Roux-en-Y Gastric Bypass

The Roux-en-Y gastric bypass (RYGBP) is the most commonly performed WLS in the world today. This operation has a long track record of success in the management of morbid obesity around the world and in the United States. The results of this procedure are the standards by which all other procedures are compared. Before 1995, the majority of these procedures were performed through a large abdominal incision. Currently, the laparoscopic approach has become more prevalent as a result of patients’ demand for lesser invasive procedures and advances in surgical techniques. Much like the Lap Band® procedure, the gastric bypass is designed to limit meal intake by creating a sensation of fullness with smaller food volumes. In addition, the majority of the stomach and several feet of small intestine are bypassed and no longer come in contact with ingested food. This combination of restricted caloric intake and a moderate malabsorptive component give rise to a hybrid procedure that has profound beneficial effects.

How it Works

A key feature of this operation not seen in with the Lap Band® or duodenal switch procedures is appetite suppression. Hunger and food cravings are virtually eliminated for up to 6 months after surgery in most patients. Weight loss is fairly dramatic for the first year and tapers off over the following 6 months. By 18 months, a weight loss plateau at a level above ideal body weight and an average 65 to 70% of excess body weight (EBW) is lost.

Even more dramatic than weight loss, type 2 diabetes, characterized by insulin resistance and the ever-increasing need for greater doses of insulin injections is either cured or dramatically improved in 86% of diabetic patients. This radical reversal of diabetes often occurs within one month of the operation, long before significant weight loss has occurred.

The mechanism by which the RYGBP works is complex. After surgery, patients often experience marked changes in their behavior. Most patients have a reduction in hunger and feel full sooner after eating. Patients often state that they enjoy healthy foods and lose many of their improper food cravings. Rarely do people feel deprived of food. These complex behavioral changes are partially due to alterations in several hormones (ghrelin, GIP, GLP, PYY) and neural signals produced in the GI tract that communicate with the hunger centers in the brain. Another mechanism for weight loss after the RYGBP is referred to as the dumping syndrome. Dumping may result in lightheadedness, flushing, heart palpitations, diarrhea and other symptoms early (within 10 to 30 minutes) after eating sweets or foods with a high concentration of sugar. Some people remain extremely sensitive to sweets for the rest of their lives; most patients lose some or all of their sweets sensitivity over time.
 

Laparoscopic Roux-en-Y Gastric Bypass

Clinical studies have demonstrated that laparoscopic RYGBP is a safe and effective alternative to open RYGBP for the treatment of morbid obesity. Dr. Higa and colleagues reported the largest laparoscopic RYGBP experience with 1,500 operations. There have been three prospective, randomized trials comparing the outcomes of laparoscopic vs. open RYGBP. Nguyen and colleagues reported the largest trial in 2001. In 2004, a group from Murcia, Spain published their results. Long-term weight loss after laparoscopic and open RYGBP should not differ, as the primary differences between the two techniques is largely in the method of access and not the gastrointestinal reconstruction.

Despite the advantages of the laparoscopic approach, open bariatric surgery still plays a prominent role in management of morbidly obese patients. Relative contraindications for laparoscopic bariatric surgery include patients with extremely high body mass index, patients with multiple previous upper abdominal surgeries, and patients with prior bariatric surgery. Another limitation of the laparoscopic approach is the steep learning curve of this technically challenging procedure for the surgeon, so it is not an operation for the surgeon who has not been trained specifically in this technique.

Benefits of Surgery

As important as it is for patients to understand the gravity of weight loss surgery, the overall benefits must also be carefully evaluated. Those of us in the field of bariatric surgery observe the incredible life changing events which occur routinely in our patients. It is extremely gratifying to be able to provide surgical therapy, which so greatly impacts our patients in such a positive way. It is truly an honorable and rewarding profession.

While this personal reflection may appear romanticized, there is clearly an emerging volume of credible scientific evidence that weight loss surgery is not only effective in producing lasting weight loss, but also significantly reducing obesity-related illness. When one evaluates the alternatives to surgery in the morbidly obese population, there is no comparison.

