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RATIONALE FOR THE SURGICAL TREATMENT OF SEVERE OBESITY
INTRODUCTION
There is considerable misinformation concerning the validity of
bariatric surgery in the management of morbid obesity. The
following “Rationale for Surgery” covers the field in general.
References are provided to allow the interested reader to obtain
more detailed information along with the opportunity to examine
the original data on which these statements are based.
Bariatric surgery is a recognized sub-interest in the field of
General Surgery. It has been endorsed by the National Institutes
of Health Consensus Conference, 1992.1 The American Society for
Bariatric Surgery is a section of the American College of
Surgeons and a specialty surgical society in the Specialty &
Service Society section of the American Medical Association.
Regular members of the A.S.B.S. are all Board Certified Surgeons
who have a special interest in surgical treatment of hugely
obese patients. It must emphasized that these procedures are in
no way to be considered as cosmetic surgery, and, as you read
on, this should become abundantly clear.
Among recent articles of interest included in the references are
the paper from Pories et al from the University of East
Carolina, a group with the finances and personnel to enable
follow-up their entire obesity surgery population, some 600
patients, achieving a patient follow-up of 96% at 14 years after
surgery. This paper, while particularly emphasizing the
beneficial effects of surgically induced weight loss in Type II
diabetics, also includes follow-up data on other aspects of
their series.(2) Other papers detailing the results of bariatric
surgery in the younger and older age groups and noting
improvement in co-morbidities not generally appreciated include
results in adolescents,(3) those over 55 years of age,(4) and
the remarkable improvements in asthmatics which follows
surgically induced weight loss.(5)
RATIONALE FOR THE SURGICAL TREATMENT OF SEVERE OBESITY
Clinically severe obesity (this term is now preferred over
morbid obesity) is a disease of excess energy stores in the form
of fat. Clinically severe obesity correlates with a Body Mass
Index (BMI) of 40 kg/m2 or with being 100 pounds overweight.
Being overweight is associated with real physical problems which
are now well recognized. The most obvious is an increased
mortality rate directly related to weight increase.6 In a 12
year follow-up of 336,442 men and 419,060 women, it was found
that the mortality rates for men 50% above average weight were
increased approximately two fold. In the same weight group the
mortality was increased five fold for diabetics and four fold
for those with digestive tract disease. In women, the mortality
was also increased two fold, while in female diabetics the
mortality risk increased eight fold and three fold in those with
digestive tract disease. It is clear that overweight people of
both sexes, especially young overweight people, tend to die
sooner than their lean contemporaries.7,8 While obesity, of
itself, is a risk factor,9 most associated mortality and
morbidity is associated with the co-morbid conditions. This
applies to non-operated as well as peri-operative mortality and
morbidity. These conditions have been outlined in the 1985
National Institutes of Health Consensus Conference and include
hypertension, hypertrophic cardiomyopathy, hyperlipidemia,
diabetes, cholelithiasis, obstructive sleep apnea,
hypoventilation, degenerative arthritis and psychosocial
impairments.10
A Veterans Administration study of 200 morbidly obese men aged
23 to 70 years, with an average weight of 316 lbs (143.5 kg)
showed a twelve fold increase in mortality in the 25-34 year age
group and a six fold increase in the 35-44 year age group.
During the average follow-up period of 7 ˝ years, 50 of the
original group had died.5 An interesting ongoing study in this
regard is the Swedish Obesity Study (SOS) in which 2000 patients
have been randomized to diet therapy and gastric restrictive
surgery.12 The study is still incomplete, but at this time, 6
years into the study, 3 “surgical” patients have died, and 27
“diet” patients have died, a 9 fold difference.
The Nurses Health Study has reported obesity related health
risks in women at much less impressive degrees of obesity.
Weight gain after the age of 18 years was shown to be a strong
predictor of cardiovascular risk. This large prospective cohort
study involving 115,886 women apparently healthy at baseline,
showed a strong association between BMI and cardiovascular
disease. As compared with women whose BMI was less than 21
Kg/m2, the age and smoking adjusted relative risk of non-fatal
myocardial infarction and fatal coronary artery disease for
women with BMI of 25-29 was 1.8 (95%CI: 1.2-2.5), and that for
women with BMI 29 was 3.3 (95%CI:2.3-4.5).13
The Framington study noted that the first cohort to terminate
because of demise of all participants was the morbidly obese.
