Roux-en-Y Gastric Bypass
Roux-en-Y gastric bypass (RYGB) was first reported in 1967. The surgery divides the stomach into two compartments. The small upper compartment also known as the gastric pouch (typically 30ml in volume) receives food. The lower compartment is “bypassed” and does not receive food. The small intestine is then divided. The lower end the divided small intestine is brought up and connected (“anastomosed”) to the gastric pouch. The free end of divided small intestine is then connected to the "Roux" limb (the loop of intestine was that up brought up to join the gastric pouch) at around 50-150cm from the 1st connection (anastomosis).
Gastric bypass works by small gastric pouch restricting the amount of food that can be eaten. Additionally, bypassing distal stomach and first part of small intestine causes metabolic and hormonal changes that lead to reduced appetite and an increased feeling of fullness. Gastric bypass patients typically lose around one third of their total body weight in the first 2 years. Obesity related diseases, particularly diabetes, will typically improve after surgery.
Several long-term problems are associated with gastric bypasses. Vitamin and mineral deficiencies are common, particularly iron, vitamin B12, vitamin B1, calcium, zinc, vitamin D and folate. Therefore life-long surveillance and vitamin and mineral supplementation will be required. Ulcer formation at the connection between the gastric pouch and the small intestine (marginal ulcer) had been reported in 1-16% of bypass patients. Marginal ulcers could bleed or perforate. The management of these chronic ulcers is challenging as they are often resistant to various treatments.