Erector Spinae Block Vs Ketamine-based Multimodal Analgesia Protocol in Lumber Decompressive Surgery

Preoperatively, standard monitors will be attached (electrocardiogram, noninvasive blood pressure, and pulse oximetry) and intravenous access will be obtained. Dexamethasone will be administered at dose of 4 mg as an antiemetic prophylaxis.

Thirty min before induction of anesthesia all patients will receive 15 mg ketorolac and 1 gm paracetamol intravenously.

General anesthesia will be induced by 1 mcg/kg fentanyl and 2 mg/kg propofol titrated till loss of verbal response. Tracheal intubation will be facilitated by 0.5 mg/kg atracurium. General anesthesia will be maintained by isoflurane (end-tidal isoflurane concentration of 1-1.2%) in air-oxygen admixture.

Fentanyl boluses of 50 mcg will be given in case of inadequate analgesia (heart rate and or systolic blood pressure increase by 20% from the baseline in absence of other causes) Intraoperative hemodynamic management will be according to the discretion of the attending anesthetist.

Postoperatively, all Patients will receive oral 1 gm of paracetamol every 6 h and 400 mg ibuprofen every 8 h.

Pain assessments using NRS (Numerical Rating Scale) at rest and during movement at 0.5 , 4, 10, 18 and 24 h postoperatively. If NRS score is > 3, intravenous 2 mg bolus of morphine will be given.

Intravenous ondansetron 4 mg will be given to treat nausea or vomiting if occurs.

At the end of 24 h postoperatively, patient's quality of recovery will be assessed using QoR-15 questionnaire and patient's satisfaction.

Inclusion criteria

• American Society of Anesthesiologists (ASA) status of I-III
• scheduled for open lumber decompression surgery for degenerative stenosis or trauma involving 1or 2 levels without fusion.

Exclusion criteria

• Refusal to participate
• Contraindication for peripheral regional anesthesia such as infection and coagulopathy.
• Inability to comprehend the Numeric Rating Scale (NRS) or Patients who has cognitive function impairment
• Preoperative renal or hepatic insufficiency
• History of Opioid abuse.
• Allergy to any of the study drugs