How Duodenal Switch Works
Duodenal switch packs a one-two punch against obesity. It does so by combining two surgical techniques: restrictive and malabsorptive.
The restrictive component involves reducing the size of the stomach. Your bariatric surgeon would divide the stomach vertically and remove more than 85 percent of it. The stomach that remains is shaped like a banana and is about 100 to 150 milliliters or 6 ounces.
Duodenal switch surgery is a variation of another procedure, called biliopancreatic diversion. But the duodenal switch leaves a larger portion of the stomach intact, including the pyloric valve, which regulates the release of stomach contents into the small intestine.
As the name suggests, the duodenal switch also keeps a small part of the duodenum in the digestive system. The duodenum is the first part of the small intestine. It is located between the stomach and the jejunum, or the middle part of the small intestine.
Foods mix with stomach acid, then move down into the duodenum, where they mix with bile from the gall bladder and digestive juices from the pancreas.
Malabsorptive surgeries restrict the amount of calories and nutrients the body absorbs. The malabsorptive component of duodenal switch surgery involves rearranging the small intestine to separate the flow of food from the flow of bile and pancreatic juices. The food and digestive juices interact only in the last 18 to 24 inches of the intestine, allowing for malabsorption.
Unlike the restrictive part of the surgery, the intestinal bypass part of the duodenal switch is partially reversible if you are one of the people who experience malabsorptive complications.
With the duodenal switch, you consume less food than normally, but it is still more than with other weight loss surgeries. Even this amount of food cannot be digested as normal, so a large amount of food passes through the shortened intestines undigested.
The duodenal switch can also be performed laparoscopically, meaning that your surgeon makes small incisions as opposed to one large incision. He or she inserts a viewing tube with a small camera (laparoscope) and other tiny insert instruments into these small incisions to perform the duodenal switch procedure.
Who is a Good Candidate for Duodenal Switch?
Once you and your physician have decided on weight loss surgery, the next step is to choose the best technique for your obesity. This is an individualized decision based on many factors.
If you have a body mass index (BMI) greater than 40, you may be a candidate for the duodenal switch. Others with lower BMIs, but with obesity-related illnesses such as diabetes may also be candidates for this procedure. A BMI takes height and weight into account to measure body fatness, and a BMI of 30 or higher in adults is considered obese. [Read more about body mass index, and measure your own with our BMI calculator.
The duodenal switch may be effective for people with very high BMIs of greater than 55. In fact, a study found that the duodenal switch produced more weight loss than the Roux-en-Y gastric bypass in patients with a BMI of at least 50.
That said, this complex surgery does have more complications and may not be the right choice for certain high risk individuals, including those with heart failure and sleep apnea. Talk to your surgeon to determine if the duodenal switch is right for you.
Pre-Surgery Considerations for the Duodenal Switch
Regardless of the surgical method chosen, preparing for weight loss surgery starts with making a lifelong commitment to the dietary and lifestyle changes necessary for success. Weight loss surgery is not a quick fix; nor is it a decision to enter into lightly.
Once you have made the decision together with your surgeon and your family members, the preoperative evaluations can begin. They include:
- Meeting with a registered dietician to discuss how your diet needs to change both before and after weight loss surgery.
- A comprehensive evaluation by a mental health professional.
- An upper endoscopy exam may be performed to make sure no polyps, tumors, ulcers or bacteria that cause ulcers are in the stomach prior to surgery.
- Additional pre-operative evaluations may be necessary for the heart and lungs.
It’s also wise to tell your surgeon about any medications you are taking or plan to take throughout recovery. Vitamins, minerals and herbs also interact with medications, so don’t leave anything out.
Some of the lifestyle changes start before surgery and include:
- Quitting smoking for at least six to eight weeks before and after weight loss surgery. Smoking can increase the risk of complications, including potentially fatal blood clots. What’s more, smoking also increases the risk of pneumonia and other lung problems after surgery.
- Not drinking alcohol for at least 48 hours before weight loss surgery.
- Losing 5 to 10 percent of excess body weight. People who lose a moderate amount of weight before weight loss surgery have a shorter hospital stay and more rapid postoperative weight loss, according to a study in Archives of Surgery.
What to Expect After Duodenal Switch Surgery
The duodenal switch operation is lengthy, often lasting three to four hours. Some surgeons may also choose to do it in two parts. Most people require about three to four weeks of recovery after undergoing duodenal switch surgery.
Part of the recovery process involves getting re-accustomed to eating solid foods. People who undergo the duodenal switch can consume only fluids immediately following surgery. From there, they will progress to pureed foods and ultimately solids.
Some people who undergo duodenal switch surgery do experience difficulty consuming liquids immediately after surgery because of swelling around the stomach and small bowel. In these cases, re-admission to the hospital for a day or two may be necessary to rehydrate.
Pain may also occur following duodenal switch surgery. Your surgeon will likely prescribe painkillers in the days afterward.
Most of the weight loss with the duodenal switch occurs during the first 12 to 18 months after surgery. Based on patient averages, you can expect to lose about 70 percent of your current weight and about 35 percent of your BMI.
The duodenal switch may result in more nutritional deficiencies than other weight loss surgeries because of the malabsorption it causes. As a result, you will need to take nutritional supplements, including vitamin A, vitamin D and calcium, daily for the rest of your life. Some doctors may also recommend additional supplements of potassium and iron. Lifelong nutritional follow-up is needed after duodenal switch.
Compliance with nutrition guidelines is absolutely mandatory for duodenal switch patients, because failure to comply can lead to malnutrition and significantly unpleasant bowel changes.
There are other nutritional considerations after undergoing duodenal switch. For example, eating fatty foods tends to cause foul-smelling gas and diarrhea. In addition, some very starchy foods may cause gassiness. Note that everyone responds differently to different foods, so your experience may vary.
Risk of the Duodenal Switch
All surgeries have short- and long-term risks. The short-term risks of duodenal switch include:
- Bleeding/blood loss
- Blood clots
- Leakage. A leak means that a perforation of the stomach or a leak from anywhere the bowel is stitched together has occurred.
- Difficulty in consuming liquids immediately after surgery, due to swelling around the stomach and small bowel.
The long-term risks of duodenal switch include:
- Nutritional deficiencies.
- The brittle bone disease osteoporosis, due to malabsorption of calcium and vitamin D, which are needed to maintain bone strength.
- Night blindness due to malabsorption of Vitamin A.
- Malabsorption of protein, leading to malnutrition. This may lead to a second operation.
- Carbs can be well absorbed, resulting in inadequate weight loss.
- Chronic diarrhea. You may have many loose bowel movements in a day. In the duodenal switch, your surgeon shortens the amount of bowel that the food goes through and diverts the digestive juices. The food goes through half of the intestines and then does not meet the digestive juices until the tail end of the intestines. This cripples the digestive process, resulting in diarrhea.
- Foul-smelling stools and gas.
Advantages of Duodenal Switch Surgery
Compared with other types of weight loss surgery, the duodenal switch has these advantages:
- The remaining stomach is much larger after duodenal switch surgery than following gastric bypass; this allows for larger meals.
- Reduced risk of developing ulcers.
- The intestinal bypass part of the surgery is partially reversible for those having malabsorptive complications.
- Possibly greater long-term weight loss and less chance of regaining weight.
- More rapid weight loss, compared with gastric banding procedures.
- More complete disappearance of obesity-related illnesses.