Sacral Neuromodulation for Lower Urinary Tract Dysfunction and Impact on Erectile Function

Penile Erection Morphometry: The Need for a Novel Approach

For many males, sexual function holds significant value in determining their quality of life. Despite the importance of male erectile function, no quantitative method to measure it accurately is currently available. Standardized assessment methods such as RigiScan™, International Index of Erectile Function (IIEF-5), and the stamp test are used to evaluate sexual function, but those methods cannot repetitively and quantitatively measure erectile function. Only direct measurement can quantitatively assess the shape of an erect penis. This paper presents the essential requirements for developing an ideal measurement method for penile erection. It also introduces current approaches for diagnosing male sexual function and reviews ongoing research to quantitatively measure erectile function. The paper further summarizes and analyzes the advantages and disadvantages of each method with respect to the essential requirements. Finally, the paper discusses the future direction toward the development of Penile Erection Morphometry.

[Functional-neurosurgical treatment options for functional pelvic floor disorders : Value of sacral neuromodulation]

BACKGROUND

Sacral neuromodulation is an established minimally invasive therapy indicated for the treatment of functional pelvic floor disorders. While it received its original US Food and Drug Administration (FDA) approval for the treatment of overactive bladder symptoms, it is now regarded as a therapeutic option to treat both urinary/fecal incontinence and retention. In addition, it has proven to be a valuable tool in the treatment of chronic pelvic pain, and preliminary results indicate a potential to elicit improvements in sexual functioning.

OBJECTIVE

This article serves to provide a summary of the therapy and its applications.

METHOD

Selective literature review.

RESULTS

Sacral neuromodulation implants allow for the controlled shifting of the autonomic control of bladder and rectum towards an inhibition or facilitation of voiding, dependent on the patient's needs and under the patient's control. At the same time and depending on the applied stimulation, the implants can interfere with the nerve's conduction of pain signals. This makes them a therapeutic option for pelvic pain that fails to respond to conventional treatment. Finally, there have been first reports suggesting improvements in sexual dysfunction under sacral neuromodulation, thus, potentially opening up a new line of therapy for those disorders.

DISCUSSION

Sacral neuromodulation is a flexible and efficient form of therapy for functional disorders of the pelvic floor. Specifically, the same intervention can treat seemingly contradictory disorders such as urinary/fecal incontinence and retention as well as chronic pain.

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.

[Sacral neuromodulation as treatment of non-neurological vesical emptying disorders]

GOAL

The goal was to evaluate the results of sacral neuromodulation (SNM) in non-neurological vesical emptying disorders.

PATIENTS AND METHODS

From February 2010 to October 2017, 28 patients presenting voiding symptoms or a non-obstructive chronic urine retention without neurological cause have been operated for an SNM (test phase). The test was positive in case of decreased number of proper intermittent self-catheterization (SC) or post-voiding residual urine (PVR) of at least 50 %. A 100 % positive result meant the return to a spontaneous voiding without SC with a non-significative PVR (<100ml).

RESULTS

The median follow-up was of 53.2±21.2 months. Twenty-four (85.7%) tests were positive, from which twenty-two (78.6%) were 100% positive. 16 (84.2%) out of 19 patients with SC had spontaneous voiding without PVR. The number of daily SC decreased from 4.6±1.5 to 0.4±1.2 in post-operative (P<0.001). The PVR was of 287.1±170.4ml vs. 30.4±48.6ml in post-operative (P<0.001). Fourteen patients (58.3%) underwent at least one chirurgical revision or a removal of material ; mainly for loss of efficiency, end of battery, electrode migration and pain on material. At the end of the follow-up, 70.8% of the responding patients had their device still efficient.

CONCLUSION

Results showed that SNM appears to be an efficient treatment of non-neurological emptying vesical troubles. Nevertheless, the re-operation rate was still significant.

LEVEL OF EVIDENCE

3.

