ROLE OF PUBORECTALIS MUSCLE IN FECAL CONTINENCE

描述(由申请人提供)：大便失禁是一种主要的健康危害，对生活质量有重大影响。它在社区中的患病率为2%至7%，在美国50岁以上的成年人中有高达15%的人受到影响。大便失禁的病理生理学还不是很清楚。我们的工作重点是更好地定义肛门括约肌功能。具体地说，我们将研究耻骨直肠肌(PRM)在肛门控制机制中的作用。肛门内括约肌(IAS)和肛门外括约肌(EAS)的肌纤维呈环形排列。另一方面，PRM是一块“U”形肌肉，两端连接在耻骨的前面。目前还不知道PRM肌肉在休息或挤压时是否会对肛管压力产生影响。我们使用三维超声和测压技术进行的初步研究表明，在自主收缩过程中，PRM会增加肛管近端(头端)的压力，而EAS会增加肛管远端的压力。我们的初步研究还表明，阴道内的静息和挤压压力是由于PRM的收缩造成的。肛门括约肌功能障碍继发的大便失禁可能是由于肛门括约肌复合体的任何一个、两个或全部三个组成部分的缺陷所致，即IAS、EAS和PRM。我们认为PRM是大便失禁机制中的主要参与者，其功能障碍导致大便失禁。我们研究的具体目标是确定，1，肛管解剖(如三维超声图像)和测压测量的肛门括约肌功能之间的相关性，2，IAS，EAS和PRM对肛管压力的贡献：骨骼肌松弛对肛管压力的影响，3，阴道压力作为PRM功能的衡量标准，最后，PRM在大便失禁中的作用。我们确信，这项拨款中提出的新的研究方法将显著增强我们对肛门括约肌功能在健康和疾病中的了解，并使我们能够在未来开发更好的治疗大便失禁的治疗策略。

DESCRIPTION (provided by applicant): Fecal incontinence is a major health hazard and has significant impact on the quality of life. It has a prevalence of 2% to 7% in the community and affects up to 15% of adults in the United States older than 50 years of age. The pathophysiology of fecal incontinence is not well understood. The focus of our work is to better define the anal sphincter function. Specifically, we will investigate the role of puborectalis muscle (PRM) in the anal continence mechanism. The muscle fibers of the internal anal sphincter (IAS) and external anal sphincter (EAS) are arranged in a circular fashion. The PRM, on the other hand, is a "U" shaped muscle, the two ends of which are attached anterior to the pubic bone. It is not known if PRM muscle contributes to the anal canal pressures at rest or during squeeze. Our preliminary studies using 3D ultrasound and manometry show that during voluntary contraction, the PRM increases pressure in the proximal (cranial) part of the anal canal and the EAS increases pressure in the distal part of the anal canal. Our preliminary studies also show that resting and squeeze pressure in the vagina are due to contraction of the PRM. Fecal incontinence secondary to anal sphincter dysfunction may be due to defect in any one, two or all three components of the anal sphincter complex, i.e., IAS, EAS, and PRM. We propose that the PRM is a major player in the fecal continence mechanism and its dysfunction leads to fecal incontinence. The specific goals of our studies are to determine, 1; Correlation between anal canal anatomy (as seen on 3D ultrasound images) and anal sphincter function measured by manometry, 2; contribution of the IAS, EAS and PRM to the anal canal pressure: effect of skeletal muscle relaxation on the anal canal pressure, 3; vaginal pressure as a measure of PRM function and finally, 4; the role of the PRM in fecal incontinence. We are certain that the novel investigational approach proposed in this grant will significantly enhance our understanding of the anal sphincter function in health and disease, and allow us to develop better treatment strategy for treatment of fecal incontinence in the future.