Impact of intraoperative MRI on pediatric epilepsy surgery for focal cortical dysplasia.

BACKGROUND

Complete resection is essential for achieving seizure freedom in children with drug-resistant epilepsy due to focal cortical dysplasia (FCD). However, identifying altered structures intraoperatively can be challenging, potentially leading to reoperations. This study assessed the impact of intraoperative MRI (iMRI).

METHODS

We conducted a single-center retrospective study at Alder Children's Hospital from 2013 to 2022. The study included all children diagnosed with FCD, analyzing demographics, iMRI use, the rate of continued iMRI-guided surgery and reoperations, histology, and seizure outcomes at 1-year follow-up.

RESULTS

Thirty-two pediatric patients (median age: 10 years, 21 males and 11 females) underwent surgery for FCD. Of them 8 (25 %) had FCD Type I, 19 (59.4 %) had FCD Type II, and 1 patient (3.1 %) had FCD Type III. iMRI was used in 27 patients (84.4 %), and 17 (63 %) of these patients required further iMRI-guided surgery. Four patients underwent reoperation in a separate session. At 1-year follow-up, seizure outcomes in the iMRI group were Engel I in 15 patients (71.4 %), Engel II in 4 (19 %), and Engel III and IV in 1 patient (4.8 %) each. Five patients (15.6 %) had superficially localized lesions and underwent surgery without iMRI. None of them required reoperation, and four (80 %) were seizure-free at 1 year. Seven patients were lost to follow-up.

CONCLUSION

iMRI plays a significant role in identifying residual epileptogenic tissue in surgery for FCD, influencing surgical decisions and leading to additional iMRI-guided resections. Most patients with iMRI-guided surgery achieved favorable seizure outcomes (Engel I) at 1 year of follow-up. Long-term follow-up is needed to validate these findings and to confirm sustained seizure control.