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SEATTLE,
WA— Medically complicated (morbid) obesity affects
six per cent of women and two per cent of men in the United States,
and has medical, quality-of-life and economic implications of staggering
proportions. Since dietary, exercise and pharmacological methods
have a low success rate in achieving and maintaining long-term weight
reduction, several types of surgical operations have been developed,
all of which have associated complications.
“Any major surgical procedure in patients who are seriously
overweight carries risks, but an experienced bariatric surgeon can
perform these operations with a minimum of complication,” Joseph
M. Vitello, MD, said at the annual meeting of the American College
of Gastroenterology. “And in view of the many comorbid conditions
many obese people have, the risk of doing nothing is also high,”
said Dr. Vitello, Associate Professor of Surgery, University of
Illinois, Chicago.
Dr. Vitello noted that future developments such as the laparoscopically
placed gastric pacemaker may reduce the need for surgical procedures.
In 1991 the U.S. National Institutes of Health held a consensus
conference to develop guidelines for a surgical approach to weight
loss. The optimal candidate was profiled as being well informed
and motivated, with realistic expectations of outcomes. Ideally
such a patient would undergo a thorough evaluation by a team of
dietitians, psychiatrists/psychologists, internists and surgeons,
and agree to long-term follow up. The patient would also meet the
following clinical criteria:
• a BMI of at least 40 or of 35 to 39 with significant medical
comorbidities;
• a history of failed medically and nonmedically supervised
weight-loss programs;
• age 20 to 60 years;
• an acceptable surgical risk status;
• no substance abuse, psychoses or uncontrolled depression;
and
• no endogenous cause of obesity.
Medical complications
of obesity range from hypertension, type 2 diabetes and premature
vascular disease, to infertility, joint disease, increased cancer
risk and earlier mortality (Calle et al, NEJM 1999;341:1097-1105).
“In addition, there is a host of social, economic and psychiatric
issues which these patients have the potential to improve with long-term
weight loss,” Dr. Vitello said. “While insurance companies
don’t care about these issues, they are germane to patients
and fall under the umbrella of quality of life.”
Most patients, Dr. Vitello added, are very enthusiastic about bariatric
surgery. “All have struggled with their weight virtually their
entire life. Almost all have yo-yoed. Therefore, they look to surgery
as a viable solution with a high likelihood that it will work.”
Surgery for weight loss falls into three categories: restrictive,
malabsorptive, and combination.
Restrictive procedure
In 1983 in Norway, Bo and Modalsli introduced gastric banding using
a silicone band placed near the GE junction to create a small upper
segment and a narrow passage into the remaining stomach. “This
had the advantage of being simple to perform and reversible, avoiding
the inherent risks of stapling,” Dr. Vitello said.
Nowadays an adjustable silicone band can be placed laparoscopically
and connected to a subcutaneous port through which saline can be
injected or withdrawn. If weight loss is meagre, saline is added
to restrict the gastric opening. If vomiting is excessive, saline
is withdrawn. The new adjustable band is FDA approved. Complications
of this procedure include band migration, leakage, and reflux esophagitis.
Lap band has a controversial success rate. In Europe and Scandinavia
success is quoted as 60 to 80 per cent, but no long-term U.S. data
are available.
Vertical banded gastroplasty (VBG) was devised in 1982 by Mason
(Arch Surg, 1982; 117:701). VBG involves placing a vertical
staple line along the lesser curvature of the stomach to create
a small pouch (13 to 14 mL at 70cm of water pressure). The outlet
of the stomach was then banded with polypropylene mesh using a 5-cm
band. Complications include band erosion, stomal stenosis, food
bezoar, obstruction, vomiting, weight regain, pouch dilatation,
leakage, and staple line dehiscence. VBG has a 40 to 50 per cent
success rate and is falling out of favour.
Malabsorptive procedure
In 1954 Kremen and colleagues, working with dogs, laid the foundation
for a massive clinical experiment in the surgical control of obesity.
Jejuno-ileal bypass, pioneered by Payne and De Wind and modified
by Scott, was widely used in the 1960s and 70s.
