Altered sacral neural crest development in Pax3 spina bifida mutants underlies deficits of bladder innervation and function

Mouse models of Spina bifida (SB) have been instrumental for identifying genes, developmental processes, and environmental factors that influence neurulation and neural tube closure. Beyond the prominent neural tube defects, other aspects of the nervous system can be affected in SB with significant changes in essential bodily functions such as urination. SB patients frequently experience bladder dysfunction and SB fetuses exhibit reduced density of bladder nerves and smooth muscle although the developmental origins of these deficits have not been determined. The Pax3 Splotch-delayed (Pax3^Sp-d) mouse model of SB is one of a very few mouse SB models that survives to late stages of gestation. Through analysis of Pax3^Sp-d mutants we sought to define how altered bladder innervation in SB might arise by tracing sacral neural crest (NC) development, pelvic ganglia neuronal differentiation, and assessing bladder nerve fiber density. In Pax3^Sp-d/Sp-d fetal mice we observed delayed migration of Sox10+ NC-derived progenitors (NCPs), deficient pelvic ganglia neurogenesis, and reduced density of bladder wall innervation. We further combined NC-specific deletion of Pax3 with the constitutive Pax3^Sp-d allele in an effort to generate viable Pax3 mutants to examine later stages of bladder innervation and postnatal bladder function. Neural crest specific deletion of a Pax3 flox allele, using a Sox10-cre driver, in combination with a constitutive Pax3^Sp-d mutation produced postnatal viable offspring that exhibited altered bladder function as well as reduced bladder wall innervation and altered connectivity between accessory ganglia at the bladder neck. Combined, the results show that Pax3 plays critical roles within sacral NC that are essential for initiation of neurogenesis and differentiation of autonomic neurons within pelvic ganglia.

Sacral nerve stimulation allows for decreased antegrade continence enema use in children with severe constipation

BACKGROUND

Sacral nerve stimulation (SNS) can be beneficial for children with constipation, but no studies have focused on children with constipation severe enough to require antegrade continence enemas (ACEs). Our objective was to evaluate the efficacy of SNS in children with constipation treated with ACE.

METHODS

Using a prospective patient registry, we identified patients <21years old who were receiving ACE prior to SNS placement. We compared ACE/laxative usage, PedsQL Gastrointestinal Symptom Scale (GSS), Fecal Incontinence Quality of Life Scale (FIQL), Fecal Incontinence Severity Index (FISI), and Vancouver Dysfunctional Elimination Syndrome Score (DES) at baseline and progressive follow-up time intervals.

RESULTS

Twenty-two patients (55% male, median 12years) were included. Median ACE frequency decreased from 7 per week at baseline to 1 per week at 12months (p<0.0001). Ten children (45%) had their cecostomy/appendicostomy closed. Laxative use, GSS, FIQL, and DES did not change. FISI improved over the first 12months with statistical significance reached only at 6months (p=0.02). Six (27%) children experienced complications after SNS that required further surgery.

CONCLUSIONS

In children with severe constipation dependent on ACE, SNS led to a steady decrease in ACE usage with nearly half of patients receiving cecostomy/appendicostomy closure within 2years.

LEVEL OF EVIDENCE

IV.

Effects and indications of sacral surface therapeutic electrical stimulation in refractory urinary incontinence

Objective: To describe the effects and indications of sacral surface therapeutic electrical stimulation (SS-TES) for refractory urinary incontinence.

Design: Evaluation before and after therapy.

Setting: On clinical site and at nursing home.

Subjects: Seven neurogenic bladder, five unstable bladder and six nocturia cases were investigated. Twelve were outpatients and six were residents.

Interventions: Surface electrodes were placed at the posterior sacral foramens of S2 and S4. Stimulation conditions were duration 0.3 ms, frequency 20 Hz and maximum intensity. The stimulation was continued for 15 min twice daily for over one month.

Main outcome measures: Therapeutic effects were evaluated on the basis of voiding charts as subjective findings and urodynamic study as objective findings before and after therapy.

Results: Subjective findings showed incontinence frequency significantly decreased from 2.39±1.4 times/day before therapy to 1.39±2.0 times/day after therapy (p≤0.01); 55.5% of patients were improved or greatly improved. Objective findings showed that maximum vesical capacity (MVC) significantly increased from 208.29±94.5 ml before therapy to 282.19±66.8 ml (p≤0.001). Uninhibited contraction significantly decreased from 40.4±31.4 cmH2O before therapy to 25.79±23.9 cmH2O (p≤0.01); 44% of patients were improved or greatly improved. This therapy was effective in particular for cases whose MVC was small before applying SS-TES.

Conclusion: SS-TES was effective in some patients with refractory urinary incontinence.

Effects of sacral nerve stimulation on postpartum urinary retention-related changes in rat bladder

OBJECTIVE

To examine the effect of sacral nerve stimulation (SNS) on the urodynamic function and molecular structure of bladders in rats following acute urinary retention (AUR) after parturition.

MATERIAL AND METHODS

Thirty primiparous rats were divided into three groups: postpartum, postpartum+AUR, and postpartum+AUR+SNS. AUR was achieved by clamping the distal urethra of a rat for 60 minutes. The postpartum+AUR+SNS group received electrical stimulation 60 minutes daily for 3 days after AUR. In addition to cystometric studies and external urethral sphincter electromyography, the expression of caveolins and nerve growth factor (NGF) and caveolae number in bladder muscle were analyzed.

RESULTS

The postpartum+AUR group has significantly greater residual volume than the postpartum group, but the residual volume decreased significantly after SNS treatment. The postpartum+AUR group had significantly lower peak voiding pressure, a longer bursting period and lower amplitude of electromyograms of external urethral sphincter activity than the postpartum and postpartum+AUR+SNS groups. The postpartum+AUR rats had higher NGF expression, lower caveolin-1 expression, and fewer caveolae in bladder muscle compared with the postpartum rats. Conversely, the caveolin-1 expression and caveolae number increased, and the NGF expression decreased after SNS treatment.

CONCLUSION

Bladder dysfunction after parturition in a rat model caused by AUR may be restored to the non-AUR structural and functional level after SNS treatment.

A modified needle-inside-needle technique for the ganglion impar block

PURPOSE

The ganglion impar is the fused terminus of the paired sympathetic chain located at the level of the sacrococcygeal junction. It has been blocked using a bent and a curved spinal needle via the anococcygeal ligament. It has also been approached through the sacrococcygeal disc using a straight spinal needle. We describe a needle-inside-needle modification of the latter approach.Technical features: A 22-gauge (G), 1(1/2)-inch (38 mm) needle is introduced through the sacrococcygeal ligament under fluoroscopy via the sacrococcygeal disc. A 25-G, 2-inch (50 mm) needle is introduced through the 22-G needle. Placement is confirmed with injection of iopamidol 300, 0.2 mL in the retroperitoneal space with the comma sign.

CONCLUSIONS

The bent and curved needle techniques are associated with significant discomfort, tissue trauma and risk of rectal perforation due to difficulty in obtaining a midline needle tip position. The straight spinal needle approach minimizes these problems, however there is increased risk of discitis and a longer spinal needle may help also raise incidence of needle breakage. The needle-inside-needle technique may reduce these risks.

Similarities and differences in cervical and thoracolumbar multisegmental motor responses and the combined use for testing spinal circuitries

STUDY DESIGN

Experimental study.

OBJECTIVE

To determine similarities and differences of C7 and T11-12 multisegmental motor responses (MMR) studies for the upper limbs (UL) and lower limbs (LL).

