Page 189 - Clinical Manual of Small Animal Endosurgery

Thoracoscopy 177

Fig. 6.5 Although flexible lung retractors can be useful in dorsal
recumbency thoracoscopy, there is often insufficient space for their use in
lateral recumbency, where a simple palpation probe is better suited to
retraction of lung in the limited operating space.

of the pleural space, have also been used to increase the operating space
available during thoracoscopy, but carry disadvantages (see below).

Electrosurgery and related modalities

Monopolar surgery
Monopolar electrosurgery holds the advantage over bipolar electrosur-
gery of allowing cautery as well as cutting dissection, but has limited
application in thoracoscopic surgery as its use in proximity to the heart
is best avoided. It carries a higher risk of causing inadvertent injury than
bipolar surgery, or an ultrasonic scalpel. Care is especially needed in
small veterinary patients with thick coats, which can prevent good
contact with the return electrode (ground plate) and result in burn inju-
ries. The safety of monopolar surgery can be increased by using higher-
frequency current, referred to as radiosurgery (Surgitron, Ellman), in the
order of 3.8–4.0 MHz, which has less reliance on good contact with the
return electrode. The cutting and dissecting function of monopolar elec-
trosurgery is increasingly being replaced in human surgery by ultrasonic
scalpels (see below), which coagulate and cut tissues via ultrasound, with
little collateral heat generation, and no risk of contact plate burns.

Bipolar electrosurgery
Bipolar electrosurgery is more suitable to thoracoscopic surgery than
monopolar surgery and provides precise controlled electrocautery with