Frameless robot-assisted pallidal deep brain stimulation surgery in pediatric patients with movement disorders: precision and short-term clinical results

Abstract

Objective: The purpose of this study was to verify the safety and accuracy of the Neuromate stereotactic robot for use in deep brain stimulation (DBS) electrode implantation for the treatment of hyperkinetic movement disorders in childhood and describe the authors' initial clinical results.

Methods: A prospective evaluation of pediatric patients with dystonia and other hyperkinetic movement disorders was carried out during the 1st year after the start-up of a pediatric DBS unit in Barcelona. Electrodes were implanted bilaterally in the globus pallidus internus (GPi) using the Neuromate robot without the stereotactic frame. The authors calculated the distances between the electrodes and their respective planned trajectories, merging the postoperative CT with the preoperative plan using VoXim software. Clinical outcome was monitored using validated scales for dystonia and myoclonus preoperatively and at 1 month and 6 months postoperatively and by means of a quality-of-life questionnaire for children, administered before surgery and at 6 months' follow-up. We also recorded complications derived from the implantation technique, "hardware," and stimulation.

Results: Six patients aged 7 to 16 years and diagnosed with isolated dystonia ( DYT1 negative) (3 patients), choreo-dystonia related to PDE2A mutation (1 patient), or myoclonus-dystonia syndrome SGCE mutations (2 patients) were evaluated during a period of 6 to 19 months. The average accuracy in the placement of the electrodes was 1.24 mm at the target point. At the 6-month follow-up, patients showed an improvement in the motor (65%) and functional (48%) components of the Burke-Fahn-Marsden Dystonia Rating Scale. Patients with myoclonus and SGCE mutations also showed an improvement in action myoclonus (95%-100%) and in functional tests (50%-75%) according to the Unified Motor-Rating Scale. The Neuro-QOL score revealed inconsistent results, with improvement in motor function and social relationships but worsening in anxiety, cognitive function, and pain. The only surgical complication was medial displacement of the first electrode, which limited intensity of stimulation in the lower contacts, in one case.

Conclusions: The Neuromate stereotactic robot is an accurate and safe tool for the placement of GPi electrodes in children with hyperkinetic movement disorders.

Keywords: AC = anterior commissure; BFMDRS = Burke-Fahn-Marsden Dystonia Rating Scale; DBS = deep brain stimulation; EEG = electroencephalographic; GPi = globus pallidus internus; MDS = myoclonus-dystonia syndrome; PC = posterior commissure; SEEG = stereoelectroencephalography; UMRS = Unified Myoclonus Rating Scale; dystonia; frameless; functional neurosurgery; movement disorders; myoclonus dystonia syndrome; pediatric deep brain stimulation; robotic arm.