SETTINGS

Neuroscience Lab, TWU (School of Physical Therapy, TX, USA).

METHODS

C7 and T11-12 percutaneous electrical stimulations were applied while recording muscle action potentials from ULs and LLs.

RESULTS

The procedure of cervical MMR (CMMR) was easier in application than thoracolumbar MMR (TMMR), requiring less current intensities but cause more "jolts" in the trapezius/shoulder complex, due to close proximity of the stimulation electrodes. CMMR evoked large amplitude motor responses in the millivolts range in (UL) muscles, but smaller amplitude signal in (LL) muscles (in microvolts). TMMR evoked large amplitude motor responses in both UL and LL (in millivolts). The MMR amplitude was generally larger in the UL as compared to the LL, in the distal limb muscles more than in the proximal limb muscles. CMMR and TMMR for the UL were comparable in amplitude, latencies and action potential shapes. Signal latencies were longer for distal limb muscles as compared to proximal limb muscles and were slightly longer for LL as compared to UL muscles. MMR signals were either biphasic or triphasic in shape.

CONCLUSION

CMMR and TMMR have similarities and differences in the methods and recording signal that must be considered during its clinical applications. Comparing the signal of the UL muscles with CMMR and TMMR could be a useful test for the integrity of the ascending and descending spinal pathways in patients with spinal cord injuries and diseases.

[Effect of the anterior aspect of sacral nerve root tunnel on iliosacral screw placement on the standard lateral image of sacrum]

OBJECTIVE

To introduce the location and course of S1, S2 sacral nerve root tunnel and to clarify the significance of the anterior aspect of sacral nerve root tunnel on placement of iliosacral screw on the standard lateral sacral view.

METHODS

Firstly the data of 2.0 mm slice pelvic axial CT images were imported into Mimics 10.0, and the sacrum, innominate bones, and sacral nerve root tunnels were reconstructed into 3D views respectively, which were rotated to the standard lateral sacral views, pelvic outlet and inlet views. Then the location and course of the S1, S2 sacral nerve root tunnel on each view were observed.

RESULTS

The sacral nerve root tunnel started from the cranial end and anterior aspect of the vertebral canal of the same segment and ended up to the anterior sacral foramen with a direction from cranial-posterior-medial to caudal-anterior-lateral. The tunnel had a lower density than the iliac cortex and greater sciatic notch on the pelvic X-rays,especially on the standard sacral lateral view, on which it showed up as a disrupted are line and required more careful recognition.

CONCLUSION

It can prevent the iliosacral screw from penetrating the sacral nerve root tunnel and vertebral canal when recognizing the anterior aspect of sacral nerve root tunnel and choosing it as the caudal-posterior boundary of the "safe zone" on the standard lateral sacral view.

The anatomy of the sacrococcygeal cornual region and its clinical relevance

There has been no systematic study of the anatomy of the region between the sacral and coccygeal cornua. Reference texts describe an intercornual ligament connecting these structures. The aim of this study was to investigate the anatomy of this region, which may be relevant to unexplained cases of coccygeal pain (coccydynia) and local nerve blocks. The bony anatomy of the sacrococcygeal (SC) cornual region was analyzed in 33 CT scans obtained from supine adults of mostly European origin with no known SC pathology, 7 μCT scans of cadaver SC specimens, and 105 Asian Indian adult skeletons. A further five cadaver SC specimens were examined histologically. SC cornual fusion was seen in 45% of CT/μCT scans (mean age 67 years, 20 males) and in 20% of adult skeletons (78 males); there was no association with age or sex. In the absence of SC fusion, the mean intersacrococcygeal cornual gap was 7.1 ± 2.4 mm; this was bridged by an intercornual ligament composed of parallel vertical collagen fibers reinforced by elastin fibers on its anterior surface. Small nerve branches were observed adjacent to the ventral aspect of the intercornual ligament and, in one case, traversing the ligament. Ipsilateral sacral and coccygeal cornua are therefore normally bridged by an intercornual ligament that is probably innervated. The cornua are fused on one or both sides in 20-45% of adults. These findings may have implications for some cases of coccydynia and for anesthetists performing local nerve blocks.

[Dynamics of structural changes in the dorsal roots of spinal nerves in growing dogs]

Dorsal roots of spinal nerves (S1 segment) were studied in 9 growing mongrel dogs aged 2, 5 and 10 months using morphologic and morphomertric the methods. Longitudinal paraffin sections, impregnated with silver nitrate, and semithin transverse sections, stained with methylene blue-basic fuchsin, were used. The general regularities of structural organization, as well as the patterns of nerve fiber arrangement in the studied age periods have been determined. In the process of growth, the thickening of the dorsal roots was found (which was most pronounced until 5 months together with the increase of the diameter and the changes in the proportions of small, medium and large myelinated nerve fibers, the decrease of their number per unit section area.

Individual patient data meta-analysis of randomized evidence to assess the effectiveness of laparoscopic uterosacral nerve ablation in chronic pelvic pain

BACKGROUND

There have been conflicting results in randomized trials of the effects of laparoscopic uterosacral nerve ablation (LUNA) in chronic pelvic pain. Our objective was to perform a meta-analysis using individual patient data (IPD) to provide the most comprehensive and reliable assessment of the effectiveness of LUNA.

METHODS

Electronic searches were conducted in the Medline, Embase, PsycInfo and Cochrane Library databases from database inception to August 2009. The reference lists of known relevant papers were searched for any further articles. Randomized trials comparing LUNA with no additional intervention were selected and authors contacted for IPD. Raw data were available from 862 women randomized into five trials. Pain scores were calibrated to a 10-point scale and were analysed using a multilevel model allowing for repeated measures.

RESULTS

There was no significant difference between LUNA and No LUNA for the worst pain recorded over a 12 month time period (mean difference 0.25 points in favour of No LUNA on a 0-10 point scale, 95% confidence interval: -0.08 to 0.58; P = 0.1).

CONCLUSIONS

LUNA does not result in improved chronic pelvic pain.

[Diagnostic image (376). A man with a tumour in the anal seam]

A 50-year-old man presented with a sacral tumour due to a sacrococcygeal chordoma.

Intraoperative mapping of sacral nervous system (S2-4)

Electrophysiological mapping of the sacral nervous system was used during operations on 80 patients with conus and cauda equina lesions. At surgery, under controlled muscle relaxation, the sacral neural elements (S2-4) were mapped using direct mono-polar stimulation and recording of compound muscle action potentials (CMAPs) from the external anal sphincter (EAS). Responses were obtained in 86.25% (69/80) of the patients. In 33 (82.5%) out of 40 patients with preoperative deficits involving the S2-4 segments, CMAPs could be elicited. Identification of nerve roots was useful in dissection of lipomyelomeningocoeles, tumour excisions and untethering of filum terminale. In three patients, stimulation of the filum terminale elicited motor responses and, hence, it was not sectioned. Intraoperative mapping of the S2-4 nerve roots under controlled muscle relaxation is feasible in a majority of patients, including those with deficits involving S2-4. This method was useful in sparing viable nerve roots during surgery in conus and cauda equina regions, and identification of 'functional' filum terminale.

