Erector spinae plane (ESP) block is a newer fascial plane block. It provides analgesia primarily by local anaesthetic spreading to:

• A The epidural space by tracking along spinal nerve roots through intervertebral foramina
• B The paravertebral space exclusively via direct injection under direct ultrasound visualisation
• C The intercostal nerves by following the posterior intercostal membrane plane
• D The dorsal and ventral rami of thoracic spinal nerves by spreading deep to erector spinae muscle in the costotransverse space ✓

Explanation

The erector spinae plane (ESP) block is performed by injecting local anaesthetic between the erector spinae muscle group posteriorly and the transverse processes anteriorly. The injectate spreads cephalocaudally in this fascial plane and penetrates anteriorly through the costotransverse foramen into the costotransverse space, where it contacts the dorsal and ventral rami of thoracic spinal nerves as well as rami communicantes (sympathetic). The block provides both somatic and visceral analgesia, making it useful for thoracic, abdominal, and thoracoscopic surgery. Epidural spread is possible but is not the primary mechanism.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.