Guided Laser Interstitial Thermal Therapy Research Articles

Temporo-Parieto-Occipital Disconnection by Robot-Assisted Magnetic Resonance Imaging–Guided Laser Interstitial Thermal Therapy for Refractory Epilepsy in a Pediatric Patient: Proof-of-Principle Case Report and Surgical Nuances

Magnetic resonance imaging-guided laser interstitial thermal therapy (MRIgLITT) has been proven safe and effective for the treatment of focal epilepsy of different etiologies. It has also been used to disconnect brain tissue in more extensive or diffuse epilepsy, such as corpus callosotomy and hemispherotomy. In this study, we report a case of temporo-parieto-occipital disconnection (TPO) surgery performed using MRIgLITT assisted by a robotic arm for refractory epilepsy of the posterior quadrant. A highly realistic cadaver simulation was performed before the actual surgery. The patient was a 14-year-old boy whose seizures began at the age of eight. The epilepsy was a result of a left perinatal ischemic event that caused a porencephalic cyst, and despite receiving multiple antiepileptic drugs, the patient continued to experience daily seizures which led to the recommendation of surgery. A Wada test lateralized language in the right hemisphere. Motor and sensory function was confirmed in the left hemisphere through MRI functional studies and NexStim®. The left MRIgLITT TPO disconnection was achieved using five laser fibers. The patient followed an excellent postoperative course and was seizure-free, with no additional neurological deficits 24 months after the surgery.

The changing landscape of palliative epilepsy surgery for Lennox Gastaut Syndrome.

Lennox Gastaut Syndrome (LGS) is characterized by drug-resistant epilepsy that typically leads to decreased quality of life and deleterious neurodevelopmental comorbidities from medically refractory seizures. In recent years there has been a dramatic increase in the development and availability of novel treatment strategies for Lennox Gastaut Syndrome patient to improve seizure. Recent advances in neuromodulation and minimally invasive magnetic resonance guided laser interstitial thermal therapy (MRgLITT) have paved the way for new treatments strategies including deep brain stimulation (DBS), responsive neurostimulation (RNS), and MRgLITT corpus callosum ablation. These new strategies offer hope for children with drug-resistant generalized epilepsies, but important questions remain about the safety and effectiveness of these new approaches. In this review, we describe the opportunities presented by these new strategies and how each treatment strategy is currently being employed. Next, we will critically assess available evidence for these new approaches compared to traditional palliative epilepsy surgery approaches, such as vagus nerve stimulation (VNS) and open microsurgical corpus callosotomy (CC). Finally, we will describe future directions that would help define which of the available strategies should be employed and when.

Magnetic Resonance–Guided Laser Interstitial Thermal Therapy for Recurrent Glioblastoma and Radiation Necrosis: A Single-Surgeon Case Series

Evaluate long-term clinical outcomes among patients treated with laser interstitial thermal therapy (LITT) for predicted recurrent glioblastoma (rGBM). Patients with rGBM treated by LITT by a single surgeon (2013-2020) were evaluated for progression-free survival (PFS), overall survival (OS), and OS after LITT. Forty-nine patients (33 men, 16 women; mean [SD] age at diagnosis, 58.7 [12.5] years) were evaluated. Among patients with genetic data, 6 of 34 (18%) had IDH-1 R132 mutations, and 7 of 21 (33%) had MGMT methylation. Patients underwent LITT at a mean (SD) 23.8 (23.8) months after original diagnosis. Twenty of 49 (40%) had previous stereotactic radiosurgery, 37 (75%) intensity-modulated radiation therapy, and 49 (100%) chemotherapy. Patients had a mean 1.2 (0.7) previous resections before LITT. Mean preoperative enhancing and T2 FLAIR volumes were 13.1 (12.8) cm3 and 35.0 (32.8) cm3, respectively. Intraoperative biopsies confirmed rGBM in 31 (63%) and radiation necrosis in 18 (37%). Six perioperative complications occurred: 3 (6%) cases of worsening aphasia, 1 (2%) seizure, 1 (2%) epidural hematoma, and 1 (2%) intraparenchymal hemorrhage. For the rGBM group, median PFS was 2.0 (IQR, 4.0) months, median OS was 20.0 (IQR, 29.5) months, and median OS after LITT was 6.0 (IQR, 10.5) months. For the radiation necrosis group, median PFS was 4.0 (IQR, 4.5) months, median OS was 37.0 (IQR, 58.0) months, and median OS after LITT was 8.0 (IQR, 23.5) months. In a diverse rGBM cohort, LITT was associated with a short duration of posttreatment PFS.

