|
The
complications of obesity surgery
By Kristin Jenkins
Baltimore,
MD—
Pulmonary embolus is probably the most common cause of unexpected
death in patients who undergo obesity surgery. With an incidence
of 0.2 to 3 per cent, it is fatal in a significant proportion.
“PE has been implicated in the sudden death of patients undergoing
this operation in the immediate postoperative period and up to a
month after the procedure,” Mark T. DeMeo, MD, said at the
annual meeting of the American College of Gastroenterology. The
overall incidence of deep vein thrombosis/pulmonary embolus in this
group is two per cent.
Atelectasis and/or respiratory complications have also been linked
to surgery in obesity. Leaks at the site of anastomosis or along
the staple line occur in approximately one to two per cent of open
procedures and in three per cent of laparoscopic procedures. The
most common late complication after open gastric bypass, however,
is incisional hernia which occurs in 10 to 20 per cent.
Rapid weight loss is the culprit in many complications associated
with obesity surgery, the most notable of which is the formation
of gallstones. “Some 95 per cent of stones occurred in the
first six months after surgery,” said Dr. DeMeo, Associate
Professor of Medicine, Rush University Medical Center, Chicago,
IL. The formation of gallstones or biliary sludge may be as high
as 50 per cent within the first six months post-op. This problem
appears to be related to the rapidity of weight loss and can be
significantly reduced by the use of ursodiol therapy at a dose of
300 mg bid.
Complications specific to restrictive procedures include internal
hernia and acute gastric distention, an uncommon complication that
can manifest in the bypassed segment as a result of edema or obstruction
at the enterostomy. The rate of stomal ulceration following undivided
gastric bypass is 12 to 15 per cent although the incidence of ulceration
is lower with a divided procedure, he said. “Ulcers usually
develop on the jejunal side of the anastomosis and etiology is likely
multifactorial and due to acid peptic disease, ischemia/tension
at the anastomosis and possibly as a result of the use of non-steroidals.”
Late gastrointestinal hemorrhage (more than 10 years after surgery)
is rare but can originate in the excluded stomach-duodenum. If the
bleeding site is not localized, resection of the surgical remnant
is recommended
Stomal stenosis, a relatively common complication, is estimated
to occur in five to 12 per cent of restrictive procedures, said
Dr. DeMeo.
“The majority of patients respond to endoscopic dilatation
but some require operative revision. Staple-line disruption can
occur in the setting of a vertical banded gastroplasty as well as
after an undivided gastric bypass procedure and symptoms may be
subclinical, hindering intervention. Major wound infection after
gastric surgery is reported in the one-to-three per cent range,
said Dr. DeMeo.
Nutritional complications can occur following obesity surgery. Protein-calorie
malnutrition is relatively uncommon in standard restrictive procedures,
he said. However, iron-deficiency anemia can occur, as can B12 and
folate deficiency, and calcium malabsorption. Metabolic bone disease
and bowel obstruction are also seen in these patients.
The length of the common channel may be a key factor in determining
the presence and severity of nutritional complications. These can
include: severe protein-calorie malnutrition, fat malabsorption
resulting from fat soluble vitamin deficiencies, and compromised
B12 levels resulting from a disruption of the enterohepatic circulation.
If the patient is asked to bring in a food diary, it will often
show that, with the exception of Vitamin C, intake of protein, iron
and zinc is well below RDI levels. “Most patients are provided
with supplements but we have found that compliance is generally
poor,” he said.
In malabsorptive operations, osteoporosis and renal oxalate stones
may result from calcium malabsorption. “However, bone metabolism
can also be affected after gastric bypass operations. Studies suggest
that there can be a four per cent change in bone mineral density
following this operation.” While this change may be subtle
over a one-year period post-op, “the loss of bone mineral density
can have serious long-term implications,” he said.
In malabsorptive procedures, bacterial overgrowth in the bypassed
segment can lead to bypass enteritis, iron-deficiency anemia, interstitial
nephritis, pneumotosis intestinalis, GI tract bleeding and antigen-antibody
joint deposition resulting in rheumatologic complaints. Bacterial
overgrowth in the bypassed segment has been implicated in hepatic
dysfunction and/or cirrhosis, possibly due to portal endo-toxemia.
Overall, laparoscopic banding has been associated with a disappointing
weight loss and a higher degree of complications such as pouch dilatation,
stomach slippage, band erosion and leakage, tube leakage, and infection.
Up to 23 per cent of patients will require additional surgery, Dr.
DeMeo said.
When a post-op bariatric surgery patient develops symptoms or fails
to lose weight, endoscopy can be used to evaluate and manage complications.
Endoscopic balloon dilatation can be used in suspected stomal stenosis;
endoscopic access can be used to evaluate and manage bleeding or
jaundice; and gastrocutaneous
fistula can be managed with endoscopic fibrin sealing.
|
