Local anesthetic spread into the paravertebral space with two types of quadratus lumborum blocks: a crossover volunteer study

Purpose Previous work showed that 20 mL of local anesthetic (LA) did not spread into the paravertebral space (PVS) via the intramuscular quadratus lumborum block (QLBi). If spread of LA into the PVS can be achieved by increasing the total LA volume, QLBi can be more effective. We hypothesized that a larger volume of LA for the QLBi would spread into the PVS.