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Background Laser interstitial thermal therapy (LITT) is a minimally invasive alternative to anterior temporal lobectomy (ATL) for treatment of temporal lobe epilepsy. It has gained popularity as familiarity with technique increases and outcomes are better characterized. There has been no direct cost comparison between the 2 techniques in literature to date. The current study directly compares hospital costs associated with LITT with those of ATL patients and analyzes the factors potentially responsible for those costs. Methods Patients who underwent ATL (27) and LITT (15) were retrospectively reviewed for total hospital costs along with demographic, surgical, and postoperative factors potentially affecting cost. T-tests were used to compare costs and independent linear regressions, and hierarchical regressions were used to examine predictors of cost for each procedure. Results Mean hospital costs of admission for single-trajectory LITT ($104,929.88) were significantly less than for ATL ($134,980.04) (P = 0.001). In addition, length of stay, anesthesia costs, operative room costs, and postoperative hospitalization costs were all significantly lower in LITT. Conclusions Given the minimally invasive nature of LITT, it is associated with shorter length of stay and lower hospital costs than ATL in the first head-to-head comparison of procedural costs in literature to date. Long-term efficacy as it relates to these costs associated with LITT and ATL should be further investigated to better characterize the utility of LITT in temporal lobe epilepsy patients.

OBJECTIVE Periventricular nodular heterotopia (PVNH) is a result of disrupted neuronal migration from the ventricular system and can be a rare cause of refractory focal epilepsy. The goal of this case series was to describe the treatment of pediatric PVNH-related epilepsy with MR-guided laser interstitial thermal ablation. METHODS Patients treated at a single institution with MR-guided laser interstitial thermal therapy (MRgLITT) for PVNH-related epilepsy were identified. Preoperative and postoperative seizure outcomes and procedural information were evaluated. RESULTS Five children with PVNH treated with MRgLITT were reviewed; 1 child was treated twice. Three patients were female; the median age was 10.9 years. Five of 6 treatments were preceded by stereoelectroencephalography phase II monitoring. Three children experienced unilateral PVNH, and 2 had bilateral seizures. The median number of seizures recorded during phase II monitoring was 2; the median number of ablation targets was 2 (range 1–4). All patients experienced a decrease in seizure frequency; 4 patients (80%) had an Engel class ≤ III at the last follow-up (range I–IV). One child experienced right hemianopia posttreatment. CONCLUSIONS This case series investigation has illustrated a novel, minimally invasive approach for treating pediatric PVNH-related epilepsy. Further study of this technique with comparison with other surgical techniques is warranted.

Objective Laser interstitial thermal therapy (LITT) is a minimally invasive surgery for mesial temporal lobe epilepsy (mTLE), but the effects of individual patient anatomy and location of ablation volumes affect seizure outcomes. The purpose of this study is to see if features of individual patient structural connectomes predict surgical outcomes after LITT for mTLE. Methods This is a retrospective analysis of seizure outcomes of LITT for mTLE in 24 patients. We use preoperative diffusion tensor imaging (DTI) to simulate changes in structural connectivity after laser ablation. A two-step machine-learning algorithm is applied to predict seizure outcomes from the change in connectomic features after surgery. Results Although node-based network features such as clustering coefficient and betweenness centrality have some predictive value, changes in connection strength between mesial temporal regions predict seizure outcomes significantly better. Changes in connection strength between the entorhinal cortex (EC), and the insula, hippocampus, and amygdala, as well as between the temporal pole and hippocampus, predict Engel Class I outcomes with an accuracy of 88%. Analysis of the ablation location, as well as simulated, alternative ablations, reveals that a more medial, anterior, and inferior ablation volume is associated with a greater effect on these connections, and potentially on seizure outcomes. Significance Our results indicate (1) that seizure outcomes can be retrospectively predicted with excellent accuracy using changes in structural connectivity, and (2) that favorable connectomic changes are associated with an ablation volume involving relatively mesial, anterior, and inferior locations. These results may provide a framework whereby individual pre-operative structural connectomes can be used to optimize ablation volumes and improve outcomes in LITT for mTLE.

Laser interstitial thermal therapy (LiTT) isa minimally invasive alternative to conventional open surgery for drug-resistant focal mesial temporal lobe epilepsy (MTLE). Recent studies suggest that higher seizure freedom rates are correlated with maximal ablation of the mesialhippocampal head, whilst sparing of the parahippocampal gyrus (PHG) may reduce neuropsychological sequelae. Current commercially available laser catheters are inserted following manually planned straight-line trajectories, which cannot conform to curved brain structures, such as the hippocampus, without causing collateral damage or requiring multiple insertions. Objectives: The clinical feasibility and potential of curved LiTT trajectories through steerable needles has yet to be investigated. This is the focus of our work. Methods: We propose a GPU-accelerated computer-assisted planning (CAP) algorithm for steerable needle insertions that generates optimized curved 3D trajectories with maximal ablation of the amygdalohippocampal complex and minimal collateral damage to nearby structures, while accounting for a variable ablation diameter ( $5-15$ mm). Results: Simulated trajectories and ablations were performed on 5 patients with mesial temporal sclerosis (MTS), which were identified from a prospectively managed database. The algorithm generated obstacle-free paths with significantly greater target area ablation coverage and lower PHG ablation variance compared to straight line trajectories. Conclusions: The presented CAP algorithm returns increased ablation of the amygdalohippocampal complex, with lower patient risk scores compared to straight-line trajectories. Significance: This is the first clinical application of preoperative planning for steerable needle based LiTT. This study suggests that steerableneedles have the potential to improve LiTT procedure efficacy whilst improving the safety and should thus be investigated further.

Dopaminergic agents are still the mainstay of therapy in Parkinson's disease. Such dopamine replacement therapy results in a reduction in motor symptoms in the early stages of the disease. However, dopaminergic agents will cause motor (motor fluctuations and dyskinesia) and nonmotor (sensory, autonomic, and psychiatric) complications, 50% will occur after 5 years, The operative approach has been shown to be effective in improving motor symptoms in PD. Deep brain stimulation (DBS), which is the second largest finding after levodopa, is still the first choice of operative treatment for PD, however, other operative therapies such as ablative therapy (radiofrequency, stereotactic radiosurgery, focused ultrasound thermal ablation, laser interstitial thermal therapy) have almost the same effectiveness. with DBS. As primary care physicians, it is very important for neurologists to understand the role in operative therapy that is currently developing. Keywords: Parkinson's disease, surgery, neurologist, therapy.

Laser interstitial thermal therapy (LITT) is a minimally invasive neurosurgical technique that has been demonstrated to successfully ablate intracranial tumors. While LITT for supratentorial lesions can often be straightforward, ablation of infratentorial lesions can be difficult with current targeting technologies and instrumentation. The anatomical difficulty of targeting posterior fossa masses can be further complicated in patients who have had a prior craniectomy or other procedure that removed the bone that is required to set the surgical trajectory. This article describes use of a three-dimensional (3D)–printed customized surgical implant to improve and enable targeting of posterior fossa lesions using LITT, particularly in the setting of prior craniectomy. A 3D-printed implant was customized for a patient with a history of metastatic lung cancer and prior posterior fossa craniectomy who presented for treatment of a progressively enlarging contrast-enhancing lesion in the right cerebellar hemisphere. The device included a built-in bolt trajectory for LITT ablation. The temporary implant was successfully fabricated for use with laser ablation of a right cerebellar mass. Three potential trajectories for the LITT bolt were incorporated into the temporary implant, but only the primary trajectory was utilized. Laser ablation was performed with the implant and a SideFire laser probe. Customized 3D-printed implants can enable the use of LITT for patients who would not otherwise be candidates.

