OHSU

Benefits and Risks of Surgery

Risks of Weight-loss Surgeries

For most patients, surgery to accomplish weight loss (bariatric surgery) is safe and effective. However, bariatric surgery is major surgery and as such is associated with the risk of the development of postoperative complications. In addition, patients with severe obesity experience an increased risk of postoperative complications following surgery in general. Thus, complications may occur as the result of the performance of major surgery in general as well as specific complications to the type of bariatric surgery which is done. General risks to all bariatric as well as other major abdominal surgery include, but are not limited to, bleeding, wound complications such as infection, damage to other organs in the operative area, development of blood clots in the legs which may break loose and result in pulmonary embolism, pneumonia, heart complication such as heart attack, or obstruction of the small bowel.

 

Short Term Complications

Short term risks related to bariatric operation itself include: anastomic leakage (leakage areas where the stomach and/or bowel is reconnected), intestinal obstruction (blockage may occur due to a narrowing at the site of one of these anastomoses due to swelling), bowel twisting, or other complication.

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Bleeding

Bleeding may occur following any major abdominal operation. In some cases, reoperation to control the bleeding or one or more blood transfusions may be required. Such bleeding in bariatric surgery is most often due to injury of the spleen which, in some patients, is unavoidable due to enlargement and location of the spleen next to the stomach where the bypass is done. The incidence of such bleeding is about 5%. In rare cases (less than 1%), removal of the spleen is necessary to control the bleeding.

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Wound Complications

Patients with obesity experience a relatively high incidence of complications of the wound due to increase susceptibility to developing infection. Patients who require open surgery have a higher risk of wound infection and incomplete healing which leads to a delayed hernia. This may occur in as many as 30% of patients who require open surgery and often requires a second operation following weight loss to repair the hernia.

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Damage to Organs in Operative Area

In addition to the spleen discussed above, injury to the stomach, intestine, or liver may occur as the result of the need to do operative manipulation in order to complete the surgery. In occasional patients, such injuries are not visible to the surgeon and require reoperation for repair when evidence of postoperative infection occurs.

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Pulmonary Complications

Complications involving the lungs may occur following bariatric surgery. Breathing is more difficult for obese people and in turn is worsened by the operation itself. As the result, areas of collapse of lung, pneumonia, and worsened obstructive sleep apnea may all occur and lead to insufficiency of the lungs. In these cases, support with a respirator or breathing machine may be necessary for a matter of days or longer until recovery from the surgery occurs. Pulmonary embolism may also occur in overweight patients. In this situation, clots that form in the legs associated with the surgery break loose and pass through the blood vessels into the lungs where an obstruction can be life threatening. An effort is made to prevent these blood clots from forming by the use of a low dose of anticoagulant (blood thinner) and special compression stockings on the legs during the surgery. Despite these preventative measures, blood clots may still occur.

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Gastrointestinal Obstruction

A blockage may occur when narrowing occurs at the site of connection of the stomach and bowel or where the intestine is sutured to itself as part of the gastric bypass procedure. Swelling at the site of these anastomoses may also cause temporary blockage. In these cases, the patients may not tolerate their oral liquid feedings and require intravenous support until the condition resolves. In the case of a narrowed anastomosis, an endoscopy may be necessary to stretch the anastomosis with a balloon. Kinking or twisting of the intestine can occur after any abdominal surgery but is more common after bariatric surgery. Should this occur, a reoperation is most often necessary to correct the problem.
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Other Complications

Still other complications may occur during or immediately following surgery that are less common but still possible. These include but are not limited to complications of the anesthesia, allergy or adverse reaction to a medication, development of a bed or pressure sore due to the weight causing skin breakdown, and temporary injury to nerves causing either numbness or rarely muscle weakness may occur due to positioning on the operating table combined with the weight. Obese people may have difficulty with establishing venous access (starting an IV) and a complication related to the IV may occur.

A postoperative ulcer of the stomach or intestine is possible. These ulcers may cause bleeding, stricture, and/or pain. Acid suppressive medication is routinely used in an attempt to prevent these ulcers. Should an ulcer occur, an endoscopy may be required to establish the diagnosis. Most ulcers are resolved with antacid medication.

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Late Complications of Bariatric Surgery

Complications can also occur beyond 30 days after surgery.

