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Doelman AW, Streijger F, Majerus SJA, Damaser MS, Kwon BK. Assessing Neurogenic Lower Urinary Tract Dysfunction after Spinal Cord Injury: Animal Models in Preclinical Neuro-Urology Research. Biomedicines 2023; 11:1539. [PMID: 37371634 DOI: 10.3390/biomedicines11061539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 05/20/2023] [Accepted: 05/21/2023] [Indexed: 06/29/2023] Open
Abstract
Neurogenic bladder dysfunction is a condition that affects both bladder storage and voiding function and remains one of the leading causes of morbidity after spinal cord injury (SCI). The vast majority of individuals with severe SCI develop neurogenic lower urinary tract dysfunction (NLUTD), with symptoms ranging from neurogenic detrusor overactivity, detrusor sphincter dyssynergia, or sphincter underactivity depending on the location and extent of the spinal lesion. Animal models are critical to our fundamental understanding of lower urinary tract function and its dysfunction after SCI, in addition to providing a platform for the assessment of potential therapies. Given the need to develop and evaluate novel assessment tools, as well as therapeutic approaches in animal models of SCI prior to human translation, urodynamics assessment techniques have been implemented to measure NLUTD function in a variety of animals, including rats, mice, cats, dogs and pigs. In this narrative review, we summarize the literature on the use of animal models for cystometry testing in the assessment of SCI-related NLUTD. We also discuss the advantages and disadvantages of various animal models, and opportunities for future research.
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Affiliation(s)
- Adam W Doelman
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Femke Streijger
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Steve J A Majerus
- Department of Electrical, Computer and Systems Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
- Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106, USA
| | - Margot S Damaser
- Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106, USA
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Brian K Kwon
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
- Department of Orthopaedics, Vancouver Spine Surgery Institute, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
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Vaginal Lubrication and Pressure Increase Induced by Pudendal Nerve Stimulation in Cats. J Sex Med 2022; 19:1517-1523. [PMID: 36057523 DOI: 10.1016/j.jsxm.2022.07.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 06/25/2022] [Accepted: 07/31/2022] [Indexed: 11/21/2022]
Abstract
BACKGROUND Vaginal lubrication and contractions are among the top difficulties affecting sexual intercourse in women after spinal cord injury. AIM This study aimed at determining if pudendal nerve stimulation (PNS) can improve vaginal lubrication and induce increases in vaginal pressure. METHODS In anesthetized cats, a small piece of cotton was inserted into the vagina for 10 minutes with or without PNS to measure vaginal wetness by the weight increase of the vaginal cotton. Then, a small balloon catheter was inserted into the vagina to measure the pressure increase induced by PNS. Intensity response of the vagina to PNS (30 Hz, 0.2 ms, 5 seconds) was determined at 1-4 times of intensity threshold (T) for PNS to induce an observable vaginal pressure increase. Frequency response was determined at 2T intensity in a range of PNS frequencies (5-50 Hz). Finally, fatigue in vaginal pressure was determined by applying PNS (30 Hz, 2T) either continuously or intermittently (5 seconds on and 5 seconds off) for 4 minutes. OUTCOMES The effectiveness of PNS in increasing vaginal wetness and pressure is evaluated. RESULTS PNS significantly (P = .0327) increased the measurement of vaginal wetness from 15.8 ± 3.8 mg during control without stimulation to 32.4 ± 4.7 mg after stimulation. Vaginal pressure increased as PNS intensity or frequency increased. PNS (30 Hz, 2T) induced vaginal pressure increase ≥80% of the maximal response. Intermittent PNS induced significantly (P = .0354) smaller fatigue (45.6 ± 3.7%) in vaginal pressure than continuous PNS (69.1 ± 3.0%) during the 4-minute stimulation. CLINICAL TRANSLATION This study raises the possibility of developing a novel pudendal neuromodulation device to improve female sexual function after spinal cord injury. STRENGTHS & LIMITATIONS This study provides preclinical data supporting the development of a novel pudendal neuromodulation device. The limitation includes the lack of chemical analysis of the vaginal secretion. CONCLUSION PNS can improve vaginal lubrication and induce increases in vaginal pressure.
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Ali MU, Fong KNK, Kannan P, Bello UM, Kranz GS. Effects of nonsurgical, minimally or noninvasive therapies for urinary incontinence due to neurogenic bladder: a systematic review and meta-analysis. Ther Adv Chronic Dis 2022; 13:20406223211063059. [PMID: 35321402 PMCID: PMC8935404 DOI: 10.1177/20406223211063059] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 11/10/2021] [Indexed: 12/18/2022] Open
Abstract
Objective: To determine the effects of nonsurgical, minimally or noninvasive therapies on urge urinary incontinence (UUI) symptoms and quality of life (QoL) in individuals with neurogenic bladder (NGB). Data Sources: Cochrane library, EMBASE, MEDLINE, PEDro, Scopus, and Web of Science databases were searched from inception to September 2021. Review Methods: Randomized controlled trials that compared therapies such as intravaginal electrical stimulation (IVES), transcutaneous electrical nerve stimulation (TENS), neuromuscular electrical stimulation (NMES), transcutaneous tibial nerve stimulation (TTNS), pelvic floor muscle training (PFMT), and behavioural therapy (BT) to control were included. Study screening, data extraction, and study quality assessments were performed by two independent authors. Results: Fourteen trials with 804 participants were included in the study after screening of 4281 potentially relevant articles. Meta-analyses revealed a significant effect of electrical stimulation on UUI due to multiple sclerosis (standardized mean difference (SMD): −0.614; 95% confidence interval (CI): −1.023, −0.206; p = 0.003) and stroke (SMD: −2.639; 95% CI: −3.804, −1.474; p = 0.000). The pooled analyses of TTNS (weighted mean difference (WMD): −12.406; 95% CI: −16.015, −8.797; p = 0.000) and BT (WMD: −9.117; 95% CI: −14.746, −3.487; p = 0.002) revealed significant effects of these interventions on QoL in people with Parkinson’s disease. However, meta-analyses revealed nonsignificant effects for PFMT (WMD: −0.751; 95% CI: −2.426, 0.924; p = 0.380) and BT (WMD: −0.597; 95% CI: −1.278, 0.083; p = 0.085) on UUI due to Parkinson’s disease. Conclusions: Our meta-analyses found electrical stimulation to be beneficial for improving the symptoms of UUI among people with multiple sclerosis and those with stroke. Our review also revealed that TTNS and BT might improve QoL for people with NGB due to Parkinson’s disease, although the effects of PFMT and BT on UUI warrant further investigation.
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Affiliation(s)
- Mohammed Usman Ali
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong Department of Medical Rehabilitation (Physiotherapy), University of Maiduguri, Maiduguri, Nigeria
| | - Kenneth Nai-Kuen Fong
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong
| | - Priya Kannan
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong
| | - Umar Muhammad Bello
- Centre for Eye and Vision Research (CEVR) Limited, Hong Kong, China; Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong Department of Physiotherapy, Yobe State University Teaching Hospital, Damaturu, Nigeria
| | - Georg S. Kranz
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
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Transecting the hypogastric nerve to uncover the bladder-inhibitory pathways involved with saphenous nerve stimulation in anesthetized rats. Auton Neurosci 2020; 226:102672. [DOI: 10.1016/j.autneu.2020.102672] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 02/07/2020] [Accepted: 04/02/2020] [Indexed: 01/03/2023]
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Potts BA, Degoski DJ, Brooks JM, Peterson AC, Nelson DE, Brink TS, Fraser MO. Timing of sacral neurostimulation is important for increasing bladder capacity in the anesthetized rat. Am J Physiol Renal Physiol 2019; 317:F1183-F1188. [PMID: 31411072 DOI: 10.1152/ajprenal.00167.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We assessed the effects of limited application of sacral neurostimulation (SNS) during bladder filling on bladder capacity using our previously published SNS model in rats. Female Sprague-Dawley rats (n = 24) were urethane anesthetized (1.2 g/kg sc) and implanted with jugular venous and transvesical bladder catheters. L6/S1 nerve trunks were isolated bilaterally, and two electrodes were placed on each exposed nerve. True bladder capacity (TBC) was determined using stable single-fill cystometrograms. In the first series of experiments, SNS was applied at the onset of bladder filling for 25%, 50%, 75%, and 100% of the previous control filling cycle duration (n = 10). In the second series of experiments, SNS was applied during the first, second, third, and fourth 25% and the first and second 50% of the control fill. In the first series, a significant increase in TBC was observed only when SNS was applied for 75% or 100% of the control fill duration (30% and 35%, respectively, P < 0.05). In the second series, significant increases in TBC only occurred during the fourth 25% period and second 50% period (32% and 43%, respectively, P < 0.001). Results from the second series also revealed an increase in subsequent single-fill bladder capacities (TBC) only when SNS was applied during the second 50% of the prior fill cycle. These data indicate that the application of SNS during the final 50% of the bladder fill cycle is necessary and sufficient for increasing bladder capacity.
