Comparative study of the motor unit potentials of the external urethral sphincter, anal sphincter, and bulbocavernosus muscle in normal men

Fanciullacci, F.; Kokodoko, A.; Garavaglia, P.; Galli, M.; Sandri, S; Zanollo, A

doi:10.1002/nau.1930060202

Cited by 13 publications

(6 citation statements)

References 4 publications

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“…However, most methods to assess the function or dysfunction of the SUS are highly invasive [e.g. needle electromyography (EMG) , intra‐urethral surface EMG , urethral pressure) and impractical for investigation of SUS function in clinical populations, or in large‐scale studies of healthy populations. Although changes in muscle morphology and tissue displacement observed with non‐invasive B‐mode ultrasonography (US) can be used to infer activation of the SUS and other pelvic floor muscles , it does not provide information on the tension/stress developed within the individual peri‐urethral muscles during contraction.…”

Section: Introductionmentioning

confidence: 99%

Application of shear‐wave elastography to estimate the stiffness of the male striated urethral sphincter during voluntary contractions

et al. 2016

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ObjectivesTo investigate whether increases in stiffness can be detected in the anatomical region associated with the striated urethral sphincter (SUS) during voluntary activation using shear-wave elastography (SWE); to identify the location and area of the stiffness increase relative to the point of greatest dorsal displacement of the mid urethra (i.e. SUS); and to determine the relationship between muscle stiffness and contraction intensity. Subjects and MethodsIn all, 10 healthy men participated. A linear ultrasound (US) transducer was placed mid-sagittal on the perineum adjacent to a pair of electromyography electrodes that recorded nonspecific pelvic floor muscle activity. Stiffness in the area expected to contain the SUS was estimated via US SWE at rest and during voluntary pelvic floor muscles contractions to 5%, 10% and 15% maximum. Still image frames were exported for each repetition and analysed with software that detected increases in stiffness above 150% of the resting stiffness. ResultsPelvic floor muscle contraction elicited an increase in stiffness above threshold within the region expected to contain the SUS for all participants and contraction intensities. The mean (SD) ventral-dorsal distance between the centre of the stiffness area and region of maximal motion of the midurethra (caused by SUS contraction) was 5.6 (1.8), 6.2 (0.8), and 5.8 (0.7) mm for 5%, 10% and 15% maximal voluntary contraction, respectively. Greater pelvic floor muscle contraction intensity resulted in a concomitant increase in stiffness, which differed between contraction intensities (5% vs 10%, P < 0.001; 5% vs 15%, P < 0.001; 10% vs 15%, P = 0.003). ConclusionVoluntary contraction of the pelvic floor muscles in men is associated with an area of stiffness increase measured with SWE, which concurs with the expected location of the SUS. The increase in stiffness occurred in association with an increase in perineal surface electromyography activity, providing evidence that stiffness amplitude relates to general pelvic floor muscle contraction intensity. Future applications of SWE may include investigations of patient populations in which dysfunction of the SUS is thought to play an important role, or investigation of the effect of rehabilitation programmes that target this muscle.

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Section: Introductionmentioning

confidence: 99%

Application of shear‐wave elastography to estimate the stiffness of the male striated urethral sphincter during voluntary contractions

et al. 2016

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“…In previous EMG studies, different insertions were proposed. Investigators have described perianal insertion at the 2:00 position, 6 insertions 1 cm outward from the anal orifice 7 and 1-1.5 cm from the anal verge, 17 and insertions just adjacent to 1 and at the mucocutaneous junction. 11 None of the investigators described the depth of the insertion; therefore, it is not possible to ascertain which parts of the muscle were examined.…”

Section: Discussionmentioning

confidence: 98%

Standardization of anal sphincter EMG: Technique of needle examination

et al. 1999

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“…Concentric needle EMG recordings show tonic SUS activity at rest in men16 and women5, 17 in supine, and in animals 18. Tonic firing has been used to confirm electrode placement 5, 16.…”

Section: Discussionmentioning

confidence: 99%

“…Concentric needle EMG recordings show tonic SUS activity at rest in men16 and women5, 17 in supine, and in animals 18. Tonic firing has been used to confirm electrode placement 5, 16. Transurethral surface electrodes are considered less sensitive to SUS EMG compared to needles in rats18 and healthy supine females 5.…”

Section: Discussionmentioning

confidence: 99%

Activation of the striated urethral sphincter to maintain continence during dynamic tasks in healthy men

Stafford

Ashton‐Miller

Sapsford

et al. 2011

Neurourology and Urodynamics

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Aims Function of the striated urethral sphincter (SUS) in men is debated. Current evidence is limited to electromyographic (EMG) recordings made with concentric needle electrodes in supine. Understanding of SUS function requires investigation of SUS EMG activity using new recording techniques in dynamic tasks. The aim of this study was to evaluate timing and amplitude of SUS EMG at rest and during dynamic tasks that challenge continence by increasing intra-abdominal pressure (IAP). Methods Investigative study of five healthy men aged 25–39 years. Measurements included SUS, anal sphincter (AS) and transversus abdominus (TrA) EMG, and IAP (recorded with a naso-gastric pressure catheter). Participants performed four tasks that challenged postural control in standing (single and repetitive arm movement, stepping and load catching). Results IAP amplitude and SUS activity were linearly correlated during repetitive arm movement (R2: 0.67–0.88). During stepping SUS EMG onset preceded the IAP increase, but followed it with rapid arm movements. When the trunk was loaded unpredictably onset of SUS generally followed the increase in IAP. The modest sample size meant only younger men were tested. Future studies might investigate healthy older men or those with certain pathologies. Conclusions Data show that SUS activity increases proportionally with IAP. This provided evidence that SUS contributes to continence when IAP is increased, and that postural control of the trunk involves activation of this muscle.

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Comparative study of the motor unit potentials of the external urethral sphincter, anal sphincter, and bulbocavernosus muscle in normal men

Cited by 13 publications

References 4 publications

Application of shear‐wave elastography to estimate the stiffness of the male striated urethral sphincter during voluntary contractions

Application of shear‐wave elastography to estimate the stiffness of the male striated urethral sphincter during voluntary contractions

Standardization of anal sphincter EMG: Technique of needle examination

Activation of the striated urethral sphincter to maintain continence during dynamic tasks in healthy men

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