DEFECOFLOWMETRY - A NEW TECHNIQUE FOR THE ASSESSMENT OF THE EVACUATION FUNCTION OF THE RECTUM

In a prospective study carried out on 78 patients with chronic constip ation (31, with slow transit, 47 with obstructive defecation disorders ) the evacuation function of the rectum during defecation was assessed by defecoflowmetry. These patients were compared to a control group o f normal volunteers (n = 32), The following parameters were evaluated: defecation and retention volume, defecation fraction, defecation time , maximum flow, mean flow rate and time to maximum flow, As expected, there was no difference in evacuation function between the group of pa tients with slow transit and the control group. Significant difference s, however. existed between the two types of constipation, as well as between obstructive defecation disease and controls, regarding all par ameters mentioned above. Evacuation function depends neither on octal neck pressure nor on intrarectal pressure. In patients with obstructiv e defecation disorders, three subgroups were discernable: one with pro longed time of defecation and satisfactory evacuation? one with prolon ged time of defecation and poor evacuation, and one small group of pat ients who were not able to defecate. Each group is based on a differen t underlying pathomechanism. We conclude that changes in evacuation fu nction of the rectum refer either to volume or to time of defecation, or to both. Changes are found only in obstructive type constipation, n ot in slow transit constipation. Therefore, defecoflowmetry as a dynam ic procedure can be used in screening for the classification of chroni c constipation.