Peeters Nicky, Van Campenhout Anja, Hanssen Britta, Cenni Francesco, Schless Simon-Henri, Van den Broeck Christine, Desloovere Kaat, Bar-On Lynn
Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium.
Department of Rehabilitation Sciences, University of Ghent, Ghent, Belgium.
Front Neurol. 2020 Apr 21;11:210. doi: 10.3389/fneur.2020.00210. eCollection 2020.
Botulinum NeuroToxin-A (BoNT-A) injections to the medial gastrocnemius (MG) and lower-leg casts are commonly combined to treat ankle equinus in children with spastic cerebral palsy (CP). However, the decomposed treatment effects on muscle or tendon structure, stretch reflexes, and joint are unknown. In this study, BoNT-A injections to the MG and casting of the lower legs were applied separately to gain insight into the working mechanisms of the isolated treatments on joint, muscle, and tendon levels. Thirty-one children with spastic CP (GMFCS I-III, age 7.4 ± 2.6 years) received either two weeks of lower-leg casts or MG BoNT-A injections. During full range of motion slow and fast passive ankle rotations, joint resistance and MG stretch reflexes were measured. MG muscle and tendon lengths were assessed at resting and at maximum dorsiflexion ankle angles using 3D-freehand ultrasound. Treatment effects were compared using non-parametric statistics. Associations between the effects on joint and muscle or tendon levels were performed using Spearman correlation coefficients ( < 0.05). Increased joint resistance, measured during slow ankle rotations, was not significantly reduced after either treatment. Additional joint resistance assessed during fast rotations only reduced in the BoNT-A group (-37.6%, = 0.013, effect size = 0.47), accompanied by a reduction in MG stretch reflexes (-70.7%, = 0.003, effect size = 0.56). BoNT-A increased the muscle length measured at the resting ankle angle (6.9%, = 0.013, effect size = 0.53). Joint angles shifted toward greater dorsiflexion after casting (32.4%, = 0.004, effect size = 0.56), accompanied by increases in tendon length (5.7%, = 0.039, effect size = 0.57; = 0.40). No associations between the changes in muscle or tendon lengths and the changes in the stretch reflexes were found. We conclude that intramuscular BoNT-A injections reduced stretch reflexes in the MG accompanied by an increase in resting muscle belly length, whereas casting resulted in increased dorsiflexion without any changes to the muscle length. This supports the need for further investigation on the effect of the combined treatments and the development of treatments that more effectively lengthen the muscle.
肉毒杆菌神经毒素A（BoNT-A）注射到腓肠肌内侧（MG）和小腿石膏固定通常联合用于治疗痉挛性脑瘫（CP）患儿的足踝马蹄内翻畸形。然而，对于肌肉或肌腱结构、牵张反射及关节的分解治疗效果尚不清楚。在本研究中，分别应用BoNT-A注射到MG和小腿石膏固定，以深入了解单独治疗在关节、肌肉和肌腱水平的作用机制。31例痉挛性CP患儿（GMFCS I-III级，年龄7.4±2.6岁）接受为期两周的小腿石膏固定或MG的BoNT-A注射。在全范围运动中，进行缓慢和快速被动踝关节旋转时，测量关节阻力和MG牵张反射。使用3D徒手超声在静息和最大背屈踝关节角度评估MG肌肉和肌腱长度。使用非参数统计比较治疗效果。使用Spearman相关系数（<0.05）分析关节与肌肉或肌腱水平的效应之间的相关性。在缓慢踝关节旋转期间测量的关节阻力增加，两种治疗后均未显著降低。仅在快速旋转期间评估的额外关节阻力仅在BoNT-A组中降低（-37.6%，=0.013，效应大小=0.47），同时MG牵张反射降低（-70.7%，=0.003，效应大小=0.56）。BoNT-A增加了在静息踝关节角度测量的肌肉长度（6.9%，=0.013，效应大小=0.53）。石膏固定后关节角度向更大背屈方向移位（32.4%，=0.004，效应大小=0.56），同时肌腱长度增加（5.7%，=0.039，效应大小=0.57；=0.40）。未发现肌肉或肌腱长度变化与牵张反射变化之间存在关联。我们得出结论，肌肉内注射BoNT-A可降低MG的牵张反射，同时静息肌腹长度增加，而石膏固定导致背屈增加，肌肉长度无任何变化。这支持了对联合治疗效果进行进一步研究以及开发更有效延长肌肉的治疗方法的必要性。
