Background and Aims The erector spinae plane (ESP) block was described in 2016 by Forero et al. It involves the injection of local anesthetic into the interfascial plane, deep to erector spinae muscle, allowing the blockade of the dorsal and ventral rami of the thoracic spinal nerves. It was initially proposed for analgesia of costal fractures, pulmonary lobectomy and thoracic vertebrae. The ESP block (ESPB) could probably be extended to a large number of surgical procedures.

Methods After ethical commitee approval and informed consent, 80 patients were included in this prospective, single blind, monocentric RCT for lombar spinal stenosis surgery (LSSS) under general anesthesia: 40 patients with ESPB, 40 patients with local infiltration (LI) by the surgeon. The current interim reporting is based on 28 patients in ESPB and 28 in LI. Piritramide consumption was followed. The ESPB was realized on T12 and ultrasound-guided (chirocaine 0.25%+ epinephrine 1:200.000 4 mg/kg). The control group was injected at the same concentration by the surgeon. Complementary analgesia was realized with Patient Controlled Analgesia (Piritramide), paracetamol and ketorolac.

Results After performing a T-test to compare the means of piritramide consumption at day 1, we did not find any significant difference between the 2 groups (ESPB 12.9 mg versus LI 14.7 mg, p=0.55). A Mann-Withney U-test was also performed and did not show any difference.

Conclusions After collecting data from 70% of the population, we cannot conclude that there is a benefit of ESPB over LI by the surgeon.