Vertical Sleeve Gastrectomy
Originally posted January 20, 2012
Updated October 28, 2012
The sleeve gastrectomy is a newer weight reduction procedure that combines mechanical restriction and neurohormonal effects to help patients achieve significant weight loss. The procedure is very straightforward. Eighty-five percent of the stomach is removed leaving a narrow stomach tube or “vertical sleeve” for the passage of food. There is no rearrangement of the intestines. The vagus nerves that innervate the stomach and pyloric valve that regulates outflow of food from the stomach are left intact.
The sleeve gastrectomy procedure evolved from a two part malabsorption procedure called the duodenal switch (DS). In the DS procedure, a fairly wide gastric sleeve was created, and the small intestine was rearranged to cause calorie malabsorption. Some surgeons opted to perform the DS in two stages for safety reasons. The sleeve was constructed first. Then after initial weight loss the intestinal rearrangement was performed. Some of the patients did so well after construction of the sleeve that they did not need to go on to the second part. Thus the concept of the sleeve gastrectomy as a stand alone procedure was born.
The diameter of the sleeve used as part of the sleeve/DS procedure was about 20 mm in diameter. Surgeons subsequently found that their patients could lose more weight if the sleeve diameter was decreased to about 13 mm. There is continuing discussion among surgeons as to the best diameter for the sleeve. The tighter the sleeve, the more restriction and perhaps more weight loss. However a tighter sleeve may lead to more complications. So a balance is needed. A consensus will evolve as more reports are published in surgical journals.
The American Society for Metabolic and Bariatric Surgery (ASMBS) released a white paper on the sleeve in October 2011. The paper can be downloaded here. The ASMBS supports the vertical sleeve gastrectomy as a primary bariatric surgery procedure based on results gathered to date.
As a counterpoint, some authors feel that information gathered so far is insufficient to recommend sleeve gastrectomy as a standalone primary operation. Victorzon writes in a review of current literature: “In conclusion, the quantity, quality, and consistency of evidence concerning LSG for obesity is low. Most of the current evidence comes from poorly designed nonrandomized controlled trials and case series and therefore, there is not yet enough evidence supporting the recommendation of LSG as a definitive, stand-alone procedure for morbid obesity.”
Vertical Sleeve Gastrectomy Procedure
The VSG is performed under a general anesthetic using laparoscopic technique in most cases. The abdomen is inflated with carbon dioxide gas. A laparoscope is introduced into the abdomen, and an examination is made of the abdominal organs. The surgeon measures 3 to 6 cm from the pyloric valve along the outer edge of the stomach and places a marking suture. The blood vessels are disconnected from the stomach along the outer or left side of the stomach. Any adhesions are taken down from the back of the stomach. A surgical stapler is used to divide the stomach. The stapler simultaneously places six parallel rows of staples, and then cuts between them. The cut (transection) is started at the marking stitch and carried upward by a series of firings of the stapler to the top of the stomach near the esophagus until the transection is completed. A sizer, called a bougie, is a flexible tube that is inserted into the stomach as the transection is performed. The bougie helps assure that the sleeve has the desired diameter.
Optimal bougie diameter is under study. The smaller the diameter of the bougie, the tighter the sleeve, and the more the weight loss. However, the tighter the bougie, the higher the chance of leak and of critical narrowing of the sleeve. Aurora found that the leak rate for a bougie diameter of 40 (13 mm) or greater was 0.6%, while for smaller bougie sizes it was 2.8%.
Most surgeons reinforce the staple line in order to decrease chance of leakage from a weak spot in the staple line and to decrease the chance of bleeding from the cut edge of the stomach. The staple line can be reinforced by either oversewing it or by using a buttressing material applied to the stapler. The advantages of reinforcement are investigated in a meta-analysis by Choi.
Once the transection is completed, the portion of the stomach that has been excised is removed from the abdomen. The surgeon then checks the staple lines to make sure that there isn’t any bleeding. The gas is removed from the abdomen, and the small skin incisions are closed with stitches under the skin. The skin edges are then glued together.