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Affiliation(s)
- Bradley A Potts
- Division of Urology, Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | | | | | - Andrew C Peterson
- Division of Urology, Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Dwight E Nelson
- Research and Core Technology, Restorative Therapies Group, Medtronic Incorporated, Minneapolis, Minnesota
| | - Thaddeus S Brink
- Research and Core Technology, Restorative Therapies Group, Medtronic Incorporated, Minneapolis, Minnesota
| | - Matthew O Fraser
- Division of Urology, Department of Surgery, Duke University Medical Center, Durham, North Carolina.,Institute for Medical Research, Durham, North Carolina.,Research and Development Department, Durham Veterans Affairs Medical Center, Durham, North Carolina
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Bourbeau DJ, Gustafson KJ, Brose SW. At-home genital nerve stimulation for individuals with SCI and neurogenic detrusor overactivity: A pilot feasibility study. J Spinal Cord Med 2019; 42:360-370. [PMID: 29334338 PMCID: PMC6522983 DOI: 10.1080/10790268.2017.1422881] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
OBJECTIVE Neurogenic bladder dysfunction, including neurogenic detrusor overactivity (NDO) is one of the most clinically significant problems for persons with spinal cord injury (SCI), affecting health and quality of life. Genital nerve stimulation (GNS) can acutely inhibit NDO-related reflex bladder contractions and increase bladder capacity. However, it is unknown if GNS can improve urinary continence or help meet individuals' bladder management goals during sustained use, which is required for GNS to be clinically effective. DESIGN Subjects maintained voiding diaries during a one-month control period without stimulation, one month with at-home GNS, and one month after GNS. Urodynamics and quality of life assessments were conducted after each treatment period, and a satisfaction survey was taken at study completion. SETTING Subject screening and clinical procedures were conducted at the Louis Stokes Cleveland VA Medical Center. Stimulation use and voiding diary entries were conducted in subjects' homes. PARTICIPANTS Subjects included five men with SCI and NDO. INTERVENTIONS This study tested one month of at-home portable non-invasive GNS. OUTCOME MEASURES The primary outcome measure was leakage events per day. Secondary outcome measures included self-reported subject satisfaction, bladder capacity, and stimulator use frequency. RESULTS GNS reduced the number of leakage events from 1.0 ± 0.5 to 0.1 ± 0.4 leaks per day in the four subjects who reported incontinence data. All study participants were satisfied that GNS met their bladder goals; wanted to continue using GNS; and would recommend it to others. CONCLUSIONS Short term at-home GNS reduced urinary incontinence and helped subjects meet their bladder management goals. These data inform the design of a long-term clinical trial testing of GNS as an approach to reduce NDO.
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Affiliation(s)
- Dennis J. Bourbeau
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center, ClevelandOhio,Department of Physical Medicine and Rehabilitation, MetroHealth Medical Center, Cleveland, Ohio,Cleveland VA Functional Electrical Stimulation Center, Cleveland, Ohio,Correspondence to: Dennis J. Bourbeau, PhD. Research Service 151(W), 10701 East Blvd, Cleveland, OH44106, USA.
| | - Kenneth J. Gustafson
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center, ClevelandOhio,Cleveland VA Functional Electrical Stimulation Center, Cleveland, Ohio,Departments of Biomedical Engineering and Urology, Case Western Reserve University, Cleveland, Ohio
| | - Steven W. Brose
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center, ClevelandOhio,Cleveland VA Functional Electrical Stimulation Center, Cleveland, Ohio,Department of Physical Medicine & Rehabilitation, Case Western Reserve University, Cleveland, Ohio,Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
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Choudhary M, van Mastrigt R, van Asselt E. The frequency spectrum of bladder non-voiding activity as a trigger-event for conditional stimulation: Closed-loop inhibition of bladder contractions in rats. Neurourol Urodyn 2018; 37:1567-1573. [DOI: 10.1002/nau.23504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 12/27/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Mahipal Choudhary
- Department of Urology; Sector FURORE; Erasmus MC; Rotterdam The Netherlands
| | - Ron van Mastrigt
- Department of Urology; Sector FURORE; Erasmus MC; Rotterdam The Netherlands
| | - Els van Asselt
- Department of Urology; Sector FURORE; Erasmus MC; Rotterdam The Netherlands
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MacDiarmid SA, John MS, Yoo PB. A pilot feasibility study of treating overactive bladder patients with percutaneous saphenous nerve stimulation. Neurourol Urodyn 2018; 37:1815-1820. [PMID: 29464764 DOI: 10.1002/nau.23531] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 01/26/2018] [Indexed: 11/06/2022]
Abstract
AIMS Effective long-term treatment of overactive bladder (OAB) remains a significant clinical challenge. We present our initial experience with a new bladder neuromodulation method that electrically targets the saphenous nerve (SAFN). METHODS A total of 18 OAB patients (female, 55-84 years) were provided with percutaneous SAFN stimulation. The SAFN was targeted with a needle electrode inserted below the medial condyle of the tibia. Activation of the SAFN was confirmed by the patient's perception of paresthesia radiating down the leg. Electrical stimulation was applied for 30 min and subsequently repeated weekly for 3 months. The effects of stimulation were assessed by a 4-day bladder diary and quality-of-life questionaire (OAB-q). RESULTS Percutaneous SAFN stimulation was confirmed in all 16 patients who completed the study, and no adverse events were reported. Positive response to SAFN stimulation was achieved in 87.5% (14 of 16) of patients, as determined by either a minimum 50% reduction in bladder symptoms or a minimum 10 point increase in the HRQL total score. CONCLUSIONS Electrical activation of the SAFN was consistently achieved using anatomical landmarks and patient feedback. The procedure was well tolerated and, based on our small cohort of patients, appears efficacious, and safe. This pilot study provides early feasibility data that points to a promising new intervention for treating OAB.
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Affiliation(s)
| | - M Sasha John
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Paul B Yoo
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada.,Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
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Moazzam Z, Duke AR, Yoo PB. Posterior tibial nerve stimulation using a wirelessly powered system in anesthetized cats. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2016:4459-4462. [PMID: 28269268 DOI: 10.1109/embc.2016.7591717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Posterior Tibial Nerve Stimulation (PTNS) is an effective overactive bladder (OAB) therapy where electrical pulses are typically delivered once per week in a 12-week stimulation regime. While the mechanism of action remains unknown, effective long-term delivery of PTNS has recently become a subject of concern. To this end, a multi-contact electrode was surgically placed in the hind limb region of anesthetized cats to (1) investigate the feasibility of using a wirelessly powered system to stimulate PTN afferents and (2) characterize implant-driven effects of stimulation frequency on modulating bladder activity. Using an isovolumetric model, short-duration, supra-threshold stimulation trials were applied with frequencies ranging from 2-20 Hz. The results provide first pre-clinical evidence of frequency-dependent modulation of bladder function supporting the use of a novel therapeutic approach that can be clinically translated to potentially address multiple symptoms of lower urinary tract system.
