Obesity in surgery

OBESITY IN SURGERY
By
DR. AZUMAH, Emmanuel Kalu
Department of Surgery
University of Nigeria Teaching Hospital,
Enugu, Nigeria

OUTLINE
• Introduction
• Statement of Surgical Importance
• Definition of Terms
• Relevant Anatomy & Physiology
• Aetio-pathogenesis
• Epidemiology
• Body mass index & Classification
• Comorbidities
• Pre, Intra & Post- operative
Considerations
• Treatment of Obesity
 Non-Operative
 Eligibility criteria
 Surgical options
• Complications
• Conclusion
OBESITY IN SURGERY by Dr. Azumah, Emmanuel Kalu
UNTH-Enugu

INTRODUCTION
• Obesity is defined as excess accumulation of fat in the body
• Objective measured and assessed as Body Mass Index
>30kg/m2
• Body weight in excess of 120% of the Ideal Body weight of
the individual
• Waist hip ratio >0.85 in females and > 0.90 in males
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STATEMENT OF SURGICAL IMPORTANCE
• Obesity exposes surgical patients to increased
morbidity and mortality
• Obesity increases the technical difficulty of surgery to
the surgeon and anaesthetist
• Surgery also provides an important treatment option
for the correction of obesity
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DEFINITION OF TERMS
• Ideal Body Weight is the believed to be maximally healthful for a
person, based chiefly on height but modified by factors such as gender,
age, build, and degree of muscular development
• Waist-hip ratio: waist circumference at midpoint between lowest rib
and iliac crest:
- widest circumference around the hips
• Lean Body Weight: difference between total body weight and body
fat. It is the weight of all body organs except fat
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DEFINITION OF TERMS
• Body mass index: Weight in Kg/ (Height in metres)2
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CLASSIFICATION
Body Mass Index in Kg/m2
Under-weight Normal Over-weight Obese Morbid-obesity Super-obesity
<18.5 18.5 – 24.9 25 – 29.9 ≥30 ≥35 or ≥40 ≥50
*Morbid Obesity BMI > 40kg/ m2 or >35kg/m2 in the
presence of obesity related comorbidity
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RELEVANT ANATOMY AND PHYSIOLOGY
• Aim of surgery is to restrict amount of food the patient can eat
• Some of the procedure add some element of gastric and small
intestinal bypass to produce some degree of malabsorption
• Neuromodulation approaches target the vagus or gastric muscle to
produce easy satiety
• Stomach fundus produces ghrelin – a hormone that stimulates
appetite
• Level of ghrelin drops during meals and increase in between meals
• Other hormones produced by the GIT which stimulate insulin release
and reduce appetite include GLP-1, peptide-YY and CCK
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AETIO-PATHOGENESIS
• Genetic predisposition
• Eating disorders
• Psychological problems
• Poor diet
• Lack of exercise
• Comorbidities
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EPIDEMIOLOGY
• 2nd most preventable cause of death after cigarette
smoking
• UK – 2%F: 0.8%M
• Higher incidence in US
• It decreases life expectancy (2.4 years)
• Predisposes to medical and surgical diseases
in both children and adults
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COMORBIDITIES
• Central Nervous System (CNS)
– Depression
• Cardiovascular Vascular System (CVS)
– Hypertension
– Hyperlipidaemia
– Arrythmia
– cardiomyopathy
– Ischaemic Heart Disease
• Respiratory System (RS)
– Reduced Functional Residual & Total Lung Capacities
– Asthma (usually a wheeze due to airway closure)
– Obstructive Sleep Apnoea
– Atelectasis
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• Gastrointestinal system
– Dyspepsia
– Peptic Ulcer Disease
– Reflux
– fatty liver
– steatohepatitis
– cirrhosis
– Hiatus hernia
• Genitourinary system
– Infertility
• Circulatory system
– Venous Thrombotic Events
– Varicose veinss
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• Musculoskeletal skeletal
– Blount’s Disease
– Slipped capital femoral epiphyses
– Osteoarthritis
– Degenerative spine disease
• Endocrine System
– Type-2 Diabetes Mellitus
– Dislipidaemia
– metabolic syndrome
