Duodenal Switch DS vs RNY


The Restrictive Component

The Differences Between the BPD/DS and the RNY Procedures

In researching which type of weight-loss surgery to pursue, people often want to know the differences between the BPD/DS procedure and the more common Roux-en-Y procedure. Several people have written their own comparisons, which are listed below. By reading these folks' "take" on things, you may gain a greater understanding of exactly how the BPD/DS works.

By Laura E. in Phillips Ranch, CA

It's not easy to understand the differences between these surgeries! Hopefully, you've had a chance to read up on the ASBS site -- they have a paper there that gives some good info about the various surgeries that are done for obesity. Also, Drs. Anthone and Rabkin have excellent information on their websites that show diagrams and details of the Duodenal Switch procedure. [See the More Information page for these URLs.]

All weight loss surgeries work by making the stomach smaller (restrictive procedures) and/or creating changes in the digestive tract which do not permit the body to absorb all of the fats in the food you eat (called malabsorptive procedures).The DS is a combination restrictive and malabsorptive surgery. The stomach is made smaller and the intestines are rerouted so that you can't absorb all the food you eat. Because of this malabsorption it's essential that you monitor your vitamin levels and take your prescribed vitamins for the rest of your life. It's also the malabsorption that can cause diarrhea if you eat too much fat. The undigested fat in your colon can cause gas problems, but they usually improve in the first 6 months after surgery.

The DS is similar to the RNY with respect to the intestinal bypass (malabsorptive) portion of the procedure. The lower part of this surgery is basically the same as a distal RNY. RNY's are done either proximal (with a shorter length of the intestines bypassed) or distal (with more of the intestines bypassed). Studies have shown that people who have distal bypasses have greater success at losing large amounts of weight and keeping it off.

The RNY and DS are very different with respect to what is done at the top end of the surgery -- the portion involving the stomach (the restrictive aspect of the surgery). The RNY doctors do a variety of things to make the stomach smaller -- most create "pouches" or transect (divide) the stomach. They then reroute the intestines by connecting them directly to the new stomach pouch, bypassing the duodenum. In the RNY/pouch procedures, the pyloric valve (which regulates the emptying of stomach contents into the duodenum) is bypassed and therefore doesn't function after surgery.

In the DS procedure, the surgeon creates a smaller stomach by removing about 75% of the stomach (which is called a partial gastrectomy). The top part of the gastric bypass is connected below the duodenum which keeps the upper part of the digestive process the same as before surgery (except that your stomach is smaller). Your pyloric valve continues to regulate the emptying of the stomach contents into the duodenum and all of the hormones and secretions that occur in the duodenum continue after surgery.

In RNY/pouch procedures, the duodenum and pyloric valve are bypassed and the intestines are connected to the newly created stomach pouch. Dumping happens when the stomach contents (unregulated by the pyloric valve which has been bypassed) dump directly from the new stomach pouch into the intestine. Eating sugars can cause dumping for many RNY/pouch patients. For this reason, they must be very careful of sugars. Some feel that this type of surgery with the dumping syndrome is the best option for people who eat a lot of sweets, since the dumping acts as a deterrent to eating sweets.

Since our pyloric valve and duodenum are left functioning as before, we DS patients don't have dumping syndrome, nor a risk of staple line problems, clogging of the anastamosis, ulcers at the stoma, etc. (remember, we don't have pouches or stomas). So, we don't have the problems with "stretching" the pouch or getting something stuck in the stoma -- because what we have is our real stomach, connected the same way it was before surgery to the duodenum.

Good luck in sorting all of this out!! Of course, I'm biased but I believe the Duodenal Switch is the best surgery for morbid obesity!

Laura E. in Phillips Ranch, CA.
DS/DGB 3-5-99 Dr. Anthone, USC, Los Angeles
Pre-op wt. 418 lbs, 5'7" age 45
Lost 75 pounds as of 4 months post op.

