Gastrointestinal Complications After Gastric Bypass Surgery

by John Yadegar, MD - April 2006

Obesity is a catastrophic disease that afflicts more than 100 million Americans, causing 400,000 deaths per year due to its associated diseases and costing our nation billions of dollars annually.

OBESITY HAS MULTIPLE CAUSES, which include genetic predisposition, environmental triggers and behavioral tendencies. It negatively impacts every system in the human body: it affects the nervous system by causing various psychological problems such as depression and an increased rate of strokes, hence disability; it affects the respiratory system by causing shortness of breath and sleep apnea, which requires oxygen therapy; it affects the cardiac system by increasing risk of heart attacks due to increased workload; it affects the gastrointestinal system by increasing acid reflux; it affects the endocrine system by contributing to hyperlipidemia and diabetes; it affects the genitourinary system by causing incontinence, lack of libido and reduced fertility; and it affects the musculoskeletal system by increasing wear and tear on the weight bearing joints. In addition, obesity increases the risk of developing breast, prostate, uterine or colon cancer.

A national effort is now under way to tackle this problem. A healthy diet and regular exercise for life can never be replaced and should always complement any weight reduction initiative, whether surgical or not. The current trend in the USA is the surgical approach. This takes many forms and the individual patient should research the pros and cons of each one and seek expert advice from surgeons who are trained in the field and meet the standards established by the Centers of Excellence.

The gold standard is the laparoscopic Roux-en-Y gastric bypass surgery. It is a minimally invasive approach in which a small pouch is created from the patient’s own stomach and reconnected to the small bowel in such a way as to bypass about 100 cm of the absorptive length of the small intestine, thereby creating both a restrictive and a malabsorptive component to help achieve the desired weight loss. The laparoscopic method allows for a faster recovery period than the traditional open approach, which is still performed by some surgeons.

Other procedures include the placement of silicone bands to restrict the stomach or operations that bypass long segments of the small intestine, causing a greater malabsorption tendency.

All surgeries carry a certain degree of risk, and a well informed patient will often choose the right option. The gastrointestinal complications of all the gastric bypass operations are very similar. They can occur immediately, early or late in the postoperative phase.

The immediate complications include injury to any of the gastrointestinal organs, particularly the esophagus, stomach, small and large bowel, liver or spleen. These injuries may be minor or major. They range from tears in the small bowel, which are often easily fixed, to hemorrhage from a torn spleen that would then have to be taken out. These injuries may happen due to complexity of the case, operative errors with instruments and mishandling of the organs. Esophageal or gastric injury may be challenging to fix. The surgical stapling devices currently used are extremely reliable; nevertheless they may misfire, in which case manual repair needs to be done. Spillage of gastrointestinal contents into the abdominal cavity can act as a rich medium for growth of bacteria and formation of an abdominal abscess or wound infections. In such cases, conversion to open surgery may be required.

Early gastrointestinal complications may occur anytime in the first month after surgery. The two most life-threatening complications are: 1) gastric remnant distention and rupture, which may prove fatal if unrecognized; and 2) anastomotic leak, which is either a technical failure due to inadequate closure of the divided and rejoined bowel or inadequate healing due to poor patient constitution, environmental factors such as drugs (steroids) or noncompliance with dietary advice or smoking cessation. The integrity of the anastomosis is checked intra-operatively by various techniques. Both these complications, if recognized early, may be treated by insertion of drains and use of antimicrobials, although surgical intervention is needed in some cases.

Delayed bleeding from staple lines or a small blood vessel in the omentum or small bowel mesentery may occur within the first 48 hours. This may not have been noticed intra-operatively as under CO2 insufflation, small bleeding vessels are occluded temporarily. In addition, the use of anticoagulation such as low molecular weight Heparin on a routine basis with patients may predispose them to this problem or exacerbate it in one to two percent of the cases. This problem is often self-limiting; however, some of the patients may require blood transfusion or return to the operating room if the bleeding does not stop.

Infections may occur within the first week. It may take the form of a port site wound infection or in an open case, the form of an incisional wound infection. The majority is treated with antibiotics. Occasionally the wound may need to be opened. Th e incidence of wound infection varies from one to ten percent, according to the method, laparoscopic or open surgery, respectively.

Gastric pouch jejunojejunostomy or delayed emptying may occur on days two through ten. This is often due to edema at the anastomosis, which is self-limiting. Small blood clots may also contribute to this, or there may be other causes such as viral gastroenteritis. Often time, when the patients experience nausea or vomiting, they need to be admitted to the hospital for IV hydration. If nausea, vomiting or delayed emptying continues, one should consider a workup with a CT and/or UGI series. Technical errors or internal herniation should be ruled out. A second look operation is mandated if the surgeon suspects the latter.

