Aim: To retrospectively study effectiveness of seizure control by resective epilepsy surgery, vagal nerve stimulator and ketogenic diet/modified Atkin diet in paediatric refractory epilepsy in Tuen Mun Hospital, HKSAR and what are the patients’ underlying etiologies.
Methods: Children and adolescences with medical refractory epilepsy underwent resective epilepsy surgery, vagal nerve stimulator and ketogenic diet/modified Atkin diet in Tuen Mun Hospital were recruited to study seizure outcome and underlying etiologies. We use Engel Classification to measure seizure outcome after epilepsy surgery: the seizure outcome of KD/MAD categorized into groups as: (1) seizure free; (2) > 75% seizure reduction; (3) 50%-75% seizure reduction; and (4) seizure no change. The seizure outcome after vagal nerve stimulator categorized into groups as: (1) > 50% seizure reduction; and (2) Seizure no change.
Results: Forty-four patients underwent resective epilepsy surgeries from 2001 to July 2018. Age for surgery ranged from 0.8-19 years (mean 10.4 years). Follow-up duration ranged from 0.1-16 years (mean: 6.2 years) included 22 patients who underwent temporal lobe surgeries; 14 patients underwent extra-temporal lobe surgeries; 4 patients underwent hypothalamic hamartoma resection; 3 patients underwent disconnection or hemisphereotomy. Seizure outcome in respective epilepsy surgery: in temporal lobe surgeries n = 22, Engel I: 82%; Engel II: 4%; Engel III: 8%; Engel IV: 8%. Etiologies: mesial temporal sclerosis: 41%; focal cortical dysplasia: 36%; developmental low grade tumor: 18%; gliosis: 5%. In extra-temporal lobe surgeries n = 15, Engel I: 64%; Engel III 36%. Etiologies: focal cortical dysplasia: 53%; cortical tuber 13%; ulgyria: 7%; haematoma/cavernous hamangioma: 13%, porencephaly: 7%; glial nodule: 7%. In hypothalamic hamartoma surgery, Engel I: 50%; Engel II: 25%; Engel IV: 25%. For disconnective surgery included 1 TPO disconnection & 2 hemispherotomy, Engel I: 33%; Engel II: 33%; Engel IV: 33%. Total 6 patients underwent vagal nerve stimulator implantation from 2014 to 2018. Three patients underwent re-implantation after VNS out of battery. Age of first implantation n = 6 ranged from 3-22 years (mean age: 16.5 years). Duration of follow up: ranged 1-5.5 years (mean 3.7 years).The underlying etiologies inlcuded post-FIRES epilepsy, bilateral mesial temporal sclerosis, lennox gastaut syndrome, 2 subcortical band heterotropia, symptomatic epilepsy with history of status epilepticus due to TBC1D24 mutation. Three patients had > 50% seizure reduction with etiologies included post-FIRES epilepsy, LGS, TBC1D24 mutation. Three patients with no change in seizure control with etiologies 2 subcortical band heterotropia, bilateral MTS. Twenty-one patients put on ketogenic diet/ modified Atkin diet from 2001 to July 2018. Age to start KD/MAD ranged from 0.3 year to 11 years (mean age: 5 years). Duration of follow up ranged from 2 months to 232 months (mean 32 months). Three patients became seizure free with etiologies as congenital CMV infection, Landau Kleffner Syndrome, suspected focal cortical dysplasia over TPO region in dominant hemisphere. Eight patients with > 75% seizure reduction with etiologies: Leigh’s disease (complex I&IV respiratory chain enzyme deficiency), 2 suspected neuro-metabolic disease, post-HIE epilepsy, familial HLH, SSADH deficiency, post-influenza encephalopathy epilepsy, focal epilepsy. Five patients with 50%-75% with etiologies: Ohtahara’s syndrome, post-HSV encephalitis, extensive right side fronto-central focal cortical dysplasia, 2 symptomatic generalised epilepsy. Five patients with seizure no change with etiologies: STXBP1 mutation, LGS, symptomatic epilepsy, 2 extensive focal/ hemi-cortical dysplasia, the latter two underwent epilepsy surgery with seizure improvement.
Conclusion: In view of better seizure outcome in surgery when compared with VNS and dietary treatment, refractory epilepsy patients with underlying lesion should consider epilepsy surgery. On the contrary, those with underlying metabolic or genetic disease and those with no definite focus or diffuse lesions should be considered for ketogenic diet or vagal nerve stimulator implantation.