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Sacralization of epidural block with repeated doses of 0.25% bupivacaine during labor.

A descriptive analysis of the progression of epidural block with repeated doses of 0.25% bupivacaine was performed, assessing pain relief (visual analog scoring), dermatomal spread of sensory and motor block, and the associated management and outcome of labor. The influence of epinephrine 1:200,000 on these observations was also assessed by the random assignment of study patients into two groups, one receiving 10 ml of 0.25% bupivacaine plain (n = 28) and another group receiving 10 ml of 0.25% bupivacaine with commercially added epinephrine 1:200,000 (n = 27). Only primigravid patients were studied. Data comparisons were considered significant at p less than 0.05. With repeated doses of 0.25% bupivacaine, administered within fixed dosing intervals of 60-90 minutes, there was an increasing spread of sensory block toward sacral dermatomes while the upper level of sensory block did not change. Sacral sensory analgesia was present in only 3.5% of patients after the first dose of bupivacaine but was evident in 63.2% of patients following the fourth epidural injection. A similar increase in the number of patients with significant motor weakness was also seen as the number of top-up doses increased. A comparison of patients receiving plain solutions and epinephrine containing bupivacaine showed similar demographic profiles between the groups. Both groups received a similar dose of bupivacaine and experienced comparable management and outcome of labor. Epinephrine in a 1:200,000 concentration did not influence the changing characteristics of the epidural block over time. The duration of labor was not significantly different between groups (10.3 +/- 5.2 hours for the plain group and 11.0 +/- 4.7 hours for the epinephrine group).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Effect of sacral neuromodulation for faecal incontinence on sexual activity.

INTRODUCTION: Faecal incontinence affects a percentage of the population and can have a significant effect on their ability to establish and maintain sexual relations. PATIENTS AND METHODS: Sixteen consecutive patients with permanent sacral neuromodulation (SNM) for faecal incontinence completed a 'Sex Life Questionnaire' at their follow up visit to ascertain whether there was any improvement in this aspect of their life. RESULTS: Nine of the sixteen patients was sexually active. These nine patients (median age 56 (35-61) years) had a significant reduction in faecal incontinence episodes per week from a median of 12 (1-55) to 1.5 (0-8.5) (P = 0.008). All nine patients reported that their sex life had been affected by feacal incontinence prior to SNM and seven had felt benefit from implantation. The median improvement in their sex life was 40% (1-100) and the percentage improvement was inversely correlated to age (r = -0.834, P = 0.005). CONCLUSION: SNM improves the quality of sexual activity in 78% of patients. More improvement seems to be gained the younger the patients.

Adult↗

The recognition of mechanically induced pelvic pain and organic dysfunction in the low back pain patient.

Mechanical disorders of the lumbar spine have been identified as a cause of pelvic pain and organic dysfunction (PPOD). Categorically, the clinical features indicative of mechanically induced PPOD fall into three areas: the history of the development or onset of pelvic symptomatology attributable to lower sacral nerve root compression (LSNRC), identification of related symptomatology on presentation, and the recognition of clinical findings indicative of mechanically induced PPOD on examination. Characteristic features of each category are presented. The clinical signs that most reliably indicate the presence of PPOD secondary to a mechanical lesion of the low back are of a sensory nature, and the disappearance or lack of improvement of these signs closely parallels the patient's overall response to manipulative treatment. Without a thorough understanding of the salient features of mechanically induced PPOD, the practitioner is likely to overlook this as a diagnostic possibility. As a result, efforts to document chiropractic spinal manipulative therapy in relieving disorders of pelvic organic function may be hampered. The empirical efficacy of chiropractic spinal manipulative therapy for treating disorders of pelvic organic function would be enhanced if more chiropractors were apprised of the salient features indicating the presence of mechanically induced PPOD.

Back Pain↗

[An electromyographic study of the feline urethral rhabdosphincter in the normal state and after sacral rhizotomy. Part 1. Characteristics of action potentials of the rhabdosphincter and micturition and continence reflexes].

