Article on Malabsorptive Procedures as it pertains to the Roux-En Y Gastric Bypass.
The Gastric Bypass procedure is considered the “Gold Standard” that all other weight loss procedures are measured against. The Gastric Bypass combines both gastric restriction and limited malabsorption to provide more weight loss and durable long lasting weight loss in most patients (90%). This is based on nearly 30 years of follow up in the Surgical Journals and countless studies with long term outcomes.
The volume of the stomach which normally holds two quarts of food (2000 cc) is reduced to less than one ounce (20 cc) by separating a small pouch from along the upper inner top of the stomach with a surgical stapler using a hard rubber tube to measure the pouch volume so it is always consistent. This is called a “Divided Bypass” where the pouch is completely separated from the lower stomach to prevent the staple lines from opening and allowing patients to regain weight. This change of dividing and separating the pouch away from the old stomach was made around 1995 and dramatically reduced the risk of late weight regain which occurred in 15% of Gastric Bypass patients prior to that time due to “staple line disruption”. The lower stomach is left in place for several reasons:
1) its always there if the surgery needs to be reversed (and yes the surgery is REVERSIBLE);
2) the stomach acid is needed to help with protein digestion,
3) removing the distal stomach would increase the risk of surgery and operating room time.
The small gastric pouch is reattached to the small bowel (Roux Limb) with a small measured opening of ½ inch or 12mm, which will cause the pouch to empty slowly. This combination of a small pouch and a small outlet is the basis of all modern weight loss procedures (Gastric Bypass, Laparoscopic Adjustable Gastric Band, and Gastric
Sleeve) and it relieves hunger (produces satiety) and causes weight loss by reducing the volume of food consumed (Restrictive Operation) and allows it to empty slowly to prevent over eating. If you over eat or eat too fast you throw up (Negative Re-enforcement or Behavioral Modification).
After the small gastric pouch is constructed the distal stomach and a portion of the proximal (upper) small bowel (100-150 cm or 4-6 feet) is bypassed to add some reduction in absorption of calories (Malabsorptive Operation) and improve weight loss and hunger control. In addition it alters the release of Incretins which are hormones produced in the small bowel to control blood sugar and leads to better control of insulin and usually resolves Diabetes in 90% of patients before they leave the hospital or lose any weight. This makes the Gastric Bypass a true Metabolic Operation and gives it a distinct advantage over Restrictive Operations. We divide the small bowel approximately 40 cm below the stomach and bring the distal end (Roux Limb) up to the pouch and reattach it with a small outlet of 12 mm which is measured and calibrated. The distal stomach and 40 cm of proximal small bowel are reattached around 100-150 cm below the stomach which delays the mixing of the digestive juices with food and reduces calorie absorption and fatty components like cholesterol and triglycerides. This forms the “Y” portion for which the operation is named. Food must be broken down and digested with this digestive fluid which is made up of stomach acid to digest proteins, bile from the liver to digest fats, and pancreatic enzymes to digest carbohydrates. The production of stomach acid, bile and pancreatic enzymes has nothing to do with food passing through the stomach but instead is stimulated when we taste or smell food, so this process continues even with the stomach bypassed.
All patients undergo a Gastroscopy during surgery where we inspect the staple lines under water and test them by pumping them up with air to test for leaks. Our leak rate after Gastric Bypass is extremely low (6/2400 = 0.25%), which is four times lower than most studies who report 1% leak rates.
All patients receive antibiotics before surgery and also blood thinner (Lovenox©) and special compression boots to massage the legs to prevent blood clots. The blood thinner and compression boots (SCD’s or Sequential Compression Devices) are continued throughout the hospitalization and frequent walking is strongly encouraged to also reduce the risk of blood clots and pneumonia.
The Laparoscopic Gastric Bypass normally takes approximately one hour to complete under general anesthesia. Patients remain in the hospital typically for two days and nights to insure they can tolerate a liquid diet and pain medication by mouth before discharge home. Patients describe the discomfort after surgery as “soreness” like being punched in the stomach, and not usually pain. Patients walk in the halls the day of surgery and have ice chips to keep their mouth wet and an IV to provide hydration. The next day we perform an Upper GI xray to test for leaks a second time and if it’s ok we discontinue the IV fluids and begin a low sugar liquid diet and oral pain medication. If they tolerate the diet and pain meds by mouth they are discharged the next morning. They are discharged with a prescription for pain medication (Percocet©) and a medication to reduce stomach acid (Nexium©) to prevent ulcers from forming as the stomach heals. Patients are instructed to take a multi vitamin, calcium supplement with vitamin D and if they are menstating females we also recommend an iron supplement. Gastric Bypass Patients are at risk for Iron, B vitamin and calcium deficiencies because the proximal small bowel (duodenum) is bypassed were these nutrients prefer to be absorbed. They remain on six small meals daily with a liquid diet and protein supplements for two weeks and then advance to a soft diet of cooked vegetables and fruit, fish, eggs and dairy products for weeks 3-6 and then resume a regular diet as tolerated. On discharge patients can walk, go up and down steps and drive a car when they’re off their pain meds. The only restriction is no lifting more than 25 pounds the first 3 weeks. After 3 weeks there are no restrictions. Patients normally resume their normal activity and return to work in one week as long as it doesn’t require lifting. Most patients are off pain meds in 5-7 days. Patients return to the office at 3 weeks, 3 months, 6 months and one year, and then yearly for aftercare. Routine blood tests and vitamin tests are performed at 6 months, one year and then yearly there after for life to insure good health.
The average Roux-en Y weight loss is 75% of a patients’ excess weight (the difference between their ideal body weight and what they weight before surgery) at one year and 90% of patients are successful at least 7 years after surgery in our experience.