This blog provides free general information for anyone who is seeking to understand more about the complications of laparoscopic sleeve gastrectomy, not intended as a medical consult. Please seek proper medical advice for individual assessment and management.
The crucial learning points are:
- The benefits of laparoscopic sleeve gastrectomy
- Immediate post op and short/medium term complications
- Long term nutritional and weight regain issues
The advantages of a laparoscopic sleeve gastrectomy
This operation is not new because variations of the sleeve gastrectomy have been performed in the past. However not until recently, it has been done as a stand alone bariatric surgical procedure with proven good weight loss result and resolution of medical co-morbidities in the medium term.
Hence this procedure has rapidly increased in popularity around the world. The listed advantages include:
- The surgery is technically more simple compared to the gastric bypass and it has a lower risk profile.
- The sleeve gastrectomy offers a restrictive effect (to prevent over eating) and produces beneficial hind gut hormone changes as well (for post prandial satiety and incretin effect).
- Sleeve gastrectomy has promising short and medium term weight loss results with resolution of obesity related medical co-morbidities, the result is comparable with gastric bypass.
- Sleeve gastrectomy has sustainable beneficial effect on glycemic control (may delay or prevent microvascular end organ complications from Type 2 diabetes mellitus), control for cardiovascular risk factors and is effective in reducing morbidity and premature mortality.
- The surgery is low maintenance (compared to the gastric band) and lacks the undesirable malabsorption side effects of a long limb gastric bypass or BPD-DS procedure.
The history of sleeve gastrectomy
Intially sleeve gastrectomy was performed as an open procedure in 1988, known as the Hess and Marceau operation, which is actually the first stage of the bilio-pancreatic diversion-duodenal switch (BPD-DS).
In 1993 it was proposed as a single weight loss procedure described by Johnston, which later became known as the Magenstrasse and Mill operation.
In 1999 Gagner was the first to describe the laparoscopic sleeve gastrectomy technique.
Since 2003 it has gained popularity as a one stage (stand alone) definitive surgical treatment for morbid obesity and related co-morbidities, with reported up to 60% excess weight loss result (after 5 years follow up results) and good resolution of Type 2 diabetes mellitus, comparable to Roux Y gastric bypass.
Patients may take comfort in knowing that the sleeve gastrectomy has been performed for several decades but like any operation, there are post operative complications (both general and specific to the sleeve) that need to be discussed.
Post operative nausea and vomiting
After general anaesthetic and gastric volume reduction surgery, post op nausea and vomiting may occur in the first 24-48 hours.
The diameter of the remnant sleeved stomach definitely plays a role in the patient’s tolerance of post op oral fluid intake.
Most patients can only sip small quantities of water or fluids in the first 2 weeks (eg. 30-60mls/hour to start with in the first 2 days).
- The thinner the sleeve, the smaller the intrinsic stomach volume, the greater the weight loss (in the long term) but also the greater the risk for staple line leak and post op nausea/vomiting (in the short term).
Some researchers divide the sleeved patients into 2 groups:
- Type 1 (faster gastric transit <30minutes) (lax sleeve) are those who are more likely to tolerate oral fluids or food better immediately post op, achieve weight stabilization in 6 months but also has more propensity for the stomach remnant to stretch with poorer weight loss results in the longer term.
- Type 2 (slower gastric transit >30 minutes) (tighter sleeve) are those who are more likely to experience more nausea side effects early on after surgery but have better weight loss results in the longer term (patients are more likely to continue to lose weight after 6 months and maintain the weight loss beyond 3 years).
Large volume eaters and patients with binge eating are more likely to benefit from a tighter sleeve than a lax sleeve.
Venous thrombo-embolism (VTE)
Deep venous thrombosis (DVT) is blood clot in the legs and pulmonary embolus (PE) is blood clots in the lungs. These two complications are a major cause of morbidity and mortality after any general or bariatric surgery.
In the absence of thrombo-prophylaxis, DVT is estimated to occur in more than 20% of patients undergoing bariatric surgery and post op PE can occur in 25% of patients.
The risk for DVT and PE continues for up to 3 months but most tend to occur within the first 30 days after bariatric surgery.
With an active thrombo-prophylactic plan the risk of venous thrombo-embolism is estimated to be less than 1%.
The prevention of blood clots includes:
- Low molecular weight heparin (LMWH) subcutaneous injection which is first given on the day of surgery and continue for the duration of the hospital stay.
- Graduated compression stockings (TED) are worn by patients when they are admitted to hospital and may be worn for 2 weeks (or more) after discharge.
- Intermittent sequential pneumatic calf compression device (SCD) are utilized in theatre when the surgery begins and may be continue in the wards for 1-2 days.
- Early mobilization and return to pre op baseline activity level immediately after surgery is encouraged.
- Prevention of dehydration also helps reduce blood clots.
LMWH that is given is usually enoxaparin (Clexane or Lovenox) as subcutaneous injection once a day. The medication doses for bariatric surgery patients are often higher than normal weight patients.
