Laser interstitial thermal therapy in pediatric neurosurgery: A prospective nation-wide study on indications, safety and early outcomes

Laser interstitial thermal therapy in pediatric neurosurgery: A prospective nation-wide study on indications, safety and early outcomes | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Laser interstitial thermal therapy in pediatric neurosurgery: A prospective nation-wide study on indications, safety and early outcomes Silas Haahr Nielsen, Jon Foss-Skiftesvik, Torstein Melling, Astrid Sehested, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8831264/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 9 You are reading this latest preprint version Abstract Purpose To evaluate indications, safety, and early outcomes of MRI-guided laser interstitial thermal therapy (LITT) in a nationwide prospective pediatric cohort and to assess the feasibility of same-session stereotactic biopsy. Methods All consecutive pediatric patients (≤ 18 years) undergoing LITT at the Danish national referral center between June 2021 and October 2025 were prospectively enrolled. Demographic, clinical, radiological, and surgical variables were recorded. Safety outcomes included intraoperative complications, neurological deficits, length of stay, and 30-day readmission. Seizure outcomes were assessed by Engel classification, and tumor response by follow-up MRI. Results A total of 27 children (mean age 12 years, range 2–18) underwent LITT, including 18 treated for drug-resistant epilepsy and 9 for tumor indications. Same-session stereotactic biopsy was performed in 10 patients without biopsy-related complications or interference with ablation. No intraoperative complications occurred. Transient neurological deficits were observed in 8 patients and persistent deficits in 3. Hospital stay was ≤ 2 days in 23 patients, and no 30-day readmissions occurred. Seizure freedom (Engel class I) was achieved in 71%, 63%, and 57% at 6, 12, and 24 months, respectively. In tumor patients (median follow-up 15 months), MRI showed tumor control in 4 of 5 cases. Conclusion In this nationwide prospective cohort of 27 consecutively treated children, LITT was associated with a favorable safety profile for both epilepsy and tumor indications. Same-session stereotactic biopsy was feasible and safe, supporting LITT as a minimally invasive option in selected pediatric patients. laser interstitial thermal therapy stereotactic laser ablation pediatric neurosurgery epilepsy surgery pediatric brain tumors minimally invasive Figures Figure 1 Introduction MRI-guided laser interstitial thermal therapy (LITT) is a minimally invasive neurosurgical technique that enables targeted thermal ablation of intracranial lesions. By delivering controlled near-infrared energy through a stereotactically placed laser fiber with real-time temperature monitoring, LITT achieves precise tissue ablation while minimizing injury to surrounding brain structures. The technique has emerged as a promising alternative to conventional open surgery for lesions located in deep or eloquent regions where resection carries substantial risk. Since its clinical introduction in 2018 in Europe, LITT has been increasingly adopted for a range of neurological conditions [ 10 ]. In adults, evidence in neuro-oncology consists of retrospective and prospective case series and supports the safety and efficacy of this technique for newly diagnosed and recurrent gliomas, as well as previously irradiated or deep-seated secondary brain tumors [ 9 , 10 ]. For epilepsy, LITT has shown seizure control rates comparable to open resection in matched cohorts, and with the advantages of shorter hospital stays, fewer complications, and fewer permanent neurological deficits [ 15 ]. In pediatric neurosurgery, evidence for the use of LITT remains more limited. A recent systematic review and pooled analysis of 354 pediatric patients with drug-resistant epilepsy reported seizure freedom (Engel class I) in 57% at a mean follow-up of 16 months, with the best outcomes observed in patients with lesional epilepsy and hypothalamic hamartomas [ 23 ]. For pediatric brain tumors, conventional treatment continues to rely on open resection, which carries a risk of morbidity due to surgical access in deep-seated or midline lesions. The minimally invasive nature of LITT offers the potential to address selected tumors while reducing morbidity and facilitating early postoperative recovery and adjuvant therapy. Pediatric case series have demonstrated the feasibility of LITT for diverse pathologies, including low-grade gliomas (LGGs), ganglioglioma, dysembryoplastic neuroepithelial tumors (DNETs), subependymal giant cell astrocytoma (SEGAs), and ependymomas, with encouraging safety profiles [ 13 , 24 ]. Nonetheless, most available data derive from single-center, retrospective cohorts, underscoring the need for systematically collected, prospective evidence [ 13 ]. In pediatric tumor neurosurgery, obtaining a tissue diagnosis with contemporary molecular profiling is central to treatment planning, particularly for low-grade gliomas in which targeted therapies are increasingly used [ 18 , 19 ]. Several pediatric LITT series have reported performing stereotactic biopsy in the same session as ablation, demonstrating technical feasibility [ 1 , 2 , 13 , 14 , 20 ]. However, these data are limited to small or retrospective experiences, and no prospective studies have, to our knowledge, systematically evaluated the safety of combined biopsy and LITT in children. To address these gaps, we conducted a four-year prospective cohort study of consecutively treated pediatric patients undergoing LITT at a national referral center in Denmark. The study aimed to evaluate operative safety, length of stay, and early clinical and radiographic outcomes across epilepsy and tumor indications, providing one of the first systematically collected prospective datasets in the pediatric LITT field. Methods Study design and inclusion This prospective cohort study was approved by the National Danish Research Ethics Committee (Project ID: H-21047703). All pediatric patients (≤ 18 years) who underwent LITT at Rigshospitalet between June 1, 2021, and October 31, 2025, were consecutively enrolled. Patients treated with LITT for epilepsy indications were evaluated and followed according to the Danish National Epilepsy Surgery Program, including a standardized preoperative workup and a 2-year postoperative follow-up. The indication for LITT in epilepsy cases was established at a multidisciplinary epilepsy surgery conference. Indications for LITT in oncological cases were determined at a national multidisciplinary tumor board. Data collection Demographic, clinical, radiological, surgical, and outcome data were prospectively obtained from electronic medical records and imaging archives. Recorded variables included sex, age at treatment, indication (drug-resistant epilepsy or tumor growth), and lesion location. Surgical parameters comprised stereotactic technique, biopsy in same session as LITT, awake setup, number of laser fibers, diffusion tip length (3 or 10 mm), number of retractions, ablation volume including the contrast enhancing-rim (volume was calculated using the ellipsoid approximation: V = (π/6) × length × height × width), and operative time (defined as the interval from stereotactic setup to skin closure following catheter removal). Postoperative variables included steroid and opioid use, length of stay, postoperative disposition, and 30-day readmission. Complications were categorized as none, transient neurological deficit (resolved within 30 days), or persistent deficit (present beyond 3 months). Hypothalamic hamartoma–specific sequelae (weight gain, appetite change, memory disturbance, or endocrinologic abnormalities) were also recorded. Follow-up data included clinical and radiographic outcomes and length of follow-up. For epilepsy patients, etiology, age at seizure onset, latency to LITT, number of antiseizure medications (ASMs) at treatment, prior interventions, and Engel classification at 6, 12, and 24 months were collected. For tumor patients, histology, recurrence, and radiographic response at last follow-up were documented. Time to last follow-up, survival status, and date of last contact were noted for all patients. Surgical technique All procedures were performed using the Visualase system (Medtronic, Minneapolis, MN, USA). Laser catheter placement and, when indicated, biopsy were guided by either a frame-based stereotactic system (Cosman–Robert–Wells, Integra LifeSciences, Plainsboro, NJ, USA) or an MRI-guided SmartFrame Array (ClearPoint Neuro, Irvine, CA, USA). The SmartFrame system was preferentially used for small, deep-seated targets requiring high stereotactic accuracy, which in this case series included hypothalamic hamartomas. Image registration and trajectory verification were performed using an intraoperative CT scanner (AIRO, Brainlab AG, Munich, Germany). Real-time MR thermography was conducted on a 1.5-T intraoperative MRI system (GE Healthcare, Chicago, IL, USA). Statistical analysis Continuous variables are reported as mean (range) or median (range), as appropriate; categorical variables are presented as counts and percentages. Results Cohort characteristics A total of 27 pediatric patients (mean age 12 years; range, 2–18 years) underwent LITT between June 2021 and October 2025 (Table 1 ). The cohort comprised 14 females (52%) and 13 males (48%). The primary indication was drug-resistant epilepsy in 18 patients (67%) and tumor growth in 9 patients (33%). Lesion locations included the temporal lobe (n = 7), hypothalamic region (n = 6), corpus callosum (n = 3), parietal lobe (n = 2), frontal lobe (n = 2), intraventricular region (n = 2), and cerebellum (n = 2), as well as the occipital, thalamic, and insular regions (n = 1). Procedural characteristics A frame-based stereotactic system was used in 23 cases (85%), while the MRI-guided SmartFrame was applied in 4 cases (15%) [ 17 ], the latter all targeting hypothalamic hamartomas. Same-session biopsy was performed in 10 patients, including 7 with tumor indications (excluding subependymal giant cell astrocytomes (SEGAs)) and 3 epilepsy patients in whom a low-grade glioma or glioneuronal tumor was suspected. There were no biopsy related