Effects of Intraoperative Nociception Monitoring during Adolescent Idiopathic Scoliosis Correction

Reducing postoperative opioid consumption has become a significant challenge in perioperative pain management, particularly within the framework of enhanced recovery after surgery protocols and the associated risk of prolonged opioid dependence. The primary objective of this study was to evaluate whether remifentanil administration guided by intraoperative nociception monitoring with the Analgesia Nociception Index (ANI) during surgery for adolescent idiopathic scoliosis (AIS), reduces postoperative morphine consumption at day 1. The secondary objective was the incidence of persistent postoperative pain 6 months following surgery.

The OpispANI study, a multicenter randomized controlled trial, was conducted between October 2020 and June 2023. Eligible children were randomly assigned to receive intraoperative remifentanil administration guided either by hemodynamic parameters (control group) or by the Analgesia Nociception Index (intervention group). Comparison of postoperative morphine use was adjusted to the use of non-opioid analgesics.

Overall 247 patients were included and 244 were randomized (120 in the ANI group and 123 in the control group). Postoperative morphine consumption at day one was similar in both groups (median [25-75 IQR]: 0.4 [0.3;0.8] vs. 0.4 [0.3;0.5] in the ANI and control groups, respectively; median difference [95% CI] = -0.005[-0.10; 0.09] mg.kg -1, p = 0.93). Intraoperative remifentanil administration decreased in the ANI group (mean difference [95 % CI]: 9.5 [4; 15] mcg.kg -1, P < 0.001). ANI-guided intraoperative remifentanil administration did not result in differences in secondary outcomes.

The administration of remifentanil guided by intraoperative nociception monitoring during AIS did not result in a reduction of postoperative opioid consumption.Registration on ClinicalTrials.gov: NCT04047225.