Anal Sphincter Morphology & Function Assessed with Novel MR Imaging Techniques

肛门括约肌形态

• 批准号: 8235684
• 负责人: RAVINDER K. MITTAL
• 金额: $ 33.62万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-15 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8235684
• 关键词: Admission activity; Adult; Affect; Age; Anal canal; Anatomy; Anogenital region; Anterior; Anus; Birth; Cadaver; Child; Circular layer of muscularis propria of anal canal; Complex; Consensus; Data; Defect; Diffusion Magnetic Resonance Imaging; Episiotomy; External anal sphincter structure; Extravasation; Failure; Fecal Incontinence; Follow-Up Studies; Genetic Crossing Over; Human; Image; Imaging Techniques; Incontinence; Individual; Injection of therapeutic agent; Injury; Lateral; Lidocaine; Literature; Magnetic Resonance Imaging; Morphology; Motion; Motor; Movement; Muscle; Muscle Contraction; Muscle Fibers; Nature; Nursing Homes; Operative Surgical Procedures; Paper; Pathogenesis; Patients; Phase; Play; Polarization Microscopy; Population; Prevalence; Prevention; Procedures; Rectum; Rest; Role; Security; Sensory; Shapes; Side; Slice; Sphincter; Surgical incisions; Surgical sutures; Symptoms; System; Techniques; Thinking; Ultrasonography; United States; Vagina; Vaginal delivery procedure; Woman; Work; coccyx; improved; in vivo; injured; injury prevention; kinematics; men; novel; pressure; prevent; reconstruction; rectal; repaired; sphincter ani muscle structure; subcutaneous; success

DESCRIPTION (provided by applicant): Internal anal sphincter (IAS), external anal sphincter (EAS) and puborectalis muscle (PRM) are 3 sphincter mechanisms that provide triple security mechanism for the anal continence. EAS is most commonly affected muscle in patient with fecal incontinence, the reason being that it gets injured fairly frequently during vaginal child birth. Up to 35% of women have defects of the EAS muscle after the first vaginal delivery, as detected by US imaging. Overlapping sphincteroplasty is the most commonly performed surgery in patients with fecal incontinence when US images of the anal sphincter muscle show major anatomical defects. However, the success rate of the overlapping sphincteroplasty is less than 50% at 5 years. There are probably several reasons for the failure of overlapping sphincteroplasty; we propose that one of the reasons is incorrect understanding of the morphology of the EAS muscle. Current thinking is that the EAS is a ring or a donut shaped muscle and circumferential squeeze generated by the EAS muscle is responsible for the genesis of EAS contraction related increase in the anal canal pressure. Our preliminary data show that that the EAS is not a circular muscle; instead the muscle has the unique "figure of 8" type of morphology and the constricting action of the EAS is due to the "tying of knot" like action of what is currently known as the EAS and transverse perinea muscles. In fact, transverse perinea are actually extension of the EAS muscles. We use state of the art magnetic resonance imaging techniques, i.e., diffusion tensor imaging to determine the true morphology of EAS muscle. Furthermore, we use velocity encoded dynamic MR imaging to determine the dynamic motion of EAS muscle fibers to prove the nature of constricting action of EAS muscle. We believe that correct understanding of the EAS morphology is of paramount importance in prevention of injury in the first place and repair of EAS muscle during overlapping sphincteroplasty. Lateral episiotomy, which incises transverse perinea muscle, is thought to spare the EAS muscle, as compared to midline episiotomy in which the incision extends to the EAS muscle. We propose that the transverse perinea are indeed the EAS muscle and lateral episiotomy is not a sphincter sparing procedure. Our studies also show that the PRM is not only responsible for the formation of anorectal angle; it actually causes closure of the proximal half of the anal canal. For these studies, we utilize state of the art, 3D-US imaging and high definition manometery to prove our hypothesis. We are confident that our studies will provide a new understanding of the anatomy and function of anal canal and with this new understanding a significant stride can be made in the prevention and treatment of fecal incontinence. PUBLIC HEALTH RELEVANCE: Our studies show that the true morphology of the EAS muscle is different from our current understanding of a donut shaped muscle. Our studies use state of the art magnetic resonance imaging techniques to determine the true morphology and function of the EAS muscle. The proposed new EAS muscle morphology will, 1; prevent injury to the EAS muscle during vaginal delivery and 2; allow better surgical repair of the muscle to treat symptoms of fecal incontinence.

描述（由申请人提供）：肛门内括约肌（IAS）、肛门外括约肌（EAS）和耻骨直肠肌（PRM）是为肛门提供三重安全机制的3种括约肌机制。EAS是大便失禁患者最常见的受影响肌肉，原因是它在阴道分娩期间经常受伤。多达35%的妇女在第一次阴道分娩后有EAS肌肉缺陷，如US成像所检测到的。重叠括约肌成形术是大便失禁患者最常进行的手术，当肛门括约肌的超声图像显示主要的解剖缺陷。然而，重叠括约肌成形术的5年成功率低于50%。重叠括约肌成形术失败可能有几个原因，我们认为其中一个原因是对EAS肌形态的错误理解。目前认为EAS是一个环形或甜甜圈形肌肉，EAS肌肉产生的周向挤压是EAS收缩相关肛管压力增加的原因。我们的初步数据表明，EAS不是一个环形肌肉，而是肌肉具有独特的“8字”型形态和收缩行动的EAS是由于“打结”一样的行动，目前被称为EAS和横perforum肌肉。事实上，横韧带实际上是EAS肌肉的延伸。我们使用最先进的磁共振成像技术，即，扩散张量成像以确定EAS肌肉的真实形态。此外，我们使用速度编码动态磁共振成像来确定EAS肌纤维的动态运动，以证明EAS肌收缩作用的本质。我们相信，正确理解EAS形态是至关重要的，在预防损伤摆在首位，并修复EAS肌肉重叠括约肌成形术。与切口延伸至EAS肌的会阴中线切开术相比，切开会阴横肌的会阴外侧切开术被认为可以保留EAS肌。我们认为横会阴确实是EAS肌，会阴侧切术不是保留括约肌的手术。我们的研究还表明，PRM不仅负责肛门直肠角的形成，它实际上导致近端一半的肛管关闭。在这些研究中，我们利用最先进的3D-US成像和高清测压来证明我们的假设。我们相信，我们的研究将提供一个新的了解解剖和功能的肛管，并与这个新的理解，可以在预防和治疗大便失禁的重大进展。 公共卫生关系：我们的研究表明，EAS肌肉的真实形态与我们目前对甜甜圈形肌肉的理解不同。我们的研究使用最先进的磁共振成像技术来确定EAS肌肉的真实形态和功能。所提出的新EAS肌肉形态将：1;防止阴道分娩期间EAS肌肉损伤; 2;允许更好地手术修复肌肉以治疗大便失禁症状。