Inadequate or Excessive Weight Loss

While excessive or too much weight loss following bariatric surgery is rare, loss of less weight than anticipated or is necessary to improve the related comorbid conditions may occur. In addition, some degree of regain of weight two to five or more years after bariatric surgery definitely occurs in some patients. The key factors that are involved in weight loss or regain of weight include the number of calories that are eaten and the amount of physical activity that is accomplished. As time passes it becomes possible to eat relatively more and more often than is possible in the early weeks following bariatric surgery, particularly with gastric bypass. It is therefore necessary to maintain a careful surveillance over the dietary practices that evolve during the first two years following bariatric surgery. Frequent follow up visits to review the changes in dietary intake which inevitably occur is a necessary component of a successful long term result. Establishment of a physical activity program is also of great importance to avoid excessive regain of weight or inadequate initial weight loss.
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Gastrointestinal Complications

Many of the complications that may occur early after surgery discussed above, including ulcer, stricture, or intestinal obstruction, can also occur late. While uncommon, it is possible to need reoperation to correct such problems. Patients who undergo gastric bypass may undergo dumping syndrome. This refers to a sense of weakness, nausea, sweating, rapid heart rate, and diarrhea which may follow soon after eating a meal. This can be avoided by eating very slowly, avoiding liquids during meals, and avoiding foods that contain sugars. Diarrhea may follow bariatric surgery as well but is usually not a serious problem.
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Bone Disease

Although the reported incidence of broken bones following bariatric surgery is very low, osteoporosis and development of fractures is very common elderly patients, especially women. It is possible that bariatric surgery would lead to loss of bone mass, or shrink, and fractures particularly if calcium and/or vitamin D intake is inadequate. The risk is raised in patients who develop chronic diarrhea. Careful monitoring and supplementation is indicated to diminish the chance for this complication.

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Gallstones

The risk of development of gallstones is increased in overweight people such that many patients have already had gallbladder surgery before the bariatric surgery is done. In those patients who still have their gallbladder, rapid weight loss is known to increase the chance for development of gallstones particularly during the first six months following gastric bypass. A medication can be taken which greatly reduces this risk.
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Ventral Hernia

Incomplete healing of the wound is discussed under early complications. It may in fact take one to two years before the presence of a hernia is known. Operative repair of these hernias is usually done as the most common course is for the hernias to gradually get larger. There is a risk of intestinal obstruction if the bowel gets caught in the hernia.

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Nutritional Deficiency

Any number of nutritional deficiencies may occur as the result of the dramatically decreased intake of nutrients that follows bariatric surgery. Routine supplementation with vitamins and minerals is recommended prior to and indefinitely following bariatric surgery. Protein deficiency is the most common problem early after surgery. Special attention must be made to the protein intake in order to avoid diminished wound healing, loss of muscle mass and strength, and loss of hair. Other deficiencies that may occur include iron which causes anemia. Supplementation with iron should be routine. Failure to take vitamins or recurrent vomiting may cause a deficiency of B vitamins which can cause neurological complication, both the brain and nerves in the extremities.

In summary, there are many possible complications early and late following bariatric surgery. It is for this reason that every effort must be made to identify all problems before the surgery and to optimize the patient's condition before the surgery is done. Following the surgery, careful attention to all of the recommendations regarding diet, activity, supplementation, and monitoring for possible complications must be followed. Follow up in the bariatric surgery clinic is required to look out for the development of these complications so that they may be prevented or detected and treated early, should they occur.

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Risks of Laparoscopic Adjustable Gastric Banding

Major or life-threatening complications following laparoscopic adjustable gastric band placement are uncommon and deaths are rare due to the lesser extent of the operative procedure which is required compared to gastric bypass. The stomach and small intestine are not divided and there are no connections or anastomoses which must heal and have the potential to leak, as discussed under the risks of gastric bypass. The operations are generally shorter and are followed by more rapid recovery. Nevertheless it is possible for life-threatening complications to occur. These may include injury to organs by placement of the operative trocars, or injury to the spleen or liver with secondary bleeding which may occur in the process of getting the band in place about the stomach. Injury to the stomach leading to peritonitis, a life-threatening infection, is also possible although very uncommon. The reported mortality risk is lower for gastric banding compared to gastric bypass and other more extensive operative procedures, estimated to be in the range of 1/1000.

Even though gastric banding is safer from the standpoint of severe or life-threatening complications, complications requiring reoperation definitely occur and with similar frequency as those following gastric bypass. The complications include malposition of the band with secondary persistent vomiting, malposition of the port such that the tightness of the band cannot be adjusted, or infection of the foreign body (band) requiring its removal. Longer term complications of gastric banding may include erosion of the band through the stomach wall which also requires removal of the band, slippage of stomach through the band creating an obstruction and persistent vomiting (this complication requires reoperation for correction), or damage to the port or balloon which may cause leakage of the fluid that tightens the band thereby reducing its effectiveness.

Some patients may experience persistent vomiting, gastroesophageal reflux, aspiration causing cough or pneumonia, and disappointing or inadequate weight loss to achieve the original surgical goal. Persistent vomiting may cause nutrient deficiencies including thiamin, which can cause brain damage. Compliance with the recommended vitamin replacement regime is essential as are follow-up visits for adjustment of the tightness of the band and review of lifestyle changes including diet.
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OHSU is the premier bariatric surgery center for the treatment of obesity in Portland, Oregon. We look forward to serving you. Please contact us at 503-494-1983.

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