LMAP-18 ADAPTING LASER INTERSTITIAL THERMAL THERAPY (LITT) FOR TREATMENT OF INTRACRANIAL LESIONS IN CANINES

Malignant gliomas are devastating intracranial tumors with dismal prognoses that impose unique therapeutic challenges. Treatment options include surgical resection, radiation, and chemotherapy, but efficacy is limited and carries associated morbidity. Promise persists for newer modalities, such as immune-based platforms, but the blood-brain barrier (BBB) restricts intracranial therapeutic access, limiting success. Laser interstitial thermal therapy (LITT) is a minimally invasive surgical intervention permitting thermal ablation of brain tumors and other intracranial lesions. During LITT, a laser probe is stereotactically introduced through a small skull burr hole into the lesion. Continuous MRI is used to conduct real-time temperature monitoring via software-based calculation of cumulative thermal dosage zones. LITT is not only capable of ablating neoplastic tissue, but can also open the BBB in peritumoral regions, and thus may synergize with other emerging therapies. We adapted a commercially available LITT system (Monteris Medical) for use in dogs with intracranial lesions. Canine cadavers were used to optimize LITT procedures before employing this platform in live dogs. Our approach consists of 1. obtaining volumetric, T1-weighted, MRI studies to plan trajectories to intracranial targets, 2. fixing canine patients to a surgical bed and registering them for surface matching to a volume rendered image, 3. using an integrated instrument holder (Varioguide, Brainlab) to guide drilling of 4.5 mm skull burr holes for placement of self-tapping titanium “mini-bolts” (Monteris Medical), and 4. introducing the laser catheter probe through the mini-bolts for lesion ablation in the MRI suite. This method allows for rigid stereotaxy, successful neuronavigation, and a minimally invasive approach. We have successfully performed LITT on four canine patients with spontaneously occurring intracranial gliomas and plan to treat additional canine patients with intracranial lesions. Future studies will explore combination therapeutic platforms, including immunotherapy and gold nanoparticles to improve the efficiency and specificity of tumor ablation.