Comparison of magnetic resonance-guided laser interstitial thermal therapy corpus callosum ablation to open microsurgical corpus callosotomy: A single-center retrospective cohort study.

Corpus callosotomy (CC) is an important treatment for atonic seizures in patients with generalized or multifocal drug-resistant epilepsy (DRE). Traditionally, CC is performed via an open microsurgical approach, but more recently, MR-guided stereotactic laser interstitial thermal therapy (LITT) corpus callosum ablation (CCA) has been developed to leverage the safety and minimally invasive nature of LITT. Given the recent adoption of CCA at select centers, how CCA compares to CC is unknown. We aim to compare the clinical seizure outcomes of CCA and CC after extended follow-up. We performed a retrospective cohort study to compare the effectiveness and safety of CC to CCA from 1994 to 2022. The primary outcome was a 50% reduction in target seizure. Secondary outcome measures were postoperative length of stay, adverse events, and other effectiveness metrics. Comparative statistics were executed using Stata. Normality for continuous variables was assessed, and parametric statistics were utilized as needed. Frequency was compared with chi-squared or Fischer's exact tests, when applicable. Data from 47 operations performed on 36 patients were included in this study, of which 13 (36%) patients underwent 17 CCA. Patients who received CCA had similar rates of meaningful reduction (>50%) of atonic seizures as their CC counterparts (55% vs 70% P = 0.15). Patients undergoing CCA had significantly shorter hospitalizations than those receiving CC (2.5 vs 6.0 days P < 0.001). There was no significant difference in rates of postoperative complications between the groups, although the magnitude of the complication rates was lower in the CCA cohort (12% vs 28%). This early experience suggests CCA has similar outcomes to traditional CC, albeit with a shorter hospital stay. However, future studies are necessary to investigate the noninferiority between these two approaches. Large multicenter studies are necessary to investigate differences in adverse events and whether these findings generalize across other centers.

MODL-14. IMAGING, HISTOLOGICAL AND MOLECULAR CHARACTERIZATION AND COMPARISON OF POST-ABLATION RECURRENT TUMOR WITH THE PRIMARY TUMOR IN A PRECLINICAL GLIOBLASTOMA MODEL

Abstract Recurrent glioblastoma (rGBM) is highly aggressive and invasive. A reliable preclinical model that recapitulates these features is not presently available. The objective was to generate a preclinical rGBM model, characterize and compare its imaging, histological and molecular signatures in comparison to the primary tumor. Immune-suppressed, RNU/RNU female rats were implanted with U251N tumor cells in one brain hemisphere (n=33). Tumor progression in all rats was followed by longitudinal dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI). In 24 rats the tumor was ablated under diffusion-weighted imaging (DWI)-guided laser interstitial thermal therapy (LITT) at post-implantation 2-weeks. Cohorts from twenty ablated rats were euthanized at post-LITT 24 h, 2- and 4-weeks and, along with 5 unablated controls, used for hematoxylin and eosin (H&amp;E) and Ki67 staining. Tissues from 4 other unablated and 4 recurrent tumors at post-LITT 2-weeks were used for RNAseq. All the rats survived the LITT procedure. Unablated controls showed increased tumor burden by post-implantation 2 weeks and were euthanized. In the LITT group, MRI showed little tumor tissue at 24 h, evidence of recurrence at 2 weeks and significant tumor tissue at 4 weeks and matched with histological evidence for tumor recurrence. Compared to the primary tumor, H&amp;E staining showed increased vascular hyperplasia, mitotic bodies and hypoxic regions with pseudopalisading necrosis in the recurrent tumor. Increased KI67 staining in recurrent tumors suggested higher rates of proliferation and evidence of infiltration into host tissue. Pathway analyses demonstrated differentially expressed genes in the canonical pathways of hypoxia-inducible factor-alpha (HIF-1α), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and OX40 signaling. The genes for the following functions were significantly affected: cell cycle, cellular movement and cell morphology. Reliable preclinical rGBM models are few. These data suggest that this model replicates the features of human rGBM and can be useful in testing putative anti-glioma therapies.

Withdrawal of antiseizure medications after MRI-Guided laser interstitial thermal therapy in extra-temporal lobe epilepsy.

