AGA Abstracts Sa1356 Micro CT and Histology Evidence for the "Purse String" Morphology of the External Anal Sphincter Melissa M. Ledgerwood, Esther Cory, Robert L. Sah, Ahmed Shabaik, Shantanu Sinha, Ravinder K. Mittal Background: Our recent study that utilized 3D ultrasound and magnetic resonance imaging "suggests" that the external anal sphincter (EAS) morphology is like a "purse string" rather than a circle (as has been assumed for > 300 years). The "purse string" morphology consists of right and left transverse perinea muscles crossing in the midline structure of the perineal body (PB) to continue as right and left EAS muscles on the lateral sides. Goal: We further investigated the EAS anatomy, especially myo-architecture in the PB, using contrast enhanced micro CT scanning that enables elucidation of the muscle structure to the level of muscle fascicles as well as microscopic histology. Methods: Studies were conducted on the 2 formalin-fixed human cadavers, a male (57yo) and a nulliparous female (32yo). MR imaging of the pelvis was conducted and a (35mm) 3 section that contained the ventral half of the anal canal along with the PB was isolated. The sample was stained with 3% phosphotungstic acid (PTA), and then μCT scanned periodically until PTA staining was complete with a Skyscan 1076 (Kontich, Belgium) at (9 μm) 3 voxel size. The reconstructed image data were viewed with Skyscan Dataviewer and CTVox software to create 2D images, movies and a 3D volume render. For histology the specimen was sectioned at 2mm intervals along the whole length of the anal canal and stained with H&E. Results: Histology of the female specimen at two locations in the middle of the EAS (PB) region are shown in Fig1.A,B. On the lateral aspects, the EAS consists of 2 muscle bundles, the inner (medial) that are oriented in the dorso-ventral direction and outer (lateral) oriented in the cranio-caudal direction. In the ventral midline region, (12 O clock position, region of PB), the fiber orientation is consistent with crisscross arrangement. The μCT scans showed regions of relatively high attenuation (bright) consistent with muscle staining by PTA, and relatively low attenuation (dark) consistent with minimally-stained fat/connective tissues between muscles (Fig. 2). The 3D volume render shows EAS muscle fascicles crossing in the PB. The 3-D movie and periodically-spaced 2-D sections (Fig. 2A-D) demonstrate the muscle fascicles traversing obliquely forming a unique "weaving pattern". Conclusion: These studies confirm that the muscle fibers from the two sides cross in the midline structure of PB to form the "purse string" morphology of the EAS. Further studies are needed to define the lateral and posterior aspects of the EAS and attachment to the bones to fully understand the complex morphology of the EAS. Sa1357 External Anal Sphincter Dysfunction in Patients With Anal Incontinence - Length-Tension Studies Reveal Presence of Reserve Function in Majority of Patient Melissa M. Ledgerwood, Anita Dev, Ravinder K. Mittal Background: Our studies shows that the external anal sphincter (EAS) and puborectalis muscle (PRM) operate at a short sarcomere length, i.e, under physiological conditions the force generated with voluntary squeeze by these muscles is significantly smaller compare to the force they can generate at their optimal lengths. Increasing the length of EAS and PRM (by increasing the diameter of anal and vaginal probes) increases the voluntary squeeze pressures in normal subjects (length tension function). We propose that the gain in function with the increase in muscle length is a muscle reserve that may be tapped to improve the continence function. Goals: To determine if patients with anal incontinence have different length-tension properties compared to control subjects. Methods: We studied 44 age and S-302 AGA Abstracts parity matched asymptomatic controls and 43 patients with anal incontinence to compare the length-tension function of the EAS and PRM. Anal canal pressure was studies using probes of diameters, 5, 10, 15 and 20mm, and vaginal pressure using probes of diameter 10, 20 and 30mm. Data Analysis: The difference between the rest and maximal squeeze pressure of the anal and vaginal canal was the voluntary EAS and PRM function. Results: All controls demonstrated an increase in the EAS and PRM pressure with the increase in the probe size (Figure 1). In 6 patients with anal incontinence there was no increase in the anal and vaginal pressure with voluntary squeeze with any of the probes. These patients were judged to have no EAS and PRM function. On the other hand, in majority (37/43) of patients, the anal and vaginal pressures increased with the increase in the probe size, albeit the amplitude of pressure increase was significantly smaller in patients compared to controls. Low squeeze pressures measured with the 5mm and 10mm probes was a good predictor of the abnormal length tension function of the EAS and PRM (Figure 2). Conclusions: 1) Majority of patients with anal incontinence have abnormal length-tension function of the EAS and PRM suggesting that these muscle must play important role in the pathogenesis of anal incontinence. 2) Increase in pressure with the increase in probe size in patients indicates the presence of EAS and PRM reserve function. We propose that adjusting the length of the PRM and EAS muscles to increase in the anal and vaginal squeeze pressure may be a viable strategy to treat anal incontinence. Figure 1: Pressure increase with probe size. A) Anal pressures B) Vaginal Pressures. Figure 2: ROC curves of A) Anal Probes and B) Vaginal Probes. Sa1358 Men Report More Severe Fecal Incontinence Symptoms Than Women: Patients' Perspective Sarina Pasricha, Steve Heymen, Olafur S. Palsson, William E. Whitehead Introduction Little is known about gender differences in the natural disease course of fecal incontinence (FI). Aims and Methods: The aim of this study was to describe gender differences in FI symptomology using a national survey in order to understand the disease course from the patients' perspective. We used a nationwide U.S. Internet survey that included adults with FI. FI was defined as accidental loss of liquid or solid stool at least once in the past 30 days. Subjects were nationally stratified based on age, gender and ethnicity. Demographic information was collected on all subjects. Subjects completed FI severity instruments includ- ing the Fecal Incontinence Severity Index (FISI), the Fecal Incontinence and Constipation Assessment (FICA) scale, the Perceived Stigma Scale (FI-PSS), and the Fecal Incontinence Quality of Life (FIQOL) scale. Bivariate analysis was done to compare differences between genders in the duration and characteristics of FI, and methods of coping. Results: 234 surveys were completed, but 48 (20.5%) were excluded from the analysis due to inconsistent answers on 2 quality control questions; 186 surveys (97 women; 89 men) were included for analysis. Men reported experiencing FI at a younger age (39.6 vs. 46.1 years, p=.01), and had higher FISI and FICA scores (Table 1) compared to women. Men experienced more frequent FI symptoms, and increased frequency and volume of stool leakage volume since FI onset. Men more frequently described daily leakage of liquid stool (43% vs. 16%, p = 0.001), mucus stool (37% vs. 13%, p = 0.0103) and gas leakage (37% vs. 13%, p = 0.002). Perceived stigma was greater for men than for women (75.1 vs. 54.2, p=.001); however, FIQOL total scores (2.5 vs. 2.7, p=.08) and consultation rates were similar in men and women. Coping differences: Men were more likely to use laxative or antidiarrheal medications to help with FI, and they perceive treatment as more effective (66.5% vs. 55.5%, p=0.007). Males were more likely to avoid visiting friends (p=0.037) or staying overnight away from home (p = 0.026). Both men and women decreased the amount of food they ate before going out (99% vs. 94%; p = 0.226), but men were more likely to completely avoid eating out (56.0% vs. 35.2%; p = 0.036). Roughly 75% of both men and women specifically locate the bathrooms in a new location. Men were more likely to be concerned about and afraid to have sex (59.5% vs. 40.5%, p=0.037). Conclusion: Interestingly, in this self-reported, national survey, men had more severe FI symptoms than women as evidenced by higher FICA and FISI scores. More research is needed to understand differences in etiology and