Presurgical evaluation and postoperative seizure-outcome in children and adolescents with intracranial tumors and drug resistant focal epilepsy

Objective: Patients with intractable focal epilepsy due to intracranial tumors are excellent candidates for epilepsy surgery. According to the literature the percentage of seizure-free patients post surgery varies between 65–90%. Incomplete tumor resection and/or insufficient removal of tumor-associated focal cortical dysplasia are risk factors for good seizure outcome. Role of invasive diagnostic is not fully established yet.

Methods: Retrospective evaluation of data of 43 patients with intracranial tumors (out of 308 patients, who received epilepsy surgery between September 1998 and October 2010at the Epilepsy Center for Children and Adolescents, Schoen Klinik Vogtareuth)

Results: Age of onset of epilepsy: 5.1yrs (1m.-11), age at surgery: 10.8yrs (2–28), post-surgical follow-up: 68 mths (5.3–147). localisation of epilepsy: temporal 19/43, temporal plus 15/43, extratemporal 9/43. Invasive recordings: 3/43. histology: ganglioglioma 27/43, DNET 7/43, astrocytoma 2/43, misc. 3/43, pending 4/43. post-surgical seizure outcome: seizure-free 26/43, only aura 8/43, >90% seizure reduction 4/43, >50% seizure reduction 1/43, unchanged 1/43, pending 1/43. Reasons for surgical failure: incomplete resection of tumor (planned to avoid functional deficit/unplanned) 3/6, incomplete resection of tumor-associated focal cortical dysplasia 2/6, unknown 1/6.

Conclusion: Success of epilepsy surgery in our series is comparable to those in other publications. Reasons for surgical failure were incomplete resection of tumor or tumor-associated focal cortical dysplasia. Existence of tumor-associated focal cortical dysplasia, which might be undetected by standard resolution MRI should be considered in presurgical evaluation and resection planning in patients with drug resistant focal epilepsy to increase the chances for complete seizure relief.