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Benefits and Risks of Surgical Treatment of Serious Obesity

For someone who is interested in the ideal of surgery, to get control of serious obesity, the key question is the benefits to be gained from surgery, versus the risks that one must go through, in order to have an operation. Usually, the risks are taken right away, when the surgery is performed, and the benefits take a while to pay you back, in the form of improved health, reduced long-term risk of illness, and enhancement of your lifestyle.

It’s a personal decision, as well as a medical one. Our doctors can teach you about the risks, and help you measure the likelihood of benefits, and will tell you frankly, if they are out of balance for you. Still, the final decision is up to you. To make it intelligently, you need to know all about the risks, and the benefits, of the operation.

Risks and Complications of Surgery

The risk of a weight control operation is mainly the risk of having any abdominal operation. It is the act of having an operation, not the particular operation which is done, that causes most of the risk. Severely obese persons are well known to be at a disadvantage, when having surgery, and their risks are higher than they would be at a normal body weight.

The risk of surgery comes mainly from its complications: things can go out of control, causing serious problems, often without any good reason. Having an abdominal operation places a lot of stress on the body. It creates an open wound, which can bleed or fail to heal, and it opens the door to potential infection. The emergency reaction of the body to injury can itself by harmful, when it leads to reactions such as increased clotting of blood, which can cause a fatal pulmonary embolism. Let’s look at the risks in detail.

Lung Problems

This condition is a partial collapse of a part of the lung, caused by lack of motion of the chest wall. Normally, your lung is filled with tiny air spaces, like the tiny spaces in a loaf of bread, only much smaller. Picture what happens, when you take a loaf of bread and sit on it, and you get an idea of how the lung collapses. The best treatment is to prevent it, by deep breathing and lung exercises. We teach you these before surgery, and encourage you to do them again and again, after the operation. We also have special treatments, and even pulmonary medicine specialist consultants, to help you and your lungs recover, if atelectasis occurs. Atelectasis can cause a fever after surgery, and can also lead to developing pneumonia.

Pneumonia is an infection in the lungs, and after surgery it can be especially serious, because the infecting organisms often come from the gastrointestinal tract, and they can be very destructive. We prevent pneumonia by clearing out the GI tract ahead of surgery, by using antibiotics at the time of operation, and by generally using good anesthesia and respiratory treatment, to prevent atelectasis.

This problem affects the lungs and the heart, but it usually starts in the legs, with the formation of blood clots. Although these can occur at any time, and are more likely in overweight patients, they are especially likely at the time of and soon after surgery, because people who have an operation don’t like to move around, or exercise their legs. The blood becomes stagnant and clots in the leg veins, and if a clot breaks off and floats through the veins to the lungs, it is called a pulmonary embolism. The blood clot blocks the arteries in the lungs, and can cause a part of the lung to lose its circulation and die – a pulmonary infarction. If the circulation to a large part of the lung is affected, the heart is placed under a lot of strain, and it may fail suddenly, which can be fatal.

We prevent a pulmonary embolism, first, by thinning the blood with heparin, which makes it less likely to clot. We prescribe elastic stockings, to compress the legs and keep the blood flowing faster in the veins. We try to keep the operation short, by operating efficiently (not hurriedly), and by getting patients up to walk as soon as possible.


An abscess is a collection of infected fluid, or pus, which occurs somewhere in the body. After an abdominal operation, a pocket of fluid may develop, and if any bacteria are present, they may infect it and create an abscess. The treatment of any abscess is to drain away the infected fluid, and kill the bacteria with antibiotics.

We prevent abscesses by trying to avoid any collections of fluid or blood in the abdomen, at the time of surgery, and by placing a drain if one might possibly occur. If an undrained abscess develops, we now have very skillful specialists, called interventional radiologists, who often can achieve drainage, and resolve the problem, without a need for an operation to drain it.

A wound infection is a type of abscess, and is treated the same way, by drainage. Seriously obese persons have a very deep layer of fat under the skin, and the usual methods which surgeons use for treating infection there do not work very well in the obese. We have developed special methods, and using these, most such infections are relatively easy to treat, although they can cause discomfort and inconvenience for a while.