Performance and safety of treatment options for erectile dysfunction in patients with spinal cord injury: A review of the literature

BACKGROUND

For a large proportion of patients with spinal cord injury, sexuality and reproduction are important issues. However, sparse data exist regarding available treatment options for this patient population.

OBJECTIVES

We sought to review performance and safety rates of all currently available treatment options for erectile dysfunction in spinal cord injury men.

MATERIALS AND METHODS

A systematic literature review without time restrictions was performed using PubMed/EMBASE database for English-, Italian-, German-, and Spanish-language articles. Articles' selection was performed according to the PRISMA guidelines. Relevant papers on erectile dysfunction in spinal cord injury patients were included in the final analyses.

RESULTS AND DISCUSSION

Overall, 47 studies were eligible for inclusion in this review. Of these, most evidence dealt with phosphodiesterase 5-inhibitors and intracavernous drug injection. Both treatment options are associated with high levels of performance and with patients/partners' satisfaction; side effects are acceptable. Overall, penile prostheses and vacuum erection devices are in general less approved by spinal cord injury patients and are correlated with increased rates of complications in comparison with phosphodiesterase 5-inhibitors and intracavernous drug injection. Sacral neuromodulation, transcutaneous electrical nerve stimulation, and intraurethral suppositories have been poorly studied, but preliminary studies did not show convincing results.

CONCLUSION

The best treatment options for erectile dysfunction in spinal cord injury patients emerged to be phosphodiesterase 5-inhibitors and intracavernous drug injection. The choice of erectile dysfunction treatment should be based on several aspects, including residual erectile function, spinal cord injury location, and patients' comorbidities. Future studies assessing the applicability of less well-studied treatments, as well as evaluating innovative options, are needed in this specific population.

[Sacral neuromodulation in under- and overactive detrusor-quo vadis? : Principles and developments]

BACKGROUND

Sacral neuromodulation (SNM) has been used in the treatment of refractory overactive bladder syndrome, nonobstructive urinary retention and faecal incontinence for almost 40 years now. It is not to be confused with the sacral anterior root stimulation which is exclusively used for bladder dysfunction due to spinal paraplegia.

MECHANISM OF ACTION

The principles of SNM are yet to be fully understood. Nevertheless, there is proof of modulating the activity of several micturition-associated, afferent neurons in the spine, brainstem and cerebrum. Thus, premature detrusor contractions are suppressed, the desire to void is delayed and detrusor-sphincter coordination improves.

TECHNIQUES OF IMPLANTATION AND STIMULATION

Motor reactions are an important indicator of correct electrode placement. The implantation procedure consists of two stages with an initial trial phase to determine the best possible treatment response through an external generator before implanting the whole stimulating device. Yearly check-up examinations are recommended; wireless adjustments allow for long-lasting symptom reduction.

INDICATION AND OUTCOME

Success rates in the treatment of the refractory overactive bladder syndrome and the non-obstructive urinary retention lie above 70% and can still be perceived as sufficient after 5 years of ongoing SNM therapy. There is also profound evidence of SNM being an effective option for patients with faecal incontinence or chronic obstipation.

CONTRAINDICATIONS AND RISKS

Children, pregnant women and patients in need of frequent MRI examinations are usually not eligible for SNM therapy. Infection of the implant, technical failure (including lead displacement and battery depletion) and pain in the implantation site are important adverse effects which might require surgical revision.

CONCLUSIONS

The indications for SNM in the German health care system can be expected to be expanded upon the chronic pelvic pain syndrome, erectile dysfunction and additional gastrointestinal conditions. Technical progress will continue to improve the risk-benefit ratio of SNM.

Pathogenic mechanisms linking benign prostatic hyperplasia, lower urinary tract symptoms and erectile dysfunction

INTRODUCTION

Erectile dysfunction (ED) and lower urinary tract symptoms (LUTS) caused by benign prostatic hyperplasia (BPH) are clinical entities very prevalent in men aged over 50 years. There is evidence that both may have a common pathophysiology.

