Effects Of Pudendal Nerve Stimulation Research Articles

Bladder underactivity induced by prolonged pudendal afferent activity in cats.

The purpose of this study was to determine the effects of pudendal nerve stimulation (PNS) on reflex bladder activity and develop an animal model of underactive bladder (UAB). In six anesthetized cats, a bladder catheter was inserted via the urethra to infuse saline and measure pressure. A cuff electrode was implanted on the pudendal nerve. After determination of the threshold intensity (T) for PNS to induce an anal twitch, PNS (5 Hz, 0.2 ms, 2 T or 4 T) was applied during cystometrograms (CMGs). PNS (4-6 T) of 30-min duration was then applied repeatedly until bladder underactivity was produced. Following stimulation, control CMGs were performed over 1.5-2 h to determine the duration of bladder underactivity. When applied during CMGs, PNS (2 T and 4 T) significantly (P < 0.05) increased bladder capacity while PNS at 4 T also significantly (P < 0.05) reduced bladder contraction amplitude, duration, and area under contraction curve. Repeated application of 30-min PNS for a cumulative period of 3-8 h produced bladder underactivity exhibiting a significantly (P < 0.05) increased bladder capacity (173 ± 14% of control) and a significantly (P < 0.05) reduced contraction amplitude (50 ± 7% of control). The bladder underactivity lasted more than 1.5-2 h after termination of the prolonged PNS. These results provide basic science evidence supporting the proposal that abnormal afferent activity from external urethral/anal sphincter could produce central inhibition that underlies nonobstructive urinary retention (NOUR) in Fowler's syndrome. This cat model of UAB may be useful to investigate the mechanism by which sacral neuromodulation reverses NOUR in Fowler's syndrome.

Neuromodulatory effects of pudendal nerve stimulation on bladder hypersensitivity are present in opioid-pretreated rats

Background and objectivesBilateral electrical pudendal nerve stimulation (bPNS) reduces bladder hypersensitivity in rat models and anecdotally reduces pain in humans with pelvic pain of urologic origin. Concomitant opioids are known...

Pudendal Nerve Stimulation and Block by a Wireless-Controlled Implantable Stimulator in Cats

The study aims to determine the functionality of a wireless-controlled implantable stimulator designed for stimulation and block of the pudendal nerve. In five cats under α-chloralose anesthesia, the stimulator was implanted underneath the skin on the left side in the lower back along the sacral spine. Two tripolar cuff electrodes were implanted bilaterally on the pudendal nerves in addition to one bipolar cuff electrode that was implanted on the left side central to the tripolar cuff electrode. The stimulator provided high-frequency (5-20 kHz) biphasic stimulation waveforms to the two tripolar electrodes and low-frequency (1-100 Hz) rectangular pulses to the bipolar electrode. Bladder and urethral pressures were measured to determine the effects of pudendal nerve stimulation (PNS) or block. The maximal (70-100 cmH2O) urethral pressure generated by 20-Hz PNS applied via the bipolar electrode was completely eliminated by the pudendal nerve block induced by the high-frequency stimulation (6-15 kHz, 6-10 V) applied via the two tripolar electrodes. In a partially filled bladder, 20-30 Hz PNS (2-8 V, 0.2 ms) but not 5 Hz stimulation applied via the bipolar electrode elicited a large sustained bladder contraction (45.9 ± 13.4 to 52.0 ± 22 cmH2O). During cystometry, the 5 Hz PNS significantly (p < 0.05) increased bladder capacity to 176.5 ± 27.1% of control capacity. The wireless-controlled implantable stimulator successfully generated the required waveforms for stimulation and block of pudendal nerve, which will be useful for restoring bladder functions after spinal cord injury.

Early low-frequency stimulation of the pudendal nerve can inhibit detrusor overactivity and delay progress of bladder fibrosis in dogs with spinal cord injuries

To determine the inhibitory effects of pudendal nerve stimulation (5 Hz) on bladder overactivity at the early stage of spinal cord injury (SCI) in dogs, and to explore the possible effects on delayed progression of bladder fibrosis after SCI. The study was performed using six dogs with spinal cord transection at the T9–T10 level. Group 1 (three dogs) under went low-frequency electrical stimulation of the pudendal nerve 1 day after spinal cord transection. Group 2 (three dogs) underwent only spinal cord transection. All dogs underwent urodynamic examination at 1 and 3 months after SCI. The bladders were removed for histological examination of fibrosis at 3 months after SCI. Bladder capacity and compliance were significantly increased (P<0.05) by pudendal nerve stimulation in group 1 when compared with group 2 at 1 and 3 months after SCI. Non-voiding contractions (NVCs) were inhibited in group 1 compared with group 2. Collagen fibers were significantly increased and elastic fibers were significantly decreased (P<0.05) in group 2 when compared with group 1. Early low-frequency pudendal nerve stimulation can inhibit detrusor overactivity (DO), increase bladder capacity and delay the progression of bladder fibrosis.

