At Boston Medical Center, we offer three types of weight loss surgery, the gastric bypass, the adjustable gastric band and the vertical sleeve gastrectomy. All three procedures limit the amount of food you can eat, and result in excellent weight loss. The surgeries are commonly performed laparoscopically. There are some important differences that must be considered when you and your surgeon are deciding on the best procedure for you.
This is a diagram of the gastric bypass procedure. Your stomach will be made smaller by stapling and dividing it into two compartments. The smaller compartment is called a pouch. The larger part of the stomach is bypassed, meaning that the food is going around it, rather than passing through it. A small opening called an outlet is made in the newly formed pouch and is connected to a limb of intestine. The food will pass directly from the pouch into the intestine, but it will take several hours for the pouch to empty because the outlet opening is small making you feel full longer. Also because the pouch holds about 2 ounces of food, you will eat less food at one time – this will help you lose weight. You will eat smaller quantities of food and you will feel full very quickly. Because the limb of intestine used to empty your stomach will bypass the upper part of your intestines, it will reduce the absorption of food, which will also help you to reduce and control your weight. You will need vitamin and mineral replacements because the main stomach and the first part of the small intestine are bypassed.
As you begin to eat and take medication, remember that everything passing through the stomach must be small enough to fit through the opening of the outlet. As a guideline, food should be able to pass through a straw, which is why you are placed on a special liquid diet immediately following surgery. The goal is to let the stomach heal; only liquids and soft solids should be eaten during the first two months. Since many pills are quite large and will not fit through the outlet, we ask you to crush all medications or take them in liquid or chewable form. You will receive written instructions on the proper diet to follow from your dietitian. The food will pass directly from the pouch into the intestine, but it will take several hours for the pouch to empty because the outlet opening is small making you feel full longer. Also because the pouch holds about 2 ounces of food, you will eat less food at one time – this will help you lose weight. You will eat smaller quantities of food and you will feel full very quickly. Because the limb of intestine used to empty your stomach will bypass the upper part of your intestines, it will reduce the absorption of food, which will also help you to reduce and control your weight. You will need vitamin and mineral replacements because the main stomach and the first part of the small intestine are bypassed.
It is very important that you do not overeat, especially during the first two months following the surgery when the stomach is healing. If you eat more than your stomach can hold, you risk vomiting. Remember, the stomach is very delicate.
You also need to know about dumping syndrome, a side effect of the operation. Dumping syndrome might include one or all of the following symptoms: light-headedness, dizziness, heart palpitations, sweating, nausea, cramps, and/or diarrhea. This condition is the result of eating the wrong food, overeating, or drinking with or too soon after eating meals. The food enters the intestines quickly and causes it to distend, producing some or all of the symptoms mentioned above. Highly concentrated foods such as sweets and high-fat foods can cause dumping, so these foods should be avoided. Your dietitian will review with you substitutions for these foods.
Adjustable Gastric Band or Lap Band
This is a diagram of the adjustable gastric band. A soft plastic band is placed at the top of your stomach, dividing the stomach into two compartments. The small portion of stomach above the band is called the pouch. The outlet or stoma is created by placing the band around the upper part of your stomach. The band is adjustable as it can be filled with saline to alter the size of the outlet between the two parts of the stomach. The size of the outlet helps control the passage of food from the pouch to the main stomach. As the outlet is made smaller by filling the band, you will feel full sooner and have a feeling of satiety. Because the stomach and intestines are not rerouted, food will still travel through all parts of your digestive tract. Because of this, there is less chance for nutritional deficiencies.
Immediately after the surgery, the band will not be filled. However, due to swelling at the surgical site, you will feel some restriction. The outlet between the pouch and the main stomach will be very small. Because of this, we will maintain you on a high-protein liquid and soft-solid diet during the first two weeks after surgery. As you begin to take medications, remember that they must be small enough to pass through the outlet. We will ask you to crush your pills, or take them in a chewable or liquid form. It is very important not to overeat early after surgery. This can result in slippage of the band which will limit its effectiveness.
Your first band fill will take place 4-6 weeks after surgery. Most often the fills can be done in the office. If the port is hard to locate, you might be asked to have your fill in a radiology suite. The success of the band depends upon good follow-up, especially during the first year. There is an optimal amount of fluid that each band should hold, which varies from patient to patient. If the band is under filled, it will lead to poor weight loss because the outlet will be too big and food will pass too quickly into the main stomach, limiting the feeling of satiety. If the band is too tight, you might develop maladaptive eating behaviors to compensate. You might also turn to high-calorie liquid foods which will be easier to tolerate, but will undermine your weight loss efforts.
Laparoscopic or Minimally Invasive Surgery
For the last decade, laparoscopic procedures have been used in a variety of general surgeries. Many people mistakenly believe that these techniques are still "experimental." In fact, laparoscopy has become the predominant technique in some areas of surgery and has been used for weight loss surgery for the past 6 years at Boston Medical Center.
When a laparoscopic operation is performed, a small video camera is inserted into the abdomen. The surgeon views the procedure on a separate video monitor. Most laparoscopic surgeons believe this gives them better visualization and access to key anatomical structures.
The camera and surgical instruments are inserted through small incisions made in the abdominal wall. This approach is considered less invasive because it replaces the need for one long incision to open the abdomen. A recent study shows that patients having had laparoscopic weight loss surgery experience less pain after surgery resulting in easier breathing and lung function and higher overall oxygen levels. Other realized benefits with laparoscopy have been fewer wound complications such as infection or hernia, and patients returning more quickly to pre-surgical levels of activity.
Laparoscopic procedures for weight loss surgery employ the same principles as their "open" counterparts and produce similar excess weight loss. Not all patients are candidates for this approach, just as all bariatric surgeons are not trained in the advanced techniques required to perform this less invasive method. The American Society for Bariatric Surgery recommends that laparoscopic weight loss surgery should only be performed by surgeons who are experienced in both laparoscopic and open bariatric procedures.
Vertical Sleeve Gastrectomy or Gastric Sleeve
With the sleeve gastrectomy, your stomach will be made smaller by stapling and dividing the majority of your stomach and removing it from your body. The remaining stomach is shaped like a long narrow tube with a small reservoir for food at the end of the tube. This reservoir only holds about 3 ounces of food, meaning you will feel full more quickly and therefore lose weight.
The sleeve gastrectomy retains the normal valve (pylorus) that allows food to exit your stomach. Because of this, the stomach is able to move food into the small intestines at a normal rate, which avoids the dumping syndrome that is common with the gastric bypass procedure. Additionally, the acids and digestive enzymes that help absorb vitamins and minerals are not bypassed during a sleeve gastrectomy, which places you at lower risk for vitamin deficiencies. However, since your stomach is smaller, it will absorb these substances less efficiently, so you will still need to take vitamin replacements.
As you begin to eat and take medications, there will be some swelling of the tube that makes it difficult for any solid food to pass. As a guideline, food should be able to pass through a straw, which is why you are placed on a special liquid diet immediately following surgery. The goal is to let the stomach heal; only liquids and soft solids should be eaten during the first six weeks. Since many pills are quite large and will not fit through the tube, we ask you to crush all medications or take them in liquid or chewable form. You will receive written instructions on the proper diet to follow from your dietitian.