Bulbocavernosus reflex studies and autonomic testing in the diagnosis of erectile dysfunction

Diagnostic work up: Laboratory and biomarkers

This chapter will focus on the diagnostic work around sexual dysfunction in Parkinson's disease, especially laboratory tests and biomarkers. A number of methods to analyze if sexual dysfunction is caused by neural pathology, vascular dysfunction or other mechanisms are now available. Other methods can be used to differentiate between psychogenic/functional reasons behind sexual dysfunction and organic ones. The role of biomarkers for diagnosis, but also for understanding the reason behind and for counteracting sexual dysfunction is becoming more evident. There is also a rich and increasing number of scales and other instruments available for detecting and quantifying sexual hypo- and hyperactivity. When investigating the reason behind sexual dysfunction in patients with Parkinson's disease comorbidities should also be considered. Finally, early and pronounced sexual dysfunction might in some cases be an indication that differential diagnosis, like Multisystem Atrophy, should be thought about. All these aspects of the diagnostic procedures around sexual dysfunction in Parkinson's disease will be covered in this chapter.

Midline sensory nerve supply to the anoscrotal junction: a study using human male fetuses

The origin of the posterior scrotal nerve is considered to be the bilateral pudendal nerves but the course to the midline is still obscure. Using 5 late-stage human male fetuses, we identified the single nerve through the intramuscular midline septum of the bulbospongiosus and the bilateral nerves along the left and right sides of the septum. Thus, the posterior scrotal nerve showed a variation: a single midline trunk or bilateral nerves. Branches of the bilateral pudendal nerves ran medially between the muscle and Cowper's gland and, at the midline area, they joined or associated closely. During the proximal course, much or less, the nerve penetrated the superior part of the muscle. The nerve entered the subcutaneous tissue at and near the perineal raphe. The communication with intrapelvic autonomic nerves were suggested behind Cowper's gland. Notably, the midline skin immediately anterior to the anus carried a considerable dense supply of thin sensory nerves. However, these nerves seemed to come from a space between the rectal smooth muscle and the external anal sphincter, not from the posterior scrotal nerve. Therefore, surgical treatment of the intersphincteric layer was likely to injure the original sensory nerve supply to the anterior anal skin.

Sympathetic skin response in patients with vascular erectile dysfunction

PURPOSE

We aimed to investigate the utility of sympathetic skin response (SSR) test for evaluating vasculogenic erectile dysfunction (ED) which is the most common type of impotence.

MATERIALS AND METHODS

Men in the age group of 28 to 60 years and suffering from vasculogenic ED, as confirmed by a papaverin test and color Doppler sonography, at least for 6 months referred from our university urology department were included. We used the International Index of Erectile Function (IIEF-5) for grading severity of dysfunction and recorded the SSR of every patient from the median, tibial, and dorsal nerves of the penis. One-way analysis of variance (ANOVA), independent t-test and Pearson's correlation coefficient were used for comparing quantitative variables, and Fisher's Exact test was used for comparing qualitative variables. The Mann-Whitney U Test and the Kruskal-Wallis test were performed for analysis of data that were not normally distributed. A p value of less than 0.05 was considered significant.

RESULTS

Forty-two patients were recruited for the study. We found a strong statistical relationship between the IIEF score and the pathologic SSR registered from every mentioned nerve. Patients with abnormal SSR had more severe ED according to IIEF score (p<0.001). In addition, the IIEF score had a significantcorrelation with diabetes mellitus and cardiovascular disease (t-test; p<0.05).

CONCLUSIONS

Our results confirmed the presence of autonomic dysfunction in patients with vasculogenic impotence via an SSR test. We suggest evaluating the efficacy of the SSR test in patients with vascular impotence for treatment response monitoring in future studies.

The elecrophysiological bulbocavernosus reflex test in female dogs: Its technique and applicability

The intent of the study was to clarify the technique and the application of the electrophysiological bulbocavernosus reflex (EBCR) test in healthy female dogs. For this aim, 15 healthy female dogs were used in the study. The stimulations were made on the clitoris and the responses were recorded from the right side of the external anal sphincter muscle with a concentric needle recording electrode. The EBCR had response latencies between 18.99 and 25.69ms with the mean value of 22.26ms. The EBCR reflex test is not yet widely used for the evaluation of the functional integrity of sacral spinal cord segments and nerve roots in veterinary clinics. Our experiences indicated that the EBCR reflex test gives valuable data about sacral spinal reflex arc functionality and can be accepted as a routine diagnostic method in small animal clinics for evaluation of the sacral reflex arc.