Bearing in mind that the morbidly obese population is by definition at high risk for serious, life-threatening diseases, any therapy that creates significant weight loss must also diminish associated comorbidities. Such benefits have been repeatedly documented in several thorough clinical investigations.

In the year 2000, an interesting study was published in the Annuls of Surgery depicting extremely high cure rates for associated comorbidities in the morbidly obese who underwent Roux-en-Y gastric bypass1. The results illustrated in the table below are a list of the diseases commonly associated with patients who are morbidly obese.

 Adapted from  Ann Surg. 2000 October; 232(4): 515–529.

This and other retrospective studies demonstrate high cure rates for obesity-related illnesses and although not all reports established such significant positive changes, most of the published literature of the past 20 years confirms with the dramatic improvement in obesity-related diseases after Roux-en-Y gastric bypass.

Dr. Christou and his team from McGill University in Montreal, Canada compared their results of outcomes in thousands of patients who either underwent weight loss surgery or diet therapy without surgery2. After five years, the surgery patients enjoyed an 89% decreased risk of dying over the group treated with diet therapy only. Not only did they also reduce their overall health care costs by 50%, they also benefited from a 400% reduction in cancer incidence and 50% reduction in hospitalizations.

Dr. Buchwald published the most convincing evidence touting the overall safety and efficacy of weight loss surgery in 2004 in the Journal of the American Medical Association3. In this article, the outcomes of over 22,000 patients who underwent weight loss surgery in the United States in highly reputable medical facilities were investigated. Careful analysis of the results demonstrated low complications and death rates in addition to dramatic and lasting weight loss and most importantly, the resolution of comorbidities. Dr. Buchwald’s paper highlights the phenomenally high cure rates for diabetes, hypertension, sleep apnea, and hyperlipidemia. The results of this careful study illustrate what most of us who manage patients after weight loss surgery already know; bariatric surgery produces reliable and sustained weight loss along with striking resolution of most obesity-related diseases

1. Schauer P R et al. Ann Surg. 2000 October; 232(4): 515–529.
2, Christou NV; MacLean LD McGill,. Adv Surg. 2005; 39:165-79
3. Buchwald et al. JAMA Oct 2004; 292(14); 1724-37.
 

Weight Loss

The gold standard in bariatric surgery in the 21st century is still the RYGBP. Undoubtedly the most studied and time-tested procedure in the last 50 years, the RYGBP is the most reliable weight loss operation currently available. The restrictive nature of the operation is combined with an additional feature lacking in the Lap Band® procedure or the outdated vertical banded gastroplasty (VBG). Cessation of huger and food cravings is a distinct advantage of the RYGBP over other operations. Two features of this operation contribute to this beneficial effect, separation of the gastric pouch from the remaining stomach and diversion of food away from the duodenum.

Creating a separate gastric pouch surgically disconnects neural pathways from the brain to portions of the stomach, thereby minimizing the conscious awareness of hunger. These nerve fibers slowly regenerate over a 6 to 8 month period, so the effect does subside over time.

By creating a bypass of the gastric pouch to the small intestine, the undigested meal is never allowed to contact the lining of the remaining stomach and duodenum. For reasons not fully understood, this diversion of undigested food away from the duodenum creates a dramatic reversal of insulin resistance, the primary feature of type II diabetes. A degree of malabsorption is also provided by this step that limits, to a degree, the amount of small intestine allowed to come in contact with and absorb nutrients.

While the length of the bypassed segment of stomach and intestine remain constant, the length of the Roux limb varies based on the BMI of the patient. In patients whose BMI is < 50, the length of the Roux limb will be maintained at 100cm or about 3 feet. For patients whose BMI is > 50, the Roux limb will be extended to a length of 150cm or 4.5 feet. Adding length to the Roux limb actually decreases the length of the small intestine allowed to absorb nutrients, thereby increasing the malabsorptive component of this procedure. A greater degree of malabsorption is added to patients whose BMI is >50 (“super morbid obesity”) because it leads to greater weight loss.
 

Longer Roux limb leads to greater weight loss.