This study investigated the success rate of antiseizure medications (ASMs) withdrawal following MRI Guided Laser Interstitial Thermal Therapy (MRg-LITT) for extra-temporal lobe epilepsy (ETLE), and identified predictors of seizure recurrence. We retrospectively assessed 27 patients who underwent MRg-LITT for ETLE. Patients' demographics, disease characteristics, and post-surgical outcomes were evaluated for their potential to predict seizure recurrence associated with ASMs withdrawal. The median period of observation post MRg-LITT was 3 years (range 18 - 96 months) and the median period to initial ASMs reduction was 0.5 years (range 1-36 months). ASMs reduction was attempted in 17 patients (63%), 5 (29%) of whom had seizure recurrence after initial reduction. Nearly all patient who relapsed regained seizure control after reinstitution of their ASMs regimen. Pre-operative seizure frequency (p=0.002) and occurrence of acute post-operative seizures (p=0.01) were associated with increased risk for seizure recurrence post ASMs reduction. At the end of the observation period, 11% of patients were seizure free without drugs, 52% were seizure free with drugs and 37% still experienced seizures despite ASMs. Compared with pre-operative status, the number of ASMs was reduced in 41% of patients, unchanged in 55% of them and increased in only 4% of them. Successful MRg-LITT for ETLE allows for ASMs reduction in a significant portion of patients and complete ASMs withdrawal in a subset of them. Patients with higher pre-operative seizure frequency or occurrence of acute post operative seizures exhibit higher chances relapse post ASMs reduction.

151 Intracranial Magnetic Resonance Guided Laser Interstitial Thermal Therapy for Epilepsy: A Single Institution’s Experience of 226 Cases

INTRODUCTION: Magnetic resonance guided laser interstitial thermal therapy (MRg-LITT) is a minimally invasive alternative to open surgical resection for epilepsy. Patient and technical factors associated with outcomes remain unclear. METHODS: We performed a retrospective review of consecutive patients undergoing MRg-LITT surgery at a single high-volume epilepsy center. Medical and surgical history, trajectory number per patient, adverse events, and outcomes up to 24 months were obtained and statistically analyzed. RESULTS: 203 patients underwent a total of 226 MRg-LITT procedures for epilepsy between 2011-2020. 52% and 55% of patients experienced seizure freedom at 12 and 24 months after ablation, respectively. Overall, patients with lesional epileptogenic foci were more likely to have better seizure control at 12- and 24-months after surgery (p &lt; 0.05). Of cases performed with curative intent, patients with mesial temporal sclerosis (MTS) were most likely to maintain long-term seizure freedom. Ablations performed for disconnection (corpus callosotomy) or palliation of multifocal epilepsy were unlikely to provide complete seizure freedom. 6 cases (2.7%) were complicated by intra- or post-operative hemorrhage. 3 patients (1.5%) experienced persistent post-operative complaints including cranial nerve palsy and headaches. The odds of complication (minor or major vs none) were multiplied by 1.43 for each additional trajectory (95% CI [1.16, 1.76]), and by 1.04 for each additional 1cm3 of volume ablated (95% CI [1.008, 1.076]). CONCLUSIONS: MRg-LITT, a safe and effective approach to distinct epilepsy types, appears most persistently beneficial for lesional epilepsy, particularly MTS. Although serious complications were infrequent, adverse events were statistically correlated with multiple stereotaxic trajectories and larger ablation volumes. Our results provide additional guidance for patient counseling and surgical planning.

Single-Institution Comparative Study of Magnetic Resonance–Guided Laser Interstitial Thermal Therapy and Open Corpus Callosotomy

Open corpus callosotomy (CC) poses a higher risk of perioperative morbidity than does magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) for treatment of drop and generalized seizures without documented superiority. We present a single-institution comparison between open and MRgLITT CC. A 2-year retrospective review was performed of patients who underwent open and MRgLITT CC (January 2019-January 2021). Demographics, surgical outcome data, hospital costs, and interhemispheric connectivity with diffusion tensor imaging were compared. The average age in years was 9.3 and 11.4 for CC (n= 4) and MRgLITT (n= 9), respectively. Preoperative drop seizure frequency was higher in CC (25 vs. 14.5 seizures/day; P= 0.59). At 10 months follow-up, the reduction in drop seizure frequency was better in open CC, but not statistically significant (93.8% vs. 64.3%; P= 0.21). The extent of CC ablation did not correlate with seizure reduction (Pearson coefficient= 0.09). An inverse correlation between interhemispheric connectivity change (diffusion tensor imaging analysis) and drop seizure frequency reduction was noted (Pearson coefficient= -0.97). Total hospital cost was significantly lower in MRgLITT ($67,754 vs. $107,111; P= 0.004), attributed to lower intensive care unit (1.1 vs. 4 days; P= 0.004) and total hospital stay (1.8 vs. 10.5 days; P= 0.0001). Postoperative hydrocephalus was present in 75% of patients in the CC group compared with zero in the MRgLITT group. Our middle-volume single-institution experience shows the safety, efficacy, and cost-effective benefit of MRgLITT compared with the traditional CC with therapeutic equipoise. This study is limited by the number of patients and, hence, further patient enrollment or multicenter study is warranted.