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Moazzam Z, Duke AR, Yoo PB. Inhibition and Excitation of Bladder Function by Tibial Nerve Stimulation Using a Wirelessly Powered Implant: An Acute Study in Anesthetized Cats. J Urol 2016; 196:926-33. [PMID: 27154823 DOI: 10.1016/j.juro.2016.04.077] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/26/2016] [Indexed: 10/21/2022]
Abstract
PURPOSE Tibial nerve stimulation is a minimally invasive neuromodulation treatment of overactive bladder. However, in addition to our limited understanding of the underlying mechanisms, there are also questions regarding the long-term delivery of tibial nerve stimulation therapy in patients. We aimed to characterize the effects of stimulation frequency using a wirelessly powered implantable stimulation device. METHODS AND MATERIALS Six α-chloralose anesthetized adult male cats were used in this study. A multicontact lead was surgically implanted subcutaneously in the hind limb and used to stimulate the tibial nerve. Using an isovolumetric bladder a short duration of electrical pulses was applied at amplitudes 3 times the motor threshold and at frequencies from 2 to 20 Hz. RESULTS Implant driven stimulation of the tibial nerve resulted in frequency dependent activation of bladder reflexes. Low frequency tibial nerve stimulation (2 Hz) consistently evoked excitatory responses (mean ± SE 32.9% ± 3.8%). In contrast, higher frequency tibial nerve stimulation (6 to 20 Hz) inhibited bladder function (overall mean 14.9% ± 2.4%). Although low foot motor thresholds were achieved at initial implantation (mean 0.83 ± 0.05 mA), a notable elevation in threshold amplitude was observed 5 hours after implantation. CONCLUSIONS To our knowledge this study provides the first evidence of frequency dependent modulation of bladder function in anesthetized cats. The inhibitory influence of tibial nerve stimulation at frequencies above 6 Hz transitioned to an excitatory effect at 2 Hz. Taken together these preclinical data support the feasibility of using a wirelessly powered implantable device to potentially modulate bladder function in patients.
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Affiliation(s)
- Zainab Moazzam
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | | | - Paul B Yoo
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada.
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Tai C, Ogagan PD, Chen G, Larson JA, Shen B, Wang J, Roppolo JR, de Groat WC. Involvement of opioid receptors in inhibition of bladder overactivity induced by foot stimulation in cats. J Urol 2012; 188:1012-6. [PMID: 22819119 PMCID: PMC3690128 DOI: 10.1016/j.juro.2012.04.096] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Indexed: 01/23/2023]
Abstract
PURPOSE We examined the role of opioid receptors in the inhibition of bladder overactivity induced by electrical stimulation of the foot. MATERIALS AND METHODS Experiments were done in 6 cats under α-chloralose anesthesia when the bladder was infused with saline or 0.25% acetic acid. Naloxone (1 mg/kg intravenously) was administered to block opioid receptors. To modulate reflex bladder activity electrical stimulation (5 Hz, 0.2 millisecond pulse width) was applied to the foot via skin surface electrodes at intensities of multiple times the threshold needed to induce observable toe movement. RESULTS Acetic acid irritated the bladder, induced bladder overactivity and significantly decreased bladder capacity to a mean ± SE 25.3% ± 5.9% that of saline control capacity (p = 0.0001). Foot stimulation at 4T suppressed acetic acid induced bladder overactivity and significantly increased bladder capacity to 47.1% ± 5.9% of control (p = 0.0007). Naloxone did not significantly change bladder capacity during acetic acid irritation but it completely eliminated the inhibition of bladder overactivity induced by foot stimulation. CONCLUSIONS Results indicate that opioid receptors have an important role in foot afferent inhibition of bladder overactivity. This raises the possibility that opioid receptors might be used as a pharmacological target to enhance the efficacy of foot stimulation for inhibiting bladder overactivity.
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Affiliation(s)
- Changfeng Tai
- Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.
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Snellings AE, Grill WM. Effects of stimulation site and stimulation parameters on bladder inhibition by electrical nerve stimulation. BJU Int 2012; 110:136-43. [DOI: 10.1111/j.1464-410x.2011.10789.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Tai C, Shen B, Wang J, Liu H, Subbaroyan J, Roppolo JR, de Groat WC. Inhibition of bladder overactivity by stimulation of feline pudendal nerve using transdermal amplitude-modulated signal (TAMS). BJU Int 2011; 109:782-7. [PMID: 21851548 DOI: 10.1111/j.1464-410x.2011.10410.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE • To develop a non-invasive neuromodulation method targeting the pudendal nerve. MATERIALS AND METHODS • Bladder overactivity induced by acetic acid (AA) irritation was partially suppressed by electrical stimulation of the pudendal nerve in α-chloralose anaesthetized cats using a transdermal amplitude-modulated signal (TAMS). RESULTS • During cystometrography (CMG), intravesical infusion of 0.25% AA significantly decreased the mean (se) bladder capacity to 28.8 (5.9)% of the capacity measured during saline infusion. • The TAMS stimulation inhibited AA-induced bladder overactivity at 5, 7 and 10 Hz, and significantly increased the mean (se) bladder capacity to 61.8 (9.9)%, 51.3 (14.5)%, 53.6 (14.9)%, respectively, of the control capacity during saline infusion, whereas stimulation at 20-40 Hz had no effect. • Under isovolumetric conditions at a bladder volume ranging between 130 to 160% of the bladder capacity measured during AA infusion, TAMS stimulation at all frequencies (5-40 Hz) significantly suppressed the irritation-induced rhythmic bladder contractions, reduced the area under the bladder pressure curve, and decreased the frequency of bladder contractions. However, the amplitude of rhythmic bladder contractions was only significantly decreased at stimulation frequencies of 5-20 Hz. • At bladder volumes above the AA control capacity, TAMS stimulation with frequencies of 20-30 Hz had an excitatory effect, resulting in large amplitude (>25 cmH(2) O) bladder contractions. CONCLUSIONS • TAMS stimulation targeting the cat pudendal nerve can inhibit C-fibre afferent-mediated bladder overactivity. • Thus, clinical research seems warranted to explore the usefulness of this technology for patients with overactive bladder symptoms.
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Affiliation(s)
- Changfeng Tai
- Department of Urology, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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Shen B, Roppolo JR, Subbaroyan J, Diubaldi A, Wahlgren S, de Groat WC, Tai C. Neuromodulation of bladder activity by stimulation of feline pudendal nerve using a transdermal amplitude modulated signal (TAMS). Neurourol Urodyn 2011; 30:1686-94. [PMID: 21404324 DOI: 10.1002/nau.21084] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 02/03/2011] [Indexed: 11/12/2022]
Abstract
AIM To develop a non-invasive neuromodulation method to regulate bladder activity. METHODS Neuromodulation of bladder activity was investigated in felines with an intact spinal cord under α-chloralose anesthesia using a transcutaneous stimulation method with surface electrodes attached to the skin area between the base of the tail and the sciatic notch. RESULTS The bladder could be either inhibited or excited depending on stimulation frequency and bladder volume. With the bladder distended to induce large amplitude rhythmic isovolumetric bladder contractions, stimulation at a frequency between 5 and 7 Hz significantly suppressed the contractions. Stimulation applied during a cystometrogram (CMG) also increased bladder capacity by 44.3 ± 10.8%. At a frequency between 20 and 40 Hz the inhibitory effect on rhythmic bladder contractions was weak and did not increase bladder capacity during CMG. At low bladder volumes ranging between 60% and 100% of the bladder capacity 20 Hz stimulation-induced small amplitude (21.2 ± 14.6 cmH(2) O) bladder contractions. However, stimulation at 20 Hz induced large amplitude (111.7 ± 22.2 cmH(2) O) bladder contractions at a bladder volume about 100-110% of the bladder capacity after the rhythmic bladder contractions were completely inhibited by the inhibitory 5 Hz stimulation. CONCLUSIONS Both inhibitory and excitatory effects on bladder activity can be obtained in cats using the non-invasive neural stimulation approach. This pre-clinical study warrants a further clinical trial to investigate the possibility of using this non-invasive stimulation method to treat incontinence or urinary retention.
