Penile trauma: an etiologic factor in Peyronie's disease and erectile dysfunction

Implications of nitric oxide synthase isoforms in the pathophysiology of Peyronie's disease

Peyronie's disease is an idiopathic, localized connective tissue disorder of the penis which involves the tunica albuginea of the corpus cavernosum and the adjacent areolar space. Peyronie's disease is characterized by local changes in the collagen and elastic fiber composition of the tunica albuginea. The formation of fibrotic plaques alters penile anatomy and can cause different degrees of bending and narrowing, as well as penile pain and erectile dysfunction. Though long recognized as an important clinical entity of the male genitalia, the etiology of this disease has remained poorly understood. Until recently there have been no studies to examine the role nitric oxide (NO) and nitric oxide synthase (NOS) isoforms may play in the onset and progression of Peyronie's disease. NO is a potent biological mediator with diverse physiological and pathophysiological roles. The purpose of this review is to describe each of the NOS isoforms and their potential roles in the pathophysiology of Peyronie's disease, with particular emphasis on the regulation of endothelial and inducible NOS isoforms.

Gene expression in Peyronie's disease

Currently, surgical intervention is the only efficacious treatment for Peyronie's disease (PD), a fibromatosis of the tunica albuginea of the penis. Therapies based on the molecular pathways for this disease could provide alternatives to surgical treatment but only recently has the pathophysiology of the Peyronie's disease plaque been investigated at the molecular level. In this review, we examine the current knowledge of gene expression in the PD plaque and the relationship of PD with other fibrotic conditions such as Dupytren's disease. TGFbeta1, along with other growth factors, pro-fibrotic genes, and collagen, are expressed in fibroblasts and myofibroblasts. Myofibroblasts are normally involved in wound contracture and largely eliminated via apoptosis during the late stages of wound remodeling. In the PD plaque, however, these cells persist and may play an important role in the PD plaque fibrosis. The expression levels of TGFbeta1 and pro- and anti-fibrotic gene products, along with the nitric oxide/reactive oxygen species (NO/ROS) ratio in the tunica albuginea, appear to be essential for the formation and progression of the PD plaque and effect the expression of multiple genes. This can be assessed with the recently developed DNA-based chip arrays and results with the PD plaque have been encouraging. OSF-1 (osteoblast recruitment), MCP-1 (macrophage recruitment), procollagenase IV (collagenase degradation), and other fibrotic genes have been identified as being possible candidate regulatory genes. Finally, possible therapeutic avenues for gene-based therapy in the treatment of PD are discussed that may eventually reduce the need for surgical intervention.

Intralesional interferon-alpha-2b for the treatment of Peyronie's disease

Peyronie's disease can best be described as a localized connective tissue disorder that primarily affects the tunica albuginea of the penis. The disease may be attributed to repetitive vascular trauma that initiates an inflammatory process and ultimately leads to the formation of a fibrous penile plaque. The plaque consists mainly of collagen and can significantly alter penile anatomy and function. Patients with Peyronie's disease will most often present with penile curvature, pain on erection, a palpable nodule most commonly located on the dorsal shaft of the penis, and erectile dysfunction. There is no definitive treatment for Peyronie's disease and the treating physician has many options. They may wait for spontaneous resolution of the plaque, choose medical therapy (which includes both oral and intralesional regimens), or opt for surgical management. The main purpose of this article is to discuss the advances in medical therapy for Peyronie's disease, in particular intralesional injection of interferon-alpha-2b (IFN-alpha-2b). Several studies have concluded that IFN-alpha-2b can be an effective modality of treatment and that many patients placed on a regimen of IFN-alpha-2b experienced a significant reduction in penile curvature, diminished pain with erection, and decreased size of the plaque. Further clinical studies are currently being undertaken to determine the precise quantity and frequency of administration of IFN-alpha-2b that is most effective with the least amount of side effects.