- Enoxaparin 40mg (for BMI<60), 50mg (for BMI 60-70) or 60mg (for BMI>70).
- Enoxaparin 20mg (is the dose required for those with kidney disorder, eGFR<30ml/min regardless of body weight).
Very high risk patient may require LMWH injection continued for 2 weeks post op.
*Note: in contrast The Australian and New Zealand Working Party on Management and Prevention of VTE (4th Edition) only recommends only 20mg enoxaparin for major non cancer surgeries for those over 40 years of age.
Staple line problems
Bleeding may occur anywhere along the staple line, usually in the first few days whilst the patients are still in hospital and often managed conservatively.
Rarely blood transfusions are given if the blood loss is significant.
In the surgical literature the risk of staple line leak has been reported to be from 0-10%.
Leakage is the most commonly discussed post op complication during the consultation, to raise awareness of the seriousness of the consequence of a leak.
- The highest risk group are amongst male, age over 55 years, BMI>50 and for revisional bariatric surgeries.
- Leakage may occur in the acute post op period (within 2 weeks), early (in the first 2-3 months) or late (after 12 weeks) phase.
- Leakage may be a result of staple malfunction, technical errors, thermal injury, gastric ischemia or from distal obstruction (narrowing or kink around the incisura).
Management of staple line leak may be difficult, may involved multiple return to theatres and prolonged stay in hospital.
Late stricture rate has been reported to occur around 0.5%.
Heartburn symptoms are common in obese patients, which may be a pre-existing problem attributed to a raised intra abdominal pressure and the concurrent presence of a hiatus hernia.
- Hence most experts recommend repair of a hiatus hernia at the same time as the sleeve gastrectomy, if this is seen at the time of surgery.
Early post op heartburn symptoms for most sleeved patients are transient and can be managed with oral medications (eg. Nexium).
Heartburn is probably the most common complaint after LSG in the long term.
Careful re-assessment of the patient is needed to exclude a hiatus hernia or gastric stricture (distal staple line stenosis), where further surgery may be needed.
Dumping syndromes are more common with gastric bypass than sleeve gastrectomy.
Initially it may have the desirable effects on “sweet” food avoidance but in the longer term reactive hypoglycaemia may worsen maladaptive eating behaviour (grazing behaviour and increase total calorie intake).
Weight regain have been attributed to dumping syndrome, rapid intestinal transit and over stimulation caused by increased release of distal gut hormones.
Nutritional deficiencies are common after malabsorptive operation (such as the gastric bypass, bilio-pancreatic diversions or duodenal switch) and typically refer to iron, folate, calcium, vitamin D and vitamin B deficiencies.
The average adult body contains 3-4g of iron (adult man have 1g iron in stores and women 300mg) and measured serum ferritin levels (in non inflamed states) correlate with body iron stores.
Iron is mainly absorbed in the duodenum and transported to the bone marrow for red cell production or being stored.
- Most of the body’s iron is for red blood cell production, the rest for the reticulo-endothelial system and liver parenchymal cells.
- Iron is normally lost with shedding of epithelial cells or menstrual blood loss (average 1-2mg/day) and needs to be replaced by dietary iron (with smaller replacement or contribution from body iron stores).
If large portion of iron is needed for red blood cell production then reduced a dietary iron or absorption will inevitably lead to iron deficiency anaemia.
- Thus iron deficiency anaemia is more common in younger females of reproductive age (especially with heavy menstrual periods).
Iron deficiency may increase over time as body stores of iron are diminished.
After surgery iron deficiencies may occur in 20-50% of patients and mainly due to:
- Reduced dietary sources rich in iron (ie. inadequate red meat in the diet).
- Reduced gastric acid secretion (that is necessary for reduction of ferric iron to ferrous iron which is then absorbed).
- In gastric bypass the proximal intestinal absorption (from the excluded duodenum and proximal jejunum) is lost.
Normally after gastric bypass patients are prescribed ferrous sulphate tablets, current recommendation is 40-65mg/day (2-5 times the amount of elemental iron found in a common multivitamin tablet).
- Some patients take ferrous sulphate (325mg) 3 times a day but nausea and constipation side effects are common.
- In rare circumstance intravenous iron dextran infusion may be required and needs to be given in hospital (ie. to replenish the depleted body iron stores).
Vitamin B12 and folate deficiency
B12 absorption requires hydrochloric acid and intrinsic factor (from gastric mucosa) for absorption in the terminal ileum.
After surgery patients are recommended to increase red meat intake (a good source of folic acid and vitamin B12).
Folate absorption occurs through out the small bowel but mostly in the jejunum
Deficiency usually result from reduced oral intake.
Calcium and vitamin D deficiency
Weight loss is often associated with reduced intake or absorption of calcium and vitamin D.
Caloric restriction, reduced oral intake of dairy foods and vitamin D combined with lack of routine exercise may result in raised parathyroid hormone (secondary hyperparathyrodism), increased bone resorption and eventually osteoporosis.
