Intraoperative neuromonitoring findings after erector spinae plane block during posterior thoracolumbar fusion...

To investigate the potential adverse influence of erector spinae plane block (ESPB) on intraoperative neuromonitoring (IONM) during posterior spinal fusion for thoracolumbar fractures.

We conducted a retrospective review of patients who underwent posterior spinal fusion for thoracolumbar fractures between January 2018 and December 2022. Patients were categorized into ESPB and non-ESPB groups based on whether ESPB was administered. The primary endpoint was the change in transcranial motor evoked potential (Tc-MEP) and posterior tibial nerve somatosensory evoked potential (PTN-SEP) waveform derivation rates. Secondary outcomes included Tc-MEP and PTN-SEP alarm occurrence and postoperative neurological deterioration.

Overall, 154 patients were included in the final analysis (89 males, 65 females; mean age: 68.6 years; mean BMI: 22.1). There were 52 patients in the ESPB group and 102 in the non-ESPB group. No significant differences were observed in preoperative neurological findings between the two groups. ESPB did not significantly affect Tc-MEP or PTN-SEP waveform derivation rates. Tc-MEP alarms occurred in the quadriceps femoris muscle (QC) in 2 patients in the ESPB group, but not in the non-ESPB group. Both alarms occurred during T11-level procedures, and waveform recovery was obtained after surgical interruption. No postoperative motor deficits were noted in these patients.

ESPB did not significantly affect Tc-MEP or PTN-SEP rates. Two unexplained QC Tc-MEP alarms occurred only in the ESPB group. These findings do not establish a clinically actionable association between ESPB and IONM changes, but unexpected isolated QC Tc-MEP changes during surgery with ESPB should be interpreted cautiously.