Innervation of the levator ani muscles: description of the nerve branches to the pubococcygeus, iliococcygeus, and puborectalis muscles

We described the innervation of the levator ani muscles (LAM) in human female cadavers. Detailed pelvic dissections of the pubococcygeus (PCM), iliococcygeus (ICM), and puborectalis muscles (PRM) were performed on 17 formaldehyde-fixed cadavers. The pudendal nerve and the sacral nerves entering the pelvis were traced thoroughly, and nerve branches innervating the LAM were documented. Histological analysis of nerve branches entering the LAM confirmed myelinated nerve tissue. LAM were innervated by the pudendal nerve branches, perineal nerve, and inferior rectal nerve (IRN) in 15 (88.2%) and 6 (35.3%) cadavers, respectively, and by the direct sacral nerves S3 and/or S4 in 12 cadavers (70.6%). A variant IRN, independent of the pudendal nerve, was found to innervate the LAM in seven (41.2%) cadavers. The PCM and the PRM were both primarily innervated by the pudendal nerve branches in 13 cadavers (76.5%) each. The ICM was primarily innervated by the direct sacral nerves S3 and/or S4 in 11 cadavers (64.7%).

Neurophysiologic changes after preganglionic and postganglionic nerve-root constriction: an experimental study in the rat

STUDY DESIGN

We investigated changes in spinal somatosensory-evoked potential (SSEP) and nerve action potential (NAP), correlated behavior, and associated pathologic observation in experimental radiculopathy.

OBJECTIVES

To create a rat model of sacrococcygeal radiculopathy for determining the validity of SSEP and NAP.

SUMMARY OF BACKGROUND DATA

We examined the diagnostic sensitivity and value of electrophysiologic tests for evaluating lumbosacral root disease conflict. An appropriate animal model can help verify the value of these tests.

METHODS

Preganglionic lesion group rats were given 2 loose ligatures around the cauda equina at the sacrum, and postganglionic lesion group rats were given 2 loose ligatures on the conjunction of the sacrococcygeal nerve roots and the caudalis nerve after they had received a laminectomy. Control group rats received a sham operation. SSEPs and NAPs were recorded preligature and postligature, and 3 times after surgery. These electrophysiologic observations were compared and correlated with tail-flick reflex and histology.

RESULTS

All experimental group rats developed thermal hyperalgesia on day 14, as indicated by a significant reduction in TFL (tail-flick latency), which continued for 3 months. Amplitude decreased significantly and latency increased significantly in all SSEP recordings immediately after the operation; these changes persisted for 3 months. There were no significant differences between the experimental groups, but there were significant differences between the control and experimental groups. NAP amplitude and latency from the caudalis nerves did not change in any group in the first 2 postoperative weeks. From the second postoperative week until the 3-month follow-up, amplitude was significantly decreased and latency prolonged in the postganglionic group but unchanged in the others.

CONCLUSIONS

Both SSEP and NAP are useful for evaluating electrophysiologic changes after various radiculopathies. The data also suggest that the conductivity of the peripheral nerve (NAP) was affected by the postganglionic compression of the corresponding nerve root, but not by the preganglionic lesion.

Sacral neuromodulation in the treatment of severe anal incontinence

INTRODUCTION

Sacral neuromodulation is a recognized therapeutic option in severe anal incontinence from neurogenic origins, when medical treatment has failed.

METHODS

We report the results of this procedure applied in 40 consecutive patients operated on by a single surgeon from August 2001 to June 2004. Mean duration of incontinence was 5 years. There were 33 women and 7 men of mean age 59 (range 29-89). All patients had had medical treatment, 26 had had physiotherapy and 9 had been previously operated on for that problem. Neuromodulation consisted in a temporary electrical stimulation test followed by implantation of a stimulator in case of efficacy.

RESULTS

Twenty nine patients had a positive test and were implanted. Ten had a negative test and one is waiting for implantation. From the 29 patients, 23 had uneventful postoperative course. Incontinence score varied from 17 before neuromodulation to 6 after in the 24 patients who were improved. Mean resting pressure, mean maximum squeeze pressure and mean duration of squeeze pressure did not change from pre to postoperative period.

CONCLUSION

Sacral neuromodulation is a safe and efficacious procedure in properly selected anal incontinent patients. However, we observed no correlation between clinical and manometric data.

Which patients need referral for anal sphincter electromyography?

Needle electromyography (EMG) of lower sacral myotomes is useful in certain patients with urinary, bowel, or sexual dysfunction. The aim of the study was to identify the clinical profile of patients who require such testing. Medical records were retrospectively reviewed, and findings evaluated using bivariate and multivariate statistics. A neuropathic condition affecting the lower sacral segments was diagnosed by quantitative concentric needle EMG of the external anal sphincter (EAS) muscle. Neuropathic changes in the EAS were found in 85 (44%) of 193 patients studied. On ordinal logistic regression analysis, bladder-emptying difficulties and perineal sensory loss were significantly related to the presence of a neuropathic EMG. No guidelines for referral for anal sphincter EMG could be defined that would include all patients with neuropathic abnormalities in the lower sacral segments. However, patients with bladder-emptying difficulties and perineal sensory loss seem to be the most suitable candidates for testing.

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.

When is Onuf's nucleus involved in multiple system atrophy? A sphincter electromyography study

BACKGROUND

External anal sphincter (EAS) electromyography (EMG) abnormalities can distinguish multiple system atrophy (MSA) from Parkinson's disease in the first five years after disease onset. However, the prevalence of the abnormalities in the early stages of MSA is unknown.

OBJECTIVES

To present EAS-EMG data in the various stages of MSA.

METHODS

84 patients with "probable" MSA were recruited (42 men, 42 women; mean age 62 years (range 47 to 78); mean disease duration 3.2 years (0.5 to 8.0; <1 year in 25%); 50 cerebellar form (MSA-C), 34 parkinsonian form (MSA-P)). EAS motor unit potential (MUP) analysis and EMG cystometry were carried out in all patients.

RESULTS

The overall prevalence of neurogenic change of the EAS MUP was 62%-52% in the first year after disease onset, increasing to 83% by the fifth year (p<0.05); it also increased with severity of gait disturbance (p<0.05), storage and voiding disorders, and detrusor sphincter dyssynergy (NS). The neurogenic change was not correlated with sex, age, MSA-P/C, postural hypotension, constipation, erectile dysfunction in men, underactive or acontractile detrusor, or detrusor overactivity. In 17 incontinent patients without detrusor overactivity or low compliance, urinary incontinence was more severe in those with neurogenic change than in those without (p<0.05).

CONCLUSIONS

Involvement of Onuf's nucleus in MSA is time dependent. Before the fifth year of illness, the prevalence of neurogenic change does not seem to be high, so a negative result cannot exclude the diagnosis of MSA.

Surgical interruption of pelvic nerve pathways for primary and secondary dysmenorrhoea

BACKGROUND

Dysmenorrhoea is the occurrence of painful menstrual cramps of uterine origin and is a very common gynaecological complaint with negative effect on a sufferer's quality of life. Medical therapy for dysmenorrhoea includes oral contraceptive pills (OCP) and nonsteroidal anti-inflammatory drugs (NSAIDs) which both act by suppressing prostaglandin levels. While these treatments are very successful there is still a 20 to 25% failure rate and surgery has been an option for such cases. Uterine nerve ablation (UNA) and presacral neurectomy (PSN) are two surgical treatments that have become increasingly utilised in recent years due to advances in laparoscopic procedures. These procedures both interrupt the majority of the cervical sensory pain nerve fibres. Observational studies have supported the use of these procedures for primary dysmenorrhoea. However, both operations only partially interrupt the cervical sensory nerve fibres in the pelvic area and, therefore, this type of surgery may not always benefit women with dysmenorrhoea.

OBJECTIVES

To assess the effectiveness of surgical interruption of pelvic nerve pathways as treatment for primary and secondary dysmenorrhoea, and to determine the most effective surgical treatment.