complications, and the combined approach did not compromise the subsequent ablation, defined as no bleeding or air artifact interference. One patient underwent awake LITT with intraoperative language testing; the ablation was tailored to reduce the risk of permanent postoperative aphasia [ 12 ]. The procedure included preoperative constrained spherical deconvolution (CSD) tractography performed with Quicktome software (Omniscient Neurotechnology) and intraoperative language assessment after controlled temperature increase to approximately 46°C for less than 30 seconds. A single laser fiber was used in 25 patients (93%), two fibers in 1 patient (4%), and three fibers in 1 patient (4%). The diffusion-tip length was 10 mm in 26 cases and 3 mm in 1 case. The median number of retractions was 1 (range, 0–5). The mean ablation volume was 2.5 cm³ (range, 0.2–11 cm³), and the mean ablation diameter was 1.3 cm (range, 0.7–1.9 cm). The mean operative time was 171 minutes (range, 104–335 minutes). When using the MRI SmartFrame, the mean operative time was 270 minutes, compared with 153 minutes when using the frame-based stereotactic system. Intraoperative complications and postoperative course No intraoperative complications occurred, and there were no cases of catheter repositioning, hemorrhage, or anesthesiologic complications. Postoperatively, 19 patients (70%) had no new neurological deficits. Transient neurological deficits were observed in 8 patients (30%) and included motor deficits (n = 4), dysphagia (n = 1), balance disturbance (n = 1), quadrantanopia (n = 1), and memory impairment (n = 1). Persistent neurological deficits occurred in 3 patients (11%), consisting of mild hemiparesis (n = 1), quadrantanopia (n = 1), and memory impairment (n = 1). Postoperative opioid use was recorded in one case (4%), and corticosteroids were administered in 13 patients (48%), most commonly for ≤ 3 days. The length of hospital stay was 1 day in 18 patients (67%), 2 days in 5 (19%), and ≥ 3 days in 4 (15%). There were no postoperative infections or readmissions within 30 days. Among the children with hypothalamic hamartoma (n = 6, Fig. 1.1A-C) all had perioperative extensive endocrinological work-up and pre- and postoperative neuropsychological assessment. Two experienced transient postoperative appetite changes (one increased, one decreased). One child was evaluated postoperatively for suspected central precocious puberty and was subsequently found to have developed postoperative hypothyroidism requiring treatment. No additional enduring endocrinological deficits were observed in the cohort. In four children, neither patient- nor parent-reported assessments revealed postoperative memory complaints, apart from cognitive fatigability. One child demonstrated a possible subtle decline in verbal memory despite improvement on broader cognitive testing. The final patient developed marked postoperative memory impairment, consistent with injury to the fornices. Figure 1 . Illustrative pediatric LITT cases. Preoperative MRI (A), early postoperative MRI (B), and follow-up MRI (C) at 12 months (Fig. 1 ), 16 months (Fig. 2), and 12 months (Fig. 3) showing post-treatment changes in hypothalamic hamartoma (1), subependymal giant cell astrocytoma (2), and pilocytic astrocytoma (3), respectively. Table 1 Patient demographics and operative data Variable n (%) or mean (range) Total patients 27 Indication Drug-resistant epilepsy 18 (67%) Tumor growth 9 (33%) Age (years, mean [range]) 12 (2–18) Sex Female 14 (52%) Male 13 (48%) Location Temporal 7 Parietal 2 Occipital 1 Frontal 2 Insula 1 Region of hypothalamus 6 Thalamus 1 Corpus callosum 3 Intraventricular 2 Cerebellum 2 Stereotactic technique Frame-based (CRW) 23 (85%) SmartFrame (ClearPoint) 4 (15%) Biopsy in same session 10 (37%) Awake treatment 1 (4%) Number of fibers 1 25 (93%) 2 1 (4%) 3 1 (4%) Diffusion tip length (mm) 3 mm 1 (4%) 10 mm 26 (96%) Number of retractions (median [range]) 1 (0–5) Ablation size (cm³, mean [range]) 2.5 (0.2–11) Operative time (min, mean [range]) 171 (104–335) Complications None 19 (70%) Transient neurological deficit 8 (30%) Persistent neurological deficit 3 (11%) Postoperative opioids 1 (4%) Postoperative steroids None 14 (52%) 3 days 8 (30%) ≥3 days 5 (19%) In-hospital length of stay (days) 1 18 (67%) 2 5 (19%) ≥3 4 (15%) Readmission within 30 days 0 (0%) Values are expressed as n (%) unless otherwise specified. LITT: Laser interstitial thermal therapy. Epilepsy outcomes Among the 18 patients treated for epilepsy, lesion types included hypothalamic hamartoma (n = 6), mesial temporal sclerosis (n = 3), extratemporal MRI-negative epilepsy (n = 3), focal cortical dysplasia (n = 2), ganglioglioma (n = 2), astrocytoma (n = 1, Fig. 1.3A-C), and corpus callosotomy (n = 1). The mean age at seizure onset was 5 years, with a mean interval of 7 years from epilepsy onset to LITT. The mean number of antiseizure medications at treatment was 2 (range, 0–4). All patients not receiving antiseizure medications (ASM) at the time of LITT had hypothalamic hamartomas, where seizures particularly gelastic seizures are typically pharmacoresistant. Prior interventions included resective surgery in one patient (6%) in whom LITT was used to target residual orbitofrontal dysplasia. In five patients (28%) the ablation was guided by prior SEEG. Seizure freedom (Engel class I) was achieved in 71% of patients at 6 months, 63% at 1 year, and 57% at 2 years (Table 2 ). In total 82% (14/17) of the patients had seizure reduction at 1 year follow-up and 18% (3/17) had no appreciable change. Among patients with MRI-negative epilepsy, none of the three patients were seizure free at 1 year (Engel IA), compared with 85% (11/13) in the MRI-positive group. The median follow-up duration was 19.5 months (range, 6–48 months). Table 2 Epilepsy cohort: Indications and seizure outcomes Indication n Sz freedom at 1-year % Hypothalamic hamartoma 6 6/6 100 Mesial temporal sclerosis 3 2/3 67 Extratemporal MRI negative 3 0/3 0 Dysplasia 2 1/2 50 Ganglioglioma 2 1/1 100 Astrocytoma 1 1/1 100 Corpus callosotomy 1 0/1 0 Seizure outcome (Engel Classification 1 ) Engel Class 2-years 1-year 6-months Engel I 4 (57%) 11 (65%) 12 (71%) Engel II 0 1 1 Engel III 1 2 3 Engel IV 3 3 2 Other Parameters Variable Value Length of follow-up (months, median) 19.5 (6–48) Age at epilepsy onset (mean) 5 Time from epilepsy onset to LITT (years, mean) 7 Number of ASM at time of LITT (mean) 2 (0–4) Prior interventions None 17 Craniotomy 1 SEEG 5 Values are expressed as n (range). ASM: antiseizure medication; SEEG: stereoelectroencephalography. 1 Engel classification: Engel class I , seizure freedom or auras only; class II , rare disabling seizures; class III , worthwhile improvement; and class IV , no worthwhile improvement. Tumor outcomes Nine patients underwent LITT for tumor indications (Table 3 ), including low-grade glioma in patients with neurofibromatosis type-1 (n = 4), subependymal giant cell astrocytoma in patients with tuberous sclerosis (SEGA; n = 2, Fig. 1.2A-C), glioneuronal tumor (n = 2), and ependymoma (n = 1). The median follow-up duration was 10 months (range, 1–24 months). More than six months follow-up was available in 5 of 9 patients (56%), demonstrating tumor shrinkage and control in 4 (80%) and recurrence in 1 (20%). The latter patient had undergone four prior resections and radiation therapy for a recurrent anaplastic ependymoma (type A) located in the parieto-occipital region and the cerebellum/fourth ventricle and was treated with LITT using two catheters. Tumor recurrence occurred 93 days after LITT, and the patient died 334 days post-procedure. Table 3 Tumor cohort: Indications and follow-up outcomes Variable Value Indication Low-grade glioma 4 SEGA 2 Glioneural 2 Ependymoma 1 Length of follow-up (months, median) 15 (3–29) 6 months FU imaging available 5/9 Tumor recurrence 1/5 Tumor shrinkage at last FU 4/5 Values are expressed as n (range) or proportion. SEGA: subependymal giant cell astrocytoma; FU: follow-up. Discussion This prospective single-center cohort addresses an important evidence gap in pediatric neurosurgery by providing prospectively collected data on safety and early outcomes of LITT across both epilepsy and tumor indications. Overall, we show that among 27 consecutively treated children, we observed no intraoperative complications, with a low rate of persistent neurological deficits, and short hospital stays. Only one patient required opioids after surgery, and steroids were administered postoperatively to half of the patients, typically for a brief period. Stereotactic biopsy in the same session was performed in ten patients and did not compromise the subsequent ablation. Seizure freedom was achieved in 71% of epilepsy patients at six months, 63% at one year, and 57% at two years, and all low-grade tumors demonstrated radiographic volume reduction at last follow-up. Taken together, these findings support LITT as a safe and efficient minimally invasive option in a real-world pediatric setting. Role of LITT in pediatric epilepsy surgery In the epilepsy subgroup, seizure outcomes in the present cohort are broadly comparable to those reported in the largest retrospective pediatric LITT series and pooled analyses, which describe Engel class I rates of approximately 57%, with the most favorable results observed in lesional epilepsies and hypothalamic hamartomas [ 4 , 23 ]. Our prospective study confirms this pattern, with excellent seizure control in hypothalamic hamartomas and other well-defined lesions, and less favorable outcomes in MRI-negative epilepsies. When compared with conventional resective epilepsy surgery, which can achieve seizure freedom in up to two thirds of carefully selected children with focal lesional epilepsy at two-year follow-up [ 6 ], LITT appears capable of providing comparable seizure control in appropriately selected cases while reducing morbidity related to surgical access and shortening postoperative recovery. These characteristics support a role for LITT as a minimally invasive alternative for deep-seated or surgically challenging epileptogenic lesions, particularly when open resection carries increased risk. However, its effectiveness is highly dependent on accurate lesion localization and target definition, underscoring the continued importance of