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Dias N, Zhang C, Smith CP, Lai HH, Zhang Y. High-density surface electromyographic assessment of pelvic floor hypertonicity in IC/BPS patients: a pilot study. Int Urogynecol J 2020; 32:1221-1228. [PMID: 32761375 DOI: 10.1007/s00192-020-04467-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 07/23/2020] [Indexed: 11/25/2022]
Abstract
INTRODUCTION AND HYPOTHESIS To assess the feasibility of objectively assessing pelvic floor hypertonicity (PFH) in women with interstitial cystitis/bladder pain syndrome (IC/BPS) using an intra-vaginal high-density surface electromyography (HD-sEMG) probe. METHODS Seven female subjects (mean age 44 ± 13 years) with a prior diagnosis of IC/BPS were recruited. A full digital pelvic examination was administered to identify hypertonic muscles. Intra-vaginal HD-sEMG was acquired during rest. Root-mean-squared (RMS) amplitude during rest was calculated for each channel to define a hypertonicity index and hypertonic zone. Innervation zones (IZs) were identified from the bipolar mapping of decomposed HD-sEMG signals and summarized into an IZ distribution mapping. RESULTS Of the seven subjects recruited, five had normal pelvic floor muscle tone and two exhibited hypertonicity upon muscle palpation. Subjects with PFH demonstrated a higher hypertonicity index (12.6 ± 3.5 vs. 4.5 ± 1.2) in sessions 1 and 2. The hypertonic zone defined by the 64-channel RMS mapping coincided with the digital pelvic examination findings. The corresponding IZs were localized for each motor unit. The hypertonicity indices between two consecutive sessions were well correlated (CC = 0.95). CONCLUSIONS This study represents the first effort to employ intra-vaginal HD-sEMG to assess PFH in women with IC/BPS. Our results demonstrate the feasibility of HD-sEMG to provide a quantitative diagnosis of PFH and the precise localization of hypertonic muscles and IZs. The proposed HD-sEMG-based techniques provide promising tools for clinical diagnosis and treatment of PFH, such as the personalized guidance of BoNT injections.
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Affiliation(s)
- Nicholas Dias
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | - Chuan Zhang
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA
| | | | - H Henry Lai
- Department of Surgery, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Yingchun Zhang
- Department of Biomedical Engineering, University of Houston, Houston, TX, 77204, USA.
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Paskaranandavadivel N, Varghese C, Lara J, Ramachandran S, Cheng L, Holobar A, Gharibans A, Bissett I, Collinson R, Stinear C, O'Grady G. A Novel High-Density Electromyography Probe for Evaluating Anorectal Neurophysiology: Design, Human Feasibility Study, and Validation with Trans-Sacral Magnetic Stimulation. Ann Biomed Eng 2020; 49:502-514. [PMID: 32737639 DOI: 10.1007/s10439-020-02581-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 07/22/2020] [Indexed: 12/17/2022]
Abstract
Fecal incontinence (FI) substantially impairs quality of life and imparts a major socioeconomic burden. Anal sphincter injury and possibly pudendal nerve damage are considered common causes, however, current clinical methods for evaluating their function remain suboptimal. Electromyography (EMG) and pudendal nerve terminal latencies have been applied with some success, but are not considered standard practice due to uncertain accuracy and clinical value. In this study we developed and applied a novel anorectal high-density (HD) EMG probe in humans and pigs to acquire quantitative electrophysiological metrics of the anorectum. In the human trial we assessed somatic pathways and showed that EMG amplitude was greater for tight voluntary squeezes than light voluntary squeezes (0.03 ± 0.02 mV vs. 0.05 ± 0.03 mV). In a porcine model we applied trans-sacral magnetic stimulation to evoke extrinsically activated involuntary pathways and the resulting motor evoked potentials (MEP) were captured using the HD-EMG probe. The mean MEP amplitude at 50% magnetic stimulation intensity output (MSO) was significantly lower that the MEP amplitude at 85, 95 and 100% MSO (1.52 ± 0.50 mV vs. 3.10 ± 0.60 mV). In conclusion, the use of HD-EMG probe in conjunction with trans-sacral magnetic stimulation, for spatiotemporal mapping of anorectal EMG and MEP activity is anticipated to achieve new insights into FI and could offer improved diagnostic and prognostic biomarkers for anorectal dysfunction.
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Affiliation(s)
- Niranchan Paskaranandavadivel
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.