Urine flow is altered after surgery, and patients also have trouble straining down, to void. Use of a tube, or catheter, may be necessary to drain the bladder. In a rare case, this can lead to infection of the bladder. Usually such an infection can be readily eradicated with antibiotic treatment, without any additional hospital stay.


We use heparin to prevent blood clotting and pulmonary embolism. At the same time, if blood does not clot at all, bleeding will occur, when surgery is performed. We have to try to find a middle ground, but because the sensitivity of different individuals may vary, delayed bleeding may occur after surgery in some persons. We observe closely for this, and can stop the heparin if bleeding gets to be a bigger risk.

When surgery is performed, blood vessels must be cut. We handle these by tying them with a piece of thread, called a ligature, or by using a device called an electrocautery, which coagulates the blood, and the end of the blood vessel. Sometimes, a blood vessel may escape, and then begin to bleed again several hours later. This can cause a hemorrhage, either inside the abdomen, or at the skin level.

Hemorrhage must be stopped. We have several strategies for this, but in some cases, a return to the operating room may be needed. This is a rare event.

When blood loss occurs, that tend to make the pulse and blood pressure unstable, a transfusion may be needed. The blood bank has very high quality standards, and the blood is quite safe, but there is still a possibility of getting hepatitis, and a very small risk of receiving the AIDS virus (about 1 in 500,000), from a transfusion. These risks can be reduced, by donating your own blood and having it saved for your surgery – a procedure called autologous donation. This costs quite a lot (about $125 per pint), and we feel it is probably not economically sound, since the likelihood of needing the blood is quite low.

We also have performed surgery successfully on many occasions under the Bloodless Surgery Program, when patients decline to receive blood or blood products for religious reasons. We will honor a commitment to avoid transfusion, on your instructions.

Bowel Obstruction

After any abdominal operation, scars called adhesions will form in the abdomen. These look like strands of latex, or sometimes like a piece of fibrous cord, and can snag a piece of bowel – just like your garden hose can wrap itself around the smallest bump, when you pull on it. Sometimes, even many years after the original operation, the bowel becomes kinked around an adhesion, becomes obstructed, and nothing can get through. This must be relieved, especially before the bowel loses its blood supply and dies, which can make the bad situation even worse. Usually an emergency operation is necessary.

Occasionally, a bowel obstruction can occur within a few days after surgery. In this case, the adhesions are much softer, and will often come apart on their own, if conditions are made right.

Leakage of Bowel Connections

When the surgeon fastens bowel to bowel, or bowel to stomach, the connection is called an anastamosis. If it does not form a complete seal, and leakage of fluid from within the bowel occurs, it is called an anastamotic leak. Fluid from the GI tract, containing at least some bacteria, leaks out into the abdomen where it doesn’t belong, and causes a serious infection, accompanied by much swelling, a rapid pulse rate, and sometimes, formation of an abscess. This is always a very serious complication, and its diagnosis and treatment are made much more difficult by severe obesity.

Conventional wisdom indicates that an immediate operation is required, to seal the leak and drain away the infection. Our experience has taught us that, more than half the time, such an operation may cause more harm than good, and that it can and should be avoided. Drainage may already be present, and if not, it can often be obtained by the interventional radiologist, without surgery. When this is possible, the insult of surgery, and the spreading of infection through the rest of the abdomen, can be avoided. 

Anastamotic leak almost always causes some increase in hospitalization, and increased discomfort from the drain, and the need for repeated X-rays.

Obstruction of the Stomach Outlet

In performing the Gastric Bypass, when the stomach is connected to the bowel, to opening is deliberately made small, about inch in diameter, to slow the flow of food out of the small stomach pouch. All healing occurs by scar formation, and scars always have a tendency to contract. This may cause the opening between stomach and bowel to become too small, so that no food can get through. This causes repeated vomiting, and must be corrected.

This type of problem used to occur in about up to 10% of cases, and many surgeons continue to be troubled by this complication. The treatment is quite simple, and can be done as an outpatient procedure. However, as we have worked to refine the Gastric Bypass, we have noticed that the incidence of this problem has declined, almost to the vanishing point, less than 0.5% of both open and laparoscopic operations. We believe this may be due to improved anatomy, and improved blood supply to the affected bowel, and we recently reported our findings to an international meeting of bariatric surgeons. 