Effects of pudendal nerve stimulation with different frequency on bladder dysfunction in spinal cord injury dogs

Objective To determine the effects of pudendal ncrve stimulation with different frequency(5 Hz,20 Hz) on bladder dysfunction dogs after spinal cord injury.Methods The study was done in 4 dogs which chronic spinal cord transection at T9-T10 level.All the dogs underwent electrical stimulation of pudendal nerve (5 Hz,20 Hz).Then,bladder capacity,compliance,non-voiding contraction number (NVC) and voiding efficiency before and during stimulation were compared.Results The bladder capacity and the compliance was increased ( 58.9 ± 17.4) ％ and (53.1 ± 4.9 ) ％ ( P ＜ 0.05 ) by pudendal nerve stimulation with low frequency (5 Hz).Detrusor overactivity can be inhibited and the NVC decreased from 1.7 ± 1.3 to 0.9 ± 1.1.Pudendal nerve stimulation with medium frequency ( 20 Hz) can induce bladder contraction and increased voiding efficiency from (5.8 ± 1.0) ％ to ( 16.3 ± 2.6 ) ％ ( P ＜0.05).Conclusions Pudendal nerve stimulation with low frequency can inhibit detrusor overactivity and increase the bladder capacity and compliance in spinal cord injury dogs.Pudendal nerve stimulation with medium frequency can induce bladder contraction and increased voiding efficicncy. Key words: Bladder; Spinal cord injury; Pudendal nerve stimulation; Dogs; Urodynamics

The Inhibitory Effects of Pudendal Nerve Stimulation on Bladder Overactivity in Spinal Cord Injury Dogs: Is Early Stimulation Necessary?

To determine the inhibitory effects of pudendal nerve stimulation (5 Hz) on bladder overactivity at early and late stages of spinal cord injury in dogs. The study was performed in eight dogs with chronic spinal cord transection at the T9-T10 level. Group 1 (four dogs) underwent electrical stimulation of pudendal nerve one month after spinal cord transection. Group 2 (four dogs) underwent stimulation six months after spinal cord transection. The bladders were removed for histological examination of fibrosis after the stimulation. The bladder capacity and the compliance were significantly increased (p < 0.05) by pudendal nerve stimulation in group 1, but not in group 2. The nonvoiding contractions were inhibited in both groups by electrical stimulation. Collagen fiber was increased, while elastic fiber was significantly decreased (p < 0.05) in group 2 when compared with group 1. Pudendal nerve stimulation can increase the bladder capacity and compliance only during the early period before the bladder wall becomes fibrosit and can inhibit the nonvoiding contraction during two stages.

Pudendal-to-bladder reflex in chronic spinal-cord-injured cats

The effects of pudendal nerve stimulation on reflex bladder activity were investigated in cats with chronic spinal cord injury (6–12 months) under α-chloralose anesthesia. Electrical stimulation of the pudendal nerve on one side at different frequencies and intensities induced either inhibitory or excitatory effects on bladder activity. The inhibitory effect peaked at a stimulation frequency of 3 Hz and gradually decreased at lower or higher frequencies. The inhibitory effect could occur at stimulation intensities between 0.3 and 1 V (pulse width 0.1 ms) and increased at intensities up to 10 V. Stimulation of the central end of transected pudendal nerve also inhibited bladder activity, indicating that afferent axons in pudendal nerve are involved. Nerve transections also showed that both hypogastric and pelvic nerves might be involved in the inhibitory pudendal-to-bladder spinal reflex. Pudendal nerve stimulation at 20 Hz and at the same intensities (1–10 V) elicited a bladder excitatory response. Although this excitatory effect could not sustain a long lasting bladder contraction at small bladder volumes, it did induce continuous rhythmic bladder contractions at large bladder volumes. This study indicated the possibility of developing a neuroprosthetic device based on pudendal nerve electrical stimulation to restore micturition function after spinal cord injury.

Effects of pudendal nerve stimulation on neurons in pericruciate cerebral cortex of male domestic cats

The pudendal nerve, which innervates the anogenital region, has been implicated in micturition and in male sexual behavior. Electrical stimulation of this nerve in chloralose-anesthetized male cats evoked activity thoughout the anterior and posterior sigmoid, anterior ectosylvian, and anterior marginal gyri. The influence was bilateral at every site examined; no contralateral focus was found on the dorsum of the anterior hemisphere. The influence was not only bilateral, but of the same magnitude and nearly the same latency in both hemispheres. Furthermore, the gross potentials evoked by stimulation of either pudendal nerve were similar in configuration and amplitude to those evoked by ipsilateral forepaw and ipsilateral hind paw stimulation. Single-neuron recordings from four sites—medial and lateral precruciate and postcruciate—revealed that 17% of the sa neurons, 55% of the sb neurons, and 98% of the m neurons could be excited by pudendal nerve stimulation. Of the neurons tested and found to respond to the contralateral pudendal nerve, fully 98% also responded to the ipsilateral pudendal nerve. Some sa neurons that failed to respond to pudendal nerve stimulation were rendered less excitable to paw stimulation by conditioning stimulation of that nerve. These same sa neurons were also rendered less excitable to paw stimulation by conditioning stimulation of any of the other (nonexcitatory) paws. The property of coadunate behavior among the m neurons clearly included their responses to pudendal nerve stimulation. The numerous sensory inputs to m neurons—cutaneous, visual, auditory, vestibular, thoracic and pelvic splanchnic, and now pudendal—arrive via markedly different pathways, suggesting that the mechanism underlying coadunate behavior is to be found within the cerebral cortex itself. It is argued that in the intact, behaving animal these disparate sensory influences onto cerebral m neurons function to modulate the excitability of these neurons, their effective driving input arriving via the local sa (small-field) neurons that reside in layers II and III. It is further argued that some of these m neurons act to depress the excitability of certain sa neurons in their neighborhood.