Background: Methods are needed for propulsion of endoscopes and wireless vi
deo capsules along the small intestine. This work aims to test the hypothes
is that electrical stimulation could propel an endoscope by stimulating mus
cular contraction.
Methods: Prototype acrylic ovoid-shaped devices were constructed with 2 sta
inless steel electrodes mounted on the tapered section, Five devices 15 to
23 mm diameter with a taper of 28 degrees to 40 degrees (included angle) we
re tested. When these devices were in contact with the bowel wall, electros
timulation was applied causing circular muscle contraction, which when appl
ied to the taper of the ovoid resulted in forward propulsion of the device.
The method does not induce peristalsis but works by stimulating local cont
raction. The device was tested in the small intestine and esophagus of anes
thetized pigs,
Results: Electrostimulation caused the ovoid to advance rapidly (6 mm/sec)
up and down the esophagus by inducing circular esophageal muscle contractio
n. When stimulated at 15 Hz with 30-ms pulses, the threshold for movement i
n the small intestine was 12 mA; at 20 mA the device moved reliably in eith
er direction in the small intestine at speeds of up to 4.5 mm/sec and negot
iated tight curves,
Conclusion: Electrostimulation can move endoscopes in the small intestine.