Accuracy of frameless robot-assisted stereoelectroencephalography depth electrode implantation using the neurolocate registration system in paediatric patients.

Background: We assessed the accuracy and performed a directional analysis of robot-assisted implantation of stereoelectroencephalography (SEEG) depth electrodes in children using the frameless neurolocate 3D registration module.

Methods: Thirteen children with epilepsy undergoing stereotactic robot-assisted insertion of SEEG electrodes were included. Six children were operated on with standard frame-based registration while 7 with the use of the frameless neurolocate registration module. Accuracy and directional analysis of orthogonal and oblique electrodes were assessed by calculating the absolute error, the radial error, the angle error, and the Euclidean distance.

Results: Of 172 electrodes 89 were implanted in the 6 standard frame-based mode patients and 83 in the 7 neurolocate patients. The overall mean age was 12.2 ± 4.4 years (range 2-17). The mean number of electrodes in each patient was 13.2 ± 2.04 (range 9-17). The median radial error of electrode placement in the neurolocate patients (1.08 mm, [IQR: 1.26]) was significantly less when compared with standard frame-based mode patients (1.49 mm, [IQR 1.25)];  = 0.04). The same applies to the median angle error which was in the neurolocate group 1.61° [IQR: 1.46] and in the standard frame-based group 2.16° [IQR: 2.09];  = 0.019. Directional analysis of electrode trajectories in the neurolocate group showed that in the x-axis the median absolute error of orthogonal electrodes (0.4 mm, [IQR: 0.475]) was less when compared with oblique electrodes (0.7 mm, [IQR: 1.2];  = 0.007). In the standard frame-based mode group in the y-axis, the median absolute error of orthogonal electrodes (0.7 mm, [IQR: 1.3]) was less compared with oblique electrodes (1.25 mm, [IQR: 1.6];  = 0.03).

Conclusion: In paediatric patients, robot-assisted SEEG depth electrode implantation with the non-invasive and easy-to-use frameless neurolocate registration module is a consistent and accurate procedure.