comprehensive presurgical evaluation and careful patient selection. Role of LITT in pediatric neuro-oncology In the tumor cohort, LITT achieved cytoreduction and tumor control in all patients with low-grade tumors and more than 6 months follow-up. One patient with a recurrent multifocal anaplastic posterior fossa type-A ependymoma experienced tumor recurrence, a finding that likely reflects the aggressive biological behavior of this entity rather than limitations of the ablation itself, as further cytoreduction was unlikely to alter the natural disease course. Our findings are consistent with prior retrospective studies in which LITT has been used primarily for LGGs, GGs, SEGAs, and occasional ependymomas, frequently in deep or surgically complex locations such as the mediotemporobasal region, insula, cingulate gyrus, basal ganglia, hypothalamus, brainstem and the cerebellum [ 1 – 3 , 8 , 13 , 14 , 22 ]. A particular advantage of LITT in children is the potential to reduce exposure to repeated general anesthesia by combining diagnostic biopsy and therapeutic ablation within a single operative session. Same-session biopsy enables timely histopathological and molecular characterization, which is increasingly relevant given the expanding role of targeted therapies in pediatric neuro-oncology. Targeted treatments are now available for a broad spectrum of low-grade gliomas [ 5 , 16 ]; however, in cases of treatment failure, progression, or diagnostic uncertainty, the combination of biopsy and LITT offers a minimally invasive alternative that preserves future treatment options. Advantages and limitations of LITT compared with other treatment modalities Compared to open surgery, LITT offers lower access-related morbidity with the possibility of shorter hospital stays, and faster recovery, but with inherent limitations in the achievable extent of ablation. These advantages are particularly relevant for small, deep-seated, or eloquently located lesions. Compared with SEEG-guided radiofrequency ablation, which is attractive for highly focal cortical lesions such as periventricular heterotopias but is inherently limited by small ablation volumes and the absence of real-time visualization of thermal spread, LITT provides continuous MR thermometry, more predictable and homogeneous thermal injury, and the capacity to create substantially larger ablative volumes. In relation to radiosurgery or Gamma Knife, LITT confers three key advantages: first, histological and molecular diagnosis can be obtained in the same session through stereotactic biopsy, enabling tailored oncologic management; second, the ablative effect is immediate, and third, the ablated lesion can be re-treated or subsequently resected if progression occurs, without the cumulative dose limitations inherent to radiation. For selected pediatric patients, especially those with deep low-grade tumors, LITT therefore represents a pragmatic compromise between oncological control, access to tissue, and minimization of long-term treatment-related toxicity. Strengths and limitations Key strengths of this study include its national, prospective design, which ensured complete case inclusion and minimized selection bias by consecutively capturing all pediatric LITT procedures performed in the country, independent of outcomes. The use of a standardized data collection framework enabled consistent recording of demographic, clinical, radiological, technical, and outcome variables. All procedures were performed at a single high-volume national referral center, providing uniformity in surgical technique and perioperative care. However, several limitations of this study must be acknowledged. The heterogeneity of the cohort, including epilepsy and tumor indications across varied lesion locations, reflects real-world practice but limits subgroup analyses and indication-specific conclusions. The sample size is modest and the follow-up is relatively short, particularly for assessing long-term seizure recurrence, tumor progression, and neurocognitive trajectories. In some cases, LITT was offered to children with complex or previously extensively treated disease, often when conventional options were exhausted or associated with substantial risk, which may bias outcomes downward relative to first line use in more straightforward lesions. Our findings also derive from a single national center during the early phase of LITT implementation, which may limit generalizability to units with different case mixes and technologies. Finally, in the absence of a matched control group treated with resection, radiosurgery, or SEEG-guided ablation, we cannot draw definitive comparative effectiveness conclusions. Future perspectives Future work in this area should aim to clarify not only the clinical indications but also the biological effects of LITT. Experimental and early clinical data indicate that thermal ablation transiently disrupts the blood–brain barrier, which may enhance penetration of systemic agents into the perilesional zone and provide a therapeutic window for early adjuvant chemotherapy, targeted therapy, or immunotherapy [ 11 ]. Thermal injury may also modulate the local immune microenvironment by releasing tumor antigens and danger-associated molecular patterns, potentially augmenting anti-tumor immune responses [ 7 , 21 ]. These effects are particularly relevant in pediatric neuro-oncology, where minimizing radiation exposure and leveraging targeted or immune-based treatments are central goals. Prospective multicenter studies and registries will be essential to define optimal timing and sequencing of systemic therapies relative to LITT, to standardize ablation parameters and imaging endpoints, and to explore whether immune or BBB-modulating effects translate into improved long-term disease control. Conclusion In this nationwide prospective cohort of 27 consecutively treated children, LITT was associated with a favorable safety profile for both epilepsy and tumor indications, characterized by the absence of intraoperative complications, low rates of persistent morbidity, and short hospital stay. Same-session biopsy is feasible and does not appear to compromise ablation efficiency. Seizure outcomes in carefully selected epilepsy cases and radiographic responses in low-grade tumors support LITT as a useful alternative when open surgery carries elevated risk. These findings provide practical early benchmarks for pediatric LITT implementation and underscore the need for larger multicenter studies to define long-term outcomes and optimal patient selection. Declarations Competing Interests S.H.N. and R.R. report receiving funded travel support from Medtronic and have co-organized a scientific conference with Medtronic as a co-sponsor. Medtronic is the manufacturer of the laser interstitial thermal therapy (LITT) system used in this study. Medtronic had no role in the study design, data collection, data analysis, interpretation of the results, or manuscript preparation. The remaining authors declare no financial or non-financial competing interests relevant to this work. Ethics Approval This study was approved by the National Danish Research Ethics Committee (Project ID: H-21047703). Consent to Participate In accordance with national regulations, informed consent to participate was not required for this study. Consent to Publication In accordance with the ethical approval obtained, consent for publication was not required. Funding This study was funded by the Danish Comprehensive Cancer Center, the Brain Tumor Center, and the Copenhagen University Hospital, Rigshospitalet Research Fund. Author Contribution S.H.N. collected and compiled the data, performed the main analyses, prepared figures and tables, and drafted the main manuscript text. All authors critically revised the manuscript, approved the final version, and agree to be accountable for all aspects of the work. Acknowledgement We thank the patients and their families for their participation in this study. Data Availability No datasets were generated or analyzed during the current study. References Aboubakr O, Guida L, Dangouloff Ros V et al (2025) Laser Interstitial Thermal Therapy (LITT) in pediatric neurosurgery: Single center retrospective analysis of 41 consecutive procedures. 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J Neurosurg Pediatr 1–8 Additional Declarations Competing interest reported. S.H.N. and R.R. report receiving funded travel support from Medtronic and have co-organized a scientific conference with Medtronic as a co-sponsor. Medtronic is the manufacturer of the laser interstitial thermal therapy (LITT) system used in this study. Medtronic had no role in the study design, data collection, data analysis, interpretation of the results, or manuscript preparation. The remaining authors declare no financial or non-financial competing interests relevant to this work. