DUODENAL SWITCH  

Sleeve Gastrectomy (Vertical Subtotal)+
Bilio-Pancreatic Diversion =
Duodeno-ileal Switch
   
WLS (Weight Loss Surgery)
For
MALIGNANT (MORBID) OBESITY

A patient information booklet
January 2008
Aniceto Baltasar, MD, FACS, FASBS
Cid 61
03808 – Alcoy. Alicante. Spain

WHAT IS THE DUODENAL SWITCH?
  The Duodenal Switch is a combination of two types of surgeries developed over the last 45 years to treat obesity.

1. Sleeve Gastrectomy or Part I(always done) is restrictive, reducing the stomach size 80% so the individual will eat less, and
2. BPD (Bilio-Pancreatic Diversion) is the  mal-absorptive component, or Part II reducing the small bowel’s ability to absorb ingested foods.

It is a mixed or hybrid type of surgery. Neither of the procedures is extreme; it is designed this way to lessen the undesirable side effects.

ANATOMY OF THE DIGESTIVE SYSTEM

Starting from the top we will explain the anatomy of the digestive system to understand how the operation works:

Digestive system	Abdominal organs	Duodenal Switch

 1.- Mouth: Entry point for food; teeth and tongue chew food and move it to the back of the throat for swallowing. The enzyme amylase starts digestion of starches and sugars (carbohydrates).
2.- Esophagus: Carries food to the stomach. It has no digestive function.
3.- Stomach: Holds food and mixes it with acid and saliva. It has not absorptive function!.
4.- Pylorus: The valve that controls the emptying of the stomach. It helps prevent “dumping syndrome”.
5.- Small bowel: This tube,5 meters (15-30 feet) in length, lies in between the pylorus and the large bowel (the colon). 95% of all digestion is carried out here and it is the most important part of the digestive system. It is divided in 3 parts:

• Duodenum: Two feet long (60 cm). Bile from the liver and pancreatic enzymes (the digestive juices) enter this segment.
• Jejunum: The middle portion of the small bowel.
• Ileum: The lower portion.

  The jejunum and ileum are the sections where carbohydrates, proteins and fats are absorbed, as well as vitamins and minerals. Iron and Calcium are absorbed in the duodenum.
6.- Large bowel: Starts at the end of the small bowel. Its main function is the absorption of water and holding the stools. Nutrients are not absorbed here. The appendix joins the bowel at its beginning.
7.- Liver: Nutrients absorbed from the small bowel go the liver via the portal veins. It secretes the bile necessary for fat digestion.
8.- Pancreas: Secretes the enzymes necessary to digest carbohydrates, proteins and fats.

HOW DIGESTION WORKS

Digestion stars in the mouth with saliva’s amylase. Food travels to the stomach where it is held, and mixed with acid, it starts to break down here. Stomach emptying is regulated by the pylorus. Digestion and absorption happen in the small bowel when food is acted upon by bile from the liver and pancreatic enzymes. Water is absorbed in the colon and waste is excreted through the rectum.

HOW THE BPD/DS IS PERFORMED ?

I.  Sleeve Gastrectomy (Vertical Subtotal): The restrictive part:
The stomach is transected at the greater curvature, leaving the functional inner portion of the stomach at a capacity of 60-120cc or 2-4 ounces. The Pylorus, the valve that regulates stomach emptying, is preserved. The stomach will probably double in size with time. We do not use bands or rings to narrow the stomach.
To cut the stomach, we use surgical linear staplers. These are instruments that apply staples and cut the bowel, both, at the same time. The staples make the operation safe, so bleeding and leakage are prevented!.
The duodenum is cut at 1 inches (2.5 cm) past the pylorus with linear staplers.  
II. Biliopancreatic Diversion: The mal-absorptive part.  
The cecum is identified and the appendix removed. Starting from the end of the ileum, where the small and large bowel meet, the whole small bowel is measured. It is cut half way (eight to nine feet = 250 cm) with the stapler.
The free end of the ileum is joined by stitches or staples to the short piece of remaining duodenum, 2.5 cm past the pylorus. This portion is now called the AL (Alimentary or Digestive limb).This is where the term “switch” comes from; as the ileum is switched to join the duodenum just below the stomach.
The remaining length of the duodenum and proximal small bowel, called the BPL (Bilio-Pancreatic limb) is attached to the ileum two and half feet (65 cm) from the ileo-cecal valve. This last portion of the “new small bowel” is called the CC (Common Channel or Common limb)
The AL has the ability to digest sugars and proteins but the full digestion takes place mainly in the common limb where all the pancreatic and digestive enzymes and bile mix with food. This part of the bowel is too short to absorb all of the ingested fat.

