Real-Time Changes in Brain Activity during Sacral Neuromodulation for Overactive Bladder

Gill, Bradley C.; Pizarro-Berdichevsky, Javier; Bhattacharyya, Pallab K.; Brink, Thaddeus S.; Marks, Brian; Quirouet, Adrienne; Vasavada, Sandip P.; Jones, Stephen E.; Goldman, Howard B.

doi:10.1016/j.juro.2017.06.074

Cited by 55 publications

(53 citation statements)

References 24 publications

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“…It has been postulated that the clinically observed contraction of the PFM upon stimulation of the sacral spinal nerves, represented by the bellows response, is correlated to reflex responses (R2 and R3 EPFMR) mediated by afferent input to the spinal cord 5,6 . This observation has served as one of the key findings in the generation or confirmation of hypotheses on the mechanism of action of SNM 7‐9 …”

Section: Introductionmentioning

confidence: 98%

Neural pathway of bellows response during SNM treatment revisited: Conclusive evidence for direct efferent motor response

Vaganée

Voorham

Panicker

et al. 2020

Neurourology and Urodynamics

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Background In sacral neuromodulation (SNM) patients, it is thought the bellows response elicited upon sacral spinal nerve stimulation is reflex‐mediated. Therefore the mechanism of action of SNM is considered to be at the spinal or supraspinal level. These ideas need to be challenged. Objective To identify the neural pathway of the bellows response upon sacral spinal nerve stimulation. Design, Setting, and Participants Single tertiary center, prospective study (December 2017‐June 2019) including 29 patients with overactive bladder refractory to first‐line treatment. Intervention Recording of the pelvic floor muscle response (PFMR) using a camcorder and electromyography (EMG) (intravaginal probe and concentric needles) upon increasing stimulation during lead or implantable pulse generator placement. Outcome Measurements and Statistical Analysis The lowest stimulation intensity needed to elicit a visual PFMR and electrical PFMR was determined. Electrical PFMRs were subdivided according to their latency. Outcome: the association between visual and electrical PFMRs. Statistical analyses were performed using the weighted kappa coefficient. Results Three different electrical PFMRs could be identified by surface and needle EMG, corresponding with a direct efferent motor response (R1), oligosynaptic (R2), and polysynaptic (R3) afferent reflex response. Only the R1 electrical PFMR was perfectly associated with the visual PFMR (κ = 0.900). Conclusions The visual PFMRs upon sacral spinal nerve stimulation are direct efferent motor responses. A reopening of the discussion on the mechanism of action of SNM is possibly justified.

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Section: Introductionmentioning

confidence: 98%

Neural pathway of bellows response during SNM treatment revisited: Conclusive evidence for direct efferent motor response

Vaganée

Voorham

Panicker

et al. 2020

Neurourology and Urodynamics

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show abstract

“…The authors reported activation of the right inferior frontal gyrus independent of stimulation amplitude. Increasing the stimulation amplitude activated several brain areas, whereas subsensory stimulation was noted to only reduce activity in the pons and periaqueductal grey matter [34]. These two studies indicate that SNS influences brain activity, that neuromodulation takes place and that the stimulation intensity has an effect on the amount of neuromodulation.…”

Section: Discussionmentioning

confidence: 78%

Improved longevity and efficacy of sacral nerve stimulation by simple adjustments at follow‐up