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8831264","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":604551280,"identity":"008f52f6-128a-4877-a6e1-a3e7de6889df","order_by":0,"name":"Silas Haahr Nielsen","email":"data:image/png;base64,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","orcid":"","institution":"Rigshospitalet","correspondingAuthor":true,"prefix":"","firstName":"Silas","middleName":"Haahr","lastName":"Nielsen","suffix":""},{"id":604551281,"identity":"d335b77f-0e02-481a-9f18-5906efde9fe5","order_by":1,"name":"Jon Foss-Skiftesvik","email":"","orcid":"","institution":"Rigshospitalet","correspondingAuthor":false,"prefix":"","firstName":"Jon","middleName":"","lastName":"Foss-Skiftesvik","suffix":""},{"id":604551283,"identity":"1922c015-87d2-4cd9-a143-dde29b0ce761","order_by":2,"name":"Torstein Melling","email":"","orcid":"","institution":"Rigshospitalet","correspondingAuthor":false,"prefix":"","firstName":"Torstein","middleName":"","lastName":"Melling","suffix":""},{"id":604551284,"identity":"301c48e6-b739-4ea2-82c6-07463d069235","order_by":3,"name":"Astrid Sehested","email":"","orcid":"","institution":"Rigshospitalet","correspondingAuthor":false,"prefix":"","firstName":"Astrid","middleName":"","lastName":"Sehested","suffix":""},{"id":604551285,"identity":"e8732b50-8bcc-4047-9fef-f2157671ff0f","order_by":4,"name":"Christina Engel Hoei-Hansen","email":"","orcid":"","institution":"Rigshospitalet","correspondingAuthor":false,"prefix":"","firstName":"Christina","middleName":"Engel","lastName":"Hoei-Hansen","suffix":""},{"id":604551286,"identity":"2e2c5e94-bcbb-40cc-b8d1-1bf28aac82ec","order_by":5,"name":"Michael Thude Callesen","email":"","orcid":"","institution":"Odense University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Michael","middleName":"Thude","lastName":"Callesen","suffix":""},{"id":604551287,"identity":"1c97cf99-e942-42ea-a21f-58f349983a78","order_by":6,"name":"Gorm Oettingen","email":"","orcid":"","institution":"Aarhus University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Gorm","middleName":"","lastName":"Oettingen","suffix":""},{"id":604551288,"identity":"bfc6b946-9515-498e-95b5-77947302134b","order_by":7,"name":"Adam Espe Hansen","email":"","orcid":"","institution":"Rigshospitalet","correspondingAuthor":false,"prefix":"","firstName":"Adam","middleName":"Espe","lastName":"Hansen","suffix":""},{"id":604551289,"identity":"f2468f13-5751-48d7-a3e9-17a100e7659e","order_by":8,"name":"Jane Skjøth-Rasmussen","email":"","orcid":"","institution":"Rigshospitalet","correspondingAuthor":false,"prefix":"","firstName":"Jane","middleName":"","lastName":"Skjøth-Rasmussen","suffix":""},{"id":604551290,"identity":"f6a3df54-8bdc-4e4f-817c-cf1a9caa0d35","order_by":9,"name":"Rune Rasmussen","email":"","orcid":"","institution":"Rigshospitalet","correspondingAuthor":false,"prefix":"","firstName":"Rune","middleName":"","lastName":"Rasmussen","suffix":""}],"badges":[],"createdAt":"2026-02-09 13:54:28","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8831264/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8831264/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":104867377,"identity":"1c425642-6bc1-4d74-836c-85f121816351","added_by":"auto","created_at":"2026-03-18 07:12:29","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":228602,"visible":true,"origin":"","legend":"\u003cp\u003eIllustrative pediatric LITT cases. Preoperative MRI (A), early postoperative MRI (B), and follow-up MRI (C) at 12 months (Fig. 1), 16 months (Fig. 2), and 12 months (Fig. 3) showing post-treatment changes in hypothalamic hamartoma (1), subependymal giant cell astrocytoma (2), and pilocytic astrocytoma (3), respectively.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8831264/v1/d204b4732aafbbefb0456930.png"},{"id":104867588,"identity":"bea62bea-8237-435e-8088-9e5782aa52e9","added_by":"auto","created_at":"2026-03-18 07:13:17","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1195426,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8831264/v1/8d500bdf-f0e0-425c-a966-c343dd94702f.pdf"}],"financialInterests":"Competing interest reported. S.H.N. and R.R. report receiving funded travel support from Medtronic and have co-organized a scientific conference with Medtronic as a co-sponsor. Medtronic is the manufacturer of the laser interstitial thermal therapy (LITT) system used in this study. Medtronic had no role in the study design, data collection, data analysis, interpretation of the results, or manuscript preparation. The remaining authors declare no financial or non-financial competing interests relevant to this work.","formattedTitle":"Laser interstitial thermal therapy in pediatric neurosurgery: A prospective nation-wide study on indications, safety and early outcomes","fulltext":[{"header":"Introduction","content":"\u003cp\u003eMRI-guided laser interstitial thermal therapy (LITT) is a minimally invasive neurosurgical technique that enables targeted thermal ablation of intracranial lesions. By delivering controlled near-infrared energy through a stereotactically placed laser fiber with real-time temperature monitoring, LITT achieves precise tissue ablation while minimizing injury to surrounding brain structures. The technique has emerged as a promising alternative to conventional open surgery for lesions located in deep or eloquent regions where resection carries substantial risk.\u003c/p\u003e \u003cp\u003eSince its clinical introduction in 2018 in Europe, LITT has been increasingly adopted for a range of neurological conditions [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. In adults, evidence in neuro-oncology consists of retrospective and prospective case series and supports the safety and efficacy of this technique for newly diagnosed and recurrent gliomas, as well as previously irradiated or deep-seated secondary brain tumors [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. For epilepsy, LITT has shown seizure control rates comparable to open resection in matched cohorts, and with the advantages of shorter hospital stays, fewer complications, and fewer permanent neurological deficits [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn pediatric neurosurgery, evidence for the use of LITT remains more limited. A recent systematic review and pooled analysis of 354 pediatric patients with drug-resistant epilepsy reported seizure freedom (Engel class I) in 57% at a mean follow-up of 16 months, with the best outcomes observed in patients with lesional epilepsy and hypothalamic hamartomas [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. For pediatric brain tumors, conventional treatment continues to rely on open resection, which carries a risk of morbidity due to surgical access in deep-seated or midline lesions. The minimally invasive nature of LITT offers the potential to address selected tumors while reducing morbidity and facilitating early postoperative recovery and adjuvant therapy. Pediatric case series have demonstrated the feasibility of LITT for diverse pathologies, including low-grade gliomas (LGGs), ganglioglioma, dysembryoplastic neuroepithelial tumors (DNETs), subependymal giant cell astrocytoma (SEGAs), and ependymomas, with encouraging safety profiles [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Nonetheless, most available data derive from single-center, retrospective cohorts, underscoring the need for systematically collected, prospective evidence [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn pediatric tumor neurosurgery, obtaining a tissue diagnosis with contemporary molecular profiling is central to treatment planning, particularly for low-grade gliomas in which targeted therapies are increasingly used [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Several pediatric LITT series have reported performing stereotactic biopsy in the same session as ablation, demonstrating technical feasibility [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. However, these data are limited to small or retrospective experiences, and no prospective studies have, to our knowledge, systematically evaluated the safety of combined biopsy and LITT in children.\u003c/p\u003e \u003cp\u003eTo address these gaps, we conducted a four-year prospective cohort study of consecutively treated pediatric patients undergoing LITT at a national referral center in Denmark. The study aimed to evaluate operative safety, length of stay, and early clinical and radiographic outcomes across epilepsy and tumor indications, providing one of the first systematically collected prospective datasets in the pediatric LITT field.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy design and inclusion\u003c/h2\u003e \u003cp\u003e This prospective cohort study was approved by the National Danish Research Ethics Committee (Project ID: H-21047703). All pediatric patients (\u0026le;\u0026thinsp;18 years) who underwent LITT at Rigshospitalet between June 1, 2021, and October 31, 2025, were consecutively enrolled.\u003c/p\u003e \u003cp\u003ePatients treated with LITT for epilepsy indications were evaluated and followed according to the Danish National Epilepsy Surgery Program, including a standardized preoperative workup and a 2-year postoperative follow-up. The indication for LITT in epilepsy cases was established at a multidisciplinary epilepsy surgery conference. Indications for LITT in oncological cases were determined at a national multidisciplinary tumor board.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eData collection\u003c/h3\u003e\n\u003cp\u003e Demographic, clinical, radiological, surgical, and outcome data were prospectively obtained from electronic medical records and imaging archives. Recorded variables included sex, age at treatment, indication (drug-resistant epilepsy or tumor growth), and lesion location. Surgical parameters comprised stereotactic technique, biopsy in same session as LITT, awake setup, number of laser fibers, diffusion tip length (3 or 10 mm), number of retractions, ablation volume including the contrast enhancing-rim (volume was calculated using the ellipsoid approximation: V = (π/6) \u0026times; length \u0026times; height \u0026times; width), and operative time (defined as the interval from stereotactic setup to skin closure following catheter removal).\u003c/p\u003e \u003cp\u003ePostoperative variables included steroid and opioid use, length of stay, postoperative disposition, and 30-day readmission. Complications were categorized as none, transient neurological deficit (resolved within 30 days), or persistent deficit (present beyond 3 months). Hypothalamic hamartoma\u0026ndash;specific sequelae (weight gain, appetite change, memory disturbance, or endocrinologic abnormalities) were also recorded.\u003c/p\u003e \u003cp\u003eFollow-up data included clinical and radiographic outcomes and length of follow-up. For epilepsy patients, etiology, age at seizure onset, latency to LITT, number of antiseizure medications (ASMs) at treatment, prior interventions, and Engel classification at 6, 12, and 24 months were collected. For tumor patients, histology, recurrence, and radiographic response at last follow-up were documented. Time to last follow-up, survival status, and date of last contact were noted for all patients.\u003c/p\u003e\n\u003ch3\u003eSurgical technique\u003c/h3\u003e\n\u003cp\u003eAll procedures were performed using the Visualase system (Medtronic, Minneapolis, MN, USA). Laser catheter placement and, when indicated, biopsy were guided by either a frame-based stereotactic system (Cosman\u0026ndash;Robert\u0026ndash;Wells, Integra LifeSciences, Plainsboro, NJ, USA) or an MRI-guided SmartFrame Array (ClearPoint Neuro, Irvine, CA, USA). The SmartFrame system was preferentially used for small, deep-seated targets requiring high stereotactic accuracy, which in this case series included hypothalamic hamartomas. Image registration and trajectory verification were performed using an intraoperative CT scanner (AIRO, Brainlab AG, Munich, Germany). Real-time MR thermography was conducted on a 1.5-T intraoperative MRI system (GE Healthcare, Chicago, IL, USA).