Hemispherectomy: A review

First described in the 1920s, hemispherectomies (HS) had an extraordinary impact on the practice of neurosurgery as well as on the understanding of the developing nervous system. Few people would have predicted that a patient would survive such an extensive resection. That patients survived, and that the effects were not much worse than a severe stroke, dramatically challenged the fledgling neuroscience community. Here was a clinical result that called for an entire reexamination of the theories of localization, plasticity, handedness, and development. However, the operation failed its initial goal. HS could not cure brain cancer, and it offered no long-term survival benefit. The procedure would have disappeared except that another pioneer, McKenzie in Canada, saw that Dandy's 'last resort' operation for brain tumors could be applied to infantile hemiplegia and intractable epilepsy. Krynauw's description of 12 cases subsequently became the basis for the use of HS in children. Initial results were remarkable and gratifying. Seizures stopped. Children became free of medications and could reestablish happy lives. This picture of enthusiasm gradually changed to concern, then outright pessimism, after long-term studies indicated that the initial period of wellness could be followed in 6-8 years by a progressive neurological decline and death. Autopsies showed brain stem shifts and slow intracranial bleeding leading to hydrocephalus and hemosiderosis. The literature today contains numerous warnings about the sequelae of HS. The third generation of HS began in the 1970s. Qualified observers considered that the long-term side effects could be surgically managed. Moreover, the operation remained the viable option for the relief of intractable seizures. Several third-generation case series recently have been published. It is important to compare results, for there are notable differences in the surgical approach at various centers. Even within a given series, surgical methods, including anesthetic techniques, may change as reports appear and personal contacts share information.