- Department of Surgery, University of Auckland, Auckland, New Zealand.
| | - Chris Varghese
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Jaime Lara
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Shasti Ramachandran
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Leo Cheng
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
- Vanderbilt University, Nashville, TN, USA
| | - Ales Holobar
- Faculty of Electrical Engineering and Computer Science, University of Maribor, Maribor, Slovenia
| | - Armen Gharibans
- Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Ian Bissett
- Department of Surgery, University of Auckland, Auckland, New Zealand
- Auckland City Hospital, Auckland, New Zealand
| | | | - Cathy Stinear
- Department of Medicine, University of Auckland, Auckland, New Zealand
| | - Gregory O'Grady
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
- Department of Surgery, University of Auckland, Auckland, New Zealand
- Auckland City Hospital, Auckland, New Zealand
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Chuang FC, Yang TH, Kuo HC. Botulinum toxin A injection in the treatment of chronic pelvic pain with hypertonic pelvic floor in women: Treatment techniques and results. Low Urin Tract Symptoms 2020; 13:5-12. [PMID: 32654386 DOI: 10.1111/luts.12334] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 04/29/2020] [Accepted: 05/22/2020] [Indexed: 11/27/2022]
Abstract
Chronic pelvic pain (CPP) is an extremely bothersome condition which leads to major effects in women's everyday life. In addition to visceral sources of pain, pelvic floor dysfunction including myofascial pain and spasm on the pelvic floor muscles causing hypertonicity are causes often overlooked. Injecting botulinum toxin type A (BoNT-A) into hypertonic pelvic floor muscles may aid the relaxation of pelvic floor musculature. The muscles that are injected in CPP treatment include the obturator internus, levator ani (pubococcygeus, iliococcygeus, and puborectalis), and coccygeus. Generally, injections can be performed tolerably with safety under conscious sedation combined with local anesthesia. Most practitioners perform BoNT-A injection of pelvic floor muscles using anatomical landmarks identified by manual palpation only. For the precise location of injection sites, some needle guidance techniques were proposed, including electromyography, electrical stimulation, ultrasound, fluoroscopy, and/or computed tomography. Side effects of BoNT-A injection in CPP are rare and self-limiting. Because of the reversible nature of BoNT-A, reinjection appears to be necessary. Increasing proof points out that BoNT-A is a promising treatment option for CPP in women. We conducted a review of published literature in Pubmed, using chronic pelvic pain in women, hypertonic pelvic floor, and botulinum toxin as the keywords. This article aims to summarize the treatment techniques and results of BoNT-A injection for hypertonic pelvic floor in women with chronic pelvic pain.
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Affiliation(s)
- Fei-Chi Chuang
- Department of Obstetrics and Gynecology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Tsai-Hwa Yang
- Department of Obstetrics and Gynecology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Hann-Chorng Kuo
- Department of Urology, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation and Tzu Chi University, Hualien, Taiwan
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Innervation zone locations distribute medially within the pectoralis major muscle during bench press exercise. J Electromyogr Kinesiol 2019; 46:8-13. [DOI: 10.1016/j.jelekin.2019.03.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 02/25/2019] [Accepted: 03/06/2019] [Indexed: 11/22/2022] Open
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Dias N, Li X, Zhang C, Zhang Y. Innervation asymmetry of the external anal sphincter in aging characterized from high-density intra-rectal surface EMG recordings. Neurourol Urodyn 2018; 37:2544-2550. [PMID: 30152548 DOI: 10.1002/nau.23809] [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: 04/04/2018] [Accepted: 07/31/2018] [Indexed: 12/17/2022]
Abstract
AIMS The innervation zone asymmetry of the external anal sphincter (EAS) has been investigated as a risk factor for the development of fecal incontinence (FI). This study aims to utilize an intra-rectal high-density surface electromyogram (HD-sEMG) recording and advanced HD-sEMG decomposition technique to characterize the effects of aging on the asymmetry of EAS functional innervation. METHODS HD-sEMG signals were recorded intra-rectally from six healthy young and seven healthy elderly women during voluntary contractions of the EAS. EMG signals were decomposed into constituent motor unit action potentials (MUAPs) and the innervation zone of each decomposed motor unit was identified. Asymmetry index (AI) was defined and calculated for all subjects. The maximum squeezing pressures of the EAS were also measured for all subjects as a comparison. RESULTS The HD-sEMG decomposition and AI calculation were successfully performed from EMG data acquired from all the subjects. The AI values were 28.7 ± 17.0% for the young group and 55.6 ± 18.8% for the elderly group. The AI and EAS contraction strength were found to be negatively correlated (P < 0.05). A two-tailed student's t-test demonstrated a significant increase in AI with age by comparison between two groups (P < 0.05). CONCLUSIONS Our work demonstrates, for the first time, that EAS functional innervation tends to become increasingly asymmetrical with advancing age, and this increase is associated with a compromised anorectal function. Results suggest that the intra-rectal HD-sEMG will serve as an advanced tool for assessing and monitoring the anorectal neuromuscular function minimally invasively under different pathophysiological conditions.