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders and Subfertility Group Trials Register (searched 9 June 2004), CENTRAL (The Cochrane Library Issue 2, 2004), MEDLINE (1966 to Nov 2003), EMBASE (1980 to Nov 2003), and CINAHL (1982 to Oct 2003). Attempts were also made to identify trials from the metaRegister of Controlled Trials and the citation lists of review articles and included trials. In most cases the first or corresponding author of each included trial was contacted for additional information.

SELECTION CRITERIA

The inclusion criteria were randomised comparisons of surgical techniques of interruption of the pelvic nerve pathways (using both open and laparoscopic procedures) for the treatment of primary and secondary dysmenorrhoea. The main outcome measures were pain relief and adverse effects.

DATA COLLECTION AND ANALYSIS

Eleven randomised controlled trials (RCTs) were identified that initially appeared to fulfil the inclusion criteria for this review. Two trials were subsequently excluded (Garcia Leon 2003; Sutton 1991). Of the remaining nine trials, eight were included in the meta-analysis. The results of one trial were included in the text of the review for discussion because the data were not available in a form that allowed them to be combined in the meta-analysis. Five trials investigated laparoscopic uterine nerve ablation (LUNA), two trials laparoscopic presacral neurectomy (LPSN) and two open presacral neurectomy (PSN).

MAIN RESULTS

For the treatment of primary dysmenorrhoea there was some evidence of the effectiveness of laparoscopic uterine nerve ablation (LUNA) when compared to a control or no treatment. The comparison between LUNA and laparoscopic presacral neurectomy (LPSN) for primary dysmenorrhoea showed no significant difference in pain relief in the short term; however, long-term LPSN was shown to be significantly more effective than LUNA. For the treatment of secondary dysmenorrhoea six identified RCTs addressed endometriosis and one included women with uterine myomas. The treatment of LUNA combined with surgical treatment of endometrial implants versus surgical treatment of endometriosis alone showed that the addition of LUNA did not aid pain relief. For PSN combined with endometriosis treatment versus endometriosis treatment alone there was an overall difference in pain relief although the data suggests this may be specific to laparoscopy and for midline abdominal pain only. Adverse events were significantly more common for presacral neurectomy; however, the majority were complications such as constipation, which may spontaneously improve.

AUTHORS' CONCLUSIONS

There is insufficient evidence to recommend the use of nerve interruption in the management of dysmenorrhoea, regardless of cause. Future methodologically sound and sufficiently powered RCTs should be undertaken.

Sacral nerve stimulation for faecal incontinence following a rectosigmoid resection for colorectal cancer

INTRODUCTION

Following recto-sigmoid resection some patients may become faecally incontinent and remain so despite conservative treatment. This multicentre prospective study assessed the use of sacral nerve stimulation (SNS) in this group.

METHODS

All patients had more than or equal to 4 days of faecal incontinence for solid or liquid stools over a 21-day period following recto-sigmoid resection for colorectal carcinoma. The operation had to have been deemed curative. They had to have failed pharmacological and biofeedback treatment.

RESULTS

Three male patients met these criteria. One had had a colo-anal and two a colo-rectal anastomosis for rectal carcinoma. All patients had intact internal and external anal sphincters. Two patients had a successful temporary stimulation period and proceeded to permanent implantation. Pre-operative symptom duration was 1 year in the permanently implanted patients. They were followed up for 12 months. SNS improved the number of faecally incontinent episodes in both patients. Ability to defer was improved in both patients from 0--5 min to 5--15 min. The faecal incontinence-specific ASCRS quality of life assessment improved in all four subcategories.

CONCLUSION

This study demonstrates that SNS may be effective in the treatment of patients with faecal incontinence following recto-sigmoid resection if conservative treatment has failed.

New tined lead electrode in sacral neuromodulation: experience from a multicentre European study

The use of a new tined lead electrode for sacral neuromodulation (SNS) was evaluated in a European study including 127 patients with chronic voiding dysfunction. The tined lead can be implanted during the first stage of the SNS procedure, which makes a longer test period possible before implanting the pulse generator in a second stage. Implantation of the tined lead was performed under local anaesthesia in 89% of patients. Screening lasted on average 30 days. Screening with the tined lead was considered successful by the physicians in 77% of patients (n=72). In 74% of first stage patients (n=70), at least 50% improvement in the main symptoms versus baseline was obtained. This was sustained for up to 6 weeks. All of these patients received the pulse generator in a second stage. The outcome of this study supports the use of the tined lead electrode as a screening tool in SNS therapy.

[Sacral nerve stimulation in the treatment of faecal incontinence]

The sacral nerve stimulation is a new promising procedure for faecal incontinence in patients in whom conservative treatments have failed. In contrast to more invasive restorative surgeries (e.g. dynamic graciloplasty or artificial sphincter), sacral nerve stimulation can be tested and performed in outpatient under local anaesthesia. From May 2001 to April 2004, 25 consecutive patients with faecal incontinence underwent percutaneous test-stimulation during 10 to 14 days. The test was positive in 16 of them (64%) in whom a permanent implantation of an internal pulse generator was performed. During the follow up of this group a significant reduction of the number of incontinence episodes and a considerable improvement of quality of life was demonstrated. Complete investigations and restrictive patient selection, as well as a carefully follow up are recommended for the success in sacral nerve stimulation therapy.

Potentiation, activation and blockade of GABAA receptors by etomidate in the rat sacral dorsal commissural neurons

Etomidate (ET), an imidazole general anesthetic, has been medically widely used. Recent evidence suggests that the inhibitory neurotransmitter GABA receptor may be one of the important molecular target(s) of general anesthetics. Up to date, little attention has been directed toward the sacral dorsal commissural nucleus (SDCN), which serves as a relay of sensory information from the pelvic viscera in the spinal cord. Therefore, the effect of ET on GABA(A) receptor function in neurons acutely dissociated from the SDCN was investigated using the nystatin-perforated patch-recording configuration under voltage-clamp conditions. At a holding potential of -40 mV, ET (above 10 microM) induced an inward ET-activated current (I(ET)) with the EC(50) value of 33 +/- 3 microM, which was reversibly blocked by bicuculline and picrotoxin. The reversal potential of I(ET) was close to the Cl(-) equilibrium potential. ET also displayed a biphasic modulatory effect on GABA responses. At lower concentrations (0.1-100 microM), ET reversibly potentiated GABA (1 microM)-activated Cl(-) currents in a bell-shaped manner, with the maximal facilitative effect at 10 microM, whereas at concentrations >100 microM, the peak of the ET-induced current was suppressed in the absence or presence of GABA (1 microM). These results suggest that in SDCN, in addition to the potentiation of GABA(A) receptor-mediated responses at low concentrations and the direct activation of GABA(A) receptors at moderate concentrations as expected, ET produced a fast blocking action at high concentrations. The general anesthetic-induced effects in SDCN, at least the potentiation of GABA responses, may significantly contribute to anesthesia of pelvic viscera during the general anesthesia.

Medikament�se Therapie der Belastungsinkontinenz

Urinary continence and voiding are complex physiological processes and require the coordination of all three efferent areas of the nervous system (parasympathetic, sympathetic, somatic). The pudendal nerve contains efferent as well as afferent fibers, the former ones having their origin in Onuf's nucleus. A number of studies see a link in the central modulation of lower urinary tract activity through 5-HT and NE receptor agonists as well as antagonists. Previous information about the modulation of the lower urinary tract in humans has been obtained from animal experiments. Duloxetin, a combined serotonin/norepinephrine reuptake inhibitor may prove to be a new therapeutic agent for stress urinary incontinence. Duloxetin appears to act at the presynaptic neuron of Onuf's nucleus. A phase II and three phase III studies have shown significant and clinically relevant improvement in several parameters in comparison to placebo control. The most frequent adverse event observed was nausea.