To investigate functional property of the urethral rhabdosphincter, the male feline rhabdosphincter was examined by means of electromyography using fine electrodes. Experiments were performed on 28 normal (N group) and 13 rhizotomized cats under chloralose anesthesia, the latter being further divided into two groups: 4 cats of 1-3 weeks (SR group) and 9 cats of 10-24 weeks (LR group) after complete sacral rhizotomy. Frequency of action potentials of the rhabdosphincter at empty bladder in N, SR and LR group was 1.8 +/- 0.3, 16.4 +/- 2.0, 8.9 +/- 1.4 spikes/sec, respectively, with significant difference between N and the other two groups and also between SR and LR group. Spontaneous discharges of the rhabdosphincter in SR and LR group were not abolished after neuromuscular junction blockade. The duration of action potentials of the rhabdosphincter in N, SR and LR group was 3.34 +/- 0.08, 1.71 +/- 0.07, 1.72 +/- 0.04 ms, respectively, with significant difference between N and the other two groups. Micturition reflex was negative in both SR and LR groups, but in 7 cats of LR group with dorsal roots preserved, activities of the rhabdosphincter increased reflexly by vesicourethral or urethrourethral contraction reflex, while they did not in 2 cats of LR group without preservation of dorsal roots and in SR group. Bulbocavernosus reflex was negative in both SR and LR groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗

Urodynamic study of women in urinary retention treated with sacral neuromodulation.

PURPOSE: We investigated the action of sacral neuromodulation in restoring voiding function in women with urinary retention attributable to sphincter overactivity (Fowler's syndrome). MATERIALS AND METHODS: We recruited women within retention who were able to void following neuromodulation by temporary test stimulation or a permanent implant. Urethral pressure profiles, cystometry and sphincter electromyography were performed before and after neuromodulation. RESULTS: A total of 30 women 19 to 52 years old were recruited, including 21 with a permanent implant and 9 undergoing temporary stimulation. Mean maximum urethral closure pressure was elevated compared to expected pressure and it did not change significantly after neuromodulation. The electromyographic abnormality persisted during neuromodulation and voiding was often done with an interrupted flow. There was a slight increase in detrusor contractility. CONCLUSIONS: This evidence suggests that neuromodulation does not restore voiding in these patients by a direct relaxant effect on the sphincter. The modest increase in detrusor pressure appears to be sufficient to overcome the resistance of the overactive sphincter.

Adult↗

First Scandinavian experience of electrical sacral nerve stimulation in the treatment of the overactive bladder.

OBJECTIVE: This study aimed to evaluate the efficacy of electrical sacral nerve stimulation (SNS) in the treatment of urinary incontinence and urinary retention refractory to conservative treatment, and to assess the impact of urodynamic abnormalities and electrode position. MATERIAL AND METHODS: Thirty patients (10 men, 20 women) with a mean age of 59 years (range 21-79 years), all of whom had longstanding symptoms ranging from 2 to 46 years (mean 12.4 years), were subjected to a percutaneous test stimulation. Ten patients responded well, resulting in a permanent implant in nine patients. Electrode positions were determined by plain X-ray and computed tomography. RESULTS: Radiologically, a variety of positions of the temporary electrodes was seen. In the implanted patients, long-term symptom reduction varied over time, ranging from total relief to partial or total recurrence of symptoms. CONCLUSIONS: SNS is a new promising option for the treatment of urge incontinence. Refined instruments for proper patient selection and the optimal way to position the electrode remain to be developed.

Adult↗

[Results of sacral nerve modulation for treatment of overactive bladder].

Currently, sacral nerve modulation (SNM) is an effective treatment for overactive bladder symptoms which are refractory to anticholinergic or muscarinergic treatment. However, SNM requires the implantation of stimulation electrodes at the sacral nerves and a subcutaneous impulse generator. The SNM procedure can be divided into three phases: the acute phase comprising the implantation of the test stimulation electrodes, the subchronic stimulation phase over a period of 7-14 days during which neurostimulation takes place by means of an external impulse generator, and finally chronic SNM after implantation of the final impulse generator. In 1981 the SNM technique for treatment of bladder dysfunctions was first developed by Tanagho and Schmidt and has since been refined, while the range of indications has been extended continuously. It has been shown that patients with neurogenic bladder dysfunctions are able to gain the greatest benefit from SNM. The long-term results of SNM are very encouraging so far. In addition, a highly innovative and promising technique is the implantation of a miniaturized impulse generator with integrated stimulation electrode at the n. pudendus. However, the outcome of these trials has not fully been capable of living up to the expectations so far.