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Affiliation(s)
- Nicholas Dias
- Department of Biomedical Engineering, University of Houston, Houston, Texas
| | - Xuhong Li
- The Third Xiangya Hospital, Central South University, Changsha, China
| | - Chuan Zhang
- Department of Biomedical Engineering, University of Houston, Houston, Texas.,Guangdong Provincial Work-injury Rehabilitation Hospital, Guangzhou, China
| | - Yingchun Zhang
- Department of Biomedical Engineering, University of Houston, Houston, Texas.,Guangdong Provincial Work-injury Rehabilitation Hospital, Guangzhou, China
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6
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Zhang Y, Smith CP. Botulinum toxin to treat pelvic pain. Toxicon 2018; 147:129-133. [DOI: 10.1016/j.toxicon.2017.08.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 08/14/2017] [Accepted: 08/17/2017] [Indexed: 10/19/2022]
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Peng Y, Miller BD, Boone TB, Zhang Y. Modern Theories of Pelvic Floor Support : A Topical Review of Modern Studies on Structural and Functional Pelvic Floor Support from Medical Imaging, Computational Modeling, and Electromyographic Perspectives. Curr Urol Rep 2018; 19:9. [PMID: 29435856 DOI: 10.1007/s11934-018-0752-9] [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] [Indexed: 12/17/2022]
Abstract
PURPOSE OF REVIEW Weakened pelvic floor support is believed to be the main cause of various pelvic floor disorders. Modern theories of pelvic floor support stress on the structural and functional integrity of multiple structures and their interplay to maintain normal pelvic floor functions. Connective tissues provide passive pelvic floor support while pelvic floor muscles provide active support through voluntary contraction. Advanced modern medical technologies allow us to comprehensively and thoroughly evaluate the interaction of supporting structures and assess both active and passive support functions. The pathophysiology of various pelvic floor disorders associated with pelvic floor weakness is now under scrutiny from the combination of (1) morphological, (2) dynamic (through computational modeling), and (3) neurophysiological perspectives. This topical review aims to update newly emerged studies assessing pelvic floor support function among these three categories. RECENT FINDINGS A literature search was performed with emphasis on (1) medical imaging studies that assess pelvic floor muscle architecture, (2) subject-specific computational modeling studies that address new topics such as modeling muscle contractions, and (3) pelvic floor neurophysiology studies that report novel devices or findings such as high-density surface electromyography techniques. We found that recent computational modeling studies are featured with more realistic soft tissue constitutive models (e.g., active muscle contraction) as well as an increasing interest in simulating surgical interventions (e.g., artificial sphincter). Diffusion tensor imaging provides a useful non-invasive tool to characterize pelvic floor muscles at the microstructural level, which can be potentially used to improve the accuracy of the simulation of muscle contraction. Studies using high-density surface electromyography anal and vaginal probes on large patient cohorts have been recently reported. Influences of vaginal delivery on the distribution of innervation zones of pelvic floor muscles are clarified, providing useful guidance for a better protection of women during delivery. We are now in a period of transition to advanced diagnostic and predictive pelvic floor medicine. Our findings highlight the application of diffusion tensor imaging, computational models with consideration of active pelvic floor muscle contraction, high-density surface electromyography, and their potential integration, as tools to push the boundary of our knowledge in pelvic floor support and better shape current clinical practice.
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Affiliation(s)
- Yun Peng
- Department of Biomedical Engineering, Cullen College of Engineering, University of Houston, 360 HBS Building, 4811 Calhoun Rd., Houston, TX, 77004, USA
| | - Brandi D Miller
- Department of Urology, Houston Methodist Hospital, Houston, TX, 77030, USA
| | - Timothy B Boone
- Department of Urology, Houston Methodist Hospital, Houston, TX, 77030, USA
| | - Yingchun Zhang
- Department of Biomedical Engineering, Cullen College of Engineering, University of Houston, 360 HBS Building, 4811 Calhoun Rd., Houston, TX, 77004, USA.
