What to Expect from a VSG Revision to RNY or DSFebruary 22, 2017
The Vertical Sleeve Gastrectomy (VSG) is rapidly emerging as one of the weight loss surgery procedures that patients choose the most. For some bariatric surgeons and patients, the VSG has replaced the Proximal Roux-en-Y (RNY) Gastric Bypass as the most popular weight loss surgery currently done.
Removal of the upper outer stomach - the primary source of ghrelin (appetite stimulating hormone) production and pylorus preservation provide a more natural gastric restriction than the RNY or the adjustable gastric band (AGB). Most patients lose about 50-60% of their excess weight (%EWL) - not much different from what is typically reported after the RNY after five years.
Abnormal Weight Gain
Historically, about 25% of gastric restrictive surgeries, of which the Sleeve Gastrectomy is a prime example, may eventually require a revision to a different class of weight loss surgery. Despite using a fixed size bougie, there are infinite variations to how the Sleeve is created and this results in a variable geometry/ stomach capacity a few years out.
One of the first steps in assessing a patient who has either not lost adequate weight (defined as less than 50% of their excess weight) or has regained a significant amount of weight after a VSG is to determine - has the surgery failed the patient or the patient failed the surgery?
The pyloric valve is naturally designed to hold back solid foods such as protein and leafy green vegetables - foods that were all put on the planet for us to survive. The VSG relies on this valve for feedback and weight loss outcome revolves around the patient understanding this principle and utilizing it to its maximum potential.
However, most of the "foods" that we eat - such as liquids (including liquid calories), soft mushy foods, etc., bypass the pylorus. Given our busy lives, if a patient's staple diet is dominated by these foods, then gradual weight regain is inevitable and this has little to do with the operation. Once the clinician determines that validity of the patient factors contributing to weight regain, the next step is to assess the anatomy and functionality of the VSG.
Grounds for a Revision of the VSG
Creating a VSG brings the naturally stretchable upper portion of the stomach (the fundus/body) in direct proximity to the muscular lower portion of the stomach (the antrum) that does not stretch very much. Over time, despite the best efforts of the surgeon and patient, the upper half (or 2/3rds) of the sleeve can dilate significantly. This can be assessed by performing an upper gastrointestinal (UGI) endoscopy - which enables the surgeon to "look" inside the food pipe (esophagus) to check for reflux, the stomach remnant to get an idea of the size, both the upper and lower halves of the VSG, obtain tissue samples (biopsies) to check for pre-cancerous changes (Barrett's esophagus) and bacteria that could cause ulcers (Helicobacter pylori or H. pylori).
The next phase of the assessment is to check the functional aspects - patients would consume a measurable solid meal - e.g. garbanzo beans, ground beef, egg salad, etc., mixed with some barium (sorry!) until they feel full and they would be evaluated by a radiologist using an upper gastrointestinal (UGI) fluoroscopic study (barium swallow) to assess how much a patient can eat before they feel full (in ounces) and how does the stomach remnant look when it is distended maximally - in other words, its geometry.
Most patients with an adequately created Sleeve would feel full after 4-5 oz of solid food. Anything in excess of this, together with an outstretched upper portion of the Sleeve is grounds for revision of the VSG.
Depending on the patient's disease burden (excess weight above ideal body weight), weight loss expectations, clinician's assessment of the patient's post-surgery compliance with nutritional supplements, converting the VSG to a malabsorptive operation such as the traditional Duodenal Switch (DS) or the more recent variant of the DS - Duodenal Switch Single Anastomosis (DS-SA) may be necessary.
These operations involve a transection of the duodenum just beyond the pyloric valve and redirecting the food to the lower half of the intestine (the "alimentary limb (AL)"). The upper half of the intestine does not come into contact with the food but serves to divert and dilute the digestive juices (bile and pancreatic juice) (the "biliopancreatic limb (BPL)").
Absorption of calories and nutrients is confined to that segment of the AL that comes into contact with the diluted digestive juices (the "common channel (CC)"). This creates a "ceiling" on the amount of calories that can be absorbed on a daily basis which provides for about 20% better weight loss (i.e., about 70-75% EWL) than what can be typically achieved with a gastric restrictive surgery such as the VSG.
Diabetes remission rates are reported to be ~90% after the DS/ DS-SA.
Directing the food into the lower half of the intestine promotes secretion of appetite suppressing hormones such as PYY (polypeptide YY) and GLP-1 (glucagon-like peptide 1) which play an important role in better weight loss, weight maintenance and diabetes control.
