A discrepancy of penile hemodynamics during visual sexual stimulation observed by near-infrared spectroscopy

Background

In this paper, we observed a discrepancy of penile hemodynamics dependent on location by using near infrared spectroscopy (NIRS) sensor, and showcase NIRS as a potentially suitable sensor in supplementing the diagnosis and treatment of erectile dysfunction.

Methods

To observe the effect that location has on penile hemodynamics, the NIRS sensor was placed on the top and the side of genital organ, and oxy- (HbO), deoxy-(RHb), and total (HbT) hemoglobin concentration changes were acquired. Our results from 6 healthy subjects show that hemodynamic changes vary depending on where the probe was placed. To observe a statistical difference between the signals, a Wilcoxon signed-rank test was performed.

Results

The result shows a significant difference (p < 0.05) between concentration changes of RHb and HbT depending on the probes’ location. Moreover, the sensor placed on the top of the organ shows a rise of HbO and HbT concentration while RHb concentration decreased. However, hemodynamics from the side of the organ showed that RHb concentration increased along with HbO.

Conclusions

The outcomes demonstrates an ability of NIRS to be sensitive enough to detect the different hemodynamic changes in various locations of a healthy male genital organ during visual sexual stimulation. The results also show the importance of sensor location on the genital organ for the resulting hemodynamic changes. We can foresee our results as a way for clinicians to obtain more accurate hemodynamic measurements from the penis, and also show the likelihood for NIRS enhanced diagnosis tool of male erectile dysfunction over the current standards.     

Feline penile erection induced by transurethral administration of sodium nitroprusside

Nitric oxide (NO) is an important mediator in the relaxation of cavernosal smooth muscle. The aim of this study was to investigate the in vivo feline erectile response after transurethral administration of sodium nitroprusside (SNP), a NO donor drug. Erectile responses after administration of transurethral SNP were compared with those elicited by an intracavernosal control triple-drug combination (1.65 mg papaverine, 25 μg phentolamine, and 0.5 μg prostaglandin E₁). SNP was administered via a 20-gauge Jelco intravenous catheter in a volume of 200 μl and changes in intracavernosal pressure, penile length, and systemic blood pressure were monitored. The control triple-drug combination was administered via a 30-gauge needle at the end of each experiment to serve as a control reference. Transurethral administration of SNP (1–4 mg) induced penile erection in a dose-dependent manner with minimal changes in systemic blood pressure. The maximum increase in intracavernosal pressure and penile length after transurethral administration of SNP (4 mg) was significantly less than after the intracavernosal injection of the control triple-drug combination (P < 0.01). These data suggest that transurethral administration of SNP can induce an erectile response in cats with minimal side effects. Received: 17 December 1998 / Accepted: 14 April 1999     

Spontaneous and prolonged drug-induced erection in a patient with inflatable penile implant

Achievement of spontaneous tumescence after penile implant surgery has already been reported. However, regular spontaneous full, rigid erection upon sexual arousal that is adequate for vaginal penetration and tumescence for satisfactory sexual performance is an extremely rare condition in men with three-piece hydraulic implants. Similarly, prolonged erection is not expected in such implant cases even with the use of erectogenic agents. We report this interesting phenomenon confirmed by magnetic resonance imaging technique in a patient with inflatable device.     

Is deep dorsal vein arterialization effective in elderly patients?

