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。它在社区的患病率为2%至7%，在美国50岁以上的成年人中，发病率高达15%。大便失禁的病理生理机制尚不清楚。我们的工作重点是更好地界定肛门括约肌的功能。具体来说，我们将探讨耻骨直肠肌（PRM）在肛门失禁机制中的作用。内肛门括约肌（IAS）和外肛门括约肌（EAS）的肌纤维呈圆形排列。另一方面，PRM是一个“U”形肌肉，其两端附着在耻骨前方。目前尚不清楚PRM肌是否在休息或挤压时对肛管压力有贡献。我们使用3D超声和测压的初步研究表明，在自愿收缩期间，PRM增加肛管近端（颅）部分的压力，EAS增加肛管远端部分的压力。我们的初步研究还表明，静息和挤压压力在阴道是由于收缩的PRM。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种、两种或全部三种成分（即IAS、EAS和PRM）的缺陷所致。我们认为PRM在大便失禁机制中起主要作用，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（3D超声图像）与测压法测量的肛门括约肌功能的相关性，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功能的测量，最后，4；PRM在大便失禁中的作用。我们确信，这项资助提出的新研究方法将大大提高我们对肛门括约肌在健康和疾病中的功能的理解，并使我们能够在未来制定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.