Seminal emission by electrical stimulation of the spermatic nerve and epididymis

The spermatic nerve and epididymis were stimulated electrically in dogs to elucidate the possibility of artificial seminal emission after bilateral transection of the hypogastric nerves and sympathetic trunks. Before transection, electrical stimulation of a distal end of the severed spermatic nerve caused a trace amount of emission in two dogs and no emission in the remaining four. In contrast, 1 month after the transection, stimulation of a distal end of the severed spermatic nerve caused seminal emission in all six dogs examined, with full seminal volume in four dogs and partial volume in the remaining two. Anatomically, sympathetic nerves originating from the upper portion of the lumbar sympathetic ganglia descended along the spermatic arteries to the testes as spermatic nerves. The present results indicate that spermatic nerves have the potential to generate seminal emission as a compensatory pathway after bilateral transection of the hypogastric nerves. Both direct and percutaneous electrical stimulation of epididymal tails resulted in a full volume of seminal emission in all dogs with transection of both hypogastric nerves and lumbosacral sympathetic trunks as well as in unoperated controls, while high voltage (8 V vs 40-80 V) was required to cause seminal emission by electrical stimulation on the skin surface. Direct stimulation of epididymal tails in men undergoing orchidectomy as treatment for prostatic carcinoma or during biopsy of the contralateral testis in a patient with a testicular tumour, resulted in seminal emission in all five epididymides examined either from the end of the severed vas deferens or in the posterior urethra if the vas deferens was not severed.     

Vagus nerve stimulation for the management of seizures in children: an 8-year experience

Background

Medication-resistant seizure disorder is a challenging, debilitating, and expensive condition. Although multiple interventions are now available, none is universally effective. In 1997, vagus nerve stimulation (VNS) was approved for treatment of refractory seizures in patients older than 12 years. Vagus nerve stimulation has shown some benefit for these individuals, but less is known about its use in patients younger than 12 years. This review analyzes the safety and efficacy of VNS in young children.

Methods

From March 2000 to February 2008, patients with medication-resistant seizures were implanted with a neurocybernetic prosthesis. Two weeks later, the device was activated. The children were followed for at least 3 months, and adjustments were made. Retrospective chart review was performed to collect data.

Results

Of 28 patients, the mean age at implantation was 8 years and 5 months. Twenty-one (75%) children were younger than 12 years. There were no surgical complications. Two children were reimplanted for lead malfunction, and 4 generators were replaced. Two children had transitory adverse effects (hoarseness and stridor). Mean follow-up was 3 years and 5 months. At 1 year, 52% of children had greater than 50% reduction in seizures.

Conclusions

Although the effectiveness of VNS is variable and unpredictable, safety is high even in young children. Because of the potential benefit for these complex patients, the implantation of this nerve stimulation device should be included in the armamentarium of pediatric surgeons.     

Transcutaneous mechanical nerve stimulation using perineal vibration: a novel method for the treatment of female stress urinary incontinence

PURPOSE: We defined basic guidelines for transcutaneous mechanical nerve stimulation in modifying pelvic floor responses in women and determined the efficacy of transcutaneous mechanical nerve stimulation in treating stress urinary incontinence. MATERIALS AND METHODS: Perineal and clitoral transcutaneous mechanical nerve stimulation was performed in healthy volunteers while measuring changes in peak urethral pressure to determine optimal vibration amplitude and site of stimulation. Perineal transcutaneous mechanical nerve stimulation was then performed weekly for 6 weeks in a cohort of women with stress urinary incontinence (33). Reduction in incontinence episodes and pad use on voiding diary were compared from baseline to 6 weeks. Global efficacy was determined at 6 weeks and 3 months after the completion of the program. RESULTS: In healthy subjects a vibration amplitude of 2.0 mm resulted in the highest urethral pressure increase. Although the increase with perineal transcutaneous mechanical nerve stimulation was lower than that seen with clitoral stimulation (80 vs 115 cm H(2)O), perineal transcutaneous mechanical nerve stimulation was more acceptable to the patient and resulted in a better subjective response. Urethral pressure increases with transcutaneous mechanical nerve stimulation at either site were greater than with voluntary contraction (60 cm H(2)O). After 6 weeks of transcutaneous mechanical nerve stimulation in the subjects with stress urinary incontinence, there was a significant reduction in daily incontinence episodes (2.6 +/- 1.1 vs 0.5 +/- 1.1, paired t test p <0.001) and pad use (3.5 +/- 0.9 vs 0.6 +/- 1.3, paired t test p <0.001). At 6 weeks the cure rate (no incontinence episodes) was 73%, with durability through 3 months with 67% still reporting persistent resolution. CONCLUSIONS: Perineal transcutaneous mechanical nerve stimulation has promise as a noninvasive and well tolerated method of treating stress urinary incontinence.     