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Shiraz A, Leaker B, Mosse CA, Solomon E, Craggs M, Demosthenous A. Design of sEMG assembly to detect external anal sphincter activity: a proof of concept. Physiol Meas 2017; 38:L17-L27. [PMID: 28901946 DOI: 10.1088/1361-6579/aa8c52] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Conditional trans-rectal stimulation of the pudendal nerve could provide a viable solution to treat hyperreflexive bladder in spinal cord injury. A set threshold of the amplitude estimate of the external anal sphincter surface electromyography (sEMG) may be used as the trigger signal. The efficacy of such a device should be tested in a large scale clinical trial. As such, a probe should remain in situ for several hours while patients attend to their daily routine; the recording electrodes should be designed to be large enough to maintain good contact while observing design constraints. The objective of this study was to arrive at a design for intra-anal sEMG recording electrodes for the subsequent clinical trials while deriving the possible recording and processing parameters. APPROACH Having in mind existing solutions and based on theoretical and anatomical considerations, a set of four multi-electrode probes were designed and developed. These were tested in a healthy subject and the measured sEMG traces were recorded and appropriately processed. MAIN RESULTS It was shown that while comparatively large electrodes record sEMG traces that are not sufficiently correlated with the external anal sphincter contractions, smaller electrodes may not maintain a stable electrode tissue contact. It was shown that 3 mm wide and 1 cm long electrodes with 5 mm inter-electrode spacing, in agreement with Nyquist sampling, placed 1 cm from the orifice may intra-anally record a sEMG trace sufficiently correlated with external anal sphincter activity. SIGNIFICANCE The outcome of this study can be used in any biofeedback, treatment or diagnostic application where the activity of the external anal sphincter sEMG should be detected for an extended period of time.
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Affiliation(s)
- Arsam Shiraz
- Department of Electronic and Electrical Engineering, University College London, London, United Kingdom
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9
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Peng Y, He J, Khavari R, Boone TB, Zhang Y. Functional mapping of the pelvic floor and sphincter muscles from high-density surface EMG recordings. Int Urogynecol J 2016; 27:1689-1696. [PMID: 27193113 DOI: 10.1007/s00192-016-3026-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 04/11/2016] [Indexed: 12/17/2022]
Abstract
INTRODUCTION AND HYPOTHESIS Knowledge of the innervation of pelvic floor and sphincter muscles is of great importance to understanding the pathophysiology of female pelvic floor dysfunctions. This report presents our high-density intravaginal and intrarectal electromyography (EMG) probes and a comprehensive innervation zone (IZ) imaging technique based on high-density EMG readings to characterize the IZ distribution. METHODS Both intravaginal and intrarectal probes are covered with a high-density surface electromyography electrode grid (8 × 8). Surface EMG signals were acquired in ten healthy women performing maximum voluntary contractions of their pelvic floor. EMG decomposition was performed to separate motor-unit action potentials (MUAPs) and then localize their IZs. RESULTS High-density surface EMG signals were successfully acquired over the vaginal and rectal surfaces. The propagation patterns of muscle activity were clearly visualized for multiple muscle groups of the pelvic floor and anal sphincter. During each contraction, up to 218 and 456 repetitions of motor units were detected by the vaginal and rectal probes, respectively. MUAPs were separated with their IZs identified at various orientations and depths. CONCLUSIONS The proposed probes are capable of providing a comprehensive mapping of IZs of the pelvic floor and sphincter muscles. They can be employed as diagnostic and preventative tools in clinical practices.
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Affiliation(s)
- Yun Peng
- Department of Biomedical Engineering, Cullen College of Engineering, University of Houston, 360 HBS Building, 4811 Calhoun Rd., Houston, TX, 77004, USA
| | - Jinbao He
- School of Electronic and Information Engineering, Ningbo University of Technology, Ningbo, China
| | - Rose Khavari
- Department of Urology, Houston Methodist Hospital and Research Institute, Houston, TX, 77030, USA
| | - Timothy B Boone
- Department of Urology, Houston Methodist Hospital and Research Institute, Houston, TX, 77030, USA
| | - Yingchun Zhang
- Department of Biomedical Engineering, Cullen College of Engineering, University of Houston, 360 HBS Building, 4811 Calhoun Rd., Houston, TX, 77004, USA.
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Jahanmiri-Nezhad F, Barkhaus PE, Rymer WZ, Zhou P. Innervation zones of fasciculating motor units: observations by a linear electrode array. Front Hum Neurosci 2015; 9:239. [PMID: 26029076 PMCID: PMC4429247 DOI: 10.3389/fnhum.2015.00239] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 04/13/2015] [Indexed: 12/13/2022] Open
Abstract
This study examines the innervation zone (IZ) in the biceps brachii muscle in healthy subjects and those with amyotrophic lateral sclerosis (ALS) using a 20-channel linear electromyogram (EMG) electrode array. Raster plots of individual waveform potentials were studied to estimate the motor unit IZ. While this work mainly focused on fasciculation potentials (FPs), a limited number of motor unit potentials (MUPs) from voluntary activity of 12 healthy and seven ALS subjects were also examined. Abnormal propagation of MUPs and scattered IZs were observed in fasciculating units, compared with voluntarily activated MUPs in healthy and ALS subjects. These findings can be related to muscle fiber reinnervation following motor neuron degeneration in ALS and the different origin sites of FPs compared with voluntary MUPs.