OBJECTIVE

The objective of this study was to conduct a literature review aiming to show theories and hypotheses that justify a single pathophysiology for ED and LUTS/BPH.

METHODS

A search in Medline using the keywords of the Medical Subject Headings (MESH) 'erectile dysfunction' and 'lower urinary tract symptoms' in all fields of the database up to 15 December 2012. This search found 198 relevant articles that were analyzed.

RESULTS

The data and articles were divided according to the type of evidence found. There are strong epidemiological data showing that LUTS/BPH is a risk factor for developing ED. Several experimental models demonstrated partial obstruction of the bladder in animals causes voiding disorders as well as a negative impact on erectile function of the operated animals. The increased adrenergic tonus in animals leads to prostate growth and urodynamic conditions similar to those found in men with LUTS and ED. Arteriosclerosis may lead to loss of vesical complacency, urinary tract obstruction and fibrosis of the cavernous bodies. The use of phosphodiesterase type 5 inhibitors (PDE-5i) and/or alpha-adrenergic blockers to treat ED and LUTS/BPH reinforces the hypothesis that, at least in some patients, both clinical pictures may have the same pathophysiology.

Surgical access for electrical stimulation of the pudendal and dorsal genital nerves in the overactive bladder: a review

PURPOSE

The anatomy of the pudendal nerve and its nerve branches, especially the dorsal nerve of the penis and clitoris (dorsal genital nerves), and the clinical application of electrical stimulation of these nerves in patients with overactive bladder syndrome and detrusor overactivity are reviewed.

MATERIALS AND METHODS

A literature search was performed using the PubMed® database and reference lists of relevant studies to obtain articles concerning the anatomy as well as the electrical stimulation of the pudendal nerve and its nerve branches in patients with overactive bladder syndrome.

RESULTS

According to the anatomy, electrical stimulation of the pudendal nerve and the dorsal genital nerves to suppress involuntary detrusor contractions is possible at several sites along their course from the sacral nerves to the penis or clitoris. The nerves are accessible by minimally invasive percutaneous methods. Stimulation of the pudendal nerve and dorsal genital nerves effectively increases bladder capacity, and inhibits involuntary detrusor contractions and overactive bladder symptoms.

CONCLUSIONS

More clinically applied studies are recommended for stimulation of the dorsal genital nerves to assess its value and feasibility because most studies have been performed in an acute and experimental setting. The preferred type of electrode is not known, but if wire electrodes can be implanted and fixated well by a minimally invasive procedure, cuff electrodes are not necessary. Before deciding on continuous or conditional stimulation, chronic clinical studies are recommended because acute studies remain inconclusive. The feasibility of conditional stimulation depends on the availability of a reliable and clinically applicable detrusor activity sensor.

Autonomic-somatic communications in the human pelvis: computer-assisted anatomic dissection in male and female fetuses

Sphincter continence and sexual function require co-ordinated activity of autonomic and somatic neural pathways, which communicate at several levels in the human pelvis. However, classical dissection approaches are only of limited value for the determination and examination of thin nerve fibres belonging to autonomic supralevator and somatic infralevator pathways. In this study, we aimed to identify the location and nature of communications between these two pathways by combining specific neuronal immunohistochemical staining and three-dimensional reconstruction imaging. We studied 14 normal human fetal pelvic specimens (seven male and seven female, 15-31 weeks' gestation) by three-dimensional computer-assisted anatomic dissection (CAAD) with neural, nitrergic and myelin sheath markers. We determined the precise location and distribution of both the supra- and infralevator neural pathways, for which we provide a three-dimensional presentation. We found that the two pathways crossed each other distally in an X-shaped area in two spatial planes. They yielded dual innervation to five targets: the anal sphincter, levator ani muscles, urethral sphincter, corpus spongiosum and perineal muscles, and corpora cavernosa. The two pathways communicated at three levels: proximal supralevator, intermediary intralevator and distal infralevator. The dorsal penis/clitoris nerve (DN) had segmental nitrergic activity. The proximal DN was nNOS-negative, whereas the distal DN was nNOS-positive. Distal communication was found to involve interaction of the autonomic nitrergic cavernous nerves with somatic nitrergic branches of the DN, with nitrergic activity carried in the distal part of the nerve. In conclusion, the pelvic structures responsible for sphincter continence and sexual function receive dual innervation from the autonomic supralevator and the somatic infralevator pathways. These two pathways displayed proximal, intermediate and distal communication. The distal communication between the CN and branches of the DN extended nitrergic activity to the distal part of the cavernous bodies in fetuses of both sexes. These structures are important for erectile function, and care should therefore be taken to conserve this communication during reconstructive surgery.

