Clinical and Imaging Evaluation of Transuncus Selective Amygdalohippocampectomy

Various reports have described the transuncus (TU) approach as a selective route to the amygdala and hippocampus, but this approach has not yet been submitted to solid postoperative imaging analysis. The objective of this study was to evaluate the anatomy, surgical technique, postoperative imaging analysis, and outcome in a series of patients with temporal lobe epilepsy who underwent selective amigdalohippocampectomy via a TU approach.

This was a prospective study of 25 consecutive patients who underwent selective amigdalohippocampectomy through a TU approach. The temporal stem and temporal pole were evaluated through different modalities of 3-Tesla magnetic resonance imaging, including tractography of optic radiation (OR), uncinate fascicle, and inferior fronto-occipital fascicle. Visual field analysis was performed with automated perimetry.

The mean age was 40 ± 8.21 years, and mean follow-up was 26.44 + 12.58 months. Postoperatively, 21 patients (84%) were classified as Engel I (good seizure control). Diffusion tensor imaging (DTI) data showed that 78.2% of patients had some structural damage to the temporal stem and fibers of the uncinate fascicle were identified postoperatively in only 3 patients (13.04%). The inferior fronto-occipital fascicle was identified in 18 patients (78.3%); however, subsequent DTI analysis of the remaining fibers showed them to be damaged. Integrity of the OR did not differ between these 2 groups.

A TU approach is a feasible and efficient approach to selective amigdalohippocampectomy for surgical treatment of temporal lobe epilepsy. Postoperative DTI analysis suggests that a TU approach results in more injury to the temporal stem and its associated white matter fiber tracts than expected by previous anatomic studies; however, it was efficient in preserving OR.