Bariatric Surgery And Diabetes Remission.

What Is Bariatric Surgery?

The term bariatric surgery is an umbrella term for gastric bypass and other weight-loss surgeries done to assist patients with severe obesity. It is done when excess weight is causing serious health problems like type 2 diabetes, high blood pressure, etc., and the traditional methods to reduce obesity have become ineffective.

Some procedures work by reducing the amount of food consumed by the patient, and a few others decrease the body’s ability to absorb nutrients. The bariatric surgeon will review the patient's health history and determine the suitable surgery.

Who Is Eligible for a Bariatric Procedure?

Although it is an elective procedure, not everyone who is overweight needs or can get the procedure done. The criteria for the patient to be a candidate for any bariatric surgery are-

• Body mass index greater than 40 even though there are no obesity-related comorbid conditions like diabetes, hypertension, sleep apnea, etc.

• Body mass index equal to or more than 35 and at least one obesity-related comorbid condition.

• Unsuccessful non-operative weight loss attempts.

• Mental health clearance.

• No medical contraindications to surgery.

What Are the Different Types of Bariatric Surgeries?

The procedures approved by the American Society for Metabolic and Bariatric Surgery (ASMBS) are mentioned below-

Sleeve Gastrectomy- The stomach is a ‘J’ shaped structure with an inner lesser curvature and an outer greater curvature. After anesthesia, the surgeon will dissect almost 80 % of the outer greater curvature, leaving the stomach in the shape and size of a banana that will hold less food and liquids, thereby reducing the amount of food consumed.

The remaining stomach also does not produce the “hunger hormone,” also known as ghrelin; this decreases hunger, increases fullness, and controls blood sugar levels. As time progresses, the body will adjust itself to the changes and maintain a healthy weight.

The advantages of this procedure are-

1. Shorter surgery time and less technique sensitivity.

2. Also can be performed on patients with high-risk medical conditions.

3. This procedure leaves room for other surgeries; if the expected result is not achieved, the surgeon can always go ahead with gastric bypass or other bariatric surgeries.

4. It reduces the extra weight and improves associated medical conditions effectively.

The disadvantages of the procedure are-

1. It is an irreversible procedure.

2. It will cause or worsen acid reflux and heartburn.

3. Compared to other bariatric procedures, it has less impact on metabolism.

Roux-en-Y Gastric Bypass (RYBG)- One of the most commonly performed procedures to reduce obesity and its related complications. The procedure needs two dissections- one is done horizontally to divide the stomach into a smaller upper pouch and the lower stomach.

The second dissection is done in the small intestine; these two dissections will divide the entire digestive tract into three parts-

1. The first part contains the pharynx, esophagus, and pouch (part of the stomach).

2. The second part contains the major stomach and the first section of the small intestine.

3. The third part contains the remaining small intestine, large intestine, rectum, and anus.

Now, the third part is sewn directly onto the pouch of the first part; this creates a new digestive tract. The food will pass through from the esophagus into the pouch, then into the small intestine, the rectum, and then the anus, thereby bypassing the second part.

The second part is sewn into the large intestine, which facilitates the drainage of the gastric juices secreted by the stomach and the first section of the small intestine.

These criss-cross attachments resemble the shape “Y,” hence the name.

The advantages of this procedure are-

1. Reliable and long-lasting weight loss.

2. Effective for the remission of obesity-associated conditions.

3. Refined and standardized technique.

The disadvantages of the procedure are-

1. High risk of small bowel obstruction.

2. Highly technique sensitive.

3. It will cause nutritional deficiency.

4. Occasionally leads to dumping syndrome (feeling sick immediately after eating).

5. High risk of developing ulcers.

Adjustable Gastric Band (AGB) - Relatively simple procedure when compared to other bariatric surgeries, the surgeon will wrap a silicone device in the top part of the stomach creating a small pouch above the band.