Long-term studies of weight loss with RYGBP concur with a significant drop in weight for the initial 6 months after surgery. From this point, weight loss tapers off slowly over the next 6 to 12 months. At 18 to 24 months after RYGBP, weight loss plateaus and in approximately 10% of people, weight gain may occur. This is the direct result of unhealthy eating habits that creep back such as increasing starches, fats and ‘soft’ foods such as potatoes, pastas, and rice.

The above graph describes the weight loss in open gastric bypass patients (OGBP) to laparoscopic gastric bypass (LGBP). The weight loss curves are nearly identical. Note that after 18 months, the weight loss stabilizes. Open gastric bypass patients tend to have larger BMIs whereas LGBP patients tent to have lower BMIs. This graph demonstrates that there is no difference in weight loss after RYGBP whether the procedure is performed as an open procedure or via laparoscopic techniques.

In this study, the graph above suggests slight weight loss after 18 months, however there appears to be modest weight gain between months 24 to 30. Note the similarity in the weight loss curve to the prior study.

Advantages

• The average excess weight loss after the Roux-en-Y procedure is generally higher in a compliant patient than with purely restrictive procedures (Lap Band® procedure).
• One year after surgery, weight loss can average 77% of excess body weight.
• Studies show that after 10 to 14 years, some patients have maintained 50-60% of excess body weight loss.
• A 2000 study of 500 patients showed that 96% of certain associated health conditions studied (back pain, sleep apnea, high blood pressure, diabetes and depression) were improved or resolved.

Risks

• Because the duodenum is bypassed, poor absorption of iron and calcium can result in the lowering of total body iron and a predisposition to iron deficiency anemia. This is a particular concern for patients who experience chronic blood loss during excessive menstrual flow or bleeding hemorrhoids. Women, already at risk for osteoporosis that can occur after menopause, should be aware of the potential for heightened bone calcium loss.
• Bypassing the duodenum has caused metabolic bone disease in some patients, resulting in bone pain, loss of height, humped back and fractures of the ribs and hipbones. All of the deficiencies mentioned above, however, can be managed through proper diet and vitamin supplements.
• A chronic anemia due to Vitamin B12 deficiency may occur. The problem can usually be managed with Vitamin B12 pills or injections.
• A condition known as "dumping syndrome" can occur as the result of rapid emptying of stomach contents into the small intestine. This is sometimes triggered when too much sugar or large amounts of food are consumed. While generally not considered to be a serious risk to your health, the results can be extremely unpleasant and can include nausea, weakness, sweating, faintness and, on occasion, diarrhea after eating. Some patients are unable to eat any form of sweets after surgery. Dumping is considered by many to be an advantage because it helps avoid unhealthy eating.
• In some cases, the effectiveness of the procedure may be reduced if the stomach pouch is stretched and/or if it is initially left larger than 15-30cc.
• The bypassed portion of the stomach, duodenum and segments of the small intestine cannot be easily visualized using X-ray or endoscopy if problems such as ulcers, bleeding or malignancy should occur.
 

Complications of Surgery

As with any surgery, there are immediate and long-term complications and risks. Two complications pose the greatest risk after RYGBP surgery, staple line leak and pulmonary embolism (blood clot to the lung). Remember, these two complications usually occur within the first 2 to 3 weeks after surgery, so it is unlikely to develop either of these complications after 1 to 2 months after surgery.

If staple line leak and pulmonary embolism are suspected, X-ray studies such as CT scans and fluoroscopic exams are used to confirm both complications. Even the most up-to-date CT scanners, however, have weight limits up to 450 lbs. Both CT scanners and fluoroscopy tables at Baptist hospital have 450 lb. weight limits. This means that if you weight more than 450 lbs., you must understand that should your physician suspect a staple line leak or a pulmonary embolism after surgery, there is no radiological method available to confirm or rule out your diagnosis. In these cases and in others, your physician will likely treat your condition empirically, that is without actually confirming the diagnosis, as both these conditions can be lethal if left untreated. The treatment for a staple line leak could include emergent re-exploration in the operating room to close the leak and drain the area. Pulmonary emboli are managed by administering blood thinning medications as Heparin® or Warfarin that inhibit further clotting. I will speak with you further about the benefits and risks if you wish. Possible risks can include, but are not limited to:

Leaks from staple lines
Deep vein thrombosis and pulmonary embolism (blood clot to lung)
Bleeding*
Complications due to anesthesia and medications
Infections
Stricture
Marginal ulcers
Bowel obstruction
Nutrient deficiency
Death

* To control operative bleeding, removal of the spleen may be necessary.

