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(Amended 2002)
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CHAPTER-4
The Mason era |
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GASTRIC BYPASS: The complications of gastric bypass are much less severe than those of Intestinal Bypass, and most large series report complications in two phases, those which occur shortly after surgery, and those which take a longer time to develop. The most serious acute complications include leaks at the junction of stomach and small intestine. This dangerous complication usually requires that the patient be Complications which occur later on after the incision is all healed, include narrowing of the stoma (the Another late problem which is fairly common, especially in menstruating women, after gastric bypass is anemia. Since the stomach is involved in iron and Vitamin B12 absorption, these may not be absorbed adequately following bypass. As a result anemia may develop. The patient feels tired and listless, and blood tests show low levels of hematocrit, hemoglobin, iron, Vitamin B12. The condition can be prevented and treated, if necessary, by taking extra iron and B12. Since the food stream bypasses the duodenum, the primary site of calcium absorption, the possibility of calcium deficiency exists, and all patients should take supplemental calcium to forestall this. Dumping is often mentioned as a complication of gastric bypass, but it really is a side effect of the Early:
Late:
Silastic Ring Gastric Bypass: Vertical banded gastric bypass (Fobi) The use of rings to control the stoma size, proven with Vertical Banded Gastroplasty, has led to their adoption by some surgeons as an addition to gastric bypass procedures, again to control the stoma size and prevent late stretching of the opening and, hopefully, improve the long term weight maintenance results. Both silastic rings and Marlex bands have been used. Usually the recommendation is for the ring circumference to be considerably larger than that used in primary obesity procedures, so that the limiting effect only comes into play after some degree of stretching of the pouch has occurred. The early use of such stapling devices in obesity surgery involved removal of three staples from the row and firing the stapler across the top part of the stomach. This staples the two stomach walls together, except at the point where the three staples were removed, where a small gap remains. The idea being that food which the patient takes in is held up in the segment of stomach above the staple line causing the sensation of fullness. The food then empties slowly through the gap (stoma) into the stomach below the staple line where digestion takes place normally. Unfortunately, the muscular stomach wall has a tendency to stretch and the stoma enlarges. It soon became apparent that while patients lost weight for the first few months while the stoma was small, they soon stopped losing, and, indeed, frequently regained all they had lost. Of course, surgeons tried to counter this by reinforcing the opening between the two compartments (Gomez 1981),
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Gastric Bypass (RGB) was developed by Dr Edward E. Mason, of the University of Iowa, based on the observation that females who had undergone partial gastrectomy for peptic ulcer disease, tended to remain underweight following the surgery, and that it was very difficult to achieve weight gain in this patient group. He therefore applied the principles of partial gastrectomy to obese females, finding that they did indeed lose weight. (Mason and Ito 1967) With the availability of surgical staples, he was able to create a partition across the upper stomach using staples, and did not require removal of any of the stomach. Subsequent modifications of the technique include a pouch of 50 ml or less, a gastro-enterostomy stoma of 0.9 mm, use of the Roux-en-Y technique to avoid loop gastroenterostomy and the bile reflux which may ensue. Lengthening of the Roux limb to 100-150 cms to include a greater element of malabsorption and improve weight loss and the use of the retrocolic and retrogastric routing of the gastrojejunostomy to ease the technical difficulties of the procedure and improve long term weight loss
results. Staple line failures have been found to occur many years after the procedure, in consequence surgeons have responded by use of techniques designed to prevent this. These include transection of the stomach, in which the staple line is divided and the cut ends oversewn. An alternative technique using superimposed staple rows is claimed to exert its effect by crushing the stomach tissue causing firm scarring along the staple line. Additionally, there have been attempts to stabilize the gastroenterostomy by the use of a prosthetic band, fashioned into a ring positioned just above the junction of gastric pouch and small intestine. Gastric Bypass has also stood the test of time, with one series of greater than 500 cases, followed for 14 years, maintaining 50% excess weight loss.