Understanding factors that influence technology diffusion is central to clinical translation of novel therapies. We characterized the pattern of adoption for laser interstitial thermal therapy (LITT), also known as stereotactic laser ablation (SLA), in neuro-oncology using the National Inpatient Sample (NIS) database. We identified patients age ≥ 18 in the NIS (2012–2018) with a diagnosis of primary or metastatic brain tumor that underwent LITT or craniotomy. We compared characteristics and outcomes for patients that underwent these procedures. LITT utilization increased ~ 400% relative to craniotomy during the study period. Despite this increase, the total number of LITT procedures performed for brain tumor was 2 comorbidities (OR 0.64, CI95 0.51–0.79) or to be older (OR 0.92, CI95 0.86–0.99) and more likely to be female (OR 1.35, CI95 1.08–1.69), Caucasian compared to Black (OR 1.94, CI95 1.12–3.36), and covered by private insurance compared to Medicare or Medicaid (OR 1.38, CI95 1.09–1.74). LITT hospital stays were 50% shorter than craniotomy (IRR 0.52, CI95 0.45–0.61). However, charges related to the procedures were comparable between LITT and craniotomy ($1397 greater for LITT, CI95 $−5790 to $8584). For neuro-oncology indications, LITT utilization increased ~ 400% relative to craniotomy. Relative to craniotomy-treated patients, LITT-treated patients were likelier to be young, female, non-Black race, covered by private insurance, or with

Background Surgical resection has been shown to prolong survival in patients with glioblastoma multiforme (GBM), although this benefit has not been demonstrated for reoperation following tumor recurrence. Laser interstitial thermal therapy (LITT) is a minimally invasive ablation technique that has been shown to effectively reduce tumor burden in some patients with intracranial malignancy. The aim of this study was to describe the safety and efficacy of LITT for recurrent and newly diagnosed GBM at a large tertiary referral center. Methods Patients with GBM receiving LITT were retrospectively analyzed. Overall survival from the time of LITT was the primary end point measured. Results There were 69 patients identified for inclusion in this study. The median age of the cohort was 56 years (range, 15–77 years). Median tumor volume was 10.4 cm3 (range, 1.0–64.0 cm3). A Kaplan-Meier estimate of median overall survival for the series from the time of LITT was 12 months (95% confidence interval 8–16 months). Median progression-free survival for the cohort from LITT was 4 months (95% confidence interval 3–7 months). Adjuvant chemotherapy significantly prolonged progression-free survival and overall survival (P Conclusions LITT can safely reduce intracranial tumor burden in patients with GBM who have exhausted other adjuvant therapies or are poor candidates for conventional resection techniques.

OBJECTIVECorpus callosotomy is a palliative procedure that is effective at reducing seizure burden in patients with medically refractory epilepsy. The procedure is traditionally performed via open craniotomy with interhemispheric microdissection to divide the corpus callosum. Concerns for morbidity associated with craniotomy can be a deterrent to patients, families, and referring physicians for surgical treatment of epilepsy. Laser interstitial thermal therapy (LITT) is a less invasive procedure that has been widely adopted in neurosurgery for the treatment of tumors. In this study, the authors investigated LITT as a less invasive approach for corpus callosotomy.METHODSThe authors retrospectively reviewed all patients treated for medically refractory epilepsy by corpus callosotomy, either partial or completion, with LITT. Chart records were analyzed to summarize procedural metrics, length of stay, adverse events, seizure outcomes, and time to follow-up. In select cases, resting-state functional MRI was performed to qualitatively support effective functional disconnection of the cerebral hemispheres.RESULTSTen patients underwent 11 LITT procedures. Five patients received an anterior two-thirds LITT callosotomy as their first procedure. One patient returned after LITT partial callosotomy for completion of callosotomy by LITT. The median hospital stay was 2 days (IQR 1.5–3 days), and the mean follow-up time was 1.0 year (range 1 month to 2.86 years). Functional outcomes are similar to those of open callosotomy, with the greatest effect in patients with a significant component of drop attacks in their seizure semiology. One patient achieved an Engel class II outcome after anterior two-thirds callosotomy resulting in only rare seizures at the 18-month follow-up. Four others were in Engel class III and 5 were Engel class IV. Hemorrhage occurred in 1 patient at the time of removal of the laser fiber, which was placed through the bone flap of a prior open partial callosotomy.CONCLUSIONSLITT appears to be a safe and effective means for performing corpus callosotomy. Additional data are needed to confirm equipoise between open craniotomy and LITT for corpus callosotomy.

Laser interstitial thermal therapy (LITT) is gaining popularity in the treatment of both primary and secondary intracranial tumors. The goal of LITT is to deliver thermal energy in a predictable, controlled, and minimally invasive fashion. It can be particularly valuable in patients with recurrent tumors who, due to previous radiation or surgery, may have a potentially higher risk of wound breakdown or infection with repeat craniotomy. Deep-seated lesions that are often inaccessible through open approaches (thalamus, hypothalamus, mesial basal temporal lobe, brainstem) may also be suitable targets. The experience and data published thus far on this modality is limited but growing. This review highlights the use of LITT as a primary treatment method in a variety of intracranial tumors, as well as its application as an adjunct to established surgical techniques.

Laser interstitial thermal therapy (LITT) remains a promising advance in the treatment of primary central nervous system malignancies. As indications for its use continue to expand, there has been growing interest in its ability to induce prolonged blood brain barrier (BBB) permeability through hyperthermia, potentially increasing the effectiveness of current therapeutics including BBB-impermeant agents and immunotherapy platforms. In this review, we highlight the mechanism of hyperthermic BBB disruption and LITT-induced immunogenic cell death in preclinical models and humans. Additionally, we summarize ongoing clinical trials evaluating a combination approach of LITT and immunotherapy, which will likely serve as the basis for future neuro-oncologic treatment paradigms. There is evidence to suggest a highly immunogenic response to laser interstitial thermal therapy through activation of both the innate and adaptive immune response. These mechanisms have been shown to potentiate standard methods of oncologic care. There are only a limited number of clinical trials are ongoing to evaluate the utility of LITT in combination with immunotherapy. LITT continues to be studied as a possible technique to bridge the gap between exciting preclinical results and the limited successes seen in the field of neuro-oncology. Preliminary data suggests a substantial benefit for use of LITT as a combination therapy in several clinical trials. Further investigation is required to determine whether or not this treatment paradigm can translate into long-term durable results for primary intracranial malignancies.

OBJECTIVE Magnetic resonance imaging (MRI)-guided laser interstitial thermal therapy (MRg-LITT) is an alternative to open epilepsy surgery. We assess safety and effectiveness of MRg-LITT for extratemporal lobe epilepsy (ETLE) in patients who are considered less favorable for open resection. METHODS We retrospectively reviewed sequential cases of patients with focal ETLE who underwent MRg-LITT between 2012 and 2019. Epileptogenic zones were determined from standard clinical and imaging data ± stereoelectroencephalography (SEEG). Standard stereotactic techniques, MRI thermometry, and a commercial laser thermal therapy system were used for ablations. Anatomic MRI was used to calculate ablation volumes. Clinical outcomes were determined longitudinally. RESULTS Thirty-five patients with mean epilepsy duration of 21.3 ± 12.2 years underwent MRg-LITT for focal ETLE at a mean age 36.4 ± 12.7 years. A mean 2.59 ± 1.45 trajectories per patient were used to obtain ablation volumes of 8.8 ± 7.5 cm3 . Mean follow-up was 27.3 ± 19.5 months. Of 32 patients with >12 months of follow-up, 17 (53%) achieved good outcomes (Engel class I + II) of whom 14 (44%) were Engel class I. Subgroup analysis revealed better outcomes for patients with lesional ETLE than for those who were nonlesional, multifocal, or who had failed prior interventions (P = .02). Of 13 patients showing favorable seizure-onset patterns (localized low voltage fast activity or rhythmic spiking on SEEG) prior to ablation, 9 (69%) achieved good outcomes, whereas only 3 of 11 (27%) who show other slower onset patterns achieved good outcomes. Minor adverse events included six patients with transient sensorimotor neurologic deficits and four patients with asymptomatic hemorrhages along the fiber tract. Major adverse events included one patient with a brain abscess that required stereotactic drainage and one patient with persistent hypothalamic obesity. Three deaths-two seizure-associated and one suicide-were unrelated to surgical procedures. SIGNIFICANCE MRI-guided laser interstitial thermal therapy (or MRg-LITT) was well-tolerated and yielded good outcomes in a heterogeneous group of ETLE patients. Lesional epilepsy and favorable seizure-onset patterns on SEEG predicted higher likelihoods of success.