Staple line leaks can occur wherever the GI tract is joined together either at the gastric pouch connection or the small bowel connection. Normally, if a leak occurs, it is within 3 to 5 days after surgery. Most leaks occur after the patient has already begun ingesting liquids in the hospital or at home.

Leaks are prevented at surgery by assuring proper visualization, firing and maintenance of stapling devices. All pouches are routinely checked for leak before the operation is terminated by injecting the pouch with methylene blue dye and inspecting the staple line for dye leakage. After the dye test, air is injected into the pouch as it placed under water to inspect for air bubbles at the staple line. If a leak is identified by either test, it is promptly repaired with suture and both tests are repeated until there is no evidence of leak. The operation is not complete until the pouch is assured to be both air and watertight.

After 4 to 5 days from surgery, the healing processes have replaced the staple lines by laying down scar and healing tissue. Once this healing process is complete, there is virtually no risk of a leak. Any process that inhibits the healing process, therefore, increases the potential for a leak.

Nicotine and other tobacco products as well as chronic steroid use promote poor wound healing. Both of these conditions are contraindications for weight loss surgery and will eliminate patients as candidates for surgery. Patients must abstain from ingesting or smoking tobacco for 30 days before surgery. Lab samples are tested before surgery to check compliance.

The typical signs of a leak are

• Worsening chest or abdominal pain
• Fever
• Shortness of breath
• Rapid pulse
• Nausea & vomiting
• Clammy skin

If these signs occur in the hospital, the patient will be taken immediately to the Radiology Department to undergo testing. An upper GI will often demonstrate the leak quickly and allow rapid treatment that may require laparoscopic or open surgery to repair the leak and add drains. A CT scan of the chest may be ordered to rule out a blood clot to the lung as many symptoms overlap. Sometimes the leak may not develop until later in the course of recovery. If the leak appears to be contained, that is, it is not flowing freely into the abdomen, then simple drainage of the fluid collection may be all that is necessary. A leak can be disastrous if it remains unrecognized or untreated. It is vitally important that patients seek out “Centers of Excellence” for their surgery, as these hospitals and surgeons are prepared for and equipped to manage all situations 24 hours a day.

Pulmonary Embolism or blood clot that travels to the lung is extremely rare occurring <1% of cases. These are blood clots that form in the deep veins of the calves during or immediately after surgery. They can occur after any form of surgery, after prolonged sitting or in women who are on hormone therapy. When the blood clots form in the vein of the leg, they may adhere to the wall of the vein or they may dislodge. A dislodged blood clot will travel with the blood flow back to the heart. The heart then pumps returning venous blood to the lungs where the clot will become lodged. A large clot will essentially diminish the lungs capacity to oxygenate blood and within 2 to 3 minutes patients can succumb. Pulmonary blood clots are serious but rare. It is impossible to predict which patients are at risk, therefore all patients are treated as if they are at risk.

Prior to surgery, patients will receive a form of Heparin® in the holding area to thin the blood and make it less prone to clot. In addition, compression hose and pneumatic pumps are applied prior to the start of the procedure. Blood thinner therapy and the calf compression therapy will be continued throughout the hospital course and early ambulation will begin on the night of surgery. Patients are encouraged to walk four times a day in the hospital and at home. Walking promotes blood flow in the legs and decreases the risk of clot formation.

Pulmonary emboli are suspected when a patient becomes short of breath and the blood oxygen level drops suddenly. A CT scan of the chest may confirm or rule out the possibility of a blood clot in the major vein feeding the lungs. The treatment is immediate transfer to an ICU, respiratory support if needed and intravenous high-dose blood thinner to prevent further clots and initiate clot retraction. The weight limit for the CT scanner at Baptist Hospital is 450 lbs. Patients who weight more than 450 lbs will be too heavy for the limits of the scanner. Patients who weigh more than 450 lbs must understand prior to surgery that their physicians may be at a disadvantage because of this limitation. In these circumstances, patients are treated empirically; meaning therapy may be instituted without benefit of confirming tests.

