About this process
The gastric bypass is a combined restrictive and mal-absorptive procedure.
- The first step is that the surgeon creates a small stomach pouch using metal staples, similar to stitches. The stomach will be cut through so that the pouch is no longer attached to the rest of the stomach. This top section of the stomach (the pouch) will hold your food.
- The surgeon will count down 75–150cm from the top of your small intestine and divide it in two. They will then bring up the lower end of the intestine and bring it up and attach it to your small stomach (pouch). Food will now travel from the pouch straight into the lower part of the small intestine.
- The main part of your stomach is left inside your abdomen and continues to have a blood supply. No food passes through this part of the stomach but it still produces digestive juices. It is attached further down the small intestine to allow these digestive juices to mix with your food.
- The amount of food you are able to eat is reduced, meaning you will fill up quickly and stay full for longer. Most people find that they do not get the same feeling of hunger that they did before the surgery.
- The bypassed portion of stomach and intestine does not affect the absorption of most of the nutrients that you eat. However it may reduce the amount of protein, vitamins and minerals that you absorb. To avoid developing complications such as nausea, vomiting or a nutrient deficiency, it is essential that you follow the dietary advice recommended.
- You also need to take the daily lifelong vitamin and mineral supplements prescribed. You will require regular blood tests to ensure you do not develop any nutritional deficiencies.
Most people lose weight quickly over the first year following bypass surgery, generally reaching their target weight after 18 months.
On average, people lose 65–75% of their excess body weight. Adherence to dietary advice and regular exercise key to achieving greater weight loss and better weight maintenance. The dietitian will discuss changes to make to your eating patterns to achieve the best weight loss results.
- The amount of food you can eat is restricted
- You are likely to feel satisfied sooner and for longer
- Weight loss starts from the time of surgery
- You can lose on average 65–75% of your excess weight
- It is unusual for a patient not to lose the expected amount of weight
- The gastric bypass procedure is effective at reducing medication requirements and improving blood sugar control for patients affected by type 2 diabetes mellitus
- Gastric bypass surgery is major surgery and involves cutting and stapling of the stomach and intestines.
- Obstruction can occur where the new connections are created at the pouch and further down the intestine - this may require a procedure to widen the area.
- You will need to take daily multivitamin and mineral supplements for life.
- You will be at greater risk of suffering from nutritional deficiencies such as vitamin B12, iron and calcium.
- Your hair may thin temporarily while rapidly losing weight.
- You may experience dumping syndrome - it is not considered a health risk but symptoms include nausea, vomiting, diarrhoea, sweating, faintness, weakness and increased heart rate (this tends to wear off one year after surgery).
- Nausea and vomiting may occur in the first few days after surgery or if you eat too quickly/too much.
- Weight regain can occur if you do not adhere to long term dietary, exercise and lifestyle changes.
As with any surgery there are possible complications, including:
- Heart attack: obese patients are at increased risk due to higher cardiovascular risk factors such as blood pressure, type 2 diabetes, and high cholesterol.
- General anaesthesia complications: obese patients are at higher risk.
- Pulmonary embolism: this occurs when a blood clot in the leg breaks off and travels to the lungs. In such cases most patients develop sudden shortness of breath but it can cause sudden death in about 1% of patients. You will be put on blood thinning medication and given compression stockings while in hospital to prevent this. The blood thinning medication will need to be continued for two weeks after you are discharged.
- Infection: the risk of infection is generally low. Wound and urinary infections are rare and if they occur, can be treated with antibiotics. Likewise lung infections are rare if you follow post-operative respiratory physiotherapy guidelines. You may be given medication to prevent infections before you go home.
- Ulcers: the risk of ulcer formation significantly increases if you smoke.
- Leaks: leaks can occur where the bowel, stomach and intestine are stapled or sewn. If a complete seal does not form, bowel contents can leak into the abdomen causing a serious infection. This occurs in about 0.5-3% of cases. If a leak is suspected, you may require further surgery.
- Bleeding: bleeding occurs in 3-5% of cases and is usually resolved by stopping any blood thinning medication you are on. Occasionally surgery may be needed to stop the bleeding.
- Gallstones: you may develop gallstones due to rapid weight loss. It may be necessary to undergo a further operation to remove your gallbladder, although this is quite rare.
- Bowel obstruction: this can be caused by scar tissue in the abdomen, kinking of the bowel or the development of an internal hernia. It occurs in up to 5% of cases and a further operation may be needed to correct it.
- Spleen injuries: these are rare but can occur during surgery and in some cases the spleen may have to be removed.
- Incisional hernia: this is rare when using laparoscopic (keyhole) techniques. If it occurs a hernia repair operation will usually be required.
- Death: there is about a 1% risk of death associated with surgery. This can depend on the surgical procedure and your clinical condition.