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Edward R. Laws, Jr., M.D., and Edward H. Bertram III, M.D.
Departments of Neurosurgery and Neurology, University of Virginia Health Sciences Center, Charlottesville, Virginia
There has been a considerable increase in interest in the surgical management of intractable epilepsy in children. Better methods of diagnosis and improved knowledge of natural history and results of surgery have been major factors in this phenomenon. The results of surgery in 76 patients who were 19 years of age or younger are reported. Success rates, defined as no postoperative seizures with loss of consciousness (Engel Grades I and II) were 78% in 52 patients treated by temporal lobectomy, 75% in eight patients who had extratemporal resections, 80% in 10 children treated by hemispherectomy, and 33% in three patients treated by corpus callosotomy.
Key Words * epilepsy * pediatric neurosurgery * temporal lobectomy * hemispherectomy * corpus callosotomy
The application of the principles of surgical management of intractable epilepsy to children is a relatively recent phenomenon.[2,4] The previous supposition was that a child might "outgrow" a seizure disorder or that passage through puberty might produce unpredictable changes in the seizure disorder. Another problem in identifying suitable pediatric candidates for epilepsy surgery was related to the peculiarities of the surface electroencephalography in children with partial complex epilepsy. Focal activity often appeared to be located more posteriorly than was considered safe for surgical resection. With increased experience in diagnosis, therapy, and evaluation of the natural history of focal epilepsy in children, it has become evident that early surgical intervention in suitable patients leads to excellent results. Successful surgery can alter progressive psychological and intellectual impairment, reduce undesirable side-effects of medical therapy, and allow children with seizures to anticipate a normal and productive life.[1,2]
A National Institutes of Health Consensus Conference in 1990 carefully evaluated the subject of surgical management of intractable epilepsy. Criteria for evaluation and selection of surgical candidates were clarified, the efficacy of the surgical approaches was critically assessed, and a recommendation was made that these techniques be actively extended to the management of children with intractable epilepsy.
The surgical procedures used in children and the conditions for which they are recommended are presented in Table 1.
CLINICAL MATERIAL AND METHODS
This report discusses the experience of an evolving surgical approach to the management of seizures in children. This is a personal series based on cooperative work with epilepsy groups at the Johns Hopkins University Hospital (19701972), Mayo Clinic (19721987), George Washington University (19871992), and the University of Virginia (19921994). Of a total of 360 surgical procedures in patients with epilepsy, 76 were performed in patients who were 19 years of age or younger at the time of surgery. This group of 76 patients forms the basis for this report.
RESULTS
The various procedures performed in this patient group are specified in Table 2. The patients who underwent hemispherectomy (Fig. 1) suffered from the various pathological conditions for which this technique can play a major role.[3,5] Several patients with Rasmussen's syndrome were evaluated, but surgery usually was not recommended.
Fig. 1. Representative hemispherectomy specimen obtained in a 6-year-old boy who has been seizure free for many years, graduated from college, and is leading a normal life.
Structural lesions presenting as intractable seizures were encountered in 19% of patients, and the nature of these lesions is specified in Table 3.
The majority of patients had partial complex epilepsy and were treated by temporal lobectomy;[1] most of these patients were included in a prior report.[6] When postoperative success is defined as no seizures with loss of consciousness (Engel Grades I and II) satisfactory results are found in 70% to 80% of patients undergoing temporal lobectomy, 60% to 80% of those who had extratemporal resections, 70% to 80% of patients undergoing hemispherectomy, and approximately 40% to 50% of those treated with section of the corpus callosum.[7] The results for our series for patients followed at least 2 years are given in Table 4.
DISCUSSION
The results of standard methods of surgical management are similar in adults and children. The advent of more sophisticated methods of diagnosis has increased the accuracy of diagnosis and the reliability of selection of surgical candidates likely to benefit. The ability to use modern methods of functional imaging such as positron emission tomography, single-photon emission computerized tomography and functional magnetic resonance imaging promises not only better surgical results, but has also shed new light on basic issues related to the developing brain, its organization, and its function. Advances in concepts and techniques of electrophysiological recording of seizures continue to be made and contribute greatly to accuracy of diagnosis and efficiency of surgical therapy.
It does appear that early surgical intervention in appropriate cases can arrest progressive deleterious changes in the developing brain. These include progressive epilepsy, mental retardation, behavioral disorders, and neurological deficit. Additionally, the plasticity and redundancy available in the developing brain allow children to compensate for brain resections that might not be advisable in adults.
The challenge for the surgeon is the accurate identification of optimum candidates. The seizure disorder must be intractable and preferably progressive, worsening over time. It must be refractory to a comprehensive evaluation of anticonvulsant drug therapy accomplished in a timely fashion. There should be a focal area of pathology or altered brain function. This can be evaluated by a number of different diagnostic modalities including electroencephalography, magnetoencephalography, ictal single-photon emission computerized tomography, positron emission tomography, magnetic resonance imaging, and functional magnetic resonance imaging. The synthesis of clinical, developmental, genetic, electrophysiological, imaging, metabolic, drug response, and natural history data should allow for increasingly accurate case selection. These advances, combined with refinements in surgical technique should lead to improved outcomes in this difficult group of pediatric patients with intractable seizure disorders.
References
1. Davidson S, Falconer MA: Outcome of surgery in 40 children with temporal-lobe epilepsy. Lancet 1:12601263, 1975
2. Duchowny MS: Pediatric epilepsy surgery: special considerations, in Wyler AR, Hermann BP (eds): The Surgical Management of Epilepsy. Boston:Butterworth-Heinemann, 1994, pp 171188
3. Falconer MA, Rushworth RG: Treatment of encephalotrigeminal angiomatosis (Sturge-Weber disease) by hemispherectomy. Arch Dis Child 35:433437, 1960
4. Goldring S: A method for surgical management of focal epilepsy, especially as it relates to children. J Neurosurg 49:344356, 1978
5. Krynauw RA: Infantile hemiplegia treated by removal of one cerebral hemisphere. S Afr MJ 24:539544, 1950
6. Meyer FB, Marsh WR, Laws ER Jr, et al: Temporal lobectomy in children with epilepsy. J Neurosurg 64:371376, 1986
7. Spencer SS, Spencer DS, Williamson PD, et al: Corpus callosotomy for epilepsy. I. Seizure effects. Neurology 38:1924, 1988
Manuscript received September 24, 1996.
Accepted in final form October 16, 1996.
Address reprint requests to: Edward R. Laws, Jr., M.D., Department of Neurosurgery, University of Virginia Health Sciences Center, Box 212, Charlottesville, Virginia 22908.
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