Feasibility of lateral vs. transmuscular quadratus lumborum block in calves: a cadaver study

The quadratus lumborum block (QLB) may provide locoregional analgesia of the trunk.

To investigate the feasibility of 2 ultrasound-guided QLB approaches - lateral (QLB-L) and transmuscular (QLB-T) - in calf cadavers.

Ten calf cadavers underwent bilateral QLB at L1 using QLB-L (n = 5) or QLB-T (n = 5). Each cadaver received 0.4 mL/kg on one side and 0.6 mL/kg on the other. A 1:2 iohexol:methylene blue mixture was injected under ultrasound guidance. Computed tomography and gross dissection assessed craniocaudal spread and staining of ventral rami and sympathetic trunk segments.

The number of stained nerves was similar for both approaches. L1 and L2 were stained in all injections; T13 was stained in all but 1 QLB-L small-volume injection; T12 staining occurred most often with QLB-T small-volume injections (4/5) and in 2/5 injections in the remaining groups; T11 staining was limited (1/5 QLB-L and 2/5 QLB-T; both volumes); T10 to T4 staining occurred once (QLB-T large volume).

Both approaches were anatomically feasible in calf cadavers and produced injectate spread consistent with potential abdominal wall target coverage. Clinical trials are needed to determine analgesic efficacy and safety.