Surgical Interruption of the Conduction Pathways for the Control of Intractable Epilepsy

Abstract

The definition of the focus of origin and its ablation by open operative surgery of cortical or immediately subcortical lesions has been the foundation stone of surgical endeavour for the control of epilepsy when the disciplined use of drugs has failed. We have just enjoyed an exposition of the classical pioneer work of Penfield and Rasmussen, Talairach and his colleagues, and of the painstaking studies and long-term results from their departments. The success of these procedures, particularly in temporal lobe epilepsy, has been gratifying and moreover they have led to a broad advance in knowledge even beyond that of epilepsy. It would be presumptuous of me to consider for a moment that stereotaxy and the Interruption of conduction pathways may have a rival place in this particular field, although no doubt Professor Narabayashi will make a case for it in the next contribution. Indeed, some have claimed that when the pattern of seizures suggests a focal origin which cannot be defined unequivocally by all commonly used methods of investigation, even operative exploration, then a stereotactic lesion in the ipsilateral hemisphere is indicated. This was the basis of the original experimental animal work of Jinnai¹ and his co-workers and the application of this knowledge led to his clinical experience with patients and his well-known lesion in the field of Forel. The results were encouraging and their more recent long term follow-up studies support their findings although they stress the need for accurate placement and size of lesion to avoid side effects and achieve significant reduction of the frequency and severity of seizures². In frequent severe grand mal and minor disabling seizures there is also the difficulty of established secondary foci which may be inaccessible to open operation.