Transcutaneous electrosigmoidography. Study of the myoelectric activity of sigmoid colon by surface electrodes.

The purpose of this study was to determine the feasibilty of performing transcutaneous electrosigmoidography (TC-ESG). The study involved 19 healthy volunteers (11 men, 8 women; mean age 38.2 +/- 14.8 years). To validate the results of TC-ESG, the latter was performed simultaneously with intra-sigmoid ESG. TC-ESG was done also in five patients who underwent sigmoidectomy. The optimal position of the electrodes was determined after several trials. Two electrodes (Beckman) were applied, each 2-3 cm away from the middle of a line drawn from the umbilicus to the symphysis pubis. A third electrode was placed just above the symphysis pubis. A reference electrode was applied to one of the lower limbs. For intra-sigmoid IS-ESG, two silver-silver chloride electrodes were introduced from the anal orifice into the sigmoid colon and were attached to the mucosa by suction. Pacesetter potentials (PPs) were recorded as regular negative deflections. They had constant amplitude, frequency and velocity when recordings were obtained in the same subject. The PPs registered transcutaneously had the same amplitude, frequency and velocity as those recorded intrasigmoidally. Action potentials could be registered only intrasigmoidally and not transcutaneously. No electric waves could be recorded by TC-ESG in 5 patients who had undergone sigmoidectomy. In conclusion, TC-ESG is a simple, non-invasive and non-radiologic technique that can substitute intra-sigmoid ESG and potentially can be used in the diagnosis of various pathologic conditions of sigmoid colon.