Objective: To define topography that correlates with tremor control after unilateral focused ultrasound (FUS) thalamotomy for tremor-dominant Parkinson´s Disease (TDPD).

Background: Unilateral FUS thalamotomy of the ventral intermediate nucleus (Vim) is safe and effective to treat parkinsonian tremor. Recent reports show some degree of variability in tremor improvement and risk of relapse.

Method: Retrospective study. The analysis included consecutive patients with medical-refractory TDPD who underwent unilateral FUS thalamotomy (2015-2021). Patients were classified into two groups: “optimal responders” (tremor improvement>70% according to MDS-UPDRS-III subitems in the last assessment, median follow-up of 6 months) and “suboptimal responders” (tremor improvement<70%). Lesion topography was assessed at 24-hour brain MRI including the total volume of the lesion as well as the overlap with the Vim and the immediate ventral subthalamic area.

Results: Thirty-four TDPD patients (age 72.5+6.7y; disease duration 7.8+4.9y) were included. At baseline, total MDS-UPDRS III was 39.5+11.7, with 7.5+1.9 points for tremor on the most affected side. The optimal sustained response group (n=14) presented a 93+8% for total tremor improvement, and 98+9%, 96+13%, 96+13% for postural, action, and resting tremor, respectively). The suboptimal response group (n=20) improved 27+29% for total tremor (48+31%, 18+35% and 25+32% for postural, action and resting tremor, respectively). Two patients required retreatment due to a meaningful relapse. Lesions leading to sustained optimal improvement had larger volumes (155+56 vs 279+206mm3, p=0.0461) and impacted the dorsal region of the STN (17+18 vs 39+37mm3, p=0.0477), with a similar impact onto the Vim in both groups (p=0.1456). Adverse events (imbalance, dysmetria, finger/lip paresthesia, dysgeusia, clumsiness, dysarthria) were similar in both groups and most were mild, transient and disabling.

Conclusion: In TDPD patients, larger lesions onto the Vim extending to the dorsal region of the STN were related to better results in terms of tremor control and sustained clinical benefit.

References: • Bond AE, Shah BB, Huss DS, Dallapiazza RF, Warren A, Harrison MB, Sperling SA, Wang XQ, Gwinn R, Witt J, Ro S, Elias WJ. Safety and Efficacy of Focused Ultrasound Thalamotomy for Patients With Medication-Refractory, Tremor-Dominant Parkinson Disease: A Randomized Clinical Trial. JAMA Neurol. 2017 Dec 1;74(12):1412-1418. doi: 10.1001/jamaneurol.2017.3098. PMID: 29084313; PMCID: PMC5822192.
• Yamamoto K, Ito H, Fukutake S, Odo T, Kamei T, Yamaguchi T, Taira T. Focused Ultrasound Thalamotomy for Tremor-dominant Parkinson’s Disease: A Prospective 1-year Follow-up Study. Neurol Med Chir (Tokyo). 2021 Jul 15;61(7):414-421. doi: 10.2176/nmc.oa.2020-0370. Epub 2021 May 8. PMID: 33967176; PMCID: PMC8280323.
• Bruno F, Catalucci A, Arrigoni F, Gagliardi A, Campanozzi E, Corridore A, Tommasino E, Pagliei V, Pertici L, Palumbo P, Sucapane P, Cerone D, Pistoia F, Di Cesare E, Barile A, Ricci A, Marini C, Splendiani A, Masciocchi C. Comprehensive Evaluation of Factors Affecting Tremor Relapse after MRgFUS Thalamotomy: A Case-Control Study. Brain Sci. 2021 Sep 9;11(9):1183. doi: 10.3390/brainsci11091183. PMID: 34573204; PMCID: PMC8472207.
• Sinai A, Nassar M, Sprecher E, Constantinescu M, Zaaroor M, Schlesinger I. Focused Ultrasound Thalamotomy in Tremor Dominant Parkinson’s Disease: Long-Term Results. J Parkinsons Dis. 2022;12(1):199-206. doi: 10.3233/JPD-212810. PMID: 34602500; PMCID: PMC8842770.

« Back to 2023 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/optimal-topographic-characteristics-of-focused-ultrasound-unilateral-thalamotomy-for-tremor-dominant-parkinsons-disease/