Background Open surgery effectively treats mesial temporal lobe epilepsy (MTLE), but carries risks of neurocognitive deficits, which may be reduced with minimally invasive alternatives. Objective To describe technical and clinical outcomes of stereotactic laser amygdalohippocampotomy (SLAH) with real-time magnetic resonance thermal imaging (MRTI) guidance. Methods Under general anesthesia and utilizing standard stereotactic methods, 13 adult patients with intractable MTLE (with and without mesial temporal sclerosis, MTS) prospectively underwent insertion of a saline-cooled fiber-optic laser applicator into amygdalohippocampal structures from an occipital trajectory. Computer-controlled laser ablation was performed during continuous MRTI followed by confirmatory contrast-enhanced anatomic imaging and volumetric reconstruction. Clinical outcomes were determined from seizure diaries. Results A mean 60% volume of the amygdalohippocampal complex was ablated in 13 patients (9 with MTS) undergoing 15 procedures. Median hospitalization was one day. With follow-up ranging from 5-26 (median 14) months, 77% (10/13) of patients achieved meaningful seizure reduction, of which 54% (7/13) were free of disabling seizures. Of patients with preoperative MTS, 67% (6/9) achieved seizure freedom. All recurrences were observed by<6 months. Variances in ablation volume and length did not account for individual clinical outcomes. Whereas no complications of laser therapy itself were observed, one significant complication, a visual field defect, resulted from deviated insertion of a stereotactic aligning rod, which was corrected prior to ablation. Conclusion Real-time MR-guided SLAH is a technically novel, safe, and effective alternative to open surgery. Further evaluation with larger cohorts over time is warranted.

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Laser-induced thermal therapy is an intuitive procedure for treating difficult intracranial neoplasms. As with any other procedure, patient selection and lesion selection are important factors in determining outcome.

In this ongoing trial, a total of four patients have had six metastatic tumors treated with laser thermal ablations. Magnetic resonance-guided laser-induced thermal therapy appears to provide a new, efficient treatment for recurrent focal metastatic brain disease. This therapy is a prelude to the future development of closed-head interventional MRI techniques in neurosurgery.

Real-time magnetic resonance (MR) guidance of laser-induced thermal therapy (LITT) offers a high level of control. This tool therefore enables a minimally invasive option for destruction and treatment of resistant focal metastatic intracranial tumors. MR-guided LITT appears to provide a safe and potentially effective treatment for recurrent focal metastatic brain disease. A larger phase II and III series would be of interest to quantify potential median survival advantage.

The computer-controlled thermal therapy system was effective at regulating heating, eliminating carbonization and vaporization, and protecting fiberoptic applicators. MRTI estimation of thermal dose accurately predicted achieved thermal necrosis.

Focal tumor control was performed safely using minimally invasive LITT with real-time MRTI control. LITT could be considered as salvage therapy for high-grade recurrent gliomas if a 1-day treatment is considered useful for a few weeks gain in survival. Larger experience will be required to define indications for such infiltrative disease and accurately determine a potentially significant survival gain in good neurological condition associated with this 1-day procedure.

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