Page 195 - Clinical Manual of Small Animal Endosurgery

Thoracoscopy 183

and lung movements this is even more important than in laparoscopy in
preventing inadvertent entry injuries.
The most suitable ports for intercostal primary (optical) port place-
ment are soft, flexible ports with a blunt atraumatic trocar (see above).
After a skin incision over the selected intercostal site, the port can be
bluntly pushed through the intercostal muscles. Alternatively the chest
may be entered with blunt dissection with curved artery forceps to initi-
ate a pneumothorax before insertion of the port. The primary ports
should not be inserted at or ventral to the costochondral junction. The
endoscope is then inserted, and the underlying lung and other structures
examined for any injury. The locations of the other ports can then be
selected based on the individual’s specific anatomy and the procedure to
be performed. These ports can be safely placed under endoscopic visu-
alisation. Sharp trocars should not be used for primary access due to the
high risk of lung trauma, even if a prior pneumothorax is established.
The Veress needle was originally used for inducing a pneumothorax
prior to surgical treatments of tuberculosis and pleural adhesions in
humans, before it was later adopted for insufflation prior to laparoscopy.
While this double-lumen, guarded needle could still be used before
primary port placement, it holds no benefit over simply using a blunt
trocar, and can still traumatise underlying lung.
Some favour the use of a paraxiphoid transdiaphragmatic placement
of the primary optical port for procedures in dorsal recumbency, such
as subtotal pericardiectomy. A threaded cannula is recommended. A 0°
endoscope is used for intraluminal visualisation during placement. Insertion
of the cannula is directed dorsally, and towards the opposite shoulder.
In chronic disease cases with notably thickened pleura insertion can be dif-
ficult if not directed adequately dorsally during placement (Radlinsky, 2008).

Exploratory thoracoscopy

Exploratory or diagnostic thoracoscopy is an extremely useful technique,
and notably less invasive than an exploratory thoracotomy. Even with
advanced diagnostic imaging such as computed tomography scanning,
which may localise a specific lesion, sampling is needed for a definitive
aetiological diagnosis, such as in the case pictured in Fig. 6.8. In many
cases it is not possible to achieve this safely blindly, or under ultrasound
guidance. In human surgery, thoracoscopy and excisional biopsy are
usually the diagnostic modalities of choice for single isolated pulmonary
nodules less than 2 cm in diameter.
The diagnostic yield at histology and microbiological culture of tho-
racoscopic lung biopsies has been demonstrated to be comparable to
open surgical biopsy (Faunt et al., 1998). Thoracoscopy also allows the
opportunity to proactively address any haemorrhage or air leakage that
may occur at the time of biopsy, rather than as a later unexpected emer-
gency after performing ultrasound-guided needle or Trucut biopsy.