Thoracic surgery (part I) (Proceedings)
The choice of surgical approach depends largely on the type of access needed for the thoracic surgery. Intercostal thoracotomy and median sternotomy are the two most commonly performed approaches in small animals. Be certain to clip and prepare a large enough area to anticipate placement of a thoracostomy tube and the potential need to extend the incision.
Intercostal thoracotomyUse this approach to expose a specific region of a hemithorax. Intercostal thoracotomy provides good access to the hilar area of the lungs and the heart. Additionally, exposure of the mediastinum and a portion of the ipsilateral thoracic cavity is achieved. Spaces available for performing an intercostal thoracotomy are the third through the tenth, although the fourth through the sixth intercostal spaces are more frequently entered.
Use the lateral thoracic radiograph to help determine the appropriate intercostal space to incise. Remember that when performing a lung lobectomy, center the approach over the hilus of the lung not over the lesion (cranial lobe - 4th or 5th, middle lobe - 5th, caudal lobe - 6th intercostal space). Use a 4th intercostal thoracotomy incision (5th in the cat) to expose the heart in the dog. Use the 8th intercostal space to expose the caudal esophagus.
Incise the skin parallel to the ribs and have the incision extend from just ventral to the costovertebral junction to just dorsal to the sternum. Incise the latissimus dorsi muscle with scissors parallel to the skin incision. Verify intercostal space identification by counting caudally from the first rib. Incise the serratus ventralis muscle parallel to its fibers to expose the desired intercostal space. Incise the intercostal muscles midway between ribs to avoid the intercostal vessels and nerve. Bluntly puncture the pleura to allow the lungs to fall away from the lateral thoracic wall before extending the intercostal incision with Mayo scissors. The intercostal muscle incision should extend ventral to the costochondral junction to assure adequate exposure. Insert rib retractorsa over laparotomy sponges to protect skin and muscle.
Place a thoracostomy tube as described below. Close the intercostal space by placing heavy (usually 0 or #1 suture) absorbable sutures (polydioxanone or polyglyconate) circumcostally to appose the ribs. Pre-place these sutures to help avoid traumatizing adjacent structures. Close the serratus ventralis and scalenus muscles as a separate layer. Close the latissimus dorsi muscle separately with a simple continuous pattern of absorbable material incorporating the fascia as much as possible. Close the subcutaneous tissue and cutaneous trunci muscle together. Close the skin in routine fashion.