Gastric Bypass Surgery

Gastric bypass is a surgical intervention performed with the aim to help obese people to lose weight. The procedure changes the morphology of the stomach and intestine conditioning them to absorb less calories and making you feel full with a reduced food intake.

The surgery cannot be undone. 

Gastric Bypass Procedure

The gastric bypass procedure requires general anesthesia and deep sedation. The surgery can be divided into two steps:

1. During this first step, the stomach will be made smaller. The surgeon will use staples with the aim to separate the stomach into sections: a small upper and a larger bottom section. The upper part of the stomach will be capable of holding a volume of about 1 ounce or 28 grams and will have the size of a walnut. Thanks to this transformation the patient will eat less than before the operation and will feel satiated with just a small amount of food.
2. This step is defined as a gastric bypass.  During this procedure, the surgeon will connect a small part of the jejunum (small intestine) to a small hole in the upper stomach section. As a result, the food will follow this new route during digestion, allowing fewer calories to be absorbed during the process.

The gastric bypass can be performed in two ways:

• open surgery
• endoscopic surgery

A large incision in the abdomen characterizes the open operation. The bypass will be performed connecting the stomach straight to the small intestines.  The endoscopic surgery uses a camera known as laparoscopy. This camera will be collocated in the abdomen. During the procedure, the surgeon will perform between 4 to 6 small incisions. The instruments will be inserted into the abdomen through these incisions. A video monitor is connected to the camera in the operating room allowing the surgeon to observe inside the stomach during the operation.  The principal advantages of this intervention are fast recovery after the surgical intervention as well as shorter hospital stay, less pain than the other techniques and minimal scars with a reduced risk of incisional hernias or infections at the operation site. The laparoscopic surgery usually takes between two and four hours.

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Indications of Gastric Bypass Surgery

The indications of this type of surgery is based on the conditions and characteristics of the patient. Obesity is associated with the development of severe chronic diseases, such as arterial hypertension and diabetes mellitus, which have high complications and increased mortality rates.

The Gastric Bypass surgery has been proved to decrease the incidence of these complications and diminish the associated mortality.  The selection of patients for this type of surgery is evaluated by a multidisciplinary team including physicians, bariatric surgeon, and a nutrition specialist.

This surgical procedure is considered a major abdominal surgery with several possible complications. For this reason, it is only reserved for specific type of patients. The criteria are:

1. Presence body mass index (BMI) of 40kg/m² or more.
2. Patients are well informed and motivated.
3. Patients with an acceptable risk for surgery.
4. Patients who already have attempted to lose weight by non-surgical means.
5. Patients with BMI >35kg/m² with chronic diseases such as diabetes mellitus, sleep apnoea, joint disease, or obesity-related cardiomyopathy.

Contraindications of Gastric Bypass Surgery

The Gastric Bypass surgery is considered a major abdominal surgery. It is contraindicated in the following cases:

• Major depression
• History of drug or alcohol abuse.
• Eating disorders.
• Cardiac disease with high anesthetic risk.
• Bleeding disorders.
• Patient unable to comply with the nutritional needs post-procedure
• Patients under 18 years and over 65 years.

Complications of Gastric Bypass Surgery

The gastric bypass surgery as an abdominal surgery presents several difficulties. The risks become higher in obese patients. Different studies have shown complications which are only related to this type of surgery.

Generally speaking, possible complications for abdominal surgery are:

• Infections: it can be located on the surgical incision, or to the level of the internal surfaces and organs. Obesity constitutes an essential factor with a negative impact on the development of infection after the operation. This risk is usually well managed with the use of intravenous antibiotics such as 3rd generation cephalosporins.
• The risk of bleeding is high in obese patients due to the presence of the extra tissue that needs to be removed.
• Herniation. A hernia can appear around the surgical incision or it can form internally.
• Bowel obstruction. The bowel obstruction is not a common complication. It is usually secondary to internal hernias or to the development of adhesions or fibrosis.
• Pulmonary embolism. The pulmonary embolism is a fatal complication. Its rate is increased in obese patients and with major abdominal surgeries.

Complications related specifically to the gastric bypass procedure are:

• Leakage from the surgical connection of the stomach and the small intestine.
• The shrinkage or stricture of openings into the intestine is another type of complication usually associated with this type of surgery
• Nausea or vomiting, from eating more than what the new stomach (the pouch) can hold.
• Gallstones, as a result of the rapid and substantial weight loss.
• Nutritional deficiencies. The deficiencies are very common due to weight loss and malabsorption.

Postoperative management of Gastric Bypass Patients

After the operation, most patients can go home in a week. The patient should be free of symptoms such as pain, vomiting, and diarrhoea.

The patient will receive nutritional counseling and will have to follow a new diet. Also, the patient needs to know how to prevent nutritional deficiencies. The patients will need a very close follow-up and continuous motivation to avoid difficulties and to properly manage the evolution of previous existing conditions, such as diabetes or hypertension.

The weight loss is excellent in nearly all patients, with typical losses of about 4.5kg a month, stabilizing after 24 months. Most of these patients will need cosmetic surgery (abdominoplasty or “tummy tuck”, brachioplasty, etc.) with the aim to remove the excess skin after weight-loss.

This surgery provides critical improvements in obesity-related conditions such as diabetes mellitus and arterial hypertension, joint pain, increased mobility and ability to perform daily living activities, lower inflammatory state due to lower visceral fat, and much more!

References

1. Walter J. Pories. Bariatric Surgery: Risks and Rewards. J Clin Endocrinol Metab. 2008 Nov; 93(11 Suppl 1): S89–S96.doi: 10.1210/jc.2008-1641
2. Kissler HJ, Settmacher U. Bariatric surgery to treat obesity. Semin Nephrol. 2013 Jan;33(1):75-89. doi: 10.1016/j.semnephrol.2012.12.004.
3. Athyros VG, Tziomalos K, Karagiannis A, Mikhailidis DP. Cardiovascular benefits of bariatric surgery in morbidly obese patients. Obes Rev. 2011 Jul;12(7):515-24. doi: 10.1111/j.1467-789X.2010.00831.x. Epub 2011 Feb 23.
4. Bondada S, Jen HC, Deugarte DA. Outcomes of bariatric surgery in adolescents. Curr Opin Pediatr. 2011 Oct;23(5):552-6. doi: 10.1097/MOP.0b013e32834a1b49.
5. Nocca D.Laparoscopic adjustable gastric banding and laparoscopic sleeve gastrectomy: which has a place in the treatment of diabetes in morbidly obese patients? Diabetes Metab. 2009 Dec;35(6 Pt 2):524-7. doi: 10.1016/S1262-3636(09)73460-3.

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