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1 FEMALE PELVIC FLOOR IMAGING: THE IMPACT OF PREGNANCY ON PELVIC ORGAN SUPPORT Caitlyn McCann, Steven Abramowitch PhD, Timothy Canavan MD, & Pamela Moalli MD, PhD University of Pittsburgh and Magee-Women’s Research Institute & Foundation INTRODUCTION Pelvic organ prolapse (POP) is the downward descent of the female pelvic organs, such as the bowel, bladder or uterus, into the vagina 1 . Pelvic organ descent progresses in a slow maner and ultimately results in varying degrees of physical discomfort. Women suffereing from POP often complain of urinary incontinence, difficult urination and defecation, low back pain, or feelings of pelvic pressure 2,3 . In addition, women suffering from POP may also experience emotional distress 4 . The physical and emotional toll associated with POP has a devastating impact on the quality of life of millions of women around the world. In the United States alone, over 10% of women undergo surgery to repair prolapse with the cost of prolapse surgery estimated around 1 billion dollars annually 5 . As the population continues to age, it is projected that the number of U.S. women suffering from POP will increase from 3.3 million in 2010 to 4.9 million in 2050, which is a 46% increase over the 40 year period 4 . While many factors, such as aging and increasing body-mass index, are believed to contribute to the cause of the disorder, the most significant risk factor associated with pelvic organ prolapse is pregnancy 1,6 . As a result, many women are choosing to undergo Ceserian deliveries as a means of preventing prolapse. Currently, there is no research data that supports this preventative strategy due to the fact that only a few studies have characterized pelvic organ support changes during pregnancy 7 . Recently, the use of ultrasound equipment has made it easier to investigate changes in the pelvic floor. In the past, diagnostic imaging was not used to view the pelvic floor due to poor quality imaging and the high cost of equipment. Today, the use of ultrasound to view the pelvic floor provides physicians and researchers with several advantages due to its ready availability, ease of use, and non-invasive nature 8 . OBJECTIVE Based on a lack of knowledge surrounding the main risk factor associated with prolapse, as well as the lack of studies involving the use of ultrasound to view the pelvic floor, the objective of the present study was determined. The present study aims to use ultrasound images to gain a better understanding of the anatomical differences of the pelvic floor at the different stages of pregnancy. SUCCESS CRITERIA In order to determine if the objective of the project has been statisfied, several criteria must be met. Minimal differences must result between intra- and inter-repeatabilily measurements. Additionally, measurements must be accurate. METHODS Midsaggetal and axial ultrasound images were acquired from a sample of 25 healthy females from Magee-Womens Hospital of UPMC. Inclusion creterion encompassed several factors such as 1) Pregnancy must be the woman’s first; 2) Must have the intention to deliver at the study site hospital; 3) Must be over the age of 18. The number of ultrasound images taken varied anywhere from 3 images to 9 images per participant. An imaging process software (OsiriX) was used to view the ultrasound images. Structures of interest were identified for both midsagittal (10 images) and axial (34 images) views. For the midsaggetal view, the pubic symphysis, levator ani, vagina, and certix were all identified. For the axial view, the urethra, vagina, rectum, and area of the levator hiatus were determined. After structures of interest were indentified, measurements were taken. For each image, all measurements were taken three times to assess for repeatabilty. For the midsagittal view, a coordinate axis was established. After identifying the pubic symphysis, a line was marked at the outer most portion of the ultrasound where the pubic symphysis border was located. The midpoint of the line was determined. The x-axis was established from this midpoint to the most anterior part of the levator ani. The y-axis was established at the posterior border of the pubic symphysis, perpendicular to the x-axis. Once the coordinate system was in place, three angles of interest could be determined. Angle 1 was a measurement of the angle the upper portion of vagina made with the x- axis. Angle 2 was a measurement of the angle the vagina made below the x-axis to an area where a second vaginal angle can be seen. Angle 3 was classified starting from the base of Angle 2, taking a measure of a second angle of the vagina, ending at the certvix (Figure 1).
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Page 1: Caitlyn McCann, Steven Abramowitch PhD, Timothy Canavan MD ... · Caitlyn McCann, Steven Abramowitch PhD, Timothy Canavan MD, & Pamela Moalli MD, PhD University of Pittsburgh and

