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Metabolic and nutritional derangements Malabsorption of various micronutrients, esp iron, vitamin B12, folate. Hyperoxaluria and nephrolithiasis have been reported following roux-en-Y gastric bypass surgery. Failure to lose weight- Rare Aetiology: maladaptive eating patterns during the early postopera - tive period. Weight regain ( 20 % of patients) Aetiology: Progressive noncompliant eating and other behavioral habits. Development of a functional gastrogastric fistula (between the gastric pouch and the excluded stomach remnant) so food enters the bypasses duodenum Gradual enlargement of the gastric pouch (usually due to excessive food intake) Dilation of the gastrojejunal anastomosis. Complications of mixed restrictive and malabsorptive procedures Ventral incisional hernia is associated with open surgery. Treatment of a ventral incisional hernia involves repair after significant weight loss has occurred (>1 year). Internal hernias which occur with a frequency of 2.5%. Roux-en-Y anatomy assoc with potential internal spaces with small intestine herniation. Treatment of internal hernias involves surgical exploration. Recurrent hyperinsulinemic hypoglycemia is due to beta islet hypertrophy from pancreatic nesidioblastosis). Roux-en-Y gastric bypass Mortality: 0.5% (50% due to leaks/ 30% due to PE’s) Cholelithiasis Frequency: 38 % of patients within six months of surgery. Rapid weight loss contributes to the development of gallstones by increasing the lithogenicity of bile. Obesity itself is also a risk factor. Treatment: Reduce frequency to 2% with 6 month course of UDCA/ prophylactic cholecystectomy at time of main surgery Pulmonary embolus Frequency: 2% despite prophylaxis Risk factors: BMI >60, truncal obesity, and obesity-hypoventilation syndrome. Prevent with stockings and s/c heparin Dumping Dumping occurs early (within one hour after eating) and is not associated with hypoglycemia Aetiology: Contraction of the plasma volume due to fluid shifts into the gastrointestinal tract when high levels of sugar and/or fat are ingested Change in bowel habits Loose stool and diarrhea are more common after BPD and RYGB (46%). Constipation is more likely after gastric banding (40%). Marginal ulcers Frequency: 10% Causes of marginal ulcers include : -Poor tissue perfusion due to tension or ischemia at the anastomosis -Presence of foreign material, such as staples or nonabsorbable suture -Excess acid exposure in the gastric pouch due to gastrogastric fistulas NSAID use Helicobacter pylori infection Smoking Treatment: Usually as per PUD Stomal stenosis Frequency: 10 % Cause: Tissue ischemia or increased tension on the gastrojejunal anastomosis Treatment: Endoscopic balloon dilation is usually successful- may need repeats. Wound infection 10% with open 3% with closed Reduce by closing fascia in running rather than interrupted manner Gastric remnant distension If there is cause for gastric remnant to distend (obstruction/ vagal fibre damage), can perforate Can be prevented by routine gastrostomy if there if concern this might happen (elderly, superobese patients, patients with advanced diabetes, and after revisional surgeries where gastric emptying is delayed) Bleeding Frequency: 2%. Cause: Intraluminal from staple lines. Usually no need for intervention Late bleeding from gastric remnant usually PUD Leaks Average leak rate of 2.5% Treatment: Exploratory surgery- can use stent or glue sometimes MIXED Roux-en-Y gastric bypass-gold standard procedure and the best for long term weight loss Operation: Involves a small (< 30 mL) proximal gastric pouch divided and separated from the stomach remnant with drainage of food to the rest of the gastrointestinal tract via a tight stoma and a Roux-en-Y small bowel arrangement. The small pouch and the tight outlet act to restrict caloric intake, as seen in VBG and LAGB. A much larger gastric remnant becomes disconnected from the food stream while secretion of gastric acid, pepsin, and intrinsic factor continues. The small intestine is then divided at a distance of 30 to 50 cm distal to the Ligament of Treitz. By dividing the bowel, the surgeon creates a proximal biliopancreatic limb that transports the secretions from the gastric remnant, liver, and pancreas. The Roux limb (or alimentary limb) is anastomosed to the new gastric pouch and functions to drain consumed food. The cut ends of the biliopancreatic limb and the Roux limb are then connected 75 to 150 cm distally from the gastrojejunostomy. Major digestion and absorption of nutrients then occurs in the common channel where pancreatic enzymes and bile mix with ingested food. Mixed Procedures
3 potential areas: Mesenteric defect at the jejuno-jejunostomy Between transverse mesocolon and Roux-limb mesentery (Peterson's hernias) (most common) Defect in transverse mesocolon if retrocolic Roux-limb. Gastric bypass-induced weight loss may unmask an underlying beta cell defect or contribute to pathological islet hyperplasia. Treatment: 1.Dietary modification (low carbohydrate diet). 2. If refractory to 1. try alpha-glucosidase inhibitor acarbose. 3.Based on the theory that severe, disabling hypoglycemia after gastric bypass surgery occurs in patients with loss of gastric restriction, with resultant rapid food passage and absorption, restoration of gastric restriction can be therapeutic (ie place a gatsric band). 4.Subtotal pancreatectomy or total pancreatectomy if refractory to above Mixed procedure weight loss causes: Restriction. Dumping syndrome-which acts as a negative conditioning response against consumption of high sugar diet postoperatively. Roux limb length (most surgeons do not make the Roux length longer than 100 cm to achieve the best balance between weight reduction and complications of malabsorption). Gut hormones (ghrelin production- which increases appetite- is produced in the foregut and therefore bypassed. An exaggerated response of peptide YY (PYY) may also contribute to the loss of appetite).
Written by Dr Sebastian Zeki
Outcome: 65 % EWL is reported after the first year. Results are maintained long term, with expected improv - ment in obesity related complaints