Deficiency may result in skeletal muscle myopathy, cardiomyopathy, muscle wasting, arrhythmia, reduced immunity and reduced thyroid function.
Other possibilities include loss of skin and hair pigment, white nail beds and progressive encephalopathy.
Absorption of selenium may be enhanced by anti-oxidants like vitamin C and E.
Increased oxalate absorption
Dietary oxalate are commonly found in chocolate, tea and vegetables.
This is usually precipitated as calcium oxalate in the intestine and eliminated in the stools without being absorbed.
In bile salt malabsorption or short gut syndrome the long chain fatty acids compete with oxalate to bind to calcium.
- Fat malabsorption results in saponification, formation of calcium soaps and free unbound oxalates.
- When larger amounts of free unbound oxalate reach the colon, they are absorbed and excreted in the urine (hyperoxaluria) which puts the patients at risk for kidney oxalate stones (a condition known as enteric fat malabsorption and enteric hyperoxaluria).
Free bile salts also alters the permeability of intestinal epithelial barriers (which then favours oxalate absorption).
- There is also a change in intestinal flora, Oxalobacter formigenes (a commensal anaerobic bacteria in the intestine) that normally metabolize oxalic acid.
- A lack of colonization with O. formigenes have been associated with increased dietary oxalate absorption, increased urine oxalate levels and calcium oxalate stones.
- Post operatively hence there is increased urinary oxalates (hyperoxaluria), low urine citrate (hypocitraturia), reduced urine volume and increased calcium oxalate supersaturation resulting in the formation of oxalate stones.
This condition is commonly treated by dietary restriction of oxalate rich food, increase oral fluid intake or oral calcium citrate tablets (a potent inhibitor of urinary crystallisation).
After surgery patients are often prescribed plenty of water and calcium citrate supplements (eg. 500mg in 3 doses, 1500mg/day) because calcium citrate has better absorption than calcium carbonate, helps prevent secondary hyperparathyroidism (less bone resorption) and binds to intestinal oxalates (less instestinal oxalate absorption and urinary secretion).
With bile salt malabsorption or alteration in the entero-hepatic circulation, there is also alteration in the cholesterol and bile salt balance in the liver or gall bladder resulting in gallstones formation.
Protein deficiencies after surgery may occur due to:
- Reduce consumption of protein foods.
- Reduced gastric capacity, rapid transit, reduced digestive enzymes and malabsorption .
It is recommended that patients have at least 50-60g of protein a day to prevent lean body muscle mass loss and in the first few weeks this may be in the form of protein fluid shakes (e.g.. Optifast).
The clinical consequences of malabsorption include:
- Diarrhoea, steatorrhoea (fatty stools) and fat soluble vitamin (A, D, E, K) deficiencies.
- Cholesterol gallstone formation (altered hepato-enteric circulation and reduced hepato-enteric bile acid secretion result in cholesterol supersaturation).
- Kidney oxalate stones formation.
- Lactic acidosis (carbohydrate meals leads to excess short chain fatty acid to colon which lowers colonic pH levels and increase Gram positive anerobes which produce lactate, humans lack lactate dehydrogenase and it is absorbed into the circulation.
Weight loss failure and weight regain in the long term
Most of the excess weight loss (EWL) occurs in the first 6 to 12 months after bariatric surgery.
Successful weight loss in the long term is defined as someone achieving greater than 50% EWL.
Interventional or operative weight loss failure has been defined as someone who only managed to achieve less than 25% EWL (a conservative definition) or less than 50% EWL (a more practical definition) in the long term.
There is a propensity for weight regain 2 to 3 years after surgery regardless of the what type of bariatric surgery performed (gastric band, sleeve or bypass).
Weight regain in the long term occurs because of various reasons which include:
- Operative or technical problems (remnant gastric pouch dilatation and loss of restriction resulting in increasing meal size) (ie. issue with meal portion).
- Compliance problems (poor adherence to dietary guidelines, return to high calorie, high GI index carbs and fatty food and lack of physical activity) (ie. issue with meal choices and sedentary behaviour).
- Behavioural problems (after a honeymoon period there is a relapse of eating disorder).
- Hormonal problems (lack of distal gut hormone post prandial satiety effect or grazing behaviour which may be an adaptive response to reactive hypoglycaemia or dumping syndrome) (ie. issue with dietary habits).
- Drug or alcohol dependence (ie. previously undiagnosed pre-existent or new post op psychological issues).
Inadequate weight loss (<25-30% EWL) at 6 months may predict inadequate weight loss result or failure after 24 months.
- Early dietary intervention and a physical training program will assist this group to restore weight loss.
Those losing >45% EWL at 6 months more likely to continue to lose weight up to 24 months and remain in the successful (>50% EWL) group.
Body contour deformities
Body contour deformities occurs due to skin excess and residual adiposities which often causes annoying problems such as hygiene issues, intertrigo, skin maceration as well as being a mechanical limitation to physical activities.
Cosmetic surgical correction may be needed.