One Anastomosis Gastric Bypass and Mini Gastric Bypass (Gastric Bypass)

Overview of One Anastomosis Gastric Bypass and Mini Gastric Bypass

Obesity, or being severely overweight, is a serious issue affecting people of all ages and backgrounds worldwide. It can cause a whole range of other health problems like heart disease, type 2 diabetes, certain types of cancer, mental health challenges like depression and anxiety, and more. Treating obesity usually needs a combination of lifestyle changes, improved eating habits, therapy to change behaviour, medication, and sometimes even surgery.

One of the ways that doctors figure out how overweight a person is, is by calculating something known as Body Mass Index (BMI). The higher the BMI, the more overweight the person is. Bariatric surgery, which is surgery that helps with weight loss, has been found to be very effective for people falling into Class I, II and III obesity categories. These categories are determined by your BMI (30-34.9 kg/m² for Class I, 35-39.9 kg/m² for Class II, and 40 kg/m² or more for Class III). For people of Asian descent, these criteria might be a bit lower, due to health risks associated with lower levels of BMI.

Bariatric surgeries come in three types. The first type, called restrictive procedures, limit how much food your stomach can hold, so you end up eating less and consuming fewer calories. The second type is called malabsorptive procedures, these change the way your gut processes food, making it absorb less nutrients. But they can lead to nutritional deficiencies if not managed properly. The third type, combined procedures, makes use of both restriction and malabsorption techniques. Examples of these combined procedures are Roux-en-Y gastric bypass (RYGB), biliopancreatic diversion/duodenal switch (BPD/DS), and one anastomosis gastric bypass/mini gastric bypass (OAGB/MGB). These surgeries not only help with substantial weight loss, but also improve overall metabolic health.

The OAGB/MGB is a certain type of combined bariatric surgery and was introduced by Dr. Robert Rutledge in 1997. This surgery involves creating a small pouch in the stomach and connecting it to a loop in the small intestine. It’s a more simple method than the traditional RYGB surgery, which has two connecting points. Recent modifications to the OAGB/MGB surgery, like those developed by Dr Miguel Carbajo, aim to reduce a side effect known as bile reflux, or backward flow of bile.

Anatomy and Physiology of One Anastomosis Gastric Bypass and Mini Gastric Bypass

The stomach is found in the upper part of your tummy, sitting underneath the diaphragm muscle, and to the left of the center of your abdomen. It’s sort of like a food processing plant, settled between the esophagus (food pipe) and the duodenum, which is the start of the small intestine. As food moves through the stomach, it’s broken down in different sections including:

• The cardia, which is the entrance for food coming from the esophagus into the stomach.
• The fundus region, a dome-shaped area above and to the left of the cardia where gas produced during digestion is collected.
• The body, which is the largest part of the stomach connecting to the fundus and helps in breaking down food further.
• The antrum is the lower part of the stomach that collects digested food until it’s ready to move into the small intestine.
• The pylorus is the funnel-shaped region at the end of the stomach, leading the food into the duodenum of the small intestine. It has a muscular ‘valve’ controlling the release of partially digested food also known as chyme.

The stomach has a unique shape with curves that doctors call the lesser and greater curvature. At the back of the stomach, there’s a small cavity called the lesser sac. This is a space in front of the pancreas and is surrounded by several organs and structures such as the spleen, left kidney, and transverse mesocolon.

The stomach is made up of five layers:

• The mucosa is the inner lining where most stomach cancers originate. This layer itself has small compartments made up of different types of cells: cells that produce mucus to protect the stomach from its own acid, cells that make acid to aid digestion, and others that release hormones to control digestion.
• The lamina propria, a layer of tissue underneath the mucosa.
• The muscularis mucosa, a thin layer of muscle beneath the lamina propria.
• The submucosa, a supporting layer right beneath the mucosa.
• The muscularis propria, a thick muscle layer that helps move and mix the stomach’s contents.
• The serosa, the outermost wrapping layer of the stomach.

The stomach has its own blood supply coming from:

• The celiac trunk: a major artery supplying the abdomen.
• The left gastric artery: supplies the upper part of the lesser curvature of the stomach.
• The right gastric artery: supplies the lower part of the lesser curvature of the stomach.

The veins draining the blood from the stomach usually have the same names as the arteries supplying them.

Additionally, the stomach is anchored in place by different ligaments and is also innervated with both sympathetic and parasympathetic nerves, which means it’s connected to our nervous system. This allows the nerves to control and regulate the functions of the stomach, including the secretion of gastric juices necessary for digestion and the rhythmic contraction and relaxation movements that help in moving and mixing the food contents.