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Affiliation(s)
- Bing Shen
- Department of Urology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Elkelini MS, Abuzgaya A, Hassouna MM. Mechanisms of action of sacral neuromodulation. Int Urogynecol J 2011; 21 Suppl 2:S439-46. [PMID: 20972548 DOI: 10.1007/s00192-010-1273-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The lower urinary tract dysfunction encompasses voiding, postvoiding, and storage symptoms. Conventional treatment modalities include pharmacotherapy and behavioural therapy. Sacral neuromodulation (SNM) is a safe and minimally invasive treatment modality that has recently gained wide acceptance in the management of urinary urge incontinence, urge frequency, and nonobstructive urinary retention, in particular, among those patients with conditions refractory to conventional methods. We searched multiple electronic databases through June 30, 2009 for eligible studies. We examined published clinical and experimental studies concerning the mechanisms of action of SNM. In the first part of the manuscript, we describe the anatomy and functions of the lower urinary tract including the reflexes involved in its functions and then review the pathophysiology of major types of the lower urinary tract dysfunction. In the second part, we discuss different ways for SNM to control various types of voiding dysfunction. The lower urinary tract dysfunctions affect millions of people worldwide and have a severe impact on their quality of life. SNM offers a safe and minimally invasive modality in the treatment of voiding dysfunctions, especially in patients with conditions refractory to conventional therapies.
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Affiliation(s)
- Mohamed S Elkelini
- Division of Urology, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
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Tai C, Shen B, Chen M, Wang J, Liu H, Roppolo JR, de Groat WC. Suppression of bladder overactivity by activation of somatic afferent nerves in the foot. BJU Int 2011; 107:303-9. [PMID: 20394612 DOI: 10.1111/j.1464-410x.2010.09358.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To investigate the possibility of suppressing bladder overactivity by electrical activation of somatic afferent nerves in the foot. MATERIALS AND METHODS Cats with an intact spinal cord were studied under α-chloralose anaesthesia. Bladder pressure was recorded via a urethral catheter. Foot stimulation was applied via surface pad electrodes attached to the skin of the front or hind foot. RESULTS Reflex micturition was inhibited by electrical stimulation of the hind foot at either low (5 Hz) or high (20 Hz) frequencies, but stimulation of the front foot was ineffective. The mean (sem) bladder capacity during a saline infusion cystometrogram (CMG) was significantly (P < 0.05) increased to 153.2 (18.2)% and 136.9 (14.3)% of the control bladder capacity by stimulation at frequencies of 5 Hz and 20 Hz, respectively. Intravesical infusion of 0.25% acetic acid (AA) induced bladder overactivity and reduced bladder capacity to 20.3 (8.9)% of the control capacity measured during saline infusion. Foot stimulation inhibited the AA-induced bladder overactivity recorded under isovolumetric conditions, and significantly (P < 0.05) increased bladder capacity during AA infusion. However, it only restored the small bladder capacity caused by AA irritation to 40-50% of the control bladder capacity measured during saline infusion. The effect of foot stimulation did not persist after termination of stimulation during repeated CMG tests. CONCLUSIONS This study shows the potential of noninvasive transcutaneous electrical stimulation of somatic nerves in the foot to inhibit reflex bladder activity and treat overactive bladder symptoms.
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Affiliation(s)
- Changfeng Tai
- Department of Urology, University of Pittsburgh, Pittsburgh, PA, USA.
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Tai C, Chen M, Shen B, Wang J, Liu H, Roppolo JR, de Groat WC. Plasticity of urinary bladder reflexes evoked by stimulation of pudendal afferent nerves after chronic spinal cord injury in cats. Exp Neurol 2010; 228:109-17. [PMID: 21192927 DOI: 10.1016/j.expneurol.2010.12.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 12/13/2010] [Accepted: 12/15/2010] [Indexed: 01/23/2023]
Abstract
Bladder reflexes evoked by stimulation of pudendal afferent nerves (PudA-to-Bladder reflex) were studied in normal and chronic spinal cord injured (SCI) adult cats to examine the reflex plasticity. Physiological activation of pudendal afferent nerves by tactile stimulation of the perigenital skin elicits an inhibitory PudA-to-Bladder reflex in normal cats, but activates an excitatory reflex in chronic SCI cats. However, in both normal and chronic SCI cats electrical stimulation applied to the perigenital skin or directly to the pudendal nerve induces either inhibitory or excitatory PudA-to-Bladder reflexes depending on stimulation frequency. An inhibitory response occurs at 3-10 Hz stimulation, but becomes excitatory at 20-30 Hz. The inhibitory reflex activated by electrical stimulation significantly (P<0.05) increases the bladder capacity to about 180% of control capacity in normal and chronic SCI cats. The excitatory reflex significantly (P<0.05) reduces bladder capacity to about 40% of control capacity in chronic SCI cats, but does not change bladder capacity in normal cats. Electrical stimulation of pudendal afferent nerves during slow bladder filling elicits a large amplitude bladder contraction comparable to the contraction induced by distension alone. A bladder volume about 60% of bladder capacity was required to elicit this excitatory reflex in normal cats; however, in chronic SCI cats a volume less than 20% of bladder capacity was sufficient to unmask an excitatory response. This study revealed the co-existence of both inhibitory and excitatory PudA-to-Bladder reflex pathways in cats before and after chronic SCI. However our data combined with published electrophysiological data strongly indicates that the spinal circuitry for both the excitatory and inhibitory PudA-to-Bladder reflexes undergoes a marked reorganization after SCI.
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Affiliation(s)
- Changfeng Tai
- Department of Urology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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Influence of naloxone on inhibitory pudendal-to-bladder reflex in cats. Exp Neurol 2010; 224:282-91. [PMID: 20382144 DOI: 10.1016/j.expneurol.2010.04.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 03/31/2010] [Accepted: 04/01/2010] [Indexed: 01/23/2023]
Abstract
To determine the involvement of opioid receptors in the inhibitory pudendal-to-bladder reflex, the effect of naloxone (0.01-1 mg/kg, i.v.), an opioid receptor antagonist, on the inhibition of bladder activity evoked by pudendal nerve stimulation was investigated in alpha-chloralose anesthetized cats. The inhibition of reflex isovolumetric bladder contractions induced by pudendal nerve stimulation (5-10 Hz) at intensity threshold (T) for producing complete inhibition was significantly suppressed by naloxone at a high dose (0.3 mg/kg). However, the inhibition elicited at higher intensities (1.5-3 T) was not changed. Naloxone (1 mg/kg) did not alter the frequency dependence of the inhibitory effect of pudendal stimulation. During cystometrograms (CMGs) pudendal nerve stimulation significantly increased bladder capacity to 155.1+/-24.5% and 163.4+/-10% of the control at stimulation intensities of 1 T and 1.5-3 T, respectively. After administration of naloxone (1 mg/kg), the bladder capacity during pudendal nerve stimulation at inhibition threshold (1 T) was not significantly different from control, but it was significantly increased at higher intensities (1.5-3 T). Naloxone alone markedly reduced bladder capacity to 43+/-11.1% of the control, and pudendal stimulation completely reversed this facilitatory effect. This study revealed that activation of opioid receptors contributes to or facilitates the inhibitory pudendal-to-bladder reflex. The reduction in bladder capacity after naloxone treatment also indicates that endogenous opioid peptides mediate a tonic inhibition of micturition. Understanding the neurotransmitter mechanisms involved in the inhibitory pudendal-to-bladder reflex could promote the development of new treatments for bladder overactivity and incontinence.