Chronic Nutritional Problems

Nutritional problems are quite rare after the Gastric Bypass, and are quite readily avoided by use of the proper vitamin and mineral supplements, and by eating a healthy diet. One of our most important objectives during our long follow-up is teaching food values, and the content of a healthy eating regimen. A remarkable effect of the Gastric Bypass is the progressive change in attitudes toward eating. Patients begin to eat to live - they no longer live to eat.

Protein is the essential stuff, of which our muscles, organs, heart and brain are all constructed. Our bodies require a constant supply of protein building materials, to repair and replace tissues which become worn out or damaged. The Gastric Bypass and the Gastric Banding both reduce the capacity of the stomach to a very small volume, so that protein-containing foods must be carefully eaten with each meal, to be sure that the body gets enough to maintain itself. If the first half of each meal is taken as protein-containing foods, deficiency is very unlikely to occur. We do not advise the use of protein supplements or beverages.

Conventional nutritional teaching has been that vitamins are contained in adequate amounts in a well-balanced diet, and supplements should not be required, provided that one eats a well-balanced diet. After weight-control surgery, the diet is initially much less than enough to supply complete nutrition – that’s why you lose weight. In order to have any chance of getting enough vitamins, a high potency multivitamin supplement must be taken daily. We think its safest to do this for the rest of your life, after this type of surgery.

In addition, we have seen a few persons develop deficiency of Vitamin B-12, even when taking a multi-vitamin supplement. B-12 is absorbed in the stomach and duodenum, which are largely bypassed with this surgery. Simple use of a sub-lingual (under the tongue) tablet of B-12, once a week, maintains very adequate vitamin levels, and prevents deficiency, which can develop without warning, until it becomes very dangerous.

Our recommended multivitamin preparation contains mineral supplements in generous amounts. We also recommend daily use of calcium, and many patients, particularly women, will require a special iron supplement, to maintain adequate iron stores and prevent anemia of iron deficiency.

The total cost of all the needed supplements is about $20 per month.

Side-Effects of the Gastric Bypass, and the Gastric Banding

Side-effects occur with any operation. Although they are less serious than complications, they may be permanent, and may require a change in lifestyle, to avoid continuing discomfort.

After gastric restriction, if one gets a full feeling, and continues to eat, chances are an episode of vomiting will result. Most patients have this happen several times, and most quickly learn to follow instructions to eat slowly, chew food well, and avoid that last bite when fullness occurs. Typically, with the gastric Bypass, a profound feeling of satisfaction follows the fullness within a few minutes, and makes further eating a matter of indifference. The Gastric Banding does not produce this sense of satisfaction as quickly, or as intensely.

During the first few days to weeks, another kind of nausea may follow the gastric bypass. This results from delayed function of the Y-limb, and spontaneously resolves with time.  If a patient experiences this type of nausea, we feel it is very important to suppress it with medications, called anti-emetics.  Persistent vomiting can lead to dehydration and electrolyte imbalance, and can cause vitamin deficiencies to occur, since one cannot take required supplements.  

After either the gastric bypass, or the gastric banding, red meats are not well tolerated, and may cause vomiting. This is purely a mechanical effect – your stomach cannot tell steak from chicken, except that steak is much harder to break down so that it will fit through the small stomach outlet. If the outlet gets plugged, vomiting will result. We advise patients to avoid red meats until their stomach is functioning very well, usually after at least 3 – 4 months.

Refined sugars and candy consist of many small molecules, which tend to draw fluid into the intestine. After the gastric bypass (not after the gastric banding), a condition called "dumping syndrome" may occur, when sugar is taken on an empty stomach, passes rapidly through the stomach into the intestine, and draws a large amount of fluid into the bowel. The physiology is complicated, but the result is a condition like shock: one turns ghostly pale, breaks out in a profuse sweat, feels butterflies in the stomach, a rapid pulse, and a feeling of prostration. Nausea and vomiting, cramps and diarrhea may follow. Most people who have this reaction never try to sneak another candy bar – and we think that’s not such a bad effect, if you’re trying to lose weight.

The problem of dumping is avoided by avoiding sweets, candies, and fruit juices on an empty stomach. Certain dressings, barbecue sauce and mayonnaise may also cause problems, and need to be avoided.

