Six normal, healthy horses age 3-10 years underwent left and right thoracos
copic examination using a rigid telescope. A minimum of 30 days was allowed
between procedures. Horses were restrained in stocks and sedated with a co
ntinuous detomidine infusion. After surgical preparation of the hemithorax
elected for surgery, and administration of local or regional anaesthesia of
the surgery sites, thoracoscopy was completed during two 15 min pneumothor
ax periods. During the procedures, the thoracic structures were viewed usin
g a 57 cm, 10 mm diameter, 30 degrees rigid telescope connected to a digita
l camcorder to allow computer capture of digital images. The telescope was
inserted into the thoracic cavity via 3 different intercostal spaces. The 8
th, 10th and 12th intercostal spaces were randomly selected and used among
horses. The exploration of each hemithorax started from the dorsal-caudal q
uadrant continued toward the cranial thorax and was completed by observing
the diaphragmatic and caudal pulmonary region.
Collapsed lung, aorta, oesophagus and diaphragm were viewed readily in eith
er hemithorax. On exploration of the right hemithorax, the azygos vein, tho
racic duct and pulmonary veins were also identified. Horses tolerated thora
coscopy well. Signs of discomfort, such as increased respiratory rate, coug
hing and decreased level of sedation, were associated with lung collapse in
one horse, with pneumothorax on 2 occasions, and when the thorax was appro
ached through the 8th intercostal space. Surgery performed via the 8th inte
rcostal space was hindered by the rigidity of the 8th and 9th ribs, and by
the presence of a greater musculature, which did not allow easy cranial and
caudal movements of the telescope.