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3-D Endoanal Ultrasound: Normative Anatomy of the Anal Sphincter in Nulliparous Females

This study has been completed.
Information provided by (Responsible Party):
Karen Noblett, University of California, Irvine Identifier:
First received: May 6, 2010
Last updated: June 27, 2013
Last verified: June 2013
The purpose of this research study is to measure the muscles that make up your anal sphincter (muscles that control bowel movements) by using ultrasound. The most common way for women to injure these muscles is through childbirth. Some physicians think about 30% of women delivering their first baby develop some anal sphincter damage, which may or may not lead to symptoms such as anal urgency or incontinence (involuntary loss of gas or stool). The purpose of the study is to measure muscles in normal women who have never given birth or had an injury to their anal sphincter.

Condition Intervention
Normal (no Known Injury) Anal Sphincter Female Anatomy.
Procedure: 3-D Endoanal Ultrasound

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: Open Label
Official Title: 3-D Endoanal Ultrasound: Normative Anatomy of the Anal Sphincter in Nulliparous Females

Resource links provided by NLM:

Further study details as provided by Karen Noblett, University of California, Irvine:

Primary Outcome Measures:
  • To establish normative data for the anal sphincter complex in asymptomatic nulliparous females without sphincter disruption sphincter. [ Time Frame: 15 minute exam ]

Enrollment: 75
Study Start Date: December 2007
Study Completion Date: June 2012
Primary Completion Date: June 2012 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
nulliparous females
nulliparous women over the age of 18
Procedure: 3-D Endoanal Ultrasound
The subject will be placed in the supine position with their feet in the stirrups and a drape will be used, exposing only the anus and perineum in order to introduce the probe. In order to prevent and minimize any potential discomfort, the lubricated ultrasound probe will be gently inserted into the anal canal up to the anal verge, with minimal manipulation of the probe once inserted. The scan lasts approximately two minutes and the entire exam will take no more than five minutes.

Detailed Description:

Participants will be asked to complete a one page questionnaire. This questionnaire will address whether perineal trauma, sphincter lacerations, anal incontinence, and fecal urgency impact the subject on any level. Subjects will also be asked about their bowel habits and history of problems with bowel movements. Subjects will then be asked to undergo an ultrasound study of the anal sphincter at the time of enrollment. Completing the entire study will take no more than 15 minutes. This will be done at the doctor's office. Answering the questionnaire will take no more than 5 minutes.

The endoanal ultrasound is a probe with a diameter equivalent to the index finger. It is inserted in the rectum and measures the length and width of the sphincter muscles.


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • nulliparous women over the age of 18.

Exclusion Criteria:

  • any history of anal incontinence, chronic constipation, anorectal disease or trauma, neuromuscular or neuropsychiatric disease, diabetes, gastrointestinal disorders, or previous anorectal or pelvic surgeries.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01123109

United States, California
UCI Women's Healthcare
Orange, California, United States, 92868
Sponsors and Collaborators
University of California, Irvine
Principal Investigator: Karen Noblett, MD UCI Medical Center
  More Information

Responsible Party: Karen Noblett, Division Director, University of California, Irvine Identifier: NCT01123109     History of Changes
Other Study ID Numbers: 2007-5983
Study First Received: May 6, 2010
Last Updated: June 27, 2013

Keywords provided by Karen Noblett, University of California, Irvine:
nulliparous women processed this record on May 25, 2017