BACKGROUND Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) is a minimally invasive procedure that utilizes intraoperative magnetic resonance thermal imaging (MRTI) to generate a thermal damage estimate (TDE) of the ablative area. In select cases, the MRTI contains a signal artifact or defect that distorts the ablative region. No study has attempted to characterize this artifact. OBJECTIVE To characterize MRTI signal the artifact in select cases to better understand its potential relevance and impact on the ablation procedure. METHODS All ablations were performed using the Visualase magnetic resonance imaging-guided laser ablation system (Medtronic). Patients were included if the MRTI contained signal artifact that distorted the ablative region during the first thermal dose delivered. Ablation artifact was quantified using MATLAB version R2018a (Mathworks Inc, Natick, Massachusetts). RESULTS A total of 116 patients undergoing MRgLITT for various surgical indications were examined. MRTI artifact was observed in 37.0% of cases overall. Incidence of artifact was greater at higher powers (P

Background Surgical options for patients with thalamic brain tumors are limited. Traditional surgical resection is associated with a high degree of morbidity and mortality. Laser interstitial thermal therapy (LITT) utilizes a stereotactically placed laser probe to induce thermal damage to tumor tissue. LITT provides a surgical cytoreduction option for this challenging patient population. We present our experience treating thalamic brain tumors with LITT. Objective To describe our experience and outcomes using LITT on patients with thalamic tumors. Methods We analyzed 13 consecutive patients treated with LITT for thalamic tumors from 2012 to 2017. Radiographic, clinical characteristics, and outcome data were collected via review of electronic medical records. Results Thirteen patients with thalamic tumors were treated with LITT. Most had high-grade gliomas, including glioblastoma (n = 9) and anaplastic astrocytoma (n = 2). The average tumor volume was 12.0 cc and shrank by 42.9% at 3 mo. The average hospital stay was 3.0 d. Median ablation coverage as calculated by thermal damage threshold (TDT) lines was 98% and 95% for yellow (>43°C for >2 min) or blue (>10 min), respectively. Median disease-specific progression-free survival calculated for 8 patients in our cohort was 6.1 mo (range: 1.1-15.1 mo). There were 6 patients with perioperative morbidity and 2 perioperative deaths because of intracerebral hematoma. Conclusion LITT is a feasible treatment for patients with thalamic tumors. LITT offers a cytoreduction option in this challenging population. Patient selection is key. Close attention should be paid to lesion size to minimize morbidity. More studies comparing treatment modalities of thalamic tumors need to be performed.

Purpose The aim of this paper is to discuss the current evidence for Laser Interstitial Thermal Therapy (LITT) in the treatment of brain metastases, our current recommendations for patient selection and the future perspectives for this therapy. We have also touched upon the possible complications and role of systemic therapy coupled with LITT for the treatment of brain metastases Material and Methods Two authors carried out the literature search using two databases independently, including PubMed, and Web of Science. The review included prospective and retrospective studies using LITT to treat brain metastases. Results Twenty-two original articles were analyzed in this review, particularly clinical outcomes and complications. We have also provided our institutional experience in the use of LITT to treat brain metastases and addressed future perspectives for the use of this technology. Conclusions The current literature supports LITT as a safe and effective therapy for patients with brain metastases that have failed SRS. Larger studies are still required to better evaluate the use of systemic therapy in concomitance with LITT. New images modalities may enable optimized treatment and outcomes.

Radiation necrosis is a well described complication after radiosurgical treatment of intracranial pathologies - best recognized after the treatment of patients with arteriovenous malformations and brain metastases but possibly also affecting patients treated with radiosurgery for meningioma. The pathophysiology of radiation necrosis is still not well understood but is most likely a secondary local tissue inflammatory response to brain tissue injured by radiation. Radiation necrosis in brain metastases patients may present radiographically and behave clinically like recurrent tumor. Differentiation between radiation necrosis and recurrent tumor has been difficult based on radiographic changes alone. Biopsy or craniotomy therefore remains the gold standard method of diagnosis. For symptomatic patients, corticosteroids are first-line therapy, but patients may fail medical management due to intolerance of chronic steroids or persistence of symptoms. In these cases, open surgical resection has been shown to be successful in management of surgically amenable lesions but may be suboptimal in patients with deep-seated lesions or extensive prior cranial surgical history, both carrying high risk for peri-operative morbidity. Laser interstitial thermal therapy has emerged as a viable, alternative surgical option. In addition to allowing access to tissue for diagnosis, thermal treatment of the lesion can also be delivered precisely and accurately under real-time imaging guidance. This review highlights the pertinent studies that have shaped the impetus for use of laser interstitial thermal therapy in the treatment of radiation necrosis, reviewing indications, outcomes, and nuances toward successful application of this technology in patients with suspected radiation necrosis.

Hyperthermia therapy (HT) of cancer is a well-known treatment approach. With the advent of new technologies, HT approaches are now important for the treatment of brain tumors. We review current clinical applications of HT in neuro-oncology and ongoing preclinical research aiming to advance HT approaches to clinical practice. Laser interstitial thermal therapy (LITT) is currently the most widely utilized thermal ablation approach in clinical practice mainly for the treatment of recurrent or deep-seated tumors in the brain. Magnetic hyperthermia therapy (MHT), which relies on the use of magnetic nanoparticles (MNPs) and alternating magnetic fields (AMFs), is a new quite promising HT treatment approach for brain tumors. Initial MHT clinical studies in combination with fractionated radiation therapy (RT) in patients have been completed in Europe with encouraging results. Another combination treatment with HT that warrants further investigation is immunotherapy. HT approaches for brain tumors will continue to a play an important role in neuro-oncology.

Laser interstitial thermal therapy (LITT) is a novel, minimally invasive alternative to craniotomy, and as with any new technology, comes with a learning curve.We present our experience detailing the evolution of this technology in our practice in one of the largest patient cohorts to date regarding LITT in neuro-oncology.We reviewed 238 consecutive patients with brain tumor treated with LITT at our institution. Data on patient, surgery and tumor characteristics, and follow-up were collected. Patients were categorized into 2 cohorts: early (2014, 100 patients) and recent (2015, 138 patients). Median follow-up for the entire cohort was 8.4 months.The indications for LITT included gliomas (70.2%), radiation necrosis (21.0%), and metastasis (8.8%). Patient demographics stayed consistent between the 2 cohorts, with the exception of age (early, 54.3; recent, 58.4; P = 0.04). Operative time (6.6 vs. 3.5; P0.001) and number of trajectories (53.1% vs. 77.9% with 1 trajectory; P0.001) also decreased in the recent cohort. There was a significant decrease in permanent motor deficits over time (15.5 vs. 4.4%; P = 0.005) and 30-day mortality (4.1% vs. 1.5%) also decreased (not statistically significant) in the recent cohort. In terms of clinical outcomes, poor preoperative Karnofsky Performance Status (≤70) were significantly correlated with increased permanent deficits (P = 0.001) and decreased overall survival (P0.001 for all time points).We observed improvement in operative efficiency and permanent deficits over time and also patients with poor preoperative Karnofsky Performance Status achieved suboptimal outcomes with LITT. As many other treatment modalities, patient selection is important in this procedure.

