OBJECTIVE Real-time, MRI-guided laser interstitial thermal therapy (MRgLITT) has been reported as a safe and effective technique for the treatment of epileptogenic foci in children and adults. After the recent approval of MRgLITT by the European Medicines Agency in April 2018, the authors began to use it for the treatment of hypothalamic hamartomas (HHs) in pediatric patients with the assistance of a robotic arm. In this study, the authors report their initial experience describing the surgical technique, accuracy of the robotic arm, safety, and efficacy. METHODS The laser fiber was placed with the assistance of the stereotactic robotic arm. The accuracy of the robotic arm for this procedure was calculated by comparing the intraoperative MRI to the preoperative plan. Common demographic and seizure characteristics of the patients, laser ablation details, complications, and short-term seizure outcomes were prospectively collected. RESULTS Sixteen procedures (11 first ablations and 5 reablations) were performed in 11 patients between 15 months and 17 years of age (mean age 6.4 years) with drug-resistant epilepsy related to HHs. The mean target point localization error was 1.69 mm. No laser fiber needed to be repositioned. The mean laser power used per procedure was 4.29 W. The trajectory of the laser fiber was accidentally ablated in 2 patients, provoking transient hemiparesis in one of these patients. One patient experienced postoperative somnolence and syndrome of inappropriate antidiuretic hormone secretion, and 2 patients had transient oculomotor (cranial nerve III) palsy. Fifty-four percent of the patients were seizure free after the first ablation (mean follow-up 22 months, range 15–33 months). All 5 patients who experienced an epilepsy relapse underwent a second treatment, and 4 remain seizure free at least 5 months after reablation. CONCLUSIONS In the authors’ experience, the robotic arm was sufficiently accurate for laser fiber insertion, even in very young patients. MRgLITT appears to be an effective treatment for selected cases of HH. MRgLITT for HH is a minimally invasive procedure with appealing safety features, as it allows delivery of energy precisely under real-time MRI control. Nonetheless, complications may occur, especially in voluminous HHs. The amount of delivered energy and the catheter cooling system must be closely monitored during the procedure. A larger sample size and longer follow-up duration are needed to judge the efficacy and safety of MRgLITT for HH more rigorously. This initial experience was very promising.

OBJECTIVE Since 2007, the authors have performed 34 hemispherotomies and 17 posterior quadrant disconnections (temporoparietooccipital [TPO] disconnections) for refractory epilepsy at Sant Joan de Déu Barcelona Children’s Hospital. Incomplete disconnection is the main cause of surgical failure in disconnective surgery, and reoperation is the treatment of choice. In this study, 6 patients previously treated with hemispherotomy required reoperation through open surgery. After the authors’ initial experience with real-time MRI-guided laser interstitial thermal therapy (MRIgLITT) for hypothalamic hamartomas, they decided to use this technique instead of open surgery to complete disconnective surgeries. The objective was to report the feasibility, safety, and efficacy of MRIgLITT to complete hemispherotomies and TPO disconnections for refractory epilepsy in pediatric patients. METHODS Eight procedures were performed on 6 patients with drug-resistant epilepsy. Patient ages ranged between 4 and 18 years (mean 10 ± 4.4 years). The patients had previously undergone hemispherotomy (4 patients) and TPO disconnection (2 patients) at the hospital. The Visualase system assisted by a Neuromate robotic arm was used. The ablation trajectory was planned along the residual connection. The demographic and epilepsy characteristics of the patients, precision of the robot, details of the laser ablation, complications, and results were prospectively collected. RESULTS Four patients underwent hemispherotomy and 2 underwent TPO disconnection. Two patients, including 1 who underwent hemispherotomy and 1 who underwent TPO disconnection, received a second laser ablation because of persistent seizures and connections after the first treatment. The average precision of the system (target point localization error) was 1.7 ± 1.4 mm. The average power used was 6.58 ± 1.53 J. No complications were noted. Currently, 5 of the 6 patients are seizure free (Engel class I) after a mean follow-up of 20.2 ± 5.6 months. CONCLUSIONS According to this preliminary experience, laser ablation is a safe method for complete disconnective surgeries and allowed epilepsy control in 5 of the 6 patients treated. A larger sample size and longer follow-up periods are necessary to better assess the efficacy of MRIgLITT to complete hemispherotomy and TPO disconnection, but the initial results are encouraging.

ObjectiveIn this study, we present our experience with 1.5-T high-field intraoperative magnetic resonance imaging (ioMRI) for different neuro-oncological procedures in a pediatric population, and we discuss the safety, utility, and challenges of this intraoperative imaging technology.MethodsA pediatric consecutive-case series of neuro-oncological surgeries performed between February 2020 and May 2022 was analyzed from a prospective ioMRI registry. Patients were divided into four groups according to the surgical procedure: intracranial tumors (group 1), intraspinal tumors (group 2), stereotactic biopsy for unresectable tumors (group 3), and catheter placement for cystic tumors (group 4). The goal of surgery, the volume of residual tumor, preoperative and discharge neurological status, and postoperative complications related to ioMRI were evaluated.ResultsA total of 146 procedures with ioMRI were performed during this period. Of these, 62 were oncology surgeries: 45 in group 1, two in group 2, 10 in group 3, and five in group 4. The mean age of our patients was 8.91 years, with the youngest being 12 months. ioMRI identified residual tumors and prompted further resection in 14% of the cases. The mean time for intraoperative image processing was 54 ± 6 min. There were no intra- or postoperative security incidents related to the use of ioMRI. The reoperation rate in the early postoperative period was 0%.ConclusionioMRI in pediatric neuro-oncology surgery is a safe and reliable tool. Its routine use maximized the extent of tumor resection and did not result in increased neurological deficits or complications in our series. The main limitations included the need for strict safety protocols in a highly complex surgical environment as well as the inherent limitations on certain patient positions with available MR-compatible headrests.