Abstract
Objectives To report the long-term outcomes in Tremor-Dominant Parkinson Disease (TDPD) after a unilateral Focused Ultrasound (FUS) thalamotomy; and explore factors that may predict the outcome.
Method Retrospective blinded video assessment of consecutive TDPD patients who underwent a unilateral FUS thalamotomy was undertaken. Patients were classified into two groups: ‘responder’ (R) (>50% improvement in Hand Tremor Score at last follow-up) or ‘suboptimal responder’ (SR) (<50% improvement in HTS). Patient and treatment parameters were compared between the two groups.
Results From November 2018, to February 2023, 17 patients with TDPD underwent a unilateral FUS thalamotomy at our centre. Pre- and post-operative videos were available in 15 patients for analysis (age 71.5±6.3 y.o, disease duration 7.3±8.0 years, baseline HTS 12.7±5.5, follow-up 18.7±13.7 months). The R group included 7 patients with a HTS of 1.7±1.5 at the last follow-up (19.7±13.9 months), compared to 8 patients in the SR group, with a HTS of 16.5±9.9 at a mean follow-up time of 14.3±13.7 months. There were no baseline differences between the groups. Tremor in the untreated hand was greater in the SR’s compared to R’s following treatment (8.9±5.4 vs. 1.3±1.9, p<0.001).
Conclusion In the long-term, unilateral FUS thalamotomy for TDPD improved tremor by greater than 50% in approximately a half of patients. Baseline clinical features and treatment parameters, including thalamotomy lesion volume did not predict the ‘responder’ from ‘suboptimal responder’ groups. Suboptimal long-term response may be related to progression of Parkinson’s disease, in these patients.
