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Adjustable Gastric Banding (AGB) procedures have been presented and promoted as innocuous and low risk in nature. AGB still carries significant risks although its perioperative complication rate appears to be less compared to other weight loss surgical procedures. Such risks include permanent and potentially life-threatening damages or other complications if proper treatment isn’t sought in an urgent manner.

Often times a patient’s complaints are minimized and blamed on behavior or their presumed non-compliance. Quite frequently they are only referred to a surgeon after exhaustive workup has been completed and mostly reported back as normal. These workups include upper GI series and endoscopic studies. Nevertheless, the complication(s) with which a patient may have been presented with still continue.

I would like to discuss two such examples in which patient care may have been delayed.

The first patient was a 45-year-old male who had the AGB procedure completed approximately two years prior to her first visit to our office. He presented complaints of abdominal pain and worsening reflux. He had had multiple adjustments at his primary surgeon’s office and was told to be in the optimal “green zone” for the band. He had lost approximately 45% of his excess weight, but continued to have significant debilitating reflux.

An upper endoscopy was reported to be normal and consistent with a properly placed band. An upper GI performed months later identified a dilated esophagus, requiring the band to be removed. In hindsight, the band should have been completely emptied upon the patient’s first complaints of abdominal pain and reflux.

The next patient visited a local emergency room with acute onset of nausea and vomiting. She was sent home with a diagnosis of gastroenteritis and instructed to follow up with her primary care physician. She returned back to the emergency room within 36 hours with a progressively worsening nausea and vomiting. She was admitted and underwent an upper endoscopy after which a surgical consultation was obtained. The patient was taken to the operating room with a diagnosis of “slipped band”, and had to have the band removed emergently. Looking back at this case, the abdominal x-ray was suspicious for a slipped band. She should have been referred for surgical care at the time of her first emergency room visit.

Ultimately, the burden of proof is on the medical provider treating the patient with an AGB to ensure that there is no slippage when the patient presents with acute changes in his or her condition. The AGB may still “appear” to be in the proper place and adjusted with the patient still having symptoms of reflux, inadequate weight loss, and abdominal pain. These patients would require surgical intervention and probably removal of the band.

As indicated earlier, the patients’ complaints should not be discounted as being a compliance issue and instead should be referred for surgical evaluation.

The Duodenal Switch procedure is a restrictive and malabsorptive weight loss surgery. Also, referred to as Gastric Reduction Duodenal Switch (GRDS).

Duodenal Switch Anatomy

1 – Restrictive Component

Approximately 70% of the stomach is removed along the greater curvature. This is also called a Vertical Sleeve Gastrectomy (VSG). The remaining stomach is fully functioning, banana shaped and about 3 – 5 oz. in size; which restricts the amount you can consume. The pylorus, part of stomach, continues to control the stomach emptying into the small intestine; as a result patients do not experience “dumping”. The upper portion of the duodenum remains in use; food digests to an absorbable consistency in the stomach before moving into the small intestine. Compared to gastric bypass procedures, this allows for better absorption of nutrients like vitamin B12, calcium, iron and protein. A benefit of removing a portion of the stomach is it greatly reduces the amount of ghrelin producing tissue and amount of acid in the stomach. Ghrelin is the “hunger hormone” and by reducing the amount the hormone produces, the appetite is suppressed. The stomach will stretch over time; 9-12 months post-op, it will eventually double in size and patients will be able to consume approximately 50% of what they did before surgery. The restrictive component of the Duodenal Switch procedure is not reversible.

2 – Malabsorptive Component

The intestines are re-routed so that food from the stomach, alimentary limb, and the digestive juices, biliopancreatic limb, that are needed for the absorption of fat and proteins can travel separate paths; this is so they don’t mix until they meet up towards the end of the small intestine.

The common channel, also known as the common tract or common limb, is the point from where the alimentary and biliopancreatic limbs meet in the small intestine to move into the large intestine. The common channel is where a DS patient’s food, bile and digestive juices mix; the majority of the fat, protein and the associated nutrients are absorbed. Since the common channel makes up such a small portion of the small intestine the dietary starches, fats and complex carbohydrates may not fully absorbed.

The most commonly quoted absorption percentages following DS are approximately 20% of fats, 60% of protein, 60% of complex carbohydrates, but 100% of simple carbohydrates. The 2005 study by Gagner et al. [68] demonstrated that DS surgery decreased fat absorption by 81%. The Bariatric Nutrition: Suggestions for the Surgical Weight Loss Patient review reports information from a study by Slater et al. stating that “After BPD/DS procedures, the amount of protein should be increased by ~ 30% to accommodate for malabsorption, making the average protein requirement for these patients approximately 90 g/d.” [65]

The malabsorption of fats interferes with absorption of the fat-soluble vitamins A, D, E & K. As a result all Duodenal Switch patients are required to take vitamin and mineral supplements for life. Patients must be diligent with the required supplements and have blood work monitored regularly. Also, they must adjust their supplements as needed to maintain normal levels of these vitamins and minerals.

The intestinal switch portion of the Duodenal Switch procedure is fully reversible.

Metabolic Effect

There is no dispute that Duodenal Switch produces the best-sustained weight loss, and has the best resolution rate for most comorbidities of all weight loss surgical procedures. These results cannot be simply explained by the restrictive and the malabsorptive component of DS. The general consensus is: that there are a number of hormonal regulatory changes involving Ghrelin, GLP-1, Enteroglucagon, Insulin, and others hormones (enzymes) that regulate the complex endocrine pathways.

Hess Method

Many often hear Duodenal Switch procedure patients using the term “Hess Method” [1] when discussing common channel length. Dr. Hess in Dublin Business News Monthly calculated the length of the alimentary limb by multiplying the total small bowel length by 40%. The remaining 60% of intestine carries the digestive juices through the biliopancreatic limb. The length of the common channel is approximately 10% of the total length of the small bowel. “Hess Method” refers to following Dr. Hess’s calculation for determining the limb lengths and common channel length, but other factors are taken into consideration; like the patient’s age, weight, BMI and goals. Each patient has a different length of common channel and alimentary loop designed to achieve the best results. “Length Measurement in Duodenal Switch” is discussed and explained in detail at https://www.dssurgery.com/procedures/streaming-media.php

Not all surgeons use the “Hess Method”, but some surgeon’s use a standard measure for the common channel of 100 cm and 150 cm, which is often used.

Ask a surgeon how he/she determines common channel length.

Appendix and Gallbladder

Some surgeons will remove the appendix because there is almost no extra effort that is placed in removal of the appendix, since the small bowel is measured from the junction of the colon and the appendix.

Few surgeons routinely remove the gallbladder because there is a 30-50% chance of gallstones forming after rapid weight loss. [56-57] For patients whose gallbladder is not removed often, medication is prescribed to help reduce the instance of gallstones from 30% to 2%. [57] One other compelling reason why the gallbladder should be removed is because of the inaccessibility of the biliary tree by a specialized endoscopic technique ERCP. The medication that is also prescribed has frequent side effects that limit their use and compliance with patients.

Staged Duodenal Switch

Duodenal Switch is sometimes performed in two stages when the surgeon determines it is too risky for the patient to undergo the whole procedure at once. This is usually a result of a patient’s age, BMI, comorbidities or for a more difficult revision surgery. The surgeon will perform stage one, restrictive component, then when the patient has lost some weight and the other health issues clear up then stage two, intestine switch, is performed.

For more information on the Duodenal Switch procedure:

Central Valley Bariatrics Graphical Comparison of Weight Loss Surgery Procedures 

Central Valley Bariatrics Outcomes Comparison Chart 

Central Valley Bariatrics Videos