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Affiliation(s)
- Faezeh Jahanmiri-Nezhad
- Department of Bioengineering, University of Illinois at Chicago Chicago, IL, USA ; Single Motor Unit Lab, Sensory Motor Performance Program, Rehabilitation Institute of Chicago Chicago, IL, USA
| | - Paul E Barkhaus
- Department of Neurology, Medical College of Wisconsin and the Milwaukee Veterans Administration Medical Center Milwaukee, WI, USA
| | - William Z Rymer
- Single Motor Unit Lab, Sensory Motor Performance Program, Rehabilitation Institute of Chicago Chicago, IL, USA ; Department of Physical Medicine and Rehabilitation, Northwestern University Chicago, IL, USA
| | - Ping Zhou
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center and TIRR Memorial Hermann Research Center Houston, TX, USA ; Biomedical Engineering Program, University of Science and Technology of China Hefei, China
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Heesakkers J, Gerretsen R, Izeta A, Sievert KD, Farag F. Circumferential urinary sphincter surface electromyography: A novel diagnostic method for intrinsic sphincter deficiency. Neurourol Urodyn 2014; 35:186-91. [DOI: 10.1002/nau.22711] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 10/24/2014] [Indexed: 11/12/2022]
Affiliation(s)
- John Heesakkers
- Department of Urology; Radboud University Medical Centre; Nijmegen The Netherlands
| | - Reza Gerretsen
- Department of Forensic Medicine; Netherlands Forensic Institute; The Hague The Netherlands
| | - Ander Izeta
- Instituto Biodonostia; Hospital Universitario Donostia; San Sebastian Spain
| | | | - Fawzy Farag
- Department of Urology; Radboud University Medical Centre; Nijmegen The Netherlands
- Department of Urology; Sohag University Hospital; Sohag Egypt
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12
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Cescon C, Riva D, Začesta V, Drusany-Starič K, Martsidis K, Protsepko O, Baessler K, Merletti R. Effect of vaginal delivery on the external anal sphincter muscle innervation pattern evaluated by multichannel surface EMG: results of the multicentre study TASI-2. Int Urogynecol J 2014; 25:1491-9. [PMID: 24687366 DOI: 10.1007/s00192-014-2375-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Accepted: 03/10/2014] [Indexed: 10/25/2022]
Abstract
INTRODUCTION AND HYPOTHESIS A correlation exists between external anal sphincter (EAS) damage during birth and the subsequent development of fecal incontinence. This study evaluated the effect of delivery-related trauma on EAS innervation by means of intra-anal EMG performed with a rectal probe with 16 silver electrodes equally spaced along the circumference, before and after delivery. METHODS Pre-partum EMG measurements were performed on 511 women, by nine clinical partners from five European countries at the 28th to 34th gestational weeks and the 6th to 8th post-delivery weeks; 331 women returned, after delivery, for the second test. The innervation zones (IZ) of EAS single motor units were identified by means of an EMG decomposition algorithm. RESULTS The subjects were divided into four groups according to the delivery mode (Caesarean, vaginal with no evident damage, spontaneous lacerations and episiotomies). The number of IZs before and after delivery was compared. In the 82 women who underwent right mediolateral episiotomy, a statistically significant reduction of IZs was observed, after delivery, in the right ventral quadrant of the EAS (side of the episiotomy). Women who had Caesarean section, spontaneous lacerations or lack of evident damage did not present any significant change in the innervation pattern. CONCLUSIONS Right episiotomy reduces the number of IZs on the right-ventral side of the EAS. The fast and reliable test proposed indicates the sphincter innervation pattern before delivery and helps obstetricians to evaluate the risks and to choose the preferred side of the episiotomy, if deemed necessary at the time of delivery.