Since the sleeve gastrectomy is a new procedure, experts are still working out the details of the "optimal" procedure. Rosenthal reports on progress to this end.
Most patients stay in the hospital for two to three nights after surgery. The length of stay depends on the general health of the patient, recovery from anesthetic drugs, evidence of that there is no bleeding, ability to take liquids, general sense of well being, and the patient’s home situation and support.
Recovery depends to a large part on the patient’s general medical condition before surgery. Although this varies widely, most patients can return to work two to four weeks after surgery. Patients who do heavy lifting at work may want to recover for an additional week or two. It is always better to overestimate time off work than to try to get back to work too soon.
Weight Loss Results
Vertical Sleeve Gastrectomy Results
Author.....Number of patients....Follow-up....Weight Loss
Johnston........16.............................5 years......61% EWL*
Weiner.............8.............................5 years......- 17 BMI
Himpens.........41............................6 years.......53% EWL
Bohdjalian......26............................5 years.......55% EWL
D’Hondt..........23............................6 years.......56% EWL
* EWL: Excess Weight Loss
(table extracted from ASMBS white paper on Sleeve Gastrectomy, see above)
These weight loss results are encouraging. However the number of patients who have been followed for 5 or more years is still small, so one should be cautious when interpreting the results.
There are three recent randomized prospective trials that compare sleeve gastrectomy with gastric bypass. Click on the authors' name to view an abstract (summary) of each article. The first, by Kehagias compares 30 patients with sleeve gastrectomy to 30 patients with gastric bypass followed for 3 years. The authors could find no statistically significant difference in weight loss or overall complication rates between the two procedures. There were only 5 diabetics in each group. So no conclusions could be made regarding the relative effectiveness of the two procedures for diabetes, or for recover from any other comorbidity for that matter.
The second randomized trial reported by Lee from Taiwan compares the effect of gastric bypass to sleeve gastrectomy on relief from diabetes in low BMI patients. The study was designed to look at the results and mechanism of action of the two surgeries specifically on diabetics. There were a total of 60 patients in the trial, evenly divided between the two procedures. After two years the gastric bypass group achieved significantly better results.
The third randomized trial reported by Woelnerhanssen compared the effects of gastric bypass to sleeve gastrectomy on metabolic measurements made during the first year after surgery. There were 12 and 11 patients in each group respectively and they were all non-diabetic. Both groups saw significant weight loss, decrease in serum leptin levels, increase in adiponectin levels, and improved insulin sensitivity. There were no statistically significant differences in these results between the bypass and sleeve groups.
These results are important, but the reader should be cautioned to take them at face value and not draw overreaching conclusions. The numbers of patients in each group is small and the follow up period is short. Whether these differences will hold up over the long run and whether the differences will be apparent in higher BMI patients remains to be seen.
Relief from Comorbid Medical Conditions Results
Type II Diabetes Mellitus
In a landmark randomized prospective trial from the Cleveland Clinic Schauer reported that at one year sleeve gastrectomy and gastric bypass were significantly more effective than optimized medical therapy for the treatment of moderate to severe diabetes. Similar results have been found in several less scientifically rigorous studies: Nocca, Abbatini, Leonetti, and Hady.
Vertical Sleeve Gastrectomy Risks and Complications
Vertical sleeve gastrectomy is major surgery that is performed on patients who are often in poor medical condition. While many complications can be prevented by thorough preparation of the patient before surgery, skillful anesthesia, and careful surgery, some complications will occur anyway.
Major early complications include bleeding from the staple line requiring transfusion or possible reoperation (1%), staple line leaks (2.4%), and blood clot to the lungs (0.3%). In rare instances the sleeve can be too tight because of a partial twist or because of scarring. Other very uncommon post op problems include injury to the spleen, pancreatitis, and portal vein thrombosis (0.7%).
