Hemimegalencephaly and Intractable Epilepsy: Complications of Hemispherectomy and Their Correlations with the Surgical Technique

Abstract

Hemispherectomy is required in most cases of hemimegalencephaly in order to control epilepsy refractory to medical treatment. Although there is a general agreement on the effectiveness of the procedure in controlling the seizure disorder, the choice of the surgical technique is still a subject of debate. In particular, anatomical hemispherectomy is blamed to be associated with a higher incidence of surgical complications, namely hydrocephalus and hemosiderosis, than other less ablative operations such as functional hemispherectomies. A series of 15 children with hemimegalencephaly, who had undergone anatomical hemispherectomy (11 cases), functional hemispherectomy (2 cases), and hemidecortication (2 cases) at the Pediatric Neurosurgery Section, Catholic University Medical School, Rome, is reported. Twelve of these patients presented with one or more complications in their postoperative course. Temporary complications, which resolved spontaneously or following medical therapy, included fever, wound breakdown, worsening of preoperative motor deficit, unilateral third cranial nerve deficit, dystonia, and anemia. In 8 patients, postoperative complications led to a second surgical procedure. A CSF shunt was necessary in 5 children, to control a secondary hydrocephalus. Two subjects underwent a toilette of the residual cavity because of persisting chemical abnormalities in CSF parameters. In a child a cranioplasty procedure was necessary as a consequence of an infection of the hemicranial bone flap. There was no apparent correlation between the rate and the type of complications with a specific surgical procedure. On the other hand, the age factor appeared to play an important role in the occurrence of secondary hydrocephalus, as all 5 children with this complication were less than 9 months old at the time of the hemispherectomy. Surgical mortality was nil in this series.