Taking Additional Nutritional Supplements are Required
One of the inevitable consequence of this anatomy is that patients need to be compliant about taking additional nutritional supplements - protein, vitamins (especially fat-soluble vitamins - such as Vit D, A & E), Vit B12, calcium citrate, iron, zinc etc to decrease the risk of clinically significant nutritional deficiencies. They must also be compulsive about obtaining surveillance laboratory studies and follow-up with the clinician. Diverting food from the proximal portion of the intestine (duodenum and jejunum) areas which are naturally designed for efficient absorption of certain nutrients such as iron, calicum, and Vit D, increases the risk for anemia, bone loss (osteopenia and osteoporosis) and kidney stones.
Maintaining adequate core muscle strength and muscle mass by maintaining an active life-style, weight training, staying well hydrated etc would be the best way to mitigate this problem. Shortening the small intestinal exposure to food does carry some adverse consequence - such as gas, frequent stools and odor issues - believed to be from bacterial breakdown of partially digested food within the large intestine or colon. These problems are typically associated with consumption of carb rich foods. Most of these malabsorptive symptoms get better with time as patients adapt to the malabsorption and can be controlled with over the counter products. Choosing an operation such as the DS-SA variant which has a longer CC (10feet vs 5 feet with the traditional DS) can decrease these problems without significantly affecting the short-term outcome.
Gastro-esophageal Reflux Disease (GERD)
GERD symptoms including heartburn, reflux, difficulty swallowing and keeping down solid foods can occur in ~10% of VSG patients. While in the vast majority of patients these symptoms improve over time, in some they do not despite being on proton-pump inhibitors (PPIs) such as omeprazole and other acid-reducing medications.
GERD symptoms can result occasionally result from mechanical problems related to either a mechanical problem within the Sleeve or a pre-existing hiatal hernia. This is a common condition (affects almost 20% of the general population) where the union between the stomach and the esophagus happens above the diaphragm (an umbrella shaped muscle that separates the chest from the abdominal cavity). The esophagus or food pipe passes through a hole ("hiatus") in the back portion of this muscle to join the stomach normally instead of below the diaphragm.
While most patients with a hiatal hernia do not have symptoms, in some, especially after they have had significant weight loss, it could potentially be the cause of GERD/ GERD related symptoms. This can be addressed by laparoscopic hiatal hernia repair.
As mentioned earlier, the VSG remnant stomach tube - has a natural angulation about midway between the lower esophageal sphincter (LES) (or the upper stomach valve at the bottom of the esophagu) and the pylorus (lower stomach valve). This is the watershed zone (called the "incissura" of the stomach) between the more easily distensible upper portion of the stomach tube ( the "fundus" and "body" of the original stomach) and the less distensile lower portion of the stomach ( the "antrum"). The stomach tube is naturally bent at this spot. This is what creates a natural angulation within the stomach tube which typically does not cause a problem. Rarely, this may be the site of a fixed obstruction or stricture which may need to be addressed by a UGI endoscopy with endoscopic balloon dilation. Lack of response to these conservative methods may warrant a revision to a Roux-en-y (RNY) gastric bypass. Traditionally most of these are Proximal RNY gastric bypasses. This typically involves dividing the stomach tube about a couple of inches below the gastroesophageal (GE) junction or LES(where the esophagus joins the stomach) to create a small stomach pouch. The upper intestine (called the jejunum) is then divided about a foot from where it originates (thereby creating a short BPL). The bottom end of the divided intestine (called the Roux limb) is then connected to the stomach pouch. The short BPL is then attached to this Roux limb about 5 feet downstream to create a long (usually not measured) CC. This operation is usually associated with a ~50% medium-term EWL and has some risk for weight regain (as is typical of all gastric restrictive surgeries)
Malabsorptive RNY GBP (MGBP)
Under certain circumstances, depending on the patient's disease burden (e.g., h/o Super Obesity i.e., initial BMI > 50 or Super-Super Obesity i.e., initial BMI >60) and associated co-morbidities ( e.g., diabetes) we could create a malabsorptive RNY GBP (MGBP) with a long BPL, a ~10 ft AL and short ( usually 5-7 ft) CC. These operations (as with all malabsorptive operations) are associated with a 70-75% EWL with a lower risk for weight regain.
As a general rule, all revisions do carry a higher risk for complications such as leaks, infections, bleeding and medical problems such as clot formation in the legs ( deep vein thrombosis) or lungs ( pulmonary embolism). It is important to therefore choose a bariatric surgical practice that has established a good track record in performing complex revisions.
Thorough evaluation and appropriate revision surgery can address these issues effectively and restore health and quality of life.
ABOUT THE AUTHORMyur S. Srikanth, MD, FACS, is a Board certified bariatric surgeon and has been performing bariatric surgery exclusively since 2000. He has performed more than 3,500 weight loss surgeries, with more than 2,500 of those done laparoscopically. He performs every operation that is currently available to treat obesity at The Center for Weight Loss Surgery.
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