Anesthesia Depth Monitoring with Bispectral Index in Spinal Cord Stimulation Device Implantation for Chronic Disorders of Consciousness: A Retrospective Study

Abstract Objective: To assess whether maintaining an appropriate depth of anesthesia using the Bispectral Index (BIS) could enhance outcomes following spinal cord stimulation (SCS) device implantation in patients with chronic disorders of consciousness (DoC). Methods: A total of 103 patients with DoC who underwent SCS implantation were reviewed between January 2019 and December 2021, of whom 83 met the inclusion and exclusion criteria. Patients were categorized into the BIS group (n = 45) and the non-BIS group (n = 38) based on whether BIS monitoring was used during the operation. Relevant data, such as disease course, cause, anesthesia, and operation time, were collected. Preoperative Coma Recovery Scale—Revised (CRS-R(preoperative)) score, postoperative CRS-R(24h), and postoperative CRS-R(3m) changes were recorded. Results: The CRS-R(3m) score was significantly higher in the BIS group than that in the non-BIS group (preoperative), with a statistically significant difference (p < 0.05). Furthermore, in the CRS-R(24h), the BIS group demonstrated a higher score than the non-BIS group, with a statistically significant difference noted (X2 = 8.787, p = 0.004). When assessing the improvement in consciousness in the multivariate logistic regression analysis model, it was revealed that the thalamus independently influenced the enhancement of consciousness (p < 0.05). Throughout the follow-up, one patient in the BIS group experienced a decline in consciousness from a minimally consciousness state (MCS)- to-vegetative state, whereas two patients in the non-BIS group passed away during the follow-up. Conclusion: For patients with DoC undergoing SCS implantation under general anesthesia, employing BIS monitoring during surgery to regulate the depth of sedation under general anesthesia can reduce propofol dosage and influence the brain network. Patients can benefit from improved hearing, as observed in the CRS-R(24h). We recommend using BIS to monitor the depth of anesthesia in patients with DoC to enhance overall patient outcomes.