互助与希望社区

标题: 神经阻滞术 [打印本页]

作者: 怡诚爸爸 时间: 2011-5-4 23:30
标题: 神经阻滞术
转帖自香港江志强医生的个人主页，可惜现在找不到他的链接地址了。

神经阻断﹙nerve block﹚是用酚﹙phenol﹚或酒精注射到控制痉挛肌肉的运动神经周围，借着降低神经的传导功能，来治疗痉挛。

治疗痉挛的有效期由数月至年半不等。（看来并非是把神经杀死，而只是降低神经的传导功能）

神经阻断可与造模配合使用，伸展受痉挛及挛缩影响的关节。

如想对神经阻断的进行过程有更深入的了解，可进入神经阻断技术篇。

作者: 怡诚爸爸 时间: 2011-5-4 23:31
神经阻断与肉毒杆菌毒素的比较

神经阻断及肉毒杆菌毒素是治疗痉挛的有效方法。

神经阻断每次注射治疗的范围较大，涵括接受注射神经的所有肌肉，而不能选择个别肌肉接受治疗；但这亦是神经阻断的长处，即可用非常局部的注射，而放松大范围的肌肉。要达致有选择性及局部放松的效果，可采用肌内注射法﹙intramuscular injection﹚或神经分枝阻断法。

肉毒杆菌毒素的治疗较为局部及可选择个别肌肉注射，但若治疗的范围较大则需接受多个位置的注射。

肉毒杆菌毒素只作用于运动神经末梢；神经阻断则同时作用于运动及感觉神经，故小部分接受治疗的病人可能会有短暂的痹痛感觉。

肉毒杆菌毒素的治疗有效期一般只有数月，神经阻断的治疗有效期则可长达年半，所以需要接受再注射的次数会较少。

作者: 怡诚爸爸 时间: 2011-5-4 23:40
案例一

  评估的医生右手上的是一个力度表﹙dynamometer﹚，用以测量右手推起小腿的力度；左手则固定膝盖。

左图医生正用５磅力将小腿抬高，但因大腿后肌痉挛及挛缩，以致难以将膝关节伸展。

[attach]1193[/attach]

  接受酚神经阻断﹙phenol nerve block﹚后，大腿后肌的延伸性明显加强；同样用５磅力将小腿抬起，膝关节比治疗前更易伸展。

[attach]1194[/attach]

  再经过约两星期，日间数小时及夜间配带矫形支具后，膝关节的延伸性得到进一步的改善。

[attach]1192[/attach]

作者: 怡诚爸爸 时间: 2011-5-4 23:43
经临床检查后，首先选择需要阻断的神经。

可能需要注射安静剂，以方便进行神经阻断。

进行神经阻断时，先在特定的位置插入可注射阻断药的电针。

[attach]1195[/attach]

　

利用电流的刺激，并在适当的肌肉接收讯号，准确地找出神经的正确位置。

跟着便注射阻断药﹙例如：酚﹙phenol﹚﹚，阻断选定的神经。

作者: 怡诚爸爸 时间: 2011-5-4 23:44
Introduction:

Neural block means the application of chemical agents to a nerve to impair the conduction along the nerve. Chemical neurolysis is a form of nerve block that the nerve conduction impairment is achieved by destruction of a portion of a nerve.

Functional nerve block without actual nerve destruction usually has short lasting effect. It is usually performed for local anesthetic purposes. Chemical neurolysis has more persistent effect and so it is a more appropriate choice for treatment of spasticity.

Phenol and alcohol are two agents commonly used for chemical neurolysis. This article would concentrate on the discussion of phenol block.

Historical Background:

Use of intrathecal phenol for the treatment of spasticity was first reported  in 1950s (Nathan; Kelly & Gauthier-Smith). Perineural phenol block and intramuscular phenol injections have been  subsequently performed for relief of spasticity since 1960s.

Physiological Effects:

Perineural block with aqueous phenol of concentrations less than 2% will have only local anesthetic properties. It may cause some microvascular damage to the nerve but no significant nerve destruction.

At concentrations more than 3%, phenol denatures protein and causes nerve destruction with axonal degeneration.