Long term results of neuromodulation by sacral nerve stimulation for lower urinary tract symptoms: a retrospective single center study

OBJECTIVE: To analyse the influence of technical improvements of Sacral Nerve Stimulation (SNS) on the incidence of surgical interventions and subjective long-term results of SNS. METHODS: Retrospective, transversal study analyzing records of implanted patients at our department of Urology. RESULTS: Of 149 patients analyzed, 107 had overactive bladder symptoms and 42 had urinary retention. Mean follow-up was 64,2 (sd = 38,5) months. In the whole group 194 adverse events occurred. 6 Patients had infection in their implanted system, one was explanted for infection. Most events could be solved by giving advice or by reprogramming the stimulator. 129 reoperations have been performed and 21 patients had their system explanted. Analysis of the data shows a striking difference in the incidence of reoperations, but small differences in subjective results in the groups of patients implanted before or after 1996, suggesting that a proactive approach towards adverse events is worthwhile. CONCLUSIONS: SNS gives lasting benefit in patients with refractory symptoms of overactive bladder and non-obstructive urinary retention. The differences in outcomes and incidence of reoperation can be attributed to the learning curve and technical and surgical improvements in the application of SNS.     

Minimally-invasive electrical stimulation of the pudendal nerve: a pre-clinical study for neural control of the lower urinary tract

AIMS: Electrical stimulation of afferent pudendal nerve fibers can evoke sustained bladder contractions (SBC) in cats, yet evidence of therapeutic efficacy in human subjects is lacking. This pre-clinical study was undertaken to test the hypothesis that robust bladder contractions can be generated with a minimally-invasive needle electrode. MATERIALS AND METHODS: In seven adult cats, triggered electromyographic (EMG) signals from the external anal sphincter (EAS) were used to minimize the needle-to-nerve distance; while reflex bladder contractions were recorded as 20-sec trains of current pulses of varying amplitude (threshold to 10 mA) and frequency (1-100 Hz) were applied to the nerve. This stimulation paradigm was repeated at successively greater needle-to-nerve distances (0.5 cm intervals) and also at different electrode positions along the nerve. RESULTS: Electrophysiological access to the pudendal nerve was consistently achieved, as indicated by the average threshold for EAS activation (0.31+/-0.19 mA). Using different combinations of stimulus amplitude and frequency, robust SBCs were evoked in every experiment. More rostral electrode positions exhibited stimulation amplitudes and corresponding maximum bladder pressures (0.68+/-0.36 mA and 25.3+/-3.5 cmH2O, respectively) that were comparable to those of more invasive stimulation methods. CONCLUSIONS: The needle electrode provides a minimally-invasive approach that will enable the study of reflexes mediated by pudendal afferents in humans, and allow pre-operative testing before implanting a permanent device.     

Predictive factors for successful sacral nerve stimulation in the treatment of faecal incontinence: results of trial stimulation in 200 patients

Aim Sacral nerve stimulation (SNS) has a place in the treatment algorithm for faecal incontinence (FI). However, after implantation, 15–30% of patients with FI fail to respond for unknown reasons. We investigated the effect of SNS on continence and quality of life (QOL) and tried to identify specific predictive factors of the success of permanent SNS in the treatment of FI. Method Two hundred consecutive patients (six men; median age = 60; range 16–81) underwent permanent implantation for FI. The severity of FI was evaluated by the Cleveland Clinic Score. Quality of life was evaluated by the French version of the American Society of Colon and Rectal Surgeons (ASCRS) quality of life questionnaire (FIQL). All patients underwent a preoperative evaluation. After permanent implantation, severity and QOL scores were reevaluated after six and 12 months and then once a year. Results The severity scores were significantly reduced during SNS (P = 0.001). QOL improved in all domains. At the 6‐month follow‐up, the clinical outcome of the permanent implant was not affected by age, gender, duration of symptoms, QOL, main causes of FI, anorectal manometry or endoanal ultrasound results. Only loose stool consistency (P = 0.01), persistent FI even though diarrhoea was controlled by medical treatment (P = 0.004), and low stimulation intensity (P = 0.02) were associated with improved short‐term outcomes. Multivariate analysis confirmed that loose stool consistency and low stimulation intensity were related to a favourable outcome. Conclusion Stool consistency and low stimulation intensity have been identified as predictive factors for the short‐term outcome of SNS.     