Clinical Trials as Topic↗

Alterations of cortical electrical activity in patients with sacral neuromodulator.

OBJECTIVES: Sacral neuromodulation represents chronic stimulation of the sacral (S3) nerve. So far, the mode of action and neuro-anatomical basis is unclear. Sacral reflex mechanisms as well as pontine or cortical centers of modulation have been postulated. Our aim was to evaluate possible alterations in electroencephalogram (EEG) activity as an indicator of a supraspinally mediated mechanism of sacral neuromodulation. MATERIALS AND METHODS: We analyzed serial EEGs (apparatus: Kölner Vitaport System) using electrodes placed at Fz, Cz, Cz' and Pz in 10 patients. Subsequently, the sacral (S3) nerve was stimulated by means of an impulse generator (Medtronic, Interstim 3023) using an on-off paradigm with a 1.5s "on" interval followed by a 10s stimulation break. Raw data were analyzed using both Matlab 4.0 software and a specially developed averaging routine. RESULTS: All patients demonstrated a cortical potential complex following sacral root stimulation with an early electronegative component at 50 ms with a mean amplitude of 23 microV followed by a late potential component with a mean latency of 253 ms and a mean amplitude of 5 microV, both with a maximum at Cz, corresponding to the post-central gyrus. This finding occurred irrespective of patient's reports of actually feeling the neuromodulator being switched on and off. CONCLUSION: In neuromodulation responders, both short and long latency cortical potentials can be reproduced with a maximum at the sensory cortical area. Although these potentials are similar to cognitively mediated "event-related potentials", they are clearly distinct from any subjective sensory or even painful response since several patients of this series have not been able to feel any neuromodulator action. Therefore, this pilot study indicates a supraspinally mediated site of modulation, most probably in sensory cortex areas.

Adult↗

Transmitter profile and spinal inputs of pelvic ganglion cells projecting with preganglionic axons along the hypogastric and pelvic nerves of the male rat.

Pelvic autonomic ganglion cells receive spinal preganglionic inputs via the hypogastric (lumbar) or pelvic (sacral) nerves. Damage to these nerves stimulates axogenesis (sprouting) from pelvic ganglion cells and two possible triggers are deafferentation (decentralisation) or, if some ganglion cells project centrally in these nerves, axotomy. We have used a combination of retrograde tracing and immunohistochemistry in male rats to identify the number of pelvic ganglion cells that project centrally along these nerves, their transmitter type and the spinal level of their preganglionic inputs. Only a small number (<1%) of pelvic ganglion cells project along these nerves; 29-65 project in each hypogastric nerve and 41-71 in each pelvic nerve. These neurons comprise of both cholinergic and noradrenergic classes and the majority receive preganglionic inputs from the nerve in which they also project. These results suggest that damage of the hypogastric and pelvic nerves close to the pelvic ganglion is unlikely to cause axotomy of many pelvic ganglion cells. Therefore deafferentation rather than axotomy is likely to be the primary trigger of axogenesis occurring in pelvic ganglia after these lesions.

Afferent Pathways↗

The influence of visceral mechanoreceptors on sympathetic efferent discharge in the cat.

1. Recordings have been made from eighty-three single sympathetic efferent units in the hypogastric nerve in two types of preparation. In all animals the baroreceptors were denervated to exclude changes in sympathetic discharge resulting from any variations in arterial pressure, and the spinal cord was sectioned at the 6th lumbar segment to exclude changes in efferent discharge that might have been due to pelvic nerve afferents from the bladder or other viscera. In some animals the afferent pathways were sectioned from all pelvic and lower abdominal viscera other than the bladder, so that the vesical afferent pathway was the only neural pathway that might mediate reflex events from these viscera. The hypogastric nerve afferent pathway was excited by bladder distension or by bladder contractions induced by electrical stimulation of the sacral cord.2. Approximately half the units gave an increase in spike rate during distension or during contraction of the bladder. Three-quarters of the units tested also gave an increase in spike rate during colonic distension. In no units that exhibited convergence of afferent input did colonic and vesical stimuli cause responses of opposite sign.3. Approximately 10% of units showed a reduction in discharge rate when the bladder was distended or caused to contract.4. The estimated intravesical pressure thresholds for these reflexes were in the range 8-56 mmHg which extends beyond that of the mechanoreceptors which form the afferent limb of the reflex.5. These reflex studies indicate that the hypogastric nerve afferents from the bladder can elicit sympathetic reflexes within the physiological range of intravesical pressures, and that vesico-sympathetic reflexes can be elicited in the absence of pelvic nerve afferent inputs.In 75% of sympathetic efferent units that respond to bladder distension or contraction, there is evidence for convergent inputs with similar actions from the colon.