Advantages of this operation:

The small stomach restricts the intake because the patient easily feels full. But there is not any restrictive band to act as a foreign body to make you vomit. Not one inch of the small bowel is removed, so that portion of the operation is reversible. The removal of part of the stomach is not reversible, but with time the stomach enlarges enough to allow fairly normal intake and have no serious long-term consequences. The bile and pancreatic juices are reabsorbed and not lost from the body. The operation works by combining the restrictive and malabsorptive components. Either method alone will not cause weight loss. However, if you can’t eat as much as before and part of the food is not absorbed, you can’t stay fat.
The operated patient will absorb less calories than she/he needs. The body will use the accumulated fat within your body to compensate for the lack of calories. Weight loss will occur. Stored fat is burned and the byproducts, mainly cholesterol, are removed from your body by the liver and bile. With rapid weight loss, there is a high risk that cholesterol stones will form in your gallbladder. For this reason, we remove the gallbladder at surgery; otherwise, the patient will very likely have biliary colic and complications, that will require a gallbladder operation later on. A prophylactic cholecystectomy prevents this occurring.  
The full name of the operation should be “Sleeve Vertical Subtotal Gastrectomy/ Bilio-Pancreatic Diversion/ Duodeno-ileal Switch”. The short form is BPD/Duodenal Switch. and the shortest BPD/DS or just DS. Strangely enough the name of the operation has not been standardized and, still less, there is not coding for this operation, so most  Insurance Companies do not cover expenses.

IMPORTANT FEATURES OF THE D.S.

• The stomach: It will be small, 1.5 oz. (50 cc) in size, like a small juice glass (in the shape and size of a small banana); it will slowly enlarge so you can eat a small normal meal. Not a large meal. The segment of stomach removed is not reversible but it has very little clinical significance.
• Reduced incidence of marginal ulcers: Ulcers occur when the small bowel is joined to the stomach in the gastric bypass. Because the acid production has been decreased by the removal of part of the stomach the chances of ulcer formation is minimal.
• No dumping syndrome:This complication is caused by liquids and foods high in sugar content emptying into the small bowel as in the gastric bypass. It causes dizziness, sweating and such bad sensations that patients tend to avoid eating sugars.
• The pylorus: It is not removed or bypassed. It continues to function normally, controlling stomach emptying, preventing the “dumping syndrome” that occurs with the gastric bypass. It also allows complete and effective reversal of the small bowel no normal, if needed.
• The Alimentary limb: This is the distal small bowel, now joined to the duodenum. It digest mainly sugars and some proteins and ends in the common channel.
• The Bilio-Pancreatic limb: This is the first segment of the normal small bowel that now has no contact with food. It functions by reabsorbing bile salts and water as before the operation.
• The common channel: This is the last portion of the small bowel. It is the only segment available now to absorb FATS. But the remaining length is not enough. There is decreased amount of fat, cholesterol and triglycerides absorbed. The fat-soluble vitamins – A, D, E and K may be insufficiently absorbed as well. Patients are required to take supplements of these nutrients for the rest of their lives.

 
SUPPLEMENTS REQUIRED AFTER SURGERY

VITAMINS:
Vitamin A is important for your eyes and skin.
Vitamin D is important for calcium absorption and bone formation.
Vitamin E has not important clinical significance.
Vitamin K helps in coagulating your blood. Let your doctor now if you have to take “blood thinners”.
If you are not taking ADEKs you should take a Multivitamin each day, any one over the counter. It will supply most of the other vitamins and trace minerals.

CALCIUM
Since the proximal bowel is bypassed you will not absorb enough calcium. You must take calcium supplements, about 1500-2000 mg a day. “Tums” will work well in the 1st few weeks after surgery they are easy to take, help settle your stomach and reduce gastric irritation. Later, when you can take pills more easily start with “Cicatral” (Calcium citrate) or “Cal apatite” (the microcrystalline hydroxy-apatite is the most readily absorbed form of calcium).
Calcium carbonate is the most common form of calcium supplements on the market but it requires acid to dissolve, since your stomach acid output is now low any other type of liquid or vitamins will be absorbed better. Skim milk is a good source of calcium (300 mg per cup).

Calcium is the most important mineral for you after surgery. Most of the body’s stores are in bones, which are very important for your strength, function and body stability. Calcium plays a vital role in many basic physiological processes, including blood coagulation, the sending of messages along the nerves, skeletal and heart muscles function, preservation of cell membrane integrity and permeability and certain glandular functions. Less than one percent of the body calcium is in body fluids, and the rest is in the bones.

If your blood calcium level becomes too low, the body will take the needed calcium from the bones, and in the long run your bones will become softer (Osteoporosis) and easier to break. This is more common in post-menopausal women. Cal apatite is 20% more absorbable than Tums and even more than Cicatral.

