title: A technique for sequential segmental neuromuscular stimulation with closed loop feedback control.
abstract: In dynamic myoplasty, dysfunctional muscle is assisted or replaced with skeletal muscle from a donor site. Electrical stimulation is commonly used to train and animate the skeletal muscle to perform its new task. Due to simultaneous tetanic contractions of the entire myoplasty, muscles are deprived of perfusion and fatigue rapidly, causing long-term problems such as excessive scarring and muscle ischemia. Sequential stimulation contracts part of the muscle while other parts rest, thus significantly improving blood perfusion. However, the muscle still fatigues. In this article, we report a test of the feasibility of using closed-loop control to economize the contractions of the sequentially stimulated myoplasty. A simple stimulation algorithm was developed and tested on a sequentially stimulated neo-sphincter designed from a canine gracilis muscle. Pressure generated in the lumen of the myoplasty neo-sphincter was used as feedback to regulate the stimulation signal via three control parameters, thereby optimizing the performance of the myoplasty. Additionally, we investigated and compared the efficiency of amplitude and frequency modulation techniques. Closed-loop feedback enabled us to maintain target pressures within 10% deviation using amplitude modulation and optimized control parameters (correction frequency = 4 Hz, correction threshold = 4%, and transition time = 0.3 s). The large-scale stimulation/feedback setup was unfit for chronic experimentation, but can be used as a blueprint for a small-scale version to unveil the theoretical benefits of closed-loop control in chronic experimentation.
authors.affiliation: Division of Plastic and Reconstructive Surgery, Department of Surgery, School of Medicine, University of Louisville, Kentucky, USA. zon@bart.nl
authors.forename: Erik D H
authors.initials: ED
authors.lastname: Zonnevijlle
authors.forename: Gustavo Perez
authors.initials: GP
authors.lastname: Abadia
authors.forename: Naveen N
authors.initials: NN
authors.lastname: Somia
authors.forename: Moshe
authors.initials: M
authors.lastname: Kon
authors.forename: John H
authors.initials: JH
authors.lastname: Barker
authors.forename: Steven
authors.initials: S
authors.lastname: Koenig
authors.forename: D L
authors.initials: DL
authors.lastname: Ewert
authors.forename: Richard W
authors.initials: RW
authors.lastname: Stremel
mesh_terms: D000465:Algorithms; D000818:Animals; D004285:Dogs; D004599:Electric Stimulation Therapy; D005246:Feedback / Q000502:physiology; D009119:Muscle Contraction; D018763:Muscle Fatigue; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology* / Q000637:transplantation*; D011312:Pressure; D014521:Urethra; D014549:Urinary Incontinence / Q000601:surgery