Small intestine
It is approximately 1.5 cm in diameter in newborns after 35 weeks of gestational age, and 2.5–3 cm (1 inch) in diameter in adults. On abdominal X-rays, the small intestine is considered to be abnormally dilated when the diameter exceeds 3 cm. On CT scans, a diameter of over 2.5 cm is considered abnormally dilated. The surface area of the human small intestinal mucosa, due to enlargement caused by folds, villi and microvilli, averages 30 square meters.
Ileal interposition
In addition to sleeve gastrectomy procedure, the connection between the stomach and the duodenum is closed off from the level of the second segment of the duodenum. While preserving the last 30 cm part of the small intestine, a 170 cm segment of ileum is prepared and connected to the first segment of the duodenum, which is at the end of the stomach. The other end of the ileum segment is connected to the proximal part of the small intestine. Thus, distal part of the small intestine is ‘’interposed’’ between proximal part of the small intestine and the stomach. Since duodenum and the proximal part of the small intestine is disabled, a partial bypass is in question. Patients who undergo this operation achieve better weight and blood sugar control, but face anemia (iron deficiency) risk because of the bypass procedure.