Differences between RNY and DS

Both the DS and the RNY have two parts to the surgery - what is done to the stomach (restrictive part) and what is done to the intestines (malabsorptive part).

In the RNY, they section off the majority of the stomach which remains in the body, but unused (thus the term gastric bypass). Because this area is 'blind' - not accessible via oral medication or endoscopy, RNY'ers are advised to avoid NSAIDS or non-steroidal anti-imflammatory drugs such as aspirin, naproxen or ibuprofen due to the potential for ulcers for the rest of their life.

DS'ers don't have this problem because there is no blind portion - the unused part of the stomach is removed instead, so we can take OTC drugs. For people with *other* problems, such as lupus or migraines or a family history of ulcers, this can be an important factor in their decision.  Or even just getting older, where aches and pains come in to play.

The remaining portion (nicknamed The Pouch) is anywhere from 1-3 oz. (About the size of a large egg). This then feeds directly into a newly restructured part of the intestine with no valve regulating how quickly food moves from the stomach into the intestine.  Instead of a valve, there's simply a hole - kind of like a doorway - which leads into the intestines. This is called a stoma. The stoma is not flexible, so it cannot expand if you try to put something through it that is too big. This is why RNY'ers are told to chew their food VERY well, and are advised AGAINST having fluid with meals, because just like a sink drain, solid stuff will go down easier if you 'flush' it down with water.

Because there is no regulation there, three-fourths of all RNY patients suffer a syndrome called Dumping. For some people, dumping just makes them feel a little bad. Others vomit. Still others have a more severe reaction that feels more like a bad case of the flu, and a rare but potentially dangerous reaction can be like a diabetic attack.  Then, there is also the reactive hypoglycemia.  This can become very dangerous if you are driving a car for example, an pass out, which has happened.

Dumping Syndrome can be both a positive and a negative factor - if you immediately suffer a REALLY bad reaction to eating sweets, you're going to learn (the hard way) to avoid foods that aren't good for you. It's called Aversion Therapy, and if you learn better from the stick than you do from the carrot, this will keep you on the straight and narrow.

In the DS, they literally do a gastrectomy, removing the outer curvature of the stomach (making it physically smaller), but leaving the actual functionality of the stomach intact as it was before surgery. The remaining portion of the stomach is kind of "banana" shaped, and you start with about 3-5oz stomach - a little larger than the RNY, but still MUCH smaller than it is now.

You have multiple places in your body where you have a sphincter type muscle - the one everyone is familiar with is your anus, at the 'bottom' (pun intended) of your intestines. Well, you have a similar 'ring of muscle' at the pit of your stomach called the pyloric valve. Because this valve remains in use, DS patients do not have any dumping because the pyloric valve is still regulating how often food moves into the intestines as it does for you right now.

In both surgeries, the stomach/pouch will expand over time to about twice it's post-surgery size. This leaves long-term RNY'ers with about 3-5oz and long-term DS'ers with about 10-12oz.

Then we move into the lower portion of the surgery, which is essentially the same for both with a few small, but significant differences. The small intestine has three sections/phases - called the jujuneum, the illeum and the duodenum.

Right now, it is one continuous line. What they do is cut it in two and reattach them in a Y formation. One branch of the Y comes down from the liver with the digestive juices. The other portion comes down from the stomach (DS) or the pouch (RNY) with food. The two them come together into what is called the common channel which then has both digestive juices and food. It is in the common channel that most digestion takes place. (Some digestion takes place all throughout the whole digestive system, starting from saliva in the mouth, all the way to the colon)

The primary differences between the two in the lower part are this:

1) In the RNY, the common channel is generally longer - perhaps 275cm. In the DS, it's generally shorter - about 100cm. Everyone absorbs carbs like a non-WLS patient, but we malabsorb for protein, fat and calories - DS more than RNY, again due to the shorter common channel.

The 'big' problem this causes the DS'ers is too much fat can cause bad-smelling gas and/or diarrhea - and it's the one thing everyone who has every heard of the DS has heard of.  However, for MOST people, this isn't a huge problem, is easily controlled with products like Beano, and watching what they eat.  On the other hand, the RNY also has very smelly gas and/or diarrhea.

2) The Duodenum is bypassed in the RNY, and it is functional in the DS. What makes that important is that this is where protein, calcium, iron and vitamin B12 are absorbed. So even though the DS has a greater malabsorptive factor (the shorter common channel), it actually has more normal nutritional absorption than the RNY because the duodenum is still involved in the digestive process.

Now - BOTH types have to watch what they eat, and be aware that they are susceptible to nutritional deficiencies. For the most part, these can be controlled with diet, but if your diet is out of control, you can do *severe* damage to your health if you ignore this.

DS patients specifically need to make sure they take calcium & protein, and the fat soluable vitamins, in DRY form. RNY patients need to make sure they get protein, calcium, iron & B12. (Some need B12 shots, but not all). A person who has never had surgery needs about 60g of protein a day. RNY need about 80g. I've seen recommendations for DS patients of 90-120g.

Everyone should take a multi-vitamin, and get exercise, with or without WLS surgery. A low-carb, high protein diet is recommended to make sure you get in your protein, and you'll find LOTS of suggestions on what to eat on every board - both food, protein shake and supplement-wise.

Hope that helps.

Here is another link to a great post:

Comparison of Obesity Surgeries Turns Up Surprising Results
More popular method is less successful for maintaining weight loss, study says

http://www.obesityhelp.com/forums/ds/4570709/X-Post-Article-on-DS-versus-RNY/