Basically this picture says it all... but if you want a specific detailed description... here it is (Copied from Chrysalisclinic website) : Hybrid Restrictive & Malabsorptive Bariatric
Procedures: Roux-en-Y Gastric Bypass Cesar Roux, a renowned Swiss surgeon, described the Roux-en-Y technique about a century ago, long before bariatric surgery had ever been contemplated. Basically, it makes use of a segment of proximal jejunum to function as a conduit to drain various parts of the upper gastrointestinal tract into the small intestine, thus ‘bypassing’ part of the gastrointestinal tract. Usually when this technique is employed in non-bariatric surgery, the loop used as conduit is about 40cm. In bariatric surgery the technique has been modified by making the Roux loop 120-200cm long.
The Components of the Operation
This Roux loop is anastomosed at its upper end to a very small pouch constructed from the upper end of the stomach and at its lower end, usually 150cm distal to the upper anastomoses, to the proximal jejunum where the bowel was divided to construct the Roux loop. (An anastomosis is the point at which two parts of the gastrointestinal tract are joined, in such a way that there is an opening between the two.)
The operation, therefore, comprises a small gastric pouch of 30-50ml capacity and a 150cm long Roux “alimentary” limb of small bowel that acts as a conduit for food from the gastric pouch to where bile and pancreatic juice now enter. As a result, ingested food is now only exposed to the digestive juices much lower down the small intestine and the length of bowel in which digestion of food and absorption of the nutrient components is greatly shortened.
The small gastric pouch has a restrictive function.
The long Roux loop adds a malabsorptive component, because food in that length of small intestine is not exposed to the digestive enzymes from the pancreas or the bile that facilitates digestion by those enzymes.
In addition, because the fundus of the stomach is by-passed, secretion of the hormone ghrelin that stimulates the appetite centre of the brain is greatly reduced and appetite is duly suppressed.
The Execution of the Operation
The mechanics and physiology of the operation were worked out long before laparoscopic surgery was developed.
In those days the operation was done via a laparotomy, using a large incision in the abdominal wall to obtain access to the stomach and intestines. Of course we can still do the operation in this way and, if for any reason laparoscopic surgery is not feasible, the laparoscopic operation can be converted to an open laparotomy or the surgeon can plan to do it open from the start.
Laparoscopic surgery really began in a big way in the early 1990’s as a result of technological advances in video cameras, etc. and the consequent development of instruments and techniques to do operations that previously were all done open.
Laparoscopic surgery involves making 4-6 small (5-12mm) incisions in the anterior abdominal wall, through which plastic or metal ports are inserted into the abdomen. The abdominal cavity is distended by insufflation of carbon dioxide gas into the abdominal cavity.
Then, a telescope connected to a light source and a video camera is inserted into the abdominal cavity through one of the ports. The surgeons, looking at a video monitor, are now able to see clearly inside the abdomen. The view is very well illuminated and magnified. However the field of vision is small and depth of field is lost because they are looking at a two-dimensional image as opposed to the three-dimensional vision they would see with their own eyes at open surgery.
The next step is to insert the instruments through the other ports. These instruments have very long shafts and very small working parts. The assisting surgeons hold the camera in position and retract tissues to give optimal visibility and exposure to the operating surgeon.
The Steps of the Operation
1. We first construct the small gastric pouch:
We identify the oesophago-gastric junction (OGJ) and mobilize the fundus of the stomach off the diaphragm.
Then we identify a point on the lesser curve (right edge) of the stomach 5cm below the OGJ and we cut through the attached fatty tissue to expose the posterior wall of the stomach. Once into this space (the lesser sac) we cut any attachments of the stomach to the pancreas.
We now insert a stapling device and place it across the stomach at right angles to the vertical axis, close the jaws and “fire” it. This cuts across the front and back walls of the stomach and staples the front wall to the back wall.
We complete the construction of the pouch with further firings of the stapling device from the end of our first staple line to the angle of His, the angle between the left side of the oesophagus and the fundus of the stomach.
During all this we take great care to avoid damage to, especially, the pancreas, spleen and oesophagus.