Duloxetine: mechanism of action at the lower urinary tract and Onuf?s nucleus

Urinary incontinence is the inability to willingly control bladder voiding. Stress urinary incontinence (SUI) is the most frequently occurring type of incontinence in women. No widely accepted or approved drug therapy is yet available for the treatment of stress urinary incontinence. Numerous studies have implicated the neurotransmitters, serotonin and norepinephrine in the central neural control of the lower urinary tract function. The pudendal somatic motor nucleus of the spinal cord is densely innervated by 5HT and NE terminals. Pharmacological studies confirm central modulation of the lower urinary tract activity by 5HT and NE receptor agonists and antagonists. Duloxetine is a combined serotonin/norepinephrine reuptake inhibitor currently under clinical investigation for the treatment of women with stress urinary incontinence. Duloxetine exerts balanced in vivo reuptake inhibition of 5HT and NE and exhibits no appreciable binding affinity for receptors of neurotransmitters. The action of duloxetine in the treatment of stress urinary incontinence is associated with reuptake inhibition of serotonin and norepinephrine at the presynaptic neuron in Onuf's nucleus of the sacral spinal cord. In cats, whose bladder had initially been irritated with acetic acid, a dose-dependent improvement of the bladder capacity (5-fold) and periurethral EMG activity (8-fold) of the striated sphincter muscles was found. In a double blind, randomized, placebo-controlled, clinical trial in women with stress urinary incontinence, there was a significant reduction in urinary incontinence episodes under duloxetine treatment. In summary, the pharmacological effect of duloxetine to increase the activity of the striated urethral sphincter together with clinical results indicate that duloxetine has an interesting therapeutic potential in patients with stress urinary incontinence.

Mechanisms of H+ modulation of glycinergic response in rat sacral dorsal commissural neurons

Many ionotropic receptors are modulated by extracellular H+. So far, few studies have directly addressed the role of such modulation at synapses. In the present study, we investigated the effects of changes in extracellular pH on glycinergic miniature inhibitory postsynaptic currents (mIPSCs) as well as glycine-evoked currents (IGly) in mechanically dissociated spinal neurons with native synaptic boutons preserved. H+ modulated both the mIPSCs and IGly biphasically, although it activated an amiloride-sensitive inward current by itself. Decreasing extracellular pH reversibly inhibited the amplitude of the mIPSCs and IGly, while increasing external pH reversibly potentiated these parameters. Blockade of acid-sensing ion channels (ASICs) with amiloride, the selective antagonist of ASICs, or decreasing intracellular pH did not alter the modulatory effect of H+ on either mIPSCs or IGly. H+ shifted the EC50 of the glycine concentration-response curve from 49.3 +/- 5.7 microM at external pH 7.4 to 131.5 +/- 8.1 microM at pH 5.5, without altering the Cl- selectivity of the glycine receptor (GlyR), the Hill coefficient and the maximal IGly, suggesting a competitive inhibition of IGly by H+. Both Zn2+ and H+ inhibited IGly. However, H+ induced no further inhibition of IGly in the presence of a saturating concentration of Zn2+. In addition, H+ significantly affected the kinetics of glycinergic mIPSCs and IGly. It is proposed that H+ and/or Zn2+ compete with glycine binding and inhibit the amplitude of glycinergic mIPSCs and IGly. Moreover, binding of H+ induces a global conformational change in GlyR, which closes the GlyR Cl- channel and results in the acceleration of the seeming desensitization of IGly as well as speeding up the decay time constant of glycinergic mIPSCs. However, the deprotonation rate is faster than the unbinding rate of glycine from the GlyR, leading to reactivation of the undesensitized GlyR after washout of agonist and the appearance of a rebound IGly. H+ also modulated the glycine cotransmitter, GABA-activated current (IGABA). Taken together, the results support a "conformational coupling" model for H+ modulation of the GlyR and suggest that H+ may act as a novel modulator for inhibitory neurotransmission in the mammalian spinal cord.

Update on sacral neuromodulation: Indications and outcomes

Tanagho and Schmidt first introduced sacral nerve neuromodulation in 1981. Since then, it has become increasingly popular and the indications for this procedure are growing. The purpose of this article is to discuss the established indications for sacral nerve stimulation (SNS). The outcomes of the most recent studies and trials dealing with SNS are presented. An overview of the most recent techniques used for neuromodulation is detailed.

Sacral neuromodulation in an older, urge-incontinent population

OBJECTIVE

The success of sacral neuromodulation in the treatment of urge incontinence has been reported in young populations. Herein we report the success in an older, urge-incontinent population.

STUDY DESIGN

A cohort of 25 patients older than 55 years who had failed conventional therapy for the treatment of urge incontinence underwent percutaneous S3 sacral nerve test stimulation. Patients were considered candidates for permanent implantation if they were cured or had a greater than 50% improvement in incontinent episodes. Responders were implanted and completed a questionnaire, bladder diary, and disease-specific quality-of-life questionnaire.

RESULTS

Twelve of the 25 patients (48%) responded to the test stimulation. The average follow-up after permanent implantation was 7.8 months. All patients obtained a >50% reduction in their incontinent episodes; 2 patients achieved total dryness.

CONCLUSION

Our small cohort suggests that older urge-incontinent patients have improvement with sacral neuromodulation but cure rates may be lower than with a younger population.

Sacrococcygeal ganglioneuroma

Ganglioneuromas are benign slow-growing masses that can be treated with complete surgical extirpation without any adjuvant therapy. Such lesions involving the sacrococcygeal region are exceedingly rare. The authors present the case of a 70-year-old woman with a sacrococcygeal ganglioneuroma treated by total en bloc resection. This patient also had a previous coccygeal fracture. To the authors' knowledge, there are no other reports of ganglioneuroma in association with a history of trauma.

[Temporary sacral and tibial neuromodulation in treating patients with overactive urinary bladder]

The effects of temporary sacral (S3) stimulation and posterior tibial nerve stimulation were studied in patients with the overactive urinary bladder. Unilateral temporal (10 days) electrical stimulation of the S3 sacral spinal nerve (32 patients) and posterior tibial nerve stimulation (18 patients) were used to treat this abnormality. There was a decrease in the average frequency of voiding, in the number of leakage episodes and used pads per day after both stimulations. An over 50% symptomatic improvement was achieved in 19 of the 32 patients and after temporary sacral (S3) stimulation and in 14 of the patients following posterior tibial nerve stimulation. Neuromodulation is an effective treatment in patients with the overactive bladder.

New, simple, ultrasound-guided infiltration of the pudendal nerve: ultrasonographic technique

PURPOSE

Anesthetic infiltration of the pudendal nerve at the ischial spine can relieve perineal pain in cases of compression or distention. The aim of our study was to look for a real-time, visually controlled infiltration technique using ultrasound.

METHODS

Fifty-three volunteers were examined in a prone position using a 3.5-MHz curved-array probe in color-coded Doppler mode. The deep gluteal region was scanned in two perpendicular planes, longitudinal and transverse to the internal pudendal artery.

RESULTS

On the transverse planes the ischial spine, the sacrospinous ligament, and the internal pudendal artery were depicted in all but two cases. In 47.2 percent of the cases one trunk of the pudendal nerve was detected directly. Nerves consisting of more than one trunk were not found. The thickness of the nerve ranged between 3.5 and 7 mm.

