Thalamic stereoelectroencephalography: safety, accuracy, and thalamocortical connectivity

Area of Science:

• Neurosurgery
• Epileptology
• Neuroscience

Background:

• Growing interest in thalamic sampling for epilepsy stereoelectroencephalography (sEEG).
• Limited data exists on thalamic sEEG safety, accuracy, and nucleus-specific connectomics (anterior, centromedian, pulvinar).
• Comparison of thalamic sEEG to epilepsy deep brain stimulation (DBS) is needed.

Purpose of the Study:

• To report the safety, accuracy, and connectivity of thalamic sEEG.
• To compare thalamic sEEG results with epilepsy DBS outcomes.
• To analyze thalamocortical connectivity patterns for specific thalamic nuclei (ANT, CM, PUL).

Main Methods:

• Single-center study (2018-2024) of epilepsy patients with thalamic sEEG or DBS implants.
• Utilized frameless stereotactic or robotic systems for sEEG (0.8mm lead) and rigid frame for DBS (1.81mm cannula).
• Assessed post-surgical complications, targeting accuracy (proximity to Morel atlas nuclei), and thalamocortical connectivity via structural connectome analysis.

Main Results:

• 160 sEEG and 188 DBS leads implanted in 109 and 83 patients, respectively.
• One sEEG patient (0.9%) had symptomatic hemorrhage; 8 DBS patients had transient complications.
• Excellent targeting accuracy for both (sEEG median 0.30mm, DBS 0.23mm), with sEEG showing more outliers (4% vs. 0%).
• Highly consistent thalamocortical connectivity patterns between sEEG and DBS cohorts (Spearman's ρ=0.86-0.98).
• Distinct connectivity profiles identified for ANT, CM, and PUL nuclei.

Conclusions:

• Thalamic sEEG exhibits a favorable safety profile and excellent targeting accuracy compared to DBS.
• The smaller sEEG lead diameter likely contributes to its safety.
• Consistent and distinct thalamocortical connectivity profiles support individualized targeting strategies using thalamic sEEG.