PB  Productive burp
A commonly reported occurrence for banded patients is regurgitation of non-acidic swallowed food from the upper pouch, commonly known as Productive Burping (PBing).

Productive Burping is not to be considered normal. The patient should consider eating less, eating more slowly, or chewing their food more thoroughly. Occasionally, the narrow passage into the larger / lower part of the stomach may become blocked by a large portion of unchewed or unsuitable foodstuff.

RNY  Roux en Y Gastric Bypass
The gastric bypass procedure consists in essence of the creation of a small, (15-30 mL/1-2 tbsp) thumb-sized pouch from the upper stomach, accompanied by bypass of the remaining stomach (about 400 mL and variable). This restricts the volume of food which can be eaten. The stomach may simply be partitioned (typically by the use of surgical staples), or it may be totally divided into two parts (also with staplers). Total division is usually advocated, to reduce the possibility that the two parts of the stomach will heal back together, negating the operation. 

The GI tract is then reconstructed to enable drainage of both segments of the stomach. The technique of this reconstruction produces several variants of the operation, which differ in the lengths of small bowel used, the degree to which food absorption is affected, and the likelihood of adverse nutritional effects. 

DS Duodenal Switch
Stage 1 - Restrictive
Approximately 70% of the stomach is removed (partial gastrectomy) along the greater curvature (also called vertical sleeve gastrectomy (VSG). The remaining stomach is fully functioning, banana shaped and about 3 - 5 oz in size, restricting the amount a person can eat. The pylorus remains in use controlling the emptying the stomach. As a result patients do not experience "dumping". The upper portion of the duodenum is also in use; food is able to digest to an absorbable consistency in the stomach before moving into the small intestine. This allows for better absorption of nutrients like vitamin B12, calcium, iron and protein when compared to other gastric bypass procedures. 

A benefit of removing a portion of the stomach is that it also greatly reduces the amount of ghrelin producing tissue and the amount of acid. Ghrelin is the "hunger hormone" and reducing the amount produced suppresses the appetite.

The stomach will stretch over time; 9-12 months post-op it will eventually double in size and patients will be able to eat approximately 60% of what they ate before surgery. This is why the malabsorbtive component of the surgery is so important for maintaining long term weight loss.

The restrictive component of the Duodenal Switch procedure is not reversible.

Stage 2 - Malabsorptive
The intestines are switched so that food from the stomach and digestive juices travel separate paths and don't mix until they meet up towards the end of the small intestine, instead of at the beginning. The digestive limb carries the food. The bilio-pancreatic limb carries the bile and digestive juices. The common channel, also known as the common tract or common limb, is the point from where these two limbs meet in the small intestine to where they move into the large intestine. The common channel is where a DS patient's food, bile and digestive juices mix and nutrients are absorbed. Since the common channel makes up such a small portion of the small intestine dietary starches, fats and complex carbohydrates are not fully absorbed. As a result DS patients' only absorb 20% of fats, 60% of protein, 60% of complex carbohydrates and 100% of simple carbohydrates. This is why DS patients require double the protein requirement of a normal person. The inability to absorb fats also interferes with absorption of the fat-soluble vitamins A, D, E & K but it also lowers your cholesterol and triglycerides. As a result all Duodenal Switch patients are required to take vitamins and calcium supplements for life. Patients who are diligent with the required supplements and have their blood work monitored maintain normal levels.

Adjustable Gastric Banding
The placement of the band causes the creation of a small pouch at the top of the stomach that holds approximately 4 oz to 8 oz of food each meal. This pouch fills with food quickly and the band slows the passage of food from the pouch to the lower part of the stomach. As the upper part of the stomach registers as full, the message to the brain is that the entire stomach is full and this sensation helps the person to be hungry less often, to feel full more quickly, to eat smaller portions, and lose weight over time.
The band is inflated/adjusted via a small access port placed just under the skin.

