Optic Radiation Tractography and Visual Field Deficits in Laser Interstitial Thermal Therapy for Amygdalohippocampectomy in Patients with Mesial Temporal Lobe Epilepsy.
Laser interstitial thermal therapy (LITT) has become an alternative to open-resective surgery for refractory mesial temporal lobe epilepsy (MTLE). Occurrence of visual field defects (VFDs) following open surgery for MTLE is reported at 52-100%. We examined the rate of VFDs following LITT for amygdalohippocampectomy (AHE) and correlated the occurrence of VFDs with damage to the optic radiations, assessed by diffusion tensor tractography (DTI).



We performed a retrospective analysis of 5 patients who underwent LITT-AHE for medically refractory MTLE. We examined the association between VFDs and optic radiation damage by correlating postprocedural visual field testing with qualitative assessment of optic radiation fiber tracts.



Postoperative assessments showed that 4 patients had normal visual field testing, and 1 had a right superior quadrantanopsia (20%). We performed 3-dimensional reconstruction of the optic radiation, laser probe trajectory, and ablation volume. Damage to Meyer's loop was determined consistent with the VFD.



Short-term follow-up in our series suggests that laser ablation AHE may be associated with a lower rate of VFD than has been reported for open AHE. Our results suggest that incorporating optic radiation mapping through DTI may preoperatively help to minimize the risk of VFD following laser ablation AHE.
Department of Neurosurgery, University of Colorado, Denver, CO, USA.
Dali
D
Yin
John A
JA
Thompson
Cornelia
C
Drees
Steven G
SG
Ojemann
Lidia
L
Nagae
Victoria S
VS
Pelak
Aviva
A
Abosch
D000328:Adult; D000368:Aged; D000679:Amygdala / Q000000981:diagnostic imaging / Q000601:surgery*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D004833:Epilepsy, Temporal Lobe / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006624:Hippocampus / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D053685:Laser Therapy / Q000009:adverse effects / Q000639:trends*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014786:Vision Disorders / Q000000981:diagnostic imaging / Q000209:etiology*; D014794:Visual Fields / Q000502:physiology; D014795:Visual Pathways / Q000000981:diagnostic imaging
Amygdalohippocampectomy; Diffusion tensor tractography; Laser ablation; Mesial temporal lobe epilepsy; Tractography; Visual field defects