Anal transitional zone and columnar cuff in restorative proctocolectomy

The popularity of double stapling the ileal pouch‐anal anastomosis probably owes more to the technical ease it brings than to histological considerations or functional results. It is preservation of a ‘columnar cuff’ of mucosa, rather than the restricted site of the anal transitional zone, that should be the focus of research with respect to long‐term risk of malignancy and inflammatory complications. If cancer is present in colon that has been removed for ulcerative colitis, there is a 25 per cent incidence of dysplasia in the columnar cuff in the short term. In other circumstances, those who are spared from carcinoma by colectomy are likely to have a similar risk of developing dysplastic change in the columnar cuff with longer follow‐up. Double stapling the pouch‐anal anastomosis and preserving the anal canal mucosa improves function, but long‐term surveillance of the columnar cuff is then required, including biopsies.