Feasibility of Transcranial Motor Evoked Potentials and Electromyography during MRI-Guided Laser Interstitial Thermal Therapy for Glioblastoma

Intraoperative neuromonitoring (IONM) is routinely used during neurosurgical procedures. Magnetic resonance imaging (MRI)-guided laser interstitial thermal therapy (LITT) is increasingly being used in patients with various brain lesions. Use of IONM (transcranial motor evoked potential [TcMEP] and electromyography [EMG]) during LITT of a brain lesion has not been described previously. In this report, we describe a 70-year-old man who presented with motor weakness in whom imaging revealed a left thalamic lesion. Due to the difficulty in accessing the lesion and proximity to the motor tracts, patient was offered MRI-guided LITT using TcMEP and EMG. The patient underwent satisfactory ablation of the lesion with successful recording of the TcMEP and EMG. Technical nuances related to the set-up and procedure is discussed in this report. No procedure-related complications were encountered. We describe the first report of safety and feasibility of TcMEP and EMG during MRI-guided LITT for left thalamic glioblasatoma. This report paves the way for further prospective investigations regarding the utility of this technique for eloquent brain tumors.

Design and Validation of a Steerable Port Delivery Cannula System for Laser Interstitial Thermal Therapy

Abstract MRI (Magnetic Resonance Imaging) guided laser interstitial thermal therapy (LITT) is a procedure used for treating glioblastomas and epilepsy lesions in the brain. Current methods for placing LITT ablation probes use straight trajectories. This limits the treatment area, necessitating multiple passes of straight trajectories or risking untreated tumor margins. This work presents a port delivery cannula system (PDCS) to be integrated within existing surgical workflows of LITT, providing off-axis navigation to areas otherwise deemed inaccessible. The design of the PDCS is centered around a two-tube, Nitinol active cannula system, which delivers, places, and retracts a flexible, thermoplastic port along curved trajectories. We present the design of the PDCS system and validate it in free-space, phantom models, and ovine brain trials, with a specific focus on evaluating key parameters of port material characteristics. Eight commercial, biocompatible ports and five custom ports created using additive manufacturing were investigated. Results illustrate that ideal port characteristics include durometers between 85A-95A, a low coefficient of friction, and a wall thickness of approximately 20% of the overall port diameter. Our results also demonstrate that the PDCS system can achieve accuracies under 1mm in phantom models and 2mm in ovine tissue.

A novel technique for frame-based MR-guided laser ablation in an infant.

Hypothalamic hamartomata (HH) not only are usually associated with drug-resistant epilepsy but can also cause precocious puberty and developmental delay. Gelastic seizures are the most common type of seizures. Magnetic resonance image (MRI)-guided laser interstitial thermal therapy (LiTT) is a technique whereby a laser fibre is stereotactically implanted into a target lesion and heat is used to ablate whilst tissue temperature is monitored using MRI thermography. MRI-guided LiTT has proven to be an effective and safe method to treat HH. To use the LiTT system, highly accurate stereotactic fibre implantation is required. This can be achieved by the use of frame-based or frameless neuronavigation techniques. However, these techniques generally involve rigid head immobilisation using cranial pin fixation. Patients need sufficient skull thickness to safely secure the pins and sufficient skull rigidity to prevent deformation. Hence, most of the clinical reports on the use of LiTT for children describe patients aged 2years or older. We report a novel and practical technique of using a paste cast helmet to securely place a stereotactic frame in a 5-month-old infant with HH and drug-resistant epilepsy that allowed the successful application of MRI-guided LiTT.

Association of intraoperative end-tidal carbon dioxide level with ablation volume during magnetic resonance-guided laser interstitial thermal therapy for mesial temporal lobe epilepsy.