Pathophysiology of Peyronie's disease

Peyronie's disease is an inflammatory condition characterized by the formation of fibrous, noncompliant nodules in the tunica albuginea which can impede tunical expansion during penile erection, leading to deformity and bending. While the cause of this disease is thought to be due to microvascular trauma and abnormal wound healing, other hypotheses include genetic predisposition. In this review the pathophysiology of Peyronie's disease is discussed as well as current hypotheses regarding its origin.

Epidemiology of Peyronie's disease

Francois Gigot de la Peyronie, surgeon to Louis XV of France, has become synonymous with the rather enigmatic though not uncommon condition of Peyronie's disease (PD), a localized connective tissue disorder of the penile tunica albuginea. The true prevalence of Peyronie's disease is unknown. Therefore, we decided to perform an evaluation of existing epidemiological data. A prevalence rate of 3.2% was determined in male inhabitants of the greater Cologne area. This is much higher than revealed by the data reported up to now, thus rendering the accepted prevalence rates of 0.3% to 1% untenable. The actual prevalence of Peyronie's disease may be even higher, considering many patients' reluctance to report this embarrassing condition to their physicians. Along these lines, most clinicians note that the number of Peyronie's patients has increased since the advent of oral sildenafil. Comparably high prevalences are known for diabetes and urolithiasis, suggesting a greater frequency of this rare disease than formerly believed.

A retrospective review of 307 men with Peyronie's disease

PURPOSE

We discuss the clinical appearance and natural outcome of Peyronie's disease.

MATERIALS AND METHODS

During an 8-year period 307 men with Peyronie's disease were evaluated, and clinical characteristics, risk (factors), penile deformities, erectile status and outcome were analyzed.

RESULTS

Mean patient age plus or minus standard deviation was 52.8 +/- 9.3 years (range 23 to 76). Penile deformity, pain on erection and palpable nodule were the most common (85%) presenting symptoms, usually in different combinations. The remaining 15% of men (mean age 59.4 +/- 6.5 years) were not aware of the penile deformity and were diagnosed during standard evaluation for erectile dysfunction. Dorsal (45.6%) and lateral (29.3%) were the most common curvatures. The degree of deformity was less than 30 degrees in 42.7% of patients, 31 to 60 degrees in 38.8% and greater than 60 degrees in 18.6%. At least 1 risk factor for systemic vascular disease was identified in 67.5% of patients, and hypercholesterolemia and diabetes were the most common. Patients with at least 1 risk factor had a significantly higher risk for severe penile deformity. Of the men 54.4% complained of erectile dysfunction and the probability of diminished erectile capacity was 86.7% in patients older than 60 years, with Peyronie's disease for more than 12 months and at least 1 risk factor. Of 63 patients presenting with the acute phase of disease penile deformity deteriorated in 30.2%, did not change in 66.7% and resolved spontaneously in 3.2% without any treatment after a mean followup of 8.4 months.

CONCLUSIONS

Our data show that penile deformities are disabling (greater than 30 degrees) in 62.5% of cases. Risk factors, such as serum lipid abnormalities, diabetes and hypertension, seem to have significant impact on the severity of symptoms and outcome. Patients must be informed that Peyronie's disease is progressive in 30.2% without treatment and spontaneous resolution is rare.

The prevalence of Peyronie's disease: results of a large survey

OBJECTIVES

To determine the prevalence of Peyronie's disease, a localized connective tissue disorder of the penile tunica albuginea, the symptoms of which include palpable plaque, painful erections and curvature of the penis, in a large sample of men in Germany.

SUBJECTS AND METHODS

A standardized questionnaire was sent to 8000 male inhabitants (age range 30-80 years) of the greater Cologne area (approximately 1.5 million inhabitants). Three questions about the self-diagnosis of Peyronie's disease were previously assessed for validity on 158 healthy men and 24 patients with confirmed Peyronie's disease. To optimize the response rate, the questionnaire was mailed three times to all the men.

