BMI
Patients with BMI < 30 will find the risks and adverse effects of bariatric surgery will outweight any medical benefits from the weight loss. The Orbera implantable balloon may be an option to consider.
BMI 30-35. These patients represent the grey area for the more invasive operations. The medical benefits conferred by the weight loss may not outweight the risks and adverse effects of the surgery. However quality of life and psychosocial issues may be significant and each case should be taken on its merits. The exception is injection dependent diabetics in whom bypass might be considered. Patients of asian background may qualify at lower BMIs as their propensity to develop metabolic diseases from obesity is higher.
Weight > 200kg. In this group sleeve may be best as bypass and SIPS surgery can be too difficult or dangerous. A second stage procedure once weight loss has occurred may be entertained
Blood thinners, NSAIDS and smoking
Orbera balloon should not be implanted in patients on blood thinners. NSAIDs and smoking increase the risk of ulcers occuring at the top join between stomach pouch and bowel (marginal ulcer) in gastric bypass surgery. Blood thinners can increase the risk of these ulcers bleeding.
Diabetes
Injecting diabetics may get a more profound response from gastric bypass or SIPS
Hypertension, Sleep Apnoea, Joint Pains
The more obesity related medical conditions and the more severe the condition, the more it is reasonable to look at the more powerful procedures (sleeve, bypass, SIPS) to achieve control of these conditions
Age factors
The extremes of suitable ages for weight loss surgery (e.g. early 20s, mid to late 60s) raise some difficult questions. There are no definitive answers however the more complex operations (e.g. bypass, SIPS) may be overkill for older groups as the long term benefits are unclear and complication rates may be higher. On the other hand, younger patients choosing sleeve or SIPS are taking on procedures with much less long term follow-up data available compared to bypass or banding for example
Previous Surgery
Most patients with previous bands or stomach stapling procedures are likely to be better off with gastric bypass as a revisional procedure. This procedure is relatively robust in terms of anatomical distortions from the previous surgery and adds a small malabsorption and hormonal component to the restrictive function. SIPS (loop duodenal switch) may be an elegant alternative for patients who have regained weight with sleeve, although bad refluxers should probably stick with the bypass. Those who have had bowel surgery before or similar will be more challenging to perform bypass or SIPS due to abdominal scar tissue and adhesions
Usual Bowel Habit
Many bariatric operations tend to reduce the frequency of bowel motions due to reduced intake. However SIPS surgery is usually associated with diarrhoea due to fat malabsorption. This could be a useful side effect for those who suffer long term chronic constipation