Clinical Efficacy and Safety Profile of Anterior Thalamic Stimulation for Intractable Epilepsy

Abstract

Introduction Deep brain stimulation of the anterior nucleus of the thalamus (ANT DBS) is a neuromodulation therapy for patients with refractory partial seizures. The ANT is the structure of a limbic system with abundant neuronal connections to temporal and frontal brain regions that participate in seizure propagation circuitry. State of the Art We have performed a literature search regarding the clinical efficacy of ANT DBS. We discuss the surgical technique of the implantation of DBS electrodes with special attention paid to the targeting methods of the ANT. Moreover, we present in detail the clinical efficacy of ANT DBS, with a special emphasis on the stimulation parameters, a stimulation mode, and polarity. We also report all adverse events and present the current limitations of ANT DBS. Clinical Implications In general, the safety profile of DBS in intractable epilepsy patients is good, with a low rate of surgery, hardware-related, and stimulation-induced adverse events. No significant cognitive declines or worsening of depressive symptoms was noted. At long-term follow-up, the quality-of-life scores have improved. The limitations of ANT DBS studies include a limited number of patients treated and mostly open-label designs with only one double-blind, randomized multicenter trial. Most studies do not report the etiology of intractable epilepsy or they include nonhomogeneous groups of patients affected by intractable epilepsy. There are no guidelines for setting initial stimulation parameters. All the variables mentioned may have a profound impact on the final outcome. Conclusions ANT DBS appears to be a safe and efficacious treatment, particularly in patients with refractory partial seizures (three-quarters of patients gained at least 50% seizure reduction after 5 years). ANT DBS reduces most effectively the seizures originating in the temporal and frontal lobes. The published results of ANT DBS highlight promise and hope for patients with intractable epilepsy.

Assessing short‐term and long‐term security and efficacy of anterior nucleus of the thalamus deep brain stimulation for treating drug‐resistant epilepsy: A systematic review and single‐arm meta‐analysis

“…Regarding complications, there was no procedure‐related mortality detected. Table 2 summarizes the short‐term outcomes data, in which were included studies with a mean follow‐up of less than or equal to 3 years, totaling 14 studies 2,6,19,21,24,25,29–32,34–37 …”

“…In order to assess correctly the outcomes associated with the surgery, we divided their presentation into two distinct periods. First, we evaluated all of the outcomes reported in a short‐term period, comprising 14 studies 2,6,19,21,24,25,29–32,34–37 . Next, we assessed all of the outcomes provided by 11 references in a long‐term period 3,5,13,14,20,22,23,26–28,33 .…”

Deep brain stimulation suppresses epileptic seizures in rats via inhibition of adenosine kinase and activation of adenosine A1 receptors

“…ANT is a crucial node in the Papez circuit and has abundant projections to the frontal and temporal cortex 6,7 . This explains why ANT‐DBS most effectively reduces seizures originating in the temporal and frontal lobes 8 …”

“…6,7 This explains why ANT-DBS most effectively reduces seizures originating in the temporal and frontal lobes. 8 Pilocarpine injections in rodents provide a suitable model for studying DRE. Pilocarpine epileptic rat models have long-term seizures and show extensive cell loss, which resembles what has been discovered in patients with temporal lobe epilepsy.…”