Obesity Risks inPlastic Surgery

Lip Teh

Plastic Surgery

December 2006

Obesity: The Epidemic

• In the US:– Annual deaths due to obesity:

112,000– 65% adults overweight

• 30% obese

• 4% severe obesity

– 16% of children ages 6 to 19 years old are overweight

– Obesity prevalence has increased across all education levels and is higher for persons with less education

Weight gain

• Fat is deposited throughout the subcutaneous and visceral areas fairly evenly

• Fat is initially accumulated in existing adipocytes

• When total body fat>40kg or BMI>35 then new fat cells are produced (hyperplastic obesity). This is more resistant to dieting and exercise.

Classification

Fat Distribution

• Limitation of BMI : does not provide a description regarding distribution of adipose tissue.

• Subcutaneous vs visceral fat mass.

• most accurate definition of fat distribution relies on the instrumental imaging (CT, MRI)

Central obesity

mainly located in the abdomimal viscera, whereas limbs and face are often normal.

frequently associated with metabolic and vascular disorders

requires dietological, exercise, and possibly psychological therapy.

Peripheral obesity

mainly located in limbs and in regions below navel

infrequently associated with metabolic disorder

Often resistant to dieting

Diffuse obesity

most common form consists of a

homogenous increase of adipose tissue in the whole body.

ideal therapy should be a synergic approach by the dietologist, the bariatric surgeon and the plastic surgeon.

Localised obesity

rare forms of obesity, such as Barraquer-Simons Syndrome, Madelung’s disease or Launaois-Bensaude syndrome and other lipodystrophic disorders,

resistant to the dietologist or bariatric surgery.

Formerly obese

redundant cutaneous mantle secondary to massive fat loss

Bariatric Surgery

• Indications:– BMI>40– BMI> 35 who have significant

comorbidities.

• most effective therapy for long-term significant weight loss in morbidly obese patients.

• number of procedures performed in the US increased 500% between 1993 and 2003.

Bariatric Surgery

• Metaanalysis of 22,000 patients

1. Lipid disorders improved in 70%

2. Diabetes improved in 76.8%

3. Hypertension improved in 78.5%

4. Obstructive sleep apnea improved in 86%

Buchwald et al, JAMA 2004

Obesity comorbidities• Hypertension• Dyslipidemia, Type 2 diabetes, Insulin resistance, glucose

intolerance, Hyperinsulinemia• Atrial fibrillation, Coronary heart disease, Congestive heart failure• Stroke• Reflux oesophagitis, Gallstones, Cholecystitis and cholelithiasis• Gout, osteoarthritis• Obstructive sleep apnea and respiratory problems• Malignancies - endometrial, breast, prostate, and colon cancer• Complications of pregnancy• Poor female reproductive health (such as menstrual irregularities,

infertility, and irregular ovulation)• Stress incontinence, Uric acid nephrolithiasis• Psychological disorders (such as depression, eating disorders,

distorted body image, and low self-esteem)

Obesity and Surgery

• Studies from multiple coronary artery bypass surgery shows:

– In hospital mortality unchanged compared to normal population

– Increased risk of perioperative morbidity, sternal infections, prolonged mechanical ventilation and increased length of stay

Obesity and Surgery

• DVT and PE– Mechanisms

• increased intra-abdominal pressure • venous stasis • hypercoagulable state (higher levels of factor VIII and

factor IX, but not of fibrinogen )• Poor mobility

– Relative risk (obese vs nonobese) Am J Med 2004• DVT – 2.5x • PE – 2.2x

– In obese(BMI>25) women on OCP – 10x risk of DVT (Thromb Haemost 2003)

Obesity and Surgery

• Nosocomial infection– 3x increase risk in obese– 4x increase risk in severe obese– Mostly due to increase in surgical site

infection– Also increase risk of pneumonia and UTI

Obesity and Surgery

• Surgical site infection

– Mechanisms• decreased oxygen

tension • immune impairment • tension along suture

line• longer operative time

– Relative risk = 2-3x

Surgical Site infection

• Obesity Research 2003– Prospective study of 395 patients in a general

surgery unit

Underweight Normal Overweight Obesity Extreme Obesity

Clean 0/5 (0%) 7/60 (12%) 25/168 (15%) 21/46 (46%) 4/6 (67%) Clean/contaminated 0/2 (0%) 4/15 (27%) 4/40 (10%) 6/6 (100%) Contaminated 0/2 0%) 10/18 (56%) 13/20 (65%) 2/2 (100%) Dirty 0/2 (0%) 0/1 (0%) Total 0/9 (0%) 19/95 (20%) 44/230 (19%) 29/55 (53%) 4/6 (67%)

Surgical Site infection

• Olsen, J Thorac Cardiovasc Surg 2002– Retrospective study– Obesity: OR 3.1x for superficial surgical-site

infection

• Vilar-Compte (World J Surg 2004)– Prospective study, 280 patients in a breast

oncological surgery unit– Obesity: OR 2.5x for surgical site infection

Surgical Site infection

• Barber (Arch Surg 1995)– MSKC oncological service N=1226– Surgical site infection rates were 3.8% in

class I; 8.8% in class II; 20.7% in class III; and 46.9% in class IV procedures.