To digest milk sugar (lactose), our bodies need and enzyme called lactase, which is often in short supply in the lower small intestine. After gastric bypass (not after gastric banding), milk and milk products may not be fully digested. Farther downstream, they are fermented by bacteria, and this causes gas, cramps and diarrhea.

Milk can be treated, to make it tolerable. In the big picture, it’s probably better to avoid it. Many prepared foods (those that come in a box, or frozen entrees) contain milk sugar as an additive. It is important to learn to be a label-reader, or to avoid packaged foods, and especially junk food.

After restrictive surgery, the amount of food consumed is greatly reduced, and the quantity of roughage consumed may be much smaller. Correspondingly, the amount of bowel movements will be diminished, causing less frequent bowel activity, and constipation. If this becomes a problem, a stool softener supplement may be needed, to avoid rectal difficulties.

During the phase of rapid weight loss, calorie intake is much less than the body needs, and protein intake is marginal. The body is in a panic state, like what would happen during a period of starvation. One of the side-effects, in some persons, is inactivation of 30 – 40% (rather than the usual 10%) of hair follicles, causing noticeable amounts of hair to fall out. This is a transient effect, and resolves when nutrition and weight stabilize. We advise patients to avoid hair treatments and permanents, and be sure of adequate protein intake. Sometimes a zinc supplement (no more than 30mgm of Zinc per day) will help, and Minoxidil (a drug to prevent and reverse hair loss) may be tried.

When the body is in a panic state, and trying to combat starvation, it hoards its precious fat until any other usable fuel has been burned. Practically, the body will prefer to burn muscle mass, before consuming its precious fat (don’t ask us why – we didn’t write the rules). If muscle is not regularly used for exercise, like every day, it will be consumed to meet energy needs.

Loss of muscle mass is preventable. It is very important, during active weight loss after surgery (or even when on a diet), to exercise vigorously every day. We recommend at least 20 minutes a day of aerobic activity, and it is well to devote attention to upper body strength as well. Many persons find, after a few weeks or months of regular daily exercise, that they actually begin to enjoy it, and start to work out even more. Fairly vigorous exercise, for more than 30 minutes a day, can greatly enhance fat-burning, and hasten weight loss. It also builds a healthy and beautiful body.

Seriously obese persons are very strong, and powerful – after all, just getting out of bed, you lift more than some people pick up all day long! It’s a shame to let that power be lost, when you need it to enjoy your life, and to make up for all the excitement you’ve put off. Save the power, while losing the fat, and you can just imagine how much energy you can have, and how much more you can accomplish!

OK, so it’s not exactly our fault, but it happens often enough to give a special warning. Many severely overweight women are also infertile, because the fatty tissue soaks up the normal hormones, and makes some of its own as well, completely confusing the ovaries and uterus, and causing a lack of ovulation. As weight loss occurs, this situation may change quickly.

We believe it is important to avoid conception during the phase of rapid weight loss – about one year after surgery – to maintain adequate nutrition. This requires special attention to contraception, even by those who think that it can't happen, because "natural" infertility may not last – in fact, it can go away in one night.

Once weight loss is complete, and nutrition is stabilized, pregnancy is not likely to cause any problems, and will probably be safer than it would be than when obese.  We have studied this, and our findings are reported.   For a copy of this paper, click HERE.

Benefits of Surgical Weight Loss

Finally, we can talk about the good stuff. In our section about the health consequences of severe obesity, we listed problems, or co-morbidities, which affect most of the organs in the body. The remarkable and wonderful fact is that most of these problems can be greatly improved, or will entirely resolve, with successful weight loss. Most people have actually observed this, at least for short periods, after a weight loss by dieting. Unfortunately, with dieting, such benefits usually do not last, because diets don’t last.

We have shown that the weight loss achieved with Gastric Bypass, Roux en-Y can average 80% of excess body weight, and can be maintained for years following surgery. We instruct patients in a very simple program, which is much easier to follow when one is not constantly starving on a diet.

Weight Loss Results after Laparoscopic Gastric Bypass

Now let's look at the health benefits of weight loss:

At least 70% of patients who have high blood pressure, and who are taking medications to control it, are able to stop all medications and have a normal blood pressure, usually within 2 – 3 months after surgery. When medications are still required, their dosage can be lowered, with reduction of their annoying side-effects.

Over 80% of patients will develop normal cholesterol levels within 2 – 3 months after operation.

