METHODS: MRgFUS thalamotomy was performed in a 60-year-old left-handed patient for his disabling medically refractory essential tremor. The intervention resulted in a marked reduction of his action tremor. However, the patient developed an unvoluntary abnormal posture in his left hand a few days after the procedure with difficulty holding a cigarette between his fingers. Brain MRI revealed the expected MRgFUS lesion within the right V.im as well as an extension of the lesion anteriorly to the V.im in the ventro-oralis nucleus. Tractography showed that the lesion disrupted the dentato-rubro-thalamic tract as expected with a lesion suppressing tremor. However, the lesion also was interrupted fibers connecting to the superior frontal and pre-central cortices (primary motor cortex, premotor cortex, and supplementary area). We hypothesized that the interventional MRgFUS thalamotomy was slightly off target, which induced a dysfunction within the cortico-striato-thalamo-cortical network and the cerebello-thalamo-cortical pathway reaching a sufficient threshold of basal ganglia/cerebellum circuitry interference to induce dystonia.
CONCLUSIONS: This rare side effect emphasizes the risk of imbalance within the dystonia network (i.e., basal ganglia-cerebello-thalamo-cortical circuit) secondary to V.im thalamotomy.
方法:对一名60岁的左撇子患者进行了MRgFUS丘脑切开术,因为他的医学难治性特发性震颤致残。干预导致他的动作震颤明显减少。然而,手术后几天,患者的左手出现了非自愿的异常姿势,手指之间很难握住香烟。脑部MRI显示右侧V.im内预期的MRgFUS病变,以及前口核V.im的病变向前延伸。气管造影显示,病变如预期的那样破坏了牙本质-红斑-丘脑束,并抑制了震颤。然而,病变也是连接到上额叶和中央前皮质(初级运动皮质,运动前皮质,和补充区域)。我们假设介入MRgFUS丘脑切开术稍微偏离目标,它在皮质-纹状体-丘脑-皮层网络和小脑-丘脑-皮层通路内引起功能障碍,达到足够的基底神经节/小脑电路干扰阈值,以诱导肌张力障碍。
结论:这种罕见的副作用强调了肌张力障碍网络内失衡的风险(即,基底神经节-小脑-丘脑-皮层回路)继发于丘脑切开术。