BLOCK AT A GLANCE
Injection of local anesthetic into the thoracic paravertebral space.
Indications: Analgesia after thoracic and breast surgery, rib fractures, and procedures involving the thoracic and upper abdominal wall
Goal: Spread of local anesthetic into the paravertebral space around the spinal nerves as they arise from the intervertebral foramen
Local anesthetic volume: 4 to 5 mL per space to be blocked
Thoracic paravertebral block (PVB) is a well-established analgesia interventional technique for patients having thoracic, chest wall, or breast surgery. Likewise, it is often used for pain management of patients with rib fractures. The PVB provides an effective unilateral block of the anterior and posterior branches of the corresponding spinal nerves, as well as the sympathetic chain. PVBs also may decrease the risk of chronic pain after breast and thoracic surgeries and reduce the recurrence of breast cancer, but this last possible benefit requires further confirmation.
Ultrasound (US) guidance helps to identify the paravertebral space (PVS) with more precision than the landmark-based technique. It also helps monitor the needle placement and the spread of the local anesthetic (LA). However, the use of US in the PVB requires a high degree of skill due to the close proximity of highly vulnerable structures and the depth of the PVS. The potential for complications and the challenges of the technique inspired the development of several alternative approaches targeting the branches of the spinal nerves at more distal and superficial locations. In this chapter, we describe general principles of thoracic PVB; readers are advised to use the anatomical and technique information presented here to devise their own approach in line with their experience.
Specific Risks and Limitations
The proximity of the needle tip to the pleura, neuraxial structures, and segmental arteries and veins carries the risk of pneumothorax, spinal cord injury, inadvertent spinal or epidural block, and vascular puncture. In patients on antithrombotic or thrombolytic therapy, the same precautions should be taken as for neuraxial techniques. One of the limitations of the PVB is the inconsistency of the craniocaudal spread of LA, which may require injections at multiple levels to cover the desired area.
The PVS is a wedge-shaped area between the heads and necks of the ribs that contain the thoracic spinal nerves and the sympathetic trunk (Figure 36-1). Its posterior wall is formed by the superior costotransverse ligament, the anterolateral wall by the parietal pleura with the endothoracic fascia. The medial wall is made by the lateral surface of the vertebral body and intervertebral disc. The PVS medially communicates with the epidural space via the intervertebral foramen inferiorly and superiorly across the head and neck of the ribs. Consequently, injection of LA into the PVS often results in unilateral (sometimes bilateral) epidural anesthesia. The cephalad limit of the thoracic PVS is not well defined, whereas ...