The band will squeeze and reduce the opening between the pouch and the rest of the stomach, so whenever the patient consumes food and liquids, the pouch will fill up faster and create the sensation of being full. This will limit the patient’s intake and, in the long run, will reduce the excess weight.

Food will pass down to the rest of the stomach but slowly and in very less quantity than it is used to.

The advantages of this procedure are-

1. The lowest rate of complications post-surgery.

2. No division of stomach or intestines.

3. It can be done as an outpatient procedure.

4. The band can be removed if needed.

5. Has the lowest risk for nutritional deficiency.

The disadvantages of the procedure are-

1. The band will need several adjustments during the first year of the procedure.

2. Slower and less effective weight loss when compared to other procedures.

3. Higher risk of slippage of the band and damage to the stomach due to erosion.

4. Requires a foreign implant to remain in the body.

5. Has a high rate of reoperation.

6. It can cause enlargement in the esophagus and difficulty in swallowing.

Biliopancreatic Diversion With Duodenal Switch - It is a two-part procedure-

1. In the first part, the surgeon will reduce the size of the stomach, similar to a sleeve gastrectomy.

2. The second part is similar to a gastric bypass. It is designed to eliminate the jejunum and ileum (both are parts of the small intestine where nutrient absorption is at its peak).

Two incisions are made- One below the duodenum (first part of the small intestine) and the second one in the lower end of the small intestine. These incisions will separate the jejunum and most of the ileum. The surgeon will join the duodenum with the lower ileum of the small intestine.

Now the food will pass through the reduced stomach, the duodenum, and the lower part of the ileum and then into the large intestine.

The dissected small intestine that contains the jejunum and ileum is not removed from the body; it is joined back at the end of the small intestine.

The advantages of this procedure are-

1. Has the best results in improving obesity.

2. Affects bowel hormones to cause less hunger and more fullness after eating.

3. It is the most effective treatment to treat type 2 diabetes.

The disadvantages are-

1. Has more complications than other procedures.

2. Nutrition deficiency.

3. Worsens acid reflux and heartburn.

4. Highly technique sensitive.

How Does Bariatric Surgery Cure Diabetes?

Bariatric surgery has been shown to significantly improve type 2 diabetes when compared to alternatives like pharmacotherapy and lifestyle changes. Type 2 diabetes is caused due to a combination of low amounts of insulin production from the pancreas and peripheral insulin resistance. Insulin resistance is when the cells in the muscles, fat, and liver do not respond well to insulin and cannot take up glucose easily.

This is reversed after bariatric surgery; it creates an acute negative calorie deficit- patients who underwent bariatric surgery will consume fewer calories than their body required to stay at their current weight.

This sudden negative balance normalizes plasma glucose levels within days; the long-term changes are as follows-

• Calorie restriction in the early postoperative period decreases the fat content which was previously stored in the liver. Now that the liver has used up its stored energy source, it will have to take up glucose from the blood with the help of insulin to meet the energy demands of the entire body. As a result, the hepatic insulin sensitivity is reduced, followed by improvement in peripheral insulin sensitivity (observed only in RYGB).

• Lack of enough food in the stomach also inhibits hormones like ghrelin, incretin, cholecystokinin, etc., which promote the production of glucagon (a hormone that increases blood glucose levels in the body).

• The insulin insufficiency that was present before the surgery is no longer present after surgery due to the reduced food intake. The amount of insulin produced by the pancreas will be sufficient to maintain the blood glucose level.

• Other changes include improved gut bacteria, altered bile acid metabolism, and increased peptide tyrosine, all of which reduce hepatic and peripheral insulin sensitivity leading to the healthy maintenance of blood glucose levels and eventually to diabetes remission.

Conclusion-

Bariatric surgery is an elective procedure that provides weight loss, but the amount of weight that can be reduced depends on the type of surgery and the altered lifestyle changes that the patient is supposed to maintain post-surgery. The procedure itself has many complications and risk factors and is only performed by the bariatric surgeon when the benefits outweigh the drawbacks. Long-term is necessary for the success of the procedure and to improve the quality of patients’ life.