Finally, in this litany of risk, the Guinness Book of Records
memorializes the worlds heaviest individuals. Note that none of
these lived over 40 years of age. Recent work has demonstrated
that the significantly increased mortality risk of morbid
obesity reverts to normal following successful weight loss
surgery.14
Obesity is dangerous to health because of the associated
increased prevalence of cardiovascular risk factors such as
hypertension, diabetes mellitus, hypertriglyceridemia,
hyperinsulinemia and low levels of high density lipoprotein (HDL)
cholesterol. Cardiovascular risk factors are reduced
significantly by sustained weight reduction. Data from the
Framingham study support the estimate that a ten percent
reduction in body weight corresponds to a twenty percent
reduction in the risk of developing coronary heart disease.15
Serious consequences of severe obesity are well documented and
include cardiac dysfunction, pulmonary problems, digestive
diseases, and endocrine disorders as well as obstetric,
orthopedic, and dermal difficulties.
The association between average weight of population groups and
the prevalence of non-insulin-dependent diabetes has been
repeatedly observed.16,17 The risk for diabetes has been
reported to be about twofold in the mildly obese, fivefold in
moderately obese and tenfold in severely obese persons.18 The
duration of obesity is a more important determinant of the risk
for developing diabetes.19 In cross-sectional studies, obesity
has been shown to be associated an increased prevalence of
non-insulin-dependent diabetes in both men and women.20,21 The
NHANES II data found that the overall relative risk of
developing diabetes was 2.9 times higher for obese persons who
are 20-75 years old.22 The risk of developing diabetes also
increases with age,23-25 if a family history is present26 and if
the obesity is central.27 A prospective study in Scandinavia
showed that moderate obesity was associated with a 10 fold
increase in the risk of diabetes. This risk increased sharply as
obesity became more severe.27
Cancer mortality rates are increased in severely obese females;
e.g. endometrium (5.4 times), gallbladder (3.6 times), uterine
cervix (2.4 times), ovary (1.6 times), breast (1.5 times).
Cancer mortality rates are increased in severely obese males;
e.g. colorectum (1.7 times), and prostate (1.3 times).28
Health care for the four million severely obese adults in the
United States of America (eighty percent of whom are women of
childbearing age)29 has been hampered by the misconception that
body weight is not a physiologically regulated variable, but
rather determined by aquired food habits and conscious and
unconscious desires. Obesity represents a management challenge
for physicians and a psychological and biological challenge for
patients.
Lack of respect for the severely obese is an issue of concern. A
survey of severely obese individuals found that nearly eighty
percent reported being treated disrespectfully by the medical
profession. There are widespread negative attitudes that the
severely obese adult is weak-willed, ugly, awkward,
self-indulgent and immoral. This intense prejudice cuts across
age, sex, religion, race, and socioeconomic status. Numerous
studies have documented the stigmatization of obese persons in
most areas of social functioning. This can promote psychological
distress and increase the risk of developing a psychological
disorder. The severely obese patient is at risk for affective,
anxiety and substance abuse disorders. The obese often consider
their condition as a greater handicap than deafness, dyslexia or
blindness.30,31
NON-OPERATIVE TREATMENT:
Published scientific reports document that non-operative methods
alone have not been effective in achieving a medically
significant long term weight loss in severely obese adults. The
average medical weight reduction trial is a 10-12 week study
with average weight loss of 2.5 kg.32 The use of anorectic
medications has recently been advocated as a long term
therapeutic modality in management of what is clearly a chronic
disease. In a nearly four year study, utilizing a two drug
regimen of Phentermine and Fenfluramine, behavior modification,
diet and exercise, the initial optimistic results have not been
sustained, with a one third drop out rate and a final average
weight loss of only three pounds in those who were followed for
the four years of the study.33 This drug combination appears to
have an unacceptably high association with cardiac valvular
disease and is no longer recommended. Dietary weight loss
attempts often cause depression, anxiety, irritability, weakness
and preoccupation with food. The treatment goal for severe
obesity should be an improvement in health achieved by a durable
weight loss that reduces life threatening risk factors and
improves performance of activities of daily living. Temporary
fluctuations of body weight from effective calorie restricted
diets should be avoided.
TREATMENT GOALS:
Surgical treatment is medically necessary because it is the only
proven method of achieving long term weight control for the
severely obese. Surgical treatment is not a cosmetic procedure.
Surgical treatment does not involve the removal of adipose
tissue (fat) by suction or excision. Bariatric surgery involves
reducing the size of the gastric reservoir, with or without a
degree of associated malabsorption. Eating behavior improves
dramatically.34 This reduces caloric intake and ensures that the
patient practices behavior modification by eating small amounts
slowly, and chews each mouthful well. Success of surgical
treatment must begin with realistic goals and progress through
the best possible use of well designed and tested operations.