RESULTS

The response rate after the third mailing was 55.4% (4432 men): 142 men (3.2%, mean age 57.4 years, SD 13.4) reported the new appearance of a palpable plaque which, from the previous validation, was the most sensitive question and the main symptom of the disease. In men aged 30-39 years only 1.5% reported localized penile induration, compared with 3.0% in those 40-49 and 50-59 years, 4.0% in those 60-69 years and 6.5% of those > 70 years old. Newly occurring angulation was reported by 119 of the 142 men (84%) and painful erection by 66 (46.5%). The combination of the three symptoms (plaque, deviation and painful erection) was reported by 46 of the 4432 respondents (1.04%), i.e. 32% of the 142 men with penile induration; 58 of the 142 men (41%) reported erectile dysfunction.

CONCLUSIONS

This is the first large cross-sectional, community-based study to examine the prevalence of Peyronie's disease. Using previously validated questions the prevalence of Peyronie's disease in the sample was 3.2%; this is much higher than indicated in previous reports. A comparably high prevalence is reported for diabetes and urolithiasis, suggesting that this 'rare' disease is more widespread than previously thought.

New advances in Peyronie's disease

The formation of Peyronie's disease plaques is a process that seems to involve a cascade of genetic, structural and immunologic events. Clinical manifestations include penile deformity and possible erectile dysfunction. Rational strategies have been forthcoming, with both minimally invasive and surgical treatments of Peyronie's disease available. This article reviews and updates current scientific and clinical advances in Peyronie's disease.

Genitourinary trauma

Injuries to the GU system commonly occur in patients with high-energy lower abdominal or pelvic trauma. The emergency physician should be well versed in the diagnosis and management of GU trauma, although these injuries are not usually life threatening because of the potential for loss of urinary or sexual function. In the setting of hemodynamic instability, diagnosis and treatment of GU injuries is often accomplished in the operative setting. In the stable patient, diagnostic testing is directed by the type of suspected injury and must proceed in a reverse manner, i.e., external injury then urethral injury then bladder, and finally urethral and renal damage. Treatment focuses on a team approach between the emergency physician, general, orthopedic, and urologic surgeon. The decision for operative repair is often dictated more by other associated injuries than urologic injuries, and the urologic surgeon often provides temporizing measures with definitive repair at a later time. Prompt diagnosis and treatment of injuries to the external genitals results in excellent long-term outcome, minimizing the devastating consequences of impotence, urinary incontinence, and sexual disfiguration.

Peyronie's disease

Peyronie's disease remains one of the most perplexing diseases in urology. With continued basic research in wound healing and scarring, the understanding and management of this frustrating disease will improve. Initial treatment of Peyronie's disease should be conservative, with expectant therapy and medical management. Once the penile curvature and plaque have stabilized, patients with severe deformity can be offered surgery depending on their symptoms and complaints. Patient selection is the key to proper treatment. Less experienced surgeons should limit themselves to medical management or simple surgical management of the disease, including plication or Nesbit procedures. Penile-lengthening procedures or the placement of complicated penile prosthesis should be reserved for surgeons with familiarity and expertise in this type of reconstruction. Education on the pathogenesis and natural history of the disease will allow the patient and his partner to make an informed decision in regards to treatment options and expected outcomes.

Peyronie's disease: advances in basic science and pathophysiology

Peyronie's disease is an idiopathic, localized connective tissue disorder of the penis that involves the tunica albuginea of the corpus cavernosum and the adjacent areolar space. The tunica albuginea plays an important role in the mechanism of erection. Peyronie's disease is characterized by local changes in the collagen and elastic fiber composition of the tunica albuginea. The formation of fibrotic plaques alters penile anatomy and can cause different degrees of bending, narrowing, or shortening of the penis. Moreover, a significant number of men with Peyronie's disease develop erectile dysfunction. Penile blood flow studies in many patients with Peyronie's disease suggest a strong association with veno-occlusive dysfunction. Although long recognized as an important clinical entity of the male genitalia, the etiology of this disease has remained poorly understood. The following review focuses on recent research on the pathophysiology of Peyronie's disease.

Low-dose radiotherapy in 179 patients with Peyronie's disease: treatment outcome and current sexual functioning

PURPOSE

To analyse retrospectively treatment outcome in patients irradiated for Peyronie's disease.

