What is a standard temporal lobectomy? A survey of epilepsy neurosurgeons

Anterior temporal lobectomy (ATL) is the most common surgical procedure used to treat drug-resistant epilepsy. ATL fundamentally involves removal of the anterior temporal neocortex and mesial structures; however, there may be substantial variability in resection extent across surgeons. The objective of this study was to evaluate the practice patterns and ATL surgical techniques of epilepsy surgeons.

An anonymous REDCap-based survey of epilepsy neurosurgeons was conducted to collect demographic and resection data. Resection extent was assessed by asking participants to draw their typical resection limits on six 2-dimensional cartoons of the temporal lobe. Individual maps were superimposed over the base template image with a pixel size equivalent to 0.25 mm2 to create cohort-level resection maps, with pixel intensity reflecting the number of respondents who selected that region.

Fifty responses were received that included image sets suitable for analysis. The mean ± SD age of respondents was 44.8 ± 7.6 years, they had been in practice for a mean of 9.9 ± 7.6 years, and 89.7% had completed an epilepsy-related fellowship. Significant variability was noted in the posterior extent of neocortical resection and resection of the superior temporal gyrus, which was more extensive on the right side. Variability was likewise observed in the parahippocampal gyrus and piriform cortex. While nearly all respondents included the inferior amygdala, there was less consistency in resection of the dorsal amygdala. Longer duration of practice was associated with significantly decreased neocortical resection. Higher annual ATL volume was positively correlated with more superior resection in the region of the inferior circular sulcus as well as more posterior neocortical resection, particularly along the inferior temporal gyrus.

Despite overall agreement on the general extent of anterior temporal resection and generally more extensive resections on the right side, this study highlights the substantial variability in both lateral neocortical and mesial structure resection.