Future indications for sacral nerve stimulation

AIM

The aim of this article was to determine the effect of sacral nerve stimulation (SNS) on the treatment of faecal incontinence, constipation, irritable bowel syndrome, mixed urinary and bowel disorders, spinal injury and neurodegenerative disease, pain syndromes, and sexual dysfunction.

METHOD

A Medline search was performed including the keywords and/or MeSH headings of 'sacral nerve stimulation', 'neuromodulation', 'artificial pacemaker', 'faecal incontinence', 'constipation' and 'anal pain'. Further studies were identified by cross-referencing from relevant articles and by appraisal of recent peer-reviewed conference abstracts and proceedings.

RESULTS

SNS has been used for the treatment of urinary, bowel and sexual dysfunction, as well as pain resulting from such disorders, and dysfunction arising from nerve injury and degenerative disease. There is a paucity of high quality evidence to support the use of SNS for the majority of novel indications at present.

CONCLUSION

Good quality prospective, cross-over studies are required to determine the true benefits of SNS. Further research into patient selection, operative technique and stimulation parameters for existing indications will ensure a place for SNS in the future treatment algorithm of functional pelvic floor disorders.

Clinical concomitant benefits on pelvic floor dysfunctions after sacral neuromodulation in patients with incomplete spinal cord injury

OBJECTIVES

To assess the concomitant clinical improvement in incomplete spinal cord injury patients (SCIPs) suffering from neurogenic bowel symptoms (NBSs), neurogenic lower urinary tract symptoms (NLUTSs) and neurogenic erectile dysfunction (NED) using sacral neuromodulation (SNM) for NBSs and NLUTSs.

METHODS

Seventy-five SCIPs were selected. Before and during the follow-ups post-SNM, NLUTSs and NBSs were detected mainly through specific diaries. Erectile function was assessed using the International Index of Erectile Function composed of 5 questions (IIEF5). Quality of life (QoL) was measured with the Short Form 36 Health Survey questionnaire (SF-36). During the first stage, in which a permanent electrode was inserted percutaneously into the third sacral foramina and stimulated using an external generator, patients with NBSs or NLUTSs were required to improve their symptoms by at least 50% compared with baseline before proceeding to the second stage in which the generator was placed in the patient's buttock. NED patients needed to increase their IIEF5 score by at least 25% compared with baseline (evaluated initially 3 months after the second stage) in order to continue follow-up.

RESULTS

Fourteen out of 37 subjects who manifested two functional pelvic dysfunctions at baseline maintained notable clinical improvement in two pelvic functions (median follow-up >3 years). Six had non-obstructive retention (NOR) and NED, six double incontinence, and two constipation with NOR. In the general and mental health domains of the SF-36, all patients improved their scores by at least 20% compared with baseline.

CONCLUSIONS

SNM may be beneficial to selected incomplete SCIP with concomitant pelvic functional disturbances.

Sacral nerve modulation in overactive bladder

This article represents a general overview of therapies for urinary urgency, frequency, and overactive bladder, with specific emphasis on sacral neuromodulation. The history of sacral neuromodulation is discussed along with an update of the current literature. Future directions for neuromodulation of the pelvic floor also are discussed.

