Bladder-wall and pelvic-plexus stimulation with model microstimulators: Preliminary observations

Walter, James S.; FitzGerald, Mary P.; Wheeler, John S.; Orris, Bradley; McDonnell, Allison; Wurster, Robert D.

doi:10.1682/jrrd.2004.01.0014

Cited by 13 publications

(4 citation statements)

References 23 publications

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“…The voiding efficiency in intact anesthetized rats before any nerve transections or electrical stimulation was only ∼70%, which is lower than the ∼98-99% voiding efficiency measured in conscious animals (Yaksh et al 1986, Walter et al 2005. Similar low voiding efficiencies were reported in other studies (Cheng and de Groat 2004, Cruz and Downie 2005, Peng et al 2006, and presumably resulted from the urethane anesthesia inhibiting reflex bladder contractions and reducing the contraction pressure during micturition (Yaksh et al 1986).…”

Section: Discussionsupporting

confidence: 55%

Improved bladder emptying in urinary retention by electrical stimulation of pudendal afferents

et al. 2008

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Urinary retention is the inability to empty the bladder completely, and may result from bladder hypocontractility, increases in outlet resistance, or both. Chronic urinary retention can lead to several urological complications and is often refractory to pharmacologic, behavioral, and surgical treatments. We sought to determine whether electrical stimulation of sensory fibers in the pudendal nerve could engage an augmenting reflex and thereby improve bladder emptying in an animal model of urinary retention. We measured the efficiency of bladder emptying with and without concomitant electrical stimulation of pudendal nerve afferents in urethane anesthetized rats. Voiding efficiency (VE=voided volume/initial volume) was reduced from 72±7% to 29±7% following unilateral transection of the sensory branch of the pudendal nerve (UST) and from 70±5% to 18±4% following bilateral transection (BST). Unilateral electrical stimulation of the proximal transected sensory pudendal nerve during distention-evoked voiding contractions significantly improved VE. Low intensity stimulation at frequencies of 1-50 Hz increased VE to 40-51% following UST and to 39-49% following BST, while high intensity stimulation was ineffective at increasing VE. The increase in VE was mediated by increases in the duration of distention-evoked voiding bladder contractions, rather than increases in contraction amplitude. These results are consistent with an essential role for pudendal sensory feedback in efficient bladder emptying, and raise the possibility that electrical activation of pudendal nerve afferents may provide a new approach to restore efficient bladder emptying in persons with urinary retention.

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Section: Discussionsupporting

confidence: 55%

Improved bladder emptying in urinary retention by electrical stimulation of pudendal afferents

et al. 2008

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“…Diabetic cystopathy is characterized by typical symptoms including an impaired sensation of bladder fullness, increased bladder capacity, decreased bladder contractility, detrusor sphincter dyssynergia (DSD), and elevated postvoid residual urine volumes [5][6][7]. Clinically, chronic diabetes-induced urinary retention may increase bladder pressure and vesicourethral reflux, and even cause renal failure.…”

Section: Introductionmentioning

confidence: 99%

Chronic pudendal neuromodulation using an implantable microstimulator improves voiding function in diabetic rats

et al. 2016

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Abtract Objective. Few studies have investigated the feasibility of using chronic pudendal neuromodulation for improving voiding function in patients with diabetes who are also experiencing urinary retention. The present study investigated the effects of chronic electrical stimulation (ES) of the sensory branch of the pudendal nerve on voiding function in diabetic rats. Approach. A custom-made implantable microstimulation system was designed and manufactured for chronic implantation in normal control (NC) and diabetic rats. After three or six weeks of pudendal neuromodulation, the intravesical pressure, external urethral sphincter electromyograms (EUS-EMGs), and urine flow rate (UFR) of all rats were simultaneously recorded to assess the effects of chronic pudendal ES on voiding function. Morphological changes in pudendal axons were assessed through hematoxylin and eosin (H&E) staining. Results. Abnormal cystometric measurements, including an increased volume threshold, contraction amplitude, and residual volume (RV) as well as a decreased burst period (BP) indicated voiding dysfunction in the diabetic rats with sham ES for three or six weeks. However, real ES for three or six weeks reversed these abnormal results; these parameters became similar to those of the NC rats and, consequently, voiding efficiency (VE) increased significantly from 17%–45% to 51%–57%. The cross-sectional area and axonal density of the pudendal nerve decreased in all the diabetic rats with sham ES for six weeks; however, these values increased significantly after real ES for six weeks. Significance. This study demonstrated the feasibility of using chronic pudendal neuromodulation for improving voiding function in diabetic rats. These results may facilitate the development of an advanced neural prosthesis for restoring bladder function in clinical settings.

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“…We reported similar stimulating parameters for direct bladder stimulation in chronic cat models [19][20][21][22][23]. However, the induced peak pressures in those animals were higher [19][20][22][23]. The higher pressures may have resulted from studies without anesthesia (not needed after SCI) and a model with bladder wall hypertrophy.…”

Section: Discussionmentioning

confidence: 83%

Effective methods of pelvic plexus nerve and bladder stimulation in anesthetized animal model

Bresler

Walter²,

Jahoda³

et al. 2008

JRRD

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Abstract-Urinary retention is a serious urological problem associated with spinal cord injuries (SCIs) and other pelvic disorders. Effective methods of pelvic nerve stimulation were investigated for this problem. Following anesthesia in five dogs, the bladder was surgically exposed. Bladder and anal sphincter pressures were recorded. Testing was first conducted with probe electrodes. Barb electrodes were then implanted with a needle near the pelvic plexus nerves and the bladder wall. We tested different electrode arrangements and stimulating parameters to induce bladder contractions without skeletal muscle stimulation. The pelvic plexus nerves near the bladder were identified, and the barb electrodes were effectively implanted. Stimulation with bipolar and bilateral electrodes induced pressures over 30 cmH 2 O without skeletal muscle activation. Common stimulation parameters were 40 pps, 400 microseconds pulse duration, and 15 to 25 mA stimulating current applied for 3 s. Effective electrode implantation methods were shown. Also identified were electrode arrangements and stimulating parameters that induced strong bladder contractions without skeletal muscle activation. However, voiding studies were not conducted. Further studies with barb electrodes are warranted, and these methods may have applications for bladder stimulation following SCI.

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Bladder-wall and pelvic-plexus stimulation with model microstimulators: Preliminary observations

Cited by 13 publications

References 23 publications

Improved bladder emptying in urinary retention by electrical stimulation of pudendal afferents

Improved bladder emptying in urinary retention by electrical stimulation of pudendal afferents

Chronic pudendal neuromodulation using an implantable microstimulator improves voiding function in diabetic rats

Effective methods of pelvic plexus nerve and bladder stimulation in anesthetized animal model

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