Hemimegalencephalia: An overview of relevant literature and experience in surgical treatment of 5 affected children
Abstract
Hemimegalencephalia is a dysplasia deforming the cerebral cortex and causing asymmetry of the cerebral hemispheres. The dominating feature of an MR image is the abnormal size of one of the hemispheres, ventriculomegaly and abnormality of gyrification.
The disease can exist in isolation or in connection with other lesions forming part of a neurocutaneous disease. The three-grade classification (I-III) reflects the severity of affection and prognosis.
The disease is manifested as early as in childhood, mostly in the form of refractory epileptic seizures and other psychological and neurological symptoms. If conservative treatment fails, surgical removal of the affected area is the method of choice: lobar/multilobar resection (A), subpial transsection in the motor area (B), decortication (C), and functional or anatomic hemispherectomy (fHSE or aHSE, respectively).
The authors report the course and results of surgical treatment of five children with the hemimegalencephalia diagnosis. The clinical picture of all the five children was dominated by refractory epileptic seizures, psycho-motor development disorder and additional neurologic symptoms: contralateral hemiparesis, myoclonal jerks etc.
Surgery was performed in all the patients: calosotomy and functional hemispherectomy extended in the second time, subpial transsection of the motor area with multilobar resection, subpial transsection of the motor area with lobar resection and decortication, anatomic hemispherectomy, functional hemispherectomy in the second time complemented with anatomic hemispherectomy. In all cases, the treatment resulted in lower frequency of EP seizures, and the progress of PM slightly decelerated in three patients, while the surgery had no effect in another two patients with stagnating PM development.
Thirty-day morbidity and mortality in the set was nil. The authors refer to hemimegalencephalia as a relatively rare neurosurgical disease.
They point out that also the relatively invasive surgery which is only sporadically used today, has its place in the treatment of hemimegalencephalia.