After surgery these are the four blood test your PCP (primary care physician) should do: Serum calcium, Alkaline Phosphatase and PTH (a hormone that regulates calcium metabolism) and Vitamin D25.

CHILDBEARING
Women of childbearing age who are having weight reduction surgery should use some type of birth control during the period of rapid weight loss (18 to 24 months). Maternal malnutrition may impair normal fetal development. All patients who are losing weight, at a rapid rate, are in some way suffering some form of malnutrition. Pregnancy should be postponed until your weight has become stable for some time. Women who become pregnant after WLS should receive specific attention from the surgical care team along with their obstetrician. Many patients have become pregnant after DS without any difficulty, but they do need to be watched more closely and they also need to make sure they are taking all necessary vitamins, minerals and proteins.

Folic acid, one of the B vitamins, has been found to prevent neural tube defects (NTD). Increased intake of folic acid reduces the risk of NTDs such as anencephaly and spina bifida (open spine) by as much of 50 to 70 % if women take enough of it before conception and in the early months of pregnancy. Take your multivitamins containing 400 mg of folic acid (the standard in most multivitamins) every day.
Many morbidly obese patients also have fertility problems, but after WLS they will frequently be able to become pregnant. Do not get pregnant until your weight has stabilized.  

RISKS AND COMPLICATIONS
Most patients do very well with the operation but there are risks. Short-term risks are the one seen in the hospital or during the first month after WLS. The risks of all surgeries are infection, blood clots, bleeding and pneumonia. All of them are important to us.
The complication we surgeons are very concerned about is a possible “leak”. A leak is a perforation of the stomach or the bowel from any place where a suture or staple is. The places where the stomach and small intestine are sutured are tested during the operation for leaks using a special dye called “methidine blue”. No patients exits from the OR with a leak since we test it several times. But leaks may occur thereafter. Not all leaks need reoperation if they are well drained. But you may require reoperation, prolonged hospital stay and important medical treatment. Fortunately this complication is not common. One month after WLS the risk of this complications is gone.
Wound abscess or pus is very uncommon unless you had a leak. Special measures are used to prevent wound infection or drainage during surgery. Some patients may develop a wound seroma made of  the subcutaneous fat that becomes oily after WLS; the treatment is partial opening of the wound and drainage.
We cut stitches on the second or third day, and use strips of tape to hold the wound closed to decrease scar formation.
Some patients have difficulty takings fluids in the very beginning because there may be swelling around the operated areas. You will stay on liquids the first 1 week, then 1 week on mashed/pureed food, and then after two weeks you may go on a normal diet.  

BLOOD LOSS
  Blood transfusions in primary WLS are very rare; however we do have blood in our bank. In WLS revisions there are more chances of bleeding from previous scars and adhesions of the bowel. We do not think that it is necessary for patients to store blood before surgery.  

LONG –TERM COMPLICATIONS
Long-term complications are related to the mal-absorption part of the procedure. Since fat is not properly absorbed the fat-soluble vitamins have to be checked, such as Vit. A, D & K. Take your ADEK vitamins. Plus calcium. All of them should be taken for your lifetime, forever. Eat high quality proteins such as fish, meat, eggs, milk and cheese.
Blood tests should be done every 3 months the first year, every 6 months the second and yearly thereafter.
Premenopausal women need extra iron to prevent iron deficiency anemia. Postmenopausal women may take estrogen to prevent osteoporosis. Consult your physician regarding hormone replacement therapy.
Liver cirrhosis and liver failure are not inherent complications of this operation such it was in the old jejuno-ileal bypass (JIB). When/if they occur it is due to active B or C hepatitis or previous cirrhosis, plus some form of malnutrition. In the DS there is not a blind loop of bowel and bacterial overgrowth as there was in the JIB.

DIARRHEA
Diarrhea is not universal to the DS. Some patients are even constipated. You can have larger stools due to increased undigested food. Normally patients have to go to the bathroom very early and then after breakfast. Some may go once or twice more per day. It varies from patient to patient. Some patients may need to slow the bowel’s pace by using Lomotil (prescription) or Immodium (over the counter). Also you may need a antibiotic such as Flagyl if diarrhea happens while traveling and bowel flora changes. For many patients, diarrhea stops when they go on to clear fluids for a couple of days. In severe cases of diarrhea, patients may need to enter the hospital and have IV fluids to treat dehydration.
When diarrhea has occurred because of a change in the normal bowel flora take “lactobacillus acidophilus”, “bifidobacteria” or “Ultraflora” dairy free. This may solve your problem completely.
Avoid sorbitol since this white, sweet, odorless, crystalline alcohol found in berries, fruits used as a sugar substitute is not absorbed in the GI tract; it gets into the large bowel, bacteria ferment it and form gas and loose stools. Eat whole wheat, pasta and rolls made without sorbitol.  