Differential Effect:

It is commonly observed after nerve block that voluntary strength is often more preserved in the good relief of spasticity. It was first speculated that phenol may preferentially destroy sensory fibres with resulting reduced spasticity and preserved muscle power. This speculation was not substantiated after the animal histological studies which showed similar degenerations of all types of fibres.

Interruption of both sensory and motor pathways may be already sufficient to explain this observation. The synergistic effect of  interruption of both the sensory and motor pathways contributes to the reduced reflex contraction  while the interruption of the motor pathway alone affects the active muscle strength. In addition, gamma efferents which is part of the motor pathway act functionally as afferents since the interruption of the gamma efferents causes relaxation of the intrafusal fibres. The result is a reduction of reflex contraction and spasticity.

Clinical Applications in Cerebral Palsy:

Phenol nerve block can be used for the treatment of spasticity in cerebral palsied children. Concentrations below 3% usually give unsatisfactory results. Frequent repetition of nerve blocks may be required. In clinical practice the most commonly used concentrations are between 3 - 6%.

Compared with the Botulinum toxin injection, phenol may have more adverse effects. Technically it is also more difficult. It however have more persistent effect and so may require less injections. The treatment involves all muscles the blocked nerve supplies. It hence has the advantage of relieving the spasticity of the whole muscle group with a single injection. On the other hand, it has the disadvantage of poorer selectivity.

As the nerve is recovering by axonal regeneration, the muscle strength and spasticity return. At concentrations above 3%, the effect lasting more than a year is not uncommon.  There are some factors that may affect the effects and duration of the treatment. These include concentration and volume of injection, subsequent treatments such as stretching and casting, and presence of selective control. However, there is no control study on these issues.

The treatment is useless to contracture. It nevertheless could be used with casting to relieve and tackle the problems of spasticity and contracture at the same time. Phenol has the additional advantage of anesthesia  to relieve the pain of stretching. Phenol block and Botulinum toxin may be used in the same child so that the large muscle groups are treated with phenol block while the selected individual small muscles are treated with Botulinum toxin.

Adverse Effects:

There are some adverse effects that may be associated with the phenol injection. These include:

Burning pain on injection

Dysesthesia - described as burning paresthesia, usually lasts several weeks only

Vascular complications

Skin sloughing

Injection Technique:

Electrodes are placed to a muscle supplied by the selected nerve for picking up compound motor action potential (CMAP). Electrical stimulation is given at the tip of a  Teflon coated injection needle  which is inserted at a pre-determined standard point. The needle is connected to a syringe containing phenol for injection (see picture on 技術篇). Adjustment of needle tip is guide by the CMAP response elicited by the electrical stimulation. After locating the nerve by fine adjustments, phenol is injected following the attempted but empty blood aspiration, in order to avoid the accidental intravascular injection. It is a perineural block. Direct nerve injection may lead to nerve palsy.

Conclusion:

The technique is not new. Clinically the treatment appears effective in decreasing spasticity. There is however no good control studies to document its effectiveness. Recent popularity of Botulinum toxin leads to a recurrence of the interests on the use of nerve block. It has been reported to be safe and useful in treating children with cerebral palsy. It probably could be considered as one of the useful treatment options of spasticity. It is also a very economic treatment.

作者: 淼淼妈 时间: 2011-5-10 15:21
本帖最后由 mydhsh 于 2020-8-13 17:43 编辑

第三方代孕--可混血--可选男女-可双胞胎。：溦`信：【ivf 2 2 2 2】服务项目：试管婴儿（试管二、三代技术）（可以提供性别筛选）（包成功男、女孩）（精与卵供应不需排队等待）（早期血液性别鉴定）第三方代孕，无身体接触 招聘代妈【有怀孕经验的优先】

作者: 曾曾妈妈 时间: 2012-1-30 16:40
怡诚爸爸您好！我们家孩子就张力一直降不下，康复了4年了，都没大的效果，这种阻断术我也去刘建军教授那咨询过，他说能做，可我一直犹豫，因为听说会反弹的，您对这个了解吗？
请问淼淼妈，现在孩子打完肉毒术的效果怎样？

欢迎光临互助与希望社区 (http://www.help-hope.org/)