[Capacity, motility and emptying of the ileal reservoir]

The ileal pouch design has been considered to be an important functional determinant. Whether reported differences are attributed to properties of a specific pouch or simply due to different length of ileum used for their construction is controversial. The pouch motility pattern has been considered to be another important functional determinator. There is evidence that pouches with a low volume threshold, i.e. those in which even a moderate volume distension generates high pressure waves, are associated with poor function. Manovolumetric data and results on the functional outcome carefully analyzed in our colorectal unit fail to support some of these statements. While the expanding property and volume capacity of the S- and K-pouch (design according to the Kock folding principle) are both superior to those of the J-configurated pouch the one year functional result appears quite similar. While ileal pouches which on distension exhibited vivid motility pattern generating high pressure waves were sometimes associated with poor function the observation was not consistent. Evacuation and sensory function of the pelvic pouch differ from that of the normal rectum. The motor compound of the defecation reflex is absent and patients evacuate by straining. Pouch design and motility only explain a fraction of the total variability in function. Factors like stool volume and consistency, and canal deformity, social habits and other patients related factors may also play an important role.