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FEMALE PELVIC FLOOR IMAGING: THE IMPACT OF PREGNANCY ON PELVIC ORGAN SUPPORT Caitlyn McCann, Steven Abramowitch PhD, Timothy Canavan MD, & Pamela Moalli MD, PhD University of Pittsburgh and Magee-Women’s Research Institute & Foundation INTRODUCTION          Pelvic organ prolapse (POP) is the downward descent of the female pelvic organs, such as the bowel, bladder or uterus, into the vagina1. Pelvic organ descent progresses in a slow maner and ultimately results in varying degrees of physical discomfort. Women suffereing from POP often complain of urinary incontinence, difficult urination and defecation, low back pain, or feelings of pelvic pressure2,3. In addition, women suffering from POP may also experience emotional distress4. The physical and emotional toll associated with POP has a devastating impact on the quality of life of millions of women around the world. In the United States alone, over 10% of women undergo surgery to repair prolapse with the cost of prolapse surgery estimated around 1 billion dollars annually5. As the population continues to age, it is projected that the number of U.S. women suffering from POP will increase from 3.3 million in 2010 to 4.9 million in 2050, which is a 46% increase over the 40 year period4. While many factors, such as aging and increasing body-mass index, are believed to contribute to the cause of the disorder, the most significant risk factor associated with pelvic organ prolapse is pregnancy1,6. As a result, many women are choosing to undergo Ceserian deliveries as a means of preventing prolapse. Currently, there is no research data that supports this preventative strategy due to the fact that only a few studies have characterized pelvic organ support changes during pregnancy7. Recently, the use of ultrasound equipment has made it easier to investigate changes in the pelvic floor. In the past, diagnostic imaging was not used to view the pelvic floor due to poor quality imaging and the high cost of equipment. Today, the use of ultrasound to view the pelvic floor provides physicians and researchers with several advantages due to its ready availability, ease of use, and non-invasive nature8. OBJECTIVE Based on a lack of knowledge surrounding the main risk factor associated with prolapse, as well as the lack of studies involving the use of ultrasound to view the pelvic floor, the objective of the present study was determined. The present study aims to use ultrasound images to gain a better understanding of the anatomical

differences of the pelvic floor at the different stages of pregnancy. SUCCESS CRITERIA In order to determine if the objective of the project has been statisfied, several criteria must be met. Minimal differences must result between intra- and inter-repeatabilily measurements. Additionally, measurements must be accurate. METHODS Midsaggetal and axial ultrasound images were acquired from a sample of 25 healthy females from Magee-Womens Hospital of UPMC. Inclusion creterion encompassed several factors such as 1) Pregnancy must be the woman’s first; 2) Must have the intention to deliver at the study site hospital; 3) Must be over the age of 18. The number of ultrasound images taken varied anywhere from 3 images to 9 images per participant. An imaging process software (OsiriX) was used to view the ultrasound images. Structures of interest were identified for both midsagittal (10 images) and axial (34 images) views. For the midsaggetal view, the pubic symphysis, levator ani, vagina, and certix were all identified. For the axial view, the urethra, vagina, rectum, and area of the levator hiatus were determined. After structures of interest were indentified, measurements were taken. For each image, all measurements were taken three times to assess for repeatabilty. For the midsagittal view, a coordinate axis was established. After identifying the pubic symphysis, a line was marked at the outer most portion of the ultrasound where the pubic symphysis border was located. The midpoint of the line was determined. The x-axis was established from this midpoint to the most anterior part of the levator ani. The y-axis was established at the posterior border of the pubic symphysis, perpendicular to the x-axis. Once the coordinate system was in place, three angles of interest could be determined. Angle 1 was a measurement of the angle the upper portion of vagina made with the x-axis. Angle 2 was a measurement of the angle the vagina made below the x-axis to an area where a second vaginal angle can be seen. Angle 3 was classified starting from the base of Angle 2, taking a measure of a second angle of the vagina, ending at the certvix (Figure 1).

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Figure 1. Measurements in the midsagittal plane: Angle 1, 2, & 3. All angles were in reference to the center of the vaginal canal. For the axial view, the circumference of the levator hiatus was determined. The area was then calculated using UsiriX. Additionally the levator hiatus upper 1/3 diameter was measured (Figure 2).

