OBJECTIVETo evaluate influences on intestinal structure and myoelectric motility between modified uncut jejunal loop and Roux-en-Y procedures for biliodigestive anastomosis.

METHODSFifteen rabbits were randomized in modified uncut jejunal loop group, Roux-en-Y group and control group. Traced fasting slow-wave frequency (SWF) before biliodigestive diversion and 25 d postoperative (POD25) during laparotomy. Before the second laparotomy on POD21, the fasting SWF, percentage of abroad migrating myoelectric complex (MMC%), the postprandial spike potential frequency (SPF) and percentage of abroad propagation (SP%) were recorded in vivo. Compared myoelectric recordings according to parameters above. On POD90, harvested the stitched ligation of ascending loop and part of descending loop in uncut group, and biliary limb in R-Y animals, which assessed under HE, c-kit labeling immunohistochemical staining and transmission electron microscope(TEM).

RESULTSOn POD25, SWF declined mildly in uncut group (8.4%) and markedly in R-Y group (23.8%) respectively. The difference was significant (P<0.05). Before laparotomy on POD21 when abdomen closed, between uncut and control animals, there were statistical difference in fasting SWF and postprandial SPF (P<0.05), while no significance in MMC% and SP% (P>0.05). Moreover, differences of each parameters between R-Y group and control or uncut group were markedly statistical (P<0.01). Abroad myoelectric propagation through the ligated segment can be observed in uncut animals. Meanwhile, ectopic pacemaker was detected locating in the proximal segment of the Roux limb and triggering retrograde propagation in R-Y animals. On POD90, no recanalization were observed In uncut animals. Furthermore, occluded lumen with mild atrophic mucosa under microscope and c-kit labeling cells located in the inner circular muscle layer were observed, which proven to be Interstitial cells of Cajal (ICCs) by TEM. In R-Y animals, lumen of the Roux limb dilated. There's no significant difference in c-kit labeling area between R-Y and uncut animals by image analysis system. Reductions of processes and intercellular gap junction in ICCs, and loose interconnections between ICCs and SMCS or nerve endings were observed in R-Y animals.

CONCLUSIONSImpaired gastrointestinal motility after the Roux-en-Y procedure may due to the aberrant interstitial cells of Cajal. Modified uncut technique reveals a reliable and effective alternative for biliodigestive reconstruction.