LAUSR

Dear Editor: Surgery in Crohn’s Disease (CD) has always been based on the principle of limiting intestinal resection to the diseased tract as much as possible, thus saving precious centimeter of intestine for the patient. Traditionally, intestinal resection takes place by following the edge of digestive tube, keeping away from the vessels that go into the mesentery and the mesocolon, unlike cancer surgery which obliges the surgeon to respect the oncological principles. Recent studies have recognized the mesentery as a single anatomical and structural unit with functional properties that plays a role in both physiological and pathological mechanisms [1]. In particular, JC Coffey highlights that the main morphological changes of the mesentery (those detected intraoperatively by the surgeon): fat wrapping (or creeping fat) and mesenteric thickening are correlated with mucosal ulceration and degree of disease severity and that the mucosal ulceration is always confined to the mesenteric margin of the intestine. So he identifies the patobiological link of the disease in this connection: while signs of inflammation and edema extend circumferentially, the ulceration would be the result of the convergence of inflammatory inputs coming from both the submucosa and the mesentery [2]. How this issue can affect surgical practice? In a retrospective study [3], Toru Kono, with his antimesenteric functional end-to-end anastomosis, showed a lesser probability of anastomotic surgical recurrence in patients with CD who underwent Kono-S at 5 years (0% vs 15% p = .0013) than who underwent conventional anastomosis. The effectiveness of the new anastomosis in reducing the risk of surgical recurrence seems to be confirmed by the results of a multicenter study [4] where the 5and 10-year cumulative surgical recurrence rate was 1.8% (95% CI, 0– 4.3%) and 1.7% (95% CI, 0–4.2%) in Japanese and the US group respectively. It is possible to explain the low rates of surgical recurrence because, being the mesenteric side of the intestine the original site of anastomotic CD recurrence, to place anastomosis’ columns at the mesenteric side should prevent anastomosis distortion and maintain its diameter and dimension. The mesenteric side is placed at the center of the supporting columns, behind the posterior wall of the anastomosis; it is so excluded from the intestinal lumen. Thus, when recurrence of CD starts, it provides stable support which will prevent mechanical deformation. Shimada et al.’s recent study [5] strengthens the effectiveness of this type of anastomosis than classic end-to-end anastomosis in reducing surgical recurrence (3.4% in the Kono-S group and 24.4% in the end-to-end group) with a median follow-up of 54 months. Data suggest that the increased visceral adipose tissue (VAT) is involved in pathobiology of CD not only at molecular level (positive correlation with C-reactive protein, increase in adiponectin, adipocytokines, TNFɑ, IL10, and IL6) [6] but also at the clinical level since Li Yassociated it with Crohn’s disease activity and with an increased risk of postoperative recurrence [7], although it is not entirely clear whether the mesenteric fat hypertrophy is a primary or secondary phenomenon of intestinal inflammation. In his retrospective cohort series, CJ Coffey [8] showed how the inclusion of the mesentery as part of intestinal resection is associated with reduced surgical recurrence (the cumulative rate of reoperation in cohort A, mesentery sparing, was 40% and 2.9% in cohort B, mesentery excised) with a mean follow-up time of 69.9 ± 48.47 months and 51.7 ± 20.98 months, respectively. Furthermore, on a multivariable * Roberto Peltrini [email protected]