Diffusion of local anesthetics after a lumbar ESPB within fascial planes towards nerve structures is a matter of debate.
The main objective of the study is to compare the incidence of sensory block between two techniques of needle placement (superficial or translaminar) during lumbar ESPB block.
Patients are treated with lumbar ESPB (randomized to superficial or translaminar), spinal anesthesia and multimodal analgesia.
The primary endpoint will be the incidence of numbness/reduced skin sensitivity to cold (ice test) in the area innervated by the lumbar plexus. Secondary outcomes are pain and analgesic's consumption, motor block, quality of recovery and discharge ability.