Efferent Limb Myoneural and Luminal Continuity and Postgastrectomy Gastric Emptying

Abstract

Delayed gastric emptying and altered upper gut transit or both are common following Roux-en-Y gastrojejunostomy and are thought to be due to altered efferent limb transit secondary to isolation of the Roux limb from the duodenal pacemaker. We postulated that preservation of myoneural continuity of the Roux limb with the duodenal pacemaker would enhance solid gastric emptying, while division of the afferent limb of a Billroth II gastrojejunostomy (B-II), isolating the efferent jejunal limb from the duodenal pacemaker, would slow gastric emptying. Solid gastric emptying was measured in 14 dogs, who then underwent gastric vagotomy and antrectomy. Eight animals were reconstructed with a Roux-en-Y gastrojejunostomy, preserving myoneural but not laminal continuity of the Roux limb with the afferent limb via a muscularis bridge, while six dogs underwent standard B-II gastrojejunostomy. Serosal electrodes were placed on the afferent and efferent jejunal limbs. Gastric emptying was restudied, with fed and fasted myoelectric recordings. The bridge was then divided to create a standard Roux, while the afferent limb was transected and reanastomosed just proximal to the gastrojejunostomy in the B-II dogs to isolate the efferent limb from the duodenal pacemaker, with repeat studies. Bridge dogs had delayed solid gastric emptying compared to their preoperative state, despite normal efferent limb motility. Gastric emptying was not further altered by division of the bridge, despite altered efferent limb motility, including a decreased migrating myoelectric complex (MMC) cycle length (62 ± 1 vs 128 ± 18 min, P < 0.001), slow wave frequency (SWF) (14.1 ± 0.6 vs 17.6 ± 0.6 cpm, P < 0.01), postprandial suppression of MMCs (60 ± 18 vs 303 ± 28 min, P < 0.01), and an inverted SWF gradient, indicating ectopic pacemakers. Solid gastric emptying was unchanged after standard B-II compared to the preoperative state, even following transaction and reanastomosis of the afferent limb. Solid gastric emptying was faster in the latter group than in Roux animals, despite similar efferent limb motility. We conclude that myoneural continuity of the efferent limb of a gastrojejunostomy with the duodenal pacemaker is less important than luminal continuity of the afferent and efferent limbs in determining postgastrectomy solid gastric emptying.