\u003c/p\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eContinuous variables are reported as mean (range) or median (range), as appropriate; categorical variables are presented as counts and percentages.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eCohort characteristics\u003c/h2\u003e \u003cp\u003eA total of 27 pediatric patients (mean age 12 years; range, 2\u0026ndash;18 years) underwent LITT between June 2021 and October 2025 (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The cohort comprised 14 females (52%) and 13 males (48%). The primary indication was drug-resistant epilepsy in 18 patients (67%) and tumor growth in 9 patients (33%). Lesion locations included the temporal lobe (n\u0026thinsp;=\u0026thinsp;7), hypothalamic region (n\u0026thinsp;=\u0026thinsp;6), corpus callosum (n\u0026thinsp;=\u0026thinsp;3), parietal lobe (n\u0026thinsp;=\u0026thinsp;2), frontal lobe (n\u0026thinsp;=\u0026thinsp;2), intraventricular region (n\u0026thinsp;=\u0026thinsp;2), and cerebellum (n\u0026thinsp;=\u0026thinsp;2), as well as the occipital, thalamic, and insular regions (n\u0026thinsp;=\u0026thinsp;1).\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eProcedural characteristics\u003c/h3\u003e\n\u003cp\u003eA frame-based stereotactic system was used in 23 cases (85%), while the MRI-guided SmartFrame was applied in 4 cases (15%) [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e], the latter all targeting hypothalamic hamartomas. Same-session biopsy was performed in 10 patients, including 7 with tumor indications (excluding subependymal giant cell astrocytomes (SEGAs)) and 3 epilepsy patients in whom a low-grade glioma or glioneuronal tumor was suspected. There were no biopsy related complications, and the combined approach did not compromise the subsequent ablation, defined as no bleeding or air artifact interference.\u003c/p\u003e \u003cp\u003eOne patient underwent awake LITT with intraoperative language testing; the ablation was tailored to reduce the risk of permanent postoperative aphasia [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The procedure included preoperative constrained spherical deconvolution (CSD) tractography performed with Quicktome software (Omniscient Neurotechnology) and intraoperative language assessment after controlled temperature increase to approximately 46\u0026deg;C for less than 30 seconds.\u003c/p\u003e \u003cp\u003eA single laser fiber was used in 25 patients (93%), two fibers in 1 patient (4%), and three fibers in 1 patient (4%). The diffusion-tip length was 10 mm in 26 cases and 3 mm in 1 case. The median number of retractions was 1 (range, 0\u0026ndash;5). The mean ablation volume was 2.5 cm\u0026sup3; (range, 0.2\u0026ndash;11 cm\u0026sup3;), and the mean ablation diameter was 1.3 cm (range, 0.7\u0026ndash;1.9 cm). The mean operative time was 171 minutes (range, 104\u0026ndash;335 minutes). When using the MRI SmartFrame, the mean operative time was 270 minutes, compared with 153 minutes when using the frame-based stereotactic system.\u003c/p\u003e\n\u003ch3\u003eIntraoperative complications and postoperative course\u003c/h3\u003e\n\u003cp\u003eNo intraoperative complications occurred, and there were no cases of catheter repositioning, hemorrhage, or anesthesiologic complications. Postoperatively, 19 patients (70%) had no new neurological deficits. Transient neurological deficits were observed in 8 patients (30%) and included motor deficits (n\u0026thinsp;=\u0026thinsp;4), dysphagia (n\u0026thinsp;=\u0026thinsp;1), balance disturbance (n\u0026thinsp;=\u0026thinsp;1), quadrantanopia (n\u0026thinsp;=\u0026thinsp;1), and memory impairment (n\u0026thinsp;=\u0026thinsp;1). Persistent neurological deficits occurred in 3 patients (11%), consisting of mild hemiparesis (n\u0026thinsp;=\u0026thinsp;1), quadrantanopia (n\u0026thinsp;=\u0026thinsp;1), and memory impairment (n\u0026thinsp;=\u0026thinsp;1).\u003c/p\u003e \u003cp\u003ePostoperative opioid use was recorded in one case (4%), and corticosteroids were administered in 13 patients (48%), most commonly for \u0026le;\u0026thinsp;3 days. The length of hospital stay was 1 day in 18 patients (67%), 2 days in 5 (19%), and \u0026ge;\u0026thinsp;3 days in 4 (15%). There were no postoperative infections or readmissions within 30 days.\u003c/p\u003e \u003cp\u003eAmong the children with hypothalamic hamartoma (n\u0026thinsp;=\u0026thinsp;6, Fig.\u0026nbsp;1.1A-C) all had perioperative extensive endocrinological work-up and pre- and postoperative neuropsychological assessment. Two experienced transient postoperative appetite changes (one increased, one decreased). One child was evaluated postoperatively for suspected central precocious puberty and was subsequently found to have developed postoperative hypothyroidism requiring treatment. No additional enduring endocrinological deficits were observed in the cohort.\u003c/p\u003e \u003cp\u003eIn four children, neither patient- nor parent-reported assessments revealed postoperative memory complaints, apart from cognitive fatigability. One child demonstrated a possible subtle decline in verbal memory despite improvement on broader cognitive testing. The final patient developed marked postoperative memory impairment, consistent with injury to the fornices.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Illustrative pediatric LITT cases. Preoperative MRI (A), early postoperative MRI (B), and follow-up MRI (C) at 12 months (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), 16 months (Fig.\u0026nbsp;2), and 12 months (Fig.\u0026nbsp;3) showing post-treatment changes in hypothalamic hamartoma (1), subependymal giant cell astrocytoma (2), and pilocytic astrocytoma (3), respectively.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePatient demographics and operative data\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003en (%) or mean (range)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal patients\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIndication\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDrug-resistant epilepsy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18 (67%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTumor growth\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9 (33%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (years, mean [range])\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (2\u0026ndash;18)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14 (52%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13 (48%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLocation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTemporal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParietal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOccipital\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFrontal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInsula\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRegion of hypothalamus\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eThalamus\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCorpus callosum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIntraventricular\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCerebellum\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eStereotactic technique\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFrame-based (CRW)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e23 (85%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSmartFrame (ClearPoint)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (15%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBiopsy in same session\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10 (37%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAwake treatment\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (4%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of fibers\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25 (93%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (4%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (4%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiffusion tip length (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (4%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e10 mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e26 (96%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of retractions (median [range])\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (0\u0026ndash;5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAblation size (cm\u0026sup3;, mean [range])\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.5 (0.2\u0026ndash;11)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOperative time (min, mean [range])\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e171 (104\u0026ndash;335)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eComplications\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e19 (70%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTransient neurological deficit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8 (30%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePersistent neurological deficit\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3 (11%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostoperative opioids\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (4%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePostoperative steroids\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14 (52%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3 days\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8 (30%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026ge;3 days\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 (19%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIn-hospital length of stay (days)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e18 (67%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 (19%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026ge;3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (15%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eReadmission within 30 days\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0 (0%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eValues are expressed as n (%) unless otherwise specified. LITT: Laser interstitial thermal therapy.