Van Campenhout Anja, Bar-On Lynn, Desloovere Kaat, Huenaerts Catherine, Molenaers Guy
Department of Orthopaedics, University Hospital Leuven, Leuven, Belgium; KU Leuven Department of Development and Regeneration, Leuven, Belgium.
Dev Med Child Neurol. 2015 May;57(5):476-83. doi: 10.1111/dmcn.12667. Epub 2015 Jan 2.
Intramuscular botulinum toxin-A (BoNT-A) injections reduce spasticity by blocking neurotransmission at the motor endplate (MEP). The goal of this study was to assess the reduction in spasticity achieved by injecting BoNT-A at different sites of the gracilis muscle.
Thirty-four gracilis muscles, in 27 children (10 females and 17 males, mean age of 8.6y [SD 2.5y]) with spastic cerebral palsy (unilateral and bilateral, Gross Motor Function Classification System [GMFCS] levels I-IV), were randomly assigned to one of two groups. In one group BoNT-A was injected proximally (at a site 25% of the distance from the pubic tubercle and the medial epicondyle) and in the other it was injected at the MEP zones (half of the dose was administered at 30% of this distance and half at 60%). Spasticity was assessed before and after BoNT-A injection using simultaneous measurements of surface electromyography (sEMG) and angular velocity during passive muscle stretch applied at different velocities. The primary outcome measure included the velocity-dependent change in average root mean square electromyography (RMS-EMG). Secondary outcome was assessed with the Modified Ashworth Scale (MAS) and Modified Tardieu Scale (MTS).
Spasticity decreased more in MEP-targeted muscles than in proximally injected muscles, as demonstrated by a larger reduction in average RMS-EMG values (p=0.04), though this difference was not found with the MAS or MTS.
The results suggest that BoNT-A injection of the gracilis at sites with a high concentration of MEPs is effective at reducing spasticity. These preliminary findings should be confirmed by larger studies. In the case of long muscles, such as the gracilis, the injection site is important.
肌内注射A型肉毒毒素（BoNT-A）通过阻断运动终板（MEP）处的神经传递来减轻痉挛。本研究的目的是评估在股薄肌不同部位注射BoNT-A所实现的痉挛减轻程度。
将27名痉挛型脑瘫儿童（10名女性和17名男性，平均年龄8.6岁[标准差2.5岁]，单侧和双侧，粗大运动功能分类系统[GMFCS] I-IV级）的34块股薄肌随机分为两组。一组在近端注射BoNT-A（在耻骨结节与内上髁距离的25%处），另一组在运动终板区域注射（一半剂量在该距离的30%处给药，另一半在60%处给药）。在注射BoNT-A前后，通过在不同速度下进行被动肌肉拉伸时同步测量表面肌电图（sEMG）和角速度来评估痉挛程度。主要结局指标包括平均均方根肌电图（RMS-EMG）的速度依赖性变化。次要结局用改良Ashworth量表（MAS）和改良Tardieu量表（MTS）进行评估。
以运动终板为靶点的肌肉痉挛减轻程度大于近端注射的肌肉（平均RMS-EMG值下降幅度更大，p=0.04），不过在MAS或MTS评估中未发现这种差异。
结果表明，在运动终板浓度高的部位注射BoNT-A对减轻股薄肌痉挛有效。这些初步发现应通过更大规模的研究加以证实。对于像股薄肌这样的长肌肉，注射部位很重要。