The mortality rate after vertical sleeve gastrectomy has been reported in the range of 2/1000. Causes of death include pulmonary embolism (blood clot to the lungs), infection following leaks, pneumonia, cardiac irregularities or heart attack, stroke, and other rare events.
Long term problems can include development esophageal reflux, sleeve dilation with resultant decrease of restriction, and rarely bowel obstruction due to adhesions (scars inside of the abdomen). Vitamin deficiency can occur if patients do not eat a healthy diet and do not take certain vitamin supplements. These supplements include multivitamins, B12, and in some cases iron. Other vitamins may be necessary. Vitamin levels can be checked with blood tests, so long term deficiencies can be prevented.
One of the problems that some patients face after sleeve gastrectomy is the development of esophageal reflux. Reflux causes heartburn and esophagitis. It may occur soon after sleeve gastrectomy or may appear after several years. There are probably several causes for reflux, and the problem has not been extensively researched. The sleeve itself can be obstructive. It is a long narrow tube. If it is too tight, it may not function well. Second, the upper part of the sleeve may dilate slowly creating a small pouch. The pouch narrows into the sleeve. Food can accumulate in the pouch and reflux. Third, a patient may develop problems with motility of the esophagus or with the sphincter muscle between the esophagus and stomach. And fourth, some patients may develop a hiatus hernia over time. A hiatus hernia is a widening of the diaphragm at the point where the esophagus passes from the chest into the abdomen. When a hiatus hernia develops, the stomach slips into the chest and the sphincter muscle at the end of the esophagus becomes less effective. Reflux occurs when the sphincter is weak.
The first line of treatment for reflux is use of acid blockers and avoidance of acid stimulating foods. A hiatus hernia can be repaired. If antacids don’t work, the sleeve gastrectomy can be converted to a gastric bypass, usually by a laparoscopic approach.
Staple line leak
Staple line leaks occur infrequently in all abdominal surgeries where staples are used to divide and/or connect bowel. Leaks have been reported to occur in 0 – 4% (2.4% average) of sleeve gastrectomy cases. The cause of staple line leaks is usually an area of tissue weakness somewhere along the staple line. When the weakened tissue breaks down, fluid from within the stomach leaks out into the peritoneal cavity causing an infection. Treatment of leaks has traditionally involved surgical or x-ray guided drainage of the leak, antibiotics, and intravenous or enteral (intestinal) nutrition. Various techniques are often used to reinforce the staple line, but none is completely effective.
After the infection associated with a leak is controlled, the next goal is to get the leak to heal. 90% of sleeve leaks occur at the top of the staple line. This location is vulnerable because the narrowness of the sleeve causes a high pressure zone at the upper end of the sleeve. Because of the high pressure, it is often time consuming and difficult to get the leak to heal. A new technique has been introduced to hasten recovery from sleeve gastrectomy staple line leaks. A self expanding tube called a stent can be introduced into the sleeve using an endoscope. The stent expands to close the leak. The stent is hollow allowing passage of food into the stomach during the healing process. Here is a report of three patients treated successfully with stents: Nguyen.
The incidence of staple line bleeding requiring a transfusion is about 1% following vertical sleeve gastrectomy. Bleeding most often occurs from the staple line. It can also occur from vessels in the abdominal wall that may be punctured by the laparoscopic instruments, from the spleen, or from the blood vessels of the omentum where it is divided from the stomach. many surgeons will either oversew the staple line or use reinforcement materials on the staple line. Most surgeons find that use of these techniques reduces bleeding. For more information see this abstract by Dapri.
Almost all patients who undergo obesity surgery are placed on low doses of blood thinners before surgery to prevent blood clots that can go to the lungs. A side effect of the blood thinners is a bleeding tendency. Fortunately bleeding is uncommon and the blood thinners are quite effective at reducing risk of blood clots. It would be extremely unlikely for a patient to die from staple line bleeding with the availability of modern blood banking. If a patient will not accept a blood transfusion because or religious reasons, the surgeon might recommend early return to the operating room to stop the bleeding surgically rather than run the risk of a fatality due to blood loss.