2. Division of the Omentum and Gastro-colic Ligament
We now find the lowest part of the omentum, a large “apron” of fatty tissue that hangs off the transverse colon.
We cut through the omentum, at right angles to the transverse colon.
After exposing the transverse colon we proceed along the same trajectory through the gastrocolic ligament, another fatty membrane that connects the greater curve of stomach to the transverse colon.
This is done to create space for the small bowel to come over the colon and bypassed stomach.
3. The Gastro-Jejunal Anastomosis
We now lift the transverse colon to find the duodeno-jejunal flexure and then grasp the proximal jejunum and bring it up over the front of the transverse colon and the lower part of the now-bypassed stomach
When we are satisfied the jejunum is lying comfortably and can reach the gastric pouch without tension we make a small incision in the loop of jejunum and another small incision in the staple line of the gastric pouch.
We insert one jaw of the stapling device into the lumen of the jejunum and the other into the lumen of the gastric pouch and when we are satisfied both are well into their respective lumens we close the jaws of the device and fire it. This results in a side-to side anastomoses between the gastric pouch and the jejunum.
After removing the device an opening is left, which we close by suturing the hole transversely to avoid causing any narrowing.
The anaesthesiologist pushes a nasogastric tube into the pouch while the surgeons watch to make sure it does not damage any staple lines. The anaesthesiologist then injects a blue dye while the surgeons occlude the jejunum to check for any leaks. If there is a leak it is repaired with a suture. If there are no leaks the anaesthesiologist advances the tube into the efferent (alimentary) limb and fixes the tube to the patient’s nose.
4. The “Y” Jejuno-Jejunal Anastomosis
We now measure out the 150cm alimentary limb in 10cm segments.
We then stitch the intestine at the 150cm mark to the proximal jejunum between the duodeno-jejunal flexure and the gastrojejunal anastomosis.
We make incisions in the two loops of bowel we have now aligned side by side and we anastomose the two, side-to-side, by suturing the one incised loop to the other incised loop.
5. Completing the Roux loop
The short segment of proximal jejunum between the gastrojejunal and jejuno-jejunal anastomoses is now exposed and divided by placing the stapling device across the bowel and firing it.
6. Closing the Mesenteric Windows
In constructing the Roux-en-Y bypass we create a window between loops of bowel. Other loops of bowel could, potentially, slip into this window and become obstructed. We, therefore suture the mesenteries of adjacent loops of bowel to each other to close this window.
The Post-operative Period
The standard practice is for the patient to be taken back to our GIT Ward after the patient has recovered from the anaesthetic. Only if the patient is at particularly high risk for cardiac or respiratory problems does he or she go to the high or intensive care unit.
In the GIT Ward the patient will have a nasogastric tube (in the nose), a tube in the bladder (urine catheter) and a drip in the arm.
As soon as the patient is awake enough the physiotherapist will get him/her out of bed and for a walk. This will be repeated later in the day.
On the following day, if the surgeon and critical care physician are satisfied that all is well, the nasogastric tube and urine catheter will be removed and the patient will be allowed to sip small volumes of water. If the patient tolerates this well, the volume of the liquid allowed is gradually increased.
The staff keeps a close look-out for any problems developing and if things do not go smoothly blood tests and or X-rays may be done. If the surgeon is concerned about a leak or bleeding he may decide it is necessary to take the patient back to the operating room to be re-explored.
If all goes well and the escalating volumes of oral fluid intake are tolerated, the intravenous fluids are discontinued and a liquid diet is introduced.
Usually after 2-3 days the patient is ready to go home with some pain-killers and some iron and vitamin and mineral supplements. In many diabetic patients their diabetic medication requirements are greatly reduced from early after the operation.
For the first month the patient is strongly advised to only drink liquids and pureés to avoid any risk of the staple lines holding the newly re-arranged gastrointestinal tract from disrupting.
The patient is encouraged to keep in regular contact with the dietician to ensure he/she is taking enough protein, water and fibre and does not become constipated.
Unless there are problems with the wound or anything else relating to the operation the patient usually sees the surgeon for a check-up after 3-4 weeks, as well as the endocrinologist to review the status of the blood glucose and lipids blood pressure, etc.
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