Safety and feasibility of deep brain stimulation of the anterior cingulate and thalamus in chronic refractory neuropathic pain: a pilot and randomized study.

BACKGROUND

Deep Brain Stimulation (DBS) of the anterior cingulum has been recently proposed to treat refractory chronic pain but its safety and its efficacy have not been evaluated in controlled conditions. Our objective was to evaluate the respective feasibility and safety of sensory thalamus (Thal-DBS) combined with anterior cingulate (ACC-DBS) DBS in patients suffering from chronic neuropathic pain.

METHODS

We conducted a bicentric study (clinicaltrials.gov NCT03399942) in patients suffering from medically-refractory chronic unilateral neuropathic pain surgically implanted with both unilateral Thal-DBS and bilateral ACC-DBS, to evaluate successively: Thal-DBS only; combined Thal-DBS and ACC-DBS; ACC-DBS "on" and "off" stimulation periods in randomized cross-over double-blinded conditions; and a 1-year open phase. Safety and efficacy were evaluated by repeated neurological examination, psychiatric assessment, comprehensive assessment of cognitive and affective functioning. Changes on pain intensity (Visual Analogic Scale) and quality of life (EQ-5D scale) were used to evaluate DBS efficacy.

RESULTS

All the patients (2 women, 6 men, mean age 52,1) completed the study. Adverse events were: epileptic seizure (2), transient motor or attention (2), persistent gait disturbances (1), sleep disturbances (1). No patient displayed significant cognitive or affective change. Compared to baseline, the quality of life (EQ-5D utility score) was significantly improved during the ACC-DBS "On" stimulation period (p = 0,039) and at the end of the study (p = 0,034).

CONCLUSION

This pilot study confirmed the safety of anterior cingulate DBS alone or in combination with thalamic stimulation and suggested that it might improve quality of life of patients with chronic refractory neuropathic pain.

TRIAL REGISTRATION: The study has been registered on 20,180,117 (clinicaltrials.gov NCT03399942).