Sacral nerve stimulation for faecal incontinence: response rate,satisfaction and the value of preoperative investigation in patient selection

Objective Before undergoing sacral nerve stimulation (SNS) for faecal incontinence (FI), patients are investigated with morphologic, dynamic and electrophysiologic tests. The purpose of our study was to evaluate their value in the selection of patients who may benefit most from neuromodulation. Method If temporary stimulation resulted in a good objective response, a permanent neuromodulator was implanted. Patients were reviewed at 3 months and then at 6 monthly intervals. Asked by telephone, patient’s satisfaction was described as good, satisfactory or poor. Results Forty‐five consecutive patients (41 females, median age 59 years) with FI (Wexner 16.1 ± 2.9) underwent SNS. Temporary stimulation was successful in 32 (71)% patients. At a median follow‐up of 33 months, the neuromodulator remained in place in 25 (55%) patients, two do whom switched it off, leaving 23 (51%) with a functioning neuromodulator. There was no statistically significant difference between the characteristics (including manometry, ultrasound and electrophysiology) of patients undergoing implantation (n = 32) or not (n = 13) and those with or without a functioning stimulator (n = 23: n = 13). In the 23 patients with a functioning stimulator the result was good in 12, satisfactory in five and poor in six. There was no statistically significant difference in the patient characteristics between those with a good result (n = 12) and the remainder (n = 32). Conclusion The findings suggest that investigation for FI does not facilitate patient selection for SNS and cannot be used to predict outcome.     

Electrical stimulation of the dorsal clitoral nerve reduces incontinence episodes in idiopathic faecal incontinent patients: a pilot study

Aim Faecal incontinence (FI) has a significant impact on quality of life. This study investigates whether stimulation of the dorsal genital nerve (DGN) improves FI symptoms. Method Ten female patients suffering from idiopathic FI (median age 60 years) were included in the study. Stimulation was applied twice daily for 3 weeks at the maximal tolerable stimulation amplitude (pulse width, 200 μs; pulse rate, 20 Hz). Patients kept a 3‐week bowel diary prior to stimulation, during stimulation and after the final stimulation. FI severity scores, FI Severity Visual‐Analogue Score (VAS), FI Quality of Life Score (FIQL), sphincter function and rectal volume tolerance were assessed at baseline, immediately after stimulation and 3 weeks after stimulation. Results Nine patients completed the study. The Wexner score (P = 0.027) and the St Mark’s score (P = 0.035) improved after stimulation in seven and six of the patients and improvement was maintained 3 weeks after stimulation (P = 0.048 and P = 0.049, respectively). The number of incontinent episodes was reduced in seven out of nine patients (P = 0.025). Improvement was maintained for 3 weeks after stimulation (P = 0.017). Subjective assessments of FI severity using the VAS score and the FIQl score did not improve during stimulation. Sphincter function and rectal volume tolerability were unaffected. Conclusion DGN stimulation reduced the number of FI episodes in most patients suffering from idiopathic FI. Sphincter function and rectal volume tolerability were not affected. DGN stimulation may represent a new treatment for idiopathic FI.     

Efficacy of vagus nerve stimulation for epilepsy by patient age, epilepsy duration, and seizure type

Medically refractory epilepsy is a morbid condition, and many patients are poor candidates for surgical resection because of multifocal seizure origin or eloquence near epileptic foci. Vagus nerve stimulation (VNS) was approved in 1997 by the US Food and Drug Administration as an adjunctive treatment of intractable epilepsy for individuals aged 12 years and more with partial epilepsy. Controversy persists regarding the efficacy of VNS for epilepsy and about which patient populations respond best to therapy. In this article, the authors retrospectively studied a patient outcome registry and report the largest, to their knowledge, analysis of VNS outcomes in epilepsy.     

