Abstracts

Ohtahara syndrome (OS) is a rare disorder characterised by the early occurrence in life of tonic spasms with burst-suppression on EEG. This syndrome is often associated with neuronal migration disorder and presents a very poor prognosis for seizure control and for psychomotor development. OS is known to be refractory to all available medical treatments, including corticoids. Surgery could be a therapeutic option, but the time and the type of surgery are still on discussion.
We report the case of a girl sustaining about one hundred epileptic spasms a day since the age of one month. Her EEG revealed a generalised burst-suppression pattern predominant on the left hemisphere. MRI revealed a left parieto-occipital megalencephaly with hypermetabolism on FDG/PET scan. She had no ocular contact, and suffered from a severe global hypotonia with a mildly increased tonus on the right side. Topiramate ( progressively increased until 11 mg/kg/day) improved partially the seizures but not the EEG nor the psychomotor development. An amobarbital test confirmed the left ictal dominance with temporary disappearance of abnormal epileptiform activities on the right hemisphere.
At eight months of age, we performed an [ldquo]a minima[rdquo] hemispherotomy without brain resection. A peri-insular approach was carried out going trough the frontal, parietal and temporal opercula. We entered in the lateral ventricle using neuronavigation (MKM, Zeiss, Germany) and from within, we disrupted the corpus callosum, the fimbria-fornix and the anterior commissure. There was no intra-operative complications and the child left the hospital a few days after surgery.
Immediately after surgery she developped an ocular contact with her parents and was smiling.
Epileptic spasms disappeared, however, topiramate remained unchanged.
One month postoperatively, right hemisphere EEG and FDG/PET scan were normalised with disappearance of the left hemisphere hypermetabolism. The baby gradually showed a spectacular psychomotor development.
In case of OS with unilateral cortical lesions, surgical disconnection may dramatically improved the patient[rsquo]s prognostic not only for seizure control, but also for psycho-motor development. This should be performed as early as possible.