Analysis of Deep Brain Stimulation Lead Targeting in the Stimulation of Anterior Nucleus of the Thalamus for Epilepsy Clinical Trial

BACKGROUND: Deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) is an effective therapy for patients with drug-resistant focal epilepsy. Best practices for surgical targeting of the ANT can be refined as new information becomes available regarding effective stimulation sites. OBJECTIVE: To conduct a retrospective analysis of the relationship between outcomes (seizure reduction during year 1) and DBS lead locations in subjects from the SANTE pivotal trial (Stimulation of ANT for Epilepsy) based upon recent clinical findings. METHODS: Postoperative images from SANTE subjects (n = 101) were evaluated with respect to lead trajectory relative to defined anatomic landmarks. A qualitative scoring system was used to rate each lead placement for proximity to an identified target region above the junction of the mammillothalamic tract with the ANT. Each subject was assigned a bilateral lead placement score, and these scoreswere then compared to clinical outcomes. RESULTS: Approximately 70% of subjects had good bilateral lead placements based upon location with respect to the defined target. These subjects had a much higher probability of being a clinical responder (>50% seizure reduction) than those with scores reflecting suboptimal lead placements (43.5% vs 21.9%, P<.05). CONCLUSION: Consistent with experience from more established DBS indications, our findings and other recent reports suggest that there may be specific sites within the ANT that are associated with superior clinical outcomes. It will be important to continue to evaluate these relationships and the evolution of other clinical practices (eg, programming) to further optimize this therapy.

Automated summary

This study analyzed the relationship between DBS lead locations and clinical outcomes, finding that subjects with good bilateral lead placements based on defined targets were more likely to be clinical responders. Specific sites within the ANT may be associated with superior clinical outcomes, highlighting the importance of continuing to evaluate these relationships to optimize DBS therapy.