BIS-Guided Sedation Protocol for Awake Endoscopic Lumbar Surgery

STUDY DESIGN: Retrospective, case-matched cohort. OBJECTIVE: Define a reproducible anesthetic protocol with bispectral index (BIS) targets that maintain airway safety and enable real-time dorsal root ganglion (DRG) feedback during awake endoscopic lumbar surgery without general endotracheal anesthesia (GETA). SUMMARY OF BACKGROUND DATA: Innovation has driven rapid growth in the field of endoscopic spine surgery, yet concern regarding dorsal root ganglion (DRG) injury continues to slow widespread adoption of spinal endoscopy. Awake surgery without GETA leverages real-time patient feedback for DRG monitoring, avoiding the consequences of general anesthesia. Maintaining the appropriate level of sedation is critical to awake surgery in order to prevent airway compromise from oversedation and patient movement or discomfort from undersedation. METHODS: Consecutive patients undergoing 1- or 2-level awake endoscopic transforaminal lumbar interbody fusion (TLIF) or discectomy were case-matched to patients undergoing minimally invasive (MIS) TLIF or microdiscectomy under GETA. Demographic, operative, anesthesia, and BIS data were analyzed. RESULTS: Thirty-three awake and 32 GETA cases were included. No awake cases converted to GETA. Propofol and opioid requirements were significantly lower with awake anesthesia. A BIS target window of 65±8 for awake endoscopic TLIF and of 70±4 for awake endoscopic discectomy was correlated with maintaining an optimal level of sedation and airway patency while minimizing discomfort and movement. CONCLUSION: The presented anesthetic protocol, coupled with BIS monitoring to titrate anesthesia, provides a reproducible framework for performing awake endoscopic spine surgery without GETA. The BIS thresholds we report are descriptive observations from a single-surgeon experience and should be interpreted as exploratory guidance. These findings are hypothesis-generating and highlight the need for prospective, multi-institutional validation.