FUS in the treatment of Parkinson's

Focused ultrasound for ablation of the subthalamic nucleus in one hemisphere improved motor features in a selected group of patients with markedly asymmetric Parkinson's disease, but was associated with a high rate of adverse events, including dyskinesias and other neurologic complications, in a new randomized sham-controlled trial published online in the December 24 issue of the New England Journal of Medicine.

An accompanying editorial concludes that the high rate of adverse events and the lack of ability to modulate treatment over time to treat prominent tremor "raise questions about the appropriate implementation of focused ultrasound-produced lesions for the treatment of Parkinson's disease."

To avoid craniotomy and electrode penetration, MRI-guided focused ultrasound for the ablation of deep-brain structures, including the subthalamic nucleus, is being investigated as a treatment for Parkinson's disease.

Patients are potential candidates for ultrasound ablation if they have prominently asymmetric parkinsonism, if they are not considered to be clinically suitable candidates for surgery because of contraindications, or if they are reluctant to undergo a brain operation or to have an implanted device.

In this last trial the adverse events in the active-treatment group were the following:

Dyskinesia in the off-medication state in 6 patients and in the on-medication state in 6, which persisted in 3 and 1, respectively, at 4 months

Weakness on the treated side in 5 patients, which persisted in 2 at 4 months

Speech disturbance in 15 patients, which persisted in 3 at 4 months

Facial weakness in 3 patients, which persisted in 1 at 4 months

Gait disturbance in 13 patients, which persisted in 2 at 4 months

The potential advantages and limitations of focused ultrasound-produced lesioning should be discussed with patients.

Maybe if we improve the technique we will reduce the associated risks and increase the applicability of this provocative procedure