Laser-induced thermal therapy uses thermal energy to induce cell death by damaging DNA and causing protein denaturation. The current therapy is performed with simultaneous MRI stereotactic guidance and real-time feedback from the ablated lesion. 1) 2).
It is considered less invasive than microsurgery. Main advantage is a shorter postoperative recovery period. The technique has been used for lesional and nonlesional epilepsy. Preliminary seizure control ≈ 60–70%. No long-term data is yet available.
Magnetic resonance-guided, Laser interstitial thermotherapy (LITT) is a real-time magnetic resonance thermometry - guided, minimally invasive procedure that uses a laser to produce a precise and minimally invasive heat injury to target tissue.
To deliver this energy in a minimally invasive fashion, a small diameter fiber optic applicator is inserted into the lesion through a keyhole stereotactic procedure. The thermal energy induces damage to intracellular DNA and DNA-binding structures, ultimately leading to cell death. The ablation procedure is supervised by real-time MRI thermal mapping and confirmed by immediate post-ablation T1 or FLAIR MRI images.
Magnetic resonance (MR)-guided stereotactic laser ablation is a minimally invasive alternative that uses small applicators amenable to stereotactic delivery. Heating is dependent on source wavelength such that a source laser can be chosen to produce rapid and localized heating of tissue with sharp boundaries at relatively low powers 3).
Because optical fibers and laser energy are MR imaging (MRI) compatible, simultaneous MR thermal imaging (MRTI), with accuracy on the order of ±0.2°C in a number of tissue types enables real-time feedback control of laser output and tissue ablation. MR-guided stereotactic laser ablation has been safely used for ablation of intracranial lesions including tumors and certain epileptogenic foci in children 4) 5) 6) 7) 8) 9) 10).
Neurosurgical laser ablation is a relatively new but rapidly growing application of stereotactic neurosurgery that allows neurosurgeons to treat many previously untreatable conditions with the added benefit of shorter hospitalizations and recovery times. The vast majority of these procedures, however, are performed using a multisite workflow pattern involving transport of the patient between the operating room (OR), the computed tomography (CT) suite, and the magnetic resonance imaging (MRI) suite, often necessitating patient transfer through public pathways and requiring multiple trips if laser fiber placement is not accurate. There are significant risks posed to the patient with this practice and no existing guidelines addressing it 11).
Laser ablation is an emerging, minimally invasive treatment for selected children with intractable focal epilepsy with improved procedural morbidity. Data for children lag similar studies in adults, but the hope is for near-equivalent seizure-control rates and improved neuropsychological outcome when compared with standard open surgical resection. The approach seems particularly beneficial when dealing with deep, focal lesions, such as hypothalamic hamartomas or hippocampal sclerosis 12).
The NeuroBlate System (formerly known as the AutoLITT® System) applies focused laser energy to ablate brain tumors from the inside, with little or no effect on surrounding healthy tissue. NeuroBlate provides clinicians a new neurosurgical tool that offers real-time control and visualization of the therapy during laser ablation treatment. The NeuroBlate procedure is currently one of the only laser ablation neurosurgical procedures done in an active MRI magnet.
Used also in the treatment of pain.