Bleeding is a risk of any intraabdominal surgery. The risk of bleeding after RYGBP is approximately 3%. Most bleeding stops spontaneously avoiding the need for transfusion or return to the operating room. Occasionally, blood transfusions may be required, however this is unlikely. Bleeding can occur at the various staple lines or form blood vessles inside the abdomen.

Complications due to anesthesia and medications are generally caused by reactions to the anesthetic agents. Drowsiness, nausea and sore throat are common effects from the anesthetic event. The induction of general anesthesia may precipitate heart and airway problems that already exist. Morbidly obese patients can have undiagnosed heart disease or sleep apnea that manifests during or after the procedure. Often these patients require overnight ICU observation and may remain on the ventilator for additional hours or days until it is safe to allow them to breathe on their own.

Infections in laparoscopic incisions are rare and inconsequential. Wound infections in the obese patient with open surgery, however can be a serious issue unless treated aggressively. All patients receive intravenous antibiotics before and after surgery to decrease the incidence of infections. Infections on the inside of the abdomen are much more serious. An abscess may require operative intervention and prolonged hospital stay. Most Intraabdominal infections are due to contamination of the peritoneal cavity from gut bacteria.

Strictures are areas of scarring that occur at the junction of the gastric pouch to the small intestine. Strictures occur 4 to 8 weeks after surgery and are the result of contracture of scar tissue that forms at the staple line in 7-10%. It is desirable to have a modicum of narrowing at this location to maintain satiety after meals. However, if the opening admits less than the diameter of a pencil, solids will be regurgitated and liquids may be the only means of intake. Fortunately, strictures are easily managed by endoscopic dilation with a soft balloon. Often a single dilatation is all that is required.

Stricture at pouch opening.

Marginal ulcers are ulcerations that occur just below the pouch to small intestine junction. They cause pain, nausea, and may lead to a stricture if the ulcer is chronic. Smokers are at highest risk for the development of marginal ulcers which can occur in about 4% of cases. Many studies document the leading cause of ulceration in those who begin smoking after their bypass. These ulcers may be difficult to treat even with routine anti-ulcer medications. Ulcers can erode into underlying blood vessels and cause GI tract bleeding that may require surgical correction. Prevention is the best medicine. Gastric bypass patients should avoid certain medications that can cause ulcers as Ibuprofen (Advil®), Nuprin® or Naprosyn®.

Bowel obstruction after weight loss surgery may be from several different sources. Although it arises in 2.5% of cases, the most common cause of bowel obstruction is from internal hernias where a portion of the small intestine can twist and wrap around or through a space created by the new surgical anatomy. These potential spaces are closed at the time of surgery, however with laparoscopic surgery, intraabdominal scarring is sparse leaving the small intestine more mobile. Even small openings between layers of tissue may allow enough room for the bowel to worm its way and create obstruction. The diagnosis of an internal hernia may be difficult as internal hernias may be intermittent and undetectable on CT scanning. The treatment is laparoscopic exploration and closure of the defect with permanent suture.

Internal hernia after RYGBP.
CT scan of internal hernia, trapped bowel in white.
 

Nutrient deficiency is the Achilles heel of the RYGBP. It has been estimated that up to 30% of patients may be iron or calcium deficient after RYGBP. Patients who are considering this operation must understand they are mandated to take supplemental vitamins, calcium and iron every day for life. The duodenum is the portion of the small intestine where calcium, iron and B12 are preferentially absorbed. Because the duodenum is no longer in the stream of food flow, RYGBP patients become susceptible to vitamin and nutrient deficiencies that lead to anemia, osteoporosis and lethargy. Hence, routine blood work is required on an annual basis to assess vitamin and nutrient levels. Long-term follow up is mandatory as most patients become less compliant with medications after surgery; as their co morbid conditions diminish, they become accustomed to taking fewer and fewer medications.