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Yoo PB, Horvath EE, Amundsen CL, Webster GD, Grill WM. Intraurethral activation of excitatory bladder reflexes in persons with spinal cord injury. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2010; 2009:6781-4. [PMID: 19964708 DOI: 10.1109/iembs.2009.5333982] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Electrical activation of an excitatory reflex between sensory fibers in the pudendal nerve and the bladder has been demonstrated in cats and is a potential means of restoring micturition function in persons with spinal cord injury. We investigated the clinical feasibility of activating this reflex to restore bladder function in persons with spinal cord injury by using intraurethral electrical stimulation to activate pudendal sensory fibers innervating the urethra. Excitatory bladder responses (contractions) were evoked by trains of electrical pulses applied to either the proximal (29.7 +/- 11.6 cmH2O) or distal (30.2 +/- 11.6 cmH2O) segment of the urethra. The results indicate that an excitatory reflex between pudendal nerve afferents and the bladder exists in humans with spinal injury and may provide a substrate for restoring micturition function.
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Affiliation(s)
- Paul B Yoo
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA
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Wang J, Liu H, Shen B, Roppolo JR, de Groat WC, Tai C. Bladder inhibition or excitation by electrical perianal stimulation in a cat model of chronic spinal cord injury. BJU Int 2008; 103:530-6. [PMID: 19007383 DOI: 10.1111/j.1464-410x.2008.08029.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To test the hypothesis that perianal electrical stimulation (PES) in chronic spinal cord-injured (SCI) cats could induce frequency-dependent inhibitory or excitatory reflex bladder responses. MATERIALS AND METHODS The experiments were conducted > or =4-5 weeks after spinal cord transection at the T9-T10 level. PES was applied via a pair of hook electrodes to the perianal skin area in three awake female cats with chronic SCI. A double-lumen balloon catheter was inserted through the urethra into the bladder to monitor bladder pressure and infuse saline (2-4 mL/min). RESULTS Under isovolumetric conditions PES at 3-10 Hz significantly inhibited large-amplitude reflex bladder activity induced by bladder distension above the micturition volume threshold. However, PES at 20-50 Hz induced large-amplitude bladder contractions when the bladder volume was below the micturition volume threshold. Inhibitory PES (7 Hz) significantly increased the mean (sem) bladder capacity by 40 (10)% when it was applied continuously during cystometrography. The optimum excitatory PES (30 Hz) induced large-amplitude (>25 cmH(2)O), long-duration (>20 s) bladder contractions at a wide range of bladder volumes (10-90% of bladder capacity). CONCLUSIONS This study showed that activation of pudendal afferent fibres by PES could induce frequency-dependent reflex bladder responses in awake cats with chronic SCI, indicating that a possible noninvasive treatment based on PES could be developed to restore both continence and micturition function for patients with SCI.
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Affiliation(s)
- Jicheng Wang
- Department of Urology, University of Pittsburgh, Pittsburgh, PA 15261, USA
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Jarvis JC, Rijkhoff NJM. Functional Electrical Stimulation for Control of Internal Organ Function. Neuromodulation 2008; 4:155-64. [DOI: 10.1046/j.1525-1403.2001.00155.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Yoo PB, Woock JP, Grill WM. Bladder activation by selective stimulation of pudendal nerve afferents in the cat. Exp Neurol 2008; 212:218-25. [PMID: 18502417 DOI: 10.1016/j.expneurol.2008.04.010] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 04/08/2008] [Accepted: 04/09/2008] [Indexed: 01/19/2023]
Abstract
Bladder contractions evoked by pudendal nerve stimulation in both spinal intact and spinal transected cats support the possibility of restoring urinary function in persons with chronic spinal cord injury (SCI). However, electrically evoked bladder responses in persons with SCI were limited to transient contractions at relatively low pressures. This prompted the present study, which presents a detailed quantification of the responses evoked by selective stimulation of individual branches of the pudendal nerve at different stimulation frequencies. In spinal intact cats anesthetized with alpha-chloralose, selective frequency-dependent electrical activation of the sensory (2 Hz<or=f<or=50 Hz), cranial sensory (f<or=5 Hz), dorsal genital (f>or=20 Hz) and rectal perineal (f<or=10 Hz) branches of the pudendal nerve evoked sustained bladder contractions dependent on the stimulation frequency. Contractions evoked by selective electrical stimulation resulted in significant increases in voiding efficiency compared to bladder emptying by distension-evoked contractions (p(ANOVA)<0.05). Acute spinal transection abolished reflex bladder contractions evoked by low frequency stimulation of the cranial sensory or rectal perineal branches, whereas contractions evoked by high frequency stimulation of the dorsal genital branch remained intact. This study presents evidence for two distinct micturition pathways (spino-bulbo-spinal vs. spinal reflexes) activated by selective afferent pudendal nerve stimulation, the latter of which may be applied to restore bladder function in persons with SCI.
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Affiliation(s)
- Paul B Yoo
- Department of Biomedical Engineering, Duke University, Hudson Hall, Room 136, Box 90281, Durham, NC 27708-0281, USA.
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Tai C, Shen B, Wang J, Chancellor MB, Roppolo JR, de Groat WC. Inhibitory and excitatory perigenital-to-bladder spinal reflexes in the cat. Am J Physiol Renal Physiol 2008; 294:F591-602. [PMID: 18160624 PMCID: PMC3405732 DOI: 10.1152/ajprenal.00443.2007] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study revealed that in awake chronic spinal cord-injured (SCI) cats reflexes from perigenital skin area to the bladder can be either inhibitory or excitatory. Electrical perigenital stimulation at frequencies between 5 and 7 Hz significantly inhibited large-amplitude rhythmic reflex bladder activity, whereas frequencies between 20 and 40 Hz induced large-amplitude bladder contractions even at low bladder volumes when reflex bladder activity was absent. Both inhibitory and excitatory effects were enhanced as the stimulation intensity increased (5-30 V, 0.2-ms pulse width). During cystometrograms, the inhibitory stimulation (7 Hz) significantly increased the micturition volume threshold 35 +/- 13% above the control volume, while the excitatory stimulation (30 Hz) significantly reduced the threshold 21 +/- 3%. Mechanical perigenital stimulation applied by repeated light stroking of the perigenital skin with a cotton swab only induced an excitatory effect on the bladder. Both electrical and mechanical perigenital stimuli induced large-amplitude (>30 cm H(2)O) bladder contractions that were relatively consistent over a range of bladder volumes (10-90% of the capacity). However, the excitatory electrical stimulation only induced bladder contractions lasting on average 42.2 +/- 3.9 s, but the mechanical stimulation induced bladder contractions that lasted as long as the stimulation continued (2-3 min). Excitatory electrical or mechanical perigenital stimulation also induced poststimulus voiding. The ability to either inhibit or excite the bladder by noninvasive methods could significantly transform the current clinical management of bladder function after SCI.
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Affiliation(s)
- Changfeng Tai
- Department of Urology, University, of Pittsburgh, Pittsburgh, PA 15261, USA.
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Tai C, Wang J, Wang X, Roppolo JR, de Groat WC. Voiding reflex in chronic spinal cord injured cats induced by stimulating and blocking pudendal nerves. Neurourol Urodyn 2008; 26:879-86. [PMID: 17563108 PMCID: PMC2821079 DOI: 10.1002/nau.20430] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AIMS To induce efficient voiding in chronic spinal cord injured (SCI) cats. METHODS Voiding reflexes induced by bladder distension or by electrical stimulation and block of pudendal nerves were investigated in chronic SCI cats under alpha-chloralose anesthesia. RESULTS The voiding efficiency in chronic SCI cats induced by bladder distension was very poor compared to that in spinal intact cats (7.3 +/- 0.9% vs. 93.6 +/- 2.0%, P < 0.05). In chronic SCI cats continuous stimulation of the pudendal nerve on one side at 20 Hz induced large amplitude bladder contractions, but failed to induce voiding. However, continuous pudendal nerve stimulation (20 Hz) combined with high-frequency (10 kHz) distal blockade of the ipsilateral pudendal nerve elicited efficient (73.2 +/- 10.7%) voiding. Blocking the pudendal nerves bilaterally produced voiding efficiency (82.5 +/- 4.8%) comparable to the efficiency during voidings induced by bladder distension in spinal intact cats, indicating that the external urethral sphincter (EUS) contraction was caused not only by direct activation of the pudendal efferent fibers, but also by spinal reflex activation of the EUS through the contralateral pudendal nerve. The maximal bladder pressure and average flow rate induced by stimulation and bilateral pudendal nerve block in chronic SCI cats were also comparable to those in spinal intact cats. CONCLUSIONS This study shows that after the spinal cord is chronically isolated from the pontine micturition center, bladder distension evokes a transient, inefficient voiding reflex, whereas stimulation of somatic afferent fibers evokes a strong, long duration, spinal bladder reflex that elicits efficient voiding when combined with blockade of somatic efferent fibers in the pudendal nerves.