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PRE-OPERATIVE ASSESSMENT
• History:
• During history taking ascertain presence of diagnosed medical
conditions/co-morbidities eg episodes of apnoea, snoring, daytime snoring
suggests OSA
• Ask for symptoms of associated medical conditions
• Past Surgical and anaesthetic history
• Medications eg. amphetamine stimulate appetite but increase peri-op
cardiac risk
• Social history of smoking and alcohol or drug abuse which can compound
challenges
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• Examination should reveal comorbidities where present
• Record weight, height and BMI
• Fat distribution
– Central fat is metabolically active unlike peripheral and contributes significantly to morbidity
• Cardiovascular system
– vital signs
– Ensure appropriate cuff size is used for BP measurement
• Test ability to tolerate supine position
• Respiratory system
– access airway using mallampati, thyromental distance, incisor gap, neck circumference, ability to
sublux the mandible
– Assess cardiopulmonary reserves
– Respiratory wheeze at rest
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• Investigations should be thorough and seek out undiagnosed or expose severity
of diagnosed illnesses
Basic
– FBC
– electrolyte & urea
– blood sugar
Other investigations
– chest radiographs
– ECG
– echocardiography (cardiovascular complications)
– Arterial Blood Gases (OSA)
– Arterial saturation < 95% on air
– PT/INR OBESITY IN SURGERY by Dr. Azumah, Emmanuel Kalu
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• Identify complications resulting from co-morbidities and treat as indicated
• Good peri-op sugar control
• Difficulty in assessing patient eg. Masses may be masked by fat
• Difficulty in transporting patient for pre-op investigations
• Difficulty in venous canulation
• Pre-op DVT prophylactic measures
• Admit close to surgery0
• Encourage mobilization
• TED Stockings
• LMWH
• Prophylaxis with PPI, H2 receptor antagonist to reduce risk of gastro-
oesophageal reflux and gastric aspiration
• When possible delay surgery till after patient has lost some weight
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PRE-OPERATIVE PREPARATION
• Adequate counselling
• Consent form should include increased risks of surgery attributable to obesity
• Consultant Anaesthetist review prior to surgery for optimal outcomes
• Notify theatre staff of patient and needs for adequate preparation
• Appropriate sized gowns
• Adequate number of theatre staff
• Appropriate monitoring equipment
• DVT Prophylaxis
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INTRA-OPERATIVE CONSIDERATIONS
• Anaesthesia
– Positioning for intubation
– Pre-oxygenation
– Airway management
– Vascular access
– Drug dose
 75% normal dose for epidural & subarachnoid block
– Needle size for regional anaesthesia
 loss of anatomical landmarks
 increased movement of skin
 difficulty locating the midline
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INTRA-OPERATIVE CONSIDERATIONS
• Trained and experienced staff present in theatre
• Transferring patient to operating table
• Positioning on table with head up tilt
• Operating table size/maximum weight
• Venous and arterial cannulation
• Tourniquet use
• Cleaning and draping
• Electrocautery
• Access to operative site
• Wound closure
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POST-OPERATIVE CONSIDERATIONS
• Extubate when awake and in sitting position
• Humidified oxygen in first 24 Hours
• Monitored with pulse oximeter in recovery room and ward
• DVT & PE prophylaxis and Early mobilization
• Chest Physiotherapy
• Look out for early signs of surgical site Infection and wound dehiscence
• Positioning to prevent aspiration
• Avoid NSAIDS in those with renal dysfunction & DM Nephropathy
• Prevention of bedsores
• Avoid IM injections as absorption can be unpredictable
• Look out complications from comorbid conditions
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TREATMENT OF OBESITY
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NON-OPERATIVE
• Food Addiction
– Psychological Component