Vitamin and mineral deficiencies have been documented after all bariatric surgical procedures. 40-60% of patients have deficiencies before surgery due to inadequate diet and lack of sun exposure (vitamin D). After bariatric surgery, the chance of deficiencies increases unless the diet is carefully chosen and unless patients take appropriate vitamin and mineral supplementation.
Studies are just beginning to be published on the effects of sleeve gastrectomy on vitamin and mineral levels. Removal of much of the stomach eliminates the churning, mixing, and breakdown effect on food. Enzymes and acids secreted by the stomach decrease. A chemical called Intrinsic Factor, necessary for the absorption of B12, is produced by the stomach and is therefore decreased after sleeve gastrectomy.
Danns-Machado reports, “LSG had a modest effect on micronutrient status by further reducing iron, vitamin B12, vitamin B6, and folate within the first year after intervention.” He goes on to state, “Our data suggest that especially obese patients with preoperative deficits require control and supplementation of micronutrients and protein in the postoperative period.”
Vitamin B1 deficiency is uncommon but can cause serious and permanent neurological injury. Three recent reports and one older report of B1 deficiency have been published: Scarano, Moize, Jeong, and Makarewicz. It thus seems imperative that a patient discuss B1 supplementation and measurement of whole blood B1 levels with their surgeon.
Vitamin D levels and other micronutrient levels were followed for up to 5 years by Saif. This study found that “The vitamin D level was less than normal in 42% of the patients at year 5. After normalization from baseline, by year 5, parathyroid hormone had increased in 58.3% of patients. At year 5, vitamin B(1) was less than normal in 30.8% of patients, and hemoglobin and hematocrit were less than normal in for 28.6% and 25% of patients, respectively.” What they also found was that many patients failed to take vitamin and mineral supplements: “28.9% of patients reported taking supplements in year 1, 42.9% in year 3, and 63.3% in year 5.” Once again this study shows that vitamin and mineral deficiencies are common, and it is imperative for patients to take vitamin and mineral supplementation recommendations to heart.
Patients may develop "dumping syndrome" as a reaction to sweet foods after a wide range of stomach surgeries. When a person with normal anatomy consumes sweet food or drink (think cheesecake or fruit smoothies), the food is gradually released from the stomach into the small intestine. Following a stomach surgery, the food is released more quickly, and the sugars or fats can overwhelm the ability of the small bowel to handle it. The result is a syndrome that often includes a hot flash, nausea, weakness, sometimes diarrhea, sometimes hypoglycemia, and other symptoms. For a full discussion of dumping syndrome download the article attached at the bottom.
Dumping syndrome occurs when the stomach empties its contents more rapidly than usual. Rapid emptying is thought to occur after sleeve gastrectomy as cited by Melissas.
The first study to systematically test sleeve patients for dumping was published in October 2012 by Papamargaritis. He found that dumping occurred in 40% of sleeve patients at 6 months after surgery and 33% at 12 months.
Mild dumping syndrome can act as a deterrent to help patients avoid very sugary foods. Moderate or severe dumping can be very problematic. Dumping syndrome can be minimized by keeping the sugar and concentrated fat content of meals low, by keeping meals small, by not drinking liquids with meals, and by waiting to drink liquids for 30 minutes after a meal.
Vertical sleeve gastrectomy is a new weight loss surgery that has become popular in the last few years. Early reports suggest that weight loss results will probably fall between those of the adjustable gastric band and gastric bypass. The sleeve gastrectomy is appealing because of its apparent simplicity. There are several problems that can follow gastric bypass that are not seen with the sleeve. These include anastomotic ulcers and bowel obstructions. However, it appears that vitamin deficiencies and dumping syndrome are common after both procedures. Since there is so little long term data for the sleeve, we do not yet know the results at 5 or 10 years for reduction of diabetes, obstructive sleep apnea, or hypertension compared with gastric bypass. Finally, we do not know how big an issue late development of esophageal reflux will become. We look forward to the medical reports that will be forthcoming in the next few years.