CONCLUSIONS

In almost one-half of the cases a direct ultrasound-guided infiltration of the pudendal nerve is possible. In the remaining cases the nerve can be detected and blocked indirectly, using the ischial spine or the internal pudendal artery as a landmark.

New, simple, ultrasound-guided infiltration of the pudendal nerve: topographic basics

PURPOSE

We report the topographic relationship of the pudendal nerve to the accompanying pudendal vessels and the ischial spine and provide the basics for an ultrasonographic depiction of these structures.

METHODS

Twenty-nine female and 29 male adult human cadavers were positioned prone to expose the deep gluteal region. In 58 left and 58 right pelves the course of the pudendal nerve and vessels at the ischial spine were evaluated and analyzed statistically (n = 116).

RESULTS

Multitrunked pudendal nerves were found in 40.5 percent with a left-vs.-right ratio of 1:1.5. The diameters of the single-trunked nerves ranged from 1.3 to 6.8 (mean 3.6 +/- 1.1) mm. In 75.9 percent the pudendal nerve was found medial to the accompanying internal pudendal artery. The distance to the artery ranged from 17.2 mm medial to 8 mm lateral (mean, 3.4 mm medial +/- 4.1 mm). The distance to the tip of the ischial spine ranged from 13.4 mm medial to 7.4 mm lateral (mean, 2.1 mm medial +/- 3.7 mm).

CONCLUSIONS

The knowledge of the close spatial relationship between the pudendal nerve and the internal pudendal artery is important for any infiltration technique and even surgical release. It demands real-time, visually controlled infiltration techniques, such as with ultrasound.

Interventional neurophysiology of the sacral nervous system

Clinical neurophysiological tests have been introduced for the sacral neuromuscular system to aid with diagnosis of neurogenic conditions involving the lower urinary tract, anorectal and sexual dysfunction. The tests have, however, the potential to be of value in different interventions outside of the neurophysiological laboratory. EMG monitoring can be used for exact application of botulinum toxin by the relatively non-invasive transcutaneous approach in treatment of male detrusor sphincter dyssynergia. Checking for compound muscle action potentials of the external anal sphincter is proposed as the best method for exact placement of wire electrodes close to the 3rd sacral roots in treating lower urinary tract dysfunction by 'neuromodulation'. Presently the most established use of clinical neurophysiological techniques--outside the laboratory--as related to the sacral neuromuscular system is in the operating theatre. These tests have been introduced to identify relevant structures, for instance pudendal afferents within dorsal sacral roots, which should be spared during rhizotomy procedures for treatment of spasticity. Modified techniques are used intraoperatively to monitor the integrity of the lower sacral reflex arc (the bulbocavernosus reflex) or the lower sacral afferents throughout the spinal cord (pudendal SEP). Clinical neurophysiological tests are expected to become established in several interventions involving the sacral neuromuscular system.

The pain cycle: implications for the diagnosis and treatment of pelvic pain syndromes

The aim of the study was to report our results of sacral nerve stimulation in patients with pelvic pain after failed conservative treatment. From 1992 to August 1998 we treated 111 patients (40 males, 71 females, ages 46 +/- 16 years) with chronic pelvic pain. All patients with causal treatment were excluded from this study. Pelvic floor training, transcutaneous electrical nerve stimulation (TENS) and intrarectal or intravaginal electrostimulation were applied and sacral nerve stimulation was used for therapy-resistant pain. The outcome of conservative treatment and sacral nerve stimulation (VAS <3/10; >50% pain relief) was related to symptoms of voiding dysfunction and dyschezia, and urodynamic proof of dysfunctional voiding, not to the pain localization or treatment modality. Outcome was inversely related to neuropathic pain. When conservative treatment failed, a test stimulation of the S3 root was effective in 16/26 patients, and 11 patients were implanted successfully with a follow-up of 36 +/- 8 months. So far no late failures have been seen. A longer test stimulation is needed in patients with pelvic pain because of a higher incidence of initial false positive tests. Our conclusion is that sacral nerve stimulation is effective in the treatment of therapy-resistant pelvic pain syndromes linked to pelvic floor dysfunction.

Sacral nerve stimulation results may be improved by electrodiagnostic techniques

Sacral nerve electrical stimulation (sacral neuromodulation) therapy for patients with refractory urge incontinence, frequency and urgency, and non-obstructive retention yields an effective 75%-80% success rate. Electrodes are surgically implanted if initial percutaneous stimulation testing has a successful clinical response. Unfortunately, up to 50% of patients are denied surgical implantation because of an unsuccessful response to the test stimulation. In this descriptive study, adding electrodiagnostic monitoring to the currently used biological monitoring techniques was associated with a reduction in the number of tested patients denied implantation to 20%. These findings suggest that the incorporation of electrodiagnostic techniques may improve the clinical efficacy of sacral stimulation therapy. Randomized prospective testing of this hypothesis is suggested.

Sacral neuromodulation in the treatment of urgency-frequency symptoms: a multicenter study on efficacy and safety

PURPOSE

Neuromodulation of sacral nerves has shown promising results in correcting voiding dysfunction. We report the results of a multicenter trial designed to assess the efficacy of sacral nerve neuromodulation in patients presenting with refractory urinary urgency-frequency.

MATERIALS AND METHODS

A total of 51 patients from 12 centers underwent baseline assessment, including a detailed voiding diary, urodynamic evaluation and percutaneous test stimulation of the sacral nerves at S3 and/or S4. All patients enrolled in the study had undergone prior conventional treatment, such as pharmacotherapy, hydrodistention and surgical intervention, which failed. All patients demonstrated a satisfactory response to trial stimulation and were randomly divided into a stimulation group (25 patients) and a control group (26). A sacral nerve stimulation device was implanted after 6 months in the control group. Patients were followed at 1, 3 and 6 months, and at 6-month intervals for up to 2 years after implantation of a neuroprosthetic InterStim* system. dagger The study variables included the number of voids daily, volume voided per void and degree of urgency before void.

RESULTS

Compared to the control group, 6-month voiding diary results demonstrated statistically significant improvements (p <0.0001) in the stimulation group with respect to the number voids daily (16.9 +/- 9.7 to 9.3 +/- 5.1), volume per void (118 +/- 74 to 226 +/- 124 ml.) and degree of urgency (rank 2.2 +/- 0.6 to 1.6 +/- 0.9). Patients in the control group showed no significant changes in voiding parameters at 6 months. Significant improvements in favor of the stimulation group were noted in various parameters with respect to water cystometry and quality of life (SF-36). At 6 months after implant, neurostimulators were turned off in the stimulation group and urinary symptoms returned to baseline values. After reactivation of stimulation sustained efficacy was documented at 12 and 24 months.

CONCLUSIONS

Neuromodulation of the sacral nerves is an effective, safe therapy that successfully treats significant symptoms of refractory urgency-frequency.

Surgical interruption of pelvic nerve pathways for primary and secondary dysmenorrhoea

BACKGROUND

Dysmenorrhoea is the occurrence of painful menstrual cramps of uterine origin and is a very common gynaecological complaint. Medical therapy for dysmenorrhoea includes oral contraceptive pills (OCP) and nonsteroidal anti-inflammatory drugs (NSAIDS) which both act by suppressing prostaglandin levels. While these treatments are very successful there is still a 20-25% failure rate and surgery has been an option for cases of dysmenorrhoea that fail to respond to medical therapy. Uterine nerve ablation (UNA) and presacral neurectomy (PSN) are two surgical treatments that have become increasingly utilised in recent years. These procedures both interrupt the majority of the cervical sensory nerve fibres, thus diminishing uterine pain. Uncontrolled studies have supported the use of these procedures for primary dysmenorrhoea however both operations only partially interrupt some of the cervical sensory nerve fibres in the pelvic area; therefore dysmenorrhoea associated with additional pelvic pathology may not always benefit from this type of surgery.