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Affiliation(s)
- Changfeng Tai
- Department of Pharmacology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.
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Tai C, Wang J, Wang X, de Groat WC, Roppolo JR. Bladder inhibition or voiding induced by pudendal nerve stimulation in chronic spinal cord injured cats. Neurourol Urodyn 2007; 26:570-577. [PMID: 17304521 DOI: 10.1002/nau.20374] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AIMS To investigate pudendal-to-bladder spinal reflexes in chronic spinal cord injured (SCI) cats induced by electrical stimulation of the pudendal nerve. METHODS Bladder inhibition or voiding induced by pudendal nerve stimulation at different frequencies (3 or 20 Hz) was studied in three female, chronic SCI cats under alpha-chloralose anesthesia. RESULTS Voiding induced by a slow infusion (2-4 ml/min) of saline into the bladder was very inefficient (voiding efficiency=7.3%+/-0.9%). Pudendal nerve stimulation at 3 Hz applied during the slow infusion inhibited reflex bladder activity, and significantly increased bladder capacity to 147.2+/-6.1% of its control capacity. When the 3-Hz stimulation was terminated, voiding rapidly occurred and the voiding efficiency was increased to 25.4+/-6.1%, but residual bladder volume was not reduced. Pudendal nerve stimulation at 20 Hz induced large bladder contractions, but failed to induce voiding during the stimulation due to the direct activation of the motor pathway to the external urethral sphincter. However, intermittent pudendal nerve stimulation at 20 Hz induced post-stimulus voiding with 78.3+/-12.1% voiding efficiency. The voiding pressures (39.3+/-6.2 cmH2O) induced by the intermittent pudendal nerve stimulation were higher than the voiding pressures (23.1+/-1.7 cmH2O) induced by bladder distension. The flow rate during post-stimulus voiding induced by the intermittent pudendal nerve stimulation was significantly higher (0.93+/-0.04 ml/sec) than during voiding induced by bladder distension (0.23+/-0.07 ml/sec). CONCLUSIONS This study indicates that a neural prosthetic device based on pudendal nerve stimulation might be developed to restore micturition function for people with SCI.
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Affiliation(s)
- Changfeng Tai
- Department of Pharmacology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Jicheng Wang
- Department of Pharmacology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Xianchun Wang
- Department of Pharmacology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - William C de Groat
- Department of Pharmacology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - James R Roppolo
- Department of Pharmacology, University of Pittsburgh, Pittsburgh, Pennsylvania
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Abstract
Pharmacotherapy is the first-line treatment for overactive bladder, but many patients discontinue drug therapy because of intolerable side effects, expense, or lack of longterm adherence. Alternative treatments are needed for patients who are unable to tolerate pharmacotherapy or who do not derive the desired benefits. Sacral nerve stimulation therapy has evolved into one of the most widely accepted treatment modalities in the arena of neurourology. Sacral nerve stimulation activates or "resets" the somatic afferent inputs that play a pivotal role in the modulation of sensory processing for micturition reflex pathways in the spinal cord. This minimally invasive technology offers a safe, reliable, and durable treatment for lower urinary tract dysfunction.
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Affiliation(s)
- Wendy W Leng
- Department of Urology, University of Pittsburgh School of Medicine, 3471 Fifth Avenue, Suite 700, Pittsburgh, PA 15213, USA.
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Boggs JW, Wenzel BJ, Gustafson KJ, Grill WM. Frequency-dependent selection of reflexes by pudendal afferents in the cat. J Physiol 2006; 577:115-26. [PMID: 16945977 PMCID: PMC2000666 DOI: 10.1113/jphysiol.2006.111815] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Activation of urethral or genital afferents of the pudendal nerve can elicit or inhibit micturition, and low frequency stimulation of the compound pudendal nerve (PN) is known to produce a continence response. The present study demonstrates that PN stimulation also can elicit a micturition-like response and that the response to PN stimulation is dependent on stimulation frequency. We measured the changes in bladder pressure and external urethral sphincter (EUS) electroneurogram (ENG) evoked by PN stimulation before and up to 16 h after spinal cord transection (SCT) in cats anaesthetized with alpha-chloralose. Low frequency (10 Hz) stimulation elicited a continence-like response, including inhibition of the bladder and activation of the EUS, but mid-frequency (33 Hz) stimulation produced a micturition-like response, including excitation of the bladder without activation of the EUS. The dependence of the response on stimulus frequency was linked to interpulse interval as the same number of pulses at 10, 33 and 100 Hz produced different responses. Stimulation of the PN at 33 Hz produced bladder contractions before and 8 h after SCT provided the bladder contained a minimum volume of fluid. Only mid-range frequency stimulation with sufficient stimulus train duration produced a reduction in EUS ENG activity before and after SCT. In addition to a continence-like response, PN stimulation can also elicit a micturition-like response, and this response is dependent on stimulation frequency, stimulus train duration, and bladder volume. The ability to control the two principal functions of the bladder by pudendal nerve stimulation is an exciting prospect for neurorehabilitation.
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Affiliation(s)
- Joseph W Boggs
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
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Acute urodynamic effects of posterior tibial nerve stimulation on neurogenic detrusor overactivity in patients with MS. Eur Urol 2006; 51:464-70; discussion 471-2. [PMID: 16956713 DOI: 10.1016/j.eururo.2006.07.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2006] [Accepted: 07/20/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVES The aim of this study was to investigate whether acute electrical stimulation of the posterior tibial nerve could suppress detrusor contractions in multiple sclerosis (MS) patients with neurogenic detrusor overactivity. METHODS Two successive slow-fill cystometries (16 ml/min) were carried out in eight MS patients with neurogenic detrusor overactivity. The first filling served as control without stimulation. In the second filling, electrical stimulation using needle electrodes was applied automatically to the posterior tibial nerve when the detrusor pressure exceeded 10 cm H(2)O. An additional filling in which the needle electrodes were replaced by surface electrodes was carried out in three patients. RESULTS The control filling showed detrusor overactivity in eight patients, but electrical stimulation of the posterior tibial nerve failed to suppress detrusor contractions in all tested patients. CONCLUSIONS Although neuromodulative effects may be obtained with therapeutic electrical stimulation of the posterior tibial nerve, no acute effects were demonstrated. For this reason, electrical stimulation of pudendal afferents remains the only option if acute suppression of a detrusor contraction is required.
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Wenzel BJ, Boggs JW, Gustafson KJ, Grill WM. Closed loop electrical control of urinary continence. J Urol 2006; 175:1559-63. [PMID: 16516045 DOI: 10.1016/s0022-5347(05)00657-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2005] [Indexed: 11/29/2022]
Abstract
PURPOSE Individuals with spinal cord injury or neurological disorders may have neurogenic detrusor contractions at low volumes (bladder hyperreflexia), which cause incontinence and can lead to significant health problems. Bladder contractions can be suppressed by electrical stimulation of inhibitory pathways but continuous activation may lead to habituation of the inhibitory reflex and loss of continence. We determined whether conditional stimulation with electrical stimulation of inhibitory pathways applied only at the onset of nascent bladder contractions allows the bladder to fill to a greater volume before continence is lost compared with continuous stimulation. MATERIALS AND METHODS In 6 alpha-chloralose anesthetized cats cystometry was performed to compare the volume at which continence was lost under the conditions of no stimulation, continuous stimulation and conditional electrical stimulation of inhibitory pathways. PNT ENG was used to detect the onset of bladder contractions and it served as the input to an event triggered control system that regulated conditional stimulation to maintain continence. RESULTS Conditional stimulation controlled by PNT ENG increased bladder capacity by 36% over no stimulation and by 15% over continuous stimulation (p <0.001 and 0.027, respectively). The event triggered control system decreased stimulation time by 67% compared to continuous stimulation. CONCLUSIONS Conditional electrical stimulation of inhibitory pathways is more effective than continuous stimulation. A control system triggered by PNT ENG can maintain urinary continence.