Objective Arterialization operations of the penis are recommended for young patients with erectile dysfunction (ED). In this study, we investigated the efficiency of deep dorsal vein arterialization (DDVA) in carefully selected healthy elderly patients Patients and methods An initial extensive evaluation with corpus cavernosum electromyography, cavernosometry, and penile doppler ultrasonography was performed for 43 elderly patients with ED for whom the presence of risk factors (hypertension, diabetes, hyperlipidemia, smoking habit, psychiatric or neurologic disorders, liver or kidney failure, and history of major trauma) had been ruled out. All patients underwent to DDVA using the Furlow–Fisher technique. Surgical outcome was tested postoperatively by use of the fifteen-item International Index of Erectile Function questionnaire (IIEF-15). Surgical success was assumed if the score in the five-item version of the IIEF (IIEF-5) had increased by at least five points. Results Of the patients, 21 were detected to have caverno-occlusive disease, 13 had arteriogenic disease, and 9 had both caverno-occlusive and arteriogenic disease. The mean age of the patients was 59.7 ± 4.6 years and the mean follow-up time was 22.1 ± 7.1 months. The operation was successful in 26 cases (60.5%) according to IIEF-5. Total IIEF-15 score was increased from 19.2 ± 5.0 to 28.5 ± 9.4 (P < 0.05). Significant increases were observed in the erectile function, intercourse satisfaction, and overall satisfaction domains of IIEF-15. The preoperative degree of ED or the etiology of ED had no impact on the surgical results. Percent changes in the total IIEF-15 score and in its domains were no different between patients aged <60 and those aged ≥60. Conclusion DDVA could successfully be performed for carefully selected elderly patients as long as the presence of risk factors for ED are ruled out.     

Neurophysiology of penile erection

Summary In 6 dogs and 6 monkeys electrical stimulation of the cavernous, pudendal and hypogastric nerve was performed to gain better understanding of the erectile neurophysiology. Arterial flow, intracorporeal pressure and venous restriction studies during single and combined neurostimulation demonstrated that initiation and maintenance of erection is a parasympathetic phenomenon. Penile rigidity however, could only be achieved with additional pudendal nerve stimulation resulting in muscular compression of the blood distended cavernous bodies. Detumescence or subsidence of erection is primarily under sympathetic control, due to inhibition of sinusoidal smooth muscle relaxation. On the basis of our observations we conclude that penile erection is dependent upon three neurophysiological mechanisms: 1. the parasympathetic vascular mechanism, the somatomotor muscular mechanism and the sympathetic inhibitory mechanism.Part of this paper was presented at the 9th Symposium of the Association for Experimental Urology of the German Urological society, June 17–18, 1988, Aachen, Federal Republic of Germany     

Prevention of erection after penile surgery

Summary To prevent noctural erections after penile surgery a randomized, double blind trial of nocturnal intracavernous infusion of noradrenaline (10 micrograms per hour) versus placebo in 20 patients was carried out. During infusion the corpus cavernosum pressure was continuously registered. The patients made a record of nocturnal erections and associated pain. The pressure registration confirmed total absence of erections in the noradrenaline group. In the placebo group half of the patients were devoid of nocturnal erections. No signs of ischaemia was seen, but in four patients receiving noradrenaline infusion was stopped due to pain. This treatment seems effective in preventing nocturnal erections after penile surgery.     

Current rehabilitation strategy: clinical evidence for erection recovery after radical prostatectomy

Erectile function (EF) recovery remains a prominent functional outcome underachievement of radical prostatectomy (RP), despite the success of anatomic “nerve-sparing” technique and its recent refinements in the modern surgical era. Delayed (for as much as a few years) or incomplete (partial and unusable) EF recovery commonly occurs in many men still today undergoing this surgery. “Penile rehabilitation”, alternatively termed “EF rehabilitation”, originated formally as a therapeutic practice approximately 15 years ago for addressing post-RP erectile dysfunction (ED) beyond conventional ED management. Although the premise of this therapy is conceptually sound and generally accepted, in reference to the implementation of strategies for promoting EF recovery to a naturally functional level in the absence of erectile aids (distinct from the premise of conventional ED management), the optimal manner and efficacy of currently suggested therapeutic strategies are far less established. Such strategies include regimens of standard ED-specific therapies (e.g., oral, intracavernosal, and intraurethral pharmacotherapies; vacuum erection device therapy) and courses of innovative interventions (e.g., statins, erythropoietin, angiotensin receptor blockers). An endeavor in evolution, erection rehabilitation may ideally comprise an integrative program of sexual health management incorporating counseling, coaching, guidance toward general health optimization and application of demonstrably effective “rehabilitative” interventions. Ongoing intensive discovery and rigorous investigation are required to establish efficacy of therapeutic prospects that fulfill the intent of post-RP erection rehabilitation.     

