a PDE V-inhibitor (sildenafil) were introduced in clinical studies. An experimental study was done to examine a potential role of PDE-inhibitors in the treatment of erectile dysfunction.

Materials and Methods

In the organ bath, strips from human and rabbit corpus cavernosum were precontracted and increasing doses of PDE inhibitors were added. In patients with erectile dysfunction as well as in rabbits, intracavernous injections of milrinone were done.

Results

PDE-inhibitors dose-dependently relaxed human and rabbit corpus cavernosum strips. In the precontracted human cavernous tissue, milrinone and sildenafil were equally potent and efficacious in vitro. In the rabbit, milrinone induced slight tumescence but dramatic circulatory side effects. In patients, penile tumescences as well as full erections were observed.

Conclusions

Milrinone strongly relaxes human cavernous smooth muscle cells but it exhibits low relaxant effects in the rabbit cavernous tissue. In human tissue, sildenafil was equieffective with milrinone in vitro. In vivo, milrinone induced a good erectile response in humans but a poor erectile effect in rabbits. Our results support a possible potential for selective PDE-III and -V inhibitors in the treatment of impotence and give further evidence that the rabbit is an animal model of limited value to study the effects of drugs on cavernous smooth muscle tone regulation in vivo.     

Embolisation of high flow extracranial/peripheral arteriovenous malformations (AVMs) with ethylene vinyl alcohol copolymer (ONYX®) in children—Birmingham Children’s Hospital experience

Background

ONYX® is a non-adhesive liquid embolic agent, ethylene vinyl alcohol copolymer dissolved in various concentration of dimethyl sulfoxide. Onyx has been used for endovascular treatment of cerebral vascular malformation. In our series, we present our experience in seven paediatric patients with peripheral high-flow arteriovenous malformations (AVMs) treated with Onyx.

Methods

Seven patients were treated in our institution from 2005 to 2010 for their AV malformation with Onyx embolisation. Their case notes were reviewed and data on site, stage, number of embolisations, pre and post-procedure stage of AVMs and complications noted.

Results

AVMs involving profunda femoris, posterior tibial arteries, facial and maxillary arteries were embolised with Onyx. Three patients received multiple embolisation procedures. All AVMs were downgraded from Schobinger III to Schobinger I after embolisation. Two patients underwent surgical removal of AVM post-embolisation. One patient experienced post-procedure pain, skin ulceration and necrosis, which was managed conservatively. One patient had stiffness and discomfort over ankle joint. Onyx induced an inflammatory reaction in tissues in one patient.

Conclusions

In our experience, Onyx embolisation of extracranial high-flow AVM in children has shown to downgrade the stage of AVMs which are otherwise very difficult condition to treat surgically. Appropriate use of Onyx decreases complications and achieves symptomatic improvement. Level of Evidence: Level V, therapeutic study.     

Erectile dysfunction and atrial fibrillation: A systematic review and meta‐analysis

Objective

To investigate the pooled incidence or the prevalence of erectile dysfunction, and to assess the risk of erectile dysfunction in patients with atrial fibrillation.

Methods

A systematic review was carried out in the MEDLINE, EMBASE and Cochrane databases from inception through January 2018 to identify: (i) studies that reported the incidence and/or prevalence of erectile dysfunction in atrial fibrillation patients; or (ii) studies that assessed the association between atrial fibrillation and erectile dysfunction. Pooled odds ratios and 95% confidence intervals were calculated using a random effects model.

Results

Five observational studies (27 841 patients) were enrolled. The pooled estimated prevalence of erectile dysfunction in atrial fibrillation patients was 57% (95% confidence interval 50–64, I² = 0). A study showed an incidence of newly diagnosed erectile dysfunction in atrial fibrillation patients of 0.96% during the mean follow‐up duration of 4.67 ± 3.20 years. There was a significant association of atrial fibrillation with an increased risk of erectile dysfunction, with a pooled odds ratio of 1.79 (95% confidence interval 1.44–2.23, I² = 0%). The data on the risk of atrial fibrillation development in patients with erectile dysfunction were limited. A study showed the comparable risk of atrial fibrillation in patients with erectile dysfunction (odds ratio 1.03, 95% confidence interval 0.67–1.5), when compared with those without erectile dysfunction.

Conclusions

The present study suggests a significant association between erectile dysfunction and atrial fibrillation. The overall estimated prevalence of erectile dysfunction among atrial fibrillation patients is 57%. However, despite limited data, the current evidence suggests a low incidence of new erectile dysfunction in atrial fibrillation patients.

