MRI-Guided Laser Interstitial Thermal Therapy for Epilepsy Robert Y. North, MD, PhD a , Jeffrey S. Raskin, MD, MS b , Daniel J. Curry, MD b, * INTRODUCTION MRI-guided laser interstitial thermal therapy (LITT) represents a sophisticated application of modern stereotaxy, MRI, and laser technology. In brief, a laser is stereotactically placed into a target that is then thermally ablated while monitoring tissue temperatures with MRI thermography. Neurosur- gical applications of LITT have been described for both intracranial and spinal targets with treated pathologies having included primary and metasta- tic malignancies, radiation necrosis, benign le- sions, and functional targets in pain, movement disorders, and epilepsy. 1–10 Initially described by Curry and colleagues 10 in 2012, MRI-guided LITT for epilepsy (LITT-E) has become an established, minimally invasive alternative to traditional epi- lepsy surgery. LITT-E is particularly valuable in cases in which open surgery poses unacceptably high morbidity or patient preference precludes craniotomy. Here we present a focused review of technical details and application of LITT to both focal and generalized epilepsy. TECHNICAL CONSIDERATIONS AND GENERAL TECHNIQUE Preincision and Anesthesia All anesthesia medications, lines, and monitors must be MRI safe, and a standard patient MRI safety screening form should be completed. In cases in which ablation is the surgical goal without the need for intraoperative electrophysiology, the patient may undergo general anesthesia in which total intravenous anesthesia is not necessary. Chemical paralysis is used to prevent unwanted movement that can result in errant ablation. An arterial line is not necessary. Bladder decompres- sion is achieved using an indwelling catheter. A D.J. Curry has received consulting fees from Medtronic, and Monteris Medical. R.Y. North and J.S. Raskin declare no commercial or financial interests that could be construed as a potential conflict of interest. a Department of Neurosurgery, Baylor College of Medicine, 7200 Cambridge, Suite 9A, Houston, TX 77030, USA; b Division of Pediatric Neurosurgery, Department of Neurosurgery, Texas Children’s Hospital, Baylor Col- lege of Medicine, 6701 Fannin Street, Suite 1230, Houston, TX 77030, USA * Corresponding author. Division of Pediatric Neurosurgery, Department of Neurosurgery, Texas Children’s Hospital, Baylor College of Medicine, 6701 Fannin Street, Suite 1230, Houston, TX 77030. E-mail address: djcurry@bcm.edu KEYWORDS  Epilepsy  Laser ablation  LITT  MR-guided laser interstitial thermal therapy KEY POINTS  MRI-guided laser interstitial thermal therapy for epilepsy (LITT-E) primary application is focal epi- lepsies in both pediatric and adult patients. Application to generalized epilepsies remains limited, but is an area of active development.  LITT-E offers a minimally invasive procedure that may lessen neurologic and neuropsychological morbidity as well as interest patients who would otherwise refuse traditional surgical treatments.  Despite being a “minimally invasive” surgical approach, LITT-E requires considerable technological tools, logistical support, and technical expertise for safe stereotaxis and ablation. Neurosurg Clin N Am 28 (2017) 545–557 http://dx.doi.org/10.1016/j.nec.2017.06.001 1042-3680/17/Ó 2017 Elsevier Inc. All rights reserved. neurosurgery.theclinics.com