Spinal cord monitoring: basic principles and experimental aspects

Area of Science:

• Neuroscience
• Surgical Monitoring
• Spinal Cord Injury

Background:

• Spinal cord evoked potentials (SCEP) are utilized in Japan for intraoperative spinal cord monitoring.
• Understanding SCEP's sensitivity to spinal cord injury is crucial for surgical safety.

Purpose of the Study:

• To investigate how spinal cord evoked potentials (SCEP) reflect injurious effects on the spinal cord.
• To determine the critical thresholds for spinal cord distraction and compression impacting SCEP.
• To evaluate the combined effects of compression with hypotension or hypoxia on SCEP.

Main Methods:

• Animal experiments were conducted to assess spinal cord distraction, compression, and combined insults.
• Spinal cord potentials were recorded near the conus medullaris following rostral spinal cord stimulation.
• Comparative analysis of SCEP and spinal somatosensory evoked potentials (SEP) was performed.

Main Results:

• A critical point of spinal cord compression or distraction was identified, leading to significant SCEP amplitude decrease.
• Acute hypotension combined with moderate compression heightened the risk of spinal cord insult.
• SCEP demonstrated higher sensitivity than spinal SEP in detecting hazardous spinal cord effects.

Conclusions:

• Repetitive SCEP monitoring and rapid surgical feedback are essential for intraoperative spinal cord safety.
• Hypotension must be carefully avoided in cases of spinal cord compression.
• SCEP and spinal SEP can be used interchangeably, with SCEP offering superior sensitivity for detecting adverse events.