Feasibility of Real-Time Conditional Sacral Neuromodulation Using Wireless Bladder Pressure Sensor (original) (raw)
Related papers
Effects of Acute Sacral Neuromodulation at Different Pulse Widths on Bladder Overactivity in Pigs
International Neurourology Journal, 2019
Sacral nerve stimulation has been used to treat overactive bladder. This study evaluated the effects of stimulation using different pulse widths on the inhibition of bladder overactivity by sacral nerve stimulation (SNM) in pigs. Methods: Implant-driven stimulators were used to stimulate the S3 spinal nerve in 7 pigs. Cystometry was performed by infusing normal saline (NS) or acetic acid (AA). SNM at pulse widths of 64 µsec to 624 µsec was conducted at the intensity threshold at which observable perianal and/or tail movement was induced. Multiple cystometrograms were performed to determine the effects of different pulse widths on the micturition reflex. Results: AA-induced bladder overactivity reduced the bladder capacity to 46.9% ± 7.1% of the NS control level (P < 0.05). During AA infusion, SNM at 64 µsec, 204 µsec, and 624 µsec increased the bladder capacity to 126.1% ± 6.9%, 129.5% ± 7.3%, and 140.1% ± 7.6% of the AA control level (P < 0.05). No significant differences were found among the results obtained using pulse widths of 64 µsec, 204 µsec, and 624 µsec (P > 0.05). The actual intensity threshold varied from 0.7 to 8 V. The mean intensity threshold (T visual) for pulse widths of 64 µs, 204 µs, and 624 µs were 5.64 ± 0.76 V, 3.11 ± 0.48 V, and 2.52 ± 0.49 V. T visual for pulse widths of 64 µsec was larger than the other two T visual for pulse widths of 204 µsec and 624 µsec (P < 0.05). No significant differences were found among the T visual for pulse widths of 204 µsec and 624 µsec (P > 0.05). Conclusions: This study indicated that different pulse widths could play a role in inhibiting bladder overactivity. It is not yet certain which pulse widths increased bladder capacity compared with AA levels, to minimize energy consumption and maintain patient comfort during stimulation, 204 µsec may be an appropriate pulse width for SNM.
2020
Overactive bladder patients suffer from a frequent and uncontrollable urge to urinate, which can lead to a poor quality of life. Current sacral neuromodulation therapy uses open-loop electrical stimulation to alleviate symptoms, which limits battery life and can lead to neural habituation. In this study, we aim to improve therapy by developing a conditional stimulation paradigm using neural recordings from dorsal root ganglia (DRG) as sensory feedback. Experiments were performed in 5 non-survival, anesthetized felines, in which the sacral-level DRG and spinal roots were exposed bilaterally. A bipolar cuff electrode was placed on a S1 root distal to the DRG for stimulation. Microelectrode arrays were implanted in the same or opposite S1 and/or S2 DRG. We implemented a Kalman filter-based algorithm to estimate the bladder pressure in real-time using DRG neural recordings. The Medtronic Summit Research Development Kit was used to control sacral root stimulation when the algorithm detected an increase in bladder pressure. Closed-loop neuromodulation was performed during continuous cystometry and compared to bladder fills with continuous and no stimulation. Overall, closed-loop stimulation with DRG sensory feedback increased bladder capacity by 13.8% over no stimulation (p < 0.001). While there was no statistical difference in bladder capacity between closed-loop and continuous stimulation (p = 0.80), closed-loop stimulation reduced stimulation time by 57.7%. High-confidence bladder single units had a reduced sensitivity during stimulation, with lower linear trendline fits and higher pressure thresholds for firing observed during stimulation trials. This study demonstrates the utility of decoding bladder pressure from neural activity for closed-loop control of sacral neuromodulation. An underlying mechanism for sacral neuromodulation may be a reduction in bladder sensory neuron activity during stimulation. Real-time validation during behavioral studies is necessary prior to clinical translation of closed-loop sacral neuromodulation.
2014
Although sacral anterior root neuromodulation (SARN) has proven to be effective in patients with neurogenic bladder, it is not widely accepted due to the need to conduct a dorsal rhizotomy, and commercially available SARN devices are not usually equipped with a closed-loop controller for the automatic regulation of bladder functions. Therefore, there is still a need for a more effective electrical neuromodulation scheme to restore bladder function. Intravesical pressure (IVP) is the major biosignal that reflects the state of bladder conditions. The present study develops a closed-loop control strategy for improving bladder emptying and verifies its performance using animal experiments. Two channel outputs of electrical currents triggered by IVP-feedback signals were set to automatically regulate a rat's pudendal nerve for selective nerve stimulation and blocking. Under this experimental design, a series of in vivo animal experiments were conducted on anesthetized rats, including the computational characterization of biosignals, the development of an intermittent high-frequency blocking current waveform for blocking the nerve, and verification of the control strategy. Results show that the IVP-feedback control strategy for dual-channel pudendal neuromodulation performed well in animal experiments and could be utilized to selectively stimulate and block the pudendal nerve to augment bladder contraction and restore external urethral sphincter bursting activity to improve bladder emptying. This study demonstrates the feasibility of the IVP-based feedback-control strategy with animal experiments. The results could provide a basis for developing a sophisticated neural prosthesis for restoring bladder function in clinical use or for neurophysiological study.
