Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SACRAL PLEXUS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 433 records · Page 24Linked to original sources
PubMed2003

Improved sacral neuromodulation in the treatment of the hyperactive detrusor: signal modification in an animal model.

OBJECTIVE: To investigate different stimulation signals for the peripheral nerve evaluation test (PNE, carried out before implanting a sacral neuromodulator for functional voiding dysfunction) in an animal model and to determine their efficacy, as up to 80% of patients do not respond to the PNE test. MATERIALS AND METHODS: PNE foramen electrodes were placed in the S3 of 12 anaesthetized Göttingen minipigs. First, detrusor instabilities were induced by the intravesical instillation of formalin. A 10-min stimulation phase with both a quasi-trapezoidal (QT) signal and a rectangular signal followed. An interval of 30 min elapsed between the series of stimulations. The attained bladder pressure values were registered on a urodynamic unit and evaluated as contractions and amplitudes per minute. Six minipigs were treated in the same way but were not stimulated and served as a control group. RESULTS: After formalin instillation, the mean (sd) number of involuntary detrusor contractions was 3.5 (0.8)/min and the sum of amplitudes 7.2 (1.1) cmH2O/min. Subsequent NaCl instillation and QT-stimulation reduced the contractions to 0.3 (0.3)/min and the sum of amplitudes to 0.8 (0.4) cmH2O/min. Stimulation with a rectangular signal, as used in the PNE test, followed after an interval of 10 min, giving 1.1 (0.1) contractions/min and a sum of amplitudes of 5.1 (2.4) cmH2O/min. Within the control group there was no significant reduction. CONCLUSIONS: These results show that QT-stimulation suppresses uncontrollable detrusor contractions in the minipig more effectively than the conventional rectangular stimulation presently applied in sacral neuromodulation.

Animals↗
PubMed1987

Generators of human spinal somatosensory evoked potentials.

Somatosensory evoked potentials recorded over the spine with a noncephalic reference following posterior tibial nerve stimulation have several components. (1) A stationary, synapse-dependent, negative potential (N22) occurs synchronously with a positive potential, P22, recorded ventral to the spinal cord and is localized to the lumbar region overlying the lumbar root entry zone. The N22/P22 complex is attributed to activation of interneurons in the dorsal gray of the lumbar cord. (2) A traveling negative potential with a gradually increasing latency may be recorded from the sacral to the cervical region. Its short refractory period indicates that it is not dependent on transmission across a synapse. This activity is attributed to transmission of the afferent volley through the lumbosacral plexus, roots, and the dorsal columns of the spinal cord. (3) N29, a stationary, synapse-dependent negative potential, localizes to the rostral cervical spine and is attributed to activation of the gracile nucleus relay cells. Following stimulation of the median nerve or fingers, the waveforms recorded over the cervical spine with a noncephalic reference include (1) the proximal plexus volley, a traveling negative potential reflecting transmission through the proximal brachial plexus and roots; (2) the dorsal column volley (DCV), the latency of which gradually increases from the caudal to rostral cervical region (the DCV is attributed to transmission of the afferent volley through the dorsal columns of the cervical cord); and (3) N13, a stationary negative waveform, with a long refractory period consistent with its dependence on transmission across a synapse. Experimental animal and human studies indicate that the N13 waveform is dependent on activity of at least two generator sites, namely the dorsal gray of the cervical cord and the cuneate nucleus.

Evoked Potentials, Somatosensory↗
PubMed1998

Bilateral chronic sacral neuromodulation for treatment of lower urinary tract dysfunction.

PURPOSE: Chronic sacral neuromodulation aims at functional restoration of selected forms of nonneurogenic and neurogenic bladder dysfunction. The original technique, as described by Tanagho and Schmidt, provides unilateral sacral nerve stimulation via an implanted stimulator powering an electrode inserted into a sacral foramen. Its drawback was that the implant failed unpredictably in some patients despite previous successful percutaneous test stimulation. Therefore, we modified the stimulation technique to improve the efficacy of chronic sacral neuromodulation. MATERIALS AND METHODS: Guarded bipolar electrodes powered by an implantable neurostimulator were attached bilaterally directly to the S3 nerves through a sacral laminectomy in 9 women and 2 men (mean age 43.4 years). Of the patients 5 had urinary incontinence due to detrusor hyperactivity and 6 had urinary retention from detrusor hypocontractility. Mean followup with repeated urodynamics was 13 months (range 9 to 28). RESULTS: Four significant complications were encountered in 4 patients. In 10 patients the urological sequelae of the neurological disorder were alleviated significantly (50% or more), including 5 who experienced complete relief of symptoms. CONCLUSIONS: The efficacy of chronic sacral neuromodulation can be improved by bilateral attachment of electrodes directly to the sacral nerves.

Adult↗
PubMed2004

Sacral nerve stimulation: an emerging treatment for faecal incontinence.

