Duodenal Switch
Why One Surgeon Is Specializing In Duodenal Switch Procedure
The Roux-en-Y (Roo-n-Y) gastric bypass and the Duodenal (doo-a-deenal) Switch are two weight loss surgeries which involve drastically reducing the stomach and cutting and repositioning the small intestine.
But the Duodenal Switch procedure, which has a better average excess weight loss and allows you to eat more normally, is twice as complex as the Roux-en-Y gastric bypass, according to David Greenbaum, M.D., medical director of the bariatric surgery program at Lourdes Medical Center of Burlington County.
"You remove two-thirds of the stomach, transect the duodenum (first portion of small intestine connected to the stomach) and create a Roux-en-Y hookup. You also remove the gallbladder and appendix, so it is a much bigger operation," said the surgeon.
While he estimated that only 5 percent of bariatric surgeries are duodenal switches, that number is increasing as more surgeons like himself are trained in the procedure and offer it to patients, especially patients with a high BMI. (The BMI is a popular index, using height and weight calculations, to estimate health risk related to weight. The upper limit normal BMI is 25. See a BMI calculator here.)
The reasons he prefers the duodenal switch are numerous, Dr. Greenbaum said.
"The duodenal switch has the best weight loss, which is 80-to-90 percent of excess weight," he said. "It allows you to eat more than you can with the (Roux-en-Y) gastric bypass and you have normal digestion, but you malabsorb fat and carbohydrates, which helps with weight loss."
"If people cheat after having a restrictive operation like the gastric band, they gain 100 percent of the calories they cheat with. If they cheat with a Roux-en-Y gastric bypass, they still absorb a significant amount of the calories. But if you have a duodenal switch and cheat with fats or carbohydrates, for the most part you don't absorb them, don't gain the weight back and that's why the operation is best for really heavy people."
See a detailed explanation of duodenal switch surgery.
"The first part of the duodenal switch operation operation is restrictive because the stomach is made to be 120 cubic centimeters or about four ounces, down from 15-to-20 ounces, so consumption is restricted" said Dr. Greenbaum. "The second part bypasses so much of the small intestine that it is malabsorptive, meaning not all of the calories are absorbed."
There is a price to pay for eating the wrong foods, however. The average patient normally will have two to three bowel movements a day. "And if you eat carbohydrates in any significant quantity, that overload will go into the large intestine and produce gas the way beans would," said the surgeon.
Because of their complexity, Dr. Greenbaum said he usually performs duodenal switch procedures with a traditional open incision. He reserves the laparoscopic procedure for those patients who have much less excess weight to lose. The reason: Open duodenal switch procedures have a lower national mortality rate (.76 percent or 7.6 patients per 1000) compared to laparoscopic procedures (12 per 1000).
"When you do a laparoscopic procedure on a very heavy person, the way the table is shifted can create a tremendous amount of pressure on the gluteal (buttocks) muscles and hours of being in that position can create major problems," he said.
Before the duodenal switch became an option, the surgeon said he regularly performed Roux-en-Y gastric bypass procedures on high BMI patients.
"I did the Roux-en-Y gastric on people who were 500 pounds and they did great, but guess what, the ended up at 330 pounds, which is down 170 pounds but they were still 330 and that was a problem. I'm doing a revision Monday on just such a 330-pound person, revising his Roux-en-Y gastric bypass to a duodenal switch. We hope to get him down to 200."
A Detailed Look at the Duodenal Switch Procedure
The first part of the surgery, the reduction of the stomach into a narrow tube with a four-ounce capacity is the restrictive aspect of the surgery. The new stomach is fashioned from the upper stomach area that includes the pylorus, the valve that allows passage of the food into the small intestine. This allows for natural stomach emptying, said Dr. Greenbaum.
The second part of the surgery, a bypass of much of the small intestine, creates a malabsorption in which not all of the calories consumed are digested. This involves severing the small intestine about halfway down. The upper portion also is severed up top, where it normally connects to the stomach (the duodenum).
The stomach contents now need somewhere to empty. That is accomplished with the lower segment of severed intestine, the bottom of which already is connected to the large intestine. The top of this severed section is pulled up to make a connection to the stomach and pylorus to form the main channel from the stomach.
The top section of the small intestine, disconnected from the stomach, still receives bile and digestive juices from the liver and pancreas and it needs to be connected at it severed bottom. That bottom is attached (in a Y configuration) to the lower small intestine that is now receiving material from the stomach. This extra connection makes those digestive juices available as material comes through the small intestine on its way to the large bowel.
The surgery usually includes removal of the gall bladder and appendix. Gallstones may develop in the post-op obesity surgery patient and the duodenal switch surgery may make subsequent removal of gallstones difficult. The appendix is removed because digestion takes place on the right side and patients may later think that a pain in their right side is a possible problem with the appendix, said Dr. Greenbaum.
To locate a Lourdes Health System bariatric surgeon by phone, call 1-888-LOURDES.