BAD BREATH
Some patients have the sweet smell of acetone on their breath and have good results by taking 10 mg of Reglan (prescription) at bedtime or 5 mg (1/2 tablet) during the day, 2-3 times a day as needed.  

FLATULENCE
For most people gas is a problem because it causes (sometimes painful) bloating and (often mortifying) odors. Everyone has gas. The average person generates 1 to 3 pints of gas a day, but some people produce a lot more. The average is 14 times a day. Most gas is odorless.
Gas is composed of hydrogen, nitrogen and carbon dioxide and some oxygen. One third of the adult population produces copious quantities of methane, while the rest little or none.
Less than one percent of the gas smells. But boy, does it ever. Several sulfur containing compounds are responsible for most fecal odors. The human nose detects hydrogen sulfide in concentrations as low as one-half pert per million.
Certain foods are gassier than others. Beans, Brussels sprouts, raisins, apple juice and prune juice are a few. But a gas producing foods for one person may not be for the next. Extremely flatulent foods (more than 40 passages a day) vary from person to person. Carbohydrates are largely to blame, due to sugars, starches, and fiber that reach the colon (large bowel) without being digested or absorbed. Once in the colon, the colonies off harmless bacteria eat them and give off byproducts of hydrogen, carbon dioxide and in some people methane. These are the “good bugs” (bacteria) that are wiped out with antibiotics and need to be replaced by taking Ultradophilus, Ultrabifidus and lactobacillus acidophilus.
The most common sources of gas are: 1) lactose, a sugar that occurs in milk product. Many people lack the enzyme (lactase) to digest lactose: 2) Soluble fiber, like the pectin in fruits and the beta-glucans in oat bran:  3) Gas producing bacteria feed off small amounts of starch that escape digestion by enzymes in the small intestine. 4) The most infamous source of gas (in large amounts) is beans, vegetables and grains. No one has the alphagalactosidase enzyme required to break them down. When they hit the large bowel, our bacteria have a feast.  

FOLLOW UP
After surgery you will be given discharge information for your primary care physician and your self. It is very important that you follow up with your PCP, and  your WLS doctor, who understands  your type of surgery.
In our experience, DS is the operation that requires the lowest rate of revisions due to failure of the technique to lose enough weight or long-term secondary effects.
Patients should have blood tests every 3 months during the first year to detect any possible side-effects of the DS such as:  
1.  Protein malnutrition: Monitor Total & Albumin blood tests.
2.  Iron deficits: 7% incidence. Check Iron levels, anemia.
3.  Calcium deficit: 8% incidence. Follow Ca levels, Alk. Phosphatase, PTH and Vitamin D25.
4.  Diarrhea: 2% incidence. Controlled with Lomotil or Flagyl (Metronidazol).
5.   Fat soluble vitamins: A, Carotene, K (INR). Very low incidence (<2%).
6. Liver profile: SGOT & SGPT are normally elevated up to 60 units for the first 6 months. Total Bilirubin.  

WEIGHT REGAIN

    BPD/DS patients may lose weight for 16 to 18 months. The lowest weight the patients reaches it is called the nadir. Once the patient reaches the nadir of their weight there is always the chance that a particular patient may regain weight, but without any doubt this is the operation with the lowest weight regain!.
    Surgeons who have been doing this surgery for 12-14 years state that the mean weight regain is about 4-5 Kg = 10 lbs. A patient who has lived a lifetime with the terror of weight gain, it may call their doctors even, if the weight regain is less than 2 lbs. This is understandable. So far, in my experience, no DS patient has required surgical revision due to weight gain. The phenomenon of weight regain and reoperation was very common with the VBG.  

FOOD AND NUTRITION

• Protein: This is the most important food type. The body needs proteins for the most important bodily mechanisms. Since the intestine is shortened by half, and is the only place where proteins are absorbed, the patients should eat as much protein as possible. You will not gain any weight by eating proteins. Proteins are high in meat, tofu, meat substitutes, fish, shellfish, eggs, milk and cheese. The more you eat of these protein sources the better.
• Fat: The purpose of the bowel bypass is to decrease fat absorption. But there is little to no risk of deficiency of fat required for vital functions. Some patients lose fat in the stools; some  patients have reported seeing fat vacuoles in their stools.
• Carbohydrates: These foods are the cause of late weight regain, since simple sugars are easily absorbed. Carbohydrates are mainly found in candy, soda pop, cookies, pies, juices, sweetened drinks, ice cream, bread, potatoes, pasta, fruits and deserts. Try to avoid them.

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