\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eEpilepsy outcomes\u003c/h2\u003e \u003cp\u003eAmong the 18 patients treated for epilepsy, lesion types included hypothalamic hamartoma (n\u0026thinsp;=\u0026thinsp;6), mesial temporal sclerosis (n\u0026thinsp;=\u0026thinsp;3), extratemporal MRI-negative epilepsy (n\u0026thinsp;=\u0026thinsp;3), focal cortical dysplasia (n\u0026thinsp;=\u0026thinsp;2), ganglioglioma (n\u0026thinsp;=\u0026thinsp;2), astrocytoma (n\u0026thinsp;=\u0026thinsp;1, Fig.\u0026nbsp;1.3A-C), and corpus callosotomy (n\u0026thinsp;=\u0026thinsp;1). The mean age at seizure onset was 5 years, with a mean interval of 7 years from epilepsy onset to LITT. The mean number of antiseizure medications at treatment was 2 (range, 0\u0026ndash;4). All patients not receiving antiseizure medications (ASM) at the time of LITT had hypothalamic hamartomas, where seizures particularly gelastic seizures are typically pharmacoresistant. Prior interventions included resective surgery in one patient (6%) in whom LITT was used to target residual orbitofrontal dysplasia. In five patients (28%) the ablation was guided by prior SEEG.\u003c/p\u003e \u003cp\u003eSeizure freedom (Engel class I) was achieved in 71% of patients at 6 months, 63% at 1 year, and 57% at 2 years (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). In total 82% (14/17) of the patients had seizure reduction at 1 year follow-up and 18% (3/17) had no appreciable change. Among patients with MRI-negative epilepsy, none of the three patients were seizure free at 1 year (Engel IA), compared with 85% (11/13) in the MRI-positive group. The median follow-up duration was 19.5 months (range, 6\u0026ndash;48 months).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eEpilepsy cohort: Indications and seizure outcomes\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIndication\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003en\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSz freedom at 1-year\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e%\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHypothalamic hamartoma\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6/6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMesial temporal sclerosis\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2/3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e67\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eExtratemporal MRI negative\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0/3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDysplasia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1/2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGanglioglioma\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1/1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAstrocytoma\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1/1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCorpus callosotomy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0/1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eSeizure outcome (Engel Classification\u003csup\u003e1\u003c/sup\u003e)\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEngel Class\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2-years\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1-year\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6-months\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEngel I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (57%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11 (65%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12 (71%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEngel II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEngel III\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEngel IV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eOther Parameters\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabb\" border=\"1\"\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eValue\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLength of follow-up (months, median)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e19.5 (6\u0026ndash;48)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge at epilepsy onset (mean)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTime from epilepsy onset to LITT (years, mean)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of ASM at time of LITT (mean)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (0\u0026ndash;4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePrior interventions\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCraniotomy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSEEG\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eValues are expressed as n (range). ASM: antiseizure medication; SEEG: stereoelectroencephalography.\u003c/p\u003e \u003cp\u003e \u003csup\u003e1\u003c/sup\u003eEngel classification: \u003cb\u003eEngel class I\u003c/b\u003e, seizure freedom or auras only; \u003cb\u003eclass II\u003c/b\u003e, rare disabling seizures; \u003cb\u003eclass III\u003c/b\u003e, worthwhile improvement; and \u003cb\u003eclass IV\u003c/b\u003e, no worthwhile improvement.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eTumor outcomes\u003c/h2\u003e \u003cp\u003eNine patients underwent LITT for tumor indications (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e), including low-grade glioma in patients with neurofibromatosis type-1 (n\u0026thinsp;=\u0026thinsp;4), subependymal giant cell astrocytoma in patients with tuberous sclerosis (SEGA; n\u0026thinsp;=\u0026thinsp;2, Fig.\u0026nbsp;1.2A-C), glioneuronal tumor (n\u0026thinsp;=\u0026thinsp;2), and ependymoma (n\u0026thinsp;=\u0026thinsp;1). The median follow-up duration was 10 months (range, 1\u0026ndash;24 months). More than six months follow-up was available in 5 of 9 patients (56%), demonstrating tumor shrinkage and control in 4 (80%) and recurrence in 1 (20%). The latter patient had undergone four prior resections and radiation therapy for a recurrent anaplastic ependymoma (type A) located in the parieto-occipital region and the cerebellum/fourth ventricle and was treated with LITT using two catheters. Tumor recurrence occurred 93 days after LITT, and the patient died 334 days post-procedure.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eTumor cohort: Indications and follow-up outcomes\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eValue\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIndication\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLow-grade glioma\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSEGA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGlioneural\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEpendymoma\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLength of follow-up (months, median)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15 (3\u0026ndash;29)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6 months FU imaging available\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5/9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTumor recurrence\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1/5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTumor shrinkage at last FU\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4/5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eValues are expressed as n (range) or proportion. SEGA: subependymal giant cell astrocytoma; FU: follow-up.\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis prospective single-center cohort addresses an important evidence gap in pediatric neurosurgery by providing prospectively collected data on safety and early outcomes of LITT across both epilepsy and tumor indications. Overall, we show that among 27 consecutively treated children, we observed no intraoperative complications, with a low rate of persistent neurological deficits, and short hospital stays. Only one patient required opioids after surgery, and steroids were administered postoperatively to half of the patients, typically for a brief period. Stereotactic biopsy in the same session was performed in ten patients and did not compromise the subsequent ablation. Seizure freedom was achieved in 71% of epilepsy patients at six months, 63% at one year, and 57% at two years, and all low-grade tumors demonstrated radiographic volume reduction at last follow-up.\u003c/p\u003e \u003cp\u003eTaken together, these findings support LITT as a safe and efficient minimally invasive option in a real-world pediatric setting.\u003c/p\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eRole of LITT in pediatric epilepsy surgery\u003c/h2\u003e \u003cp\u003eIn the epilepsy subgroup, seizure outcomes in the present cohort are broadly comparable to those reported in the largest retrospective pediatric LITT series and pooled analyses, which describe Engel class I rates of approximately 57%, with the most favorable results observed in lesional epilepsies and hypothalamic hamartomas [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Our prospective study confirms this pattern, with excellent seizure control in hypothalamic hamartomas and other well-defined lesions, and less favorable outcomes in MRI-negative epilepsies. When compared with conventional resective epilepsy surgery, which can achieve seizure freedom in up to two thirds of carefully selected children with focal lesional epilepsy at two-year follow-up [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], LITT appears capable of providing comparable seizure control in \u003cem\u003eappropriately selected cases\u003c/em\u003e while reducing morbidity related to surgical access and shortening postoperative recovery. These characteristics support a role for LITT as a minimally invasive alternative for deep-seated or surgically challenging epileptogenic lesions, particularly when open resection carries increased risk. However, its effectiveness is highly dependent on accurate lesion localization and target definition, underscoring the continued importance of comprehensive presurgical evaluation and careful patient selection.