Abstract Interstitial cystitis/ bladder pain syndrome (IC/BPS) is one of the most debilitating chronic pelvic pain (CPP) conditions that negatively impacts the quality of life and sexual activities in 2.7% to 6.5% of women in the US. Pelvic floor hypertonicity (PFH) is prevalent among patients with CPP, and is present in up to 85% of women with IC/BPS. PFH is a multifactorial problem that involves impaired relaxation of the pelvic musculature due to the activation of nociceptors and release of inflammatory chemicals. Current clinical strategies employ physical therapy interventions to relax the muscle to improve muscle coordination. Alternative therapies that use oral or intra-vaginal muscle relaxants may be suggested when conservative methods fail. Specifically, botulinum neurotoxin (BoNT), has received growing interest in managing pelvic pain secondary to PFH. BoNT inhibits the neuromuscular transmission at neuromuscular junctions, indicated by innervation zones (IZs), by blocking the acetylcholine release, leading to transient muscle relaxation, and the relief of pain symptoms. Despite its potency and safety, BoNT can cause dose-dependent adverse effects and is expensive. Studies have demonstrated that increasing the injection distance by 1 cm from the IZs reduced the effect of BoNT by 46%. It is clinically important to localize in vivo the IZ distributions in the pelvic floor muscles to guide precision BoNT injections for optimal treatment efficacy with reduced treatment cost. Our team has successfully developed a novel high-density surface electromyography (HD-sEMG) technique to 1) reliably and quantitatively assess PFH and 2) accurately image the IZ distributions of hypertonic PFMs, and has 3) successfully demonstrated the significant improvement in treatment outcome of BoNT injection with HD-sEMG vs. without HD-sEMG guidance, in managing muscle spasticity. The goal of this proposal is to develop a personalized, precision BoNT injection approach guided by intra-vaginal HD-sEMG to optimize the treatment outcome in IC/BPS management. This research represents the first effort to quantitatively and objectively study the feasibility of using intra-vaginal HD-sEMG for personalized, precision guided BoNT injections to optimize the diagnosis and treatment of IC/BPS. The proposed technique will serve as an in vivo pelvic floor phenotyping tool that can be used to deliver personalized injection of BoNT to personalized injection sites with personalized doses, which will lead to more effective BoNT treatment with reduced treatment cost (by reducing injection dose). The study will also advance our understanding of the pathophysiology of PFH, and mechanism of BoNT management, and help establishing an advanced standard of objective assessment of PFH and BoNT injections.

Project Narrative Interstitial cystitis/ bladder pain syndrome (IC/BPS) is one of the most debilitating chronic pelvic pain (CPP) conditions that negatively impacts the quality of life and sexual activities in 2.7% to 6.5% of women in the US. Botulinum neurotoxin (BoNT) has received growing interest in managing IC/BPS, but it can cause dose- dependent adverse effects and is expensive. This research represents the first effort develop a personalized, precision BoNT injection approach guided by intra-vaginal high-density surface EMG to optimize the treatment outcome in IC/BPS management.