Dumping Syndrome
Dumping syndrome, or rapid gastric emptying, is a combination of symptoms that occur when an overly large meal, or a meal high in fat or sugar is consumed by a weight loss surgery patient. The meal is "dumped" into the small intestine when the stomach empties quickly, causing feelings of nausea, vomiting, diarrhoea, stomach gas, racing heart, cramps and cold sweats. 

Most episodes of dumping syndrome can be prevented by avoiding eating overly large meals and sugary foods. Prevention is important as the symptoms are not only very uncomfortable, but they also are very similar to the symptoms of a heart attack.

Restriction
Restriction is a feature of all the weight loss surgery procedures.  The amount of food that can be eaten with comfort by the patient is greatly reduced.  For the RNY and the DS this is done surgically.  For those who are banded restriction will come when the band is filled to a level suitable for each patient.  

Malabsorption
Malabsorption is a state arising from abnormality in digestion or absorption of food nutrients across the gastrointestinal(GI) tract.  Malabsorption constitutes the pathological interference with the normal physiological sequence of digestion (intraluminal process), absorption (mucosal process) and transport (postmucosal events) of nutrients.
As noted RNY has an element of malabsorption and the DS is much more a malabsorptive surgery.

EWL = Excess Weight Loss 
This is measured as a % of the total weight you need to lose to reach a normal BMI.  It is calculated by dividing the amount of weight lost to date by the total amount of weight that needs to be lost to give a normal BMI, multiplied by 100.

There are many calculators available on the internet to calculate your excess weight loss.

BPD Biliopancreatic Diversion
This complex operation is also known as biliopancreatic diversion (BPD), or Scopinaro procedure. This surgery is now rare because of problems with malnourishment. It has been replaced with the Duodenal Switch also known as the BPD/DS. Part of the stomach is resected, creating a smaller stomach (however after a few months the patient can eat a completely free diet as there is no restrictive component). The distal part of the small intestine is then connected to the pouch, bypassing the duodenum and jejunum. This results in around 2% of patients severe malabsorption and nutritional deficiency that requires restoration on the normal absorption.

Midband
MIDBAND™ is the brand name of an adjustable gastric band.  It is a low pressure silicone band that is placed around the outside of the stomach by minimally invasive surgery (keyhole surgery).
Made up of 3 component parts:
1 An inflatable band 
2 Small titanium reservoir (or port) 
3 A narrow silicone tube (catheter) linking the port to the band. 

Fills for Gastric Band 
X-Ray Fill
Correct and sensitive adjustment of the band is imperative for weight loss and the long term success of the procedure. Adjustments (also called "fills") may be performed using an X-ray fluoroscope so that the radiologist may assess the placement of the band, the port and the tubing that runs between the port and the band. The patient is given a small cup of liquid that contains a radio-opaque fluid similar to barium-clear or white. When swallowed, the fluid is clearly shown on X-ray and is watched as it travels down the esophagus and through the restriction caused by the band. The radiologist is then able to see the level of restriction in the band and to assess if there are potential or developing issues of concern. 

Non X-Ray Fill
Some health practitioners adjust the band without the use of X-ray control (fluoroscopy). In these cases, patients visiting for a regular fill adjustment will typically find they will spend more time talking about the adjustment and their progress than the actual fill itself, which generally will only take about one to two minutes.

Defill
Reflux type symptoms may indicate too great a restriction and further investigation may be required. In some circumstances fluid is removed from the band prior to further investigation and re-evaluation. In some cases further surgery may be required (e.g. removal of the band) should gastric erosion or similar be detected.

Body Mass Index (BMI)
The most widely used measurement for obesity. The BMI approximates body mass using a mathematical ratio of weight and height [kg/m2 (or lbs/inches2 * 704.5)]. 
A BMI of 18-25 is the medially healthy range.  A BMI of 30 or more is regarded by most health agencies as the threshold for obesity. A BMI of 40 or more qualifies as morbid obesity. However, note that the BMI measurement in bodybuilders and athletes may not be accurate determinants of obesity because the BMI does not distinguish between muscle and fat.