Stereo-electroencephalography (SEEG) has been shown to be a valuable tool for the anatomo-electroclinic definition of the epileptogenic zone (EZ) in some patients with medically refractory epilepsy considered for surgery. In Spain, many of those patients are not offered this diagnostic procedure. The objective of our health technology assessment (HTA) report was to evaluate the effectiveness, safety and cost-effectiveness of SEEG to define the EZ in patients with refractory epilepsy considered for surgery compared to no SEEG intervention (i.e. remaining with further antiepileptic drugs).

We undertook a systematic review with meta-analyses on the effectiveness and safety of SEEG. A cost-effectiveness analysis was conducted using a Markov model which simulates the costs and health outcomes of individuals for a lifetime horizon from the perspective of the Spanish National Health Service (NHS). The effectiveness measure was quality-adjusted life years (QALYs). We ran extensive sensitivity analyses, including a probabilistic sensitivity analysis.

The EZ was found in 92 percent of patients who underwent SEEG, 72 percent were eligible for epilepsy surgery and 33 percent were free of seizures after surgery (47 percent of those who received surgery). Any complications related to insertion and monitoring of SEEG and the subsequent intervention occurred in 1.3 percent of patients. In the base case analysis, SEEG led to higher QALYs and healthcare costs with an estimated incremental cost-effectiveness ratio of EUR 10,368 (USD 12,217) per QALY. The sensitivity analyses showed that the results of the study were robust.

SEEG is a cost-effective technology in patients with refractory epilepsy considered for surgery when compared to no SEEG intervention.