Corpus callosotomy is a palliative surgical option for patients with refractory epilepsy and frequent drop attacks, decreasing seizure frequency and severity by disconnecting the cerebral hemispheres. Though often successful, open surgery is not without risk. Corpus callosotomy by MRI-guided laser interstitial thermal therapy (MRgLITT) is a minimally invasive alternative to the standard open procedure. This report aims to present an illustrative case and systematically review the current literature on the surgical technique. A systematic review of the English literature through January 2019 was performed. Articles were searched by title utilizing the following key word combinations: “laser” and “callosotomy”, “callosotomy” and “ablation”, “laser” and “corpus”, “callosotomy” and “thermal”, and “stereotactic” and callosotomy”. The articles recovered were then classified by level of evidence and summarized. Fifteen papers were reviewed, of which 6 met inclusion and exclusion criteria. All included studies were classified as level IV evidence. There was a total of 13 patients ranging from 13 months to 44 years old (mean 23.5 years old). The number of laser fibers utilized ranged from 1 to 3. Engel class I was achieved in 5 patients, II in 4, III in 2, IV in 1. Reported patient follow up was 4–39.7 months (mean 15.43). Corpus callosotomy utilizing MRI-guided laser interstitial thermal therapy results in improvement in seizure frequency and severity with minimal complications. Prospective trials are needed to compare its seizure control and long-term outcomes to that of standard open callosotomy.

Background Glioblastoma multiforme (GBM) is an aggressive intracranial malignancy that confers a poor prognosis despite maximum surgical resection and chemoradiotherapy. Survival decreases further with deep-seated lesions. Laser interstitial thermal therapy (LITT) is an emerging minimally invasive technique for tumor ablation shown to reduce tumor burden effectively, particularly in deep-seated locations less amenable to gross total resection. We describe our initial technical experience of using the combination of LITT followed by surgical resection in patients with GBMs that exhibit both an easily accessible and deep-seated component. Materials and Methods Patients with GBM who received concurrent LITT and surgical resection at our institution were identified. Patient demographic and clinical information was procured from the University of Texas MD Anderson Cancer Center electronic medical record along with preoperative, postoperative, and 1-month follow-up magnetic resonance imaging (MRI). Results Four patients (n = 2 male, n = 2 female) with IDH-wild type GBM who received combined LITT and surgical resection were identified and analyzed retrospectively. All patients received chemoradiotherapy before presentation. All but one patient (75%) received resection before presentation. Median age was 54 years (range: 44–56 years). Median length of hospital stay was 6.5 days (range: 2–47 days). Median extent of combined ablation/resection was 90.4%. One of the four patients experienced complications in the perioperative or immediate follow-up periods. Local recurrence was observed in one patient during the follow-up period. Conclusion Malignant gliomas in deep-seated locations or in close proximity to white matter structures are challenging to manage. LITT followed by surgical resection may provide an alternative for tumor debulking that minimizes potential morbidities and extent of residual tumor. Further studies comparing this approach with standard resection techniques are warranted.

BACKGROUND Laser Ablation of Abnormal Neurological Tissue using Robotic NeuroBlate System (LAANTERN) is an ongoing multicenter prospective NeuroBlate (Monteris Medical) LITT (laser interstitial thermal therapy) registry collecting real-world outcomes and quality-of-life (QoL) data. OBJECTIVE To compare 12-mo outcomes from all subjects undergoing LITT for intracranial tumors/neoplasms. METHODS Demographics, intraprocedural data, adverse events, QoL, hospitalizations, health economics, and survival data are collected; standard data management and monitoring occur. RESULTS A total of 14 centers enrolled 223 subjects; the median follow-up was 223 d. There were 119 (53.4%) females and 104 (46.6%) males. The median age was 54.3 yr (range 3-86) and 72.6% had at least 1 baseline comorbidity. The median baseline Karnofsky Performance Score (KPS) was 90. Of the ablated tumors, 131 were primary and 92 were metastatic. Most patients with primary tumors had high-grade gliomas (80.9%). Patients with metastatic cancer had recurrence (50.6%) or radiation necrosis (40%). The median postprocedure hospital stay was 33.4 h (12.7-733.4). The 1-yr estimated survival rate was 73%, and this was not impacted by disease etiology. Patient-reported QoL as assessed by the Functional Assessment of Cancer Therapy-Brain was stabilized postprocedure. KPS declined by an average of 5.7 to 10.5 points postprocedure; however, 50.5% had stabilized/improved KPS at 6 mo. There were no significant differences in KPS or QoL between patients with metastatic vs primary tumors. CONCLUSION Results from the ongoing LAANTERN registry demonstrate that LITT stabilizes and improves QoL from baseline levels in a malignant brain tumor patient population with high rates of comorbidities. Overall survival was better than anticipated for a real-world registry and comparative to published literature., Graphical Abstract Graphical Abstract

Spinal laser interstitial thermotherapy in combination with spinal stereotactic radiosurgery has been developed as a percutaneous minimally invasive approach for the treatment of spinal metastasis. The rational and indications for this hybrid therapy are discussed, along with a brief description of the surgical technique and results. It has been the authors' experience that selected cases of high-grade metastatic epidural spinal cord compression can be effectively treated, achieving durable local control. Lessons learned during the performance of more than 100 cases are reported in addition to future directions for this treatment modality.

Background Laser interstitial thermal therapy (LITT) is a growing technology to treat a variety of brain lesions. It offers an alternative to treatment options, such as open craniotomy and stereotactic radiosurgery. Objective To analyze our experience using LITT for metastatic melanoma. Methods This is a retrospective chart review of the patients from our institution. Our case series involves 5 patients who had previously failed radiation treatment. Results Our patients have low complication rates and short hospital stays. Both are considerably lower when compared to the literature for metastatic melanoma. Conclusion LITT is a safe therapy, with few complications and short hospital stays.

Background For patients with focal drug-resistant epilepsy (DRE), surgical resection of the epileptogenic zone (EZ) may offer seizure freedom and benefits for quality of life. Yet, concerns remain regarding invasiveness, morbidity, and neurocognitive side effects. Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) has emerged as a less invasive option for stereotactic ablation rather than resection of the EZ. Objective To provide an introduction to MRgLITT for epilepsy, including historical development, surgical technique, and role in therapy. Methods The development of MRgLITT is briefly recounted. A systematic review identified reported techniques and indication-specific outcomes of MRgLITT for DRE in human studies regardless of sample size or follow-up duration. Potential advantages and disadvantages compared to available alternatives for each indication are assessed in an unstructured review. Results Techniques and outcomes are reported for mesial temporal lobe epilepsy, hypothalamic hamartoma, focal cortical dysplasia, nonlesional epilepsy, tuberous sclerosis, periventricular nodular heterotopia, cerebral cavernous malformations, poststroke epilepsy, temporal encephalocele, and corpus callosotomy. Conclusion MRgLITT offers access to foci virtually anywhere in the brain with minimal disruption of the overlying cortex and white matter, promising fewer neurological side effects and less surgical morbidity and pain. Compared to other ablative techniques, MRgLITT offers immediate, discrete lesions with real-time monitoring of temperature beyond the fiber tip for damage estimates and off-target injury prevention. Applications of MRgLITT for epilepsy are growing rapidly and, although more evidence of safety and efficacy is needed, there are potential advantages for some patients.

