Magnetic Resonance-guided Laser Interstitial Therapy Research Articles

An Initial Experience of Completion Hemispherotomy via Magnetic Resonance-Guided Laser Interstitial Therapy

Introduction: In carefully selected patients with medically refractory epilepsy, disconnective hemispherotomy can result in significant seizure freedom; however, incomplete disconnection can result in ongoing seizures and poses a significant challenge. Completion hemispherotomy provides an opportunity to finish the disconnection. We describe the use of magnetic resonance-guided laser interstitial thermal ablation (MRgLITT) for completion hemispherotomy. Methods: Patients treated with completion hemispherotomy using MRgLITT at our institution were identified. Procedural and seizure outcomes were evaluated retrospectively. Results: Five patients (3 males) underwent six MRgLITT procedures (one child treated twice) for completion hemispherotomy at a median age of 6 years (range 1.8–12.9). Two children had hemimegalencephaly, two had Rasmussen encephalitis, and one had polymicrogyria. All five children had persistent seizures likely secondary to incomplete disconnection after their functional hemispherotomy. The mean time from open hemispherotomy to MRgLITT was 569.5 ± 272.4 days (median 424, range 342–1,095). One patient underwent stereoelectroencephalography before MRgLITT. The mean number of ablation targets was 2.3 ± 0.47 (median 2, range 2–3). The mean length of the procedure was 373 min ± 68.9 (median 374, range 246–475). Four of the five patients were afforded improvement in their neurocognitive functioning and speech performance after ablation, with mean daily seizure frequency at 1 year of 1.03 ± 1.98 (median 0, range 0–5). Two patients achieved Engel Class I outcomes at 1 year after ablation, one was Engel Class III, and two were Engel Class IV. The mean follow-up time was 646.8 ± 179.5 days (median 634, range 384–918). No MRgLITT-related complications occurred. Delayed retreatment (>1 year) occurred in three patients: one child underwent redo ablation and two underwent anatomic hemispherectomy. Conclusion: We have demonstrated the feasibility of a minimally invasive approach for completion hemispherotomy using MRgLITT. Delayed retreatment was needed in three patients; thus, further study of this technique with comparison to other surgical techniques is warranted.

LGG-21. MR-GUIDED LASER INTERSTITIAL THERMAL THERAPY FOR UNRESECTABLE AND SYMPTOMATIC PEDIATRIC LOW GRADE GLIOMA

BACKGROUNDPediatric low-grade gliomas (LGG) not amenable to resection, while often indolent, represent a significant source of cancer-related morbidity and an unmet therapeutic need. Standardly, these patients are treated with sequential lines of chemotherapy, while delaying as long as possible radiation. Magnetic resonance-guided laser interstitial therapy (LITT) is a minimally invasive procedure that utilizes real-time MR thermography to ablate brain lesions.METHODSA 15-year-old girl was diagnosed with a suprasellar, hypothalamic LGG, BRAF V600E mutation positive. The tumor was unresectable, and due to progressive vision loss and headaches, the patient underwent treatment. Despite sequential trials of thioguanine/procarbazine/lomustine/vincristine, carboplatin/vincristine, dabrafenib, and combination dabrafenib/trametinib, the patient continued to experience debilitating headaches, malnutrition, school absenteeism, and overall poor quality-of-life. Using real-time, sequential MRI-thermometry and the Neuroblate cooled directional laser catheter, the bulk of the enhancing tumor was heated to a killing temperature.RESULTSAt 1-year post LITT, the patient’s symptoms were dramatically improved, including greatly improved headaches, malnutrition, school absenteeism, and overall quality of life. LITT was generally well tolerated, though the patient had slight progressive left homonymous hemianopia, thought secondary to LITT impact on the optic tracts. The tumor progressively shrank over the year post-LITT to a peak of 42% volume reduction.CONCLUSIONWe report a case of a pediatric patient with an unresectable low grade glioma who underwent LITT with excellent clinical and radiographic effects. LITT should be considered for children with unresectable and morbid LGGs that fail to respond to more conventional therapies.

Laser interstitial thermal therapy for the treatment of epilepsy: evidence to date.

Medically intractable epilepsy is associated with increased morbidity and mortality. For those with focal epilepsy and correlated electrophysiological or radiographic features, open surgical resection can achieve high rates of seizure control, but can be associated with neurologic deficits and cognitive effects. Recent innovations have allowed for more minimally invasive methods of surgical seizure control such as magnetic resonance-guided laser interstitial therapy (MRgLITT). MRgLITT achieves the goal of ablating seizure foci while preserving neuropsycho-logical function and offering real-time feedback and monitoring of tissue ablation. This review summarizes the utilization of MRgLITT for mesial temporal lobe epilepsy and other seizure disorders. Overall, the efficacy of MRgLITT is comparable to that of open surgery and offers a less invasive approach in patients with significantly less morbidity.