Centre for Clinical Research Excellence in Spinal Pain, Injury and Health, School of Health and Rehabilitation Sciences, The University of Queensland, Queensland, Brisbane, Australia.
Neurourol Urodyn. 2012 Jan;31(1):36-43. doi: 10.1002/nau.21178. Epub 2011 Jul 20.
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).
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 nasogastric pressure catheter). Participants performed four tasks that challenged postural control in standing (single and repetitive arm movement, stepping and load catching).
IAP amplitude and SUS activity were linearly correlated during repetitive arm movement (R(2): 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.
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.
男性横纹尿道括约肌（SUS）的功能存在争议。目前的证据仅限于仰卧位时使用同心针电极进行肌电图（EMG）记录。为了了解 SUS 的功能，需要使用新的记录技术在动态任务中研究 SUS 的 EMG 活动。本研究的目的是评估 SUS 在静息和动态任务期间的 EMG 活动的时相和幅度，这些任务通过增加腹内压（IAP）来挑战控尿。
对 5 名年龄在 25-39 岁的健康男性进行了研究。测量包括 SUS、肛门括约肌（AS）和腹横肌（TrA）EMG 以及 IAP（通过鼻胃管压力导管记录）。参与者进行了四项挑战站立姿势控制的任务（单臂和重复手臂运动、跨步和负载捕捉）。
在重复手臂运动期间，IAP 幅度和 SUS 活动呈线性相关（R²：0.67-0.88）。在跨步时，SUS 的 EMG 起始先于 IAP 的增加，但随后迅速进行手臂运动。当躯干意外受力时，SUS 的起始通常跟随 IAP 的增加。由于样本量较小，仅对年轻男性进行了测试。未来的研究可能会调查健康的老年男性或患有某些疾病的男性。
数据表明，SUS 活动与 IAP 成比例增加。这证明了 SUS 在 IAP 增加时有助于控尿，并且躯干的姿势控制涉及到该肌肉的激活。
