Resective, Ablative and Radiosurgical Interventions for Drug Resistant Mesial Temporal Lobe Epilepsy: A Systematic Review and Meta-Analysis of Outcomes

Abstract

Objectives: One-third of individuals with focal epilepsy do not achieve seizure freedom despite best medical therapy. Mesial temporal lobe epilepsy (MTLE) is the most common form of drug resistant focal epilepsy. Surgery may lead to long-term seizure remission if the epileptogenic zone can be defined and safely removed or disconnected. We compare published outcomes following open surgical techniques, radiosurgery (SRS), laser interstitial thermal therapy (LITT) and radiofrequency ablation (RF-TC).Methods: PRISMA systematic review was performed through structured searches of PubMed, Embase and Cochrane databases. Inclusion criteria encompassed studies of MTLE reporting seizure-free outcomes in ≥10 patients with ≥12 months follow-up. Due to variability in open surgical approaches, only comparative studies were included to minimize the risk of bias. Random effects meta-analysis was performed to calculate effects sizes and a pooled estimate of the probability of seizure freedom per person-year. A mixed effects linear regression model was performed to compare effect sizes between interventions.Results: From 1,801 screened articles, 41 articles were included in the quantitative analysis. Open surgery included anterior temporal lobe resection as well as transcortical and trans-sylvian selective amygdalohippocampectomy. The pooled seizure-free rate per person-year was 0.72 (95% CI 0.66–0.79) with trans-sylvian selective amygdalohippocampectomy, 0.59 (95% CI 0.53–0.65) with LITT, 0.70 (95% CI 0.64–0.77) with anterior temporal lobe resection, 0.60 (95% CI 0.49–0.73) with transcortical selective amygdalohippocampectomy, 0.38 (95% CI 0.14–1.00) with RF-TC and 0.50 (95% CI 0.34–0.73) with SRS. Follow up duration and study sizes were limited with LITT and RF-TC. A mixed-effects linear regression model suggests significant differences between interventions, with LITT, ATLR and SAH demonstrating the largest effects estimates and RF-TC the lowest.Conclusions: Overall, novel “minimally invasive” approaches are still comparatively less efficacious than open surgery. LITT shows promising seizure effectiveness, however follow-up durations are shorter for minimally invasive approaches so the durability of the outcomes cannot yet be assessed. Secondary outcome measures such as Neurological complications, neuropsychological outcome and interventional morbidity are poorly reported but are important considerations when deciding on first-line treatments.

Temporal lobe epilepsy surgery: Piriform cortex resection impacts seizure control in the long‐term

“…Additionally, the resection of at least 27% of the PiC was associated with a high rate (79%) of seizure freedom in long‐term FU. These findings are in line with previously reported series on patients with mTLE following tsSAHE 10,16 . In the present study, we for the first time show that an extent of PiC resection above 27% of PiC volume is the only independent significant predictor for reduction or withdrawal of AEDs during the long‐term FU following tsSAHE.…”

“…These findings are in line with previously reported series on patients with mTLE following tsSAHE. 10,16 In the present study, we for the first time show that an extent of PiC resection above 27% of PiC volume is the only independent significant predictor for reduction or withdrawal of AEDs during the longterm FU following tsSAHE. The analysis of further Values indicated in mL.…”

“…[7][8][9] Despite the rising utility of these minimally invasive treatment methods, the surgical treatment still remains the standard of care in drug-resistant epilepsy. 10,11 In the treatment for mesial TLE (mTLE), the reported seizure freedom rates offered for tsSAHE range between 60% and 70%. Beyond these successfully treated cases, there is a considerable amount of patients with persistent seizures after resective epilepsy surgery.…”

“…During the last years, novel minimally invasive technologies such as laser interstitial thermotherapy (LITT) are increasingly gaining interest 7–9 . Despite the rising utility of these minimally invasive treatment methods, the surgical treatment still remains the standard of care in drug‐resistant epilepsy 10,11 . In the treatment for mesial TLE (mTLE), the reported seizure freedom rates offered for tsSAHE range between 60% and 70%.…”

Current trends and hotspots in drug-resistant epilepsy research: Insights from a bibliometric analysis

“…A single-center study including pediatric patients with drug-resistant lesional epilepsy showed that Engel class I outcome was achieved in 41% patients ( 41 ). In a quantitative analysis of novel “minimally invasive” approaches, the pooled seizure-free rate per person-year was 0.59 with LITT and 0.38 with RF-TC, which were not as efficacious as open surgery ( 42 ). Nevertheless, LITT and RF-TC remain surgical options, even as a first-line treatment for certain epilepsy indications, while more high-quality evidence is needed.…”