Clinically Significant Visual Deficits after Laser Interstitial Thermal Therapy for Mesiotemporal Epilepsy

Area of Science:

• Neurosurgery
• Epilepsy Treatment
• Medical Imaging

Background:

• Laser interstitial thermal therapy (LITT) is a popular minimally invasive surgery for mesiotemporal epilepsy (mTLE).
• Visual deficits are common neurological complications of LITT, similar to open epilepsy surgery.
• A detailed analysis of LITT-induced visual injuries is currently lacking.

Purpose of the Study:

• To investigate the visual deficits following LITT for mTLE.
• To determine the underlying causes and mechanisms of these visual deficits.

Main Methods:

• Surveyed five epilepsy centers for patients reporting visual deficits post-LITT.
• Co-registered pre-, intra-, and postoperative MRIs with an atlas to assess thermal injury to visual pathways.
• Used logistic regression to compare patients with deficits to a control cohort based on demographics, anatomy, and surgical variables.

Main Results:

• 6.7% of 90 mTLE patients reported visual deficits (hemianopsia, quadrantanopsia, CN IV palsy).
• Deficits correlated with posterior ablation sites and increased laser energy delivery.
• Specific deficits linked to lateral geniculate nucleus insult, Meyer's loop injury, or tentorial edge extension.

Conclusions:

• LITT for epilepsy can cause diverse visual deficits with distinct causes.
• Understanding these injury mechanisms is crucial for reducing their incidence.
• Tailoring ablation procedures and identifying at-risk patients/trajectories can minimize visual complications.