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Affiliation(s)
- Brian J Wenzel
- Departments of Biomedical Engineering, Duke University, Durham, North Carolina, USA
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Tai C, Smerin SE, de Groat WC, Roppolo JR. Pudendal-to-bladder reflex in chronic spinal-cord-injured cats. Exp Neurol 2005; 197:225-34. [PMID: 16271266 DOI: 10.1016/j.expneurol.2005.09.013] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2005] [Revised: 09/12/2005] [Accepted: 09/20/2005] [Indexed: 11/23/2022]
Abstract
The effects of pudendal nerve stimulation on reflex bladder activity were investigated in cats with chronic spinal cord injury (6-12 months) under alpha-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.
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Affiliation(s)
- Changfeng Tai
- Department of Pharmacology, University of Pittsburgh, W1354 Biomedical Science Tower, Pittsburgh, PA 15261, USA.
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Abstract
The authors believe that the principles underlying the multiple possible SNS mechanisms of action can be summarized as somatic afferent inhibition of sensory processing in the spinal cord. Regardless of whether the lower urinary tract dysfunction involves storage versus emptying abnormalities, the pudendal afferent signaling serves as a common crossroads in the neurologic wiring of the system. Not only can pudendal afferent input turn on voiding reflexes by sup-pressing the guarding reflex pathways, pudendal afferent input to the sacral spinal cord also can turn off supraspinally mediated hyperactive voiding by blocking ascending sensory pathway inputs. For these reasons, SNS can take advantage of the complex neurologic pathways described and offer successful treatment for a seemingly disparate group of lower urinary tract pathologies. SNS is a urologic technique that has proved safe and minimally invasive, and it holds great promise for many patients who have lower urinary tract dysfunction.
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Affiliation(s)
- Wendy W Leng
- Department of Urology, University of Pittsburgh School of Medicine, 3471 Fifth Avenue, Suite #700, Pittsburgh, PA 15213, USA.
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Chancellor MB, Chartier-Kastler EJ. Principles of Sacral Nerve Stimulation (SNS) for the Treatment of Bladder and Urethral Sphincter Dysfunctions. Neuromodulation 2001; 3:16-26. [DOI: 10.1046/j.1525-1403.2000.00015.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Grill WM. Electrical Activation of Spinal Neural Circuits: Application to Motor-System Neural Prostheses. Neuromodulation 2001; 3:97-106. [DOI: 10.1046/j.1525-1403.2000.00097.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Boyer S, Sawan M, Abdel-Gawad M, Robin S, Elhilali MM. Implantable selective stimulator to improve bladder voiding: design and chronic experiments in dogs. IEEE TRANSACTIONS ON REHABILITATION ENGINEERING : A PUBLICATION OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY 2000; 8:464-70. [PMID: 11204037 DOI: 10.1109/86.895949] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Among the treatments to enhance the bladder voiding, the sacral roots neurostimulation is one of the most promising techniques. The electrostimulation of sacral nerves provokes a simultaneous contraction of the detrusor muscle as well as the external urethral sphincter (EUS). A new simplified-architecture implantable stimulator with its wireless controller have been designed to investigate high-frequency inhibition stimulation strategies. This innovative technique based on high-frequency inhibition reduces sphincter activity during stimulation. Low-frequency current pulses also applied to the sacral roots induces contraction of the detrusor muscle resulting in low pressure voiding. Chronic experiments were carried out on ten male mongrel paraplegic dogs. One cuff electrode was implanted along with each stimulator for eight months. The animals were stimulated twice a day using the prototypes of our implantable selective stimulator while voided and residual urine volume were measured during the procedure. These experiments revealed that the proposed stimulation strategy enhances bladder voiding by more than 50% in comparison with low-frequency only stimulation. The residual urine volume was reduced to an average of 9% and low pressure micturition was achieved as shown by weekly cystourethrogram.
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Affiliation(s)
- S Boyer
- Department of Electrical and Computer Engineering, Ecole Polytechnique de Montréal, QC, Canada
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Walter JS, Wheeler JS, Cai W, King WW, Wurster RD. Evaluation of a suture electrode for direct bladder stimulation in a lower motor neuron lesioned animal model. IEEE TRANSACTIONS ON REHABILITATION ENGINEERING : A PUBLICATION OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY 1999; 7:159-66. [PMID: 10391586 DOI: 10.1109/86.769406] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The purpose of this study was to evaluate a "suture" type electrode for direct bladder stimulation in an animal model of a lower motor neuron lesion. During an initial surgery, five male cats were instrumented under anesthesia using multistranded, 316 LVM, stainless-steel, wire electrodes implanted on the bladder wall serosa above the trigone area. Electrodes were constructed with a needle attached to the end that was removed after suturing the electrode in place. Additional instrumentation included urinary bladder catheters (tubes) for pressure recording and filling, and hook type electrodes for leg and pelvic floor electromyography recording. Chronic bladder filling and stimulation studies were conducted in tethered animals three to four weeks following surgery. To test these electrodes in a spinal cord injury model, a lower motor neuron lesion was performed including the sacral cord and complete nerve roots at L6 and below. These animals were evaluated during weeks 3 and 10 after injury. Direct bladder stimulation induced active contractions and voiding both before and after spinal cord injury. Effective stimulation parameters consisted of 40 pulses per s, 300 micros to 1 ms pulse duration, a stimulation period from 3 to 4 s, and a stimulation current from 10 to 40 mA. Fluoroscopy revealed an open membranous urethra during stimulation and following stimulation. A small diameter penile urethra was observed to limit flow. Postmortem evaluation of the suture electrode revealed no abnormalities such as corrosion, migration into the bladder lumen or displacement. These findings indicate that suture electrodes are suitable and effective for short-term implantation in the lower motor neuron animal model.
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Affiliation(s)
- J S Walter
- Rehabilitation R&D Center, VA Hines Hospital, Research Service (151), IL 60141, USA
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Arabi K, Sawan MA. Electronic design of a multichannel programmable implant for neuromuscular electrical stimulation. IEEE TRANSACTIONS ON REHABILITATION ENGINEERING : A PUBLICATION OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY 1999; 7:204-14. [PMID: 10391591 DOI: 10.1109/86.769411] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
An advanced stimulator for neuromuscular stimulation of spinal cord injured patients has been developed. The stimulator is externally controlled and powered by a single encoded radio frequency carrier and has four independently controlled bipolar stimulation channels. It offers a wide range of reprogrammability and flexibility, and can be used in many neuromuscular electrical stimulation applications. The implant system is adaptable to patient's needs and to future developments in stimulation algorithms by reprogramming the stimulator. The stimulator is capable of generating a wide range of stimulation waveforms and stimulation patterns and therefore is very suitable for selective nerve stimulation techniques. The reliability of the implant has been increased by using a forward error detection and correction communication protocol and by designing the chip for structural testability based on scan test approach. Implemented testability scheme makes it possible to verify the complete functionality of the implant before and after implantation. The stimulators architecture is designed to be modular and therefore its different blocks can be reused as standard building blocks in the design and implementation of other neuromuscular prostheses. Design for low-power techniques have also been employed to reduce power consumption of the electronic circuitry.