– Physical Component
– Group Therapy & Support
• Behavior Modification
– Eat 3 times per day
– No Snacking Between Meals (Water Only)
– No Eating after 7:00 pm
• Lifestyle Changes
– Walk one half hour per day (Continuous)
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ELIGIBILITY CRITERIA FOR SURGERY
• Acceptable Operative Risk for Surgery
• Failure of conservative treatment (Diet & Exercise)
• BMI >40;
• BMI > 35 with obesity related comorbidities
• Minimum of 5years obesity
• No Psychiatric Contraindications
• Avoid if likely to get pregnant within 2 years
• Realistic Commitment and Expectations
• Age limits 18 – 55 years (relative)
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WORLDWIDE
• 468,609 Bariatric Surgeries performed
worldwide (2013)
• 95.7% carried out laparoscopically
• 32.9% in the USA
• 45% Roux-en-Y
• 37 % Sleeve Gastrectomy
• 10% Adjustable Gastric Banding
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BARIATRIC SURGERY
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• Rationale for Bariatic Surgery-
• To prevent comorbidities
• Increase life expectancy
• Reduce healthcare costs
not cosmetic surgery
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SURGICAL OPTIONS:
GASTRIC BANDING:
• Half of all surgical procedures
• Adjustable gastric band applied
around upper stomach
• Degree of restriction controlled
amount of fluid injected into the port
• Popular in Australia
• Least risky procedure (peri-op
mortality <0.1%)
• Performed on patients with BMI of
<50
• Loses 45 – 50% excess body weight
Complications
• Band prolapse
• Band slippage
• Band erosion into stomach
• Continual band adjustments
• Band revision procedure
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SLEEVE GASTRECTOMY
• Relatively new procedure
• Not require any adjustment
• Relative mortality of 0.2%
• Removes most ghrelin-secreting area of
stomach
• Loses 65% of excess weight
• Tendency of sleeve expansion
• Preferred in patient with BMI >50
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ROUX-EN-Y GASTRIC BYPASS:
• Very effective weight loss procedure
• Myriad of technical variations
• Higher risk with peri-op mortality of
0.5%
• Losses excess weight of 65 -70%
• Resolves >80% type-2 DM
• Need for post-op follow-up to avoid
deficiency syndromes eg. Multi-vit,
calcium, iron
• Periodic bone densiometry to avoid
premature osteoporosis
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Biliopancreatic Diversion (BPD)
(+/- duodenal switch)
• Produces the most malabsorption than
others
• Need for high protein intake
• Requires vitamin and micronutrient
supplementation
• Effective in patients with very high BMI
• Losses 75 – 85% excess weight
• Alleviates DM
• Highest peri-op mortality of 1 – 2 %
• Duodenal switch variation reduces
need for vit B12 intake and incidence
of anastomotic stricture at the GJ-
anastomosis
• Standard BPD involves removal of 2/3
distal stomach
• Duodenal switch variation involves
vertical sleeve gastrectomy
• Anastomosis is made to 1st part of
duodenum rather than stomach as in
standard BPD
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COMPLICATIONS
• General:
• Bleeding
• Seroma
• Haematoma
• Fat necrosis
• Infection
• Wound dehiscence
• DVT ± PE
• Bowel perforation
• Peri-operative mortality
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COMPLICATIONS
• Specific procedure:
• Internal herniation (Gastric band, BPD)
• Staple line/anastomotic leak (gastric bypass, sleeve gastrectomy & BPD)
• Band slippage/erosion
• Pouch dilatation (gastric band, gastric bypass & sleeve gastrectomy)
• Long-term:
• Protein calorie malnutrition
• Vitamin & micronutrient depletion syndromes
• Weight regain
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CONCLUSION
• Obesity has inherent medical risks which increase morbidity
and mortality in surgery
• Poses mechanical and technical challenges that must also be
anticipated and planned for
• Often requires multi-disciplinary management
• Operative options are available and have better outcomes
for the treatment of the morbidly obese
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