Stereoelectroencephalography-Guided Laser Ablations in Patients With Neocortical Pharmacoresistant Focal Epilepsy: Concept and Operative Technique

BACKGROUND

Laser ablation surgery has had encouraging results in the treatment of multiple intracranial diseases including primary and metastatic brain tumors, radiation necrosis, and epilepsy. The use of the stereoelectroencephalography (SEEG) method in combination with laser thermocoagulation therapy with the goal of modulating epileptic networks in patients with neocortical nonlesional phamacoresistant epilepsy has not been previously described.

OBJECTIVE

To describe the novel methodological and conceptual aspects related to SEEG-guided laser ablations in patients with magnetic resonance imaging (MRI)-negative pharmacoresistant neocortical focal epilepsy.

METHODS

Guided by previous SEEG intracranial data, a laser ablation probe was inserted by using a robotic guidance device in a 17-yr-old medically refractory epilepsy patient with difficult to localize seizures and nonlesional MRI. The laser applicator position was confirmed by MRI, targeting the left mesial rostral superior frontal gyrus. The ablation was performed under multiplanar digital imaging views and real-time thermal imaging and treatment estimates in each plane. A postablation MRI (contrasted T1 sequence) confirmed the ablation's location and size.

RESULTS

The entire procedure was achieved in approximately 100 min. The actual ablation was performed in less than 3 min. Approximately, additional 30 min preoperatively were used for positioning and robot registration. Precise placement of laser application (in comparison with preplanned trajectories) was achieved using the robotic guidance and confirmed by the intraoperative magnetic resonance images. No complications were reported. The patient has been seizure-free since surgery. The follow-up period is 20 mo. Two additional patients, treated with similar methodology, are also described.

CONCLUSION

The preliminary experience with the described method shows the feasibility of a unique combination of the SEEG methodology with laser thermocoagulation in patients with neocortical MRI-negative pharmacoresistant focal epilepsy.

Postoperative Outcomes of Magnetic Resonance Imaging (MRI)-Guided Laser Interstitial Thermal Therapy (LITT) in the Treatment of Drug-Resistant Epilepsy: A Meta-Analysis

BACKGROUND Drug-resistant epilepsy is a common neurological disease in adults and children. This study aimed to undertake a systematic review of the literature with meta-analysis of the data from published studies to assess the effectiveness of magnetic resonance imaging (MRI)-guided laser interstitial thermal therapy (LITT) in treatment-resistant epilepsy. MATERIAL AND METHODS The study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, MEDLINE, and EMBASE databases were systematically searched for indexed publications in the English language up to May 2018. Data on the prevalence, outcome using the Engel Epilepsy Surgery Outcome Scale (Class I to IV), and postoperative complications were analyzed with 95% confidence intervals (CIs). The Methodological Index for Non-Randomized Studies (MINORS) was used to assess the risk of bias in the included studies. RESULTS Sixteen published studies that included a total of 269 patients with treatment resistant epilepsy were identified. The prevalence of Engel Class I, II, III and IV were 61% (95% CI, 0.54-0.68; I²=14.5%; P=0.302), 12% (95% CI, 0.07-0.16; I²=86.8%; P=0.000), 16% (95% CI, 0.10-0.22; I²=3.0%; P=0.397), and 15% (95% CI, 0.08-0.22; I²=13.2%; P=0.330), respectively. The prevalence of postoperative complications was 24% (95% CI, 0.16-0.32; I2=0%; P=0.629). CONCLUSIONS Meta-analysis of data from 16 studies that included 269 patients with treatment-resistant epilepsy showed that MRI-guided LITT significantly reduced the frequency of seizures and reduced postoperative complications, supporting the safety and effectiveness of MRI-guided LITT in the treatment of drug-resistant epilepsy.

History and Technical Approaches and Considerations for Ablative Surgery for Epilepsy

The history of epilepsy surgery is generally noted to have begun in 1886 with Victor Horsley's first report of craniotomies for posttraumatic epilepsy. With increased understanding of brain function and development of electroencephalographic methods, nonlesional epilepsy began to be treated with resection in the 1950s. Methodological improvements and increased understanding of pathophysiology followed, and the advent of stereotaxy and ablative technology in the 1960s and 1970s heralded a new era of minimally invasive, targeted procedures for lesional and nonlesional epilepsy. Current techniques combine stereotactic methods, improved ablative technologies, and electroencephalographic methods for a multidisciplinary approach to the neurosurgical treatment of epilepsy.