降钙素基因相关肽在阴茎勃起机制中的作用

通过实验动物（成年雄性狗）研究肽能神经介质──降钙素基因相关肽（ＣＧＲＰ）在勃起机制中的作用。取动物海绵体平滑肌、阴部内动脉、静脉等组织离体灌注并活体海绵体内注射ＣＧＲＰ，证实对离体组织具有舒张作用，以海绵体平滑肌最强。活体海绵体内注射观察动脉血流量增加，海绵体内压升高，阴茎明显胀大。刺激海绵体神经诱导阴茎勃起检测ＣＧＲＰ水平变化，发现在勃起高峰时，海绵体组织内ＣＧＲＰ增高，面消退期血浆内ＣＧＲＰ升高。从而证实ＣＧＲＰ可导致海绵体平滑肌松弛、减少阻力，增快动脉血流，是促使阴茎勃起的主要神经介质之一。在消退期也可能参与使阻闭静脉的开放，加快回流的作用。     

Evaluation of penile perfusion by color-coded duplex sonography in the management of erectile dysfunction

The etiology of erectile dysfunction is wide ranging. Penile vascular disorders may result in impaired erection or complete impotence. Almost 30% of erectile dysfunction is due to the presence of systemic disease which affects the blood supply to the penis. The intracavernosal injection test with prostaglandin E1 alone offers limited information on the vascular status. In accordance with the increasing demand for less invasive procedures, penile color-coded duplex sonography (CCDS) combined with the pharmaco-erection test represents a first-line noninvasive approach to investigate arterial and veno-occlusive function. Peak systolic velocity and a change in cavernous artery diameter are indicators of arterial inflow, while the pathological end diastolic velocity and resistance index point out veno-occlusive dysfunction. The combined investigation of power and standard color Doppler ultrasound may yield more details of penile vascular anatomy.     

Comparison of nocturnal penile tumescence monitoring and cavernosal smooth muscle content in patients with erectile dysfunction

Purpose: Nocturnal penile tumescence monitoring was compared to cavernosal smooth muscle content in 48 cases of erectile dysfunction.Materials and methods: Pre-operatively nocturnal penile tumescence rigidity (NPTR) testing, colour Doppler sonography and if needed pharmaco cavernosometry-cavernosography were evaluated in 48 impotent patients before surgical intervention. The 40 patients whom all those diagnostic tools were abnormal constituted the first group. In the remaining 8 patients, which constitutes the second group, NPTR testing were normal but the other tests were abnormal. 10 potent patients with congenital penile curvature constituted the third group. Cavernous biopsies were obtained during the surgery and biopsies stained immunohistochemically to quantify smooth muscle cells (SMC) by anti-desmin and anti-SMA.Results: We observed statistical significant difference of corporeal SMC content with regard to first Vs second group and first Vs third group (p < 0.05). However we did not observe statistically significant difference with regard to second vs third group (p > 0.05).Conclusion: NPTR testing appears to correlate well with corporeal SMC, which is the key structures of erection. We think that with taking into the consideration of its specific reservations, NPTR testing is still one of the best non-invasive tool in the differential diagnosis of erectile dysfunction.     

可充胀阴茎假体治疗勃起功能障碍的体会

目的：探讨三件套可充胀阴茎假体治疗勃起功能障碍（ED）的疗效。方法：选择5例ED患者，其中50岁以上4例，并发糖尿病3例，高血压动脉粥样硬化1例，另1例为骨盆骨折、尿道断裂伤引起神经性ED。5例均采用三件套可充胀阴茎假体植入术。结果：4例术后伤口如期愈合，能够达到满意的性生活，另1例因阴茎过短，假体植入后，伤口长期不愈合，出现组织排异现象，导致尿道海绵体坏死、穿孔。漏尿而最后不得不取出假体。结论：ED患者植入三件套可充胀阴茎假体，手术切口小，愈合后不易察觉，治疗效果好，患者乐于接受。     

麻醉对泌尿外科术中阴茎勃起的影响

背景 术中阴茎勃起是泌尿外科手术中发生率较低的一种并发症,一旦发生可使手术操作困难.虽然至今对于术中阴茎勃起的机制仍然不完全清楚,但是已有的研究表明麻醉方法和麻醉药可影响术中阴茎勃起的发生和发展. 目的 旨在增加临床医生关于麻醉对术中阴茎勃起影响的认识. 内容 系统阐述了术中阴茎勃起的机制,麻醉方法和麻醉药对术中阴茎勃起的可能影响. 趋向 使用恰当的麻醉方法和麻醉药可有效阻止术中阴茎勃起的发生和发展.     