Action Potentials↗

Differential regulation of trkA and p75 in noradrenergic pelvic autonomic ganglion cells after deafferentation of their cholinergic neighbours.

In rats, following lesion of lumbar or sacral preganglionic axons, many pelvic ganglion cells undergo axogenesis to form baskets of terminals around select populations of nearby ganglion cells. The aim of the current study was to address mechanisms underlying initiation of this sprouting, focusing on a possible role for nerve growth factor (NGF). Immunohistochemical localization of NGF receptors (trkA and p75) showed that virtually all noradrenergic and a minority of cholinergic pelvic neurons expressed both receptors. Terminals immunoreactive for each substance were found in pelvic viscera. In pelvic ganglia, many glial cells expressed p75 but not trkA, and very few lumbar or sacral preganglionic neurons expressed either receptor. Lumbar and/or sacral preganglionic inputs were removed from ganglion cells by cutting the hypogastric, pelvic or both nerves, and tissues analysed 8 days later. Levels of receptor expression in noradrenergic pelvic ganglion cells were estimated by calculating the proportion that were receptor-immunopositive, and quantifying the intensity of trkA or p75 immunofluorescence. No lesion had a significant effect on trkA expression, however, a marked decrease in p75 occurred after cutting pelvic nerves, i.e. after deafferentation of neighbouring cholinergic neurons. These injuries appeared to cause little overall change in glial p75 expression. This study shows that manipulations that trigger sprouting from noradrenergic pelvic neurons cause downregulation of p75 but not trkA. Interestingly, this is occurring while some of their target organs are synthesizing high levels of NGF. This contrasts with other NGF-sensitive cells, in which one or both receptor types are upregulated by increased exposure to the ligand. The current study is also the first to show a change in p75 expression in neurons that are neither deafferented nor axotomized.

Animals↗

Age-related changes in the morphology of preganglionic neurons projecting to the rat hypogastric ganglion.

The aim of this study was to investigate age-related changes in preganglionic neurons of the lumbar and sacral spinal cord of the male rat that may underlie impaired control of the urogenital system in old age. Preganglionic sympathetic and parasympathetic neurons of 4- and 24-month-old rats were identified by retrograde axonal tracing with cholera toxin subunit-B followed by immunocytochemistry. Labelled preganglionic neurons were scanned on the confocal microscope. Measurements were made of soma area, number of primary dendrites, number of dendritic branch points and total dendritic length. There were significant decreases in the number of dendritic branch points and total dendritic length of sympathetic preganglionic neurons in the aged rats compared to the adult group. The soma area and number of primary dendrites were not significantly different. Some cells exhibited signs of degeneration, such as swelling of the soma and distension of the proximal part of primary dendrites. No significant differences were found in any of the parameters measured for the parasympathetic neurons. The changes in dendritic morphology of sympathetic preganglionic neurons may reflect altered central and peripheral control of pelvic viscera in old age.

Aging↗

Suppression of kainate-evoked AMPA receptor mediated responses by lanthanum in rat sacral dorsal commissural neurons.

