Thoracoscopy

• Minimal invasive procedures such as thoracoscopy are gaining popularity within the veterinary field as they have the potential to decrease morbidity, improve magnification, reduce pain and days in hospital.
• This is a large subject and a short introduction will be given here. Further reading suggestions have been added at the end.

• Include the following: 
• Diagnosis of:
  • Thoracic foreign body Thorax: masses.
  • Thoracic neoplasia.
  • Thoracic abscess.
  • Biopsies.
  • Lymphadenectomy.
• Treatment options include:
  • Pericardectomy.
  • Lung lobectomy Lung: lobectomy.
  • Abscesses.
  • Mediastinal and right auricular mass resection Thorax: median sternotomy.
  • Thermal ablation.
  • Chylothorax Chylothorax.
  • Spontaneous pneumothorax - bullae, blebs Pneumothorax.

Advantages

• Reduced pain and post-operative discomfort.
• Reduced hospital stay.
• Operative magnification.
• Sentinel lymph node mapping and thoracic duct visualization using near-infrared technology. 

Disadvantages

• Cost of equipment.
• Learning curve and training.
• Visualization decreased in cases with adhesions and sometimes in barrel chested patients. 
• Cardiopulmonary changes.

• Thoracotomy, median or intercostal Thorax: thoracotomy (intercostal).

Preparation

• 30 min.

Procedure

• 30 min or longer depending on the intervention required.

Veterinarian expertise

• Specialist surgeon - referral level.

Anesthetist expertise

• Specialist anesthetist - referral level.

Nursing expertise

• Advanced.

Other involvement

• Intensive care unit.

Minimum equipment

• Light source.
• Light guide cable.
• Camera unit.
• Camera head.
• Monitor.
• Archiving system.
• Endoscope:
  • Rigid 5 mm 0˚ and 30˚ or
  • Rigid 3 mm 0˚ and 30˚.
• Thoracoports 5 mm or 3 mm.
• Threaded cannula, eg EndoTip.
• Ventilator.
• Diathermy.
• Palpation probe.
• Suction-irrigation device.
• Vessel sealing devices, eg ENSEAL, Ligasure, Harmonic ACE.
• Soft tissue kit for open thoracic surgery and Finochiettos in case of conversion.
• Chest drain, eg Mila chest drain 14 French.  
   
• If therapeutic or diagnostic intervention is required the following include some of the equipment required but is not an exhausted list for all procedures;
  • Stapling devices, eg EndoGIA tapler, PROXIMATE TX30 stapler, laparoscopic clips M/L-10.
  • Pre-tied ligature loops, eg Endoloop.
  • Fan retractor.
  • Endoscopic; Babcock forceps, grasping forceps, scissors, needle drivers.
  • Laparoscopic right-angle forceps.
  • Retrieval bag.
  • J-hook.

Ideal equipment

• Endoscope: ENDOCAMELEON – allow a wide range of scope angles in one scope ranging between 15˚ - 90˚.
• Ceiling booms with minimum two adjustable monitors.
• One-lung ventilation equipment.
• Near-infrared imaging system such as the D-light from Karl Storz.

Minimum consumables

• Drapes.
• Swabs.
• Suture to close the portal incisions.

• Clip both sides of the thorax and the cranial third of the ventral abdomen.
• Aseptic skin preperation Surgery: asepsis.

• General anesthesia General anesthesia: overview.

Example given here is a brief description of the approach for pericardiectomy

Step 1 - Positioning

• Dorsal recumbency, one-lung ventilation is not required.

Step 2 - Paraxiphoid portal placement

• 1 cm incision, 1 cm the right caudolateral side of the xiphoid process.
• Place the threaded EndoTip cannula is placed through the skin incision in a cranial 45˚ angle through the diaphragm. Some force is needed while screwing the tip though the diaphragm.
• Once a pneumothorax and partial lung collapse has been introduced the chosen telescope is introduced to visualize the thoracic cavity. A small window through the mediastinum can be made with the tip of the scope to visualise the other side as well.

Step 3 - Instrument portal placement

• Under direct telescope visualization a thoracoport is placed in the sixth intercostal space on both the left and the right side.
• A fourth portal is placed in the left third or fourth intercostal space, in case suction and irrigation is required.

Step 1 - Pericardiectomy

• Pericardial window, with or without vertical pericardial fillets or subphrenic pericardectomy is then performed.
• The pericardium is grasped and lifted with a stay suture or endoscopic graspers.
• This procedure is performed with a vessel-sealing device. Care should be taken not to transect the phrenic nerve or damage the auricles.

• The resected pericardium is sent for histopathology.

Step 2 - Chest drain

• Insertion using the Seldinger/catheter-over-guidewire technique Seldinger (over the wire) technique under direct scope visualization will reduce the risk of iatrogenic trauma to the lung parenchyma. This also rules out the need for postoperative radiographs to confirm the positioning of the drain Drainage: thorax.

Step 1 - Close

• Remove the instruments.
• Close the facial planes with 3-0 or 2-0 polydioxanone (PDS), subcutaneous and intradermal layers with 4-0 or 3-0 polyglecaprone 25 (Monocryl).

Step 2 - Re-expand lungs ​

• Use a three-way-tap and a 10 ml syringe to slowly re-expand the lung lobes by emptying the pneumothorax slowly or in increments to reduce the risk of re-expansion injury to the lungs.

Monitoring

• Monitor fluid and air output from the chest drain. Remove at clinician’s discretion.
• Initial recovery in the intensive care unit.

Wound Protection

• Primapore for 12-24 hours.

Potential complications

• Iatrogenic trauma to lung parenchyma, phrenic nerves and auricles.
• Iatrogenic trauma to vessels, eg intercostal neurovascular bundle.
• Thermal injury to pulmonary and cardiac structures during procedures.
• Re-expansion injury to the lung tissue.

• Postoperative portal infections, seromas Seroma or port site metastasis.

Refereed papers

• Recent references from PubMed and VetMedResource.
• Balsa I M & Culp W T N (2019) Use of Minimally Invasive Surgery in the Diagnosis and Treatment of Cancer in Dogs and Cats. Vet Sci 6 (1), E33 PubMed.
• Cronin A, Pustelnik S B, Owen L et al (2019) Evaluation of a pre‐tied ligature loop for canine total lung lobectomy. Vet Surg 48 (4), 570-577 PubMed.
• Steffey M A & Mayhew P D (2018) Use of direct near-infrared fluorescent lymphography for thoracic duct identification in 15 dogs with chylothorax. Vet Surg 47 (2), 267-276 PubMed.
• Brisson B A, Reggeti F & Bienzle D (2006) Portal site metastasis of invasive mesothelioma after diagnostic thoracosopy in a dog. JAVMA 229 (6), 980-983 PubMed.

Other sources of information

• Fransson B & Mayhew P (2005) Small animal laparoscopy and thoracoscopy. 1st edn. ACVS Foundation: Wiley Blackwell.

• Veterinary Endoscopy Society: www.veterinaryendoscopysociety.org/home.