[Motility of the colon: electric and manometric description of the mass movement].

"Mass movement" was described at the beginning of the century by radiologists, who occasionally observed during exploration a sudden transport of barium from one section of the colon to another. In this paper we focused our attention on the electromechanical factors that accompany evacuation through a colostomy, since we thought that these would be the myoelectrical and pressure translation of the "mass phenomenon" described by radiologists. We used an electromyographic recording probe to which a conventional microtransducer probe was affixed by suction. Using this method we made 24-hour recordings in 8 patients with sigmoid colostomy. We observed five large evacuations. When the electrical and pressure phenomena that occurred a few minutes before evacuation were analyzed, two clearly differentiated phases were apparent. The first, which we called the "previous phenomenon", consisted of a succession of contractions and spike potentials over a mean period of 5.6 min. (sigma = 2.22), after which a "large contraction" appeared, with a mean pressure value of 127 mmHg (sigma = 38.77) and a mean electrical value of 10.6 mv. The mean duration of this phenomenon was 24.93 sec (sigma = 6.19) and it was recorded almost synchronically in the three recording points studied. Undoubtedly, these electrical-pressure phenomena resulted from mass transport since in all 5 cases a large discharge through the colostomy was seen.