阴茎勃起硬度的评估

阴茎勃起硬度是完成满意性生活的关键因素之一,也是ED诊断和治疗的重要评价指标。本文回顾阴茎勃起硬度的构成和影响因素,总结常见的硬度评估方法,包括评估客观指标的Rigiscan、轴向弯折试验、阴茎血流彩超,以及评估ED患者主观感受的国际勃起功能问卷表(IIEF)、IIEF勃起功能专项评分(IIEF-EF)、勃起硬度分级(EHS),讨论其特点和临床针对性。     

Morphologic findings and blood flow parameters of penile vasculature in patients with erectile dysfunction

The objective was to study the risk factors in patients with erectile dysfunction in correlation with ultrasound findings of penile vasculature. Patients with erectile dysfunction were classified in four groups according to their risk factors. Group A (37 pts) who were heavy smokers, group B (40 pts) who suffered from diabetes mellitus, group C (30 pts) who suffered from hyperlipidemia and group D (40 pts) with no risk factors. The peak systolic velocity (PSV) was measured after the intracavernous injection of 10 mg alprostadile. Normal values were PSV>35 cm/s and endiastolic venous velocity<4 cm/s. It was found that the mean PSV in group A was 22.2±2.25 cm/s without venous leakage, in group B the mean PSV was 24.6±1.29 cm/s but there was a significant venous leakage (mean end-diastolic velocity 6.2±1.37 cm/s). Patients with hyperlipidemia (group C) had a mean PSV of 26.2±1.74 cm/s and insignificant venous leakage and patients in group D had a normal vascular profile. Patients with erectile dysfunction who are heavy smokers are predisposed to have penile arterial insufficiency, while diabetics have both arterial insufficiency and venous leakage.     

Radiological assessment of penile prosthesis: the role of magnetic resonance imaging

Penile implants offer a dependable way of restoring erections in virtually all motivated patients. The satisfaction rate among both patients and partners using these devices is high. Advances in technology have reduced the infection rate and increased the mechanical reliability of these products. However, too often, urologists do not present this option with the same authority as other treatments. The reason is fear of complications and lack of expertise in managing them. Although they are not very frequent, complications may be catastrophic. The most significant postoperative complication associated with the implant surgery is infection of the device, which is quite frequent, but some other important complications are distal and proximal perforation of the albuginea, SST deformity, S-shaped deformity of the penis, erosion of a component, and mechanical malfunction of the device. The best way to manage complications is to prevent them, but we do not have many diagnostic tools available. Diagnosis is based on clinical history and physical examination, but imaging techniques are also needed to explore the prosthesis in situ to plan the surgical approach if it is needed. In this article we review the different imaging techniques used for the diagnosis of complications of prosthetic surgery of the penis, including conventional radiology, use of sonography, the role of CT scan and the magnetic resonance imaging (MRI) of the penile prosthesis. We conclude that MRI is the most valuable method for the diagnosis of penile prosthesis complications. It is not an ionizing radiation imaging method and has the unique feature among imaging techniques of demonstrating penile anatomy in three orthogonal planes. It is superior to any other imaging method in the definition of soft tissue contrast.     

阴茎脚静脉局部解剖的临床意义

目的 研究阴茎脚静脉的局部解剖，探讨其在静脉性勃起功能障碍中的应用价值。方法 对死亡原因和生前阴茎勃起状况不明的14具福尔马林处理的成年男性尸体的阴茎脚静脉进行解剖，记录每侧阴茎脚静脉数目，分布，与阴茎脚和阴部内动脉、阴茎背动脉、海绵体动脉等结构的关系。结果 14个标本28侧阴茎脚共有101支脚静脉，平均每侧3，6支。根据脚静脉与阴茎脚的关系，脚静脉被分为背侧脚静脉和内腹侧脚静脉。其中背侧脚静脉40支，内腹侧脚静脉61支。17侧(60．7％)内腹侧脚静脉中有一支走行于阴部内动脉、阴茎背动脉、海绵体动脉内侧。结论 阴茎脚静脉数目众多，分布和解剖结构复杂，常规结扎术很难完全结扎，静脉栓塞术可能是治疗阴茎脚静脉痿较好的选择。     