The effect of lanthanum (La) on kainate (KA) responses in neurons acutely dissociated from the rat sacral dorsal commissural nucleus (SDCN) was investigated using the nystatin-perforated patch-recording configuration under voltage-clamp conditions. The responses to KA were mediated by activation of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors in SDCN neurons. La(3+) reversibly inhibited KA (100 microM) activated currents (I(KA)) in a concentration-dependent manner over the range from 30 microM to 30 mM, with IC(50) values of 0.64 +/- 0.06 mM at a holding potential (V(H)) of -40 mV. Our further study indicated that the effects of La(3+) on I(KA) were voltage independent. Moreover, the inhibition was not use dependent and was not overcome by increasing the concentration of agonist. These findings indicate that La(3+) is an efficacious inhibitor of AMPA receptor mediated responses which may contribute to its cytotoxic effect.

6-Cyano-7-nitroquinoxaline-2,3-dione↗

Neuromodulation for fecal incontinence: outcome in 16 patients with definitive implant. The initial Italian Sacral Neurostimulation Group (GINS) experience.

PURPOSE: Sacral nerve modulation appears to offer a valid treatment option for some patients with fecal incontinence and functional defects of the internal anal sphincter or of the striated muscle. METHODS: Sixteen patients with fecal incontinence (4 males; mean age, 51.4 (range, 27-79) years) with intact or surgically repaired (n = 1) anal sphincter underwent permanent sacral nerve stimulation implant. Cause was traumatic in two patients, and associated disorders included scleroderma (2 patients) and spastic paraparesis (1 patient); eight (50 percent) of the patients also had urinary incontinence, and two (12.5 percent) had nonobstructive urinary retention. All patients were selected on the basis of positive findings from at least one peripheral nerve evaluation. The stimulating electrode was positioned in the S2 (1 patient), S3 (14 patients), or S4 (1 patient) sacral foramen. RESULTS: Mean follow-up was 15.5 (range, 3-45) months. Mean preimplant Williams score decreased from 4.1 +/- 0.9 (range, 2-5) to 1.25 +/- 0.5 (range, 1-2) (P = 0.01, Wilcoxon test), and the number of incontinence accidents for liquid or solid stool in 14 days decreased from 11.5 +/- 4.8 (range, 2-20) before implant to 0.6 +/- 0.9 (range, 0-2) at the last follow-up. Important manometric data were an increase in mean maximal pressure at rest of 37.7 +/- 14.9 mmHg (implantable pulse generator 49.1 +/- 18.7, P = 0.04) and in mean maximal pressure during squeeze (prestimulation 67.3 +/- 21.1 mmHg, implantable pulse generator 82.6 +/- 21.0, P = 0.09). CONCLUSIONS: Neuromodulation can be considered an option for fecal incontinence. However, an accurate clinical and instrumental evaluation and careful patient selection are required to optimize outcome.

Adult↗

Influence of sacral neuromodulation on electrosensation of the lower urinary tract.

PURPOSE: We prospectively investigated whether neuromodulation of the S3 root influences the sensory threshold to electrical stimulation in the lower urinary tract. MATERIALS AND METHODS: The study included 7 women and 3 men receiving S3 neuromodulation at 210 msec. and 25 Hz. with the Interstim PNE system for a mean of 5 days. Neuromodulation was done unilaterally in 6 cases and bilaterally in 4. The sensory threshold was determined by electrodes placed randomly against the mucosa of the empty bladder on the left and right sides, in the urethra in women, and in the prostatic and penile urethra in men. Thresholds were measured at each location with neuromodulation on and off. RESULTS: With bilateral neuromodulation on all 4 patients had a lower bladder threshold than with neuromodulation off. In unilateral neuromodulation the threshold was significantly lower during neurostimulation on the ipsilateral side. There was no effect on the threshold on the arm or in the urethra. The effect was noted in patients in whom neuromodulation was and was not clinically successful. CONCLUSIONS: Neuromodulation on S3 influences the nervous system involved in electrosensation of the bladder but not the skin afferent innervation or the nerves involved in urethral electrosensation. These data support the hypothesis that S3 neurostimulation is effective mainly through the afferent nervous system in the pelvic nerves.

Adult↗

Surgical anatomy of the pudendal nerve and its clinical implications.