Maximal safe ablation of target structures during magnetic resonance-guided laser interstitial thermal therapy (MRgLiTT) is critical to achieving good seizure outcome in patients with mesial temporal lobe epilepsy (mTLE). The authors sought to determine whether intraoperative physiological variables are associated with ablation volume during MRgLiTT. Patients with mTLE who underwent MRgLiTT at our institution from 2014 to 2019 were retrospectively analyzed. Ablation volume was determined with volumetric analysis of intraoperative postablation MR images. Physiological parameters (systolic blood pressure [SBP], diastolic blood pressure [DBP], mean arterial pressure [MAP], end-tidal carbon dioxide [ETCO2]) measured 40 minutes prior to ablation were analyzed. Univariate and multivariate regression analyses were performed to determine independent predictors of ablation volume. Forty-four patients met the inclusion criteria. The median (interquartile range) ablation volume was 4.27 (2.92-5.89) cm3, and median ablation energy was 7216 (6402-8784) J. The median MAP, SBP, DBP, and ETCO2 values measured during the 40-minute period leading up to ablation were 72.8 (66.2-81.5) mm Hg, 104.4 (96.4-114.4) mm Hg, 62.4 (54.1-69.8) mm Hg, and 34.1 (32.0-36.2) mm Hg, respectively. In univariate analysis, only total laser energy (r = 0.464, p = 0.003) and 40-minute average ETCO2 (r = -0.388, p = 0.012) were significantly associated with ablation volume. In multivariate analysis, only ETCO2 ≤ 33 mm Hg (p = 0.001) was significantly associated with ablation volume. Total ablation energy and ETCO2, but not blood pressure, may significantly affect ablation volume in mTLE patients undergoing MRgLiTT. Mild hypocapnia was associated with increased extent of ablation. Intraoperative monitoring and modulation of ETCO2 may help improve extent of ablation, prediction of ablation volume, and potentially seizure outcome.

Withdrawal of Antiepileptic Drugs After MRI–Guided Laser Interstitial Thermal Therapy in Extra-Temporal Lobe Epilepsy (P8-8.005)

Withdrawal of Antiepileptic Drugs After MRI–Guided Laser Interstitial Thermal Therapy in Extra-Temporal Lobe Epilepsy (P8-8.005)

Comparison of Surgical Outcomes in Individuals With Hypothalamic Hamartoma Alone or With Other Potentially Epileptogenic Focal Lesions

BackgroundHypothalamic hamartoma is a rare condition associated with refractory seizures. It can occur in isolation or with additional epileptogenic lesions. The aim of this study was to investigate the effects of additional potentially epileptogenic lesions on surgical outcomes in individuals with hypothalamic hamartoma. MethodsWe conducted a chart review of 112 patients with hypothalamic hamartoma who underwent magnetic resonance imaging (MRI)–guided laser interstitial thermal therapy targeted to the hypothalamic hamartoma. We compared surgical outcomes after at least six months of postoperative follow-up (N = 65) between patients with hypothalamic hamartoma alone and those with hypothalamic hamartoma plus additional potentially epileptogenic lesions. ResultsSixteen out of 112 (14%) patients had additional epileptogenic lesions, including focal cortical dysplasia, gray matter heterotopia, and polymicrogyria. Ten out of 16 patients with additional lesions and 55 out of 96 patients with hypothalamic hamartoma alone had more than six months of follow-up and are included in the outcome analysis. Mean follow-up in these patients is 21.5 ± 17.3 months (standard deviation, range: 7.3-76.8 months) for patients with hypothalamic hamartoma alone and 16.1 ± 15.0 months (standard deviation, range: 6.6-58.2 months) for those with hypothalamic hamartoma plus additional epileptogenic lesions. Fewer patients with hypothalamic hamartoma plus other lesions had Engel class I/II outcomes than patients with hypothalamic hamartoma alone (5/10 [50%] vs 46/55 [83.6%]; P = 0.031). ConclusionsMRI-guided laser interstitial thermal therapy remains an effective treatment option for patients with hypothalamic hamartoma. However, the outcome of surgical procedures targeted to the hypothalamic hamartoma may be less favorable in patients who have hypothalamic hamartoma coexisting with other potentially epileptogenic focal lesions. Thus, an additional surgical workup is warranted for these patients who have failed surgical treatment of hypothalamic hamartoma.

The American Society for Stereotactic and Functional Neurosurgery Position Statement on Laser Interstitial Thermal Therapy for the Treatment of Drug-Resistant Epilepsy.

