What is Bariatric Surgery?

What Is Metabolic and Bariatric Surgery?

Metabolic and bariatric surgery (MBS), or weight loss surgery, effectively treats severe obesity in adults, adolescents, and children. This surgery can improve the patient’s quality of life, can increase life expectancy, and may also help resolve conditions that are caused by obesity—including headaches, reflux, diabetes, liver disease, high blood pressure, joint pain, high cholesterol, asthma, and sleep apnea. After MBS, studies have shown that patients have lower blood sugar, blood pressure, and cholesterol levels, as well as decreased workload on the heart. They have improved health-related quality of life, and they live longer.

Our first approach to bariatric surgery, called the laparoscopic sleeve gastrectomy, is the most common procedure used worldwide in children with obesity. This type of surgery reduces the size of the stomach by removing the part of the stomach that produces ghrelin (a hunger hormone). It also causes increases in levels of the intestinal hormones GLP-1 and GIP (hormones that affect how a patient processes and stores energy), each time the patient eats food. This results in effective weight loss through both decreased intake and decreased storage of excess energy as fat. Our second approach, the laparoscopic Roux-en-Y gastric bypass, reduces the size of the stomach and reroutes the small intestine to create changes in intestinal hormones that lead to decreased hunger and weight loss. Rather than doing large-incision surgery, laparoscopic surgery uses specialized miniature instruments that are inserted through small incisions made in the abdominal wall. Sometimes we use the Robot to do the surgery, this offers a 3D view of the stomach as well as instruments with more flexibility.  Our team has been doing these types of MBS in children and adolescents since 2004.

In 2023, the American Academy of Pediatrics released a comprehensive 160-page document recommending treatment for children with obesity. In this report they supported the 2018 Pediatric Metabolic and Bariatric Surgery Guidelines by Pratt et al. published by the American Society for Metabolic and Bariatric Surgery. The ASMBS guidelines from 2018 recommend metabolic and bariatric surgery for adolescents with a body mass index (BMI) of 35 kg/m² or 120% of the 95th percentile, whichever is lower (with a co-morbidity), or a BMI of 40 kg/m² or 140% of the 95th percentile (whichever is lower), as severe obesity is associated with increased health risks. The guidelines emphasize that surgery should not be withheld for conditions like developmental delay or mental illness if the patient can adhere to postoperative care, and that early intervention is encouraged to prevent long-term end-organ damage. Further MBS in children and adolescents has been shown to improved quality of life, prolong life, lead to sustained weight loss at >15 years, and lead to sustained remission of associated conditions like type 2 diabetes, sleep apnea, fatty liver, high blood pressure, and other cardiometabolic risk factors.

Glucagon-like peptide -1 (GLP-1) medications and other anti-obesity medications (AOMs) were approved for use in children as young as 12, or even 6 for some syndromic obesity conditions, in 2022. Our program works with pediatricians in the community and at Stanford who are using these medications to treat childhood obesity. We recommend the use of surgery first for patients who meet BMI criteria for surgery and are unlikely to need AOMs in addition to surgery simply because of the cost, inconvenience, side effects, and lack of long-term data of AOMs. However, in patients with a BMI <120% of the 95th percentile or less than 140% of the 95th percentile without a comorbid condition, AOMs are a possible alternative to surgery. The Pediatric Weight Clinic physicians prescribe these medications and can provide comprehensive care for patients on AOMs.

In patients with a BMI over 55kg/m2 or 180% of the 95th percentile, we recommend AOMs and MBS (i.e., medications and surgery). This level of obesity can be very resistant to treatment and often requires significant intervention. In these cases, often surgery is preceded by treatment with one or more AOMs and followed by continuing AOMs. Finally, as an adolescent patient is reaching adulthood with persistent or resistant obesity, they may be offered more advanced, malabsorptive surgeries, like duodenal intestinal bypasses of various types. 

Laparoscopic sleeve gastrectomy

In a laparoscopic sleeve gastrectomy, surgeons remove a significant amount of the stomach, leaving a “sleeve”-shaped stomach. The surgery works in three main ways:

1. Given its reduced size, the stomach cannot hold as much food.
2. The procedure removes many of the cells that produce ghrelin, the hormone involved in creating the feeling of hunger.
3. The stomach empties its contents faster, causing the intestine to release GLP-1 and GIP, a hormone that makes you feel full and changes how your body stores the energy in the food you eat.

The laparoscopic sleeve gastrectomy provides advantages over other types of MBS. Patients are less likely to require further surgery for complications, it does not require the construction of new connections within the bowel, it has a lower risk of developing vitamin and mineral deficiencies, and the surgery can later be converted to another MBS if needed. Furthermore, adolescents who undergo laparoscopic sleeve gastrectomy have a similar total weight loss and reduction in obesity-related diseases after 10 years as adolescents who undergo a laparoscopic gastric bypass.  Female patients who go on to have children after sleeve gastrectomy are less likely to have children with obesity, to develop gestational diabetes or to end up with a C-section.  

Laparoscopic Roux-en-Y gastric bypass

Gastric bypass surgery changes the process of digestion. Like the laparoscopic sleeve gastrectomy, this operation decreases the size of the stomach. But it also causes significant changes in gut hormones like ghrelin, GLP-1, and others that result in decreased hunger, rapid feeling of fullness, and weight loss. After the surgery, food travels directly into the lower part of the small intestine, bypassing the first two sections of the small intestine. It therefore increases the risk of nutritional deficiencies. While the gastric bypass may have a higher complication rate, it also may result in greater long-term success from surgery in some patients with known genetic mutations or hypothalamic obesity. Gastric bypass may be the better choice in some adolescents and children with severe obesity.