11851 Jollyville Rd #104
Austin, TX 78759

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Risks and Complications of Surgery

It is impossible to discuss all the complications that can occur following any surgery.

Our goal is to discuss the most important ones and the most common ones. Morbid Obesity, Older age, Number of serious medical problems directly increase the risks following any surgery.

Nutritional Problems

Clinically significant nutritional problems are rare after bariatric surgery as long as all the recommended vitamin and mineral supplements are taken and patient follows up with the surgeons as required. Nutritional issues are more common with the malabsorptive procedures such as duodenal switch and gastric bypass but they can occur in restrictive procedures such as lapband or gastric sleeve. 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 weight loss procedures is the progressive change in attitudes toward eating. Patients begin to eat to live – they no longer live to eat.

Lapband late complications

Late complications with the gastric band may occur several years later and these are typically related to the nature of the implant. Some of these include slippage (approximately 5%), erosion (approximately 1%) and minor tubing and port leaks (approximately 5%). Majority of these complications require surgical procedures to correct but most of the procedures are elective and can be performed with the laparoscopic approach.

Infection with gastric banding

Minor wound infections at port site requiring antibiotics and/ or drainage are rare but do occur. However a major infection related to the band can be dangerous and may require removal of the port or sometimes the whole band. This infection may also lead to other complications and occasionally cause death.


In the United States 1 out of 200 people having obesity surgery die. In the United States alone, over 300,000 deaths every year are reported directly due to obesity. This is about 6-12 deaths per every 200 obese individuals. Statistically, morbidly obese individuals will die 10 – 15 years earlier than normal weight individuals.

Leakage of Bowel Connections

When the surgeon fastens bowel to bowel, or bowel to stomach, the connection is called an anastomosis. We check for leaks at the end of the procedure with an endoscopy and also the next day with an x-ray study. This is to rule out any technical issues for the leak. So no one has a leak at the end of the procedure. However, leak is an issue of healing and therefore presents most often between the 4th and the 21st day. An anastomotic leak will cause leakage of fluid containing bacteria from within the bowel into the abdominal cavity. This can cause a serious infection accompanied by swelling, a rapid pulse rate, and sometimes the formation of an abscess. This is always a very serious complication and its diagnosis and treatment are made more difficult by severe obesity. Generally an immediate operation is required to seal the leak and drain away the infection. Sometimes a Radiologist can place a special drain at the abscess site without need for surgery and reduce the potential for spreading of infection throughout the rest of the abdomen. Sometimes an endoscopy and stent placement is required. Anastomotic leak always causes increase in hospitalization and results in increased discomfort from the drain. Rarely, despite treatment infection may continue and result in sepsis with its associated complications. Rarely the anastomotic leak surfaces via the drain and may result in a fistula.


When surgery is performed some blood vessels must be cut. We do this by tying them with a piece of thread, called a ligature, or by using special device with thermal or ultrasonic energy, or staplers, which coagulate 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, inside the stomach and intestines or at the skin level. Bleeding can also occur internally from the staple lines and anastomosis we create. Generally the bleeding stops on its own with simple fluid support. Rarely the hemoglobin drops enough to require a blood transfusion. It is even rare to require surgery to stop the bleeding.

Bowel Obstruction

After any abdominal operation, scars called adhesions can form in the abdomen. They look like strands of latex or sometimes like a piece of fibrous cord. Adhesions can snag a piece of bowel and wrap itself around the bowel closing it up tight, causing blockage so food and fluid can no longer pass. Sometimes, even many years after surgery, a bowel obstruction may result from adhesions. An obstruction as a result of adhesions must be corrected before the bowel loses its blood supply and dies. Usually an emergency operation is necessary. Occasionally, a bowel obstruction due to adhesions can occur within a few days after surgery. In this case, the adhesions are generally much softer and often come apart on their own. Bowel obstruction may be due to adhesions or due to an internal hernia.

Obstruction of the Stomach Outlet

In Gastric Bypass surgery the stomach is connected to the bowel leaving an opening about 1/2 inch in diameter. This is done deliberately in order to slow the flow of food out of the small stomach pouch and into the small intestine. All healing occurs by scar formation and scars have a tendency to contract. This may cause the opening between stomach and bowel to become too small so that food cannot pass through into the small intestine. This causes repeated vomiting, and must be corrected. This may occur in up to 5% of cases. The treatment is quite simple and can be corrected with an outpatient endoscopy and stretching of the outlet with a balloon dilation. Occasionally gastric ulcers may occur at the outlet and cause the narrowing. This usually heals by medical treatment but rarely re-operation may be required.