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Affiliation(s)
- K Arabi
- Department of Electrical Engineering, Ecole de Technologie Supérieure, Montreal, P.Q., Canada
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Sawan M, Hassouna MM, Li JS, Duval F, Elhilali MM. Stimulator design and subsequent stimulation parameter optimization for controlling micturition and reducing urethral resistance. IEEE TRANSACTIONS ON REHABILITATION ENGINEERING : A PUBLICATION OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY 1996; 4:39-46. [PMID: 8798071 DOI: 10.1109/86.486056] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
An implantable computerized electrical stimulation system designed to induce bladder evacuation in animal models (dogs) after spinal cord transection has been realized and evaluated. This fully programmable system is based on a handheld device and generates a wide range of stimuli through multichannel implantable miniaturized stimulator. Using the new bladder stimulator and inducing reversible fatigue to the external sphincter via the pudendal nerve enables us to reduce the bladder outlet resistance, resulting in the proper emptying of the bladder during stimulation without the need for sacral nerve rhizotomies and the pudendal nerve neurectomies. Four chronically affected dogs were studied to determine the optimal stimulation parameters for inducing a sphincter fatigue that would reliably empty the bladder for the duration of the experiment. These parameters were: maximum amplitude of 1.5 mA +/- 0.5 SD, stimuli composed of a high frequency signal of 200 Hz +/- 50 SD modulated by a low frequency signal of 10 Hz +/- 5 SD, pulse width controlled by a duty-cycle of 20% +/- 10 SD, sacral nerve stimulation of 50 s +/- 25 SD and fatiguing duration of 20 s +/- 5 SD.
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Affiliation(s)
- M Sawan
- Department of Electrical and Computer Engineering, Ecole Polytechnique de Montréal, P.Q., Canada
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Arabi K, Sawan M. Implantable multiprogrammable microstimulator dedicated to bladder control. Med Biol Eng Comput 1996; 34:9-12. [PMID: 8857306 DOI: 10.1007/bf02637016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
An implantable multiprogrammable microstimulator that is intended to restore normal bladder functions (retention and incontinence) to spinal cord injured patients is presented. The implantable microstimulator circuitry is externally controlled and is powered by a single encoded radio frequency carrier and has four bipolar (eight monopolar) independently controlled channels. It offers a higher degree of reprogrammability and flexibility and can be used in any neuromuscular applications. The implant system is adaptable to the patient's needs and to future developments in stimulation algorithms, without changing the implant. Features of the microstimulator include its capabilities to generate a wide range of waveforms and to combine up to four different programmable frequencies in each wave train. By using a forward error detection and correction communication protocol, the reliability of the implant is increased. The chip has been designed for structural testability by means of a scan-based test approach and uses circuit techniques to reduce power consumption and ensure long-term stability.
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Affiliation(s)
- K Arabi
- Department of Electrical and Computer Engineering, Ecole Polytechnique de Montreal, Canada
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Walter JS, Wheeler JS, Dunn RB. Dynamic bulbocavernosus reflex: dyssynergia evaluation following SCI. THE JOURNAL OF THE AMERICAN PARAPLEGIA SOCIETY 1994; 17:140-5. [PMID: 7964709 DOI: 10.1080/01952307.1994.11735924] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
High urethral resistance caused by detrusor-sphincter dyssynergia (DSD) occurs following spinal cord injury (SCI) and results in poor voiding. A major pelvic floor reflex that may be involved in DSD is the bulbocavernosus reflex (BC) and evaluation of this reflex during the micturition cycle may provide additional information regarding this role. The periodic BC observed during micturition via cystometry is described as a dynamic bulbocavernosus reflex (DBC). The DBC was induced in upper motor neuron SCI patients using periodic dorsal penile nerve stimulation; the evoked reflex response was recorded with an anal sphincter pressure sensing balloon. Stimulation of 15-50 mA was applied at the base and dorsal side of the penis with surface electrodes, pulsed at a rate of 0.25 Hz. By applying the stimulation during cystometry, the BC reflex could be evaluated throughout the entire micturition cycle. Results showed that the DBC increased during bladder filling and bladder contractions. These findings indicate that an enhanced BC reflex is a major factor causing increased urethral resistance during micturition.
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Affiliation(s)
- J S Walter
- Micturition Dysfunction Laboratory, Hines DVA Hospital, IL 60141
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Wheeler JS, Walter JS, Sibley P. Management of incontinent SCI patients with penile stimulation: preliminary results. THE JOURNAL OF THE AMERICAN PARAPLEGIA SOCIETY 1994; 17:55-9. [PMID: 8064287 DOI: 10.1080/01952307.1994.11735917] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We investigated dorsal penile stimulation for control of incontinence in nine spinal cord impaired (SCI) patients, using a battery-powered home-use stimulator connected to surface electrodes (Unipatch). The efficacy of the penile stimulation was assessed by urodynamic evaluation (NL-2, LifeTech) and surface electrodes (Unipatch); baseline and repeat cystometries (CMG) with and without stimulation were done. Stimulation for home use was begun at threshold parameters for inducing perineal contractions and, after two weeks, was adjusted based upon results. Two subjects successfully completed the study and became continent. One of these patient's CMG demonstrated hyperreflexia and his volume increased from 110 ml to 150 ml after the stimulation protocol. The most effective stimulating parameters were 5 pps, 250 microsec, pulse width and 40 ma current. The other patient also had a hyperreflexic bladder and improved on the protocol. The remaining seven patients did not complete the study for several reasons. Three patients had CMG's that demonstrated areflexia. Stimulation did not alter their bladder function and they dropped out of the program. Three other subjects withdrew because of bothersome sensations even at subthreshold levels and they complained that the technique was cumbersome. Finally, one patient with significant hyperreflexia and incontinence withdrew after trying unsuccessfully and diligently for 10 days. Our encouraging results in two patients with hyperreflexic bladders and decreased sensation suggest that this modality may be effective in this patient group.
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Affiliation(s)
- J S Wheeler
- Department of Urology, Loyola University Medical Center, Maywood, Illinois 60153
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Walter JS, Wheeler JS, Cogan SF, Plishka M, Riedy LW, Wurster RD. Evaluation of direct bladder stimulation with stainless steel woven eye electrodes. J Urol 1993; 150:1990-6. [PMID: 8230551 DOI: 10.1016/s0022-5347(17)35952-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Encouraged by recent clinical reports of micturition induced in patients by direct bladder stimulation, we conducted a study of optimum methods of direct bladder stimulation. During surgery six male cats received eight large surface-area woven eye electrodes sutured to the bladder wall serosa, four on the bladder dome and four adjacent to the trigone area. Two additional small surface-area single knot electrodes were sutured in the trigone area. Suprapubic and intraperitoneal tubes were placed for pressure recording and bladder filling. Leg and pelvic floor EMG electrodes were also used for tethered recordings. One to eight weeks after surgery, optimum stimulation methods were evaluated as the animal freely moved about a urodynamic recording cage. Electrodes in the trigone region were more effective than electrodes on the dome and induced bladder contractions and voiding similar to spontaneously induced voiding with bladder filing. Large surface area, woven eye electrodes, composed of multistranded 316LVM stainless steel wire, were more effective than smaller surface area single knot electrodes. High stimulating frequencies (40 Hz) were better than lower frequencies (10 to 20 Hz), and a 1 millisecond pulse duration was optimal. Pulsing with stimulating currents from 10 to 25 mA induced effective bladder contractions with voiding when applied for 3 seconds. However, lower currents using longer stimulation periods were also effective. Bipolar electrodes with both electrodes on the bladder wall were superior to monopolar arrangements with the positive ground electrode along the animal's back. We concluded that in the able-bodied cat model, bladder contractile activity for micturition can be induced with direct bladder stimulation and with little discomfort. An effective stimulation protocol consists of capacitor-coupled monophasic pulses with large surface area bipolar electrodes in the trigone region. Stimulating parameters of 40 Hz, 1 msec., 10 to 25 mA applied for 3 seconds were optimal. In addition, based on corrosion resistance observations, the electrodes are quite suitable for long-term studies.
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Affiliation(s)
- J S Walter
- Hines VA Hospital, Rehabilitation R & D Center, Illinois
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