Figure 2. Measurements in the axial plane: area of levator hiatus and levator hiatus upper 1/3 diameter. The data collected was statistically analyzed using Excel. ANOVAs were performed at a 95% confidence level for all parameters. Data was analyzed using the intra-class correlation coefficient (ICC). The Altman scale was used to determine reliability of values9. According to the scale, values under 0.20 were poor, 0.21-0.40 fair, 0.41-0.60 moderate, 0.61-0.80 good, and 0.81-1.00 very good. RESULTS The ICC values for intra-repeatability revealed that both measurements of interest on the axial viewed images were very good, while only Angle 1 received a very good reliability score based on the Altman scale. Angle 2 and 3 were deemed to have good reliabilty (Table 1). Table 1. Intra-repeatability of pelvic floor measurements ICC Reliability Midsagittal Angle 1 0.9600 Very Good Angle 2 0.7785 Good Angle 3 0.6426 Good Axial Area 0.9981 Very Good Upper 1/3 Diameter 0.9982 Very Good

Inter-repeatabilty was not determined at this time, as a second individual has yet to complete the measurements for all of the images. DISCUSSION The present study demonstrated good to very good reliabilty for all measurements of interest. Angle 1 showed very good reliablity, while Angle 2 and 3 revealed good reliablity for the midsagittal images. This is most likely a result of incomplete imaging of the cervix when using ultrasound. All measurements determined for the axial view were classified as being very good. All measurements taken were determine to be accurate based on improved image quality. This study was limited by several factors. The use of ultrasound still has its flaws, as not being able to capture the cervix effects measurements for Angle 2 and 3. Also, the sample size was rather small, especially for the midsagittal images. A larger sample would broaden the range of data and help to form a more conhesive picture for analysis. Looking to the future, inter-repeatibility will be determined. Once all measurements are deemed repeatable, the methods used for taking measurements can be utilized to compare the anatomical differences of the pelvic floor at the different stages of pregnancy. CONCLUSION Pelvic organ prolapse is a condition that effects the lives of millions of women around the globe. If proven reliable, measurements taken using ultrasound images could prove to be an effective means of learning more about the anatomy of the pelvic floor. Insight into the changes that occur to the pelvic floor during the different stages of pregnancy will allow physicians and researchers to gain a better understanding into the leading cause of pelvic organ prolapse. ACKNOWLEDGEMENTS A big thank you to Dr. Steven Abramowitch. REFERENCES 1 Jelovsek, J. Eric, Christopher Maher, and Matthew D. Barber."Pelvic Organ Prolapse." The Lancet 369.9566 (2007): 1027-1038.  2 Johns Hopkins University Faculty. "Pelvic Organ Prolapse." Johns Hopkins Medicine. Department of Gynecology & Obstetrics, 2013. Web. 28 Nov. 2013.  3 Swift, Steven E., Susan B. Tate, and Joyce Nicholas. "Correlation of Symptoms with Degree of Pelvic Organ Support in a General Population of Women: What Is Pelvic Organ Prolapse?" American Journal of Obstetrics and Gynecology 189.2 (2003): 372-377.  4 Wu, Jennifer M., Andrew F. Hundley, Rebekah G. Fulton, and Evan R. Myers. "Forecasting the Prevalence of Pelvic Floor Disorders in U.S. Women: 2010 to 2050." Obstetrics & Gynecology 114.6 (2009): 1278-1283.  5 Weber, Anne M., MD, and Holly E. Richter, MD. "Pelvic Organ Prolapse." Obstetrics & Gynecology 3.106 (2005): 615-634.  6 Shagam, Janet Y. "Pelvic Organ Prolapse." Radiologic Technology 77.5 (2006): 389.  7 Yeniel, A. O., A.M. Ergenoglu, Niyzai Asker, Isma II M. Itil, and Reci Meseri. “How Do Delivery Mode and Parity Affect Pelvic Organ Prolapse?” Acta Obstetricia Et Gynecologica Scandinavica 92.7 (2013): 847-851.  8 Dietz, H. P. "Ultrasound Imaging of the Pelvic Floor.Part I: Two-dimensional Aspects." Ultrasound in Obstetrics and Gynocology 23 (2004): 80-92.  9 Altman, Douglas G. Practical Statistics for Medical Research. London: Chapman and Hall, 1991.


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