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Affiliation(s)
- Corrado Cescon
- Laboratory for Engineering of the Neuromuscular System, Department of Electronics, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino, 10129, Italy
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Characterization of the motor units of the external anal sphincter in pregnant women with multichannel surface EMG. Int Urogynecol J 2014; 25:1097-103. [PMID: 24623258 DOI: 10.1007/s00192-014-2356-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Accepted: 02/07/2014] [Indexed: 10/25/2022]
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Nowakowski M, Tomaszewski KA, Herman RM, Sałówka J, Romaniszyn M, Rubinkiewicz M, Walocha JA. Developing a new electromyography-based algorithm to diagnose the etiology of fecal incontinence. Int J Colorectal Dis 2014; 29:747-54. [PMID: 24743845 PMCID: PMC4028542 DOI: 10.1007/s00384-014-1859-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/02/2014] [Indexed: 02/04/2023]
Abstract
PURPOSE For surface electromyography (sEMG) to become widely used in fecal incontinence (FI) etiology assessment, one would have to create a simple, step-by-step, computer-aided, electromyography-based algorithm that would become the basis for a computer-aided diagnosis (CAD) system. Thus, the aim of this work was to develop such an algorithm. METHODS Each patient included in the study underwent a structured medical interview, a general physical examination, and a proctological examination. Patients that scored more than 10 points on the fecal incontinence severity index (FISI) underwent further tests that included rectoscopy, anorectal manometry, transanal ultrasonography, multichannel sEMG, and assessment of anal reflexes. Patients with fully diagnosed FI were included into the study group. The control group consisted of healthy volunteers that scored five or less points on the FISI and had no known anal sphincters dysfunction. RESULTS Forty-nine patients were qualified to the study group (age ± SD 58.9 ± 13.8). The control group was number- and gender-matched (age ± SD 45.4 ± 15.1). The sensitivity and specificity of classification tree number I, to diagnose neurogenic FI, were 89.5 and 86 %, respectively. For patients with idiopathic FI, these values were 82 and 91 %, respectively. The sensitivity and specificity of classification tree number III, to diagnose neurogenic FI, were 84 and 78 %, respectively. For patients with idiopathic FI, these values were 78 and 87 %, respectively. CONCLUSIONS The relative simplicity and low classification costs allow to assume that algorithms based on classification trees I and III will serve to be the basis for a FI etiology CAD system.
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Affiliation(s)
- Michał Nowakowski
- Department of Medical Education, Jagiellonian University Medical College, Krakow, Poland
| | | | - Roman M. Herman
- Department of Clinical and Experimental Surgery, Jagiellonian University Medical College, Krakow, Poland
| | - Jerzy Sałówka
- Department of General Surgery, Stanley Dudrick Memorial Hospital, Skawina, Poland
| | - Michał Romaniszyn
- Department of General Surgery, G. Narutowicz Specialist City Hospital, Krakow, Poland
| | - Mateusz Rubinkiewicz
- Department of Medical Education, Jagiellonian University Medical College, Krakow, Poland
| | - Jerzy A. Walocha
- Department of Anatomy, Jagiellonian University Medical College, Krakow, Poland
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Barbero M, Gatti R, Lo Conte L, Macmillan F, Coutts F, Merletti R. Reliability of surface EMG matrix in locating the innervation zone of upper trapezius muscle. J Electromyogr Kinesiol 2011; 21:827-33. [PMID: 21752668 DOI: 10.1016/j.jelekin.2011.05.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 04/15/2011] [Accepted: 05/27/2011] [Indexed: 10/18/2022] Open
Abstract
The identification of the motor unit (MU) innervation zone (IZ) using surface electromyographic (sEMG) signals detected on the skin with a linear array or a matrix of electrodes has been recently proposed in the literature. However, an analysis of the reliability of this procedure and, therefore, of the suitability of the sEMG signals for this purpose has not been reported. The purpose of this work is to describe the intra and inter-rater reliability and the suitability of surface EMG in locating the innervation zone of the upper trapezius muscle. Two operators were trained on electrode matrix positioning and sEMG signal analysis. Ten healthy subjects, instructed to perform a series of isometric contractions of the upper trapezius muscle participated in the study. The two operators collected sEMG signals and then independently estimated the IZ location through visual analysis. Results showed an almost perfect agreement for intra-rater and inter-rater reliability. The constancy of IZ location could be affected by the factors reflecting the population of active MUs and their IZs, including: the contraction intensity, the acquisition period analyzed, the contraction repetition. In almost all cases the IZ location shift due to these factors did not exceed 4mm. Results generalization to other muscles should be made with caution.
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Affiliation(s)
- Marco Barbero
- School of Health Sciences, Queen Margaret University, Edinburgh, UK.