Neuromodulation for Neurogenic Bladder
Although neuromodulation is well established for the treatment of non-neurogenic lower urinary tract symptoms, recent literature supports its use in the patient having LUTS associated with a neurologic condition. Sacral neuromodulation, in particular, may see new use as a modality to facilitate neurologic remodeling in spinal cord injured patients as well as children. As a therapeutic option, sacral neuromodulation and dorsal genital nerve stimulation may one day become more effective and more efficient utilizing the concept of closed-loop feedback, where electro-neurogram and bladder pressure data are incorporated into stimulation routines. In addition, some older therapies are reviewed that have recently demonstrated success in this patient population.
2011
Hypothesis / aims of study A novel, non-invasive PMNS has been developed for the treatment of OAB syndrome. The PMNS transmits a transdermal amplitude-modulated signal (TAMS) wirelessly, through a patch applied to the skin. The primary objective of this study was to evaluate the efficacy of the PMNS treatment in reducing urgency urinary incontinence and on patient-reported symptoms, life impact, and satisfaction using validated, disease-specific Patient Reported Outcome (PRO) measures. Differences in efficacy, depending on whether the non-invasive patch was positioned by the investigator (Investigator Placement Group, IPG) or the subject (Subject Placement Group, SPG), were also determined. Safety of PMNS treatment was assessed throughout the study.
European Urology Supplements, 2018
The RELAX-OAB study is designed to confirm the safety, efficacy, and technical performance of the Axonics r-SNM System, a miniaturized, rechargeable SNM system approved in Europe and Canada for the treatment of bladder and bowel dysfunction. The purpose of this article is to describe study subjects' ability to charge the rechargeable neurostimulator and to document their neurostimulator program settings and recharge interval over time. Methods: Fifty-one OAB patients were implanted in a single-stage procedure. These results represent the 3-month charging experience for 48 subjects who completed the 3-month follow-up. Recharge intervals were estimated using therapy stimulation settings and subject experience was evaluated using questionnaires. Results: Forty-seven of forty-eight (98%) subjects were able to successfully charge their device prior to follow-up within 1-month post-implant. At 3-month post-implant, 98% of subjects were able to charge prior to their follow-up visit. Average stimulation amplitude across all subjects was 1.8 mA (±1.1 mA). A total of 69% of subjects had ≥14-day recharge intervals (time between charging) and 98% of subjects had ≥7-day recharge interval. No charging related adverse events occurred. Conclusions: Study subjects were able to charge the Axonics r-SNM System and stimulation settings provided 2 weeks of therapy between recharging for most subjects. Subject satisfaction indicates that subjects are satisfied with rechargeable SNM therapy.
Review Article Pelvic Electrical Neuromodulation for the Treatment of Overactive Bladder Symptoms
2013
Copyright © 2011 Tariq F. Al-Shaiji et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Overactive bladder syndrome negatively affects the daily life of many people. First-line conservative treatments, such as antimuscarinics, do not always lead to sufficient improvement of the complaints and/or are often associated with disabling adverse effects leading to treatment failure. Electrical stimulation of the sacral nerves has emerged as an alternative and attractive treatment for refractory cases of bladder overactivity. Few theories attempted to explain its mechanism of action which remains elusive. It involves percutaneous posterior tibial nerve stimulation and more commonly sacral neuromodulation. For the latter, temporary sacral nerve stimulation is the first step. If the test stimulation is successful, a permanent...
Medical devices (Auckland, N.Z.), 2017
This review describes the evidence from established and experimental therapies that use electrical nerve stimulation to treat lower urinary tract dysfunction. Clinical studies on established treatments such as percutaneous posterior tibial nerve stimulation (P-PTNS), transcutaneous electrical nerve stimulation (TENS), sacral nerve stimulation (SNS) and sacral anterior root stimulation (SARS) are evaluated. In addition, clinical evidence from experimental therapies such as dorsal genital nerve (DGN) stimulation, pudendal nerve stimulation, magnetic nerve stimulation and ankle implants for tibial nerve stimulation are evaluated. SNS and P-PTNS have been investigated with high-quality studies that have shown proven efficacy for the treatment for overactive bladder (OAB). SARS has proven evidence-based efficacy in spinal cord patients and increases the quality of life. TENS seems inferior to other OAB treatments such as SNS and P-PTNS but is noninvasive and applicable for ambulant thera...
Neuromodulation in Urology: Current Trends and Future Applications
Neuromodulation and Neurostimulation [Working Title]
Urological applications of neuromodulation and neurostimulation are among the most evolving fields for these technologies. First approved for management of refractory urge incontinence, different modalities of neuromodulation and stimulation have been tested, applied and verified for a vast spectrum of voiding and pelvic floor dysfunction disorders. The modalities of delivering this treatment have also evolved in the last three decades, with a focus on sacral neuromodulation. The experimental and established "off-label" applications of neuromodulation have also encompassed chronic pelvic pain disorders, including chronic prostatitis and bladder pain syndrome, among others. In this chapter, we discuss all the hypothesized theories suggested on how this technology provides therapeutic potential for a number of chronic and debilitating urological conditions, the modes of delivery be it anterior, sacral, and posterior tibial to name a few, and the evolving and future applications.