Effective Subthalamic Nucleus Deep Brain Stimulation Following MRgFUS for Tremor Dominant Parkinson's Disease

Abstract

Background Whilst MRI guided Focused Ultrasound (MRgFUS) thalamotomy is an effective treatment option for tremor disorders, there are reports of tremor recurrence in patients with tremor dominant Parkinson's disease (PD). The mechanisms for tremor recurrence are unknown but likely relate to the duality of tremor network pathways with ramifications for subsequent treatment options. Cases We report two cases of tremor dominant PD who experienced tremor recurrence following MRgFUS thalamotomy with subsequent successful subthalamic nucleus deep brain stimulation (DBS). Tremor scores were measured at baseline, 1‐ and 3‐months post MRgFUS and at least 18 months post DBS in both patients. Both cases evidenced immediate improvement in tremor, after MRgFUS, followed by subsequent tremor recurrence. STN DBS resulted in almost complete long‐term tremor alleviation in both cases. Conclusions These cases demonstrate the efficacy and feasibility of STN DBS in patients with tremor dominant PD with tremor recurrence following MRgFUS thalamotomy. We discuss the dualism of tremor outflow pathways that may have implications for single target lesional therapies.

Outcomes of Focused Ultrasound Thalamotomy in Tremor Syndromes

“…After a similar observation with a later PDT patient, we have hypothesized that the reemergence of tremor in this situation is due to the propagation of an alternative tremor network, such as the pallidothalamic tract, in a multipathway tremor disorder. 45 The results in DT patients were more aligned to those in ET patients. On direct comparison, there was no difference in any of the tremor-or quality-of-life-related outcomes between the two groups.…”

“…Further, lesional analysis in 1 patient in this series, who proceeded and benefited from STN DBS, indicated a greater than 90% interruption of the DRTT. After a similar observation with a later PDT patient, we have hypothesized that the reemergence of tremor in this situation is due to the propagation of an alternative tremor network, such as the pallidothalamic tract, in a multipathway tremor disorder 45 …”

“…The details of the first case, alongside another PDT patient with tremor relapse after MRgFUS requiring STN DBS from later on in our series, have been published by our group. Importantly, lesional analysis with posttreatment diffusion tensor imaging indicated 90% and 75% overlap between thalamotomy and dentato‐rubro‐thalamic tract (DRTT) 45 …”

“…Importantly, lesional analysis with posttreatment diffusion tensor imaging indicated 90% and 75% overlap between thalamotomy and dentato-rubro-thalamic tract (DRTT). 45…”

Early re-emerging tremor after MRgFUS thalamotomy: case–control analysis of procedural and imaging features

“…Although numerous factors that contribute to successful long-term treatment have been proposed and identified, including in previous studies by the authors, what is a common experience in many centers is the possible occurrence of tremor reoccurrence very early, within 1 month of treatment. In these cases, the determining factors often remain unclear ( 8 , 10 , 11 ).…”