Current status of the erector spinae plane block

Erector spinae plane block (ESPB) was first reported as a technique, blocking the posterior ramus of the spinal nerves to obtain analgesia in the back. After the original report, many reports have suggested that ESPB could obtain a broader analgesic effect than initially thought and be effective in thoracic or abdominal surgery. By the ESPB, the local anesthetic spreads laterally and blocks the lateral cutaneous branch of the intercostal nerve. Another possibility is the local anesthetic infiltrates ventrally and migrates to the paravertebral space or epidural space. However, the results of the cadaver examination, whether the local anesthetics can reach the paravertebral space were inconsistent. Recently, the clinical effectiveness of ESPB has been reported in thoracic surgery and abdominal surgery. However, the clinical effect of ESPB might be only due to an increase in the blood concentration of local anesthetics. The ideal target might be a deeper site than that currently used in ESPB to reach the paravertebral space. Further studies will investigate more effective and reliable sites for pain relief by injecting local anesthetics around the erector spinae muscle.