A prospective single-blind study has demonstrated the safety and efficacy of Gamma Knife thalamotomy for severe medically refractory tremor. The study was published online ahead of print in the journal Neurology.
Tatiana Witjas (Department of Neurology and Movement Disorders, Timone University Hospital, Marseille, France) et al treated 50 patients (mean age: 74.5 years; 32 men) with severe refractory tremor (36 essential, 14 parkinsonian) with unilateral Gamma Knife thalamotomy. Targeting of the ventral intermediate nucleus (Vim) was achieved with Leksell Gamma Knife (Elekta) with a single shot through a 4mm collimator helmet. The prescription dose was 130Gy.
Neurological and neuropsychological assessments including a single-blinded video assessment of the tremor severity performed by a movement disorders neurologist from another centre were performed before and 12 months after treatment. MRI follow-up occurred at three, six, and 12 months.
The authors report: “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%, and cognitive functions remained unchanged. Following Gamma Knife thalamotomy, the median delay of improvement was 5.3 months (range 1–12 months).”
The only side effect observed was a transient hemiparesis associated with excessive oedema around the thalamotomy in one patient.
Witijas et al conclude that this blinded prospective assessment “demonstrates that unilateral Gamma Knife thalamotomy is a safe and efficient procedure for severe medically refractory tremor”, and that this study “provides Class IV evidence that for patients with severe refractory tremor, Gamma Knife thalamotomy is well tolerated and effective in reducing tremor impairment”.