What is the recommended electrode placement for recording cortical SSEPs during intraoperative monitoring of the thoracolumbar spinal cord?

When recording cortical somatosensory evoked potentials (SSEPs) during intraoperative monitoring of the thoracolumbar spinal cord, the recommended electrode placement is critical for obtaining accurate and reliable data. The correct choice of placing the electrode 2 cm posterior to Cz leverages the International 10-20 system of electrode placement, which is designed to ensure that the recording captures electrical activity in the areas of the brain that process sensory information from the lower parts of the body, including the thoracolumbar region.

This positioning, specifically posterior to Cz, aligns with the expected topography of sensory processing in the brain, allowing for effective monitoring of pathways that involve the sensory cortex. The choice ensures that the electrodes are strategically placed over the somatosensory area that is responsible for receiving input from the thoracolumbar region, thus enhancing the chances of detecting any changes or abnormalities in these pathways during surgical procedures.

In contrast, placements such as 2 cm anterior to Cz or at other specified anterior or lateral positions may not effectively capture the required sensory data, as these regions are less involved in processing sensory input from the thoracolumbar spine. Accurate monitoring of SSEPs is crucial during thoracic and lumbar surgical interventions to detect potential complications or