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ABDOMINAL ULTRASOUND
Table 11.1
biopsy
fluid collections is used to establish their
exact nature: this may include haematoma,
lymphocoele, urinoma, biloma, pseudocysts and
others.
Postoperative haematomas are normally treated
conservatively and tend to resolve spontaneously.
Insertion of a drain into such a collection is at high
risk of converting the collection into an abscess.
Abscess drainage
Complications of ultrasound-guided
Major
Number
compliof
Mortality cation
Author Year biopsies rate rate
Fornari et al 4 1989 10 800 1:5400 1:530
Nolsoe et al 6 1990 8000 1:2700 1:540
Smith 7 1991 16 400 1:3300 —
Ultrasound-guided drainage of abscesses is now
the preferred treatment when the collection can
be visualized on ultrasound and a safe route chosen.
These may result from postoperative infection,
inflammatory bowel conditions, such as
Crohn’s disease or appendicitis, or other sources
of infection, particularly in immunosuppressed
patients. Drains come in different sizes and generally
the thicker the pus, the larger the bore of
drain that is required. Whilst aspiration is initially
performed to confirm the nature of the collection,
very often a drain is left in situ; together
with appropriate antibiotic therapy this is usually
effective. At the very least it normally leads to an
improvement in the overall clinical condition to
allow definitive treatment and can in itself be a
definitive cure.
Ultrasound is particularly useful in cases of hepatic
abscesses and in draining the subphrenic, pericolic
and subhepatic areas. Superficial collections, usually
associated with wound sites, are also readily accessible
to ultrasound. Collections obscured by bowel gas
are best drained under CT guidance.
Gallbladder drainage
Gallbladder drainage under ultrasound control is a
temporary, palliative procedure which tends to be
reserved for particularly ill patients with septicaemia,
as a method of stabilizing their condition
prior to surgery. Drainage of, for example, a gallbladder
empyema buys useful time, reducing the
risk of perforation and subsequent peritonitis and
improving clinical status prior to surgical removal.
Although the portable nature of ultrasound allows
a bedside procedure to be performed (which is particularly
useful in patients under intensive therapy
who cannot be moved), these procedures carry a
high risk to the patient and full anaesthetic, nursing
and medical support is required.
Nephrostomy
Renal obstruction in which the pelvicalyceal system
is dilated may be alleviated by the percutaneous
introduction of a nephrostomy tube under ultrasound
guidance. This procedure relieves pressure in
the renal collecting system and avoids potential irreversible
damage to the renal parenchyma (Fig.
11.11). Although the procedure may be carried out
completely under ultrasound control, it is normally
performed in a screening room where a combination
of ultrasound and X-ray screening can be used
to maximal effect.
Cyst drainage
The percutaneous treatment of renal and hepatic
cysts by simple aspiration may afford only temporary
relief as they frequently recur, but a more permanent
result may be achieved by injecting a sclerosant, for
example absolute alcohol or tetracycline into the
cyst. In addition, percutaneous treatment of hydatid
liver disease (traditionally avoided because of the risk
of spreading parasites along the needle track and
causing further infection) has been successfully performed
by injecting of a scolicidal agent, 11 avoiding
the need for surgical removal.
Other applications include draining of pancreatic
pseudocysts and inserting a cystogastrostomy
tube with combined fluoroscopy and ultrasound
guidance; the cyst is allowed to drain through this