The application of an electrophysiological bulbocavernosus reflex test in male dogs

The electrophysiological bulbocavernosus reflex test consists of recording the electromyographic activity of the bulbocavernosus muscle following electrical stimulation of the glans penis. This study has been carried out to show the applicability of the electrophysiologic bulbocavernosus reflex (EBCR) in dogs and to determine its normal latency value. Ten healthy male dogs were used. Responses to stimulation of the bulbus glandis were recorded from the left bulbocavernosus muscle with a concentric needle-recording electrode. In 10 dogs of maximum size 31 kg and maximum age 3 years, EBCR had response latencies between 17.6 and 28.8 ms with the mean value of 24.4 ms. The results of this study show that the electrophysiological bulbocavernosus reflex test could be employed as a routine diagnostic method in small animal clinics for evaluation of the sacral reflex arc. Among several advantages are easy applicability and the objective result, with the latency exceeding 29 ms not being seen in the dogs used in our study.

Effect of neonatal circumcision on penile neurologic sensation

OBJECTIVES

To evaluate penile sensory thresholds in neonatally circumcised and uncircumcised men.

METHODS

We evaluated 125 patients, 62 uncircumcised men and 63 neonatally circumcised men. All patients completed the Erectile Function domain of the International Index of Erectile Function questionnaire. Of the 125 patients, 29 (International Index of Erectile Function score of between 25 and 30) were placed in the functional group, and 96 in the dysfunctional group. The patients were tested on the dorsal midline glans of the penis (foreskin retracted). Quantitative somatosensory testing was performed and included vibration, pressure, spatial perception, and warm and cold thermal thresholds.

RESULTS

In the functional group, t-test analysis demonstrated a significant (P <0.001) difference, with worse vibration and better pressure sensation for uncircumcised men. When controlling for age, hypertension, and diabetes, all t-test significance was lost. In the dysfunctional group, circumcised men (49 +/- 16 years) were significantly younger (P <0.01) than uncircumcised men (56 +/- 13 years). For the dysfunctional group, t-test analysis also demonstrated worse vibration sensation for uncircumcised men (P <0.01). Again, when controlling for age, hypertension, and diabetes, all t-test significance was lost.

CONCLUSIONS

We present a comparative analysis of uncircumcised and circumcised men using a battery of quantitative somatosensory tests that evaluate the spectrum of small to large axon nerve fiber function. Our study controlled for factors, including age, erectile function status, diabetes, and hypertension, that have been shown to alter neurologic testing. In our study of neonatally circumcised men, we demonstrated that circumcision status does not significantly alter the quantitative somatosensory testing results at the glans penis.

A combined urodynamic and electrophysiological study of diabetic cystopathy

AIMS

The aim of this study is to compare urodynamics and electrophysiological studies in the diagnosis of diabetic cystopathy.

MATERIALS AND METHODS

In this prospective study are included twenty six patients with diabetes mellitus diagnosed at least since 5 years; 17 patients with diabetes type II and 9 with type I. They were divided in two groups in respect to lower urinary tract symptoms (LUTS) and signs suggestive of lower urinary tract dysfunction (LUTD) according to the ICS standardization. Patients with LUTS/LUTD were included in Group A and patients without LUTS/LUTD in Group B. Patients underwent different studies: urodynamic, somatosensory evoked potentials (SSEP) of tibial and pudendal nerves, bulbocavernosus reflex (BCR), bulbocavernosus muscles' electromyography and motor evoked potentials after transcranial magnetic stimulation to indirectly investigate bladder's innervation.

RESULTS

Abnormal urodynamics were found in 13 patients of group A (92.9%) and in 5 of group B (47.1%). This difference was statistically significant (P=0.009). Abnormally prolonged latency of P40 of tibial SSEP was found in 11 patients of group A (78.6%) and in 4 of group B (33.3%) and this difference was also statistically significant (P=0.04). Differences between the two groups concerning: i) peripheral polyneuropathy; ii) pudendal SSEP, iii) dysfunction of central nervous system and iv) abnormal BCR were not statistically significant.

CONCLUSION

The study of tibial SSEP is an easily performed test and it is well correlated to abnormal urodynamics in diabetic patients with and without LUTD/LUTS.

THE ROLE OF SILDENAFIL IN THE TREATMENT OF ERECTILE DYSFUNCTION IN PATIENTS WITH PELVIC FRACTURE URETHRAL DISRUPTION

PURPOSE

Erectile dysfunction (ED) is a common sequel of pelvic fracture urethral disruption (PFUD). After repair of the urethral injury ED may be the most devastating long-term effect for the patient. Some patients with ED may regain normal erectile function. We prospectively studied the response to sildenafil and the erectile function of patients with ED due to PFUD.

