Chapter 11b - Regional Anesthesia: Chest and Abdominal Plane Blocks

Summary

The intercostal nerves are the continuations of the ventral ramus of the thoracic spinal nerves. To perform an effective ICB, the block should be performed proximal to the mid-axillary line, where the lateral cutaneous branch takes off. ICBs can be performed using landmarks, a nerve stimulator, or under ultrasound guidance. Evidence supports the effectiveness of ICBs for chest tube placement, rib fractures, and procedures of the breast and chest wall. Limitations of ICBs include the need to perform blocks at multiple levels (each level of fractured rib) and their association with a shorter duration of action, compared to other chest wall fascial plane blocks such as pectoralis (PECS) II block and serratus anterior plane block (SAP). This is mainly related to a high rate of absorption of local anesthetic within the intercostal space. These considerations make ICBs a less favorable option, as with each injection, there is a potential risk of complications, such as neurovascular injury and pneumothorax. The risk of local anesthetic systemic toxicity (LAST) may also be increased with multiple intercostal injections related to the highly vascularized bundle located underneath each rib, resulting in a high rate of absorption.