Prospective RCT of Obstructed Defecation Surgery: Comparing Transvaginal Rectopexy, Ventral Mesh Rectopexy and POP Repair (PROD Trial)

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Obstructed defecation (OD), defined as incomplete emptying of stool, is a widely prevalent disorder in women’s health and resulting in major quality of life (QOL) and healthcare burden. Successful management has been impaired, historically, by deficiencies relating to both diagnosis and treatment. First, there has been a persistent misconception that OD in the absence of dyssynergia (i.e., uncoordinated contraction of pelvic floor) results from prolapse of the posterior vaginal wall (‘rectocele’) and improves after its repair. In fact, prior studies have confirmed that this form of OD results from support defects involving the rectum rather than vagina (8-10), and moreover that rectocele repairs are unreliable in relieving OD symptoms. Recent work from our center confirmed rectal detachment and hypermobility to be the major determinants of OD in the irrespective of the presence of a rectocele. Secondly, traditional diagnostic modalities to asses rectal support as the source of OD are expensive (e.g. MRI defecography) and/or invasive (e.g. anal manometry), and often generate findings with unclear clinical correlation and impact on care. Finally, available surgeries to repair rectal support defects have been limited to invasive transabdominal or perineal methods, typically involving mesh implantation and reserved for severe cases, e.g. those with overt rectal prolapse. Laparoscopic or open ventral mesh rectopexy is the most widely accepted operation to stabilize rectal support. We are testing the hypothesis that OD symptoms in the absence of dyssynergia primarily result from deficiencies in rectal support and that patients presenting OD symptoms with or without vaginal prolapse undergoing our new diagnostic evaluation and surgical treatment will have improved outcomes relative to the current standard of care at 2 years after surgery. Our study is designed to evaluate primary and secondary outcomes relating to the two rectopexy procedures on OD at 2 years follow up across two institutions. This clinical data will be complemented by a computational modeling approach that aims to provide insight into the most likely contributors to OD symptoms, i.e. vaginal versus rectal support defects. Aim 1: Compare occult rectal hypermobility as measured using posterior compartment dynamic ultrasound imaging versus MR defecography. Posterior compartment dynamic ultrasound is a novel approach for identifying the underlying anatomic cause of OD in women suffering from OD symptoms without coexisting functional bowel disorders (e.g. normal BM frequency and stool type, and absence of dyssynergia). Aim 2: Compare anatomic, functional, and health-related quality of life outcomes in female subjects with moderate to severe OD symptoms, and rectal hypermobility diagnosed by ultrasound, who are randomized to minimally invasive transvaginal rectopexy versus abdominal ventral rectopexy at 2 years after surgery. Aim 3: Develop and validate a computational finite element model and statistical shape modeling approach to describe the mechanics of normal defecation and the role of rectal and vaginal support deficiencies in causing OD symptoms.