In this procedure 14 inches of proximal jejunum was anastomosed
to fourinches of distal ileum in an end-to-side or end-to-end manner.
Though effective, the operation caused severe, even life-threatening
complications in one-third of patients: predominantly liver failure,
hepatosteatosis and cirrhosis. “Many more patients had to be
hospitalized for dehydration and electrolyte imbalances,” Dr.
Vitello said. Among other sequelae affecting many bypass patients
were cholelithiasis, urolithiasis (oxalate), anemia, vitamin deficiencies,
and migratory arthritis. “Almost no one I know performs the
intestinal bypass.”
Combination procedures
The current version of the proximal Roux-Y gastrojejunostomy creates
a small proximal gastric pouch holding just one to three ounces.
Distension of this small pouch creates pain and early satiety. A
Roux limb of varying length is sewn to this pouch, with the opening
between pouch and limb made small to prevent food from passing through
easily.
The remaining 97 per cent of the stomach is bypassed or excluded
but not removed. “Dumping occurs with the ingestion of refined
sugars, and 30 per cent of patients develop lactose intolerance
due to the bypassing of the duodenum,” Dr. Vitello said. Complications
include leaks, marginal ulcer, and deficiencies of vitamin B12 ,
folic acid and iron.
The distal Roux-Y gastric bypass essentially combines the restriction
of a small gastric pouch with an intestinal bypass for malabsorption.
In this procedure the Roux limb and the biliopancreatic limb meet
about 75cm from the common channel. Though resulting in more weight
loss than the proximal gastric bypass, this procedure is associated
with a higher incidence of disabling diarrhea and flatulence due
to steatorrhea from fat malabsorption. Abdominal cramps and protein/vitamin
malnutrition are also more common.
Developed in 1979 by Scoparino and colleagues, the biliopancreatic
diversion combined gastric resection with an intestinal malabsorption
procedure (Int J Obes 1981;5:421). The gall bladder is removed,
75 per cent of the stomach is resected and a 200cc to 500cc pouch
left (size depends on degree of obesity). The duodenal stump is
stapled closed and the ileum divided 250cm proximal to the ileocecal
valve. The distal segment is anastomosed to the remaining stomach.
Then the proximal jejuno-ileal segment (biliopancreatic limb) is
anastomosed to the side of the terminal ileum 50cm from the ileocecal
valve. This becomes the common ileal segment for digestion and absorption
of food. Biliopancreatic diversion (with or without duodenal switch)
has a success rate of 80 to 90 per cent.
Complications include: steatorrhea, fat malabsorption, vitamin deficiency,
abdominal cramps, excessive weight loss, iron-deficiency anemia,
protein malnutrition, stomal ulcer, and small bowel obstruction.
To avoid bypassing the pylorus, Hess and Hess developed the biliopancreatic
diversion with duodenal switch, a wedge resection of the greater
curvature of the stomach combined with a duodenal switch (Obes
Surg 1998;8:267-282). This operation divides the duodenum in
the distal bulb and divides the ileum 250cm proximal to the ileocecal
valve, with anastomosis of the proximal duodenal segment to the
distal ileal segment. The distal end of the transected duodenum
is oversewn as a duodenal stump.
The proximal ileal segment carrying the biliary and pancreatic secretions
is anastomosed end-to-side for an enteroenterostomy 50cm to 100cm
proximal to the ileocecal valve. Because of the intact pylorus,
this procedure avoids the dumping syndrome and has a lower incidence
of marginal ulceration than gastric bypass. And since the duodenum
is also intact, there is more normal absorption of calcium, iron
and vitamin B12. Patients report a better quality of eating than
with conventional biliopancreatic diversion.
At Dr. Vitello’s facility the procedure of choice is the Roux-Y
gastric bypass with a long (225cm) Roux limb. “The success
rate is between 60 and 80 per cent for long-term weight loss, meaning
that 60 to 80 per cent of patients lose 60 to 80 per cent of their
excess weight and maintain that for five years,” he said. “Type
II diabetes is eliminated in 80 per cent, hypertension is eliminated
in 50 per cent, and sleep apnea, GERD, and pseudotumour cerebri
are all cured.”
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