MRI-Guided Focused Ultrasound Subthalamotomy for Treating Parkinson Disease

A group of researchers assessed the safety and effectiveness of staged bilateral MRI-guided focused ultrasound subthalamotomy (FUS-STN) to treat Parkinson Disease (PD). The study was conducted between June 18, 2019, and November 7, 2023, at the HM-CINAC Puerta del Sur University Hospital in Madrid, Spain.

Participants included 6 patients with who had been treated with unilateral FUS-STN contralateral to their most affected body side and whose disease had progressed on the untreated side and was not “optimally controlled with medication.” They were also required to have been treated on their most affected body side during a previous FUS-STN pilot study or randomized clinical trial. However, patients were excluded from this study if they had experienced any permanent adverse events from the first FUS-STN trial.

The primary outcomes of the study were safety and effectives. Safety was assessed by treatment-related complications after the second FUS-STN. Effectiveness was based on change in the motor score on the Movement Disorders Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS III) in the off-medication state (ie, after at least 12 hours of antiparkinsonian drug withdrawal). Both outcomes were measured 6 months after the second FUS-STN procedure.

The results showed that of 45 patients with PD who were treated with unilateral FUS-STN in the initial pilot and randomized studies, 6 patients—3 women and 3 men with a median age of 52.6 years at the time of the first FUS-STN—underwent a second FUS-STN. Four of these patients presented with contralateral choreic dyskinesia, which resolved by 3 months. In addition, four patients developed speech disturbances, which gradually improved but remained in a mild form for two patients at 6 months. Mild imbalance and dysphagia occurred in one patient during the first week after treatment, which subsided by 3 months. The researchers did not find any behavioral or cognitive disturbances during neuropsychological testing.

In terms of efficacy, MDS-UPDRS III scores improved by 52.6% between baseline and 6 months after the second FUS-STN procedure. The second treated side improved by 64.3% prior to the second treatment.

Overall, the researchers found that bilateral FUS-STN was safe and effective for the treatment of PD. Although adverse events occurred, they were mostly mild and transient. There were mild speech disturbances that persisted in 2 patients at 6 months, but motor improvement was significant.

“All patients reported global benefit, suggesting that adverse events did not diminish the net improvement in motor manifestations. In our study, speech disturbances were mild and did not interfere with communication,” said the authors.

Reference

Martínez-Fernández R, Natera-Villalba E, Rodríguez-Rojas R, et al. Staged bilateral MRI-guided focused ultrasound subthalamotomy for Parkinson Disease. JAMA Neurol. 2024;81(6):638-644. doi: 10.1001/jamaneurol.2024.1220