Comparison of the impact of the method of anesthesia on intraoperative nociceptive response during spine surgeries: Prospective randomized control trial.

BACKGROUND: Surgical intervention triggers nociception, whereas the main aim of anesthesia is to suppress nociceptive signal processing. The impact of different methods of anesthesia on the nociceptive response and their correlation with post-operative outcomes remains unclear. Regional anesthesia affects transduction, transmission, and modulation by interrupting the conduction of pain impulses by local anesthetics. Moreover, nerve blocks influence pain perception by reducing opioid consumption (OC), which helps prevent the development of pain sensitization and opioid tolerance. Owing to this mechanism, an essential balance between nociception and antinociception is sustained, and violation of this balance can lead to post-operative complications. AIM: To compare the impact of general anesthesia (GA) with erector spinae plane block (ESPB) versus GA without ESPB on intraoperative nociceptive response index (NRI), OC, post-operative pain intensity (PPI), and hyperalgesia in patients undergoing spine surgery. METHODS: This prospective, randomized controlled study was conducted in a clinical hospital with an affiliate university department, from December 2021 to November 2022. A total of 151 patients who underwent spine surgery via the posterior approach were randomly assigned to either the GA control group (CG) or the GA with ESPB study group (SG). OUTCOMES: NRI, OC, PPI, and hyperalgesia. This study was registered at ClinicalTrials.gov (identification number: NCT04697498 at December 12, 2020, https://clinicaltrials.gov/study/NCT04697498). RESULTS: Average NRI during surgery differed between groups: 0.66 ± 0.28 in the SG and 0.86 ± 0.19 in the CG. Amount of fentanyl and morphine was lower in the SG (1.84 ± 0.75 µg/kg; 5.62 ± 5.00 mg) compared with the CG (3.64 ± 1.2 µg/kg; 28.97 ± 9.75 mg), respectively. PPI at rest and during movement was higher in the CG after surgery than in the SG at all stages of observation. Mechanical pain threshold (MPT) did not differ before surgery: 21.05 ± 6.64 in the SG; 21.55 ± 6.06 in the CG. After surgery, the MPT was lower in the CG, 5.60 ± 1.93, than in the SG, 23.26 ± 6.8. NRI had the strongest negative correlation with hyperalgesia in comparison with other data. CONCLUSIONS: ESPB, as a component of GA, decreases NRI, OC, and PPI. As a result, it does not trigger hyperalgesia after spine surgery.