EFFECT OF MAGNETIC STIMULATION ON THE CONTRACTILE ACTIVITY OF THE RECTUM IN THE DOG

Purpose: Magnetic stimulation (MS) produces its effect, according to F araday's law, by creating an electric field which can stimulate the ne uromuscular tissues. The current study investigates, to our knowledge for the first time, the effect of MS on rectal pressure and evacuation with a view on its possible application in emptying the inertic or ne uropathic rectum. Methods: The rectal, rectal neck and vesical pressur es as well as the EMG activity of the two rectus abdominis muscles wer e recorded during sacral MS with a magnetic coil while the rectum was empty and while filled. Stimulation parameters were set at 70% intensi ty, 20 Hz freqency and 1- to 5-second burst length. Results: Sacral MS of both the filled and empty rectum effected a significant increase i n rectal (p < 0.01) and vesical (p < 0.01) pressures and a decrease in rectal neck pressure (p < 0.01). Rectal evacuation of the filled rect um using intermittent stimulation was achieved in all animals. Conclus ion: Sacral MS resulted in a rectal evacuation. It is a simple, easy a nd noninvasive method that might prove applicable in the treatment of inertic constipation and neuropathic rectum.