OBJECTIVES

To assess the effectiveness of surgical interruption of pelvic nerve pathways as treatment for primary and secondary dysmenorrhoea, and to determine the most effective surgical treatment.

SEARCH STRATEGY

Electronic searches of the Cochrane Menstrual Disorders and Subfertility Group Register of controlled trials, MEDLINE, and EMBASE were performed to identify relevant randomised controlled trials (RCTs). Attempts were also made to identify trials from citation lists of review articles and handsearching. In most cases, the first or corresponding author of each included trial was contacted for additional information.

SELECTION CRITERIA

The inclusion criteria were randomised comparisons of surgical techniques of interruption of the pelvic nerve pathways (both open and laparoscopic procedures) for the treatment of primary and secondary dysmenorrhoea. The main outcome measures were pain relief and adverse effects.

DATA COLLECTION AND ANALYSIS

Seven RCTs were identified that fulfilled the inclusion criteria for this review. One trial (Sutton 1994) was excluded because another treatment was given in combination with destruction of pelvic nerve pathways and the effects of these two treatments could not be separated. Of the remaining six trials, three were included in the meta-analysis (Chen 1996, Candiani 1992, Lichten 1987). The results of the other three trials (Dover 1999, Tjaden 1990, Vercellini 1997) were included in the text of the review for discussion because the data were not available in a form that allowed them to be combined in a meta-analysis.

MAIN RESULTS

For the treatment of primary dysmenorrhoea there is some evidence of the effectiveness of uterine nerve ablation (UNA) when compared to a control of no treatment. The comparison between UNA with presacral neurectomy (PSN) for primary dysmenorrhoea showed no significant difference in pain relief in the short term, however long term PSN was shown to be significantly more effective. For the treatment of secondary dysmenorrhoea the identified RCTs addressed only endometriosis. The treatment of UNA combined with surgical treatment of endometrial implants versus surgical treatment of endometriosis alone showed that the addition of UNA did not aid pain relief. For PSN combined with endometriosis treatment versus endometriosis treatment alone there was also no overall difference in pain relief, although the data suggests a significant difference in relief of midline abdominal pain. Adverse events were significantly more common for presacral neurectomy, however the majority were complications such as constipation, which may spontaneously improve.

REVIEWER'S CONCLUSIONS

There is insufficient evidence to recommend the use of nerve interruption in the management of dysmenorrhoea, regardless of cause. Future RCTs should be undertaken.

Peripheral nerves mediating penile erection in the rat

We examined the effects in male rats of bilateral transection of two nerves previously implicated in erectile function, the viscerocutaneous branch of the pelvic nerve (Vc) and the hypogastric nerve (HgN). In Experiment 1 (conducted in Storrs), males underwent simultaneous or successive section of Vc and HgN and were tested for copulation, reflexive erection, and noncontact erection (NCE), i.e. in response to remote cues from estrous females. NCE is considered to be analogous to 'psychogenic' erection in humans, for which the HgN has been ascribed a significant role. In all three types of test, males had a moderate to severe deficit in erectile function after Vc transection. Section of HgN alone had no apparent pro- or anti-erectile effect in any context, nor did it affect the decrement resulting from Vc surgery. Regardless of treatment, all groups retained some erectile potential in each type of test. The loss of bladder function after Vc surgery and of seminal plug deposition after HgN section gave evidence that the targeted nerves were in fact severed. In Experiment 2 (conducted in Xalapa), males were tested only for NCE, but (a) they were tested every 3 days beginning 3 days after each surgery, (b) the interval between the two surgeries was more than 2 weeks, rather than 1 week as in Experiment 1, to allow more time for recovery from general effects of surgery and for hypothetical plasticity of neural function. In the first test after the first surgery, all groups had a modest reduction in the proportion of males displaying NCE, relative to sham-operated males. However, this deficit did not extend to measures of NCE latency or number, and was absent after the second test. After the second surgery, when all males except those with sham operations had both nerves cut, none of the groups exhibited a significant deficit in NCE, and all groups had at least one test in which at least half the males responded. Thus, (a) HgN section did not significantly impair NCE, reflexive erection, or copulation; (b) Vc section impaired, but did not eliminate, erection in all three contexts, but even those effects may be transient; and (c) transection of both nerves, simultaneously or successively, did not cause a greater impairment in erection than did cutting just the Vc. We infer that the HgN may have no pro-erectile role in erection in rats, even in a model analogous to psychogenic erection. The Vc is probably the most important nerve mediating pro-erectile function in NCE, as in reflexive erection and copulation, but this nerve may not be essential for erection in rats in any context, at least in some males.

Effects of short term sacral nerve stimulation on anal and rectal function in patients with anal incontinence

BACKGROUND

Some patients with faecal incontinence are not amenable to simple surgical sphincter repair, due to sphincter weakness in the absence of a structural defect.

AIMS

To evaluate the efficacy and possible mode of action of short term stimulation of sacral nerves in patients with faecal incontinence and a structurally intact external anal sphincter.

PATIENTS

Twelve patients with faecal incontinence for solid or liquid stool at least once per week.

METHODS

A stimulating electrode was placed (percutaneously in 10 patients, operatively in two) into the S3 or S4 foramen. The electrode was left in situ for a minimum of one week with chronic stimulation.

RESULTS

Evaluable results were obtained in nine patients, with early electrode displacement in the other three. Incontinence ceased in seven of nine patients and improved notably in one; one patient with previous imperforate anus and sacral agenesis had no symptomatic response. Stimulation seemed to enhance maximum squeeze pressure but did not alter resting pressure. The rectum became less sensitive to distension with no change in rectal compliance. Ambulatory studies showed a possible reduction in rectal contractile activity and diminished episodes of spontaneous anal relaxation.

CONCLUSIONS

Short term sacral nerve stimulation notably decreases episodes of faecal incontinence. The effect may be mediated via facilitation of striated sphincter muscle function, and via neuromodulation of sacral reflexes which regulate rectal sensitivity and contractility, and anal motility.

The effect of vaginal delivery on anal function

The commonest cause of faecal incontinence is considered to be childbirth. In this review we consider the available data on the prevalence of faecal incontinence in the community and the incidence of incontinence after childbirth. The results and implications of studies on childbirth using anal manometry, neurophysiological tests and anal ultrasound are discussed. The development of symptoms are more likely with a third degree tear and forceps delivery. Reduced resting and squeeze pressures are seen early after vaginal delivery with recovery noted with time. Reduced pressures have been seen in symptomatic and asymptomatic women and there is no correlation of the pressures with the presence or absence of a sphincter defect or evidence of pudendal neuropathy. Anal manometry can not be used as an indication of muscle or nerve injury. Both sphincter defects and evidence of pudendal neuropathy are common after vaginal delivery but these are not necessarily associated with symptoms. It is suggested that such occult sphincter injuries may go on to be symptomatic in later life. The number of these injuries, however, is far greater than the documented prevalence of incontinence in the community, and hence many must remain asymptomatic. Their true clinical significance remains uncertain.