Why do People Need One Anastomosis Gastric Bypass and Mini Gastric Bypass

Bariatric surgery, or weight loss surgery, is advised for people dealing with early, moderate, and severe obesity (referred to as Class I, II, and III) when traditional ways to lose weight such as dieting, exercise, and medication have not worked. A team-based approach, involving dietitians, therapists, doctors, and surgeons, is crucial in assessing a person’s suitability for this kind of surgery and also helps in taking comprehensive care of the patient before and after the surgery.

Weight loss surgery is also becoming more common to help prepare patients for other procedures like transplants and surgeries related to the heart, joints and hernias. These recommendations are based on the latest guidelines by the American Society for Metabolic and Bariatric Surgery, and the International Federation for the Surgery of Obesity and Metabolic Disorders.

Here’s what the guidelines say:

For obesity:

* Bariatric surgery is suggested for people with a body mass index (BMI – a measure of body fat) of over 35 kg/m2. Comorbidities—simultaneous chronic diseases or conditions—are not necessarily factors, and people with type 2 diabetes and a BMI over 30 kg/m2 might be candidates for surgery too.
* The surgery can be considered for people with a BMI between 30 to 34.9 kg/m2 who haven’t seen meaningful weight loss or any improvement in other health conditions with non-surgical treatments like adjusting their diet and lifestyle, therapy or taking medication.
* It’s important to note that people of Asian heritage might qualify for surgery at lower BMI benchmarks.

For obesity-related additional medical conditions:

* Type 2 diabetes: Bariatric surgery can cause major improvements or even recovery in obese individuals with this condition.
* High blood pressure: The surgery can vastly reduce blood pressure levels in obese individuals.
* Dyslipidemia: This refers to abnormal amounts of lipids (fats or cholesterol) in the blood. Bariatric surgery can improve these conditions, including reducing total cholesterol, harmful (low-density) cholesterol, and triglyceride levels.
* Sleep apnea: The surgery might relieve or resolve symptoms of sleep apnea such as snoring, feeling sleepy during the day, and apnea-hypopnea index scores (which estimate the severity of sleep apnea).
* Acid reflux: The surgery might improve acid reflux by lowering the production of stomach acid and aiding weight loss.
* Cardiovascular disease: This includes heart conditions like coronary artery disease, heart failure, and atrial fibrillation.
* Steatotic liver disease: This includes conditions like metabolic dysfunction-associated fatty liver disease (MASLD, previously called non-alcoholic liver disease or NAFLD) and metabolic dysfunction-associated steatohepatitis (MASH, previously non-alcoholic steatohepatitis or NASH).
* Asthma
* Chronic kidney disease
* Polycystic ovary syndrome
* Infertility
* Diseases affecting the bones and joints

Other considerations:

Patients should get clearance from their healthcare provider, indicating that they are in a good condition overall to handle both the anesthesia and the surgery.

It is also important that patients have a psychological evaluation to assess their readiness for the surgery and see if they can stick to the necessary changes in their diet and lifestyle after the operation. This can also help flag any potential psychological challenges post-surgery.

When a Person Should Avoid One Anastomosis Gastric Bypass and Mini Gastric Bypass

The OAGB/MGB procedure, a type of weight loss surgery, is known for being highly effective in helping with weight reduction and improving metabolic issues. However, like any medical procedure, it involves certain risks and potential complications. These must be taken into consideration before and after the surgery. These are sorted into three categories.

Absolute contraindications are conditions where the surgery cannot take place:

• If a patient’s surgical risk is too high. For example, if the part of their heart that pumps blood (left ventricular ejection fraction) is functioning less than 10% of its capacity.
• If a patient has severe liver disease that is worsening (decompensated liver cirrhosis).
• If a patient has mental health conditions or eating disorders that are not being managed or treated effectively.
• If a patient is currently struggling with drug dependency.

Relative contraindications are conditions where the surgery may be more risky but can still be carried out with additional caution:

• If a patient has issues with healing wounds.
• If a patient is a current smoker.
• If a patient uses steroid or non-steroid anti-inflammatory drugs regularly over a long period of time.

Here are the specific contraindications for the OAGB/MGB procedure, meaning conditions under which this specific type of surgery should not be performed:

• If a patient has a short gut syndrome, either primary (total small intestine length is less than 350 cm) or secondary (after a resection, a surgical process used to remove some or all of an organ).
• If a patient has been diagnosed with Crohn’s disease, a type of inflammatory bowel disease.

Equipment used for One Anastomosis Gastric Bypass and Mini Gastric Bypass

When a surgeon performs an OAGB/MGB surgery, which is a type of weight loss procedure, they usually have a range of tools they prefer to use. However, certain pieces of equipment are typically necessary for the operation:

The surgeon needs a laparoscopic tower, which is like a control hub complete with a high-resolution camera, a light source and a system to inflate your belly with gas, making it easier to see and work.

