Abstracts

Rationale: The size of the cortical resection performed during temporal lobe surgery has been traditionally determined using linear methods. The most common approach was to resect 4.5 cm of cortex measuring from the tip of the temporal lobe posteriorly within the dominant hemisphere and 5.5 cm from the temporal tip in non-dominant hemisphere surgery. This paradigm did not take into account any individual, head size or age difference. We report on the usefulness of a non-linear paradigm in determining the size of the cortical resection in patients being submitted to cortico-amygdalo-hippocampectomy. Methods: Four hundred consecutive patients with refractory temporal lobe epilepsy and mesial temporal sclerosis submitted to cortico-amygdalo-hippocampectomy were studied. Age ranged from 3 to 57 years; patients of all races were included. All patients were operated under general anesthesia and submitted to a complete hippocampectomy. The posterior border of the cortical resection was determined by the position of the central artery as it exits from the sylvian fissure. Results: Nine patients had transient (1-3 weeks) receptive speech disorders. All of these patients were operated within the dominant hemisphere. In all of these patients, additional posterior temporal lobe cortex damage was documented by an early post-operative CT or MRI. No patient had a permanent speech deficit. Conclusions: Accurate study of the language representation maps obtained by the time all patients were operated under local anesthesia suggested that more then 98% of the temporal lobe speech related areas were located posterior to the exit point of the central artery. Using the central artery as a landmark represents a non-linear proportional system that takes care by itself of any age, size or race issues and proved to be efficacious in preserving speech in these patients.