These have been worked out over the last thirty years, and are
now standardized, clearly defined procedures, with well
recognized and documented outcome results.
Prevention of secondary complications of severe obesity is an
important goal of management. Therefore, the option of surgical
treatment is a rational one supported by the time honored
principle that diseases that harm call for therapeutic
intervention that harms less. The biological basis for severe
obesity is unknown, though recent work has demonstrated a
genetic component of between 25 and 50%, and several studies
confirm the influence of genetically determined proteins
produced by the fat cell which have a place in the control of
satiety. This confirms that morbid obesity is a disease, not a
disorder of willpower, as sometimes implied. The physiologic,
biochemical and genetic evidence is overwhelming that clinically
severe obesity is a complex disorder of energy metabolism. The
contributing causes are inheritance, environmental, cultural,
socioeconomic and psychological.
PATIENT SELECTION:
The option of surgical treatment should be offered to patients
who are well informed, motivated, and acceptable operative
risks. The patient should be able to participate in treatment
and long term follow-up. Some patients with manifest
psychopathology that jeopardizes an informed consent and
cooperation with long term follow up may need to be excluded. A
decision to elect surgical treatment requires an assessment of
the risk and benefit in each case. Increased abdominal fat is an
important risk factor associated with the major complications of
obesity. Functional impairments associated with obesity are also
important deciding factors for surgical treatment. An important
conclusion of the 1991 National Institutes Consensus Development
Conference Statement on the surgical treatment of obesity was
that patients judged by experienced clinicians to have a low
probability of success with non-surgical measures, as
demonstrated, for example, by failure in established weight
control programs or reluctance by the patient to enter such a
program, may be considered for surgical treatment.1
Patients whose BMI exceeds 40 are potential candidates for
surgery if they strongly desire substantial weight loss, because
obesity severely impairs the quality of their lives. They must
clearly and realistically understand how their lives may change
after operation.
In certain circumstances, less severely obese patients (with
BMI’s between 35 and 40) also may be considered for surgery.
Included in this category are patients with high risk co-morbid
conditions such as life threatening cardiopulmonary problems
(e.g. severe sleep apnea, Pickwickian syndrome, obesity related
cardiomyopathy, or severe diabetes mellitus). Other possible
indications for patients with BMI’s between 35 and 40 include
obesity-induced physical problems that are interfering with
lifestyle (e.g. musculoskeletal or neurologic or body size
problems precluding or severely interfering with employment,
family function and ambulation).
End stage obesity syndrome: Some candidates for surgical
treatment of severe obesity have such impaired health that they
must be hospitalized pre-operatively and undergo treatment to
improve their operative risk.
RISKS OF SURGICAL TREATMENT:
Assessing the risks of surgical treatment of obesity involves
operative, perioperative and long term complications. Available
published series report that the immediate operative mortality
rate for both vertical banded gastroplasty and Roux-en-y gastric
bypass is relatively low. Morbidity in the early postoperative
period, i.e. wound infections, dehiscence, leaks from staple
breakdown, stomal stenosis, marginal ulcers, various pulmonary
problems, and deep thrombophlebitis may be as high as ten
percent or more. Splenectomy is necessary in 0.3% of patients to
control operative bleeding.(In my series 6/4000 = 0.15%)
However, the aggregate risk of the most serious complications of
gastrointestinal leak and deep venous thrombosis is less than
one per cent. In the late postoperative period, other problems
may arise and may require reoperation. The mortality and
morbidity rates of reoperation are higher than those of primary
operations.
THE INTERNATIONAL BARIATRIC SURGERY REGISTRY (ISBR)
The National Bariatric Surgery Registry (NBSR), [now the
International Bariatric Surgery Registry (ISBR) ] 1992-3 Winter
Pooled Report indicates the following:
Ten deaths occurred within 40 days of operation in 7415
patients, a 0.13% mortality rate.
A subset of 4949 patients with complete information for
complications and postoperative hospital stay showed:
Females comprised 87% of the data set.
Median values were determined for
Age, years 37 (Range 18-70 years)
Weight, kg 121 (Range 77-288 kg)
lbs 266 (Range 165-633 lbs)
Body Mass Index (BMI) 44 (Range 29-91 kg/m2)
No postoperative complications 91.33%
Median hospital stay 4.8 days
Deep venous thrombosis 0.2%
Gastrointestinal leak 0.1%
Subphrenic abscess 0.1%
Respiratory complications 3.2%
Wound infection 1.1%
Risk and efficacy of operations for obesity must be understood
in the context that severe obesity is a chronic, frequently
progressive, life threatening disease. The therapeutic program
applied should be designed to last throughout the lifetime of
the patient.
