Safety and effectiveness of stereotactic laser ablation for epileptogenic cerebral cavernous malformations

Abstract

Objective: Magnetic resonance (MR) thermography-guided laser interstitial thermal therapy, or stereotactic laser ablation (SLA), is a minimally invasive alternative to open surgery for focal epilepsy caused by cerebral cavernous malformations (CCMs). We examined the safety and effectiveness of SLA of epileptogenic CCMs.

Methods: We retrospectively analyzed 19 consecutive patients who presented with focal seizures associated with a CCM. Each patient underwent SLA of the CCM and adjacent cortex followed by standard clinical and imaging follow-up.

Results: All but one patient had chronic medically refractory epilepsy (median duration 8 years, range 0.5-52 years). Lesions were located in the temporal (13), frontal (five), and parietal (one) lobes. CCMs induced magnetic susceptibility artifacts during thermometry, but perilesional cortex was easily visualized. Fourteen of 17 patients (82%) with >12 months of follow-up achieved Engel class I outcomes, of which 10 (59%) were Engel class IA. Two patients who were not seizure-free from SLA alone became so following intracranial electrode-guided open resection. Delayed postsurgical imaging validated CCM involution (median 83% volume reduction) and ablation of surrounding cortex. Histopathologic examination of one previously ablated CCM following open surgery confirmed obliteration. SLA caused no detectable hemorrhages. Two symptomatic neurologic deficits (visual and motor) were predictable, and neither was permanently disabling.

Significance: In a consecutive retrospective series, MR thermography-guided SLA was an effective alternative to open surgery for epileptogenic CCM. The approach was free of hemorrhagic complications, and clinically significant neurologic deficits were predictable. SLA presents no barrier to subsequent open surgery when needed.

Keywords: cerebral cavernous malformation; laser interstitial thermal therapy; lesional epilepsy; magnetic resonance thermometry; seizure; stereotactic laser ablation.