They use a Nathanson liver retractor, a tool to gently move the liver out of the way during the procedure.

Trocars are also needed; these are tubes inserted through small cuts on your belly that the surgeon uses to pass surgical instruments into your body. Generally, surgeons use both 5-mm and 12-mm ones.

Laparoscopic staplers and energy devices are also used, which essentially help cut and seal tissues inside the body. Suturing tools or tools for stitching after the operation are also required.

For sizing purposes, a nasogastric tube and bougie, which is a thin and flexible surgical instrument, is used.

The surgeon uses hemoclips or stapling reinforcements to manage bleeding and to achieve a secure closure of any incisions made.

Suction and irrigation is another essential element to keep the area clean and clear by removing excess fluids or gases.

Bariatric surgical tools also come in longer lengths to work with larger abdominal cavities often found in patients with obesity. These tools include laparoscopic scissors, graspers that pick up or hold tissues, retractors which hold back tissues or organs, and dissectors which carefully separate tissues.

Who is needed to perform One Anastomosis Gastric Bypass and Mini Gastric Bypass?

An OAGB/MGB operation, also known as a type of weight loss surgery, is carried out by a team of medical professionals. The team includes:

The Surgical Team:

• A Surgeon, who is a specifically trained doctor that performs the operation. The surgeon could stand either on the patient’s right side or between their legs.
• A Camera Assistant, who helps the surgeon by controlling the camera during the surgery. They might stand on either side of the patient.
• A Surgical Technician or an Operating Room Nurse, who assists in the surgery. They usually stand on the left side of the patient.

The Anesthesia Team:

• An Anesthesiologist, a doctor who specializes in giving medicines that make sure you don’t feel pain or discomfort during the surgery.
• An Anesthesia Assistant, who helps the anesthesiologist.

The Operating Room Staff:

• A Circulating or Operating Room Nurse, who helps make sure everything runs smoothly in the operating room.

Each one of these professionals has a specific role often trained for a number of years. Their aim is to make sure your operation is safe and successful.

Preparing for One Anastomosis Gastric Bypass and Mini Gastric Bypass

Before having an OAGB/MGB – a type of weight loss surgery – there are important steps that patients need to take to make sure the operation goes well and is as safe as possible. These steps generally fall into three categories: dietary restrictions, medication management, and a comprehensive pre-surgery evaluation.

Dietary Restrictions

Patients are typically asked not to eat or drink anything for a period of time before the surgery. This is done to lower the risk of problems during the operation and help the recovery process go smoother. Some places may even recommend a diet of only clear liquids for 7 to 10 days before surgery. The purpose of this diet is to help shrink the liver. This is particularly useful for overweight patients because it gives the doctors a better view of, and access to, the stomach during the procedure.

Medication Management

It’s really important for a team of health professionals – including surgeons, anesthesiologists, and the patient’s primary care doctor – to carefully manage the patient’s medications leading up to the surgery. Medicines that thin the blood may need to be temporarily stopped or adjusted to lower the risk of bleeding during the operation. Other medications may need to continue being taken or might need to be modified based on what the patient needs.

Preoperative Evaluation

A comprehensive evaluation before surgery is also crucial. This might include a series of tests to check the structure of the esophagus, stomach, and duodenum (the first part of the small intestine), making sure there are no conditions that could make the surgery more complicated. It’s especially important to identify and treat an infection from a bacteria called Helicobacter pylori before surgery, as untreated infections can lead to ulcers after the surgery. Getting rid of the infection lowers this risk and leads to better long-term results.

How is One Anastomosis Gastric Bypass and Mini Gastric Bypass performed

The One Anastomosis Gastric Bypass/Mini Gastric Bypass (OAGB/MGB) is a weight loss surgery technique that has been practiced since 1997. This technique involves a two-step process. First, the stomach is divided into a smaller pouch. Secondly, the smaller pouch is then connected to the lower part of the small intestines (jejunum). The design of the pouch is to ensure food passes easily from the start of the small intestine to the end. This changes the way the stomach empties into the intestine and can cause the person to feel uncomfortable when they consume sweet or fatty foods. It essentially guides the patient to eat smaller, low-fat, and low-sugar meals.

The OAGB/MGB procedure is built on two primary ideas: making a smaller stomach pouch (the restrictive part) and bypassing the upper part of the small intestine (the malabsorptive part). It’s worth noting that this procedure is called by different names in different clinical settings. There can also be slight modifications to the surgical technique depending on the surgeon and the hospital. Commonly, the name OAGB/MGB refers to a long narrow tube generated from the lesser curve of the stomach to the small intestine.