Faecal incontinence is common, distressing to the patient and socially incapacitating. The treatment options depend on the severity and aetiology of incontinence. For mild cases of faecal incontinence, medical management and pelvic floor physiotherapy may be adequate. For more severe cases, surgery is often required. Patients who have a distinct sphincter defect are amenable to surgical repair. In many cases, there is a combination of diffuse structural damage of the anal sphincters with pudendal neuropathy. Conventional surgical repairs have a modest degree of success and the results tend to deteriorate with time. Neosphincter procedures such as artificial bowel sphincter and dynamic graciloplasty are potentially morbid and technically complex. Sacral nerve stimulation is innovative and has had a medium-term success with improvement of quality of life in over 80% of patients treated for faecal incontinence. These results are superior to other techniques in treating patients with severe refractory faecal incontinence, where current maximal therapy has failed. The technique is unique because there is a screening phase, which has a high predictive value. It is also associated with minimal complications that are usually minor. However, most published reports of sacral nerve stimulation for treatment of faecal incontinence were case studies and methods of assessing outcome were variable. Criteria for patient selection are evolving and are yet to be defined. The present paper critically reviews the publications to date on sacral nerve stimulation for treatment of faecal incontinence. This will form the basis for future evaluation of this emerging treatment of severe, intractable faecal incontinence. Randomized clinical trials like that of the Melbourne trial will further clarify the role and indications of sacral nerve stimulation for faecal incontinence.

Electric Stimulation Therapy↗
PubMed2004

A rat model for studying effects of sacral neuromodulation on the contractile activity of a chronically inflamed bladder.

OBJECTIVE: To develop an animal model in which the effects of electrical stimulation of the sacral nerves (sacral neuromodulation) on a chronic hyperactive urinary bladder can be studied. MATERIALS AND METHODS: In female rats the urinary bladder was instilled with mustard oil (0.4%); after 10 days the animals were anaesthetized with intraperitoneal urethane, the bladder catheterized and connected to a pressure transducer. Stimulating electrodes were placed into the sacral foramina bilaterally. The intensity and duration of sacral electrical stimulation was varied systematically to determine the effects of the sacral neuromodulation on bladder contractions. RESULTS: The main effect of the neuromodulation was an increase in the interval between contractions, i.e. during and for some time after the stimulation the contractions were completely abolished. The duration of the pause increased with the intensity and duration of stimulation. After the contractions had reappeared the frequency of contractions was reduced for a long period. In animals with chronic cystitis the effects of neuromodulation tended to be stronger (the pauses were longer) than in control animals with an intact bladder, but only in one test (increase of pause length with stimulus duration) was the difference statistically significant. CONCLUSIONS: The results show that this animal model is suitable for studying the effects and mechanisms of sacral neuromodulation on a chronic hyperactive urinary bladder.

Animals↗
PubMed2005

Sacral nerve stimulation: Interstim therapy.

Sacral nerve stimulation is a young but promising technique in the treatment of chronic voiding dysfunctions. Electrical stimulation of the S3 nerve--using a pacemaker device--is able to treat a wide range of pelvic floor dysfunctions. This article gives a brief review on the indications, mechanisms of action and possible complications of this technique. Furthermore, new evolutions in the domain of sacral nerve modulation are discussed.

Electric Stimulation Therapy↗
PubMed2006

The current use of neuromodulation for bladder dysfunction.

Neuromodulation utilizes electrical stimulation to alter the function of an organ. Recent advances in technology and improved knowledge of micturition physiology have coincided with the growth of neuromodulation for the treatment of urinary urgency/frequency, urge incontinence and non-obstructive urinary retention. Currently, the most common modality for bladder neuromodulation involves stimulation through the S3 foramen, or sacral neuromodulation. This review will highlight the current indications, patients selection, implantation options/techniques, outcomes and complications of sacral neuromodulation. In addition, other methods of neuromodulation will be discussed.

Electric Stimulation Therapy↗
PubMed1985

[Intrathecal alcohol neurolysis of the lower sacral roots in inoperable rectal cancer].

Intrathecal neurolytic blocks are performed with either 95% alcohol or with 6-8% phenol in glycerin. Alcohol is hypobaric and phenol hyperbaric compared with the cerebrospinal fluid; positioning of the patient must therefore be done accordingly. This is a report about 67 consecutive neurolytic alcohol blocks of the lower sacral roots. Although lumbar puncture is done at the lowest possible level at L5-S1, the block only affects the roots from S3 or S4 downwards. The detailed anatomy of the caudal dural sack reveals why S1 and S2 are not affected. S1 and S2 contribute to the lumbosacral plexus and are important for the innervation of the lower extremities. However in patients with very low CSF pressure, S2 and S1 might become damaged. This is the most important result of this series. To avoid an unexpected extension of the block in patients with very low CSF pressure, we now recommend that synthetic CSF be instilled prior to alcohol. The results were unsatisfactory in patients with perineal pain and pain in the lower extremities as well. In these cases S2 or S2 + S1 are already affected by the tumor. One should employ other therapeutic procedures (e.g., epidural morphine) for these patients. After careful selection of patients, alcohol neurolysis of the lower sacral roots is a useful procedure.

Ethanol↗
PubMed2001

Quantitative analysis of the dendrites of sacral preganglionic neurons in the cat.