PurposeThe safety and effectiveness of laser interstitial thermal therapy (LITT) relies critically on the ability to continuously monitor the ablation based on real-time temperature mapping using magnetic resonance thermometry (MRT). This technique uses gradient recalled echo (GRE) sequences that are especially sensitive to susceptibility effects from air and blood. LITT for brain tumors is often preceded by a biopsy and is anecdotally associated with artifact during ablation. Thus, we reviewed our experience and describe the qualitative signal dropout that can interfere with ablation.MethodsWe retrospectively reviewed all LITT cases performed in our intraoperative MRI suite for tumors between 2017 and 2020. We identified a total of 17 LITT cases. Cases were reviewed for age, sex, pathology, presence of artifact, operative technique, and presence of blood/air on post-operative scans.ResultsWe identified six cases that were preceded by biopsy, all six had artifact present during ablation, and all six were noted to have air/blood on their post-operative MRI or CT scans. In two of those cases, the artifactual signal dropout qualitatively interfered with thermal damage thresholds at the borders of the tumor. There was no artifact in the 11 non-biopsy cases and no obvious blood or air was noted on the post-ablation scans.ConclusionAdditional consideration should be given to pre-LITT biopsies. The presence of air/blood caused an artifactual signal dropout effect in cases with biopsy that was severe enough to interfere with ablation in a significant number of those cases. Additional studies are needed to identify modifying strategies.

OBJECTIVE Corpus callosotomy is a safe and effective procedure for reducing the frequency of drop attacks. MR-guided laser interstitial thermal therapy (MRgLITT) offers a minimally invasive alternative to conventional open craniotomy for callosotomy. We hypothesized that MRgLITT callosotomy could be safely performed in pediatric patients with similar seizure control. METHODS We present an institutional case series of 11 procedures in 10 patients for the treatment of drop attacks in drug-refractory primary generalized epilepsy. MRgLITT was used for complete callosotomy, anterior two-thirds, posterior, or ablation of residual callosal fibers following prior callosotomy (open or MRgLITT). We retrospectively reviewed clinical course, operative details, radiographic imaging, clinical outcomes, and complications. RESULTS Operative time ranged from 4-8 hours, and median hospitalization was 2 days. No complications were encountered. Among the 7 patients with at least 3 months of follow-up, 71% experienced freedom from drop attacks at longest follow-up and 57% of cases showed improvement in their other seizure semiologies as well (Engel Class II: 28%, Class III: 28%, Class IV: 43%). SIGNIFICANCE MR-guided LITT callosotomy is safe and effective modality in the management of pediatric patients with medically intractable epilepsy characterized by drop attacks. While this is among the largest pediatric series to date, further studies are required to delineate its safety and efficacy among such patients.

Magnetic resonance-guided laser interstitial thermal therapy (MR-gLiTT) is a novel minimally invasive treatment approach for drug-resistant focal epilepsy and brain tumors. Using thermal ablation induced by a laser diode implanted intracranially in a stereotactic manner, the technique is highly effective and safe, reducing the risk associated with more traditional open surgical approaches that could lead to increased neurological morbidity. Indications for MR-gLiTT in pediatric epilepsy surgery include hypothalamic hamartoma, tuberous sclerosis complex, cavernoma-related epilepsy, SEEG-guided seizure onset zone ablation, corpus callosotomy, periventricular nodular heterotopia, mesial temporal lobe epilepsy, and insular epilepsy. We review the available literature on the topic and present our series of patients with drug-resistant epilepsy treated by MR-gLiTT. Our experience, represented by six cases of hypothalamic hamartomas, one case of tuberous sclerosis, and one case of dysembryoplastic neuroepithelial tumor, helps to confirm that MR-gLiTT is a highly safe and effective procedure for several epilepsy conditions in children.

BACKGROUND: Laser interstitial thermal therapy (LITT) under magnetic resonance imaging (MRI) monitoring is being increasingly used in cytoreductive surgery of recurrent brain tumors and tumors located in eloquent brain areas. The objective of this study was to adapt this technique to an animal glioma model. METHODS: A rat model of U251 glioblastoma (GBM) was employed. Tumor location and extent were determined by MRI and dynamic contrast-enhanced (DCE) MRI. A day after assessing tumor appearance, tumors were ablated during diffusion-weighted imaging (DWI)-MRI using a Visualase LITT system (n=5). Brain images were obtained immediately after ablation and again at 24 h post-ablation to confirm the efficacy of tumor cytoablation. Untreated tumors served as controls (n=3). Rats were injected with fluorescent isothiocyanate (FITC) dextran and Evans blue that circulated for 10 min after post-LITT MRI. The brains were then removed for fluorescence microscopy and histopathology evaluations using hematoxylin and eosin (H&E) and major histocompatibility complex (MHC) staining. RESULTS: All rats showed a space-occupying tumor with T2 and T1 contrast-enhancement at pre-LITT imaging. The rats that underwent the LITT procedure showed a well demarcated ablation zone with near-complete ablation of tumor tissue and with peri-ablation contrast enhancement at 24 h post-ablation. Tumor cytoreduction by ablation as seen on MRI was confirmed by H&E and MHC staining. CONCLUSIONS: Data showed that tumor cytoablation using MRI-monitored LITT was possible in pre-clinical glioma models. Real-time MRI monitoring facilitated visualizing and controlling the area of ablation as it is otherwise performed in clinical applications.

OPINION STATEMENT Laser interstitial thermal therapy (LITT) is a minimally invasive treatment option for brain tumors including glioblastoma, other primary central nervous system (CNS) neoplasms, metastases, and radiation necrosis. LITT employs a fiber optic coupled laser delivery probe stabilized via stereotaxis to deliver thermal energy that induces coagulative necrosis in tumors to achieve effective cytoreduction. LITT complements surgical resection, radiation treatment, tumor treating fields, and systemic therapy, especially in patients who are high risk for surgical resection due to tumor location in eloquent regions or poor functional status. These factors must be balanced with the increased rate of cerebral edema post LITT compared to surgical resection. LITT has also been shown to induce transient disruption of the blood-brain barrier (BBB), especially in the peritumoral region, which allows for enhanced CNS delivery of anti-neoplastic agents, thus greatly expanding the armamentarium against brain tumors to include highly effective anti-neoplastic agents that have poor BBB penetration. In addition, hyperthermia-induced immunogenic cell death is another secondary side effect of LITT that opens up immunotherapy as an attractive adjuvant treatment for brain tumors. Numerous large studies have demonstrated the safety and efficacy of LITT against various CNS tumors and as the literature continues to grow on this novel technique so will its indications.

Background Hypothalamic hamartomas (HH) are a challenging pathology that cause gelastic seizures. Magnetic Resonance Imaging-guided Laser Interstitial Thermal Therapy (MRgLITT) offers a safe and effective treatment for HHs via a minimally invasive technique. Objective To determine how clinical outcome correlates to residual tumor volume and surgical strategy by analyzing radiographic data and reconstructing volumetric imaging. Methods Clinical and radiographic information of 58 pediatric patients who underwent MRgLITT for HH with at least 6 mo of follow-up were retrospectively reviewed. MR imaging was volumetrically reconstructed to analyze the impact of hamartoma and ablation volumes on outcome. Primary outcome measure was freedom from gelastic seizures. Results Eighty-one percent of patients were completely free of gelastic seizures at last follow-up; of 22 patients with secondary nongelastic epilepsy, 15 were free of additional seizures. Postoperative complication rate was low. There was no significant difference in gelastic seizure outcome related to pre- or postoperative hamartoma size. Residual hamartoma percentage in those free of gelastic seizures was 43% compared to 71% in those with continued seizures (P = .021). Larger hamartomas required multiple ablations to achieve seizure freedom. Conclusion This large series of patients confirms the safety and efficacy of MRgLITT for pediatric HH and describes morphological considerations that predict success. Our data suggest that complete ablation of the lesion is not necessary, and that the focus should be on appropriate disconnection of the epileptogenic network. We have found that a staged approach to hamartoma ablation allows adequate disconnection of the hamartoma while mitigating risk to surrounding structures.