A study of the surgical anatomy of the pudendal nerve (PN) was performed in 13 female and 7 male cadavers. The knowledge of the precise anatomy and anomalies of this important nerve would help in better localization of the nerve and its roots and branches for neurostimulation or for pudendal canal decompression in pudendal canal syndrome. Two routes were used in the dissection: gluteal and perineal. The PN was identified and its course was followed from its roots to its termination. The PN was composed of three roots derived from the 2nd, 3rd, and 4th anterior sacral rami (S 2,3,4). The roots received a contribution from S 1 in five cadavers and from S 5 in one. The three roots formed two cords. The first root continued as the upper cord while the second and third root fused together producing the lower cord. The PN was formed by union of the two cords a short distance proximal to the sacrospinous ligament, and then crossed the back of the ligament. In no specimen did the nerve cross the ischial spine. The inferior rectal nerve arose from the PN in the pudendal canal in 18 cadavers. In two cases it came out proximal to the canal; this would spare the two subjects the anorectal manifestations of the pudendal canal syndrome. As the PN crossed the back of the sacrospinous ligament, it gave origin to a branch that supplied the levator ani muscle. This branch was only found in male cadavers and we call it "accessory rectal nerve"; the levator ani muscle in such cadavers was doubly innervated on its perineal aspect.

Adult↗

Pelvic cancer pain.

Pelvic cancer causes several types of pain, i.e., visceral, neuropathic, and somatic pain. Somatic pain is due to stimulation of nociceptors in the integument and supporting structures, namely, striated muscles, joints, periosteum, bones, and nerve trunks by direct extension through fascial planes and their lymphatic supply. In 60% of patients with malignant disease of soft tissues, nerve trunk, and sacral invasion from carcinoma of the cervix, uterus, vagina, colon, rectum, and other tissues in women, and from penile, prostate, and colorectal carcinoma and sarcoma in men, they have neuropathic pain. The infiltration of the perineal nerves results in lumbosacral plexopathies and complete destruction of the nerve, including perineural lymphatic invasions producing symptomatic sensory loss, causalgia, and deafferentation. Visceral pain is the result of spasms of smooth muscles of hallow viscus; distortion of capsule of solid organs; inflammation; chemical irritation; traction or twisting of mesentery; and ischemia, or necrosis, and encroachment of pelvis and presacral tumors. Pain of these types is managed by different modalities depending on the age of the patient, the expected life expectancy, availability of invasive and non-invasive pain control modalities, and the resources of the patient, community, and health care agencies. Patients with pelvic cancer can live with less pain due to better pain-control modalities that are available today with the help of dedicated and caring algologists.

Afferent Pathways↗

[An electromyographic study of the feline urethral rhabdosphincter in the normal state and after sacral rhizotomy. Part 2. Responses of the rhabdosphincter to hypogastric nerve stimulation].

To investigate functional aspect of sympathetic innervation of the urethral rhabdosphincter, responses of the male feline rhabdosphincter to hypogastric nerve (HGN) stimulation were examined by means of electromyography using fine electrodes. Experiments were performed on 28 normal (N group) and 13 rhizotomized cats under chloralose anesthesia, the latter being further divided into two groups: 4 cats of 1-3 weeks (SR group) and 9 cats of 10-24 weeks (LR groups) after complete sacral rhizotomy. HGN stimulation (1 Hz, 0.3 ms pulse duration, 2-30 V) elicited responses of the rhabdosphincter in N and LR groups. In N group, HGN stimulation still elicited responses of the rhabdosphincter even after pudendal nerve was transected in advance, indicating that these evoked potentials were independent of somatic nerve inflow. The threshold stimuli and latencies of the evoked responses in N group (3.0 +/- 0.2 V, 81.7 +/- 5.7 ms, respectively) were not significantly different from those in LR group (2.9 +/- 0.3 V, 71.5 +/- 10.5 ms), but the amplitudes of the evoked responses were significantly larger in LR group than in N group (110 +/- 12 vs 18 +/- 2 microV, p less than 0.001). These evoked responses of the rhabdosphincter were resistive to prazosin (0.2 mg/kg) and atropine (0.5 mg/kg), but were abolished by hexamethonium (2 mg/min, 10-25 mg) and pancuronium (0.1-0.3 mg/kg) in both groups. In N group, repetitive stimulation (10-20 Hz) of HGN increased activities of the rhabdosphincter when the bladder was empty, but not when the bladder was full enough to trigger the vesicourethral relaxation reflex.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