Action of mannitol in ciguatoxin-intoxicated rats

This study reports the effects of mannitol on nerve conduction when used as a therapeutic agent in mammals following the administration of ciguatoxin. Electrophysiological studies were performed in vivo on the rat ventral coccygeal nerve. The absolute and relative refractory periods, conduction velocity and the supernormal response were measured in rats treated with i.p. ciguatoxin, both prior to, and following, the infusion of i.v. mannitol. Ciguatoxin induced significant prolongation of the absolute refractory period as well as significant slowing of the compound nerve conduction velocity. The magnitude of the supernormal response was significantly increased and the duration of the supernormal period extended in ciguatoxin-treated animals. Recordings collected following the infusion of mannitol in these ciguatoxin-treated animals showed that mannitol did not reverse the effects of ciguatoxin on nerve conduction in any of the parameters measured.

Urethral pudendal afferent-evoked bladder and sphincter reflexes in decerebrate and acute spinal cats

Electrical stimulation of the urethral sensory pudendal nerve in decerebrate or acute spinal cats was used to evoke micturition reflexes in animals that failed to respond to bladder distension. In the decerebrate animals, stimulation of urethral afferents evoked voiding characterized by a large bladder pressure increase coordinated with a simultaneous decrease in external urethral sphincter activity. In animals in which the spinal cord was transected between T10 and L6, electrical stimulation of the urethral afferents evoked small increases in bladder pressure that were insufficient to expel fluid but the contractions were coordinated with a decrease in external urethral sphincter activity. It was concluded that in addition to interacting with spinobulbospinal micturition pathways, urethral pudendal afferents may have direct access to a spinal circuitry that can coordinate bladder and sphincter activity.

Selective detrusor activation by electrical stimulation of the human sacral nerve roots

The purpose of this study was to investigate the feasibility of selective detrusor activation without activation of the urethral sphincter by sacral root stimulation in patients. The sacral roots were stimulated using a tripolar electrode. An anodal block was used to prevent the urethral sphincter from contraction. Using square current pulses (700 microseconds, 6-7 mA), no increase in intraurethral pressure was measured, while a normal increase in intravesical pressure occurred. The minimum pulse duration to obtain a complete block was 550 microseconds. The study shows that anodal blocking of action potentials is possible in humans and can result in selective detrusor activation when used in sacral root stimulation.

Interneurones mediating presynaptic inhibition of group II muscle afferents in the cat spinal cord

1. To investigate whether dorsal horn interneurones with input from group II muscle afferents induce depolarization of sensory fibres, simultaneous recordings were made from single interneurones in the sacral segments and from sacral dorsal root filaments using the spike-triggered averaging technique. 2. The spike potentials of eighteen out of thirty-eight interneurones tested were followed by dorsal root potentials (DRPs). The DRPs occurred at latencies of 2 and 6-8 ms. Interneurones evoking DRPs at latencies of up to 2 ms are considered likely to be last-order interneurones in pathways of presynaptic inhibition, while those inducing DRPs at longer latencies are considered likely to be first-order interneurones. The former were activated by peripheral afferents with somewhat longer latencies than the latter. However, all interneurones were co-activated by group II muscle and cutaneous afferents, indicating that the depolarization of group II muscle afferents, which these afferents induce, may be mediated by the same interneurones. 3. DRPs evoked by electrical stimulation of peripheral nerves were recorded from both sacral and midlumbar dorsal root filaments. The amplitudes of these DRPs were closely related to the potency with which group II afferents of various nerves activate dorsal horn interneurones in the sacral and midlumbar segments and group II afferents contributed to them more effectively than group I afferents. The second stimulus in a train was more effective than the first, while a third stimulus had little additional effect, indicating that the interneurones involved are relatively easily activated. 4. Intraspinal stimuli applied within the dorsal horn, at the sites where the largest field potentials of group II origin were recorded, evoked distinct DRPs. However, the location of the first- and last-order interneurones in pathways of primary afferent depolarization (PAD) could not be differentiated by this approach because the same stimuli induced positive potentials, which masked the onset of DRPs and precluded localization of the sites from which DRPs might be evoked monosynaptically.

Organization of neuronal systems mediating presynaptic inhibition of group II muscle afferents in the cat

1. The organization of neuronal systems mediating presynaptic control of transmission from group II muscle afferent fibres has been investigated by comparing the sources of presynaptic inhibition of fibres terminating in different segments of the spinal cord: fibres of the semitendinosus and lateral gastrocnemius muscle nerves terminating in the sacral segments and of the tibialis anterior and extensor digitorum longus muscle nerves terminating in the midlumbar segments. 2. Two measures of presynaptic inhibition were used: depolarization of the terminals of group II fibres (detected as changes in the excitability of single fibres to electrical stimuli) and a decrease in the effectiveness of their synaptic actions (detected as a decrease in the amplitude of monosynaptic field potentials evoked by group II muscle afferents). 3. Group II muscle afferents strongly depolarized all of the group II afferent fibres, while group I muscle afferents contributed to the depolarization of only a few. The majority of fibres were as effectively depolarized by cutaneous afferents as by the most effective muscle afferents. However, the effectiveness with which afferents of different nerves depolarized group II muscle afferent fibres in the sacral and midlumbar segments differed. The most effective afferents were those of nerves that provide the main input to dorsal horn interneurones in the same region of the spinal cord. The sources of depolarization of flexor and extensor fibres terminating in the same (sacral) segments were very similar. 4. The amplitudes of field potentials evoked by group II afferents were depressed by the same types of afferent as produced depolarization of group II afferent fibres. There was also a strong correlation between the effectiveness with which afferents of a given nerve induced depolarization of single fibres and depression of field potentials in the same segments. Since group II field potentials were depressed to a greater extent (by up to 90%) than group I field potentials (by no more than 20%) concurrently recorded in the intermediate zone of midlumbar segments, it appears that transmission from group II muscle afferents may be more strongly affected by presynaptic inhibition than that from group I muscle afferents. 5. The results suggest that the interneuronal systems responsible for the presynaptic control of transmission from group II muscle afferents have topographically restricted actions and an organization appropriate to a system of negative feedback control.

Sacral nervous function, hormonal levels and sexuality in premenopausal women before and after hysterectomy

OBJECTIVE

To investigate the predictive value of sacral nervous function, result of pelvic examination and hormonal status on sexuality before and after subtotal hysterectomy.

MATERIAL AND METHOD

One hundred and four women were examined and interviewed one month before and one year after hysterectomy for non-malignant diseases. Genital examination, sacral nervous function testing including vibrotactility were performed, and sex hormone levels were estimated at each occasion. The results were evaluated and compared using multivariate analyses.

RESULTS

Postoperative experience of multiple orgasm was negatively correlated to three out of five measured factors for pelvic sacral function: i.e. vibrotactility of the clitoris, the external anal reflex and the levator muscle strength. No correlations were found between tests for sacral nervous function and a latent factor for sexuality before and after the operation. Preoperative uterine size did not show correlation to either preoperative or postoperative sexual parameters nor did uterine pain during vaginal examination. The preoperative sex hormone levels, and the result of histopathological examination showed no correlation to sexual variables.

CONCLUSION

Preoperative somatic findings including sacral nervous function and pelvic muscular strength cannot be used as predictors for sexuality after subtotal hysterectomy.

Increased vaginal blood flow induced by implant electrical stimulation of sacral anterior roots in the conscious woman: a case study

The sacral anterior nerve roots were stimulated in a conscious female paraplegic by means of an intradural implanted Finetech/Brindley stimulator activated by inductive radio signals. Changes in vaginal blood flow were monitored by a photoplethysmograph. Stimulating S2 and S3 (but not S4) caused significant increases in vaginal pulse amplitude indicating genital vasodilation and increased blood flow.