     

Neurovascular bundle size measured on 3.0-T magnetic resonance imaging is associated with the recovery of erectile function after robot-assisted radical prostatectomy

Background and objective

Erectile dysfunction is one of the complications occurring after radical prostatectomy (RP), and recovery of erectile function is quantitatively related to the preservation of the neurovascular bundles (NVB).We evaluated the significance of NVB area on functional outcomes after RP.

Is the plasma endocan level a reliable predictor for the severity of erectile dysfunction?

Purpose

The aim of our study was to assess the correlation between serum endocan level and erectile dysfunction (ED).

Methods

A total of 92 patients were reviewed in this study after institutional review board approval. The patients’ characteristics were recorded, including age, body mass index, blood pressure, smoking history, serum creatinine, glucose, lipid profile, total testosterone, and Beck Depression Inventory scores. ED was evaluated with the Sexual Health Inventory for Men (SHIM) questionnaire and classified as severe, moderate, or mild. Scores of >?18 indicate normal erectile function and were recruited for the control group.

Results

Sixty-three patients with a median age of 56 years in the ED group and 29 patients with a median age of 55 years in the control group were compared. ED was classified as severe in 20, moderate in 25, and mild in 18 patients. A significant difference was determined between the severe ED group and the control group for serum endocan levels (p?<?0.001). A significant negative correlation between the SHIM score and endocan levels (rho ? 0.65; p?<?0.01), age and SHIM score (rho ? 0.32; p?=?0.04), BMI and SHIM score (rho ? 0.25; p?=?0.03), and BMI and total testosterone (rho ? 0.16; p?=?0.04) was determined upon Spearman’s correlation analysis. A positive correlation was also determined between total testosterone and SHIM score (rho 0.50; p?=?0.04). Patients’ age (p?=?0.037) and serum endocan level (p?=?0.029) were determined as significant in the multivariate analysis.

Conclusion

This study demonstrated the presence of an association between plasma endocan levels and ED. Endocan may be used as a new diagnostic marker for the severity of ED.

     

Management of Erectile Dysfunction and Infertility in the Male Spinal Cord Injury Patient

Purpose of Review

Men with spinal cord injury (SCI) commonly suffer from erectile dysfunction and ejaculatory dysfunction. The literature regarding the causes and treatment of these two important problems was reviewed.

Recent Findings

Many of the erectile dysfunction treatments applied to able bodied individuals are also useful in the SCI population, although there are differences in the goals and results of treatment. Ejaculatory dysfunction can be treated with either penile vibratory stimulation or electroejaculation with high success rates. Pregnancies are possible, but poor quality sperm quality in male SCI patients leads to pregnancy rates lower than is observed in the able-bodied population.

Summary

Although effective treatments are available for erectile and ejaculatory dysfunction in men with SCIs, many challenges remain in optimizing the treatment of these individuals.

     

Nervenerhaltende radikale Prostatektomie mit niedrig dosiertem Sildenafil

Objective

The purpose of this study was to evaluate the effect of low-dose sildenafil (25 mg) for rehabilitation of erectile function after nerve-sparing radical prostatectomy.

Patients and methods

In a prospective study, 43 sexually active patients underwent nerve-sparing retropubic radical prostatectomy. Rigiscan® measurement of nocturnal penile tumescence and rigidity (NPTR) was carried out 7–14 days after surgery. A group of 23 patients with preserved nocturnal erections received sildenafil 25 mg/day at night to support recovery of erectile function. A control group of 18 patients underwent follow-up without PDE-5 inhibitors. Evaluation using the IIEF-5 questionnaire was performed 6, 12, 24, 36, 52 and 78 weeks after the operation.

Results

Of 43 patients, 41 (95%) showed 1–5 erections during the first night after catheter removal. In the group receiving daily sildenafil, the mean IIEF-5 score decreased or increased from 20.8 preoperatively to 3.6 at 6 weeks, 3.8 at 12 weeks, 5.9 at 24 weeks, 9.6 at 36 weeks, 14.1 at 52 weeks and 19.3 at 78 weeks after prostatectomy. In the control group, the mean preoperative IIEF-5 score of 21.2 decreased or increased to 2.4 at 6 weeks, 3.8 at 12 weeks, 5.3 at 24 weeks, 6.4 at 36 weeks, 9.3 at 52 weeks and 13.2 at 78 weeks. Statistical evaluation showed significant differences regarding the IIEF-5 score and recovery period of erectile function between the groups (p<0.001), with potency rates of 92 vs 68%.

Conclusion

The measurement of NPTR after nerve-sparing radical prostatectomy showed erectile function as early as the first night after catheter removal. In cases of early penile erections, daily low-dose PDE-5 inhibitors lead to a significant improvement/acceleration of erectile function recovery.