Page 129 - Clinical Manual of Small Animal Endosurgery

Diagnostic Laparoscopy 117

surgery if the indication arises, for example in case of resectable disease.
The shorter postoperative recovery time is beneficial in critically ill
animals, and in cancer cases chemotherapy can be started sooner than
with open procedures.

Hepatobiliary disease
One of the most common indications for laparoscopic examination and
biopsy is hepatobiliary disease. Although many liver diseases are non-
surgical, tissue samples are often required to obtain a diagnosis. Fine-
needle aspirates cannot define lobular liver architecture and even core
biopsy techniques often do not provide large enough samples to allow
evaluation of liver architecture.
Laparoscopic liver biopsy allows excellent evaluation of the organ, and
consequent precise sampling of the desired areas. Acquisition of larger
pieces of tissue and a greater number of samples than those obtained with
percutaneous needle biopsy increases the chance of a correct diagnosis.
Percutaneous biopsy is also associated with an increased risk of inadvert-
ent organ perforation. Visual confirmation of haemostasis – and the
possibility to deal with haemorrhage directly – are of further advantage.
Before obtaining a liver biopsy coagulation parameters should be
evaluated. Platelet count, prothrombin time (PT), partial prothrombo-
plastin time (PPT) and mucosal bleeding time should be included.
Although coagulopathies are a relative contraindication of laparoscopic
liver biopsy, evaluations in vitro do not accurately predict the occurrence
of bleeding after biopsy. Consequently, the administration of vitamin
K or blood products before laparoscopic liver biopsy in patients with
coagulation parameter abnormalities is usually not necessary.
When multiple organ examination and biopsy is required, the animal
is placed in dorsal recumbency and a subumbilical telescope port is used.
With the animal in a head-up position, the convex surface of the liver is
easily visualised, although in obese patients the midline structures can
be obscured by the falciform ligament. If the stomach is distended, an
orogastric tube needs to be placed to aspirate gastric fluid to improve
access to the liver. To provide access to the concave surface of the liver
the animal has to be in a Trendelenburg position (with the head down).
Tilting to the side instead increases visualisation to the contralateral liver
lobes. The first instrument port is placed under direct visualisation in a
paramedian position in either the right or left cranial quadrant of the
abdomen, taking care not to place the cannula cranial to the last rib.
This could in fact lead to entry in the thoracic cavity, with consequent
pneumothorax. The minimum number of instrument portals that will
provide access to all organs to be biopsied are created; the liver can be
accessed through the same instrument portals used for the other laparo-
scopic procedures planned. In most cases two or three instrument ports
are sufficient. A second port is usually placed on the contralateral side.
In cases where a focal lesion is present the instrument port should be
placed on the ipsilateral side.