Page 142 - Clinical Manual of Small Animal Endosurgery

130 Clinical Manual of Small Animal Endosurgery

and also major abdominal vessel may be reached, especially in small
patients. Although the organ more commonly injured during needle or
trocar insertion is the spleen, because of its size and position, perforation
of hollow viscera such as stomach, intestine and bladder has also been
reported.
Various preventative measures are recommended to avoid these iatro-
genic complications. Transillumination of the body wall before insertion
of accessory portals allows identification of abdominal wall vessels; simi-
larly, placement of secondary portals under visual inspection decreases
the risk of damage to underlying organs. A controlled trocar insertion
is also important, and the non-dominant hand may be placed onto the
abdominal wall to act as a stop. Alternatively, the middle finger of
the hand manoeuvring the trocar can be extended along the trocar shaft,
to limit the depth of insertion. Other safety measures include emptying
the bladder (and the stomach in case of overdistension) before the pro-
cedure, ensuring an adequate degree of pneumoperitoneum and placing
the patient in a slight Trendelenburg position. The latter two steps are
directed at increasing the distance between organs and insertion site.
Finally, the Veress needle and the first trocar, which are inserted blindly,
must be aimed away from the spleen.
Abdominal insufflation with the Hasson (open) technique has also
been shown to significantly diminish the frequency of complications
(Twedt and Monnet, 2005); alternatively, the use of optical trocars
allows the passage of the endoscope into the lumen of the cannula during
insertion, so that the trocar’s progress can be monitored visually.
Early detection of complications is also essential to minimise damage:
the areas of Veress needle insertion is explored as soon as the primary
port is established, and the whole abdomen is inspected again before
closure. Perforation of a hollow viscus is usually readily apparent, as
urine or gastrointestinal contents are aspirated; Veress needle injuries are
often self-limiting, whereas trocar-induced damage needs to be repaired.
In this case, as in cases of significant haemorrhage due to spleen injury,
conversion to open surgery is usually necessary. Damage to viscera may
also occur during organ manipulation and biopsy, due to unexpected
findings (biopsy of vascular tumours, abscesses, hydronephrosis), coagu-
lopathies or inappropriate biopsy technique.
Complications secondary to insufflation are related to penetration of
air in areas other than the abdominal cavity: subcutaneous emphysema,
peritoneal tenting (air insertion between the muscle layer and the peri-
toneum), insufflation of the omentum, pneumothorax and gas embolism.
Subcutaneous emphysema and peritoneal tenting are considered minor
complications, but can create problems for continuing the procedure.
The emphysematous space may in fact be so deep that the tip of the
needle or trocar cannot easily reach the peritoneum. If this occurs, pneu-
moperitoneum must be established with the open technique; alterna-
tively, the procedure is abandoned and can be repeated as soon as
emphysema resolves, usually less than 48 h when carbon dioxide is the