returned to surgery on an urgent basis, as does the rare acute gastric dilatation, which may arise spontaneously or secondary to a blockage occurring at the Y-shaped anastomosis (jejunojejunostomy). Then there are the complications to which any obese patient having surgery is prone, these including degrees of lung collapse (atelectasis) which occur because it is hard for the patient to breathe deeply when in pain. In consequence a great deal of attention is paid in the postoperative period to encouraging deep breathing and patient activity to try to minimize the problem. Blood clots affecting the legs are more common in overweight patients and carry the risk of breaking off and being carried to the lungs as a pulmonary embolus. This is the reason obese patients are usually anticoagulated before surgery with a low dose of Heparin or other anticoagulant. Wound infections and fluid collections are quite common in morbidly obese patients, hardly surprising when you realize there may be five or six inches of fatty tissue outside the muscle layers of the abdomen.
junction between stomach pouch and intestine), which results from scar tissue development. Recall that this opening is made about 10 mm in diameter, not much wider than dime. With an opening this small, a very little scarring will squeeze the opening down to a degree that affects the patients eating. Vomiting which comes on between the 4th and 12th week may well be due to this cause. The problem can be very simply dealt with by stretching the opening to the correct size, by "endoscopic balloon dilatation", which usually involves a single procedure on a day stay basis to correct the problem. Wound hernias occur in 5-10% and intestinal obstruction in 2% of patients an incidence similar to that following any general surgical abdominal procedure.
procedure caused by the way the intestine is hooked up. Dumping occurs when the patient eats refined sugar following gastric bypass, this causes symptoms of rapid heart beat, nausea, tremor and faint feeling, sometimes followed by diarrhea. Of course no one likes these feelings, especially patients who love sweets! The upshot is, of course, that sweet lovers avoid sweets after gastric bypass and this is a real help to them in their efforts to lose weight.
These are capable of laying down as many as four parallel rows of staples, to create a partition, or the instrument comes with a knife blade which will cut between the newly placed staple rows, dividing and sealing the stapled tissues simultaneously. Other instruments place circular rows of staples which will join two tubes end to end, very useful in connecting intestine together.
techniques which were only partially successful. The search for a better gastroplasty was pursued by Dr. Edward E. Mason, Professor of Surgery at the University of Iowa. (Mason 1982) He realized that the lesser curvature part of the stomach had the thickest wall and was therefore least likely to stretch, so he used a vertical segment of stomach along the lesser curvature for the pouch. Additionally, he was very meticulous in defining the size of the pouch, measuring it at surgery under a standard hydrostatic pressure, and has shown that best results follow the use of a very small pouch, holding only 14 ccs saline at the time of surgery. The third modification which he made was to place a polypropylene band (Marlex Mesh) around the lower end of the vertical pouch, which acts as the stoma, to fix the size of the outlet of the pouch, preventing it from stretching. This is done by use of the circular stapling instrument to staple the front and back walls of the stomach together, cutting out a circular window to allow the polypropylene band to be placed around the lower end of the pouch. His extensive studies showed that the correct circumference of the band is 5.0 cms. The whole operation is called Vertical Banded Gastroplasty (VBG). Correctly performed this operation produces good weight loss results. It has the advantages of being a pure restrictive procedure with no malabsorption component and no dumping. Of course sweet eaters will have to avoid
sweets on their own if they have this procedure. Similarly there are few complications associated with Vertical Banded Gastroplasty, because all food taken in is digested normally, and anemia is rare and Vitamin B12 deficiency is almost unknown. The patient does have to be very careful to chew food completely to avoid vomiting, and to avoid high calorie liquids such as regular sodas and ice cream which go down pretty well! A surgical variant of the VBG is the Silastic Ring Vertical Gastroplasty (SRVG) which is functionally identical to VBG but uses a silastic ring to control the stoma size. It should be noted that a few surgeons, expert in minimal access surgery are performing gastroplasty using laparoscopic techniques.