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16
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Cescon C, Mesin L, Nowakowski M, Merletti R. Geometry assessment of anal sphincter muscle based on monopolar multichannel surface EMG signals. J Electromyogr Kinesiol 2010; 21:394-401. [PMID: 21130667 DOI: 10.1016/j.jelekin.2010.11.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 10/09/2010] [Accepted: 11/05/2010] [Indexed: 11/17/2022] Open
Abstract
Anatomical studies on the external anal sphincter (EAS) indicate that superficial muscle fibres are circular at low depth within the anal canal. A more complex geometry of the fibres is documented for increasing depth within the muscle and along the anal canal. Monopolar intra-anal EMG signals recorded using an array of electrodes placed in circular direction have no common mode components if the muscle fibres are circular, with constant depth within the muscle and parallel to the detection array. Thus, the presence of common mode signals may provide indications about the geometry of muscle fibres of EAS. Intra-anal EMG signals were recorded from EAS of 12 subjects using an anal probe carrying three circumferential arrays of 16 electrodes at three depths within the anal canal. Contribution of common mode components in single MUAPs was lower for MUs located superficially in the muscle (Pearson correlation coefficient: R=-0.75, p≪0.001) and at a lower depth within the anal canal (non-parametric one way Kruskal-Wallis ANOVA, Χ=17.3, p<0.001), in line with EAS anatomy. A large contribution of common mode components was found in the interference signal, suggesting that the signal receives contributions from far, large muscles (e.g. puborectalis, glutei).
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Affiliation(s)
- Corrado Cescon
- Laboratorio di Ingegneria del Sistema Neuromuscolare (LISiN), Dipartimento di Elettronica, Politecnico di Torino, Torino, Italy.
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17
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Enck P, Franz H, Davico E, Mastrangelo F, Mesin L, Merletti R. Repeatability of innervation zone identification in the external anal sphincter muscle. Neurourol Urodyn 2010; 29:449-57. [PMID: 19634169 DOI: 10.1002/nau.20749] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AIMS Knowledge of the distribution of the innervation zones (IZs) of the external anal sphincter (EAS) may be useful for preventing anal sphincter incompetence during vaginal delivery. A method proposed for the automatic estimation of the distribution of IZs of EAS from high-density surface electromyography (EMG) was evaluated for repeatability in continent volunteers. METHODS In 13 healthy female subjects (age: 35 +/- 11 years) surface EMG signals were acquired using an anal probe with three circumferential electrode arrays (of 16 contacts each) at different depths within the anal canal (15 mm distance between the centers of adjacent arrays), during four independent experimental sessions. Three maximal voluntary contractions (MVCs) of 10 sec were performed for each session for a total of 12 contractions per subject. Repeatability of the estimation of the distribution of IZ was tested by evaluating the coefficient of multiple correlations (CMC) between the IZ distributions estimated from the signals recorded from each subject. RESULTS A high repeatability (CMC > 0.8) was found comparing IZ distributions estimated from signals recorded by each array within the same session. A slightly lower value was obtained considering signals recorded during different sessions (CMC > 0.7), but a higher value (CMC > 0.8) was obtained after aligning the estimated IZ distributions. The realignment compensates for the operator's error in repositioning the probe in the same position during different sessions. CONCLUSION This result justifies clinical studies using high-density surface EMG in routine examinations, providing information about IZs of EAS and assessing the possibilities of preventing neuronal trauma during vaginal delivery.
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Affiliation(s)
- Paul Enck
- Department of Internal Medicine VI, University Hospitals Tübingen, Tübingen, Germany.
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18
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Mesin L, Gazzoni M, Merletti R. Automatic localisation of innervation zones: A simulation study of the external anal sphincter. J Electromyogr Kinesiol 2009; 19:e413-21. [PMID: 19269857 DOI: 10.1016/j.jelekin.2009.02.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Revised: 11/17/2008] [Accepted: 02/02/2009] [Indexed: 10/21/2022] Open
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Cescon C, Bottin A, Fernandez Fraga XL, Azpiroz F, Merletti R. Detection of individual motor units of the puborectalis muscle by non-invasive EMG electrode arrays. J Electromyogr Kinesiol 2008; 18:382-9. [PMID: 17291780 DOI: 10.1016/j.jelekin.2006.11.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2006] [Revised: 11/08/2006] [Accepted: 11/14/2006] [Indexed: 11/21/2022] Open
Abstract
PURPOSE The purpose of the study was to demonstrate that anatomical features of individual motor units of the puborectalis muscle can be detected with non-invasive electromyography (EMG) and to evaluate differences in electrophysiological properties of the puborectalis muscles in a small group of healthy and pathologic subjects. METHODS Multichannel EMG was recorded by means of a flexible probe applied on the gloved index finger and carrying an array of eight equally spaced (1.15 mm) electrodes. A multichannel EMG amplifier provided seven outputs corresponding to the pairs of adjacent electrodes. Tests were performed in three different positions (dorsal, left and right) over the puborectalis muscle on 20 subjects (nine healthy, seven constipated and four incontinent patients). Motor unit action potentials (MUAPs) generated at the innervation zone of a MU and propagating along the muscle fibers generated repetitive characteristic patterns on the seven output channels allowing identification of anatomical features of the motor units. RESULTS MUAPs were observed travelling in either one or both directions with the array in dorsal position, and mainly in ventral-to-dorsal direction in either lateral position. MUAP amplitude was lower in constipated and incontinent patients with respect to healthy subjects. The conduction velocity estimated on the identified MUAPs was lower for constipated patients with respect to healthy subjects suggesting different mechanical properties of the active motor units. CONCLUSIONS This technique allows the extraction of relevant information about the anatomical features (innervation zone position and overlapping of motor unit branches) of the puborectalis muscle and its electrophysiological properties and maybe can be applied as an novel methodology for assessing the anorectal function in patients.
