Single Trajectory Dual Targeting of Subthalamic Nucleus and Ventral Intermedius Thalamic Nucleus in Patients with Severe Tremor-Predominant Parkinson's Disease
Virgilio Gerald Evidente1, Francisco Ponce2, Danica Evidente1, Robin Lynn Garrett1, Maris Evidente1
1Movement Disorders Center of Arizona, 2Barrow Neurological Institute
Objective:
To describe clinical outcomes of severe tremor-predominant Parkinson's Disease (PD) patients who underwent single trajectory dual targeting of the subthalamic nucleus (STN) and ventral intermedius nucleus of the thalamus (VIM).
Background:
Some patients with tremor-predominant PD have a sub-optimal response to STN-DBS, whereas those that undergo VIM-DBS may have inadequate improvement of rigidity or bradykinesia. Reports on the efficacy and safety of dual target STN-VIM DBS using single trajectory are scarce.
Design/Methods:
We retrospectively reviewed the charts of all PD patients who underwent dual target STN-VIM DBS from 2012-2022 in one center. All patients were implanted bilaterally with the Boston Scientific 8-contact 15.5mm electrodes under general anesthesia using the parietal approach. Primary outcome measure was reduction in motor Unified Parkinson’s Disease Rating Scale (m-UPDRS). Secondary outcome measures include change in levodopa equivalent daily dose (LEDD) post-DBS, and time to reaching the minimum LEDD post-DBS.
Results:
12 patients (7 men) were identified. Mean age at time of surgery was 71.58±5.21 years. Mean duration of PD was 28.50±14.84 years. Mean m-UPDRS was 30.83±34.15 preDBS and 14.91±18.26 post-DBS (p<0.00000006). Mean % reduction in m-UPDRS was 50.94±0.08 %. Mean pre-DBS LEDD was 792.85±458.64, whereas post-DBS LEDD was 14.28±37.79 (p= 0.004). 7/12 were on PD medications pre-DBS: 6/7 completely weaned off medications post-DBS, and 1/7 had 89% reduction in LEDD post-DBS. The mean time to reach minimum LEDD was 33±22.87 days. Transient side effects included dysarthria (4/12), imbalance (4/12), and headaches (2/12) which improved spontaneously. 2/12 had persistent headaches which were effectively controlled with opiates. 8/12 had neuropsychological testing (NPT) pre- and post-DBS: 4/8 had no change post-DBS, 2/8 had mild worsening and 2/8 had improvement.
Conclusions:
Dual target STN-VIM DBS is very effective in treating tremor/parkinsonism in tremor-predominant PD, allowing the majority of patients to wean off PD medications. Side effects are mostly transient.