The effect of DA-8159 on corpus cavernosal smooth muscle relaxation and penile erection in diabetic rabbits

A previous study showed that DA-8159, a potent type 5 phosphodiesterase inhibitor, enhanced the relaxation of the smooth muscles in the normal rabbit corpus cavernosum. In this study, we investigated the in vitro effects of DA-8159 on cavernosal smooth muscle relaxation and the in vivo erectogenic potential in diabetic rabbits, since erectile dysfunction is a well-known sequela of diabetes mellitus. Diabetes mellitus was induced in male New Zealand White rabbits with alloxan monohydrate. Cavernosal strips from age-matched control and 8-week diabetic animals were mounted in organ baths. The relaxation responses to sodium nitroprusside (10^-910^-5 M), a nitric oxide donor, were assessed in the presence or absence of DA-8159 (10^-910^-6 M). For the penile erection test, DA-8159 was given orally (1~10 mg/kg) to diabetic rabbits and the length of the uncovered penile shaft was measured in a time-course manner in the presence or absence of intravenous sodium nitroprusside. The sodium nitroprusside-stimulated relaxations were significantly impaired in the corpus cavernosum from the diabetic group (IC₅₀=1.07×10^-6 M following 8 weeks of diabetes mellitus; compared with 0.48×10^-6 M for age-matched controls). DA-8159 significantly and dose-dependently enhanced the sodium nitroprusside-stimulated relaxation in the diabetic groups. In addition, DA-8159 induced a dose-dependent penile erection in diabetic rabbits, which was potentiated by intravenous sodium nitroprusside. These results suggest that DA-8159 is an effective treatment for diabetic erectile dysfunction but further evaluation of the efficacy on human needs to be performed.     

The effect of sildenafil citrate and pentoxifylline combined treatment in the management of erectile dysfunction

Introduction In the present study, we evaluated the efficacy of sildenafil and pentoxifylline combined therapy in the treatment of vasculogenic erectile dysfunction. Methods Sixty-eight patients with various degrees and types of vasculogenic erectile dysfunction were included in the study. The patients were recommended to take oral sildenafil (minimum two 50-mg tablets/week) 1 h prior to sexual intercourse for 4 weeks. After 4 weeks of washout period, patients were recommended to take combined therapy (minimum two 50-mg tablets/week sildenafil 1 h prior to sexual intercourse and 1.2 g of pentoxifylline/day divided into three doses) for an additional 4-week period. Both treatment regimes were evaluated with the international index of erectile function (IIEF). Results Mean IIEF score was higher after sildenafil treatment when compared to pre-treatment score (14.2 ± 4.3 and 8.6 ± 4.2, respectively, P < 0.05). Likewise after the combination treatment, mean IIEF score was higher when compared to pre-treatment score (18.1 ± 5.2 and 8.6 ± 3.8, respectively, P < 0.05). The increase in the IIEF score was 5.62 ± 2.08 in the sildenafil only group whereas increase in the IIEF score was 9.51 ± 3.77 in the combination therapy group. There was a statistically significant increase in the combination group when compared to the sildenafil only group (P < 0.001). Conclusion Our study suggests that use of sildenafil citrate and pentoxifylline combined therapy could be effective in the management of patients with vasculogenic erectile dysfunction.     

