Page 125 - Clinical Manual of Small Animal Endosurgery

Diagnostic Laparoscopy 113

are placed with a twisting motion after a small incision in the abdominal
wall, they are less easily dislodged during instrument insertion or removal.
Since the cold glass of the telescope lens tends to cause condensation of
peritoneal moisture, the telescope should be warmed before insertion to
prevent lens fogging. This is usually achieved by placing its tip into warm
(40°C) sterile saline for 1–2 min, or holding it in the palm of the hand for a
few moments. Anti-fogging solutions are also commercially available, or
a povidone-iodine solution can be wiped across the distal lens. However,
warming techniques are usually preferred, as the layer of solution can
sometimes cause image distortion. Directing the carbon dioxide flow
away from the endoscope also helps in avoiding the problem; in some
cases gas inflow may need to be moved to an operative port. If fogging
occurs during the procedure, gently touching the laparoscope tip on
a serosal surface is usually sufficient to clear the lens. However, sometimes
it is necessary to withdraw the telescope and clean it with a moist swab.
The light cable is then connected to the telescope, and its other end
is handed to an assistant to be attached to the light source. The video
camera is attached to the telescope, and the video system is turned on.
Before entering the abdomen, the camera is ‘white-balanced’ by pointing
it towards a white surface (this makes monitor colours more accurate)
and focused until the image is sharp. The telescope can now be advanced
trough the cannula and into the abdomen.
In order to facilitate precise localisation of lesions, and operative
procedures, the camera is positioned so that the image on the monitor has
the same orientation of the abdominal contents. To achieve this, the cable
attached to the camera head always has to be directed towards the table. Once
the telescope is in the abdomen, adequacy of pneumoperitoneum and pres-
ence of adhesions are verified, and the puncture sites (Veress needle and
trocar-cannula unit) are inspected for damage to underlying organs. Occa-
sionally the omentum can be draped over the scope on abdominal entry,
interfering with visualisation. In this event, the omentum can be removed
by positioning the scope slightly inside the cannula, and slowly withdrawing
the cannula itself from the abdomen, until the omentum detaches.
The sites of insertion of secondary ports can now be chosen, depending
on the procedure to be performed and on the anatomy of the patient.
The selected locations must provide optimal access to the organs inter-
ested by the procedure, and have to be distant enough from the laparo-
scope (and from the organs themselves) to allow instrument manoeuvring
without interference (Fig. 4.6 shows the triangulation technique). In situ-
ations where only one secondary portal is used it is usually placed on
the side of the telescope of the operator’s dominant hand (Fig. 4.7).
The telescope and operating instruments also have to point towards the
monitor, and the surgeon stands behind the camera, facing the monitor.
When using telescope and secondary portals of the same size, it is some-
times convenient to switch locations between them.
Insertion is accomplished under direct visualisation. The proposed
entry site is transilluminated with the telescope, thus identifying any
large vessel present, and the skin depressed with a finger. This allows