Sacral spinal cord and root potentials evoked by the stimulation of the dorsal nerve of penis and cord conduction delay for the bulbocavernosus reflex

Segmental spinal cord and root potentials in response to stimulations of the dorsal nerve of penis, tibial nerve, and the sural nerve were epidurally recorded in normal subjects. EMG responses from the bulbocavernosus (BC) and the various leg muscles were also recorded in response to bipolar stimulations by the same epidural needle electrodes of the sacral cord and lumbosacral roots. The afferent conduction velocity from the penis to Th₁₂-L₁ intervertebral level was about 40 m/sec on the average, which is significantly slower than those obtained by the stimulation of the mixed and cutaneous nerves at the lower limb. The latency of the motor responses of the BC muscle from Th₁₂-L₁ spine levels were found comparatively longer than those of thigh muscles on maximal epidural stimulation in spite of the shorter distances to the BC muscle. The central conduction delay within the sacral cord of the bulbocavernosus reflex was calculated and found to be about 8.2 msec, while the central conduction time was about 1.1 msec for the Soleus-H-Reflex. These findings may suggest that there may be about 5–6 synapsis necessary for the first component of the bulbocavernosus reflex, though some faster oligosynaptic cord linkage may also exist.     

Predictive factors for successful sacral nerve stimulation in the treatment of faecal incontinence: a 10-year cohort analysis

Objective Sacral nerve stimulation (SNS) is an established treatment for faecal incontinence. We aimed to identify specific factors that could predict the outcome of temporary and permanent stimulation. Method A cohort analysis was performed to identify potential predictive factors in 81 patients who underwent temporary SNS at a single institution over a 10‐year period (June 1996 to June 2006). Data were obtained from prospectively collected patient symptom diaries and quality of life questionnaires, operation reports, anorectal physiological studies, endoanal ultrasound images and radiology of lead placement. Results Clinical outcome of temporary screening was not affected by patient gender, age, body mass index, severity or length of symptoms. The need for a repeated temporary procedure was associated with subsequent failure during screening (P = 0.008). A low threshold to obtain a motor response during temporary lead insertion was associated with improved outcome (P = 0.048). Evidence of anal sphincter trauma was associated with a greater risk of failure (P = 0.040). However, there was no difference in medium‐term outcome between patients with external anal sphincter (EAS) defects and patients with intact anal sphincter muscles. Conclusion Variables have been identified that help to predict the outcome of SNS. The presence of an EAS defect should not preclude treatment.     

Value of sacral nerve stimulation in the treatment of severe faecal incontinence: a comparison to the artificial bowel sphincter

Objective  Sacral nerve stimulation (SNS) is a recent treatment option in the management of severe faecal incontinence (FI) that offers promising results. The aim of this study was to compare SNS to artificial bowel sphincter (ABS) implanted patients to assess the rationale of this approach in achieving satisfying functional results and improved quality of life (QoL).
Method  Among 27 patients tested (December 2001 and April 2004), 15 patients were successfully managed with SNS. They were compared to 15 matched patients implanted with ABS in a previous period (control group). Assessment of continence level (Cleveland Clinic score), constipation score (Knowles, Eccersley, Scott Score) and QoL (Short-Form 36) were prospectively collected.
Results  Both groups were comparable for clinical parameters (age, gender, anal testing and aetiology of incontinence) and anal physiology. The mean postoperative continence score was significantly higher in the SNS group [9.4 (±3.3) vs 5.7 (±3.9), P  < 0.01]; however, the mean constipation score was higher in the ABS group (6.3 ± 6.3 vs 12.8 ± 5.7, P  < 0.01). The mean QoL score was similar in both groups. The mean follow-up after implantation was 15 (±9) months in the SNS group, and 43 (±33) months in the ABS group.
Conclusion  In this study, SNS offers satisfying results in terms of QoL, similar to that of ABS. Although it seems to be less effective in restoring continence level, symptoms of outlet obstruction are more frequent after ABS. This SNS approach should be proposed as a first-line treatment of FI in selected patients. ABS should remain an option that can improve function.