Although we can't say definitively that heart disease is reduced, the improvement in problems such as high blood pressure, high blood cholesterol, and diabetes certainly suggests that improvement in risk is very likely. In one recent study, the risk of death from cardiovascular disease was profoundly reduced in diabetic patients, who are particularly susceptible to this problem. It may be many years before further proof exists, since there is no easy and safe test for heart disease.

Over 90% of Type II diabetics obtain excellent results, usually within a few days after surgery: normal blood sugar levels, normal Hemoglobin A1C values, and freedom from all their medications, including insulin injections. Based upon numerous studies of diabetes and the control of its complications, it is likely that the problems associated with diabetes will be arrested in their progression, when blood sugar is maintained at normal values. There is no medical treatment for diabetes which can achieve as complete and profound an effect, as surgery - which has led some physicians to suggest that surgery may be the best treatment for diabetes, in the seriously obese patient..

Abnormal Glucose Tolerance, or "Borderline Diabetes" is even more reliably reversed by gastric bypass. Since this condition becomes diabetes in many cases, the operation can frequently prevent diabetes, as well.

Most asthmatics find that they have fewer and less severe attacks, or sometimes none at all. When asthma is associated with gastroesophageal reflux disease, it is particularly benefited by gastric bypass.

Improvement of exercise tolerance and breathing ability usually occurs within the first few months after surgery. Often, patients who have barely been able to walk, find that they are able to participate in family activities, even sports activities.

Dramatic relief of sleep apnea occurs as our patients lose weight. Many report that within a year of surgery, their symptoms were completely gone, and they had even stopped snoring completely – and their spouses agree.

Relief of all symptoms of reflux usually occurs within a few days of surgery, for nearly all patients. We are now beginning a study to determine if the changes in the esophageal lining membrane, called Barrett's esophagus, may be reversed by the surgery as well – thereby reducing the risk of esophageal cancer.

When gallbladder disease is present at the time of the surgery, it is "cured" by removing the gallbladder during the operation. If the gallbladder is not removed, there is some increase in risk of developing gallstones after the surgery is performed, and occasionally, removal of the gallbladder may be necessary at a later time.

This condition responds dramatically to weight loss, usually by becoming completely controlled. A person who is still troubled by incontinence can choose to have specific corrective surgery later, with much greater chance of a successful outcome, with a reduced body weight.

Patients usually experience considerable relief of pain and disability from degenerative arthritis and disk disease, and from pain in the weight-bearing joints. This tends to occur early, with the first 25 -30 pounds lost, usually within about a month after surgery. Of course, if there is nerve irritation, or structural damage already present, it may not be reversed by weight loss, and some pain symptoms can persist.

The Scientific Proof

Measurement of the benefits and outcomes of modern bariatric surgery is one of the most important areas of surgical research in obesity. We are proud to say that we have followed our patients with Laparoscopic Bypass prospectively, and have very solid information never before measured, on the effects of this operation. We have several additional studies in progress, to further measure the improvement in health and lifestyle that weight-control surgery can accomplish.

Weight Loss

We have maintained follow-up with over 90% of the first 300 patients to undergo Laparoscopic Gastric Bypass, Roux en-Y.  The chart below shows average weight loss, as a percentage of Excess Body Weight, for 300 patients between 3 and 48 months following surgery.

Percentage of Excess Body Weight Loss over 3 - 48 Months -- 300 Laparoscopic Gastric Bypasses:

We have studied, and recently reported, the relief of the symptoms of co-morbidities in our patients who underwent Laparoscopic Gastric Bypass. For the first 300 patients who underwent that operation, these are the numbers:

  Condition                                                                          Pre-Operative       Post-Operative

  GastroEsophageal Reflux Disease        180        3
  Hypercholesterolemia        176        6
  Hypertriglyceridemia        106        1
  Diabetes Mellitus (Type II)          59        1
  Glucose Intolerance          30        0
  Stress Incontinence        134        4
  Obstructive Sleep Apnea        150        2
  Hypertension          79                       6
  Arthritis (Symptomatic)        249      20
                                                  TOTAL      1163      43

Over 96% of health problems which are related to obesity are completely resolved and reversed, usually within days to months after surgery. 

That's what fat does to you, and that's what surgery can do to heal you.

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