Weight loss surgery – Roux-en-Y gastric bypass

It is not a new operation. It was first described by Mason in the 1970s to overcome the side effects of the then popular weight loss operation, Jejuno-ileal bypass. For many years it was performed as an open operation, but most primary bypasses are now performed with keyhole (laparoscopic) surgery.

There are several different ways of performing a bypass. One way is to add malabsorption to the restriction by increasing the length of bypassed bowel (D variety). Another way is to perform a single anastomosis (or Mini) bypass. This has the side effect of bile refluxing into the gastric remnant and increases the risk of gastric cancer 20-30 years later. Although technically easier, we do not favour this approach because of the cancer risk. Depending on circumstances, because of that risk we use the standard or D bypass. This diverts bile away from the stomach rather than into it.

Bypass produces similar weight loss to sleeve gastrectomy (around 70%-85%) initially, but gradually tailing off with time if post-operative instructions are not followed. It has the advantage over sleeve gastrectomy of not generally causing reflux and fixing it in those who have it. It is our preferred option in patients with severe reflux. The operative risk is similar to sleeve gastrectomy with leaks from the join between bowel and stomach (1%-2%) and post-operative bleeding (1%) being the most likely to cause an increase in hospital stay. Of course, the general risks of any surgical procedure, as already outlined in other documents also apply.

The normal hospital stay is 3-4 days. After discharge, please note the things that you need to IMMEDIATELY report to your surgeon if they occur as outlined in the College of Surgeons literature on the back page.

Long-term, gastric bypass has more problems than sleeve gastrectomy and it is not our preferred option in younger patients. These problems are:

1. Pouch and stomal dilatation which can lead to weight regain
2. Stomal ulcers (where the bowel joins the stomach). These cause pain, bleeding and sometimes perforation), or stomal stenosis (narrowing causing vomiting)
3. Bowel obstruction caused due to the creation of spaces by moving bowel around in the abdominal cavity to join it to the stomach
4. Dumping syndrome which may be early (osmotic effect) or late (hypoglycaemia)
5. Nutritional deficiencies (Vitamin D causing osteoporosis and increased risk of bone fracture), Fe deficiency and anaemia, protein malnutrition can all occur and supplements must be taken post operatively.
6. Persistent diarrhoea

As has been stated in other documentation weight loss surgery requires life-long follow-up and this also applies to gastric bypass surgery.

This document needs to be read in conjunction with the Royal Australasian College of Surgeons booklet on obesity surgery, and particular note needs to be made of post-operative symptoms you might experience after discharge about which you should contact your surgeon or go to the nearest Emergency Department. 

Please note your surgeons after hours Emergency number.