The Erector Spinae Plane (ESP) block or spinal erector block was first described in September 2016 by a Canadian team. It's a block that was initially used for the treatment of chronic thoracic neuropathic pain. The ESP block is one of the inter-fascicular blocks and it's an easy-to-perform technique.In the literature, it has been reported that Lumbar ESPB provides effective analgesia after a hip surgery.

The purpose of this prospective randomized study was to compare the analgesic effects of the ultrasound-guided lumbar Erector Spinae Plane block on postoperative pain management versus the multimodal analgesia after total hip arthroplasty.

Patients aged more than 18 years, ASA I-III scheduled for primary total hip arthroplasty with lateral approach and under general anesthesia Patients were randomly assigned, into 1 of 2 groups, namely, group ESPBL and group Placebo, using sealed envelopes

• For ESPBL group: Lumbar ESP block performed after anesthesia induction. A low-frequency ultrasound probe will be placed longitudinally 2-3 cm lateral to the L4 transverse process. Erector spinae muscle will be visualized on the hyperechoic transverse process. The block needle (100 mm, 22G) will be inserted cranio-caudal direction and following confirmation of the correct position of the needle, between the erectorspinae muscle and the transverse process,30 ml of local anesthetic (0.25% bupivacaine/0.2% ropivacaine) will be administered for the block.
• For Placebo group: patients had multimodal analgesia without lumbar ESP block Patients will be transferred to continuous care unit for 24 hours.

Post-operative analgesia will include:

1. Paracetamol 1g IV every 8 hours for 1 day then oral paracetamol 1g every 8 hours for 4 weeks.
2. Diclofenac sodium(50mg) 1 tablet x 2 per day for 5 days.
3. PCA morphine (Patient Controlled Analgesia), as a rescue analgesia, programmed as: Bolus of 1mg/ refractory period of 10 min/ maximum dose set up at 10mg every 12h.

The primary outcome of the study is to compare postoperative opioids consumption in the first 24 postoperative hours.

Secondary endpoints:

Secondary outcomes are: intraoperative opioid consumption, postoperative pain scores, sitting position and adverse effects related to opioids.

Inclusion Criteria:

• primary total hip arthroplasty with lateral approach and under general anesthesia .

Exclusion Criteria:

• • Contraindication or refusal to regional anesthesia

  • Contraindication to non-steroidal anti-inflammatory (NSAID's)
  • Allergy to opioids
  • Allergy to paracetamol
  • Creatinine clearance < 30ml/min
  • Weight<50 kg or >100kg
  • Psychiatric disorders and difficulty of communication
  • Lower limb neurological deficit
  • Patients undergoing bilateral or revision total hip replacement