Mechanisms and Risk Factors Contributing to Visual Field Deficits following Stereotactic Laser Amygdalohippocampotomy

Voets, Natalie L.; Alvarez, Ivan; Qiu, Deqiang; Leatherday, Christopher; Willie, Jon T.; Sotiropoulos, Stamatios; Gleichgerrcht, Ezequiel; Bonilha, Leonardo; Pedersen, Nigel; Kadom, Nadja; Saindane, Amit; Gross, Robert E.; Drane, Daniel L.

Abstract

Selective laser amygdalohippocampotomy (SLAH) is a minimally invasive surgical treatment for medial temporal lobe epilepsy. Visual field deficits (VFDs) are a significant potential complication. The objective of this study was to determine the relationship between VFDs and potential mechanisms of injury to the optic radiations and lateral geniculate nucleus. We performed a retrospective cross-sectional analysis of 3 patients (5.2%) who developed persistent VFDs after SLAH within our larger series (N=58), 15 healthy individuals and 10 SLAH patients without visual complications. Diffusion tractography was used to evaluate laser catheter penetration of the optic radiations. Using a complementary approach, we evaluated evidence for focal microstructural tissue damage within the optic radiations and lateral geniculate nucleus. Over-ablation and potential heat radiation were assessed by quantifying ablation and choroidal fissure CSF volumes as well as energy deposited during SLAH. SLAH treatment parameters did not distinguish VFD patients. Atypically high overlap between the laser catheter and optic radiations was found in 1 / 3 VFD patients, and was accompanied by focal reductions in fractional anisotropy where the catheter entered the lateral occipital white matter. Surprisingly, lateral geniculate tissue diffusivity was abnormal following, but also preceding, SLAH in patients who subsequently developed a VFD (all p ≤ 0.005). In our series, vision-related complications following SLAH, which appear to occur less frequently than following open temporal lobe surgery, were not directly explained by SLAH treatment parameters. Instead, our data suggest that variations in lateral geniculate structure may influence susceptibility to indirect heat injury from trans-occipital SLAH.

Citation

Voets, N. L., Alvarez, I., Qiu, D., Leatherday, C., Willie, J. T., Sotiropoulos, S., Gleichgerrcht, E., Bonilha, L., Pedersen, N., Kadom, N., Saindane, A., Gross, R. E., & Drane, D. L. (2019). Mechanisms and Risk Factors Contributing to Visual Field Deficits following Stereotactic Laser Amygdalohippocampotomy. Stereotactic and Functional Neurosurgery, 97(4), 255–265. https://doi.org/10.1159/000502701

• Journal Article Type: Article
• Acceptance Date: Aug 9, 2019
• Online Publication Date: Oct 16, 2019
• Publication Date: 2019-12
• Deposit Date: Oct 15, 2019
• Publicly Available Date: Oct 17, 2020
• Journal: Stereotactic and Functional Neurosurgery
• Print ISSN: 1011-6125
• Electronic ISSN: 1423-0372
• Publisher: Karger Publishers
• Peer Reviewed: Peer Reviewed
• Volume: 97
• Issue: 4
• Pages: 255–265
• DOI: https://doi.org/10.1159/000502701
• Keywords: Surgery; Clinical Neurology
• Public URL: https://nottingham-repository.worktribe.com/output/2413758
• Publisher URL: https://www.karger.com/Article/FullText/502701
• Contract Date: Oct 15, 2019