Effects of dexmedetomidine combined with erector spinae plane block on intraoperative neuromonitoring during surgical correction for adult spinal deformity

We aim to explore the effects of the erector spinae plane block (ESPB) technique combined with dexmedetomidine administered systemically on somatosensory- and/or motor- evoked potential (SSEP and/or MEP) during surgical correction for adult spinal deformity (ASD). 88 patients were randomly allocated to two groups: the propofol-remifentanil based total intravenous anesthesia (TIVA) group (Group T), and the dexmedetomidine group (Group DE), which received dexmedetomidine intravenously at a rate of 0.5 μg kg⁻¹ h⁻¹ as an adjuvant to TIVA, along with bilateral bi-level single-shot ESPB using 0.2% ropivacaine. Bilateral bi-level single-shot ESPB was performed in Group DE. The depth of anesthesia was adjusted by varying the propofol infusion rate based on the bispectral (BIS), which was maintained between 40 and 60. Mean arterial pressure was maintained between 70 and 85 mmHg. In Group T, within-group analysis presented an inhibitory effect on MEP amplitude after surgical correction, which persisted for 30 min when compared to the baseline values. Between-group analysis demonstrated a statistically significant decrease in MEP amplitude after surgical correction, lasting for 30 min in Group T compared to Group DE. However, no significant differences were observed in SSEP. No patients experienced serious postoperative side effects. Dexmedetomidine adjuvant to TIVA, then followed by preemptive analgesia with ESPB does not exert inhibitory effects on SSEP/MEP in ASD surgery. However, suppressive effects on MEP amplitude were observed and persisted for at least 30 min in patients who receive only TIVA. Importantly, no post-operative side effects were observed in either group. Clinical Trial Registration: Chinese Clinical Trial Registry.cn; Identifier: ChiCTR2200057123.