Clinical outcome of sacral neuromodulation in incomplete spinal cord-injured patients suffering from neurogenic bowel dysfunctions

STUDY DESIGN

Retrospective study.

OBJECTIVES

Efficacy and safety of sacral neuromodulation (SNM) in incomplete spinal cord-injured patients (SCIPs) affected by chronic neurogenic bowel symptoms (NBSs).

SETTING

Neurourology Department. Primary to tertiary care.

METHODS

Retrospective non-blinded study without controls. Thirty-nine SCIPs were submitted to temporary stimulation for NBS. Permanent implantation was carried out if both their NBSs improved and the Wexner questionnaire scores were reduced by at least 50% during the first stage compared with that at baseline. Outcome measures included episodes of fecal incontinence and number of evacuations per week, as well as the Wexner score and the Short Form 36 (SF-36) Health Survey questionnaire.

RESULTS

Twenty-three SCIPs were submitted to definitive SNM, maintaining their clinical benefits after permanent implantation with a median follow-up of 38 months. The length of time since neurological diagnosis to SNM therapy represents the only factor related to the success of the implantation, P<0.05. In subjects with constipation (12), the median number of evacuations shifted from 1.65 to 4.98 per week, whereas the Wexner score changed from 19.91 to 6.82 in the final checkup with P<0.05. In subjects with fecal incontinence (11), the median number of episodes per week in the final follow-up was 1.32 compared with 4.55 pre-SNM. The general and mental health of both groups was measured with the SF-36 questionnaire and consistently showed statistical improvement (P<0.05).Anorectal manometry showed no important variation compared with baseline. There were no major complications.

CONCLUSIONS

SNM therapy should be considered for the treatment of NBS for select patients with incomplete spinal cord injury when conservative treatments fail.

The associations among eNOS G894T gene polymorphism, erectile dysfunction, and benign prostate hyperplasia-related lower urinary tract symptoms

INTRODUCTION

A number of literature has now identified the role of impaired nitric oxide synthase/nitric oxide pathway in the endothelium as the central to the development of erectile dysfunction (ED) and benign prostate hyperplasia-related lower urinary tract symptoms (BPH/LUTS). Recently a few studies have reported the associations between endothelial nitric oxide synthase (eNOS) G894T gene polymorphisms and ED. However, there has been no report investigating the eNOS G894T genetic susceptibility factor for both ED and BPH/LUTS.

AIM

To investigate the possible associations among eNOS G894T polymorphism, ED, and BPH/LUTS in a Taiwanese population.

MAIN OUTCOME MEASURES

Patients with ED were defined as those having a 5-item International Index of Erectile Function-5 <21.

METHODS

In all, 372 Taiwanese men underwent a free health screening were enrolled. All the men had complete clinical data and questionnaires taken. The eNOS G894T polymorphisms were determined using the polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

Three hundred seventy-two men had a mean (standard deviation) age of 60.2 (8.8) years. With multivariate analysis, our data identified that aging, diabetes mellitus (DM), and eNOS G894T gene polymorphism were three independent common risk factors for both ED and BPH/LUTS (P < 0.001, P = 0.036, and P = 0.039 for ED; P = 0.034, P = 0.004, and P = 0.016 for BPH/LUTS, respectively). The eNOS 894T allele carriers had significantly higher prevalence of ED (77.9% vs. 60.4%, P = 0.012) and higher International Prostate Symptom score (IPSS) (13.3 +/- 10.7 vs. 9.3 +/- 7.8, P = 0.001) than G allele carriers.

CONCLUSIONS

Our results showed that aging, DM, and eNOS 894T allele carrier gene polymorphism were the three independently common risk factors for both ED and BPH/LUTS in the Taiwanese population. The eNOS 894T allele carriers had significantly higher frequencies of ED and higher IPSS, suggesting that eNOS G894T gene polymorphisms may play an implication as a genetic susceptibility factor for both ED and BPH/LUTS.