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Affiliation(s)
- Corrado Cescon
- Laboratory for Engineering of the Neuromuscular System (LISiN), Department of Electronics, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
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20
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Abstract
Pelvic floor muscles (PFM) are intimately involved in function of lower urinary tract, the anorectum and sexual functions, therefore their neural control transcends the primarily important somatic innervation of striated muscle, as they are directly involved in "visceral activity". Neural control of pelvic organs is affected by a unique co-ordination of somatic and autonomic motor nervous systems. Visceral and somatic sensory fibres supply sensory information from pelvic organs; their input influences through central integrative mechanisms also pelvic floor muscle activity. Anatomically, somatic afferent and efferent nerves of the sacral cord segments, reflexly integrated at the spinal cord and brainstem level, conduct neural control of PFM. The inputs from several higher centres influence the complex reflex control and are decisive for voluntary control, and for socially adapted behaviour related to excretory functions.
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Affiliation(s)
- Paul Enck
- Department of Internal Medicine VI, University Hospitals Tübingen, Psychosomatic Medicine, Osianderstr. 5, 72076 Tübingen, Germany.
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Bottin A, Cescon C, Nowakowski M, Herman RM. Non-invasive assessment of the gracilis muscle by means of surface electromyography electrode arrays. J Surg Res 2006; 134:265-9. [PMID: 16580693 DOI: 10.1016/j.jss.2006.02.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2005] [Revised: 01/25/2006] [Accepted: 02/06/2006] [Indexed: 11/16/2022]
Abstract
PURPOSE The purpose of the study was the non-invasive investigation of the innervation zone (IZ) location of the gracilis muscle of both thighs by means of surface electromyography (EMG). MATERIALS AND METHODS Multichannel EMG signals were detected by means of a flexible array of 16 equally spaced silver bar electrodes. Tests were performed on both gracilis muscles on 15 subjects. Motor unit (MU) action potentials were visually identified and extracted. The locations of the IZs of the recognized MUs were statistically analyzed to find significant differences between the subjects and between the right and left muscle of each subject. RESULTS AND CONCLUSIONS A statistically significant difference was found between the gracilis IZ position in the two sides, with more proximal IZs on the left side. This difference suggests a possible role of surface EMG in preoperative evaluation of patients prepared for the dynamic graciloplasty procedure. This test would provide an objective criterion for the choice of the gracilis muscle to be transposed with the highest probability of success.
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Affiliation(s)
- Andrea Bottin
- Laboratory for Engineering of the Neuromuscular System (LISiN), Department of Electronics, Politecnico di Torino, Italy
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Enck P, Hinninghofen H, Merletti R, Azpiroz F. The external anal sphincter and the role of surface electromyography. Neurogastroenterol Motil 2005; 17 Suppl 1:60-7. [PMID: 15836456 DOI: 10.1111/j.1365-2982.2005.00660.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Assessment of the neuronal control of the external anal sphincter (EAS) has long been restricted to investigating patients with defecation disorders by invasive tools such as needle electromyography (EMG), while less invasive techniques have been regarded as non-suitable for diagnostic purposes. Multichannel surface EMG by means of electrode arrays applied to anal sphincter muscle records and identifies individual motor unit action potentials, their place of origin along the circumference, their repetitive firing frequency, and their progression along the muscle fibres at different levels within the anal canal. These data shed doubts on conventional knowledge about the anatomy of the EAS muscle, and confirms new concepts of anatomical differences between gender. This may eventually be transferred to a new understanding of the role of symmetry and asymmetry of pelvic floor innervation and its role in the pathogenesis of fecal incontinence.
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Affiliation(s)
- P Enck
- Department of Internal Medicine VI, University Hospitals Tübingen, Germany.
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