Background Posterior fossa tumors are rare in adults and pose a challenge to treat due to the bony contour of the posterior fossa, complex anatomical structures including deep venous sinuses, and the proximity of the fourth ventricle and brain stem. We describe our experience with laser interstitial thermal therapy (LITT) for the management of brain metastases and radiation necrosis of the posterior fossa. Methods We retrospectively analyzed 13 patients with metastases and radiation necrosis of the posterior fossa managed with LITT. Results Thirteen patients with histopathologically confirmed radiation necrosis (n = 5) and metastases (n = 8) of the posterior fossa underwent LITT. The median preoperative tumor was 4.66 cm3, and median postoperative ablation cavity volume was 6.29 cm3. The median volume of the ablation cavity was decreased to 2.90 cm3 at a 9-month follow-up. The median volume of peritumoral edema was 12.25 cm3, which fell to a median of 5.77 cm3 at 1-month follow-up. The median progression-free survival was 7 months (range, 3–14 months) and the mean overall survival was 40 months (range, 2–49 months) after LITT. There were no intraoperative complications. One patient experienced palsy of the seventh and eighth cranial nerves on follow-up, attributable to LITT. Conclusions Lesions of the posterior fossa are challenging to treat given their proximity to the dura and venous sinuses. Our findings demonstrate that LITT ablation may be a safe and feasible option for metastases and radiation necrosis of the posterior fossa. Larger studies are needed to confirm the efficacy of this approach.

Introduction Laser interstitial thermal therapy (LITT) is a novel minimally invasive alternative to open mesial temporal resection in drug-resistant mesial temporal lobe epilepsy (MTLE). The safety and efficacy of the procedure are dependent on the pre-planned trajectory and the extent of the ablation achieved. Ablation of the mesial hippocampal head has been suggested to be an independent predictor of seizure freedom, whilst sparing of collateral structures is thought to result in improved neuropsychological outcomes. We aim to validate an automated trajectory planning platform against manually planned trajectories to objectively standardize the process. Methods Using the EpiNav™ platform we compare automated trajectory planning parameters derived from expert opinion and machine learning to undertake a multicentre validation study against manually planned and implemented trajectories in 95 patients with MTLE. We estimate ablation volumes of regions of interest and quantify the size of the avascular corridor through the use of a risk score as a marker of safety. We also undertake blinded external expert feasibility ratings and preference rankings between the trajectories. Results Automated trajectory planning employs a complex algorithm to optimize planning parameters in order to maximize ablation of the mesial hippocampal head and amygdala, whilst sparing the parahippocampal gyrus. Automated trajectories resulted in significantly lower risk scores and greater amygdala ablation percentage, whilst overall hippocampal ablation percentage did not differ significantly. Blinded external expert raters were significantly more likely to give preference to automated compared to manually planned trajectories. Conclusion Retrospective studies of automated trajectory planning show much promise in optimizing safety parameters and ablation volumes during LITT for MTLE. Multi-center validation provides evidence that the algorithm is robust and blinded external expert ratings indicate that the trajectories are clinically feasible. Prospective validation studies are now required to determine if automated trajectories result in improved seizure freedom rates and reduced neuropsychological deficits.

Introduction:Many different types of surgical procedures are available for patients with drug-resistant epilepsy. MRI-guided laser interstitial thermal therapy is a stereotactic procedure with the potential to provide excellent seizure outcomes, while minimizing surgical approach related complications.Areas covered:This review will cover the role of MRgLITT in the treatment of multiple facets of epilepsy including temporal lobe epilepsy, nodular heterotopias, hypothalamic hamartomas, as well as corpus Callosotomy.Expert opinion:The development of magnetic resonance thermography has advanced continuous monitoring of thermal tissue destruction of pathological tissue in near real-time to allow for individualized neurological care for a person with epilepsy. Overall the results of MRgLITT appear similar to larger open forms of epilepsy surgery though with the promise of a safer side-effect profile. To improve this technique we must develop intraoperative biomarkers of procedural success, and develop tools to improve our patient selection.

The optimal treatment of brain metastases recurring after radiosurgery (BMRS) remains an area of active investigation. Stereotactic laser ablation (SLA, also known as laser interstitial thermal therapy) has recently emerged as a potential treatment option.To summarize the available literature on SLA as treatment of BMRS and synthesize findings on local control, overall survival, neurologic outcome, imaging findings, morbidity, and postprocedure clinical course.We performed a comprehensive search of PubMed for articles investigating SLA as treatment of BMRS.Thirteen peer-reviewed publications met our search criteria. Local control was a function of the percentage of tumor that was thermally ablated. In completely ablated tumors, 3-month local control was 80%-100%. Median survival ranged from 5.8 to 19.8 months. About two-thirds of treated lesions showed postablation expansion of contrast-enhancing volume and fluid-attenuated inversion recovery volume. Expansion could start within an hour of treatment, and resolution typically occurred within 6 months. Notably, maximal expanded contrast-enhancing volume could reach3-fold the preoperative lesion volume. The incidence of SLA-related permanent neurologic injuries was10%. The most common complications were hemorrhage, thermal injury causing neurologic deficit, and malignant cerebral edema. Nearly all patients were treated with dexamethasone, but there was variability in the dose and duration of therapy. Median hospital stay was 1-2 days (range, 1-5 days), and most treated patients were discharged home (range, 59.5%-100%).Our analysis provides support for continued development of SLA as a treatment of BMRS. Standardization of periprocedural management will be needed.

Laser interstitial thermal therapy (LITT) is a novel MR thermometry-guided thermoablative tool revolutionizing the clinical management of brain tumors. A limitation of LITT is our inability to estimate a priori how tissues will respond to thermal energy, which hinders treatment planning and delivery. The aim of this study was to determine whether brain tumor LITT ablation dynamics may be predicted by features of the preoperative MRI and the relevance of these data, if any, to the recurrence of metastases after LITT. Intraoperative thermal damage estimate (TDE) map pixels representative of irreversible damage were retrospectively quantified relative to ablation onset for 101 LITT procedures. Raw TDE pixel counts and TDE pixel counts modelled with first order dynamics were related to eleven independent variables derived from the preoperative MRI, demographics, laser settings, and tumor pathology. Stepwise regression analysis generated predictive models of LITT dynamics, and leave-one-out cross validation evaluated the accuracy of these models at predicting TDE pixel counts solely from the independent variables. Using a deformable atlas, TDE maps were co-registered to the immediate post-ablation MRI, allowing comparison of predicted and actual ablation sizes. Brain tumor TDE pixel counts modelled with first order dynamics, but not raw pixel counts, are correlated with the independent variables. Independent variables showing strong relations to the TDE pixel measures include T1 gadolinium and T2 signal, perfusion, and laser power. Associations with tissue histopathology are minimal. Leave-one-out analysis demonstrates that predictive models using these independent variables account for 77% of the variance observed in TDE pixel counts. Analysis of metastases treated revealed a trend towards the over-estimation of LITT effects by TDE maps during rapid ablations, which was associated with tumor recurrence. Features of the preoperative MRI are predictive of LITT ablation dynamics and could eventually be used to improve the clinical efficacy with which LITT is delivered to brain tumors.

Background and importance Low-grade insular gliomas remain challenging tumors for aggressive resection because of the numerous functional and vascular structures surrounding them. Because of the potential morbidities associated with open surgical resection, less invasive techniques may confer a more optimal balance between cytoreduction and surgical complications. For this reason, we evaluated the use of laser interstitial thermal therapy (LITT) for resection of a dominant hemisphere oligodendroglioma World Health Organization (WHO) grade II in a 68-yr-old patient by use of multiple staged surgeries for its resection. Clinical presentation Patient KK was a 68-yr-old female who was found to have a large, left-sided insular mass that was shown to be an oligodendroglioma WHO grade II, positive for codeletion 1p/19q and IDH1 mutant on biopsy. Over the course of 3 mo, KK underwent 2 stages of LITT, targeting different areas of the 5-cm tumor. The 60-d magnetic resonance imaging (MRI) demonstrated a reduction in size of the tumor from 5.2 × 3.3 × 2.4 cm to 3.6 × 1.9 × 1.4 cm. She returned for a second stage targeting the anterior portion of the tumor. KK did well postoperatively and went on to postsurgical chemoradiation. At the 2-yr follow-up, the lesion showed near resolution on MRI. Conclusion This case report demonstrates successful use of LITT for staged surgeries to treat a left hemisphere-dominant insular lesion. This establishes the use of LITT as a viable, minimally invasive option to treat tumors that are difficult to access or pose concerns for increased morbidity through an open surgery.

