Precision study of stereotactic electroencephalograph electrode implantation under neuronavigation in children with refractory epilepsy

Objective To explore the accuracy of stereotactic electroencephalograph (SEEG) electrode implantation under neuronavigation in children with refractory epilepsy. Methods Twenty-one children with refractory epilepsy underwent SEEG electrode implantation for identification of epileptogenic zone at Neurosurgery Department of Shenzhen Children's Hospital from March 2016 to December 2017 and were retrospective enrolled into this study MR surface registration and CT registration with anatomic markers were used for the electrode implantation. The accuracy of electrode implantation was compared between the 2 registration methods. The correlation between the depth of electrode implantation (the distance from cortical entry point to target) and the error of target and the error of entry point was analyzed. Results A total of 139 electrodes were implanted in 21 patients. Among them, 56 electrodes were implanted by MR surface registration method, and 83 implanted electrodes were placed by CT anatomical marker registration method. The registration time, registration error, electrode entry error and target error of MR Surface registration group were (37±9) min, (2.3±0.5) mm, (2.7±0.7) mm and (3.1±0.5) mm; those in anatomical marker registration group were (10±4) min, (1.1±0.3) mm, (1.5±0.5) mm, (2.2±0.6) mm respectively. The differences were statistically significant (all P<0.05) in the comparison between the 2 groups. In 139 electrodes, the electrode implantation depth was (4.7±1.7) mm, the entry point error was (2.1±1.3) mm, and the target error was (2.8±1.2) mm. Correlation analysis showed that the depth of electrode implantation was positively correlated with the target error (r=0.57, P=0.034), and there was no correlation with the error of the entry point (r=0.27, P=0.121). None of the patients had complications such as bleeding and infection after electrode implantation. After epileptogenic zonectomy, all patients were followed up for 6 months and included 20 cases as Engel Ⅰ and 1 case as Engel Ⅱ. Conclusion In children with refractory epilepsy, the accuracy of SEEG electrode implantation under neuronavigation seems to be relatively high. Compared with MR surface registration method, the registration efficiency and the accuracy of electrode implantation can be improved by using CT anatomical marker registration. Key words: Epilepsy; Child; Error; Neuronavigation; Stereoelectroencephalography