Termsinsuk P, Chantarojanasiri T, Pausawasdi N. Diagnosis and treatment of the afferent loop syndrome. Clin J Gastroenterol. 2020 Oct;13(5):660-668.

“ALS is a rare condition with the incidence ranging from 0.2 to 1.0% depending on the type of operation and anastomotic limb reconstruction. ALS has been reported in 0.3–1.0% of patients after total gastrectomy with Billroth II or Roux-en-Y reconstruction, 1% after laparoscopic distal gastrectomy with Billroth II reconstruction, and 0.2% after distal gastrectomy with Roux-en-Y reconstruction [4–6]. Other operations of which ALS can occur include total gastrectomy with loop esophagojejunostomy with simple or pouch Roux-en-Y reconstruction and pancreaticoduodenectomy with conventional loop and Roux-en-Y reconstruction; nonetheless, the data on incidence were limited [7].”

Dumon K and Dempsey DT. (2019). Postgastrectomy Syndromes. In Charles J Yeo (Ed.) Shackelford’s Surgery of the Alimentary Tract, 8th ed.: 719-734. Elsevier, Philadelphia.

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“Afferent loop obstruction, also called afferent loop syndrome, is a mechanical complication that infrequently occurs following construction of a GJ. The creation of a GJ leaves a segment of proximal small bowel (duodenum and proximal jejunum) upstream from the anastomosis. With Billroth II or loop GJ the afferent limb conducts bile, pancreatic juices, and other proximal intestinal secretions toward the GJ 51 ; with Roux-en-Y the afferent limb conducts the succus toward the jejunojejunostomy and is also called the biliopancreatic limb. The operations most commonly associated with afferent loop obstruction are Billroth II and Roux-en-Y GJ (distal gastrectomy or gastric bypass), and Roux-en-Y esophagojejunostomy (total gastrectomy). 52 The incidence of significant afferent loop obstruction after these procedures is low (0.3% to 1.0%) and is similar after open and laparoscopic surgery.”

FIGURE 62.7. Causes of afferent loop syndrome include (A) kinking and angulation of the afferent limb, (B) internal herniation of the afferent limb behind the efferent limb, (C) stenosis of the gastrojejunal anastomosis, (D) redundancy of the afferent limb leading to volvulus, or (E) adhesions involving the afferent limb. (Modified from Miller TA, Mercer DW. Derangements in gastric function secondary to previous surgery. In: Miller TA, ed. Modern Surgical Care: Physiologic Foundations and Clinical Applications. 2nd ed. St. Louis: Quality Medical; 1998:402.)