RESULTS:
Weight loss usually reaches a maximum between 18 and 24 months
postoperatively.
Mean percent excess weight loss at five years ranged from 48 to
74 % after gastric bypass and from 50 to 60% after vertical
banded gastroplasty. In a study of over 600 patients, with 96%
follow-up, mean percent excess weight loss still exceeds 50%
fourteen years following gastric bypass.2 Another 10 year
follow-up series from the University of Virginia reports weight
loss of 60% of excess weight at 5 years and in the mid 50's
between years 6 and 10.35 Multiple other authors have reported 5
and 6 year follow-up of their patient series with similar weight
loss results.2,15,36-40
Weight reduction surgery has been reported to improve several
comorbid conditions such as glucose intolerance and frank
diabetes mellitus,2 sleep apnea and obesity associated
hypoventilation,41,42 hypertension,43 and serum lipid
abnormalities.44,45 A recent study showed that Type II diabetics
treated medically had a mortality rate three times that of a
comparable group who underwent gastric bypass surgery.46 Also
preliminary data indicate improved heart function with decreased
ventricular wall thickness and decreased chamber size with
sustained weight loss. Other benefits observed in some patients
after surgical treatment include improved mobility and stamina.
Many patients note a better mood, self esteem, interpersonal
effectiveness, and an enhanced quality of life. They have
lessened self consciousness. They are able to explore social and
vocational activities formerly inaccessible to them. Self body
image disparagement decreases. Marital satisfaction increases,
but only if a measure of satisfaction existed before surgery. If
marital discord exists preoperatively, the improved self image
may lead to divorce postoperatively.47
Evolving surgical techniques have resulted in progressive
improvement in both the safety and long term integrity of
bariatric surgical procedures. Previous reports of staple line
failures of 15% or more in ten years13 has resulted in
increasing use of gastric transection. In consequence, the need
for revisional surgery to correct this problem48,49 has all but
disappeared.
Only the further accumulation of long term follow up data will
answer the question of what magnitude of weight loss is
necessary to achieve the greatest benefit in terms of longevity.
Data from medical weight reduction studies suggests that a small
weight loss will favorably affect obesity comorbidity.
Similarly, data in patients over 55 years of age at the time of
surgery, followed at least 6 years after gastric bypass, reflect
significant sustained improvement in morbidity.4
CHILDBEARING:
Women of childbearing age who elect to have weight reduction
operations must use secure birth control methods during the
period of rapid weight loss. They should be informed that
maternal malnutrition may impair normal fetal development. This
is particularly important to those who may have previously
failed to conceive, since fertility may increase following
weight loss. Indeed, failure to conceive in the face of morbid
obesity is yet another positive indication for weight loss
surgery. Women who become pregnant after these surgical
procedures need specific attention from the surgical care team.
However, there are several reports in the literature of
pregnancy outcomes following gastric bypass without evidence of
fetal impairment.50
NUTRITIONAL CONSEQUENCES OF GASTRIC RESTRICTIVE SURGERY FOR
OBESITY:
Gastric restrictive surgery in the motivated, cooperative
patient, who has been educated in the nutritional requirements
to maintain adequate protein/calorie/mineral/vitamin intake,
routinely results in a smooth post-operative course, with some
protein deficit in the first 3 postoperative months, which is
completely restored 18 months after surgery, by which time the
patient will have re-established a lean body mass appropriate to
the total body weight.
Pure gastric restrictive procedures such as vertical banded
gastroplasty (VBG), silicone ring vertical gastroplasty (SRVG),
adjustable silicone gastric banding (ASGB) all achieve weight
loss by restricting volume of intake. Intake becomes a function
of the patients motivation to chew well and eat slowly. Failure
to do so may result in repeated vomiting and isolated cases of
protein and vitamin deficiency have been reported in these
circumstances. Careful patient follow up is therefore mandatory,
with particular emphasis on the first three postoperative
months. Adjustable silicone gastric banding remains in FDA
trials and is not generally available in the USA at this time.
