Sheean Geoffrey
University of California, San Diego, California 92103-8465, USA.
Drug Saf. 2006;29(1):31-48. doi: 10.2165/00002018-200629010-00003.
Injections of botulinum toxin have revolutionised the treatment of focal spasticity. Before their advent, the medical treatment for focal spasticity involved oral anti-spasticity drugs, which had decidedly non-focal adverse effects, and phenol injections. Phenol injections could be difficult to perform, could cause sensory complications and had effects that were of uncertain duration and magnitude. Furthermore, few neurologists knew how to perform them as they were mostly the province of rehabilitation specialists. Botulinum toxin can produce focal, controllable muscle weakness of predictable duration, without sensory adverse effects. Randomised clinical trials (RCTs) involving patients with spasticity resulting from a variety of diseases (mainly stroke and multiple sclerosis) have clearly shown that botulinum toxin type A (Dysport and Botox) can temporarily (for approximately 3 months) reduce spastic hypertonia in the elbow, wrist and finger flexors of the upper limbs, and the hip adductors and ankle plantar flexors in the lower limbs. The clinical benefits from this reduction of neurological impairment are best shown in the upper limb, with less disability of passive function and reduced caregiver burden. In the lower limbs, there is improved perineal hygiene from hip adductor injections. The benefits of reducing ankle plantar flexor tone are less well established. Pain is also reduced, possibly by mechanisms other than muscle weakness. Improved active function has not yet been clearly demonstrated in RCTs, only in open-label trials. The safety of botulinum toxin-A is impressive, with minimal (mainly local) adverse effects. There are little data on the use of botulinum toxin type B (Myobloc or Neurobloc) in spasticity and the only RCT that has examined this did not show tone reduction; dry mouth appeared to be a very common adverse effect. There are also very little data to allow a benefit-risk comparison of phenol and botulinum toxin injections; each have their clinical and technical advantages and disadvantages, and phenol is much less costly than botulinum toxin.
肉毒杆菌毒素注射彻底改变了局灶性痉挛的治疗方法。在其出现之前，局灶性痉挛的药物治疗包括口服抗痉挛药物，这些药物具有明显的非局灶性副作用，以及苯酚注射。苯酚注射操作可能困难，会引起感觉并发症，且效果持续时间和程度不确定。此外，很少有神经科医生知道如何进行苯酚注射，因为这主要是康复专科医生的领域。肉毒杆菌毒素可产生持续时间可预测的局灶性、可控性肌肉无力，且无感觉副作用。涉及因各种疾病（主要是中风和多发性硬化症）导致痉挛的患者的随机临床试验（RCT）清楚地表明，A型肉毒杆菌毒素（Dysport和保妥适）可暂时（约3个月）降低上肢肘部、腕部和手指屈肌，以及下肢髋内收肌和踝跖屈肌的痉挛性高张力。这种神经功能障碍减轻带来的临床益处在上肢表现最为明显，被动功能残疾减少，护理人员负担减轻。在下肢，髋内收肌注射可改善会阴部卫生。降低踝跖屈肌张力的益处尚不明确。疼痛也可能通过肌肉无力以外的机制减轻。RCT中尚未明确证明主动功能有所改善，仅在开放标签试验中有此显示。A型肉毒杆菌毒素的安全性令人印象深刻，副作用极小（主要是局部性的）。关于B型肉毒杆菌毒素（Myobloc或Neurobloc）用于痉挛治疗的数据很少，唯一一项对此进行研究的RCT未显示肌张力降低；口干似乎是一种非常常见的副作用。也几乎没有数据可用于对苯酚和肉毒杆菌毒素注射进行利弊比较；两者各有临床和技术上的优缺点，且苯酚的成本比肉毒杆菌毒素低得多。
