Page 115 - Clinical Manual of Small Animal Endosurgery

Diagnostic Laparoscopy 103

• the presence of a single- or double-action mechanism at the effector
end: in a single-action device only one jaw of the instrument is
moving, whereas in a double-action instrument both jaws move when
the operator’s hand moves; this mimics more closely the movement
of an open-surgery instrument, and is preferred when performing fine
dissection;
• electrosurgical capability (mono- or bipolar, etc.).

Finally, advantages and disadvantages of disposable and reusable instru-
ments have to be considered: disposable instruments are usually suitable
for multiple uses as long as sterility and sharpness are preserved. Reus-
able instruments, although more expensive, are easier to clean, lubricate
and sterilise. On the other hand, even reusable cutting instruments (e.g.
scissors) need to be sharpened, more often if their electrosurgical capabil-
ity is exploited.
Hand instruments are used for the following functions.

• Retraction: the simplest retractor is a blunt probe, which is used to
move and ‘palpate’ organs; the probe is also used to apply pressure
over a biopsy site to achieve haemostasis. The probe has 1 cm calibra-
tion markings along its shaft, for measurement of organs or lesions,
which otherwise could prove difficult in the presence of magnifica-
tion. Other types of retractor have projections that extend in a fan
shape, thus providing a wide retracting surface.
• Tissue handling: as in open surgery, grasping forceps can be traumatic
or atraumatic. Traumatic grasping forceps, such as laparoscopic Allis
forceps, have teeth and are used to grasp only tissue to be removed.
Atraumatic ones (e.g. laparoscopic Babcock and Debakey forceps)
have fine serrations that hold tissue firmly but delicately. However,
because of the loss of tactile feedback occurring in laparoscopy, even
atraumatic forceps can damage tissues if too much force is applied.
Avoiding the use of instrument ratchets helps the beginner in appre-
ciating tissue friability. Grasping instruments are available in various
shapes (blunt, curved, angled, duck-bill, dolphin-nosed), and may
also be used with electrosurgery.
• Dissection: dissecting forceps (Maryland dissectors, Kelly and right-
angle forceps, etc.) are used for blunt dissection. Curved and ‘cherry’
dissectors are useful for isolating blood vessels and delicate structures
such as the cystic duct. Sharp dissection is usually carried out with
scissors. Curved Metzenbaum scissors with 5 and 10 mm shafts are
most commonly used; for very fine dissection straight scissors and
micro scissors are available. Scissors can also be connected to elec-
trosurgery, or other energy devices such as lasers and electronic
scalpels can be used to accomplish dissection.