Real-Time Magnetic Resonance-Guided Stereotactic Laser Amygdalohippocampotomy for Mesial Temporal Lobe Epilepsy

Abstract

Background Open surgery effectively treats mesial temporal lobe epilepsy (MTLE), but carries risks of neurocognitive deficits, which may be reduced with minimally invasive alternatives. Objective To describe technical and clinical outcomes of stereotactic laser amygdalohippocampotomy (SLAH) with real-time magnetic resonance thermal imaging (MRTI) guidance. Methods Under general anesthesia and utilizing standard stereotactic methods, 13 adult patients with intractable MTLE (with and without mesial temporal sclerosis, MTS) prospectively underwent insertion of a saline-cooled fiber-optic laser applicator into amygdalohippocampal structures from an occipital trajectory. Computer-controlled laser ablation was performed during continuous MRTI followed by confirmatory contrast-enhanced anatomic imaging and volumetric reconstruction. Clinical outcomes were determined from seizure diaries. Results A mean 60% volume of the amygdalohippocampal complex was ablated in 13 patients (9 with MTS) undergoing 15 procedures. Median hospitalization was one day. With follow-up ranging from 5-26 (median 14) months, 77% (10/13) of patients achieved meaningful seizure reduction, of which 54% (7/13) were free of disabling seizures. Of patients with preoperative MTS, 67% (6/9) achieved seizure freedom. All recurrences were observed by<6 months. Variances in ablation volume and length did not account for individual clinical outcomes. Whereas no complications of laser therapy itself were observed, one significant complication, a visual field defect, resulted from deviated insertion of a stereotactic aligning rod, which was corrected prior to ablation. Conclusion Real-time MR-guided SLAH is a technically novel, safe, and effective alternative to open surgery. Further evaluation with larger cohorts over time is warranted.

Advancements in Stereotactic Epilepsy Surgery: Stereo-EEG, Laser Interstitial Thermotherapy, and Responsive Neurostimulation

“…In one series of 13 adult patients with mesial temporal lobe epilepsy (MTLE) with or without MTS, LITT resulted in approximately 60% destruction of the amygdalohippocampal volume and 54% seizure freedom at a mean follow-up of 14 months. 15 Our own institutional experience has demonstrated similar results, with 53% seizure freedom at 6 months, 36.4% at 1 year, and 60% at 2-year follow-up (loss to follow-up in a small patient sample resulting in the variable results within the study period). 18 Results 17 Intra-operatively, a manual arc-ring system is used with the CRW frame to guide placement of the anchor bolt, instead of the robotic system, given the time involved setting up the robot is not justified for a single trajectory.…”

“…Thermal ablation for focal epilepsy was initially described using radiofrequency (RF) thermocoagulation probes. In our experience to date at Jefferson, 27 patients have undergone implantation of a total of 342 electodes (mean 12.7, range [5][6][7][8][9][10][11][12][13][14][15][16][17]. No patient experienced permanent morbidity or mortality related to the SEEG…”

Magnetic Resonance Imaging-Guided Laser Interstitial Thermal Therapy for Treatment of Drug-Resistant Epilepsy

“…In 2012, Curry and his team at Texas Children's Hospital [12] first reported the feasibility and efficacy of MRI-guided LiTT in ablating epileptic lesions in 5 pediatric patients. Since then, laser has been used to ablate a variety of epileptogenic lesions, including periventricular nodular heterotopia [13], tuberous sclerosis [14], cortical dysplasia [12,14], insular encephalomalacia [15], hypothalamic hamartomas (HH), and MTLE [7,12,16,17]. Although the literature on outcomes is limited to a handful reports, MRguided LiTT is a promising treatment alternative to open resections in patients with MTLE and HH.…”

“…Seizure freedom after LiTT in MTLE at 1 to 2 years ranges from 40% to 60%, with higher rates of seizure freedom seen in patients with MTS on MRI [7,17]. In 2014, Willie et al [17] published the results of LiTT therapy in 13 patients who underwent stereotactic laser amygdalohippocampotomy (SLAH) for medically intractable MTLE.…”

Magnetic resonance imaging–guided laser interstitial thermal therapy for previously treated hypothalamic hamartomas

“…Realtime MR thermometry depicts tissue heating and suggests spatial localization of coagulation zones as the treatment is performed, allowing for tailored therapy with adaptations to results during one treatment session. Early reports of MRg-LITT have indicated preliminary safety and efficacy in the treatment of recurrent primary and metastatic tumors, 2,8,9,19,23 mesial temporal lobe epilepsy, 27 and other epileptic foci 3,8 including HHs and periventricular nodular heterotopias. 5,26 Furthermore, MRg-LITT may offer the possibility of another less invasive option for epilepsy surgery and in this case will significantly limit approachrelated morbidity.…”