Let’s break down the operation technique:

1. After general anesthesia, the patient is placed on the operating table. Various measures are taken to avoid complications like blood clot formation in the legs.
2. To begin the procedure, five surgical instruments are placed in the abdomen through small incisions in the skin.
3. Once in the abdomen, the surgical team checks the intestines, liver, and other belly areas for abnormalities. The liver is lifted to get a better view of the surgery site.
4. Next, the surgeon starts making the stomach pouch using a linear decoration.
5. Once the pouch is done, a cut is made on the stomach pouch, and the small intestine areas for connection are decided.
6. The pouch is then connected to the small intestine. Any bleeding in the area is immediately controlled.
7. After this, the connection is closed using stitches that get absorbed in the body naturally.
8. The final steps involve testing the surgery for leaks. If there are no bubbles when an endoscope is passed through the connection, it confirms that the surgery is watertight. Sometimes, a blue dye is used for this test.
9. Finally, the surgical instruments are removed, and the incisions are closed.

After the operation, the patient can often start with clear fluids from the very next day. Most patients are able to tolerate this well, and they may not need a special test to check the surgical site unless it’s needed based on clinical conditions.

Possible Complications of One Anastomosis Gastric Bypass and Mini Gastric Bypass

One-gastric bypass (OAGB/MGB) is viewed as a safe and effective weight-loss surgery. However, like all surgeries, it may come with a few complications which can happen shortly after the surgery or come about much later.

Early complications of OAGB/MGB can include leakage at the surgical connection point, bleeding, blockages in the bowels, and serious clotting in the veins that can travel to the lungs. A leak, although rare, can be life-threatening and typically appears about 1 to 3 days after surgery. On the other hand, bleeding might need a blood transfusion to correct, and bowel obstruction might be due to surgical mistakes.

Late complications may include internal hernias, ulcers at the margin of the surgical connection, too-narrow surgical connection points, abnormal connections between two parts of the stomach, nutrient deficiencies, gallstone formation, and a disorder called dumping syndrome. An internal hernia might cut off blood supply to the intestine and might have to be fixed with another surgery. Strictures might block the passage of food and might need a special procedure or another surgery for correction.

Patients who have had OAGB/MGB might also need to take vitamins and minerals for life because of the risk of nutrient deficiencies due to malabsorption. Gallstones are common due to rapid weight loss and might need their careful management, including a procedure called laparoscopic cholecystectomy. Dumping syndrome is a condition with different symptoms that might occur after a meal, especially after eating foods rich in sugars or fats. The symptoms can include nausea, vomiting, stomach cramping, diarrhea, dizziness and feeling light-headed. This condition might require changes in diet and behavior.

What Else Should I Know About One Anastomosis Gastric Bypass and Mini Gastric Bypass?

OAGB/MGB is a type of weight loss surgery that’s gaining recognition as a powerful method to manage obesity and related health conditions. Studies show that this surgery is very effective, with patients usually losing between 60% to 80% of their excess body weight within a year to two years after the operation. One study found that this level of weight loss continued for five years, proving that OAGB/MGB is helpful for long-term weight management.

There’s also good news for people with certain health problems linked to obesity. Many patients saw their Type 2 Diabetes (T2DM) disappear: about 80% did not need their diabetes medication anymore after OAGB/MGB. The surgery also reduced high blood pressure in 65% of patients and improved high cholesterol levels in over 70% of cases. These changes demonstrate the procedure’s effectiveness in tackling the many health conditions associated with obesity.

Additionally, OAGB/MGB influences hormonal regulation related to appetite control. These hormonal changes seem to reduce appetite, increase feelings of fullness, and improve sugar metabolism, all of which support weight loss and healthier metabolism. The hormones affected include ghrelin, cholecystokinin, GLP-1, PYY, and amylin, but more research is necessary to understand these mechanisms fully.

When compared to another type of weiht-loss surgery known as RYGB, OAGB/MGB seems to offer similar or even better results in terms of weight loss and improvement in metabolism. One study found that people who underwent OAGB/MGB lost just a bit more excess weight and a slightly higher percentage were able to stop their diabetes medication compared to those who underwent RYGB.

OAGB/MGB seems to have a slightly lower risk of complications and takes less time than RYGB. It takes on average, about 85 minutes compared to RYGB’s 120 minutes, and the risk of complications like leaks where connections (anastomoses) are made during surgery is less than in RYGB. The simpler nature of the OAGB/MGB procedure, which involves creating fewer connections within the stomach, potentially adds to its safety and a lower chance of other complications like internal hernias (a condition in which the intestine bulges through a weak spot in the abdominal wall). These findings highlight the clinical significance of OAGB/MGB as a safe and effective weight-loss surgery that provides strong weight loss, significant metabolism improvements, and a favorable risk profile compared to other similar surgeries.