Magnetic resonance image-guided laser interstitial thermal therapy (MRgLITT) is a novel tool in the neurosurgical armamentarium for the management of drug-resistant epilepsy. Given the recent introduction of this technology, the American Society for Stereotactic and Functional Neurosurgery (ASSFN), which acts as the joint section representing the field of stereotactic and functional neurosurgery on behalf of the Congress of Neurological Surgeons and the American Association of Neurological Surgeons, provides here the expert consensus opinion on evidence-based best practices for the use and implementation of this treatment modality. Indications for treatment are outlined, consisting of failure to respond to, or intolerance of, at least 2 appropriately chosen medications at appropriate doses for disabling, localization-related epilepsy in the setting of well-defined epileptogenic foci, or critical pathways of seizure propagation accessible by MRgLITT. Applications of MRgLITT in mesial temporal lobe epilepsy and hypothalamic hamartoma, along with its contraindications in the treatment of epilepsy, are discussed based on current evidence. To put this position statement in perspective, we detail the evidence and authority on which this ASSFN position statement is based.

Non-robotized frameless stereotactic magnetic resonance guided laser interstitial thermal therapy for hypothalamic hamartoma.

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. 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. 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 perioperative 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. 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.

Magnetic Resonance Imaging-Guided Laser Thermal Ventral Capsulotomy for Intractable Obsessive-Compulsive Disorder.

Obsessive-compulsive disorder (OCD) is a disabling condition characterized by intrusive thoughts and repetitive behaviors. A subset of individuals have severe, treatment-resistant illness and are nonresponsive to medication or behavioral therapies. Without response to conventional therapeutic options, surgical intervention becomes an appropriate consideration. To report clinical outcomes and the safety profile of bilateral ventral anterior capsulotomy for OCD using magnetic resonance (MR)-guided laser interstitial thermal therapy (LITT) in 10 patients followed for 6 to 24 mo. A total of 10 patients underwent LITT for severe OCD; 1 patient withdrew prior to follow-up. LITT is a minimally invasive ablative technique performed with precise targeting and use of thermography under MR guidance. Lesions of the ventral anterior limb of the internal capsule by other techniques have been shown to be efficacious in prior studies. A total of 7 of the 9 patients were considered full responders (77.8%; Yale-Brown Obsessive-Compulsive Scale change≥35%). Adverse effects included transient apathy/amotivation postsurgery (2 patients). One patient had a small tract hemorrhage where the laser fiber traversed the cerebral cortex as well as persistent insomnia postsurgery. One individual died after a drug overdose 7 mo postsurgery, which was judged unrelated to the surgery. LITT ventral capsulotomy was generally well tolerated, with promising evidence of effectiveness in the largest such series to date. Results were comparable to those after gamma knife ventral capsulotomy, as well as ventral anterior limb deep brain stimulation.

Awake Laser Ablation for Patients With Tumors in Eloquent Brain Areas: Operative Technique and Case Series

BackgroundMagnetic 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.ObjectiveTo describe intraoperative workflow and clinical outcomes in patients undergoing awake laser ablation of brain tumors.MethodsWe 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.ResultsThe 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.ConclusionWe propose that awake LITT is a safe approach when tumors in eloquent brain areas are considered for laser ablation.

Safety and Effectiveness of Intracranial Magnetic Resonance Thermometry Guided Laser Interstitial Thermal Therapy

Online date: November 16, 2020 This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Robot Assisted MRI-Guided LITT of the Anterior, Lateral, and Medial Temporal Lobe for Temporal Lobe Epilepsy.

Robotic systems have fundamentally altered the landscape of functional neurosurgery. These allow automated stereotaxy with high accuracy and reliability, and are rapidly becoming a mainstay in stereotactic surgeries such as deep brain stimulation (DBS), stereoelectroencephalography (SEEG), and stereotactic laser ablation/MRI guided laser interstitial thermal therapy (MRgLITT). Robotic systems have been effectively applied to create a minimally invasive approach for diagnostics and therapeutics in the treatment of epilepsy, utilizing robots for expeditious and accurate stereotaxy for SEEG and MRgLITT. MRgLITT has been shown to approach open surgical techniques in efficacy of seizure control while minimizing collateral injury. We describe the use of robot assisted MRgLITT for a minimally invasive laser anterior temporal lobotomy, describing the approach and potential pitfalls. Goals of MRgLITT are complete ablation of the epileptogenic zone and avoiding injury to uninvolved structures. In the middle fossa these include structures such as cranial nerves in the skull base and cavernous sinus and the thalamus. These can be mitigated with careful trajectory planning and control of laser ablation intensity.