Abstract

Three-dimensional, functional studies of the left colon using a polysiloxane foam enema have shown that three types of impressions due to muscular contractions are commonly found in the region of the rectum and sigmoid, and that at least two of these are closely associated with the presence of diverticular disease.

Each type of abnormality has been defined and its extent and frequency assessed. A tentative mechanism for the development of the main muscular abnormality through muscle thickening and simple sigmoid curves is put forward, and it is suggested that the third type of abnormality may be associated with sphincteric action at the recto-sigmoid junction.

The reproducibility of findings on repeated examinations must mean that there is a local anatomical basis for the muscular impressions seen and that such contractions do not represent evanescent peristaltic type activity.

Sigmoid resection and myotomy as practised for diverticular disease should eliminate the first type of abnormality in the majority of cases, but it is necessary to carry the operation well distally to ensure this. Neither operation is likely to correct the type III abnormality, and further work is necessary to determine whether this is responsible for some of the symptoms persisting after surgery.