Making Gastric Bypass & Sleeve a Piece of Cake

Although obesity is a chronic problem, most weight-loss programmes based on dietary restriction unfortunately do not lead to long-term weight reduction. The average dieter often finds that over time, they end up heavier than when they began dieting.

On the other hand, bariatric surgery, even in morbidly obese patients, (average BMI 50.2) is quite effective; patients on average lose 60% of their extra weight. It is also safe, as NHS figures show a recorded in-patient mortality of 0.10% while the 30-day mortality was less than 0.17%.

Therefore, should surgery become perhaps a more frequently proposed option for those who suffer from compulsive eating?

In 2012, the classic Roux-en-Y gastric bypass operation made up 80% of all weight-loss surgery in the USA. This operation reduces the volume of the stomach through the creation of a small pouch at the top of the stomach by stapling across the organ. This pouch is then connected to the jejunum down the small intestine, bypassing the rest of the stomach and the duodenum. At the time of eating, the patient quickly feels full and so has no compulsion to overeat. Additionally, the bypass causes malabsorption and metabolic changes which add to the subsequent rapid and sustainable weight loss.

Cutting, stapling and cauterising

Normally performed by laparoscopy, the innovative tools used in the procedure include medical staplers that cut, staple and cauterise the stomach and the intestine; one of the major sources of side effects being leakage from any of these new connections. Covidien manufactures the medical stapler Endo GIA Radial Reload with Tri-Staple Technology. The Tri-Staple technology is special in that it delivers six rows of variable height staples. This allows graduated compression as the staples work in harmony with the natural properties of tissue, generating less tissue stress on clamping, greater perfusion and a lower risk of leakage. Because surgeons face different challenges with different patients, a range of staplers is provided to tackle tissues of different thicknesses, the most robust being the Endo Gia Black designed for extra thick, dense tissues between 2.25 mm and 3.00 mm.

Covidien, now joined with Medtronic, also provides the trocars that enable the surgeon to enter the abdomen. Their range of Versaport Plus Bladeless Trocars allow a controlled, smooth entry with one-step access into the cavity; they have a directional tip to help navigation and a retracting tissue dilation shield that may help limit tissue trauma.

An American company, ValenTx, is currently developing a non-surgical, endoscopically inserted device which they claim will open the gastric bypass procedure up to many more patients. The device mimics the therapeutic mechanisms of a Roux-en-Y gastric bypass but is removable and replaceable, designed to be modifiable in order to change the therapeutic profile, depending on the individual patient’s needs. This device is not yet approved and undergoing clinical tests.

Rise of laparoscopic sleeve gastrectomy

In the meantime, a procedure known as laparoscopic sleeve gastrectomy (LSG) has been rapidly gaining popularity and is now the most frequent definitive bariatric procedure performed in the USA, despite little long-term follow-up data. The central part of the stomach (a sleeve) is removed vertically. The remaining stomach is then sutured/stapled leaving a functional organ about the width of a banana. As with gastric bypass, the patient rapidly feels sated but unlike gastric bypass, the whole length of the stomach is left intact and the whole of the small intestine remains in use. This has the advantage of reducing the malabsorption seen with gastric bypass that can lead to vitamin deficiencies and also allow quasi normal production of gut hormones. As with gastric bypass, results are dramatic with 73% median excess weight loss reported at one year.

Originally performed under open surgery (Magenstrasse and Mill operation), the laparoscopic procedure is now facilitated by inventions like the GastriSail from Medtronic. First of its kind, the GastriSail stops the stomach spiralling during the gastrectomy, a problem when conventional cutting techniques are used. The GastriSail system, approved by the FDA since February, forms a consistent sleeve reducing both operation times and side effects. It should be available in Europe by the end of the year. The removed tissue is evacuated from the body using a specimen retrieval bag, like the one manufactured by Ethicon.

Unknown long-term effects

“To determine which technique is the best for which patient and under what circumstances remains an open question” says Professor Jane Blazeby, from the University of Bristol. “At the moment, health professionals do not know which of these operations is the most effective for long-term weight loss and improvement of health problems and quality of life. Clinical evidence is needed and this is why we have now included the Gastric Sleeve as an arm in our By-Band-Sleeve Study.” The study is scheduled to run until 2020; therefore, until then, surgeons, physicians and patients will have to decide which operation to choose based on the available data.