Suprapetrous infratemporal approach: a novel access to inferior amygdala and hippocampal lesions to minimize temporal lobe retraction

Introduction: Historically, access to the anteromedial temporal lobe has been achieved with transsylvian, subtemporal (STA), and transcortical approaches. Additionally, the supracerebellar infratentorial (SCIT) approach has revolutionized access to the medial temporal lobe posteriorly as it allows a direct route without transgression of brain but is limited in access to the head of the hippocampus and amygdala. In this study, we describe a novel technique to improve access to inferior amygdala and hippocampal head with the goal to minimize temporal lobe retraction called the suprapetrous infratemporal approach (SPIT). Cadaveric analyses were performed for this approach and intraoperative findings are presented.

Methods: Three formalin-fixed latex-colored anatomical specimens were utilized to perform the SPIT in one side and the and the traditional STA in the other side to evaluate differences in surgical exposure and technique. Two intraoperative case examples were provided to qualitatively demonstrate the degree of access to anteromedial lesions.

Results: The SPIT allowed direct access to the amygdala, eliminating the need for retraction of the temporal lobe and detachment of the temporal lobe from the dura thereby reducing tension on the vein of Labbé reducing the potential for temporal lobe venous congestion. The approach also provides the operator an anterosuperior surgical corridor similar to a mini-posterior petrosal view. SPIT was performed on two patients with mesial temporal lobe epilepsy due to the inferior amygdala lesion. The lesions were clearly visualized intraoperatively and successfully removed without any complications in both cases.

Conclusion : SPIT is a minimally invasive approach to anteromedial temporal lesions and provides an alternative surgical corridor when compared to traditional approaches to this region. Anatomical studies are provided to describe this approach. Moving forward, larger patient cohorts and outcome studies are needed to ensure the efficacy of the SPIT approach.