A lateral thoracotomy is a surgical procedure to enter the chest cavity of dogs. It is performed by making an incision on the side of the body between two ribs. Common indications for this surgical approach are to treat primary lung tumors, lung lobe torsions, congenital cardiac vascular anomalies (i.e. patent ductus arteriosus, vascular ring anomalies), and chylothorax.

Unfortunately, lateral thoracotomies are a surgical procedure that is associated with significant post-operative pain in dogs and humans. Currently, most canine patients receive both a non-steroidal anti-inflammatory, as well as an opioid (morphine-like) medication in the post-operative period to help manage this discomfort. However, opioid medications come with potential negative side effects including decreased respirations, nausea, vomiting, decreased appetite, and sedation. In addition, there is a shortage of these medications currently available to veterinarians given ongoing supply chain issues and the opioid crisis in the United States.

Local anesthetics are medications that are injected under the skin that numb a region of the body for a period of time. A common example of a local anesthetic that is used in humans is Novocain, which is used to numb a section of your mouth for a dental procedure, and it only lasts for a few hours. There are several of these medications available that last for varying lengths of time. In addition, repeated dosing of these medications can be performed through a catheter under the skin to the area of desired pain relief during recovery in the hospital. A long-acting, one-time injectable form of local anesthetic exists in both human and veterinary medicine that lasts for 72 hours. Local anesthetics have been used in human medicine to provide effective pain relief following major surgical procedures, such as LT.

The goal of this study is to compare the efficacy of two local anesthetic techniques at providing post-operative pain control in dogs following LT without the use of opioid pain medications. One group of patients will receive an injection of a local anesthetic that lasts for 72 hours at the time of surgery. The second group of patients will receive repeated doses of a shorter-acting local anesthetic through a catheter under the skin for 72 hours. All patients will undergo rigorous pain assessment at set points following surgery to assess the effectiveness of each treatment and to ensure that no patient experiences discomfort.

Lateral thoracotomy is the most commonly used surgical approach to the chest cavity in both humans and dogs, and currently, this procedure is associated with significant discomfort that is treated with opioid medications. Given the current opioid crisis in the United States and limited availability of these medications in veterinary medicine due to supply chain shortages, the results of this study could lead to a decrease in the use of opioid medications in human and canine patients following LT and to a change in the standard of care following LT. In addition, the results of this study could support a change in post-operative pain control following a variety of additional surgeries in both veterinary and human medicine.

Dog owners can benefit from a significantly reduced surgical and treatment cost.

• Patients diagnosed with a condition that could be addressed via a lateral thoracotomy
• Patients at least 5 months old that weigh greater than 2 kg (4.4 pounds)
• Patients that can receive a non-steroidal anti-inflammatory (NSAID)
• Patient must be able to stay in the hospital for at least 72 hours post-operatively