METHODS AND MATERIALS

The records of 179 patients, median age 52 years, that received radiotherapy (RT) between 1982 and 1997 were reviewed. 78% presented with painful erections and 89% with penile deformity. The symptoms were present for a median duration of 6 months (range, 1-72 months). The RT schedule consisted of 13.5 Gy (9 x 1.5 Gy, 3 fractions per week) using orthovoltage X-rays in 123 patients or 12 Gy (6 x 2 Gy, daily fractions) using electrons in 56 patients. A questionnaire regarding current sexual functioning was mailed to 130 patients whose addresses could be traced; 106 (82%) responded.

RESULTS

At mean follow-up period of 3 months, 83% reported that pain was diminished or had disappeared after RT. Twenty-three percent of patients reported a decrease in penile deformity. Following RT, surgical correction of penile curvature was performed in 29% of patients. No RT-related complications occurred except transient dysuria in 1 patient. Questionnaire data: 72% of patients were currently sexually active, 48% had erectile dysfunction, and 49% expressed dissatisfaction with their current sexual functioning.

CONCLUSION

Low-dose external RT (12-13.5 Gy) results in relief of pain in the majority of patients with Peyronie's disease. Improvement in penile deformity was observed, avoiding surgery in a number of patients. No significant RT-associated morbidity was encountered. It is disappointing that almost 50% of patients complain of sexual functioning, but this is presumably not related to radiotherapy.

New aspects in Peyronie's disease--a mini-review

There have been several advances in elucidation of the pathogenesis of Peyronie's disease. Transforming growth factor beta 1 seems to play a major role in this disease, while the importance of penile trauma is a matter of debate. High-resolution ultrasound sonography is the method of choice in detecting penile plaques, while magnetic resonance imaging is useful in the evaluation of actively inflamed plaques. There are still differences of opinion on the best drug therapy in noncalcified plaques. The results on tamoxifen or interferon therapy vary between useless and useful. Potassium-para-aminobenzoate seems to have a significant effect in decreasing plaque size and deviation angle. The operative strategy for big plaques or complex deviation has changed to the 'small incision' graft, leading to far lower post-operative impotence rates. Iontophoresis seems to be worthy of further trials, while the results of extracorporal shock wave therapy have to be discussed critically.

Penile fibrotic changes after radical retropubic prostatectomy

OBJECTIVE

To investigate the type of penile deformity, response to treatment of and predictive factors for the formation of penile fibrotic changes after radical retropubic prostatectomy (RRP).

PATIENTS AND METHODS

Between July 1996 and September 1998, 110 men who had undergone RRP a mean (SD, range) of 35 (20, 5-145) months previously were evaluated by one physician for their erectile dysfunction. Those men affected by penile fibrotic changes were advised to initiate medical therapy for possible Peyronie's disease; their charts were reviewed and they were interviewed to determine the outcome.

RESULTS

Overall, 45 of 110 patients (41%) with erectile dysfunction after RRP had penile fibrotic changes, representing 11% of all patients undergoing RRP in the specified period. The primary clinical presentation included penile curvature in 42 men (93%) and 'waistband' deformity in 11 (24%; some had both); palpable plaques were present in 31 (69%). On assessing the outcome in 40 men, 16 (40%) felt that their condition had improved, half were unchanged and 10% progressed, within a mean follow-up of 24 months after diagnosis. Of the 16 improved, 14 were regularly using a vacuum constriction device or injection therapy. No significant factors predictive of the fibrotic changes could be identified, including the use of intracavernosal injection therapy before onset, neurovascular bundle resection, operative duration, estimated blood loss and pathological tumour grade or stage.

CONCLUSIONS

Penile fibrotic changes are a significant but previously undescribed problem in men after RRP. Although predisposing factors could not be identified, most men felt that their condition stabilized or improved during treatment. Corroborative confirmation of this association and its aetiology will require prospective studies.

Tamoxifen versus placebo in the treatment of Peyronie's disease

PURPOSE

We evaluated the effects of oral tamoxifen and placebo in patients with Peyronie's disease.