Gastric bypass with Roux-y results in ingested food bypassing
the gastric fundus, body, antrum, duodenum and a variable length
of proximal jejunum. In consequence, these patients are at risk
to develop iron deficiency secondary to lack of contact of food
iron with gastric acid and consequent reduced conversion of iron
from the relatively insoluble ferrous to the more absorbable
ferric form. In addition, vitamin B12 deficiency may result in
consequence of food no longer coming in contact with gastric
intrinsic factor. Vitamin D and calcium absorption may also be
reduced since the duodenum and proximal jejunum, which are the
preferential sites of absorption, are bypassed by this
procedure. Life long supplements of multivitamins, vitamin B12
and calcium are mandatory following this procedure. A corollary
of this is the need for long term follow up for physical,
nutritional and metabolic evaluation and counseling.
WHAT SPECIFIC RECOMMENDATIONS CAN BE MADE FOR THE TREATMENT OF
SEVERE OBESITY?
Patients seeking therapy for the first time should be evaluated
by a knowledgeable physician and provided with sufficient
information on which to make a reasonable choice for therapy.
In spite of the failure of medical therapy by drugs, diet,
behaviour modification and exercise to achieve documented long
term weight loss in the morbidly obese, it is accepted practice
to require that the potential candidate for surgical treatment
have made good faith attempts to achieve weight loss by dietary
means. Although the segment of the morbidly obese population
able to lose significant weight by non-surgical means is
miniscule, candidates for surgery must be given the opportunity
to try, a proposition which justifies insistence on at least one
attempt at dietary weight loss prior to acceptance into a
bariatric surgery program.
Decisions on what therapy to recommend to patients with
clinically severe obesity should depend on their wishes for
outcomes, on the need for therapy, and on the physicians
explanation of options for therapy and the current information
on probable safety, efficacy, advantages and risks. The need for
close nutritional monitoring during rapid weight loss and the
need for lifelong medical surveillance after surgical therapy
should be made clear to the prospective patient and their
relatives.
The operation should be carried out by a surgeon substantially
experienced with the appropriate procedures and working in a
clinical setting with adequate support for all aspects of
perioperative assessment and management. These include hospital
facilities geared to care for the morbidly obese patient,
medical specialty availability, psychological support, dietary
and nutritional counseling, and patient support groups.
PREOPERATIVE PSYCHOLOGICAL TESTING:
There are two possible reasons for pre-operative psychological
testing prior to bariatric surgery. One is to weed out those
with significant psychopathology in whom surgery would be
contra-indicated, the other to pre-select those in whom the
surgery is likely to be a success. Unfortunately psychologic
evaluation has proven of limited value in both these situations.
Studies of severely overweight persons conducted before their
undergoing anti-obesity surgery(1) have shown a) that there is
no single personality type that characterizes the severely
obese. b) that this population does not report greater levels of
psychopathology than do average-weight control subjects; and c)
that the complications specific to severe obesity include body
image disparagement and binge eating. Studies conducted after
surgical treatment and weight loss have shown 1) that self
esteem and positive emotions increase; 2) that body image
disparagement decreases; 3) that marital satisfaction increases,
but only if a measure of satisfaction existed before surgery;
and 4) that eating behavior is improved dramatically. The
results of surgical treatment are superior to those of dietary
treatment alone. Practitioners should be aware that severely
obese persons are subjected to prejudice and discrimination and
should be treated with an extra measure of compassion and
concern to help alleviate their feelings of rejection and
shame.51
In addition, numerous studies in the literature attempting to
identify patient characteristics related to outcome have been
reported, but no reliable psychological predictors of success
have been identified. (See Vallis and Ross 1993 52 for a
comprehensive review of this area). Only two general
recommendations emerge from this study. (1) The more distressed
patients are by their obesity , (reflected by exogenous
depression) the more likely they are to lose weight and (2)
Serious psychiatric disturbance, to the extent that psychiatric
treatment or admission is required, appears to be a negative
predictor of outcome. While other psychological variables have
been shown to be associated with post-surgical weight loss, none
have been replicated in independent studies.52
Accordingly the logical approach to the question of need for
routine pre-operative psychological evaluation is not to require
psychological evaluation in patients who have no history of
severe psychiatric disturbance or who are not currently under
the care of a psychologist/psychiatrist and who are not on
psycho-tropic medications. Those who are, on the other hand,
should be required either to have psychiatric clearance in
writing from their counselor or to undergo psychiatric
evaluation before surgery. Post-operative support can be
extremely important, especially for those with preoperative
psychological difficulties, and should be actively pursued by
patient, surgeon and psychologist/psychiatrist.
“Weight reduction may be life saving for patients with extreme
obesity, arbitrarily defined as weight twice the desirable
weight or 45 kg (100 pounds) over desirable weight”10
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