A prospective single-blind study of Gamma Knife thalamotomy for tremor

Abstract

Objective: To evaluate the safety and efficacy of unilateral Gamma Knife thalamotomy (GKT) for treatment of severe tremor with a prospective blinded assessment.Methods: Fifty patients (mean age: 74.5 years; 32 men) with severe refractory tremor (36 essential, 14 parkinsonian) were treated with unilateral GKT. Targeting of the ventral intermediate nucleus (Vim) was achieved with Leksell Gamma Knife with a single shot through a 4-mm collimator helmet. The prescription dose was 130 Gy. Neurologic and neuropsychological assessments including a single-blinded video assessment of the tremor severity performed by a movement disorders neurologist from another center were performed before and 12 months after treatment. MRI follow-up occurred at 3, 6, and 12 months. Results:The upper limb tremor score improved by 54.2% on the blinded assessment (p , 0.0001). All tremor components (rest, postural, and intention) were improved. Activities of daily living were improved by 72.2%. Cognitive functions remained unchanged. Following GKT, the median delay of improvement was 5.3 months (range 1-12 months). The only side effect was a transient hemiparesis associated with excessive edema around the thalamotomy in one patient. Conclusion:This blinded prospective assessment demonstrates that unilateral GKT is a safe and efficient procedure for severe medically refractory tremor. Side effects were rare and transient in this study. Classification of evidence:This study provides Class IV evidence that for patients with severe refractory tremor, GKT is well tolerated and effective in reducing tremor impairment. The pharmacologic treatment for severe tremor can be disappointing.

Effects on cognition and quality of life with unilateral magnetic resonance–guided focused ultrasound thalamotomy for essential tremor

“…1,9,26,30,35,41 Despite their delivered improvement in tremor, these therapeutic modalities are often accompanied by adverse effects on speech or language. Recently, a meta-analysis demonstrated that speech difficulty occurred in 19.8% of patients after RF thalamotomy and 19.4% after DBS.…”

Ablative surgery for Parkinson’s disease: Is there still a role for pallidotomy in the deep brain stimulation era?

“…This modality of treatment is more established for essential tremor, with prospective studies showing symptomatic improvement in both techniques [95,96]. For PD, however, better results are being reported for focused ultrasound [97,98], with an additional safety of performing a pre-lesioning of the targeted area before thethermal coagulation is done, therefore reducing the risks of undesired side-effects.…”

Stereotactic Radiosurgery for Intractable Tremor-Dominant Parkinson Disease: A Retrospective Analysis

“…Lim et al [21] reported 3 PD patients who had sustained tremor relief after GKT. Ohye et al [22] described outcomes in 59 PD patients, while Witjas et al [25] reported 14 PD patients who were enrolled in a prospective single-blind study. Overall, GKT for PD tremor was associated with a small risk of adverse radiation effects, resulting in temporary hemiparesis or dysphasia [18,19,20,21,22,23,24].…”