Quantitative analyses were performed on the dendrites and somata of 25 electrophysiologically identified preganglionic neurons (PGN) obtained from the sacral spinal cord of the cat by intracellular injection of Neurobiotin or horseradish peroxidase. Total dendritic length and surface area were measured for each dendrite. The sizes of the stem dendrites measured at their base were positively correlated with the sizes of the entire tree and numbers of end branches. Total surface area of somata and dendrites averaged 39,138 microm(2); 90.7% of that was from the dendrites. To obtain measurements of the relative contributions of PGN dendrites to specific regions of the spinal cord, the percentage of each dendrite occupying eight spinal cord regions was recorded. Sixty-three percent of the dendrites projected dorsal to their somata, whereas an average of 33.3% of dendrites were located in the white matter, most of them in the lateral and dorsolateral funiculi. The neurons within this sample formed a continuum with some neurons having a large percentage of dendrites in lamina I but little in the white matter, whereas at the other end of the continuum were cells with the reverse configuration. The intermediate neurons had dendrites in both locations. Taken together, these data indicate a heterogeneous population of PGN in the lateral band of the sacral parasympathetic nucleus.

Animals↗
PubMed1969

Reflexes to sacral parasympathetic neurones concerned with micturition in the cat.

1. Reflexes to sacral parasympathetic neurones were studied by electrophysiological techniques in decerebrate, in chloralose-anaesthetized, and in chronic spinal cats.2. Excitatory reflexes from pelvic nerve and sacral somatic afferent nerve fibres were present before and after chronic transection of the spinal cord, but the latencies differed markedly. It was concluded that the long-latency reflexes observed when the spinal cord was intact involved long-loop reflexes to the brain-stem. The weak, short-latency reflexes in the chronic spinal cat were never observed when the spinal cord was intact and could be due to reorganized spinal connexions. The short-latency reflexes are probably unimportant in normal micturition.3. Stimulation of afferent fibres in the pelvic or sacral somatic nerves produced short-latency inhibitory post-synaptic potentials (IPSPs) and inhibition of discharges in parasympathetic neurones. This inhibition was due to a spinal reflex.4. A local reflex was demonstrated in the pelvic plexus. This was probably a cholinergic axon reflex, but the remote possibility that it was a local cholinergic reflex involving sensory neurones in the bladder wall has not been excluded.

Animals↗
PubMed1992

Mechanoreceptor afferent activity compared with receptor field dimensions and pressure changes in feline urinary bladder.

The relationship between vesical mechanoreceptor field dimensions and afferent nerve activity recorded in pelvic plexus nerve filaments was examined in chloralose-anesthetized cats. Orthogonal receptor field dimensions were monitored with piezoelectric ultrasonic crystals. Reflexly generated bladder contractile activity made measurements difficult, therefore data were collected from cats subjected to actual sacral rhizotomy. Afferent activity was episodic and was initiated at different pressure and receptor field dimension thresholds. Maximum afferent activity did not correlate with maximum volume or pressure. Furthermore, activity was not linearly related to intravesical pressure, receptor field dimensions, or calculated wall tension. Pressure-length hysteresis of the receptor fields occurred. The responses of identified afferent units and their associated receptor field dimensions to brief contractions elicited by the ganglion stimulant 1,1-dimethyl-4-phenylpiperazinium iodide (2.5-20 micrograms i.a.), studied under constant volume or constant pressure conditions, are compatible with bladder mechanoreceptors behaving as tension receptors. Because activity generated by bladder mechanoreceptors did not correlate in a simple fashion with intravesical pressure or receptor field dimensions, it is concluded that such receptors are influenced by the viscoelastic properties of the bladder wall. Furthermore, as a result of the heterogeneity of the bladder wall, receptor field tension appears to offer a more precise relationship with the activity of bladder wall mechanoreceptors than does intravesical pressure.

Animals↗
PubMed1977

The use of sacral nerve blocks in the evaluation and treatment of neurologic bladder disease.

We describe the use of sacral nerve blocks in conjunction with air cystometry and sphincter electromyography to determine the functional innervation of the bladder and sphincters. This technique has aided in the selection of patients for sacral rhizotomy. Phenol sacral nerve blocks have been used successfully in treating hyperactive bladder disease and intractable perineal pain.

Humans↗
PubMed1993

Sacral reflex latencies in tethered cord syndrome.

We performed electrophysiologic evaluation in three adult patients with diagnosis of tethered cord syndrome confirmed by magnetic resonance imaging. In addition to lower motor neuron lesion signs in the lumbar and sacral myomeres we noticed shortened latencies for the H and bulbocavernosus reflexes. H reflex latencies ranged from 23.3 to 26.0 ms; bulbocavernosus reflex latencies ranged from 18.2 to 20.2 ms. The low location of the conus medullaris accounts for the shortening of the monosynaptic H reflex and for a part of the shortening of the polysynaptic bulbocavernosus reflex, anoxia of the conus being probably another important factor. In the absence of previous description of alternative pathology accountable for such a shortening, our observations suggest that shortened sacral reflex latencies might be specific of the tethered cord syndrome.

Female↗