Pathophysiology, diagnosis and biofeedback therapy in fecal incontinence using fecobionics

ABSTRACT Fecal incontinence (FI) affects 1 in 7 Americans with a rising incidence that poses a major healthcare burden. Its pathophysiology is poorly understood and consequently there is dearth of effective treatment(s). A critical barrier to progress has been the lack of comprehensive, physiologically-relevant and practical diagnostic test for identifying the underlying mechanism(s). Current tests provide either incomplete or conflicting information that do not correlate with symptoms and treatment outcomes. Our goal is to determine the role of anorectal muscles in maintaining continence and facilitating defecation, and how anorectal malfunctions can cause FI by using a novel technology called Fecobionics (an electronic simulated stool) to evaluate its diagnostic and therapeutic utility. Fecobionics has the consistency and shape of normal stool that can record pressures, cross- sectional area, orientation, and viscoelastic properties of the anorectum. With heavily upgraded hardware, software and graphical user interface, the new Fecobionics device map the geometric profiles during evacuation and relate them to simultaneous changes in pressures (forces) and bending. Our central hypothesis is that the movement of the Fecobionics device through the anorectum will provide unknown and new mechanistic insights on anorectal physiology including intraluminal pressure changes, anal muscle length-tension relations, resistance generated during movement of the surrogate stool and its deformability, as well as distensibility of the anal sphincters in normal subjects and FI patients. This multidimensional data could facilitate new treatments for FI. Accordingly, our Specific Aims are to: 1) Determine the length-tension properties of the anal sphincters using Fecobionics in normal subjects and FI patients during anal distension and during simulated evacuation. 2) Elucidate the pathophysiological characteristics and biomechanical properties of individual muscle components, external, internal anal sphincter and puborectalis muscle using the Fecobionics device and comparing FI patients with normal subject controls; and 3) Evaluate the use of Fecobionics as a biofeedback treatment (BT) and monitoring tool in FI patients to determine the predictors for treatment success, by performing a randomized controlled trial of Fecobionics-assisted Biofeedback Therapy (FBT) versus conventional Office-based Biofeedback Therapy (OBT). Our proposal seeks to shift current FI research by testing a stool surrogate for performing BT as opposed to a thin manometry probe and examine the multi-dimensional physiologic changes (i.e., pressure, deformability, biomechanics, vectoral and topographic changes) as well as clinical outcome following BT. The unique aspect of our proposal is to simulate stooling with a wireless bionics device and examine in detail the mechanistic underpinnings in health and in FI patients. The impact of our project is to provide new mechanistic understanding of anorectal function and pathophysiology in FI and validate the clinical utility of a novel, highly integrated device for diagnostics and facilitation of biofeedback therapy with an unprecedented graphical feedback to the patient of mechanosensory actions.