The efficacy of ultrasound-guided erector spinae plane block (ESPB) versus freehand ESPB in postoperative pain management after lumbar spinal fusion surgery: a randomized, non-inferiority trial.

Purpose: Spine surgeries have experienced exponential growth over the past 2 decades. These surgeries are often accompanied by long and severe perioperative pain, presenting a significant management challenge. This study aims to assess and compare the efficacy of two techniques for postoperative pain (POP) management in lumbar spine surgeries: ultrasound-guided erector spinae plane block (ESPB) and intraoperative freehand ESPB.

Methods: In this prospective randomized non-inferiority trial (Registration Number: IRCT20221107056427N1), adult patients who were candidates for lumbar spinal fusion surgery were randomly divided into two groups: ultrasound-guided ESPB (n = 29) and freehand ESPB (n = 29). The primary outcomes were the total amount of morphine consumed during the first 24 h following the surgery and the numerical rating scale (NRS) pain score at various time points within the first 24 h following the surgery. The secondary outcome was the fentanyl used during surgery.

Results: Participants in the intraoperative freehand approach had considerably higher total morphine consumption in the first postoperative 24 h. The trend of NRS changes in both the ultrasound-guided ESPB group and the freehand ESPB group during the first 24 h after surgery showed a significant decrease. Still, there was no significant difference between the two groups. However, the first analgesic demand time was significantly shorter in the intraoperative freehand ESPB group compared to the ultrasound-guided approach.

Conclusion: According to our results, the ultrasound-guided approach of ESPB is more effective in POP management and opioid sparing in lumbar spinal fusion surgeries compared to the freehand approach. However, the data from this study are not sufficient to draw robust conclusions, and further randomized controlled trials with larger sample sizes are required to validate our results.