Introduction This study aims to analyse rectal and anal pressure changes in relation to different rectal volumes and relation to patients’ symptoms with 3d plotting, illustrating the dynamic interaction between the rectum and anal canal.
Method The study involved 10 controls, 10 incontinent patients and 10 patients with constipation. Anorectal manometry was done using 8 channels spirally arranged with increasing rectal volume of 10 ml/10 sec, with 3d plotting of rectal volume versus different anorectal pressures.
Results In the control group, reproducible non-linear characteristic rectal plotgram is produced, in which changes in the curves divided into phases are correlated with patient symptoms and illustrating changes in rectal compliance. In patients with constipation, low rectal pressures were associated with less changes in anal sphincter relaxation illustrating how rectal inertia may contribute to difficult evacuation. Patients with pelvic dyssynerigia were associated with normal rectal curves but with abnormal anal relaxation. In patients with anal incontinence, different categories of patients are classified according to the curves. Abnormal rectal curves are associated with abnormal reflex relaxation of the anal sphincters. In patients with severe sphincteric injury, abnormally low rectal pressures are produced. In patients with rectal prolapse, higher rectal pressures are found. In patients with normal resting and squeeze pressures, abnormally low rectal compliance curves are produced with marked changes in anal pressures.
Conclusion Manometry is not a simple measure of anal pressures. Rectal plotgram and 3d graphical representation provide a new tool in anorectal manometry. It points to the importance of rectum and give us better insight into the complex relation between rectum and anal canal in health and disease.