Introduction: MRI-Guided Laser Interstitial Thermal Therapy (MRgLITT) is an emerging minimally invasive procedure for the treatment of deep intracranial lesions. Insular tumors are challenging to treatment without damaging important surrounding structures. The option of a minimally invasive procedure is appealing, but the precise knowledge of the neural structures that are at risk along the trajectory and during the ablation is essential to reduce associated complications. We aimed to describe the relevant anatomy of the LITT trajectory to the insular region by using sectional anatomy and fiber dissection technique.
Methods: Three silicone injected cadaveric heads were used to implant laser catheters bilaterally to the insular region by using a frameless stereotactic technique. Sections were cut in both in oblique axial plane parallel to the trajectory and in the coronal plane. White matter fiber dissections were used to establish the tracts related to the laser trajectory. MR tractography was used to demonstrate the fibers surrounding the catheter path.
Results: Supraorbital regions were selected as entry points for each procedure. After crossing the frontal bone, the track intersected the inferior frontal lobe (figure 1). The catheter was illustrated reaching the insular region medial to the inferior fronto-occipital fasciculus and insular cortex, and superior to the uncinate fasciculus. Uncinate fasciculus, extreme capsule, claustrum, external capsule and the putamen were traversed, preserving the major vascular structures (figure 2).
Conclusions: Independent of the insular area treated, an understanding of the neuroanatomy related to the laser trajectory is essential to improve the ability to perform LITT of this challenging region. The current study is the first to examine the anatomy of the laser trajectory into the insular region and will serve as the basis for future studies.
Patient Care: The knowledge of the insular neuroanatomy and the structures transversed from supraorbitary region to the central core is essential to improve patient care when performing MRI-Guided Laser Interstitial Thermal Therapy in this region.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of the neuroanatomy of the trajectory to a selected target in the insula. 2) Apply alternatives to prevent complications in the LITT targeting insular lesions. 3) Identify effective target strategies for the treatment of insular tumors.