Perforation of the stomach/intestine

Perforation of the stomach or the bowel may occur very rarely during the procedure. This would be repaired immediately. However, in some cases the perforation does not occur for several hours or days. Treatment would depend on the condition of the patient at that time and other specific details about the perforation. Generally this would require a second operation. This may or may not be performed using the laparoscopic approach.

Spleen injury requiring removal

The spleen is a friable organ and lies very close to the upper part of the stomach. Sometimes the spleen is very tightly attached to the part of the stomach being operated on and could be injured with surgical instruments or simply by pulling on it during manipulation of the stomach. Once the spleen is injured it may bleed severely and may necessitate its removal. This, in some cases may require conversion to open procedure.

Liver and other internal organ injury

The liver lies over the upper part of the stomach and may be injured during the procedure. Most often this does not require any intervention and heals by itself. Rarely conversion to open procedure may be necessary to stop the bleeding and repair the damage. Other internal organs may be injured with the surgical instruments or manipulation during the procedure. Any damage would be repaired immediately and most often this can be accomplished without conversion to open approach.


This is an extremely rare but serious complication of any abdominal surgery in the vicinity of the pancreas. This would prolong the hospital stay but does not usually require any surgical procedures to treat.

Esophageal injury

In rare cases esophageal injury may result from instruments used during the laparoscopic approach to perform the procedure. Esophageal injury may cause a leak. If the leak is immediate, it will be repaired. However some injuries present several days later as a leak. In these circumstances surgery will be required and the band may need to be removed because of potential for infection.

Heart Attack

May result in permanent heart damage or death. This is a risk with any major surgery.

Congestive Heart Failure

Patients with pre existing heart disease, especially on medications for heart failure are at risk. A heart attack after surgery may also result in this complication.


Irregular heartbeat may occur during anesthesia or after the surgery and may be dangerous if not recognized and treated promptly.


A rare complication following surgery and it is more common in patients with pre- existing vascular disease.”


This condition is a partial collapse of a part of the lung usually after general anesthesia caused by lack of motion of the chest wall. Normally, your lung is filled with tiny air spaces that remain open allowing air to fill the lung and expand. Lack of motion and weight of the chest wall can allow these tiny pockets to collapse or fill with fluid resulting in your body not receiving the oxygen it needs to recover and heal itself. If left untreated, atelectasis can cause a more serious complication, known as pneumonia. The best treatment is to prevent this from happening by performing deep breathing and lung exercises. We teach you these techniques before surgery and encourage you to do them repeatedly, after the operation. We also have special treatments to help you and your lungs recover if atelectasis should occur.


Pneumonia is an infection in the lungs. After surgery it can be especially serious because the infecting organisms usually will come from the gastrointestinal (GI) tract. These types of organisms can be very destructive. The risk of pneumonia can be minimized by deep breathing and coughing after the surgery. We also require that patients stop smoking at least 30 days prior to their surgery to help prevent this complication from occurring.

Deep Vein Thrombosis and Pulmonary Embolism

This is the most common cause of death in the 1 in 200 patients who die after obesity surgery. People who have an operation don’t like to move around or exercise their legs. Because of this blood becomes stagnant and may form clots in the leg veins. 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 great deal of strain and it may fail suddenly. This can cause death. Although these can occur at any time, they are more likely in the overweight patients especially at the time of and soon after surgery.

We want to prevent a pulmonary embolism from occurring by thinning the blood with heparin making it less likely to clot and by prescribing stockings to compress the legs and keep the blood flowing faster through the veins. We try to get the patients up to walk as soon as possible. Sometimes in very high-risk patients we prescribe heparin injections for two to four weeks after the surgery. You can help by quitting birth control pills 30 days prior to surgery and be as active as possible before the surgery. No matter how hard we try we can’t prevent pulmonary embolism in all patients but we can reduce the risk together using the available methods as described above.

