Near-Infrared Fluorescence Imaging With Indocyanine Green for Intraoperative Nerve Root Visualization in Spinal...

Area of Science:

• Neurosurgery
• Medical Imaging
• Surgical Navigation

Background:

• Iatrogenic nerve injury is a significant risk in endoscopic spinal surgery.
• Near-infrared (NIR) fluorescence imaging with indocyanine green (ICG) shows potential for intraoperative nerve root identification.

Purpose of the Study:

• To assess the feasibility, optimal dosing, safety, and mechanism of ICG fluorescence for nerve root visualization.
• To transition ICG fluorescence imaging from preclinical to clinical application in spinal surgery.

Main Methods:

• Preclinical studies in rabbits evaluated ICG doses and fluorescence signal quantification (SBR, MFI).
• Histological analysis investigated ICG retention mechanisms.
• A randomized controlled trial in 40 patients undergoing lumbar endoscopic surgery assessed ICG doses, fluorescence parameters, identification time, and outcomes.

Main Results:

• Preclinical studies indicated peak fluorescence signal at 3 hours post-injection, with ICG accumulating in nerve root microvasculature.
• Clinical trials showed the 2 mg/kg ICG dose yielded the highest SBR and MFI.
• ICG use reduced nerve root identification time without significant adverse events.

Conclusions:

• ICG fluorescence imaging is a feasible and safe technique for intraoperative nerve root visualization in endoscopic spinal surgery.
• ICG accumulation in nerve roots is likely due to the enhanced permeability and retention (EPR) effect.