Nutrient absorption.

The specific types of nutrients and their doses must also be noted. Calcium citrate is recommended rather than other forms of calcium because of better absorption. Iron absorption is improved when taken with citric acid (orange juice) and diminished when taken with calcium so the two pills must be taken at different times of the day. Vitamin B12 is poorly absorbed in RYGBP patients requiring either oral dissolvable tablets or monthly injections. Folate and Vitamin D levels need attention as well. The long-term effects of iron and calcium deficiencies are insidious and debilitating if left untreated.

Protein intake is stressed to all surgical weight loss patients regardless of their procedure. RYGBP patients tend to loose weight rapidly and can loose muscle mass in great proportions. Protein ingestion and exercise will minimize muscle wasting and hair loss that normally arises 6 to 8 after surgery. This leads to the recommendation of 60 to 80 grams of daily protein ingestion. Most dieticians recommend RYGBP patients fill up on the protein in their meals first to assure adequate intake.

Death after RYGBP was the subject of serious study in a meta-analysis published in JAMA (Journal of the American Medical Association) in 2004. This analysis compared outcomes in over 22,000 patients who underwent weight loss surgery in reputable American university affiliated programs. The RYGBP mortality was 0.5% compared to Lap Band® at 0.1% and duodenal switch at 1.1%. According to the American Society for Bariatric Surgery 2004 Consensus Statement, the operative mortality (death) associated with Roux-en-Y gastric bypass in the hands of a skilled surgeon is roughly 0.5 percent.
 

Relative mortality rates for other commonly performed operations in the United States may help shed some perspective on the issue of operative mortality.

Diet After Surgery

After RYGBP, the newly created gastric pouch is smaller than a chicken egg. The walls of the pouch are swollen from the manipulation of surgery and its capacity is severely limited for the first 2 weeks after surgery. Liquids are all that are acceptable for the first 1 to 2 weeks after surgery. It may be all you can do to ingest water. We recommend non-carbonated, low calorie liquids only for the first 2 weeks. Liquids are the most important priority. Because you are no longer able to chug, it is important to carry a jug or measured container with you all the time. This ensures your ability to take in at least 32 oz. of water a day.

After 2 weeks, the pouch walls are stiff and inelastic. Patients often begin noticing odd sensations and nauseating smells. Some patients will be unable to tolerate perfumes or sweet odors. They may notice that odors that were once pleasant become nauseating or intolerable. This changes over time, however, it can be quite upsetting initially. It may greatly affect how and what you eat. A simple odor may create an unexpected avoidance of that particular food forever. Over time, your pouch will soften and begin to comply with the meal. It will then be possible to actually begin meals with more consistency.

Recommended Diet Schedule After Gastric Bypass
Weeks 1 and 2 Liquids - non-carbonated, low calorie
Weeks 3 to 6 Puréed foods – use a blender
Week 7 Soft foods
Week 8 ‘Regular’ diet – small portions, chew, chew, chew.

From the 3rd to the 6th week after surgery, pureed foods are recommended. A pureed diet requires a blender. Puréed food has the consistency of a thick liquid, so if you desire spaghetti, put it in the blender and give it a try. If you cheat, you may see your meal again. This is also the time to begin learning about the protein content of specific food items. Our goal is to eventually increase the protein to a daily intake of at least 80 grams. 80 grams of protein a day is likely more protein than most people are used to eating. Liquid protein drinks and powders that can be mixed in a liquid are often an acceptable way to achieve daily protein requirements.

At 2 weeks, you will start taking your multivitamin and Pepcid®. After 4 weeks, you should begin taking your iron and calcium. Remember to take the calcium citrate at different times as the iron. (Calcium diminishes iron absorption.)

After 6 weeks, soft foods are on the menu for week 7. Start off with gentle items like mashed potatoes, yogurt, grits, oatmeal, or well-cooked pastas. Once you have mastered these, or at least figured out what will work for you, then at about the 8th week, you are ready for real food. Avoid steak, hamburger, pork and highly spicy foods at first. Chew your foods carefully and slow down your pace around mealtime.