Once the patients start oral intake, they need to avoid any high sugar or carbohydrate loads, otherwise they will experience “dumping” syndrome. Early dumping is characterized by feelings of abdominal distension, nausea, lightheadedness and feeling unwell, (resulting from the water drag into the bowel in response to the carbohydrate load). This is followed by late dumping, which is characterized by sweating, lightheadedness and tremors, all due to the overriding insulin response to the sugar load.

Late gastrointestinal complications can occur anytime after 30 days. These include gastric or jejunal perforation secondary to an ulcer (one to three percent). This often occurs on the jejunal side of the gastrojejunostomy and may be caused by poor blood supply to the area, tension in the anastomosis (poor surgical technique), use of non-steroidal anti-inflammatory drugs, steroids, smoking or non-compliance with proton pump inhibitors (PPI). The symptoms are often abdominal pain, nausea, fever and lack of progress in diet. A workup with CT, UGI or EGD (low insufflation) is required, and the treatment includes cessation of the insult, use of PPI and surgery if the perforation has not sealed. Bleeding ulcers may also be present in a compromised patient. The mainstay of workup and therapy is the same as with any GI bleeding.

Internal hernias due to newly created anatomical planes causing partial or total obstruction can present with vague abdominal symptoms, such as pain and distention with nausea and vomiting. They may be difficult to diagnose, but abdominal CT is often helpful. A low index of suspicion is required and surgery is the treatment of choice. This occurs in one to three percent of cases.

Incisional hernias are much less common if the operation is done laparoscopically (one versus twenty percent). If they require repair, optimal time is one to two years after the initial surgery, as the weight loss will make the surgery easier, unless there is evidence of strangulation, in which case immediate attention is needed.

Pouch outlet or jejunojejunostomy stenosis is a well recognized complication that may present signs and symptoms of obstruction. This has been noticed more with the circular stapling of the gastrojejunostomy. Patients may have difficulty swallowing and may necessitate an EGD with balloon dilatation.

Two less common complications include a gastrogastric fistula and bezoar. Gastrogastric fistulas may be an incidental finding, or may be found in the workup of a bariatric patient who is failing to progress. If asymptomatic they may be left untreated. A bezoar may be a bolus of plant or meat matter that has accumulated and obstructed the pouch or even the jejunostomy outlet. This often happens as a result of consuming the wrong type or consistency of food or at an earlier than recommended time frame. Treatments include the use of cellulase (to digest plant matter), meat tenderizer to digest meat proteins, EGD to extract the bezoar, or surgery.

Formation of gallstones due to change in the constitution of bile after gastric bypass has also been recognized. The approach to elective cholecystectomy or use of Actigall postoperatively varies. A reasonable algorithm is to perform the laparoscopic cholecystectomy at the same time as the bypass only if the patient is diabetic, with history of gallstones and an attack of biliary colic in the past six months. Otherwise, it is best to perform it later, when the patient has already lost weight. The yield is low if removing all the gall bladders electively (less than ten percent will develop gall bladder complaints).

One has to remember that the gastric remnant is predisposed to the pathology as before, e.g., gastric neoplasm, and may need to be assessed, except that now it can not be visualized by routine endoscopy and other modalities (radiological or surgical).

Finally gastric bypass patients should remain on lifelong multivitamins, Calcium, B12 and sometimes iron. Their blood levels should be monitored every three months and appropriate therapy introduced, otherwise metabolic complications and deficiencies may arise.

A brief mention is warranted for gastric banding. As a foreign body, it may get infected, slip, erode into the stomach, rupture or malfunction or cause hypersensitivity, any one of which may lead to its removal. The weight loss of two years is about 50 percent of the excess body weight versus 70-80 percent with the laparoscopic Roux-en-Y gastric bypass surgery.

The long limb bypass and the biliopancreatic diversion with or without duodenal switch are more selective operations. They cause more GI symptoms such as flatulence, diarrhea and malabsorption.

In summary, gastric bypass surgery, like all other therapeutic modalities, carries certain risks, some of which affect the gastrointestinal system. However, a good patient selection criteria, the correct operation performed by a well trained surgeon with a multidisciplinary approach, regular patient follow-up, and a patient who is compliant with the diet, supplements, exercise and change of lifestyle, will yield the best outcome.

John Yadegar, MD
Medical Director of Minimally Invasive & Bariatric Surgery, Lancaster Community Hospital Assistant Clinical Professor of Surgery, UCLA Medical Center