A retrospective study comparing preoperative evaluations and postoperative outcomes in paediatric and adult patients undergoing surgical resection for refractory epilepsy

Purpose: To review and compare the preoperative characteristics and postsurgical outcomes in paediatric and adult patients who underwent surgical resections from 2001 to 2009.

Methods: Combined data from noninvasive measures such as ictal semiology, interictal/ictal scalp EEGs, MRI and SPECT were utilised to identify the epileptogenic zones (EZ). When noninvasive investigations produced inconclusive or inconsistent findings, patients underwent intracranial EEG monitoring. Resective micro-surgical procedures were conducted according to the results of the anatomo-electro-clinical investigations and were carried out to remove the EZ. We then followed up 222 paediatric (≤18 years old) and 100 adult patients (≥19 years old) for 1-9 years postoperatively.

Results: The mean age of seizure onset in paediatric group was significantly lower than that in adult group. 95 (43%) of the paediatric and 42 (42%) of the adult patients required long-term intracranial EEG recording. 54 (24.3%) of the paediatric and 62 (62%) of the adult patients were found to have temporal lobe epilepsy (TLE), while 149 (67.1%) of the paediatric and 37 (37.0%) of the adult patients had extra-temporal lobe epilepsy (ETLE) (p=0.000). 19 (8.6%) of the paediatric patients and 1 (1%) adult patient had hemispheric lesions (p=0.009). 148 (66.7%) of the paediatric and 61 (61.0%) of the adult patients were seizure-free during the follow-up period. 17 of 19 (89.5%) children who underwent hemispherectomy were seizure-free. In both paediatric and adult groups, the surgical outcome for patients with TLE was significantly better than that of patients with ETLE (p=0.018 in children, p=0.029 in adults). Both the location of EZs and seizure-free ratio were significantly different (p<0.001) between the preadolescent (≤12 years old) and adolescent (13-18 years old) group. Hippocampal sclerosis was the most common pathologic finding in patients with TLE in both groups, and was followed by focal cortical dysplasia. In patients with TLE, the proportion of tumour was significantly higher in the paediatric than the adult group (25.9% vs. 10%, p=0.021).

Conclusion: Paediatric patients with refractory seizures had more extratemporal or hemispheric resectable epileptogenic foci and fewer temporal foci than adults. Our study demonstrates that resective surgery is an effective and safe early intervention in strictly selected paediatric patients with refractory epilepsy.