The omega loop
gastric bypass (OLGB) has become a very commonly performed bariatric procedure because of the advantages it carries over the
Roux en Y gastric bypass (RYGBP). However, mini
gastric bypass is a misnomer, as this procedure is more malabsorptive than the RYGBP. Recently, it is called single or one anastomosis
gastric bypass. The omega loop procedure is associated with a risk of
afferent loop syndrome, a known complication of the
Billroth II (Finsterer) operation. This rare complication of the OLGB can be debilitating, serious, and deadly.
Afferent loop syndrome should be suspected in case of
malabsorption syndrome with chronic
diarrhea,
steatorrhea,
iron-deficiency anemia,
edema,
emaciation, and
osteomalacia and also in case of simple biological anomalies such as macrocytosis or
megaloblastic anemia. The diagnosis can be confirmed by measuring bacterial overgrowth, although this requires a jejunal aspirate performed during endoscopy with jejunal intubation. A microbial population of more than 106 organisms per milliliter of aspirate is pathological.
Afferent loop syndrome is encountered less frequently now that the number of
gastrectomies has dropped. Yet, with the omega loop bypass procedure becoming more common, surgeons must again be made aware of this potential complication.