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eRole of LITT in pediatric neuro-oncology\u003c/h2\u003e \u003cp\u003eIn the tumor cohort, LITT achieved cytoreduction and tumor control in all patients with low-grade tumors and more than 6 months follow-up. One patient with a recurrent multifocal anaplastic posterior fossa type-A ependymoma experienced tumor recurrence, a finding that likely reflects the aggressive biological behavior of this entity rather than limitations of the ablation itself, as further cytoreduction was unlikely to alter the natural disease course. Our findings are consistent with prior retrospective studies in which LITT has been used primarily for LGGs, GGs, SEGAs, and occasional ependymomas, frequently in deep or surgically complex locations such as the mediotemporobasal region, insula, cingulate gyrus, basal ganglia, hypothalamus, brainstem and the cerebellum [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. A particular advantage of LITT in children is the potential to reduce exposure to repeated general anesthesia by combining diagnostic biopsy and therapeutic ablation within a single operative session. Same-session biopsy enables timely histopathological and molecular characterization, which is increasingly relevant given the expanding role of targeted therapies in pediatric neuro-oncology. Targeted treatments are now available for a broad spectrum of low-grade gliomas [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]; however, in cases of treatment failure, progression, or diagnostic uncertainty, the combination of biopsy and LITT offers a minimally invasive alternative that preserves future treatment options.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eAdvantages and limitations of LITT compared with other treatment modalities\u003c/h2\u003e \u003cp\u003eCompared to open surgery, LITT offers lower access-related morbidity with the possibility of shorter hospital stays, and faster recovery, but with inherent limitations in the achievable extent of ablation. These advantages are particularly relevant for small, deep-seated, or eloquently located lesions.\u003c/p\u003e \u003cp\u003eCompared with SEEG-guided radiofrequency ablation, which is attractive for highly focal cortical lesions such as periventricular heterotopias but is inherently limited by small ablation volumes and the absence of real-time visualization of thermal spread, LITT provides continuous MR thermometry, more predictable and homogeneous thermal injury, and the capacity to create substantially larger ablative volumes.\u003c/p\u003e \u003cp\u003eIn relation to radiosurgery or Gamma Knife, LITT confers three key advantages: first, histological and molecular diagnosis can be obtained in the same session through stereotactic biopsy, enabling tailored oncologic management; second, the ablative effect is immediate, and third, the ablated lesion can be re-treated or subsequently resected if progression occurs, without the cumulative dose limitations inherent to radiation. For selected pediatric patients, especially those with deep low-grade tumors, LITT therefore represents a pragmatic compromise between oncological control, access to tissue, and minimization of long-term treatment-related toxicity.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eStrengths and limitations\u003c/h2\u003e \u003cp\u003eKey strengths of this study include its national, prospective design, which ensured complete case inclusion and minimized selection bias by consecutively capturing all pediatric LITT procedures performed in the country, independent of outcomes. The use of a standardized data collection framework enabled consistent recording of demographic, clinical, radiological, technical, and outcome variables. All procedures were performed at a single high-volume national referral center, providing uniformity in surgical technique and perioperative care. However, several limitations of this study must be acknowledged. The heterogeneity of the cohort, including epilepsy and tumor indications across varied lesion locations, reflects real-world practice but limits subgroup analyses and indication-specific conclusions. The sample size is modest and the follow-up is relatively short, particularly for assessing long-term seizure recurrence, tumor progression, and neurocognitive trajectories. In some cases, LITT was offered to children with complex or previously extensively treated disease, often when conventional options were exhausted or associated with substantial risk, which may bias outcomes downward relative to first line use in more straightforward lesions. Our findings also derive from a single national center during the early phase of LITT implementation, which may limit generalizability to units with different case mixes and technologies. Finally, in the absence of a matched control group treated with resection, radiosurgery, or SEEG-guided ablation, we cannot draw definitive comparative effectiveness conclusions.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003eFuture perspectives\u003c/h2\u003e \u003cp\u003eFuture work in this area should aim to clarify not only the clinical indications but also the biological effects of LITT. Experimental and early clinical data indicate that thermal ablation transiently disrupts the blood\u0026ndash;brain barrier, which may enhance penetration of systemic agents into the perilesional zone and provide a therapeutic window for early adjuvant chemotherapy, targeted therapy, or immunotherapy [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Thermal injury may also modulate the local immune microenvironment by releasing tumor antigens and danger-associated molecular patterns, potentially augmenting anti-tumor immune responses [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. These effects are particularly relevant in pediatric neuro-oncology, where minimizing radiation exposure and leveraging targeted or immune-based treatments are central goals. Prospective multicenter studies and registries will be essential to define optimal timing and sequencing of systemic therapies relative to LITT, to standardize ablation parameters and imaging endpoints, and to explore whether immune or BBB-modulating effects translate into improved long-term disease control.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn this nationwide prospective cohort of 27 consecutively treated children, LITT was associated with a favorable safety profile for both epilepsy and tumor indications, characterized by the absence of intraoperative complications, low rates of persistent morbidity, and short hospital stay. Same-session biopsy is feasible and does not appear to compromise ablation efficiency. Seizure outcomes in carefully selected epilepsy cases and radiographic responses in low-grade tumors support LITT as a useful alternative when open surgery carries elevated risk. These findings provide practical early benchmarks for pediatric LITT implementation and underscore the need for larger multicenter studies to define long-term outcomes and optimal patient selection.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003cp\u003eS.H.N. and R.R. report receiving funded travel support from Medtronic and have co-organized a scientific conference with Medtronic as a co-sponsor. Medtronic is the manufacturer of the laser interstitial thermal therapy (LITT) system used in this study. Medtronic had no role in the study design, data collection, data analysis, interpretation of the results, or manuscript preparation. The remaining authors declare no financial or non-financial competing interests relevant to this work.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e \u003ch2\u003eEthics Approval\u003c/h2\u003e \u003cp\u003e This study was approved by the National Danish Research Ethics Committee (Project ID: H-21047703).\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConsent to Participate\u003c/strong\u003e \u003cp\u003eIn accordance with national regulations, informed consent to participate was not required for this study.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConsent to Publication\u003c/strong\u003e \u003cp\u003e In accordance with the ethical approval obtained, consent for publication was not required.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eThis study was funded by the Danish Comprehensive Cancer Center, the Brain Tumor Center, and the Copenhagen University Hospital, Rigshospitalet Research Fund.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eS.H.N. collected and compiled the data, performed the main analyses, prepared figures and tables, and drafted the main manuscript text. All authors critically revised the manuscript, approved the final version, and agree to be accountable for all aspects of the work.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eWe thank the patients and their families for their participation in this study.