MATERIALS AND METHODS

The erectile function of patients referred to us with PFUD for urethroplasty were prospectively evaluated before surgery. Patients underwent nocturnal penile tumescence testing and, if results were abnormal, penile duplex ultrasonography with intracavernous injection and arteriography were performed to diagnose the etiology of ED. Patients were questioned about erectile function every 3 months after surgery and if they complained of ED they were offered 100 mg sildenafil. Patients were followed for at least 18 months after surgery.

RESULTS

A total of 29 consecutive patients were evaluated and 22 (76%) of them had ED before surgery. Sufficient followup was available for 15 of the patients. Overall 47% of these patients responded favorably to sildenafil. Of the patients 60% with neurogenic ED and 20% of those with arterial ED responded to this treatment. In 33% of the patients ED resolved within the followup period. All patients with spontaneous resolution of ED previously responded to sildenafil (71% of sildenafil responders).

CONCLUSIONS

In patients with ED due to PFUD, those with neurogenic ED are more likely to respond to sildenafil than those with arterial damage. Favorable response to sildenafil may predict spontaneous resumption of normal erectile function over time.

Implications of diabetes mellitus in urology

The incidence of DM is rapidly growing among Americans. DM will rival cancer and heart disease in terms of cost and suffering. The National Institute of Health is tripling the research dollars that are spent on diabetic-related research in an attempt to combat this disease. Urologists are on the front line in the diagnosis and treatment of the complications of DM. The complications of DM that we reviewed in this article, diabetic cystopathy and diabetic ED, can occur in the early stage of DM and often progress in a silent fashion. More awareness and interest are needed to improve our understanding of diabetic complications in urology. Exciting new approaches in the treatment of diabetic cystopathy and ED are being investigated.

The neuropathy of erectile dysfunction

These studies were intended to explore the relationship between autonomic neuropathy and erectile dysfunction (ED). Sensory thresholds reflecting the integrity of both large diameter, myelinated neurons (ie pressure, touch, vibration) and small diameter axons (ie hot and cold thermal sensation) were determined on the penis and finger. Data were compared across subjects with and without ED, controlling for age, hypertension and diabetes. The correlation of specific thresholds scores and IIEF values were also examined. Seventy-three patients who visited the academic urology clinics at Montefiore hospital were evaluated. All patients were required to complete the erectile function domain of the International Index of Erectile Function (IIEF) questionnaire: 20 subjects had no complaints of ED and scored within the 'normal' range on the IIEF. Patients were subsequently tested on their index finger and glans penis for vibration (Biothesiometer), pressure (Semmes-Weinstein monofilaments), spatial perception (Tactile Circumferential Discriminator), and warm and cold thermal thresholds (Physitemp NTE-2). Sensation of the glans penis, as defined by the examined sensory thresholds, was significantly diminished in patients with ED and these differences remained significant when controlling for age, diabetes and hypertension. In contrast, thresholds on the index finger were equivalent in the ED and non-ED groups. Threshold and IIEF scores were highly correlated, consistent with an association between diminished sensation and decreasing IIEF score (worse erectile functioning). These relations also remained significant when controlling for age, diabetes and hypertension. The findings demonstrate dysfunction of large and small diameter nerve fibers in patients with ED of all etiologies. Further, the neurophysiologic measures validate the use of the IIEF as an index of ED, as objective findings of sensory neuropathy were highly correlated with worse IIEF scores. The sensory threshold methods utilized represent novel, non-invasive and relatively simple procedures, which can be used in a longitudinal fashion to assess a patient's neurological response to therapies.

Neurogenic erectile dysfunction

Penile erection is a neurovascular event modulated by psyche and hormones. Erectile dysfunction (ED) has been classified as psychogenic, arteriogenic, neurogenic, endocrinologic, and cavernosal, based on the organs that are involved in penile erection. Among these types, neurogenic ED may be the most common, probably because a deficiency of neurotransmitters is the final common pathway in many diseases and conditions. This review discusses the physiology, pathophysiology, diagnosis, and treatment of erectile function and dysfunction, as well as strategies for future research.

Neurologic erectile dysfunction

Neurologic erectile dysfunction presents a diagnostic and treatment challenge to the internist and urologist. Multiple chronic disease modalities and traumatic etiologies exist. Education regarding these conditions and a detailed and thorough history and office work-up are the best resources for the clinician. Treatment can follow the model of proceeding from the least to most invasive procedure (process of care), taking into account patient and partner satisfaction. Because the psychology of grief and loss may enter into treatment of some neurologic conditions (e.g., erectile dysfunction after radical retropubic prostatectomy, spinal cord injury, or chronic diseases), a whole-patient approach encompassing psychotherapy is warranted.