Laser interstitial thermal therapy for cavernous malformations: a meta-analysis of individual patient-level data

Objective: Several case series have investigated the use of laser interstitial thermal therapy (LITT) to treat cavernous malformations (CMs), for either seizure control or reduction of neurological symptoms and future hemorrhage risk. However, pooled outcomes are largely unknown. The authors aimed to quantify posttreatment seizure freedom, symptomatic progression or hemorrhage, perioperative complications, and imaging outcomes from the available literature.

Methods: This study was a PRISMA-compliant systematic review and individual patient-level data meta-analysis of studies reporting LITT ablation of CMs. For patients with epilepsy, the pooled Engel seizure freedom rate was calculated. The rate of symptomatic progression or hemorrhage was calculated for all patients. Fixed-effects logistic regression models were used to test for predictors of seizure freedom and postoperative complications. Linear regression models were used to obtain pooled estimates of the percent CM volume ablated.

Results: A total of 39 patients (28 with epilepsy) underwent LITT for the treatment of 45 CMs (37 cortical, 8 subcortical) at six centers. Among patients with epilepsy, 88.0% (95% CI 68.7%-96.1%) were seizure free at the last follow-up (median 30.0 months, range 12.0-49.0 months). Six patients (15.4%) experienced immediate postoperative neurological deficits. No perioperative hemorrhage was reported, and no patients experienced subsequent hemorrhage or symptomatic progression during follow-up (median 26.0 months, range 2.0-53.0 months). There was no difference in the odds of seizure freedom or adverse events based on preoperative characteristics. Nonepileptogenic CMs (mean volume 2.5 cm3) were significantly larger than epileptogenic CMs (mean volume 0.8 cm3; p = 0.002). LITT was associated with a mean CM volume reduction of 73.7% (95% CI 64.1%-83.2%, p < 0.0001) for epileptogenic CMs and 53.8% (95% CI 14.2%-93.3%, p < 0.023) for nonepileptogenic CMs (p = 0.14).

Conclusions: LITT is a promising therapy for CMs with the goal of seizure control or prevention of symptomatic progression or hemorrhage. While there is a notable risk of immediate postablation neurological deficit, most were transient and nondisabling, and this risk must be weighed against that of continued observation or open resection. Considering the limited number of studies, small number of patients, and limited follow-up time available, additional experience and research with larger patient cohorts and longer-term follow-up will be necessary to validate these findings.