Imagine exploring the thoracic cavity and performing surgical interventions without using an intercostal or a median sternotomy.
This is possible when you perform thoracoscopy—a technique widely used in human thoracic and cardiac surgery. Minimally invasive
video-assisted endoscopy and minimally invasive surgical instrumentation allow practitioners to perform diagnostic and advanced
therapeutic procedures in the thoracic cavity.1 Thoracoscopy is indicated for exploration of the thoracic cavity, diagnosis of pleural effusion of unknown origin, and pericardial
effusion.2-4 Biopsy of the pleural surface, lymph nodes, pericardium, and lungs can be performed during thoracic cavity exploration. Veterinary
literature reports the use of thoracoscopy to perform lung lobectomies, ligate thoracic ducts, and correct persistent right
Eric Monnet, DVM, MD, PhD, DACVS, DECVS
What you will need
The basic thoracoscopy equipment includes a surgical telescope (Figure 1), trocar-cannulas, a basic set of thoracoscopic surgical instruments, a light source, a video camera, and a video monitor
(Table 1). Thoracoscopy doesn't require CO2 insufflation because the rib cage keeps the thoracic cavity expanded.
Telescopes used for thoracoscopy are most commonly 5 mm in diameter and 30 cm long. This scope size works in a wide range
of animals. Telescopes are available with different angles, and the forward-view 0-degree and the forward oblique 30-degree
telescopes are most commonly used. The 0-degree telescope allows a natural field of view and a normal perspective to organ
orientation. The 30- degree telescopes allow better visualization of areas in the thoracic cavity that are difficult to access.
However, orientation and manipulation are more difficult with the angled scopes.
Cannulas for thoracoscopy are either open or closed. Closed cannulas feature a valve that allows the veterinarian to create
a controlled pneumothorax. They can potentially induce a tension pneumothorax during the procedure. Open cannulas create an
open chest, as in a thoracotomy. Open cannulas are preferred for long surgical procedures because they reduce the risk for
tension pneumothorax. Cannulas come in different diameters. The recommended diameter is 12 mm because most stapling equipment
available for thoracoscopy is 10 mm in diameter.
Numerous instruments are available for endoscopic exploration and surgery. The basic instrument set consists of grasping forceps,
scissors, biopsy forceps, and a palpation probe. Forceps and scissors are insulated for electrocautery. Electrocautery can
be used to cauterize small blood vessels during resection of the mediastinum or pericardium. For lung biopsies, pretied ligatures
can be used, which eliminate the need for knot tying inside the thoracic cavity. Retractors are required to hold lungs away
from the camera and obtain a clearer surgical field. Ligating small blood vessels in the mediastinum requires vascular clip
applicators, which come in different sizes, and lung lobe resections necessitate the use of stapling equipment. The Endo GIA
stapling device (Tyco Healthcare/Kendall Animal Health) comes in three lengths: 30, 45, and 60 mm. Staples come in lengths
of 2.0, 2.5, 3.5, or 4.8 mm. Finally, suction and irrigation devices are available to aspirate blood during the procedure
and lavage the surgical field and thoracic cavity.
Figure1. A 5-mm forward view telescope. The telescope is 30 cm long.
As for equipment, two types are recommended for advanced surgical procedures using minimally invasive surgery: radiofrequency
and ultrasound-based equipment. They provide fast, safe sealing of blood vessels without using suture materials. Radiofrequency
equipment can safely seal an artery with a diameter of less than 7 mm. Ultrasound-based equipment allows the practitioner
to cut through the tissue and seal the blood vessels. Vessels sealed using ultrasound technology should have a diameter of
less than 3 mm.