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e \u003cp\u003eNo datasets were generated or analyzed during the current study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAboubakr O, Guida L, Dangouloff Ros V et al (2025) Laser Interstitial Thermal Therapy (LITT) in pediatric neurosurgery: Single center retrospective analysis of 41 consecutive procedures. Neurochirurgie 71(6):101719\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eArocho-Quinones EV, Lew SM, Handler MH et al (2020) Magnetic resonance\u0026ndash;guided stereotactic laser ablation therapy for the treatment of pediatric brain tumors: a multiinstitutional retrospective study. J Neurosurgery: Pediatr 26(1):13\u0026ndash;21\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarros Guinle MI, Johnstone T, Li D, Kaur H, Porter BE, Grant GA (2024) Approach, complications, and outcomes for 37 consecutive pediatric patients undergoing laser ablation for medically refractory epilepsy at Stanford Children\u0026rsquo;s Health. J Neurosurg Pediatr 33(1):1\u0026ndash;11\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen J-S, Lamoureux A-A, Shlobin NA et al (2023) Magnetic resonance-guided laser interstitial thermal therapy for drug-resistant epilepsy: A systematic review and individual participant data meta-analysis. Epilepsia 64(8):1957\u0026ndash;1974\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFrassanito P, Thomale UW, Obersnel M, Romano A, Leblond P, Knerlich-Lukoschus F, Due-T\u0026oslash;nnessen BJ, Thompson D, Di Rocco F, the CPN Lyon 2024 Consensus Conference Group (2025) The state of targeted therapeutic pharmacological approaches in pediatric neurosurgery: report from the European Society for Pediatric Neurosurgery (ESPN) Consensus Conference 2024. Childs Nerv Syst 41(1):149\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHarris WB, Brunette-Clement T, Wang A, Phillips HW, von Der Brelie C, Weil AG, Fallah A (2022) Long-term outcomes of pediatric epilepsy surgery: Individual participant data and study level meta-analyses. Seizure: European Journal of Epilepsy 101:227\u0026ndash;236\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLerner EC, Edwards RM, Wilkinson DS, Fecci PE (2022) Laser ablation: Heating up the anti-tumor response in the intracranial compartment. Adv Drug Deliv Rev 185:114311\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMirone G, Cicala D, Cinalli G (2023) Posterior Fossa Laser Interstitial Thermal Therapy in Children. Neurosurg Clin N Am 34(2):227\u0026ndash;237\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMortezaei A, Al-Saidi N, Taghlabi KM et al (2025) Laser interstitial thermal therapy for high-grade glioma: a systematic review, meta-analysis, and meta-regression. Neurosurg Focus 59(2):E10\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNielsen SH, Rasmussen R (2024) MR-guided laser interstitial thermal therapy in the treatment of brain tumors and epilepsy. Acta Neurochir 166(1):344\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNielsen SH, Skj\u0026oslash;th-Rasmussen J, Larsen VA, Carlsen JF, Larsson HBW, Christoffersen C, Rasmussen R, Hansen AE (2025) Blood-brain barrier disruption following MR-guided Laser Interstitial Thermal Therapy. Neuro-Oncology Advances vdaf148\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNielsen SH, Skj\u0026oslash;th-Rasmussen J, Moldrup SD, Engelmann CM, Jespersen B, Rasmussen R (2023) Awake Laser Ablation with Continuous Neuropsychological Testing During Treatment of Brain Tumors and Epilepsy. Neurosurg Clin North Am 34(2):239\u0026ndash;245\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eO\u0026rsquo;Leary S, Haider MA, Truong N et al (2025) Stereotactic laser ablation for pediatric central nervous system tumors: a systematic review and meta-analysis of the literature. J Neurosurg Pediatr 36(2):230\u0026ndash;243\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePehlivan KC, Khanna PC, Elster JD, Paul MR, Levy ML, Crawford JR, Gonda DD (2021) Clinical and Neuroimaging Features of Magnetic Resonance\u0026ndash;Guided Stereotactic Laser Ablation for Newly Diagnosed and Recurrent Pediatric Brain Tumors: A Single Institutional Series. World Neurosurg 150:e378\u0026ndash;e387\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePichardo-Rojas D, Espinosa-Cant\u0026uacute; CB, Valenzuela-Rangel AF, Choque-Ayala LC, Barr\u0026oacute;n-Lomel\u0026iacute; A, Gutierrez-Herrera EA, Mej\u0026iacute;a P\u0026eacute;rez SI, Pichardo-Rojas PS, Milanese V, Rangel-Castilla L (2025) A comparative assessment of laser interstitial thermal therapy and open resective surgery for drug-resistant epilepsy: a meta-analysis of 3873 patients. J Neurosurg 1\u0026ndash;20\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePlant-Fox AS, Tabori U (2024) Future perspective of targeted treatments in pediatric low-grade glioma (pLGG): the evolution of standard-of-care and challenges of a new era. Childs Nerv Syst 40(10):3291\u0026ndash;3299\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRasmussen R, Nielsen SH (2024) How I do it: MRI-guided stereotactic navigation for Laser Interstitial Thermal Therapy. Acta Neurochir (Wien) 166(1):444\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRoka K, Scheinemann K, Avula S, Maduro JH, Thomale UW, Sehested A, Meeteren AYNS-V (2024) European standard clinical practice recommendations for primary pediatric low-grade gliomas. EJC Pediatr Oncol. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.ejcped.2024.100169\u003c/span\u003e\u003cspan address=\"10.1016/j.ejcped.2024.100169\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRyall S, Tabori U, Hawkins C (2020) Pediatric low-grade glioma in the era of molecular diagnostics. Acta Neuropathol Commun 8(1):30\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSpacca B, Di Maurizio M, Grandoni M, Tempesti S, Genitori L (2023) Laser interstitial thermal therapy (LITT) for pediatric patients affected by intracranial tumors. Front Neurol 14:1120286\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVargas LO, Himic V, Otaner F et al (2025) Modulating the glioma microenvironment with laser interstitial thermal therapy: mechanisms and therapeutic implications. J Neurooncol 176(1):99\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVitulli F, Tortora D, Pacetti M et al (2025) Magnetic Resonance-guided Laser interstitial thermal therapy (MR-gLiTT) in Pediatric Neurosurgery: italian perspective and literature review. Neurol Sci 46(8):3965\u0026ndash;3972\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWoods SB, Shields LBE, Kuruvilla A, Shetty M, Feygin YB, Aras S, Mutchnick IS, Ali I, Karakas C (2025) Magnetic resonance-guided laser interstitial thermal therapy for pediatric drug-resistant epilepsy: a pooled analysis and systematic review of the literature. J Neurosurg Pediatr 1\u0026ndash;12\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZeller S, Kaye J, Jumah F, Mantri SS, Mir J, Raju B, Danish SF (2021) Current applications and safety profile of laser interstitial thermal therapy in the pediatric population: a systematic review of the literature. J Neurosurg Pediatr 1\u0026ndash;8\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"childs-nervous-system","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"cnsy","sideBox":"Learn more about [Child's Nervous System](http://link.springer.com/journal/381)","snPcode":"381","submissionUrl":"https://submission.nature.com/new-submission/381/3","title":"Child's Nervous System","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"laser interstitial thermal therapy, stereotactic laser ablation, pediatric neurosurgery, epilepsy surgery, pediatric brain tumors, minimally invasive","lastPublishedDoi":"10.21203/rs.3.rs-8831264/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8831264/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eTo evaluate indications, safety, and early outcomes of MRI-guided laser interstitial thermal therapy (LITT) in a nationwide prospective pediatric cohort and to assess the feasibility of same-session stereotactic biopsy.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eAll consecutive pediatric patients (\u0026le;\u0026thinsp;18 years) undergoing LITT at the Danish national referral center between June 2021 and October 2025 were prospectively enrolled. Demographic, clinical, radiological, and surgical variables were recorded. Safety outcomes included intraoperative complications, neurological deficits, length of stay, and 30-day readmission. Seizure outcomes were assessed by Engel classification, and tumor response by follow-up MRI.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eA total of 27 children (mean age 12 years, range 2\u0026ndash;18) underwent LITT, including 18 treated for drug-resistant epilepsy and 9 for tumor indications. Same-session stereotactic biopsy was performed in 10 patients without biopsy-related complications or interference with ablation. No intraoperative complications occurred. Transient neurological deficits were observed in 8 patients and persistent deficits in 3. Hospital stay was \u0026le;\u0026thinsp;2 days in 23 patients, and no 30-day readmissions occurred. Seizure freedom (Engel class I) was achieved in 71%, 63%, and 57% at 6, 12, and 24 months, respectively. In tumor patients (median follow-up 15 months), MRI showed tumor control in 4 of 5 cases.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eIn this nationwide prospective cohort of 27 consecutively treated children, LITT was associated with a favorable safety profile for both epilepsy and tumor indications. Same-session stereotactic biopsy was feasible and safe, supporting LITT as a minimally invasive option in selected pediatric patients.\u003c/p\u003e","manuscriptTitle":"Laser interstitial thermal therapy in pediatric neurosurgery: A prospective nation-wide study on indications, safety and early outcomes","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-18 07:10:09","doi":"10.21203/rs.3.rs-8831264/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-04-26T15:43:45+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-13T20:59:53+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-09T08:14:11+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"92504926863269549456822742133631060212","date":"2026-04-02T20:24:24+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"32798022386188702799929361389934320711","date":"2026-04-02T16:27:40+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-03-11T15:12:19+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-02-12T07:17:20+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-02-12T07:11:09+00:00","index":"","fulltext":""},{"type":"submitted","content":"Child's Nervous System","date":"2026-02-09T13:40:34+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"childs-nervous-system","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"cnsy","sideBox":"Learn more about [Child's Nervous System](http://link.springer.com/journal/381)","snPcode":"381","submissionUrl":"https://submission.nature.com/new-submission/381/3","title":"Child's Nervous System","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"454d4f98-5e73-49c4-a0ba-2f0990b2358b","owner":[],"postedDate":"March 18th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-16T15:23:11+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-18 07:10:09","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8831264","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8831264","identity":"rs-8831264","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}