Biomechanics and Electromyography Inassessing Female Stress Urinary Incontinence



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Introduction: Stress urinary incontinence (SUI), the involuntary urinary leakage associated with increases in intra-abdominal pressure, has a prevalence of 25–50% in U.S. women and the number of those who will undergo surgery will increase by half in the next forty years. SUI negatively affects the patient’s quality of life and places a great burden to the society. The functional anatomy of the continence mechanism remains vaguely understood. Hence my dissertation aims at offering a complete description of the pelvic floor muscles (PFM), the key contributor to the continence, thorough biomechanical and neurophysiological approaches. Methods: The biomechanical approach involves the development of a subject-specific finite element (FE) model of the female pelvic floor region. Subsequent computer simulations are targeted at finding the most contributive muscle to the urethral support function and evaluating current treatment strategies using a mini-sling. The neurophysiological approach involves the implementation of a novel surface electromyography (EMG) probe to acquire bioelectrical information of PFMs and the assessment of their innervations in healthy subjects and patients. Results: An FE pelvic floor model was developed which incorporates 40+ anatomical structural in the pelvis, representing the most complete model in the field. Simulation results showed that the vaginal walls, puborectalis, and pubococcygeus are the most important structures and that mid-distal post-urethral implantation represents the optimal location. Innervation zones of PFMs have been successfully identified and described for multiple PFMs. An high-density surface EMG-based motor unit number estimation approach was developed, providing a novel tool to evaluate the condition of neurologically impaired PFM. Conclusions: The combined information greatly advances our understanding of the physiology of PFM and would lay a firm foundation to novel, non-invasive, patient-specific interventional strategies in the future.



Biomechanics, Electromyography, Pelvic floor muscles, Pelvic floor disorder, Stress urinary incontinence


Portions of this document appear in: Peng, Yun, Rose Khavari, Nissrine A. Nakib, Timothy B. Boone, and Yingchun Zhang. "Assessment of urethral support using MRI-derived computational modeling of the female pelvis." International urogynecology journal 27, no. 2 (2016): 205-212. Peng, Yun, Rose Khavari, Nissrine A. Nakib, Julie N. Stewart, Timothy B. Boone, and Yingchun Zhang. "The single-incision sling to treat female stress urinary incontinence: a dynamic computational study of outcomes and risk factors." Journal of biomechanical engineering 137, no. 9 (2015): 091007. And in: Dias, Nicholas, Yun Peng, Rose Khavari, Nissrine A. Nakib, Robert M. Sweet, Gerald W. Timm, Arthur G. Erdman, Timothy B. Boone, and Yingchun Zhang. "Pelvic floor dynamics during high-impact athletic activities: a computational modeling study." Clinical Biomechanics 41 (2017): 20-27. And in: Peng, Yun, Jinbao He, Rose Khavari, Timothy B. Boone, and Yingchun Zhang. "Functional mapping of the pelvic floor and sphincter muscles from high-density surface EMG recordings." International urogynecology journal 27, no. 11 (2016): 1689-1696. And in: Peng, Yun, Jinbao He, Bo Yao, Sheng Li, Ping Zhou, and Yingchun Zhang. "Motor unit number estimation based on high-density surface electromyography decomposition." Clinical Neurophysiology 127, no. 9 (2016): 3059-3065.