MATERIALS AND METHODS

We selected 25 patients with Peyronie's disease who did not have calcified plaque for treatment in the andrology outpatient clinic. A medical history was obtained, and physical examination, penile x-ray, penile ultrasound and pharmacologically induced erection with prostaglandin E1 were performed. Patients were randomly divided into group 1--those who received 20 mg. tamoxifen twice daily for 3 months and group 2--those who received placebo for the same period. The same evaluations were done 4 months later and results were compared. Qualitative (chi-square test) and quantitative (Student's t test) results were analyzed using the Yates correction factor with p <0.05 considered significant.

RESULTS

Pain subsided in 66.6 and 75% of the patients treated with tamoxifen and placebo, respectively (p >0.05). In groups 1 and 2 a reduction in the penile deformity was noticed by 46.1 and 41.7% of the patients (p >0.05), and a decrease in plaque size was noticed by 30.7 and 25%, respectively. On the other hand, objective measurements did not reveal any difference in plaque area or curvature angle.

CONCLUSIONS

This study did not show significant improvement in pain, curvature or plaque size in patients with Peyronie's disease who were treated with tamoxifen compared with those treated with placebo.

Treatment of Peyronie's disease by extracorporeal shockwave therapy: evaluation of our preliminary results

BACKGROUND

Peyronie's disease is an idiopathic disorder of the penis that produces erectile dysfunction. It affects mainly the tunica albuginea. We describe our preliminary results with extracorporal shockwave therapy (ESWT) as a new noninvasive modality for the treatment of Peyronie's disease.

PATIENTS AND METHODS

In this study, 24 patients aged 36 to 67 years were treated with ESWT on the Lithostar overhead-module (Siemens). All our patients had unsuccessful medical treatment before ESWT. The average plaque was 7x15 mm. The number of shockwaves ranged from 15,000 to 25,000 (18-21 kV) delivered in four to ten sessions. Most patients needed local anesthesia before therapy.

RESULTS

Four patients (17%) showed marked improvement and complete remission of the penile deviation. Six patients (25%) showed partial remission with painless erections after treatment. Four patients had painless erections after treatment but still had some penile deviation. In 10 patients (41%), ESWT failed, necessitating subsequent penile surgery.

CONCLUSIONS

Our preliminary results with a response rate of 59% with ESWT for Peyronie's disease, including a 17% complete remission rate, is encouraging. However, further multicenter studies will have to prove if ESWT is a real therapeutic option for this disease.

A case-control study on risk factors for Peyronie's disease

The aim of this study was to investigate the relationship between history of selected diseases, genital traumas, and Peyronie's disease. A hospital-based case-control study was conducted at the Andrologic and Surgical Outpatient Units of the Policlinico Gemelli, Rome, where 134 men with Peyronie's disease and 134 male controls were interviewed. The association between Peyronie's disease and selected characteristics was estimated by means of odds ratios (OR) and 95% confidence intervals (CI). Patients who underwent invasive procedures on the penis (i.e., urethral catheterization, cystoscopy, and transurethral prostatectomy) had a 16-fold increased risk for Peyronie's disease (OR = 16.1, 95% CI: 1.8-142), while a nearly three-fold increase was observed among patients who had genital and/or perineal traumatisms (95% CI: 1.0-7.1). A history of urethritis, uricacidemia, and lipoma was also significantly associated with an increased risk for Peyronie's disease. Twenty-one percent of the cases and none of the controls were affected by Dupuytren's contracture, and 4% of cases and none of the controls reported familial history for Peyronie's disease. The frequency of inflammatory or fibromatous lesions of the genital tract of the partner was significantly higher in men with Peyronie's disease than among controls. These results were consistent when performing a stratified analysis according to the type of controls (i.e., controls affected by urologic or by digestive conditions) to rule out the potential effect of recall bias. The findings of the study lend support to clinical reports stressing the importance of genital traumatisms and genetic conditions in the development of Peyronie's disease.

Peyronie’s disease

The pathogenesis of Peyronie's disease is still not well understood. As a result, the treatment of Peyronie's disease remains a dilemma and new therapies continue to evolve. This article discusses present understanding, controversy and new discoveries related to this condition.