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By Craig in San Francisco

There are always a lot of questions about the difference between the Distal Gastric Bypass with Duodenal Switch (DS) and the more common Roux-en-Y (RNY) procedure. I have done a fair amount of research for myself and can tell you why I have chosen the DS procedure. The following is just my understanding and opinion.

Probably foremost is that the DS avoids altogether the complications with the RNY "anastamosis" -- that is the artificial outlet from the "stomach" pouch into the intestine. Some RNYers have had this opening "close up" on them, sometimes several times. At the very least, this means a very painful trip to the emergency room to have the opening "roto rootered" open again. Unable to eat or even drink water, you can get into trouble quickly.

In the regular RNY, a small pouch is created where the stomach meets the esophagus, and made into a new artificial stomach. The remaining stomach is either stapled off or separated from the pouch. A hole "about the diameter of a pen" is then made in the pouch, and a fresh-cut piece of small intestine is brought up and sewn to that hole.

The opening between the pouch and the intestine is called the anastamosis. Food can block this small opening, or scar tissue can swell it closed. It is also prone to ulcers and bleeding (and internal bleeding is serious), because the "cast iron" tough stomach tissue both is largely impervious to, and itself produces acid, while the tender intestinal tissue sewn to it is neither. [The stomach tissue is a naturally acid environment, while the intestinal tissue is alkaline -- which can make for less-than-chummy bedfellows.]

Another concern is that because the exit from the stomach to the intestine is simply a "hole," from which the stomach contents empty directly into the intestine, it is like a sink whose drain is always open. For this reason, RNY patients sometimes have trouble regulating blood sugar, which causes the very unpleasant "dumping syndrome."

The Duodenal Switch procedure is essentially a newer, arguably more advanced version of the RNY, which avoids all of the above-mentioned problems. DS surgeons are still few and far between. Most DS surgeons have done a many RNYs and have been ultimately dissatisfied with the procedure, which led them to perform the DS.

The DS procedure includes a "distal" gastric bypass, which means that more of the small intestine is by passed than in a "proximal" bypass, which some may worry about. (The RNY can be done with either a distal or a proximal bypass.) The DS's distal bypass means that fewer nutrients and calories are absorbed than with a proximal bypass. This results in more successful weight loss, but it also means more vigilance is necessary in taking your vitamins and calcium supplements.

[After the DS procedure, patients will continue to absorb sugars completely, so it is important that we consume high-sugar foods in moderation. Proteins and carbohydrates will be absorbed incompletely at first, but the body will acclimate and absorb more of these nutrients with the passage of time.] Fats will never be completely absorbed following the DS, which means that eating high-fat foods can mean smelly and loose bowel movements. (But whose having surgery to keep eating lots of greasy foods?).

The biggest advantage of the DS is that you keep an honest-to-goodness stomach, [which is usually 150-200cc is size (as opposed to the 15-30cc pouch of the RNY)]. The pyloric valve remains intact and functioning just the way God intended it. The pyloric valve is a sphincter muscle that opens and closes to regulate the release of stomach contents into the digestive tract. The retention of the pyloric valve eliminates the dumping syndrome that is experienced by many RNY patients. The DS patient's stomach can also "churn" food like it is supposed to. DS patients do not have problems with bleeding ulcers or blocked "anastamosis." They are also less likely than RNY patients to vomit unexpectedly.

The bypass portion of the operation is essentially the same as a regular RNY - the top part of one side of the "Y" brings the food down, but has been disconnected from the pancreatic juice and bile. The other top half of the "Y" brings down only that pancreatic juice and bile. They food and digestive juices mix only in the bottom part of the "Y," which results in a greatly abbreviated digestion time.

The RNY is a great operation. It is the one performed by the greatest number of surgeons, and I would not hesitate to undergo it if the DS were not available to me for whatever reason. These surgeries are the best kept secret in medicine, saving lives both figuratively and literally.

Craig in San Francisco
Duodenal Switch 2-9-99, Dr. Rabkin
Pre-op, 410 pounds, 5'13" tall
-100 in 5 months!!!

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