Three-dimensional static parametric modelling of phasic colonic contractions for the purpose of microprocessor-controlled functional stimulation

Abstract

The study aimed at creating an integrated electromechanical model of invoked phasic contractions in canine colon during direct high frequency voltage stimulation. The model utilized data obtained from two large anaesthetized dogs that underwent laparotomy and serosal implantation of two circumferential electrode pairs into a distal segment of the left colon. The strength distribution of the stimulating electric field was analysed over a cylindrical mesh-surface grid modelling the interrogated colonic segment. Recordings of the stimulating current were utilized to model smooth muscle depolarization using linearized macroscopic tissue conductivity. The invoked contractile stress was related to the stimulating electric field strength using an exponential sigmoid function. Artificially produced occlusion of the lumen was derived for a pair of 5mm electrodes positioned on a cylindrical mesh-surface of 2 cm diameter and 15 cm length. The model simulated contractions invoked by stimuli of different amplitude (up to 12 V) with 98.6% accuracy of approximation. Macroscopic tissue conductivity was modelled as a combination of two first-order exponential terms involving a 3ms time constant. Real-time simulation of the current drawn by the smooth muscle during 10 V/50Hz bipolar voltage stimulation was performed. The integrated electromechanical model facilitates the quantification of microprocessor-controlled phasic colonic contractions.

Microprocessor controlled movement of solid colonic content using sequential neural electrical stimulation

“…Six healthy dogs (four males, two females; weight 28.6 (7.8) kg; length 114 (19) cm; body mass index 22.12 (3.39) kg/m 2 ) underwent laparotomy under Pentothal anaesthesia (Abbott, Montreal, Quebec, Canada). The initial dosage of anaesthesia was 30 mg/kg, supplemented with 3 mg/kg as needed based on the corneal reflex.…”

Implantable neural electrical stimulator for external control of gastrointestinal motility

“…It was also noted that many of these diseases do not respond to standard pharmacological and dietary treatments. Neural electrical stimulation has been actively pursued as an alternative means of restoring the impaired functionality of the stomach for the purpose of treating gastroparesis [27][28][29][30] and of the colon for the purpose of treating chronic constipation [31][32][33]. In addition,…”

Microprocessor-controlled movement of solid colonic content using sequential neural electrical stimulation

“…We have described such computer models for the stomach 18 and colon. 19 The purpose of this study was to determine if movement of solid colonic content could be achieved using microprocessor controlled sequential electrical stimulation in the colon.…”