et al. 2019

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Aim Sacral nerve stimulation (SNS) for faecal incontinence (FI) at subsensory amplitudes as low as 50% of the sensory threshold has been found to be effective at 3 months’ follow‐up. Furthermore, alternative pacemaker settings may improve functional outcome in patients with suboptimal treatment efficacy. In this work we aim to explore if sub‐sensory stimulation as low as 50% of sensory threshold is effective at 1‐year follow‐up. We also aimed to investigate if 31 Hz (frequency) or 90 µs (pulse width) stimulation improved treatment efficacy in dissatisfied patients. Method All patients in whom the stimulation was effective in controlling FI (satisfied group) were encouraged to have the stimulation amplitude reduced. Those in whom the device was less effective (dissatisfied group) were offered alternative frequency settings or pulse width (31 Hz or 90 µs). Patients were follow‐up after 12 months and evaluated by a visual analogue scale (VAS) for patient satisfaction, the Cleveland Clinic Continence Score (CCCS), Rockwood Faecal Incontinence Quality of Life Scale (QoL) and a bowel habit diary. Results Two hundred and nineteen patients were contacted, with a response rate of 71% (n = 155). Those who were successfully contacted comprised 110 (71%) patients classed as satisfied and 45 (29%) as dissatisfied. Seventy‐five (68%) of the satisfied patients agreed to have their stimulation amplitude reduced. At 1‐year follow‐up the median amplitude had reduced from 1.5 V [interquartile range (IQR) 0.85–2.0 V] to 0.75 V (IQR 0.45–1.4 V) (P‐value < 0.001) representing an overall reduction of 39% (6.6–62.5%). There were no significant differences in VAS, CCCS or QoL despite subsensory stimulation at 1‐year follow‐up. In 28% of the dissatisfied patients alternative pacemaker settings improved VAS to satisfactory levels. Conclusion Subsensory stimulation is as effective as stimulation at or above the sensory threshold. High‐frequency stimulation (31 Hz) can improve functional outcome in patients with loss of efficacy.

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“…The mechanisms underlying the effectiveness of neuromodulation strategies to control bladder function are not fully understood. Recent thinking is that activation of afferents by low‐frequency stimulation results in a change in bladder perception threshold and an increased bladder capacity, almost certainly mediated via a central mechanism . The effectiveness of high‐frequency stimulation is also thought to be due to activation of afferent fibers, albeit likely via engagement of a different central mechanism .…”

Section: Discussionmentioning

confidence: 99%

Suppression of Urinary Voiding “on Demand” by High-Frequency Stimulation of the S1 Sacral Nerve Root in Anesthetized Rats

Brouillard

Crook

Lovick

2019

Neuromodulation: Technology at the Neural Interface

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Objectives: High-frequency (kHz) stimulation of preganglionic pelvic nerve afferents can inhibit voiding in both anesthetized and conscious rats. The afferents travel via the S1 sacral nerve root, which is easier to access than the distal pelvic nerve fibers within the abdominal cavity. We therefore investigated whether voiding could be inhibited by high-frequency stimulation at S1 and how this compared to distal pelvic nerve stimulation.Methods: Urethane-anesthetized rats were instrumented to record bladder pressure and abdominal wall electromyogram and to stimulate the distal preganglionic pelvic nerve bundle and S1 sacral root. Saline was infused continuously into the bladder to evoke repeated voiding. Stimulation was initiated within 1-2 sec of the onset of the steep rise in bladder pressure signaling an imminent void.Results: In six rats, stimulation of the distal pelvic nerve bundle (1-3 kHz sinusoidal waveform 1 mA, 60 sec) supressed the occurrence of an imminent void. Voiding resumed within 70 AE 13.0 sec (mean AE SEM) of stopping stimulation. Stimulation (using the same parameters) of the S1 root at the level of the sacral foramen suppressed voiding for the entire stimulation period in three rats and deferred voiding for 35-56 sec (mean 44.0 AE 3.2 sec) in the remaining three. Stimulation at either site when the bladder was approximately half full, as estimated from previous intervoid intervals, had no effect on voiding.Conclusions: This preliminary study provides proof-of-concept for the sacral root as an accessible target for high-frequency stimulation that may be developed as an "on demand" neuromodulation paradigm to suppress unwanted urinary voids.

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Real-Time Changes in Brain Activity during Sacral Neuromodulation for Overactive Bladder

Abstract: Functional magnetic resonance imaging confirmed that sacral neuromodulation influences brain activity in women with overactive bladder who responded to therapy. These changes varied with stimulus intensity.

Cited by 55 publications

References 24 publications

Neural pathway of bellows response during SNM treatment revisited: Conclusive evidence for direct efferent motor response

Neural pathway of bellows response during SNM treatment revisited: Conclusive evidence for direct efferent motor response

Improved longevity and efficacy of sacral nerve stimulation by simple adjustments at follow‐up

Suppression of Urinary Voiding “on Demand” by High-Frequency Stimulation of the S1 Sacral Nerve Root in Anesthetized Rats

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