Predictors of frame-based SEEG electrode implantation accuracy

Area of Science:

• Neurosurgery
• Neurology
• Medical Imaging

Background:

• Stereo-electroencephalography (SEEG) electrode accuracy factors are inconsistently reported.
• This study addresses SEEG implantation variables and factors for unsuccessful sub-lobar target sampling using traditional frame-based methods.

Purpose of the Study:

• To examine pre- and post-implantation variables influencing SEEG electrode accuracy.
• To identify factors contributing to unsuccessful sub-lobar target sampling.
• To provide a comprehensive reference for future SEEG implantations.

Main Methods:

• Analysis of consecutive frame-based SEEG implantations.
• Co-registration of pre-implantation MRI with post-implantation CT to determine planned vs. actual trajectories.
• Calculation of absolute, radial, and depth errors; multivariate regression models assessed predictive factors for errors and off-target electrodes.

Main Results:

• 629 electrodes from 50 patients analyzed; median absolute error 1.85 mm, radial error 1.56 mm.
• 8.59% of electrodes were off-target; 19.89% exceeded the 2 mm safety margin.
• Pre-implantation factors (trajectory angle, bone thickness, depth) and post-implantation factors (bone entry point localization error, bone thickness, depth) predicted radial errors.

Conclusions:

• Electrode target radial error is strongly predicted by implantation depth, bone thickness, and bone entry angle.
• Increased radial error is associated with missing the intended sub-lobar target.
• Further research is needed to understand the clinical implications of electrode inaccuracy.