Corpus callosotomy has been used as a form of surgical palliation for patients suffering from medically refractory generalized seizures, including drop attacks. Callosotomy has traditionally been described as involving a craniotomy with microdissection. MR-guided laser interstitial thermal therapy (MRg-LITT) has recently been used as a minimally invasive method for performing surgical ablation of epileptogenic foci and corpus callosotomy. The authors present 3 cases in which MRg-LITT was used to perform a corpus callosotomy as part of a staged surgical procedure for a patient with multiple seizure types and in instances when further ablation of residual corpus callosum is necessary after a prior open surgical procedure. To the authors’ knowledge, this is the first case series of corpus callosotomy performed using the MRg-LITT system with a 3.3-year average follow-up. Although MRg-LITT is not expected to replace the traditional corpus callosotomy in all cases, it is a safe, effective, and durable alternative to the traditional open corpus callosotomy, particularly in the setting of a prior craniotomy.

OBJECTIVELaser Ablation After Stereotactic Radiosurgery (LAASR) is a multicenter prospective study of laser interstitial thermal (LITT) ablation in patients with radiographic progression after stereotactic radiosurgery for brain metastases.METHODSPatients with a Karnofsky Performance Scale (KPS) score ≥ 60, an age > 18 years, and surgical eligibility were included in this study. The primary outcome was local progression-free survival (PFS) assessed using the Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) criteria. Secondary outcomes were overall survival (OS), procedure safety, neurocognitive function, and quality of life.RESULTSForty-two patients—19 with biopsy-proven radiation necrosis, 20 with recurrent tumor, and 3 with no diagnosis—were enrolled. The median age was 60 years, 64% of the subjects were female, and the median baseline KPS score was 85. Mean lesion volume was 6.4 cm3 (range 0.4–38.6 cm3). There was no significant difference in length of stay between the recurrent tumor and radiation necrosis patients (median 2.3 vs 1.7 days, respectively). Progression-free survival and OS rates were 74% (20/27) and 72%, respectively, at 26 weeks. Thirty percent of subjects were able to stop or reduce steroid usage by 12 weeks after surgery. Median KPS score, quality of life, and neurocognitive results did not change significantly for either group over the duration of survival. Adverse events were also similar for the two groups, with no significant difference in the overall event rate. There was a 12-week PFS and OS advantage for the radiation necrosis patients compared with the recurrent tumor or tumor progression patients.CONCLUSIONSIn this study, in which enrolled patients had few alternative options for salvage treatment, LITT ablation stabilized the KPS score, preserved quality of life and cognition, had a steroid-sparing effect, and was performed safely in the majority of cases.Clinical trial registration no.: NCT01651078 (clinicaltrials.gov)

To investigate the safety and efficacy of stereoelectroencephalography (sEEG) directed magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) in medically refractory insular epilepsy in pediatric patients, define the relationship between ablation volumes and seizure control, and analyze the relationship between thermal energy and ablation volumes. A single-institution, retrospective review of pediatric patients with insular epilepsy who underwent sEEG directed MRgLITT over a 10-month period was performed. Perioperative, imaging, and outcome data were analyzed. Seizure outcomes were determined based on Engel score (Engel I versus Engel II–IV). Insula and ablation volumes were measured, and the proportion of insula volume ablated was calculated. Thermal energy was calculated in joules. Four patients underwent sEEG directed MRgLITT of insular epileptogenic foci. The ablation volume was higher in patients with Engel I outcome (3.93 cm3) compared to Engel II–IV outcome (1.02 cm3). The proportion of ablation to insula volume was lowest in patients with Engel II–IV outcome (25.09%). The mean energy requirement to create a unit volume of ablation in the insula is 1205.86 J. A linear trend was noted between thermal ablation energy and ablation volume (R2 = 0.884). Over a mean follow-up period of 104 days, three patients were seizure-free (Engel I), and one patient saw significant improvement in seizure frequency (Engel III). The proportion of insula ablated, as well as the volume of ablation, are related to seizure outcome with increasing ablation volumes corresponding to improved seizure control. Further analysis of insula laser ablation thermal dynamics and volumes is needed.

Cortical tubers associated with tuberous sclerosis complex (TSC) are potential epileptic foci that are often amenable to resective or ablative surgeries, and controlling seizures at a younger age may lead to improved functional outcomes. MRI-guided laser interstitial thermal therapy (MRgLITT) has become a popular minimally invasive alternative to traditional craniotomy. Benefits of MRgLITT include the ability to monitor the ablation in real time, a smaller incision, shorter hospital stay, reduced blood loss, and reduced postoperative pain. To place the laser probe for LITT, however, stereotaxy is required—which classically involves head fixation with cranial pins. This creates a relative minimum age limit of 2 years old because it demands a mature skull and fused cranial sutures. A novel technique is presented for the application of MRgLITT in a 6-month-old infant for the treatment of epilepsy associated with TSC. To the authors’ knowledge this is the youngest patient treated with laser ablation. The authors used a frameless navigation technique with a miniframe tripod system and intraoperative reference points. This technique expands the application of MRgLITT to younger patients, which may lead to safer surgical interventions and improved outcomes for these children.

Objective To evaluate EEG abnormalities, particularly development of temporal intermittent rhythmic delta activity (TIRDA) after laser interstitial thermal therapy (LITT) and assess the role of further surgery after LITT. Methods We retrospectively identified consecutive cases of LITT for the prevalence of post-operative TIRDA. We assessed baseline demographics, clinical variables including age of seizure onset, age at surgery, pre-operative and post-operative EEG changes. Results 40 patients underwent LITT for drug-resistant temporal lobe epilepsy (TLE), 29 met inclusion criteria. Median duration of follow-up was 15 months. Ten patients had post-LITT ipsilateral TIRDA, another two demonstrated post-operative TIRDA but they occurred contralateral to the side of ablation. None of the patients with TIRDA on their post-LITT EEG became seizure-free. Six out of 29 patients (21%) eventually required anterior temporal lobectomy (ATL), and of those 6 patients 4 (66%) had evidence of TIRDA on their post-LITT follow up EEG. The sensitivity and specificity of post-LITT TIRDA in predicting surgical failure was 57.14% and 100% respectively. Conclusions Post-LITT TIRDA may serve as a biomarker to predict unsuccessful seizure outcome following LITT and be an early indicator for ATL. Significance The presence of TIRDA following LITT should prompt early consideration for reoperation.

