Erector Spinae Plane Block Combined With General Anesthesia Versus General Anesthesia Alone in Spine Surgeries for Postoperative Pain, A Randomized Controlled Trial

In both groups, on arrival to the operation room, a multi-channel monitor will be attached to the patient to display continuous electrocardiogram (ECG) monitoring, heart rate (HR), non-invasive blood pressure, pulse oximeter, temperature probe, capnogram, and anesthetic gas analysis. An intravenous line will be secured, then lactated Ringer's solution will be started at 5 ml/kg/h. Ten minutes before induction of anesthesia, all patients will be premedicated with intravenous midazolam 0.02 mg/kg. Patients will be preoxygenated with 100% oxygen for 3 minutes. In both groups, induction of anesthesia will be carried out by intravenous administration of fentanyl 1 µg/kg, lidocaine 1.5 mg/kg, and propofol 2 mg/kg. After loss of verbal communication, 0.5 mg/kg atracurium will be administered. Intermittent positive pressure ventilation will be adjusted to maintain an end-tidal carbon dioxide partial pressure between 30 and 35 mmHg. Anesthesia will be maintained with 1-2% isoflurane, 0.1 mg/kg atracurium bolus doses will be administered every 20 minutes, and 0.5 µg/kg fentanyl will be administered every 30 minutes.

In the Erector Spinae Plane block (ESPB) group, after prone positioning and before surgery, Erector Spinae Plane Block will be performed bilaterally using a low-frequency curved ultrasound transducer placed in a longitudinal orientation 3 cm lateral to the spinous process one vertebral level above a predetermined marked surgical incision. An 8-cm 22-gauge block needle will be inserted in a cephalad to caudad direction until the tip lies in the interfascial plane below the erector spinae muscle; the block will be performed by injection of 20 ml of 0.25% bupivacaine. In both groups, fentanyl 1 µg/kg as rescue analgesia will be given based on hemodynamic parameters.

If the mean arterial blood pressure (MAP) has fallen below 65 mmHg, 5 mg of ephedrine will be administered, and an intravenous bolus of 0.5 mg of atropine will be administered in case of bradycardia if the heart rate ≤50 bpm. The blood pressure will return to the baseline value before surgical field closure. Then at the end of surgery, the isoflurane vaporizer will be turned off, and the muscle relaxant will be reversed with neostigmine 0.04 mg/kg and atropine 0.02 mg/kg. The endotracheal tube will be removed after the patient regains consciousness and full muscle power, breathes spontaneously, and responds to verbal commands. Isoflurane consumption was measured at the end of surgery.

Postoperative pain management:

A standardized analgesic regimen will be prescribed in the postoperative period. All patients will receive 1 gm of paracetamol every 6 h. If the numeric rating scale (NRS) is more than 3, intravenous morphine 3mg will be administered by an investigator blinded to group assignment.