Systemic and cavernous plasma levels of endothelin (1-21) during different penile conditions in healthy males and patients with erectile dysfunction

 The role of the sympathetic adrenergic nerves in mediating the constant tone of penile flaccidity and returning the erect penis to its flaccid state is fairly well established. However, it is not yet known whether additional nonadrenergic transmitters are involved in this process. The peptide endothelin-1 (ET-1) may be one of the factors contributing to such a control. Moreover, it has been speculated by various authors that ET-1 might be involved in the pathophysiology of erectile dysfunction. The present study was undertaken to determine whether or not there is a difference in the courses of ET-1/-2 plasma levels registered in systemic and cavernous blood cavities taken from healthy males and patients with ED during different penile conditions (flaccidity, tumescence/rigidity, detumescence). Thirty-two healthy adult males and 25 patients were exposed to visual and tactile erotic stimuli in order to elicit penile tumescence and, in the group of healthy volunteers, rigidity. Whole blood was aspirated from the corpus cavernosum and the cubital vein, and ET-1/-2 was determined in plasma aliquots by means of an enzyme-linked immunoassay (ELISA). Mean systemic and cavernous plasma level of ET-1/-2 in blood samples obtained from the volunteers was 0.2–0.7 fmol/ml. In the healthy males, no changes in ET-1/-2 levels were observed in the systemic and cavernous blood during penile tumescence, rigidity and detumescence. In the group of patients, mean plasma ET-1/-2 levels in the phase of penile flaccidity and detumescence were found to be higher in the systemic circulation than in the cavernous blood (flaccidity: 0.52 ± 0.38 fmol/ml vs. 0.48 ± 0.46 fmol/ml, respectively; detumescence: 0.53 ± 0.33 fmol/ml vs. 0.27 ± 0.11 fmol/ml, respectively). No differences in the plasma courses of ET-1/-2 were found between patients with an organogenic and psychogenic etiology of ED. In the phase of detumescence, the mean ET-1/-2 level was lower in the cavernous blood cavities taken from the patients than in the samples obtained from the healthy males. Our study revealed a difference in the profiles of ET-1/-2 registered in the cavernous blood of healthy subjects and patients with erectile dysfunction. Nevertheless, since this difference seems to be of no physiological significance, our data counteract the hypothesis of an ultimate importance of ET-1 in the control of penile flaccidity and detumescence and do not support speculations regarding an involvement of ET-1 in the pathophysiology of erectile dysfunction.     

Anatomical mapping of lymphatic drainage in penile carcinoma with SPECT-CT: implications for the extent of inguinal lymph node dissection

BACKGROUND: Knowledge regarding the lymphatic drainage pattern of penile cancer is the basis for the extent of inguinal lymph node dissection for this disease. OBJECTIVE: To prospectively analyze the lymphatic drainage pattern of penile carcinoma using SPECT-CT and evaluate the implications for the extent of inguinal lymph node dissection. DESIGN, SETTING, AND PARTICIPANTS: The lymphatic drainage patterns of 50 patients scheduled for dynamic sentinel node biopsy were analyzed using a hybrid SPECT-CT scanner. MEASUREMENTS: A total of 86 clinically node-negative (cN0) inguinal and pelvic regions was evaluated. The sentinel and higher-tier nodes on SPECT-CT were divided into different zones in the groin and pelvic region. The groin was divided according to Daseler's five zones, four zones obtained by drawing a vertical and horizontal line over the saphenofemoral junction and one zone directly overlying this junction. The nodes in the pelvic region were classified into three zones: the external iliac/obturator zone, the common iliac zone, and the paraaortal zone. RESULTS AND LIMITATIONS: Lymphatic drainage was visualised in 82 of the 86 cN0 groins (95.3%). A total of 115 sentinel nodes and 182 higher-tier nodes was found. All sentinel nodes were located in superior and central inguinal zones. The higher-tier nodes were located in the groin and pelvic region. No lymphatic drainage was seen to the inferior two regions of the groin. A potential limitation of the study is that the unilateral lymphatic drainage seen in some patients could be normal, but it could also be caused by blockage of lymphatic drainage due to a grossly involved metastatic lymph node. Another possible limitation is that this study relies on the quality and accuracy of lymphoscintigraphy and the subsequent sentinel node procedure. CONCLUSIONS: All sentinel and higher-tier nodes were located in the superior and central inguinal zones and the pelvic region. No lymphatic drainage to the inferior inguinal zones was seen. This suggests that the extent of inguinal node dissection in cN0 patients could be reduced to removal of the superior and central inguinal zones. This may decrease the extensive morbidity associated with this procedure.