Urinary Tract Infection

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

Wound Infection

A wound infection is a type of abscess and is treated by drainage. Morbidly obese persons have a very deep layer of fat under the skin, which predisposes to wound infection.


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, an infection or abscess may occur. The treatment of any abscess is to drain away the infected fluid and kill the bacteria with antibiotics. We want to prevent abscesses by trying to avoid any collections of fluid or blood in the abdomen at the time of surgery. We may place a drain to help remove fluid collection after surgery. If an un-drained abscess develops, we have specialists called interventional radiologists, who often can achieve drainage and resolve the problem without needing another operation to drain it.


An uncontrolled leak or perforation or an abscess that is not drained will sometimes cause severe infection in the body termed as sepsis. This condition is rare but is serious and requires intensive care, antibiotics and may require ventilation depending on the clinical condition of the patient. Other complications including death may follow but fortunately this situation is very rare.

Heparin Effect

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 work at finding 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 blood loss occurs it may cause the pulse and blood pressure to become unstable. A blood 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. Donating your own blood and having it saved for your surgery – a procedure called autologous donation can reduce these risks. Please check with the hospital for availability of this service. The risk of needing a blood transfusion during and following surgery is relatively low. When patients decline to receive blood or blood products for religious reasons, we will honor a  commitment to avoid transfusion on your instructions after you sign a special consent.

Development of Gallbladder Disease

The purpose of the gallbladder is to store bile, which acts as a detergent to help in the digestion of fats. When a fatty meal is eaten, bile makes it possible to dissolve and absorb the fat. Following surgery you will be required to drastically reduce your consumption of fatty foods. Since the gallbladder is less likely to use the stored bile, it may develop gallstones and surgical intervention may become necessary to have it removed. As many as 10% of patients having weight loss surgery may develop symptoms of gallbladder disease within three years following their surgery. Routine gall bladder removal with weight loss surgery is no longer recommended.

Kidney and Liver Problems

Very occasionally sudden kidney failure may result secondary to blood loss, dehydration, IV contrast dye or infections and sepsis. This is a rare event and may require dialysis short or long term. Continued consumption of alcohol use following gastric bypass surgery may be damaging to the liver. Alcohol consumption should not exceed 2 small cocktails in a week period. Intoxication occurs quickly due to alcohol entering the small intestine shortly after ingestion and is readily absorbed by the liver. Blood alcohol levels reach legal limits much quicker and with smaller amounts of alcohol.

Nutritional Problems

Nutritional problems are 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 weight loss procedures is the progressive change in attitudes toward eating. Patients begin to eat to live – they no longer live to eat.

Protein Deficiency

Protein is the primary component in our muscles, organs, heart, and brain. Our bodies require a constant supply of protein building materials to repair and replace tissues that become worn out or damaged. The Gastric Bypass reduces the capacity of the stomach to a very small volume so 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 unlikely to occur. You need to maintain a minimum of 70 gm protein intake daily for life.

Vitamin Deficiency

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 initially is much less and does not supply complete nutrition. In order to have any chance of getting enough vitamins, a high potency multivitamin supplement must be taken daily. We think it is safest to do this for the rest of your life after this type of surgery. In addition, we have seen a few patients develop deficiency of Vitamin B-12 even when taking a multi-vitamin supplement. B-12 binds to a factor in the stomach, which is largely bypassed with the gastric bypass 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. Vitamin B-12 deficiency can develop without warning and becomes very dangerous to ones health and wellbeing.

Mineral Deficiency

We recommend a multivitamin preparation containing mineral supplements in generous amounts. We also recommend daily use of calcium citrate. Many patients, particularly women, will require a special iron supplement to maintain adequate iron stores to prevent anemia.


There are several complications that are not listed in this manual. In fact it is impossible to discuss all possible complications because anything may happen and one complication may lead to another. Some of the others are listed below. Discuss any specific concerns you have with your surgeon.

  • Electrolyte abnormalities
  • Low white blood cell count
  • Anemia
  • Low blood sugars
  • Nesidioblastosis (rare)
  • SMA syndrome
  • Neuropathies that may be permanent
  • Ulcers on the stomach or pouch
  • Internal hernias
  • Psychosocial Problems
  • Post-operative Depression
  • Dysfunctional social problems
  • Unrelenting nausea and vomiting.