Randomized trial comparing the spread of retrolaminar block with the combination of erector spinae block and retrolaminar block in soft embalmed Thiel cadavers

© American Society of Regional Anesthesia & Pain Medicine 2022. No commercial reuse. See rights and permissions. Published by BMJ. INTRODUCTION Spread after erector spinae plane (ESP) block and retrolaminar (RL) block is unreliable. Combined ESP and RL injection is associated with greater paravertebral spread compared with ESP injection in the Thiel cadaver. We now hypothesize that combined injection is more extensive than RL injection. Our primary objective was to compare the spread of dye to the paravertebral and epidural spaces, dorsal and ventral rami, intercostal nerves and sympathetic chain. The primary end point was the number of ipsilateral stained structures.