Gallay Marc N, Moser David, Jeanmonod Daniel
J Neurosurg. 2020 Feb 7;134(2):376-385. doi: 10.3171/2019.12.JNS192219. Print 2021 Feb 1.
In addition to the well-recognized ventral intermediate nucleus (Vim) thalamotomy for the treatment of chronic therapy-resistant essential tremor (ET), an alternative approach targeting the posterior part of the subthalamus was proposed in the 1960s and early 1970s and then was reactualized as cerebellothalamic tractotomy (CTT) with the advent of MR-guided focused ultrasound (MRgFUS) surgery. The goal of this study was to improve target coverage and thus efficacy (i.e., tremor control and its consistency). The authors undertook a histological reappraisal of the CTT target and proposed a targeting strategy of the MRgFUS CTT based on 1) the MR visualization of the center of the red nucleus and 2) the application of preplanned target subunits realized with short sonications under thermal dose control. This study was aimed at demonstrating the efficacy and risk profile of this approach against chronic therapy-resistant ET.
Ten consecutive patients suffering from chronic therapy-resistant ET benefited from a unilateral MRgFUS CTT and were followed over the course of 1 year. Primary endpoints were subjective tremor relief, Clinical Rating Scale for Tremor (CRST) score, activities of daily living (ADL) score, and the hand function (HF) scores HF16 and HF32. Histological reappraisal of the target led the authors to propose a standardized targeting protocol for MRgFUS CTT. Thermal doses for 18 and 240 cumulative equivalent minutes at 43°C were calculated and correlated with intraoperative and 2 days postoperative T2-weighted MR images.
The mean ± SD for the baseline CRST score was 48 ± 12; the score was 16 ± 7 at 3 months, and 17 ± 8 at 1 year. The mean tremor relief rated by the patients for the operated side was 95% after 2 days, 96% at 3 months, and 93% at 1 year. The mean HF16 was 11.0 ± 2.1 at baseline, 0.7 ± 0.7 at 3 months, and 0.8 ± 0.9 at 1 year (93% mean reduction). The minimum reduction for the HF16 at 1 year was 78%. There was a 51% reduction of the mean ADL score at 1 year. There was no bleeding or infection. Gait difficulties, only detectable on tandem gait, were increased in 3 patients and reduced in 2 patients at 1 year. There was no dysarthria.
The authors' results suggest that MRgFUS CTT is a very effective treatment option for therapy-resistant ET.
除了广为人知的丘脑腹中间核（Vim）毁损术用于治疗慢性难治性特发性震颤（ET）外，20世纪60年代和70年代初还提出了一种针对丘脑底核后部的替代方法，随着磁共振引导聚焦超声（MRgFUS）手术的出现，该方法又重新兴起，即小脑丘脑束切断术（CTT）。本研究的目的是提高靶点覆盖范围，从而提高疗效（即震颤控制及其一致性）。作者对CTT靶点进行了组织学重新评估，并基于以下两点提出了MRgFUS CTT的靶向策略：1）红核中心的磁共振可视化；2）在热剂量控制下通过短时间超声处理实现预先规划的靶点亚单位的应用。本研究旨在证明这种方法治疗慢性难治性ET的疗效和风险特征。
连续10例患有慢性难治性ET的患者接受了单侧MRgFUS CTT治疗，并随访1年。主要终点包括主观震颤缓解情况、震颤临床评分量表（CRST）得分、日常生活活动（ADL）得分以及手功能（HF）评分HF16和HF32。对靶点的组织学重新评估使作者提出了MRgFUS CTT的标准化靶向方案。计算了43℃下18和240累积等效分钟的热剂量，并将其与术中及术后2天的T2加权磁共振图像相关联。
基线CRST评分的平均值±标准差为48±12；3个月时评分为16±7，1年时评分为17±8。患者对手术侧的平均震颤缓解率在术后2天为95%，3个月时为96%，1年时为93%。HF16的平均值在基线时为11.0±2.1，3个月时为0.7±0.7，1年时为0.8±0.9（平均降低93%）。1年时HF16的最小降低率为78%。1年时ADL评分的平均值降低了51%。未发生出血或感染。1年时，仅在串联步态时可检测到的步态困难在3例患者中加重，在2例患者中减轻。未出现构音障碍。
作者的结果表明，MRgFUS CTT是治疗难治性ET的一种非常有效的治疗选择。
