A Systematic Review of Minimally Invasive Procedures for Mesial Temporal Lobe Epilepsy: Too Minimal, Too Fast?

Abstract

BACKGROUND Cortico-amygdalohippocampectomy (CAH) is effective for mesial temporal lobe epilepsy (mTLE). Concerns regarding surgical morbidity have generated enthusiasm for more minimally invasive interventions. A careful analysis of current data is warranted before widespread adoption of these techniques. OBJECTIVE To systematically review the use of laser interstitial thermal therapy (LITT), stereotactic radiosurgery (SRS), radiofrequency thermocoagulation (RF-TC), and focused ultrasound for mTLE. METHODS Major online databases were searched for prospective observational studies, randomized clinical trials, and retrospective studies (>50 patients), including mTLE patients. Outcomes of interest were seizure freedom (Engel I), complications and re-operation rates, and neuropsychological and quality-of-life (QoL) data. RESULTS Nineteen publications were identified. At ≥6 mo postoperatively, LITT (9/19) Engel I outcomes ranged from 52% to 80%. SRS (3/19) has a latency period (52%-67%, 24-36 mo postoperatively) and the radiosurgery vs. open surgery for epilepsy (ROSE) trial reported inferiority of SRS compared to CAH. RF-TC (7/19) demonstrated variable seizure freedom rates (0%-79%) and high re-operation rates (0%-90%). Twelve studies reported neuropsychological outcomes but QoL (4/19) was not widely reported, and few studies (3/19) assessed both. Study quality ranged from fair to good. CONCLUSION Based on nonrandomized data, LITT has compelling evidence of efficacy; however, comparisons to surgical resection are lacking. SRS has a latency period and is inferior to CAH (ROSE trial). RF-TC is a less resource-intensive alternative to LITT; however, comparisons of efficacy are limited. Additional studies are needed before minimally invasive procedures can supplant standard surgery.

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

“…It is possible, however, that LITT effectiveness is overestimated due to a positive reporting bias associated with novel technologies (halo effect), a reluctance to publish poor outcomes, shorter follow up durations and overcoming of learning curves. A systematic review comparing only the minimally invasive techniques LITT, RF-TC and SRS concluded that LITT shows promising seizure efficacy in the short-term ( 65 ). Our linear-regression model results provide a much-needed statistical analysis of the data in comparison to open surgical methods to further support LITT as an emerging technique, but long-term follow ups and direct comparisons are needed to form a firm conclusion.…”

Timing of referral to evaluate for epilepsy surgery: Expert Consensus Recommendations from the Surgical Therapies Commission of the International League Against Epilepsy

“…Focused ultrasound also has a potential use for neuromodulation in epilepsies 29 . There is compelling evidence of efficacy for these emerging minimally invasive approaches, 30,31 but recent meta‐analyses suggest waning seizure freedom over time across all types of epilepsy surgery, most noticeable in minimally invasive approaches 32,33 . Overall, rigorous research is still needed to adequately resolve controversies regarding the long‐term risks and benefits.…”

Recent advances in epilepsy surgery

“…Over the last decade, multiple case series have reported promising short-term results of LITT in DRE. Two recent systematic reviews showed that seizure-freedom after LITT ranges between 33 and 77.8%; however, the long-term Engel I outcomes have been shown to decrease to 50% after 5 years of follow-up [40,44]. LITT has higher rates (60-89%) of seizure-freedom in DRE associated with mesial temporal sclerosis and hypothalamic hamartomas [40].…”

“…Two recent systematic reviews showed that seizure-freedom after LITT ranges between 33 and 77.8%; however, the long-term Engel I outcomes have been shown to decrease to 50% after 5 years of follow-up [40,44]. LITT has higher rates (60-89%) of seizure-freedom in DRE associated with mesial temporal sclerosis and hypothalamic hamartomas [40]. Moreover, recent studies have reported better naming and object recognition outcomes after LITT in dominant hemisphere epilepsy compared with standard ATL [45].…”