Objective Recurrent meningiomas can prove problematic for treatment, especially if anaplastic, as options are limited primarily to surgery and radiation therapy. Laser interstitial thermal therapy (LITT) is a minimally invasive technique for achieving immediate cytoreduction. This study seeks to determine the utility of LITT in the setting of recurrent meningiomas. Materials and methods Patients undergoing LITT for tumor treatment at our institution between November 2014 and February 2016 were identified. Those with biopsy-confirmed meningiomas were reviewed with attention to ablation volume, survival, demographic data, and complications. Data from imaging performed at set intervals post-operatively were available for all. Results Four patients were identified, three of whom had successful treatment with a total of four ablations. The one case that did not result in a successful ablation was due to problems with stereotactic placing of the laser catheter. One patient had a grade 1 meningioma, with the other two being Grade 3. Immediate ablation volumes averaged 75% of preoperative tumor volume and increased to 97% at 2 weeks before dropping to 65% at 3 months. One patient had acute hemiparesis with speech difficulty, which resolved after 6 months. At date of last follow-up, two of three had progression at an average of nine weeks, and one had no progression at 28 weeks. Conclusion LITT appeared to be a potentially viable treatment for recurrent meningiomas. Ablation volumes increased over time, but not beyond the initial meningioma volume. Larger studies are needed to better determine complications and outcomes. Lasers Surg. Med. 51:245-250, 2019. © 2018 Wiley Periodicals, Inc.

BACKGROUND Magnetic resonance imaging (MRI)-guided laser interstitial thermal therapy (MRgLITT) has been used successfully to treat epileptogenic cortical cerebral cavernous malformations (CCM). It is unclear whether MRgLITT would be as feasible or safe for deep CCMs. OBJECTIVE To describe our experience with MRgLITT for symptomatic deep CCMs. METHODS Patients' records were reviewed retrospectively. MRgLITT was carried out using a commercially available system in an interventional MRI suite with efforts to protect adjacent brain structures. Immediate postoperative imaging was used to judge ablation adequacy. Delayed postoperative MRI was used to measure lesion volume changes during follow-up. RESULTS Four patients with CCM in the thalamus, putamen, midbrain, or subthalamus presented with persistent and disabling neurological symptoms. A total of 2 patients presented with disabling headaches and sensory disturbances and 2 with recurrent symptomatic hemorrhages, of which 1 had familial CCM. Patients were considered by vascular neurosurgeons to be poor candidates for open surgery or had refused it. Multiple trajectories were used in most cases. Adverse events included device malfunction with leakage of saline causing transient mass effect in one patient, and asymptomatic tract hemorrhage in another. One patient suffered an expected mild but persistent exacerbation of baseline deficits. All patients showed improvement from a previously aggressive clinical course with lesion volume decreased by 20% to 73% in follow-up. CONCLUSION MRgLITT is feasible in the treatment of symptomatic deep CCM but may carry a high risk of complications without the benefit of definitive resection. We recommend cautious patient selection, low laser power settings, and conservative temperature monitoring in surrounding brain parenchyma.

BACKGROUND Commercial magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) systems utilize a generalized Arrhenius model to estimate the area of tissue damage based on the power and time of ablation. However, the reliability of these estimates in Vivo remains unclear. OBJECTIVE To determine the accuracy and precision of the thermal damage estimate (TDE) calculated by commercially available MRgLITT systems using the generalized Arrhenius model. METHODS A single-center retrospective review of pediatric patients undergoing MRgLITT for lesional epilepsy was performed. The area of each lesion was measured on both TDE and intraoperative postablation, postcontrast T1 magnetic resonance images using ImageJ. Lesions requiring multiple ablations were excluded. The strength of the correlation between TDE and postlesioning measurements was assessed via linear regression. RESULTS A total of 32 lesions were identified in 19 patients. After exclusion, 13 pairs were available for analysis. Linear regression demonstrated a strong correlation between estimated and actual ablation areas (R2 = .97, P

Background: Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. Management includes surgical resection followed by chemoradiation, and prognosis remains poor. Surgical resection is not possible for some deep-seated or eloquent tumors. Laser interstitial thermal therapy (LITT) has emerged as a new, minimally invasive surgical option for deep-seated GBM. Case Description: We report a case of newly diagnosed thalamic GBM managed with LITT followed by radiation and chemotherapy. Conclusion: The patient remains well at 50-month post-LITT, indicating a potentially unique durability of LITT treatment in GBM.

Background Various strategies have been proposed for the treatment of gelastic seizures due to hypothalamic hamartomas (HH), advancing from surgical removal techniques toward functional disconnection strategies. One of the most recent procedure is the Magnetic Resonance guided Laser Interstitial Thermal Therapy (MRg-LITT), which has progressively proved to be a safe and effective technique for hamartomas ablation. In this paper, the authors' preliminary experience with the first two patients treated with this technique in Italy is presented, in order to underline the feasibility of a pure non robotized frameless technique (FS MRg-LITT) while confirming the procedure effectiveness on seizure control. Methods Patients undergoing FS MRg-LITT for the treatment of HH related gelastic seizures since January 2020 were included. A two steps procedure was performed by using the neuronavigation system to define the entry point, the trajectories and to assess the accuracy. Visualase Laser Ablation System was then used for the MR guided ablation of the HH. A multidisciplinary (neurosurgeons, epileptologist, neuroradiologist) institutional board evaluated the patients both in the perioperative period and during follow up. Results A total number of 2 pediatric patients were described. The mean operative time resulted to be 6 hours while the mean accuracy was 0.4 mm. No peri-operative complications were reported. The mean length of stay was 4 days. Lastly, at 1-year follow up both patients resulted to be seizure free and endocrinological functions were preserved. Conclusions FS MRg-LITT for the treatment of HH-related epilepsy could represent an effective technique, being able to guarantee adequate level of accuracy and potentially extending the accessibility of MRg-LITT by lowering its costs and simplifying the overall procedure.

Background and purpose Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) is a minimally invasive procedure that produces real-time thermal damage estimates (TDEs) of ablation. Currently, MRgLITT software provides limited quantitative parameters for intraoperative monitoring, but orthogonal TDE-MRI slices can be utilized to mathematically estimate ablation volume. The objective of this study was to model TDE volumes and validate using post-24 hours MRI ablative volumes. Methods Ablations were performed with the Visualase Laser Ablation System (Medtronic). Using ellipsoidal parameters determined for dual-TDEs from orthogonal MRI planes, TDE volumes were calculated by two definite integral methods (A and B) implemented in Matlab (MathWorks). Post-24 hours MRI ablative volumes were measured in OsiriX (Pixmeo) by two-blinded raters and compared to TDE volumes via paired t-test and Pearson's correlations. Results Twenty-two ablations for 20 patients with various intracranial pathologies were included. Average TDE volume calculated with method A was 3.44 ± 1.96 cm3 and with method B was 4.83 ± 1.53 cm3 . Method A TDE volumes were significantly different than post-24 hours volumes (P Conclusion We present a viable mathematical method integrating dual-plane TDEs to calculate volumes. Future algorithmic iterations will incorporate additional calculated variables that improve ablative volume estimations.

Background Magnetic resonance imaging (MRI)-guided laser interstitial thermal therapy (LITT) is a minimally invasive treatment modality that has been gaining traction in neuro-oncology. Laser ablation is a particularly appealing treatment option when eloquent neurologic function at the tumor location precludes conventional surgical excision. Although typically performed under general anesthesia, LITT in awake patients may help monitor and preserve critical neurologic functions. Objective To describe intraoperative workflow and clinical outcomes in patients undergoing awake laser ablation of brain tumors. Methods We present a cohort of six patients with tumors located in eloquent brain areas that were treated with awake LITT and report three different workflow paradigms involving diagnostic or intraoperative MRI. In all cases, we used NeuroBlate® (Monteris Medical, Plymouth, MN) fiberoptic laser probes for stereotactic laser ablation of tumors. The neurologic status of patients was intermittently assessed every few minutes during the ablation. Results The mean preoperative tumor volume that was targeted was 12.09 ± 3.20 cm3, and the estimated ablation volume was 12.06 ± 2.75 cm3. Performing the procedure in awake patients allowed us close monitoring of neurologic function intraoperatively. There were no surgical complications. The length of stay was one day for all patients except one. Three patients experienced acute or delayed worsening of pre-existing neurologic deficits that responded to corticosteroids. Conclusion We propose that awake LITT is a safe approach when tumors in eloquent brain areas are considered for laser ablation.