Milanese, Vanessa

OBJECTIVE Open resective surgery (ORS) has become the standard of care for focal drug-resistant epilepsy (DRE). However, minimally invasive surgical alternatives, such as laser interstitial thermal therapy (LITT), have also been shown to be safe and effective. A meta-analysis comparing both treatments is warranted to assess the benefits of each modality for focal DRE. METHODS A literature search was conducted until March 14, 2024, to identify studies comparing LITT and ORS in patients with DRE. The primary outcomes included seizure freedom (SF), length of hospital stay (LHS), and complication rate (CR). Subgroup analyses were performed based on age, epilepsy etiology, and propensity score–matched (PSM) studies. RESULTS Of 558 articles, 15 cohort studies met the authors’ inclusion criteria, encompassing 3873 patients for analysis. The rate of SF in the LITT group was 52.5% (95% CI 0.453–0.597, I 2 = 47.4%) and 67.1% (95% CI 0.602–0.739, I 2 = 57.4%) for the ORS group. LITT showed a significantly lower rate of SF compared to ORS (risk ratio [RR] 0.78, 95% CI 0.70–0.88, p ≤ 0.0001). However, when PSM studies (RR 0.85, 95% CI 0.63–1.15, p = 0.30) and studies on patients with temporal lobe epilepsy (TLE) (RR 0.88, 95% CI 0.67–1.14, p = 0.34) were analyzed, the SF rates were similar. Patients who underwent LITT had a significantly shorter LHS (mean difference 2.95 days, 95% CI 1.12–4.78, p < 0.00001), lower CR (RR 0.54, 95% CI 0.37–0.79, p < 0.002, I 2 = 32%), lower rate of ischemic stroke (RR 0.15, 95% CI 0.04–0.65, p = 0.01), and lower rate of permanent neurological deficits (RR 0.13, 95% CI 0.05–0.36, p < 0.0001). CONCLUSIONS Across unmatched studies evaluating focal DRE, ORS showed a higher rate of SF. However, pooled matched-cohort analyses showed no difference between interventions in achieving SF, a trend also noted in the authors’ PSM TLE sample. LITT, however, offered significantly shorter LHS and lower CRs. Future prospective studies should match patient populations to control for confounding factors and assess key outcomes, such as postoperative neurocognitive follow-up and quality of life measurements, in order to fully evaluate the risks and benefits of each approach.

Abstract Objective In patients with focal drug‐resistant epilepsy (DRE), resective epilepsy surgery correlates with high rates of remission. However, in cases where the epileptic region is deemed surgically inaccessible, or when it involves a complex network, stereoelectroencephalography‐guided radiofrequency thermocoagulation (SEEG‐RFTC) might be an alternative therapeutic strategy. However, most of the available evidence is limited to small observational studies. An updated meta‐analysis is warranted to provide a comprehensive assessment of SEEG‐RFTC in patients with DRE. Methods Databases were searched until September 9, 2023 to identify published studies reporting on the effectiveness of SEEG‐RFTC in patients with DRE. The primary outcomes of interest were the 1‐year seizure‐freedom rate and response rate (50% seizure frequency decrease from baseline). These outcomes were pooled using the inverse variance and a random‐effects model. Results We screened 182 articles and included 16 retrospective cohort studies. A total of 437 unique patients from 12 nonoverlapping cohorts were analyzed for seizure and complication outcomes. The pooled seizure‐free rate after 1 year was 37.8% (95% confidence interval [CI] = 24.7%–50.8%), whereas the seizure response rate after 1 year was 69.7% (95% CI = 52.7%–86.7%). There was high heterogeneity among the included studies. Subgroup analysis revealed that patients with nodular heterotopia achieved higher rates of seizure freedom (57.1%, 95% CI = 38.8%–75.5%) compared to those with cortical dysplasia (CD) and magnetic resonance imaging‐negative conditions. Furthermore, hippocampal sclerosis patients exhibited higher seizure freedom rates (66.7%, 95% CI = 49.8%–83.5%) than those with CD (12.0%, 95% CI = .0%–24.7%). Significance SEEG‐RFTC might be an effective therapeutic option for seizure control in patients with DRE who undergo SEEG for DRE workup. The role of SEEG‐RFTC as a potential adjunct therapy to laser interstitial thermal therapy or surgical resection should be explored. This study highlights the need for well‐designed clinical trials to compare SEEG‐guided RFTC with other therapeutic modalities.

Abstract Patient-specific targeting of the Ventral intermediate nucleus (Vim) of the thalamus can be achieved with MR connectivity. Nevertheless, there are several drawbacks to using tractography-based targeting methods to visualise distinct thalamic nuclei (e.g., subjective region of interest selection, and thresholding of resulting tracts and clusters). Fractional anisotropy (FA) mapping, another product of diffusion MRI (dMRI), does not rely on tractography, and could thus be clinically more viable for discerning thalamic anatomy for stereotactic surgery. The aim of this study is to develop and present a hybrid, high-resolution, and high-fidelity imaging modality that combines contrast from FA maps as well as anatomical T1 sequences (FAT1 imaging); and to evaluate FAT1 based Vim-target definition. Imaging and outcome data of 35 consecutive refractory tremor patients who had undergone 43 connectivity guided deep brain stimulation (DBS) and/or radiofrequency thermocoagulation (RF-T) between 2013 and 2021 were included. First, the pre-operatively acquired dMRI and MPRAGE sequences were used to create FAT1 maps in retrospect. Then, an FAT1 based Vim-target was planned by an experienced functional neurosurgeon who was blinded for patient outcome. Finally, to investigate FAT1 based targeting, a post-hoc analysis was carried out of the degree of overlap between the newly created FAT1 based Vim-target, and the volume of tissue activation (VTA, in case of DBS) or lesion volume (in case of RF-T). This degree of overlap was compared between favourable and unfavourable outcome groups: outcomes were measured by experts blinded for imaging data at the last follow-up using a Clinical Global Impression-Improvement score (CGI-I), where a CGI-I score of 1-2 (i.e., FTMTRS improvement of ≥50%) was considered favourable. In 36 of the 43 (84%) performed surgeries (24 DBS and 19 RF-T), FAT1 based Vim-targeting was possible. For the group showing favourable outcome (71% of the patients at a median follow-up of 13 months), the mean amount of overlap between the FAT1 based Vim-target and the VTA or lesion was 42% (±13), versus 17% (±15) for patients with an unfavourable outcome (MD 25%, 95% CI 14–35, p &lt; 0.0001). Retrospective use of FAT1 based Vim-targeting as a tool to predict outcome had a sensitivity of 90%, specificity of 80%, positive predictive value of 90%, and negative predictive value of 80%. In conclusion, FAT1 imaging is a new, high-resolution, and high-fidelity modality that combines diffusion and anatomical MRI. It provides a fast and efficacious way of targeting the ventral intermediate nucleus of the thalamus. In this study, FAT1 based targeting was highly accurate in predicting outcomes after deep brain stimulation and radiofrequency thalamotomy.