– obesity contributed as strongly as the surgical procedure category to a patient's likelihood of acquiring a surgical site infection.

Obesity and Breast Reduction

• Only 20% of women undergoing reduction mammoplasty are of normal weight

• Strombeck 1964– systemic and local complications

• 4.4% for the nonobese • 13.5% for those > 10 kg overweight.

• Zubowski (PRS 2000; retrospective n=395)– Major local complications (skin loss, nipple loss,

abscess, and hematoma )• 6.2% for the nonobese • 9.2% for those > 10 kg overweight.

– Complications correlated with increasing weight of reduction

Obesity and Breast Reduction

• Platt (Ann Plast Surg 2003 prospective n=30)– BMI > 26.3, 33% wound breakdown rate– BMI < 26.3, 10% wound breakdown rate; P < 0.05

• Wagner (PRS 2005, retrospective n=186)– no increase in the complication rate in the obese

patients• O’Grady (PRS 2005, retrospective n=133)

– BMI not associated with nipple necrosis, hematoma formation, fat necrosis, cyst formation, nipple sensation, or hypertrophic scarring

– Higher BMI predicted a delayed healing, wound dehiscence, and infection. (relative risk 1.2x)

Obesity and Breast Reduction

SummaryIn reduction mammaplasty, obesity leads to an

increased risk (1.5-3x) of

1. delayed healing

2. wound dehiscence

3. infection– Stronger correlation with size of reduction

Obesity and TRAM

• Paige, Bostwick PRS 1998– Pedicled TRAM, retrospective n=257– Obesity significantly associated with

• Donor site complications• Fat necrosis• Partial flap loss• Breast mound infection

Obesity and TRAM

• Chang PRS 2000– Free TRAM, retrospective n=939 flaps (718 patients)– Flap complications: Obese vs normal weight

1. overall flap complications (39.1 vs 20.4%;p = 0.001),2. total flap loss (3.2 versus 0%;p = 0.001)3. flap seroma (10.9 versus 3.2%;p = 0.004)4. mastectomy flap necrosis (21.9 versus 6.6%;p = 0.001).

– Flap complications: Overweight vs normal weight 1. overall flap complications (27.8 versus 20.4%;p = 0.033)2. total flap loss (1.9 versus 0%p = 0.004)3. flap hematoma (0 versus 3.2%;p = 0.007)4. mastectomy flap necrosis (15.1 versus 6.6%;p = 0.001)

Obesity and TRAM

– Donor complications: Obese vs normal weight 1. overall donor-site complications (23.4 versus 11.1%;p =

0.005)

2. infection (4.7 versus 0.5%;p = 0.016)

3. seroma (9.4 versus 0.9%;p <0.001)

4. hernia (6.3 versus 1.6%;p = 0.039).

– Donor complications: Overweight vs normal weight 1. overall donor-site complications (19.8 versus 11.1%;p =

0.003)

2. infection (2.4 versus 0.5%;p = 0.039)

3. bulge (5.2 versus 1.8%;p = 0.016)

4. hernia (4.3 versus 1.6%;p = 0.039)

Obesity and TRAM

• Moran PRS 2001– Free vs Pedicled TRAM, retrospective n=114– no significant difference in the overall complication

rates – Free TRAMs: 14% of nonobese, 17% of moderately

obese, and 33% of severely obese (p=0.08)– Pedicled: 27%, 37% and 29% (not significant)– Overall, free TRAM flap reconstructions had a lower

incidence of partial flap loss.• enhanced blood supply, dominant DIEA vessel• more freedom in positioning the flap

Obesity and TRAM

• Wang PRS 2005– Retrospective study n=107, delayed pedicle– nonflap complications increased with

increasing obesity (8 vs 31.6%)– no difference in flap related complications

between obese and nonobese groups after delayed pedicled TRAM

Obesity and TRAM

Summary

• In TRAM reconstructions, obesity leads to an increased risk of

1. Flap complications (2x)

2. Donor site complications (2x)

3. Systemic complications

• Risks reduced with free TRAM or delayed pedicled TRAM

Obesity and Abdominoplasty

• Vastine (Ann Plast Surg 99)– Retrospective study, n=90– 80% of obese patients had complications

compared with the borderline and nonobese patients, who had complication rates of 33% and 32.5% respectively

– Previous gastric bypass surgery had no significant effect on the incidence of postabdominoplasty complications.

Obesity and Body Contouring

• Taylor (Obese Surg 2004)– Retrospective study, n=30 post massive

weight loss– Overall morbidity 42%

• 20% wound breakdown• 17% seroma• 1 patient died from PE

– Challenging surgery requiring individualized approaches with intensive follow-up.

Obesity and Body Contouring

• Sanger (Ann Plast Surg 2006)– Retrospective study, n=26 post massive

weight loss– 27% wound complications(seromas,

hematoma, infection, and fat necrosis)– increase in wound complications attributed to

the inherent complications seen with obese patients.

Obesity and Body Contouring

Summary

• Preliminary evidence suggests that incidence of local complications in body contouring operations remain unchanged despite weight loss.