Electrically stimulated sartorius neosphincter: canine model of activation and skeletal muscle transformation.
The sartorius muscle was transposed into the abdominal cavity of six dogs, passed around a Thiry-Vella loop and sutured to itself to form a neosphincter. The muscle was activated by electrical stimulation and on contraction the neosphincter stopped or reduced the flow of saline through the Thiry-Vella loop in all animals until the onset of muscle fatigue. Continuous low frequency stimulation was used to transform the skeletal muscle, and when studied after a mean of 8 weeks of stimulation (range 6-11 weeks) the neosphincter stopped the flow for a significantly longer period of time (P = 0.027). Associated with the improved neosphincter function was a significant decrease in the fusion frequency (P = 0.003) and prolongation of the stimulus-peak tension time as assessed by a strain gauge sutured to the neosphincter muscle (P = 0.002). The changes in the contraction properties of the skeletal muscle suggest that continuous low frequency stimulation transformed the muscle fibres from type 2 to type 1, resulting in improved fatigue resistance and potential for continuous sphincter activity.
Hallan
R I
RI
Department of Neurology, London Hospital, Whitechapel, UK.
Williams
N S
NS
Hutton
M R
MR
Scott
M
M
Pilot
M A
MA
Swash
M
M
Koeze
T H
TH
Watkins
E S
ES
D000818:Animals; D004285:Dogs; D004558:Electric Stimulation; D005260:Female; D006614:Hindlimb / Q000502:physiology; D007082:Ileum / Q000601:surgery; D008297:Male; D008954:Models, Biological; D009119:Muscle Contraction / Q000502:physiology*; D009132:Muscles / Q000166:cytology / Q000502:physiology* / Q000637:transplantation