Electrical control of intestinal reservoirs in a chronic dog model

Pouches constructed from small intestine are used to replace reservoir function after extirpative surgery of the colon. Such pouches empty in an involuntary and uncontrolled fashion. To see whether emptying could be voluntarily controlled, ileal and jejunal reservoirs were constructed in eight dogs under general anesthesia. Four pairs of stainless steel electrodes were attached to the serosa at 5 cm intervals, and the pouches were intubated for pressure measurements with 1.67 mm polyethylene catheters. All lines were brought subcutaneously to the neck where they were maintained under a protective jacket. One to four weeks later, the pouches were stimulated with trains of square wave pulses at frequencies between 3 Hz and 1.67 KHz. The pouches were injected with contrast, and the results were monitored by fluoroscopy. Intrapouch pressure increases as high as 80 mmHg were seen after stimulation at 3 Hz, 100 msec and 6 Hz, 50 msec (10 to 25 mA) and emptying was induced. Pressure increases were also seen after stimulation with 330 Hz, 1 msec and 10 Hz, 1 msec pulse trains, but emptying was not documented. Abdominal wall contraction during stimulation was a problem but could be inhibited by interposing an insulating silastic sheet. The conclusion was made that it is possible to electrically induce emptying of intestinal reservoirs in a chronic dog model.